
<h1>Introduction</h1>

This is a nearly blow by blow journal of rebuilding a 1 Joule
Lumonics / JK Lasers ruby laser and making a hologram with it.  It contains
a great many inaccuracies 
and incorrect conclusions, but I wanted to leave them in to document the
process of their correction.  So read it all the way to the end.
<p>

<h1>20101229</h1>

Arrival

IMAGES:20101227
IMAGES:20101229
IMAGES:20101231

<h1>20110103</h1>

Scrubbing bubbles:

<P>
The coolant lines are coated on the inside with dried out something.  Probably
algae.  Replacing the tubing in the umbilical would be a nightmare.  I've
been circulating water through it in an effort to dissolve things.  Adding
bubbles to the water with an aquarium pump improves the scrubbing, without
being chemical or abrasive.  Just don't add too many, or the pump stalls.

<h1>20110105</h1>

<P>
All the micrometers and adjustment screws for the optics were goo-ed.  The
lubricant was all dried up and nearly frozen.  I got all but the lower screw
on the output coupler un-wedged, soaking everything with WD40 and then wiping
out all the threads with q-tips.  Hopefully WD40 will get the last screw
un-frozen.

<P>
Minor q-switch enlightenment:  it could be going from negative 3.2k to 0, to
positive 3.2k.  That makes the "balance" control on the original q-switch 
driver a little more logical as well.  It adjusts the voltage the first
SCR stack switches.

<h1>20110107</h1>

energy management card component substitutions:

<pre>
2N2647 unijunction transistor  2N6027?  (30V 300mw SCR)
  there are /no/ SMT unijunction transistors

BC107/BC109  NPN small signal for general purpose amp
  107 is slightly higher voltage rating than 109 
  BC546 is modern part (more or less) and should work for both  (No SMT)
  2PD601ASL,215  is SMT.  There is weirdness with the hfe.

1N4148  100V 200ma rectifier  currently available   Yes SMT
2N4402 bipolar small signal PNP available but getting obscure  No SMT
  771-PZT2907A-T/R  SMT  
  BSR16   MMBT4403
  
3.9V zener
5.6V zener

741 opamp   324?  
I2C controlled POT?
  DAC7571IDBVTG4   0 to 5V I2C DAC  12 bit
  DAC8571IDGKR     0 to 5V I2C DAC  16 bit
  These will need an opamp to negate and get to 15V for the existing circuit

4093: quad 2 input NAND Schmitt triggers high voltage (20V).

</pre>

Also disconnected the pump chambers from the coolant loop, and put some
cascade in to try and clean out the algae.  With the aquarium pump, it made
some pretty impressive foam.

IMAGES:20110106
IMAGES:20110107

<h1>20110108</h1>
<p>
Assembled the cooler.  
<p>
The first plan was to put the de-ionizing cartridge in line with the laser.
That didn't work, the pump couldn't get enough water through the cartridge.
So, put the cartridge in parallel with the laser.  That worked better, but
the pump was not able to reliably trip the pressure switch for the laser's
interlock.  Except that then it started being reliable.    (and problems
which go away on their own, come back on their own.)

<p>
The laser should really have a flow sensor, not a pressure sensor.  And the
fitting at the bottom of the tank (Home Despot bucket) is leaking.  Epoxy
is apparently compatible with de-ionized water.
<p>
See <a href="http://www.coleparmer.com/techinfo/chemcomp.asp"> http://www.coleparmer.com/techinfo/chemcomp.asp</a>


IMAGES:20110108
<h1>20110110</h1>

<p>
The YAG controller, while mechanically compatible, IS NOT electrically
compatible.
V.35 connectors are lettered, not numbered, so the schematics are useless for
determining pin-outs.  From continuity probing, the various 220V hot and 
neutrals would have been more or less shuffled, and probably dead-shorted.

<p>
An adaptor would have to be built, involving two V.35 connectors at $22 each.
MEH.  So the question is whether to press on with testing with existing
hardware, or go straight for the re-engineered one.

<p>
The cooler is no longer leaking, and still does not reliably trip the pressure
sensor.  The current plan is to reverse supply and return, so the pressure
sensor is further up-stream, and sees more pressure.  The ideal plan would
be to replace it with a flow sensor.

IMAGES:20110110
<h1>20100112</h1>

<p>
M.34 connectors are obscenely expensive.  The pins are $2 each.  But replacing
the connectors on the capacitor cabinet would suck even more.  This does mean
I've bailed on buying a female connector to do an adaptor for the YAG 
controller.  I'll attempt to rearrange its pins instead.  That will allow me 
to observe what the original circuitry does.

<p>
Unijunction transistors are also surprisingly expensive, though mostly because
the minimum order is 500 of them.  Its an archaic component, used for simple
oscillators.  I think I'll replace it with a 555.  They are also archaic, but
are currently available.


IMAGES:20110112
<h1>20100116</h1>

<p>
After much poring over schematics, I've convinced myself that the YAG
controller is in-fact electrically compatible.  All the pins line up, and
all the signal lines (SCR, PD2000) go to the right places.  All the shields
being tied together with frame GND threw me off.

<p>
So, I applied power.  The interlock was not closed.  After some debugging
it was determined that the interlock override switch is defective.  That is
not a part I would expect to fail.  On attempt number 2, there was the
usual explosions flames and smoke.

<p>
C3 on the power card exploded.  It was an old tantalum so that may not be
surprising.  It went from the +15V rail to GND, after the regulator.

<p>
R22 on the energy control card also smoked.  It went from the +15V rail
to R19, R31, and C10, on the top of TR2, which then drives the shunt SCR.
The SCR is driven through a transformer, so I'm hoping the SCR is undamaged.
The transformer's coil is 3.7 ohms, which matches the other SCR's transformer.

<p>
I should have replaced caps before proceeding.  I suspect C10 is shorted.
Dan suggests that TR2 might also be dead.

<p>
More substitute components:
<pre>
2N4402:  BSR16   MMBT4403
</pre>


<h1>20110118</h1>

Resonator dimensions:

<pre>
Based on measuring image 20110118/dscn6938.jpg
Rods are 13mm diameter.
Bottom two are 118 mm apart  (center to center)
Side two are 87mm apart (center to center)

Or in imperial units:
Rods are 0.5 inches diameter
Bottom two are 4 5/8 apart (center to center)
Side two are 3.4111261794  or 3 and 6 or 7 16'ths

Neither of these measurements really make me confident.  Re-measure with
a pair of calipers...

Rods are 0.5 inches diameter
Bottom two are  4 9/16 apart (center to center)
Side two are 3 11/32 apart (center to center)
</pre>

IMAGES:20110118
<h1>20110123</h1>

<p>
Fabricated the alignment laser mount.  Ordered a whole horde o' hardware
from Mcmaster-carr, since the alignment laser needed longer #4 screws.

<p>
The circuit breakers (for controller) and transistor sockets (for q-switch)
are much cheaper via ebay.  The question is how many transistor sockets 
to get, given the active-low requirement.  The qswitch's use of a TNC
connector also complicates things, can't float both ends above GND.

IMAGES:20110123
<h1>20110125</h1>

<p>
Beam height is 2 5/16.  maybe...

<p>
Got the alignment laser assembled, with external batteries, and rough-aligned
through all the optics.  Need to determine the actual beam height, make an
alignment card, put a pin hole on the alignment laser, and then actually
align it.

<p>
I've decided to get 30 transistor sockets.  Which will probably mean I need
more.

IMAGES:20110125
<h1>20110126</h1>

<p>
Noticed a bunch of damage on the pulse generator card.  pin 4, which is
the +15 rail, vaporized a bunch of traces, and some components.  I suspect
the +15 rail had more of a voltage excursion than I thought...

<p>
The power card is acting like a dead short.  Bad 7815?  The 3A version is
unavailable from mouser or digikey.

<p>
When you plug in the cabinet, something clicks quietly.  (I believe its the
OV card)
When you close the circuit breaker, +48V is turned on (from T3).  
When you turn the key, and the interlock is closed, the +48V is used to
close R1 on the charger chassis.  Its loud...
That applies 220VAC to T2, through Fuse 1 (which may be a self-resetting
circuit breaker).  Which applies 18VAC to the power supply card in the
controller, and 480V to the trigger card.  

<pre>
Circuit breakers: mouser 691-BA2B034615221D ( manufacturer BA2-B0-34-615-221-D)
momentary key switch: mouser 642-JD-7510A ($13)
   or 642-A018302 ($30, 10x lifetime)

momentary button, want LEDs?  MP0042/1
</pre>

IMAGES:20110126
<h1>20110128</h1>

<p>
I moved the taps on T3 and T2 from the 200 to the 240V pins.  The 48V rail
is now 50V, instead of 60, the 18V rail is 19VAC, and the 435V rail is
about 440V.  That may have caused the excursion on the 15VDC rail, but I
thought that a 7815 was rated for more like 35V input.

<p>
The voltage taps on T1, the big charging transformer, are not labeled.

<p>
I've also gotten the alignment laser more or less aligned down the middle of
the resonator.  It still needs a pinhole.  The beam height is 2 3/8 inches
above the rail.

IMAGES:20110128
<h1>20110129</h1>

<p>
The 7815 regulator is fried.  The rectifier, filter caps, and 7915 are OK
though.  I believe that the problem was that the YAG laser used low voltage
dump relays, while this ruby uses 220VAC dump relays.  So the 220V got
into the 15V rail, and Bad Things Happened.

<p>
Lots more reverse-engineering.  I believe I can now get power all the way
to the energy control card, after fixing the 7815 problem.  Bypass the 
220VAC dump relay circuit through the controller.  I've ordered some circuit
breakers.  Need to order some buttons and a key switch.  Should the buttons
be 220VAC, like the original circuitry, or more 48VAC relay stuff?

<p>
The next question is what frequency is used to couple through the transformers
to drive the SCRs, and what the horde o' weird transistor circuitry is supposed
to be doing.

<p>
Then, on to re-engineering the energy control card with i2c stuff pondered
above.

<p>
Then, there is the pulse generator card.  What sort of pulse does the 
trigger card need?  I'd rather replace the pulse generator card with an MSP430
doing the same timer trick as was done on the q-switch driver.

<p>
And then there is the q-switch driver question.  Plan A is to find a 1/4 wave
plate, to reverse the sense of the q-switch.  Plan B is to make a much more
annoying waveform.  Blea.

<p>
***  Disconnected wire 66 from TB1/L, moved wire 32 from TB1/K to TB1/L ***
That forces the dump relays closed, and removes the 240VAC stuff from the
YAG controller's low voltage dump relay circuitry.  I only did that on
the OSC, not the AMP.

IMAGES:20110129
<h1>20110205</h1>

<p>
I moved the taps on the big transformer (T1) from the 220 to the 240V pin.

<p>
The schematics I have are for a more recent version of the energy control
card and pulse generator card.  The actual hardware uses MHTL logic.
Motorola's MHTL logic family: Motorola High Threshold Logic.  Allegedly
very high noise immunity.

<pre>
An MC672 is a 2 input NAND.
An MC667 is a dual mono-stable multivibrator.
http://html.alldatasheet.com/html-pdf/107787/ETC/MC672/110/2/MC672.html
Those data sheet aggregator web sites suck...
</pre>

<p>
The pin-out from MC672 to 4093 is slightly different, but may be adapted.

<p>
The energy control card almost works...  The voltage comparator works, but
its sense is strange.  Is the voltage from the PD2000 card negative?  (It is.)
The NAND chip makes sense.  The transistors driving the series SCR make
sense on the schematic, but their behavior does not.  I've replaced everything
that was on the 15V rail, but not T5 and T6, since they are on the switched
15V rail, and T5 is irreplaceable.

<p>
Shopping list:
<pre>
momentary buttons  
	digikey 708-1434-ND
	manufacturer MP0045/3D0NN000
rotary switch
	digikey EG1954-ND
thin 50 ohm coax
	digikey A307-100-ND   RG174 50 ohm 0.1" diameter   100' $72
panel mount D9?   (Stock)
panel mount stereo 1/8 inch?   (Stock)
jack screws    201414-4  201413-4
M34 pin tool
	tyco number 305183  digikey A1329-ND
240V to 6V transformer, for powering CPU
	digikey MT3102-ND
SMT optocouplers, for checking 48V stuff, and inputs
	NO: socket the optocouplers
	digikey 751-1263-5-ND   $1.43 each
8 pin DIP sockets  (or 6?)
	ED3308-ND gold plated machined pin $0.84 each
watch crystals
	digikey 300-8303-ND
1K, 1.5K through hole resistors
flow sensor
	digikey 725-1070-ND
4081 quad AND, for generating SCR clock from disable
</pre>

<h2> Controls:</h2>
<ul>
<li>
CPU comes up on (un-switched) supply, and can generate the "supply" LED from
its VCC.
<li>
Circuit breaker as in current circuit, enables 48V and evaluates interlock.  
  CPU evaluates the interlock with an optocoupler, supplies interlock LED.
  (interlock is as currently implemented, CPU only inspects.)
<li>
Turn key, applies 48VAC to R1, etc.   activates everything.
now in idle state
<li>
Press charge, starts charge cycle
<li>
Ready signals from the chargers, on two separate LEDs and a single Ready LED.
in ready state   (may still top-off caps)
<li>
Press Fire: starts qswitch driver style sequencer on CPU, generates PC signal,
OSC fire, AMP fire.  back to idle state
</ul>

<p>
Q-switch is controlled by a separate CPU in the head.  (existing q-switch trigger)
Second serial port of controller CPU is connected to the q-switch controller.

<h2>Mode knob:</h2>
<ul>
<li>
  single shot
<li>
  multi-shot  (goes straight into charge state, just press fire)
<li>
  auto - several frequencies?  (will fire as quickly as possible, unless gated)
</ul>

<p>
How to control power?  By varying the voltage of course...  But what should
the user interface be?  Current opinion is that there will be multiple
configurations setup via the serial port, and selected with a rotary switch.

<p>
safe-light switch:  disables LEDs

<h2>Inputs:</h2>
<ul>
<li>
BNC to optocoupler Gate:  laser will not fire when high
<li>
BNC to optocoupler Fire:  laser will fire when high (and gate low)
<li>
1/8" stereo Fire: when tip and ring are shorted (and gate low), will fire
<li>
D9 serial port: all controls are available via serial command (though actual
power on must be done with key-switch.)
</ul>

<p>
Serial port has all the voltages reported and controllable.  

<p>
Socket the optocouplers.

<p>
voltage from the PD2000 card is /negative/.   Why?

<p>
Gave up on the transistor magic of the energy control card...  Assembled a
555 timer, NANDed that with the output from the comparator, and injected that
into the base of TR6 (through the existing resistor).  That got voltage into
the caps, for the first time.  Went up to 400V, and chickened out.  I am
currently ignoring the shunt SCR, but my current belief is that it is
activated when the desired voltage is reached.

<p>
I still don't know the optimal frequency for getting a signal through the
pulse transformer.  30 kHz makes strange noises in the charging chassis. 
I'm not sure /what/ is moving, its supposed to be solid state...


<h2>shopping list:</h2>
<pre>
panel mount fuse holders
door latches   (mcmaster-carr)
  10335A75	
6-32 flat head machine screw 1/4"
#6 flat head wood screw 1/2"
</pre>

IMAGES:20110205
<h1>20110212</h1>

<p>
Spent most of the day fabricating a box for the controller.  1/8" aluminum
and some nice hard wood left over from my microwave cart.  The aluminum
is a bit thick, but it was in stock (Kody gave it to me.).  It came out
extremely well.  

<p>
2x M34 on the back, and a D9 for the head electronics.  The head will
need RS-232, trigger, and some power. The power can't just be low voltage
due to the q-switch power supply requirements.  Might include low voltage
anyway so the CPU comes up at the same time as the controller CPU.

<p>
D9, 2x BNC, 1/8" stereo on the front, for RS-232, gate, trigger (TTL),
trigger (dry relay).

<p>
I of course don't have the right screws to mount the circuit breakers, and
no panel mount fuse holders.

<p>
I then validated some opamp circuitry.  The inverting buffer between the 
DAC and the comparator correctly inverts.  So the other inverting buffer
between the PD2000 and the ADC should be fine.  The voltage comparator was
cargo-culted so it should be fine.

IMAGES:20110212
<h1>20110219</h1>

<p>
The 5/8" drill bit I ordered did not fit in my drill press's chuck.  Blea...
So I ended up using a 9/16'ths to get close, and a round file to finish it.
The less than round hole is covered by bezel of the button.  

<p>
I then took the panel artwork to Kinko's, and laminated it.  I got two, just
in case I screwed up the first one.  Which meant I didn't.  I then cut all
the control's holes in the artwork, and epoxied the artwork to the aluminum
panel.  I had to put the circuit breakers on first, since the artwork covers
the mounting screws (so replacing them will be a nightmare...).  There was a
bit of debate regarding which glue to use, it needs to adhere to aluminum
and plastic, which IMHO eliminates standard elmer's glue.  Super glue is a
pain, and tends to fog stuff anyway.  I have no experience with contact
cement.  So epoxy it was.

<p>
Spray adhesive is extremely non-archival.  It turns yellow and starts
peeling after a couple of years.  My 315M control panel is not looking
particularly happy.

<p>
After sticking the artwork on, I cut the overhanging paper/plastic flush 
with the edge of the aluminum and then mounted all the controls.  I then
put a bead of epoxy around the edge to seal the now exposed edge of the
artwork.  If it gets wet, or perhaps someone is removing drooling epoxy
with Windex, water will wick in, and make a mess.

<p>
And then I started doing the point to point stuff for the LEDs and buttons.
Electrical work has started, Yay.  I figure finish all the low voltage stuff,
cable tie it into submission, and then do the 48V and 240V stuff, separately
bundled.  I'll probably route everything to one side, so it can hinge open.

IMAGES:20110219
<h1>20110227</h1>

<p>
Found a whole bunch of not-quite-right footprints, and corrected them. 
Missed the 1uf filter cap footprint being a bit small. I then etched the
board, and am now populating.  The 3.3V power supply functions.  To register
the two sides of the board, I lined up the two pieces of blue stuff, and
then taped three of the edges together with laser printer labels.  I then
inserted the copper-clad board into the "envelope", and ran it through 
the laminator.  The two layers lined up remarkably precisely.  I might be
able to consider my tool chain to be two layer now.  (Perhaps when the feat
is duplicated...)

<p>
I mounted the board and transformer for the 3.3V supply on the back of the
box.  Had the PCB upside down the first time, so there are a bunch of extra
holes in the back.  :-P

<p>
I don't want to put connectors on everything, its just too many points of
failure.  But that complicates testing, I don't want to assemble the second
energy control part until the first one demonstrates functionality.

IMAGES:20110227
<h1>20110228</h1>

<p>
The power supply is functioning.  I assembled a testing power supply to
avoid having to deal with the rest of the chassis for now.  There is some
weirdness trying to run both the 3.3V and +-15V rectify/regulators off
the same transformer, the 3.3V filter cap gets reversed and very hot.  I
need to tie the regulator inputs together directly.

<p>
The CPU is installed and running, talking to it with both JTAG and RS-232.
The RS-232 line driver is also installed and happy.  

<p>
So next up is straightening out the power supplies so they both operate at
the same time, and then getting the DAC chips installed and functional.  
Once that works, on to the opamp, to make sure the inverting buffer inverts.
Then 555 and and gates...

<p>
The theory is to assemble the OSC energy control subassembly completely, and
test at least charging, if not all the way to firing.  Then do the AMP 
sub assembly after the design is validated, so as to avoid installing expensive
voltage reference and DAC chips pointlessly.  However that makes the order
of assembly very non-optimal.

IMAGES:20110228
<h1>20110302</h1>

<p>
The GND plane was not complete, it ran off the edge of the board, so the big
filter cap for the 3.3V supply was not properly connected.  Until it arced.
Which incinerated the MSP430...  So I got to replace it...  no more spares.

<p>
I then placed the REF02, and the DAC.  So now I need to get the i2c code
working, to test the DAC.

IMAGES:20110302
<h1>20110305</h1>

<p>
The 555 timer runs warm.  Absolute max Vcc is 16V, and we're running at
15.5 or so.  I suspect its marginal.  I can get 18V 555's.

<h2>Shopping list:</h2>
<pre>
10K SMT  (lots)
180 SMT, TH
820 SMT, TH
MSP430s
470 pf SMT 805
gnd loop xfrmers for car stereo
</pre>

<p>
I suspect that P1.3 is fried, had issues with damaged 15V CMOS.
Bridged with P1.4.

<p>
3.3V is not sufficient to drive the 15V CMOS.  Need level conversion 
transistors.  So I did the components floating in the air thing, and
got an NPN with some 10K resistors between the MSP430 and the AND
gate.  It reversed the sense of the enable bit (not a problem, its
software) but that is a bit less optimal, in that it is enabled if the
CPU is not up, and thus does not fail safe.

<p>
So now, the series SCR driver is populated, the opamps are opamping,
the ready LED driver is populated and LEDing (but needs a GND connection,
the trace was severed by the board cropping), the ADC is happily
reporting millivolts on the voltage monitor pin (but the buffer opamp
is not calibrated), the DAC is driving the reference for the opamp,
its buffer opamp is also not calibrated, and last but not least the
charge/done opamp is generating the correct signals.

<p>
Then I assembled the back of the panel, with lots of indistinguishable
wires.  There are separate bundles for the LEDs, the controls, the
OSC, the AMP, and the 48V interlock stuff.  I have some doubts about
exactly which pins do the latching R1 closed thing on the 48V stuff.

IMAGES:20110305
<h1>20110306</h1>

<p>
Finished assembling the 240V and 48V wiring (except for the connection
to the micro-controller for observing interlock).  I then went over it
again with a continuity tester and re-verified everything.  Found an
error too, pin P ended up in pin L.

<p>
Then I Applied Power.  The 240V wiring is correct, the 48V wiring is 
also correct, the key switch properly closes R1, the dump switch 
properly opens R1.  The little transformer for the 3.3V supply works,
but there is no integration with the PC-board or amplifier chassis yet.

<p>
Now I'm assembling coax cable assemblies for going between the M35
connectors and the PCB.  Lots of gratuitous heat-shrink.

<p>
Note that there are two pin numbering schemes for M35 connectors.  The
old style has lower case letters, the newer style has double uppercase
letters, AND THEY ARE DIFFERENT.

<p>
The next step is testing the entire energy control circuit, which will
be scary.

IMAGES:20110306
<h1>20110310</h1>

<p>
Spent the last few week days assembling laborious but non-difficult
cable assemblies for the 6VAC power, 18VAC power, and coaxial lines
for SCR drivers and triggers.  

<p>
Filled out the firmware some more as well.  Rearranged the lamps code to
generate the lamp timing instead of qswitch timing.  Added read-back to the
i2c code, since if that value is written to the DAC wrong very bad things may
happen.

<p>
Assuming I don't find anything catastrophic, the caps should charge
on Saturday, and possibly even fire the lamps.  If the design is
validated, then populate all the AMP sub-assemblies and do it again.

IMAGES:20110310
<h1>20110311</h1>

<p>
The i2c read-back code works...  All the front panel LEDs are in backwards
(need to be common positive, not common negative).

IMAGES:20110311
<h1>20110312</h1>

<p>
Short answer: no joy.  No smoke either, but things seem to run warm.
(1/8 watt components may be a problem.)

<p>
The original energy control card puts a square wave across the pulse 
transformer which is 7.5V peak to peak, with the low being maybe 1V under GND.
Mine is much less amplitude.  Is the transistor in backwards?

<p>
The original transistor is 100 ohms from +15V, mine is 400 ohms from +15V,
or 150 and 37 ma respectively.

<p>
Replaced 390 ohm with 82 ohm, resulting in being 92 ohms from +15V, or 163 ma.
The amplitude is 3V peak to peak, with low being 1.2V under GND.
The cap is now charging, with no voltage calibration.  It overshoots
though.  Set it to n volts, and you get n+m volts.  

<p>
NAND is running hot, and amplitude of square wave going to SCR is still
low.

<p>
The over-voltage card has been empirically observed to function...  and opens
at about 3 kv.  Lamp min voltage is 800 V, and max voltage is about 4 kv,
according to the usual flash lamp sources.  (8 inch arc length, assume 5 mm
bore.)

<p>
The trigger circuit is completely wrong.  It just needs an NPN from +15V,
to generate an active high signal.  See energy monitor/delay card schematic,
for the thing driving OSC sync or AMP sync.

<p>
ready signal doesn't reset properly...

<p>
After correcting the trigger circuit, it charged the cap, and the lamps have
fired.  Yay, photons!

<p>
Now I'm poking at the AMP 48VAC stuff.  Its being annoying.

IMAGES:20110312
<h1>20110313</h1>

<p>
Dan suggested that the 555 was being torn up by charge current, and to use
a smaller cap.  So I substituted a 10 nf cap, and replaced the resistors
with larger values, 12K and 1.5K for the 1.5 and 270 respectively.  The 
555 is now Much Happier.  The resulting frequency was 5 kHz, and it drove
the SCRs fine.

<p>
Got the AMP interlock figured out... Finally...  So the AMPs 240VAC and
48VAC stuff is now working.  Its energy control section is still unpopulated.

<p>
Got the OSC to observe the interlock, but only across the key switch,
so it can't be observed when the laser is on.  Which is abnormal, but
matches the original controller's behavior, the light would go out when
the key was turned. 

<p>
Corrected the polarity of the panel LEDs, and hooked up the supply and
OSC ready for testing.  (worked)

<p>
Attempted to switch to on board power.  There is much weirdness.  It 
can only fire the laser when using the testing configuration.  when using
the test supply for the 3.3, and on-board for +-15, it will charge but not
fire.  And there is something about the safe-light switch which prevents the
CPU from starting (or at least getting to the CLI).

<p>
Something is consuming a lot of 3.3V.  The MSP430 should be sub 10 ma...
It seems to be the LEDs (but there are only two...  20ma each.  That is 
regulating down from more like 12VAC though so that may make sense.). 

<p>
Attempting to debug the power supply weirdness:
In debugging mode, C22 is tied to C16 and AC is applied to connector K1.
So the +3.3V is regulated down from the unregulated +-15V supply, and
bypasses its bridge rectifier.  In that state, the fire pulse looks perfect
(The amplitude, at 1.7V, is a bit low, but that is across a terminating
resistor.)  When the capacitors are disconnected, and both bridge rectifiers
are in use, all the DC voltages look right, but there is much unhappiness,
noise, and the fire pulse is taller but not square.  It goes from 0 to 1.7V
(approx) and then keeps rising at a slower rate to nearly 3V.  Why?

<p>
Are the bridge rectifying diodes on the 3.3V supply fried?


IMAGES:20110313
<h1>20110316</h1>

<p>
The 3.3V diodes are fine (brand new).  There were some poor vias causing
really nasty transients on the 3.3V lines around the CPU (fixed).

<p>
The problem is not the 3.3V supply, the crystal clock is not starting, and
the cpuInit() function will not return until it starts.  Tapping on the
crystal will generally start the clock...  (So its the usual MSP430 problem.)

<p>
Increasing the voltage into the 3.3V regulator doesn't help.  Its something
to do with the +-15V supply having to come up at the same time.  If the
3.3V is up, and the CPU is hanging, applying the 15V supply will make it
come up.

<p>
Negative voltages on analog inputs again?  I measured that, and its on the
order of -0.3 millivolts.

IMAGES:20110316
<h1>20110320</h1>

<p>
So the trick to make the clock work is to assert all the outputs first.
Then things don't float and the negative voltages don't happen.  Then get
the capacitor config correct and wait not just for the fault flag to clear
but to stay clear for 250 loops.  The clock is now starting very reliably.

<p>
Then, the trick to get the trigger circuit to work is to connect to the
collector on the PNP transistor, not the emitter.  Then the line hangs 
out at 0 volts, until the PNP goes poink and drags it up to 15V.  The
1K and 470 ohm resistors are terminating resistors for the transmission
line.  The trigger is also happy.

<p>
The interlock detection is wrong...  The optocoupler is too sensitive,
the 48VAC noise generates a false positive and it looks like the interlock
is closed when its open.  Measure relative to frame GND?  That didn't seem
to work very well with the multi-meter.  The interlock is /not/ happy... :-P

<p>
I also swapped the 390 ohm for 82 ohm resistor, so the shunt SCR driver is
now properly driving.  It didn't explode...  but didn't seem to do much
either.  The opamp still overshoots, so the ready LED never goes out.  I
haven't adjusted the gain resistor on it though.

<p>
Current theory is to bail on the interlock for now, and populate the amp
energy control.  The rework is simple enough.

IMAGES:20110320
<h1>20110325</h1>

<p>
Populated the amp energy control block, the rest of the LED drivers, the
qswitch trigger, the panel buttons, and the fire input.  

<p>
The amp charged, but there is a high voltage leak somewhere.  There is 
lots of ominous popping when it is charged.  It did fire though, so
there is light.  The amp Ready LED works too.


<h2>DAC calibration:</h2>
<p>
Initially, with RV at 5K  0xFFFF = -7.32V,  0x1E00 = -0.856 and 1E00 will
exceed the set point on the OV card.  So we will adjust, so that 0xFFFF
will get -1.0V, and that will get us more than full range.  Except that when
RV2 is at min setting, its -5V.  

<p>
So OV is at about 0x2c00  we have between 13 and 14 bits of precision.

<p>
Set the osc and amp to the same thing.  (DAC 0xFFFF = -5V)

<p>
Attempting to find/understand the HV leak in the amp:
ADC values recorded at approx 30 second intervals without head connected:
<pre>
  osc  amp
1 380  372
3 374  360
4 369  355
5 364  349
</pre>

<p>
The amp drops slightly faster than the osc.

<p>
Amp connected:
<pre>
1 384 379
2 380 372
3 377 363
4 371 360
5 366 351
6 363 344
</pre>

Amp connected, started at a higher voltage:
<pre>
1 449 432
2 443 426
3 438 416
4 433 411
5 431 404
</pre>

<p>
Need to detect dump button being pressed, to reset the state machine.

<p>
Every once in a while, the amp DAC gets out of sync, and setting the set point
fails.  It can be reset by power-cycling everything (including the 3.3V).  Which
is weird.

<p>
The Ready flags "stick" (and possibly overshoot) because of the 0.022uf cap
on the voltage sense line.  Remove it?  I kinda like the low-pass filter.  
Need to adjust the feedback on comparator, to see if that makes it happier.

<p>
If after firing, the measured voltages don't drop, report a miss-fire.

<p>
The amp DAC has quit working.  After working fine for a while.  There is much
nastiness on SDA (SCL is clean).  I replaced the pull-up resistor, no joy.
I removed the DAC, and the noise went away.  Guess I fried it while soldering.
Two spares remaining...

IMAGES:20110325
<h1>20110327</h1>

<h2>ADC calibration:</h2>
<pre>
(all numbers in decimal)
AMP:
DAC		volts	adc
1024		710	714
1280		760	763
1536		810	814
1792		860	864
2048		900	914
2304		950	967
</pre>

<p>
Max voltage for an 8 inch lamp is 3500 Volts.  ADC is 12 bits, or 4096, and
right now is resulting in almost exactly 1 volt/bit.  So we're going to
leave it there...

<pre>
(all numbers in decimal)
OSC:
DAC		volts	adc(dec)
512		620	621
768		670	678
1024		720	730
1280		780	790
1536		820	827
</pre>

<p>
The Osc is similarly almost exactly 1 volt/bit.

<p>
The function from DAC to cap volts is not linear.  It looks exponential.
The osc and the amp are very similar.  (though the above data only overlaps
at three points.)

<p>
The Osc has stopped firing.  My circuitry is OK, the signal leaving my board
and arriving at the trigger card looks fine.  After poking at things, and
comparing the signal at the gate to the big SCR on the Osc and the Amp, I
think the little SCR got fried.  I guess this project has achieved the 
wack-a-mole phase.

<H2>Shopping list:</h2>
<pre>
1K smt
replacement SCRs
rectifying diodes
</pre>

<p>
Should have added a way for the MSP to directly detect dump being pressed
as well as trigger a dump itself.  There are extra contacts on the dump
button...  Optical alignment and qswitch first I think.

IMAGES:20110327
<h1>20110328</h1>

<p>
Fun with curve fitting...  I found an example using numpy and curve-fitted
the DAC to voltage curves.  If you neglect the Y intercept (which is approx
500 volts) and assume its 0, the ratio from DAC to volts looks really weird.
But, once you get the Y intercept correct its all happy and linear.

<p>
And, below 500V, 8 inches of arc is not going to be very happy anyway.
So, the minimum voltage is the Y intercept, which is about 520V, so I'm
calling it 600.  

<p>
The horrible hack of momentarily increasing the set-point to reset the 
comparator also works.

<p>
firecomplete() gets called during the pulse, it tends to see around 350V.
It'll be down to 50V seconds later.  Do I want to delay longer and see
the <100V, or stay were I'm at and just see the drop from at least 600
down to 350?

IMAGES:20110328
<h1>20110402</h1>

<p>
Switching the trigger cards just made neither osc nor amp fire.  But the
osc will fire if you try enough times.  Found out what the issue was...
The trigger card charges a cap with the 15V signal.  When the cap voltage
exceeds 6.8V (from a zener diode) then the gate is below the anode, and
the SCR goes boink.  So, leave the 15V on long enough and it'll fire.
If the 15V drops too fast, the cap never charges and no pulse.


IMAGES:20110402
<h1>20110405</h1>

<p>
Fun with optical alignment.  I need to build another alignment stand,
to shine a laser pointer into the OC.  There is just too much loss trying
to get through the HR.  

<p>
Then, what is the threshold voltage?  According to the laser-FAQ, the 
resonant reflector of the hughs ruby range finder is 5 percent to 42 percent
depending on the angle.  ( http://www.repairfaq.org/sam/laserscl.htm )
So I need to read Solid State Laser Engineering, and ponder gains/losses
in the resonator.  There are A Lot of unknowns...

<p>
From the laser-FAQ, the hughs ruby puts out 50mJ output at 1095 VDC, 150uf
cap, arc length 3 inches rod length 3 inches by 1/4 inch diameter.
Or, threshold at 75 Joules (electric) input.  rod volume==0.1472621545 in^3
Divide by volume...  509 Joules per in^3

<p>
Osc is 250 uf 8 inch arc length (two 4 inch lamps in series) 4 inch rod 3/8"
diameter volume=.4417864635 in^3
Amp is 250 uf 8 inch arc length two lamps in parallel each with their own
cap and PFN. (so really *2 joules)

<p>
Given the osc volume is 0.4417864635 in^3, and we need 509 Joules per in^3
threshold at 224.86 Joules.  I've been testing at 900V, is barely enough
to fire the lamp (good for testing the controller though), which is 101
Joules...  way too low.  At 1400V, we get 245 Joules.
Max voltage for 8 inches of arc is 3500 Volts (EG&G catalog).  The OV card
trips at about 2500 Volts.  

<pre>
2000V = 500 Joules
2500V = 781 Joules
</pre>

IMAGES:20110405
<h1>20110409</h1>

<p>
Got coherent photons, threshold poorly aligned at V=2100.  Weirdness at 2200V,
the DAC didn't set right, rc=0x40.

<p>
I aligned the alignment laser by putting paper disks with holes on the 
OC and etalon.  The outer edge of the disk lined up with the big cylinder,
and then the laser went through a small hole in the center of the disk.
I then reflected the laser off the front of the OC back to the laser,
then did the same with the HR.  I removed the axial mode aperture,
polarizer, Qswitch, and etalon.

<p>
It then made /lots/ of photons and was extremely multi-mode.  I then 
put the mode control aperture back in, and it made more like
11 millijoules, at 2100V (about 214 joules of electricity).  I also
cleaned everything (except the rod, which is nigh-impossible to get
to), all the optics were filthy.  Even the axial mode aperture was
all blackened on the back.  So I polished it with  2000 grit sand paper
and a dremel, to get rid of the black marks.

<p>
This laser puts a whole lot more heat into the coolant than my YAG Quantel.
Ambient temp was 66 degrees F, and the coolant was 74 F when I stopped playing
with it.  (4 gallons of coolant, delta of 8 degrees F = 4.44 degrees C,
4.1 J per degree C per ml, so about 275914 Joules.  When that is divided by
551 Joules (for a 250uf cap at 2100V), its 500.7 which is remarkably round
but I can't believe I fired the laser 500 times.  This model fails to take
into account heating from the pump, which is putting about 200 watts into
the system.

<p>
TODO:   check voltage regularly and clear READY flag if it drops too low.
software flow control.  max-charge-time sanity check.  Perhaps a
specific FAULT state, which blinks ready or something?

<p>
<h2>Order of optics insertion from the manual:</h2>
<ul>
<li>OC and HR   (operate laser and maximize power)
<li>Polarizer, qswitch, mode aperture   (operate laser and maximize)
<li>etalon
</ul>

<h2>On adjusting the alignment laser:</h2>
<ul>
<li>
  There are four screws...  and everything interacts.  But its not actually
  that bad.
<li>
  First, quantify adjustments.  Watch the phillips screw head as you rotate the
  screw and count 1/4 or 1/2 turn increments.
<li>
  There are two relevant movements: translation and rotation.  Rotation is easy,
  just adjust the front or the back screws.  There will be a small translation
  though.
<li>
  To translate the laser, adjust both front and back screws the same distance.
  IE: to go straight down, screw all the screws in the same distance, to go to
  one side, screw front and back of one side in and front and back of the
  opposite side out the same distance.
<li>
  So now ponder the alignment laser, shining on a paper disk with a hole in
  the center stuck to your OC.  Rotate (just front screws) so the beam goes
  through the hole.  Where does the beam hit on the disk on the HR?  Is it spot
  above the HR's hole?  Imagine the beam pivoting on the hole of the OC disk like
  a see-saw.  If the spot is above the hole, the laser is low.  Translate up,
  (unscrew all four screws the same distance) then rotate (just front screws)
  so the beam hits the hole on the OC again.  Then recheck the spot on the HR
  disk.  It should have gone down a tad.  
<li>
  Repeat ad-nausium.
</ul>

<h2>Shopping list:</h2>
<pre>
  thin tubing for secondary cooling loop
    1/4" ID  stuff to get to garden hose fitting.
  solenoid valve
  coolant temp probe
  or little circulating pump, to put ice on the cooler.
  bigger torch
</pre>

<p>
Beware of polarization of the alignment laser.  And the laser printer
transparency stuff does /something/ to the alignment laser beam which makes it
impossible to observe the reflections off the etalon.  Use a piece of B&W film
instead.  triacetate is cast, not extruded, and does not affect polarization.

<p>
Fabricated a glass water to water heat exchanger for the cooler.  Its about
6 feet of 1/4 inch OD tubing more or less coiled up (I am a lousy glass
blower).  The theory is to siphon ice water through it as opposed to doing
something more long term, since the only time that a high repetition rate is
relevant is when aligning.

<p>
All the optics are now in, and OSC is achieving 13 mJ at 2100V, single axial
mode, unknown longitudinal mode, no qswitch.  Need a "1 mm 65%R" etalon.  The
adjustment of the etalon is very touchy, and makes an amazing difference,
right is 13mJ, wrong is 2mJ.

<h2>Pinout of the etalon TEC connector is:</h2>
<pre>
5 pin male din, numbered 1 to 5 from left to right looking into the connector,
with the tab on the bottom..
(That is not correct DIN pin numbering...)
1	green	temp sensor
2	black	frame gnd
3	red	heater
4	yellow	temp sensor
5	blue	heater
</pre>

The heater is 18 ohms total, consisting of 6 series resistors at 60 degree
intervals around the etalon.  temp sensor is between two of the resistors.

IMAGES:20110409
<h1>20110504</h1>
<p>
Fun with an aixiz LED driver for a brighter alignment laser:

<pre>
With 5.6K current resistors:
Vcc---------Voltage Out () Max Output (1mv = 1ma)
 3VDC----------2.9VDC-----------27ma
 3.5VDC--------3.1VDC-----------76ma
 4.0VDC--------3.3VDC----------144ma
 4.5VDC--------3.5VDC----------226ma
 5.0VDC--------3.6VDC----------310ma
 5.5VDC--------3.6VDC----------400ma
 6.0VDC--------3.75VDC---------430ma

With 100ohm current resistors:   (which mine has)
Vcc---------Voltage Out () Max Output (1mv = 1ma)
 3.0VDC---------2.88VDC--------22ma
 3.5VDC---------3.12VDC--------54ma
 4.0VDC---------3.17VDC--------79ma
 4.5VDC---------3.24VDC-------150ma
 5.0VDC---------3.39VDC-------222ma
 5.5VDC---------3.39VDC-------243ma
 6.0VDC---------3.40VDC-------243ma
</pre>

<p>
From
http://laserpointerforums.com/f67/making-your-aixiz-driver-work-solution-56733.html

<p>
My 200mw laser diode thresholds at 80ma, and wants 210ma at 2.5V for 160mW
of output.  So feed it 4.5V, and see what happens...  

IMAGES:20110504
<h1>20110508</h1>

<p>
The laser diode is getting about 2.2V after the regulator (getting 4.5V
from 3 AA's).  I turned the current limit up till it stopped getting brighter
then backed off a bit.  

<p>
Firmware fix: if the observed cap voltage drops too far, go back to idle or
something...

<p>
Re-assess maxdac (0x2000), amp only goes up to 2000V, need 2100 to 2500.

<p>
I put an aluminum foil pin hole on the 200mw laser diode, and put it behind
the HR.  It can just barely get a useful number of photons through the HR.
The optical lever arm is probably too short to align the HR itself with,
but the alignment from the front is still valid.  I then aligned the laser
diode with the paper disks on the etalon and OC.  The laser diode spot is
relatively easy to see until the spatial filter.

<p>
I aligned the amp by putting the paper disks on the spatial filter mounts and
aligning with them.  I then did the fog-the-end-of-the-rod trick and observed
the spot on the ends of the amp rod.  So the amp is finally aligned.

<p>
I then put the spatial filter lens in, and aligned its output with the
paper disk on the pinhole mount.  I then put the pinhole in, and aligned
it with the laser diode.  Then I put the joule-meter after the pinhole,
and fired the real laser, tweaking the pinhole positions to maximize the
joule-meter reading.

<p>
At osc=2100V amp=2000V, got 122 millijoules after the amp.  Don't entirely
trust spatial filter alignment, and voltage is low.  the amp will not 
go above 2000V, due to the current value of maxdac.  Inch it up a bit, but
avoid the over-voltage interlock.

<p>
Need coolant temp monitoring, and possibly thermostatic control of primary
coolant loop.  The secondary coolant loop will cool the primary coolant pretty
well, but goes through ice rather quickly.

IMAGES:20110508
<h1>20110511</h1>

<h2>Fun with the qswitch driver:</h2>
<p>
The current theory is that the lumonics circuitry has SCR stacks which
generate large negative going pulses.  There is then an inductor which
does something, and its capacitively coupled to the pockel cell.  Since its
capacitively coupled, the pockel cell sees a square pulse.

<p>
Two of these pulses are generated, such that they cover the entire lamp
flash, and have a gap between them.  

<p>
So, we need two trigger pulses, for two avalanche transistor stacks,
possibly microseconds apart, but with a relative position precision in
nanoseconds.

<p>
So, we use two of the MSP430 timer outputs...  and put a DS1123 delay chip
on one of them.  It will delay from 0 to 255 steps, at 1 ns/step.  So
for delays of less than 125 ns, we set the two msp430 outputs to the same
time, and then add delay.  For >125ns, set one to clock n, one to clock
n+1, and then add the remainder with the delay chip.

IMAGES:20110511
<h1>20110619</h1>

<p>
The D9 on the qswitch control card is backwards,  pin 1 is where pin 5
should be.  The photo diodes are also backwards, should not have been flipped,
but the pins are sufficiently flexible.

<p>
And of course the clock doesn't want to start.

IMAGES:20110619
<h1>20110622</h1>

<p>
The photo-diode inputs moved between versions 1 and 2, so I added a pile of
macros to move the software around, but I forgot to use the macros in the
init function.  So, I chased what I thought was a hardware problem for at
least an hour before realizing it was software.  :-P

<p>
The clock starts now, the problem was insufficient solder on the pads,
so it looked soldered but was actually open.  The two photo-diode inputs
also now work.  The RS-232 is happy, and talking to the computer through
the controller.  The delay chip is not installed yet, and none of the
software for the accopian DAC is present.

<p>
Getting the optical fiber into the amplifier is easy, the hole in the
cover is large enough for it to easily get close enough to the end of the
rod without blocking the beam.  The oscillator is more difficult.  The
axial mode aperture blocks one end, and the polarizer blocks the other.
Fish it though the bottom with the power lines?  Then it needs a rather
sharp bend.  Drill a hole in the end piece?  Probably, but I will need to
work up the enthusiasm to extract that part, and hopefully not un-align 
the OC.

IMAGES:20110622
<h1>20110624</h1>

<p>
osc and amp offset to 0x200 clocks.  
Assembled qswitch driver, taped optical fiber to ends of the flash lamps,
and defeated interlocks so the cover doesn't get in the way.

<p>
The RS-232 driver on the controller needed to be re-flowed.  Its amazing
how things work for a while, then spontaneously quit.

<p>
Got first light into the qswitch trigger.


<pre>
firecomplete

decision at 0xd324  val= 0x8287
min= 0xd044  max= 0xd466  delta= 0x422 134 usec
lamp 0  0x0 0xd031  len 6777 usec
lamp 1  0xd243 0xe586  len 627 usec
lamp 2  0xd466 0xdd5d  len 291 usec
lamp 3  0x0 0x0  len 0 usec
Qswitch missfire

Voltage: 14996 Vdc
Current: 14.996 ma
temp: 300 K
&buff= 0x970
</pre>

<p>
The thing labeled lamp 0 is really the trigger out from the controller.


IMAGES:20110624
<h1>20111022</h1>

<p>
Moved the interlock measurement to the key switch, and put a 10K
resistor across it.  The problem is that the 48VAC lines waggle
around enough that the optocoupler can get a signal from the capacitive
load.  The 10K resistor shorts that out, without letting enough
current flow to close the relay.  The only problem is that when the
+-15VDC is on, the interlock gets a false open indication.  If the
power is on, then the indication is false.  Unfortunately the 
micro-controller can't read the state of the +-15VDC power directly.
But, the DACs on the energy control modules are powered by the +-15VDC,
so if we don't get an i2c error, then the power is on.

<p>
MEH...  Fixes in version 2: micro controller can read the power state
directly, AND add a relay so software can break the interlock.

IMAGES:20111022
<h1>20111023</h1>

<p>
The voltage monitoring for the AMP quit working.  It would charge, but
not get any indication that there was a charge, so would never say STOP,
and would hit the over-voltage interlock.  Which definitely validates the
design of having the separate over-voltage interlock board.  So I poked at
it, and then it started working again.  Blea.


IMAGES:20111023
<h1>20111029 </h1>

<p>
Lots of looking for the flaky solder joint...  Might have found it.

<pre>
decision at 0x2fe3  val= 0x8583
min= 0x2d03  max= 0x3314  delta= 0x611 197 usec
lamp 0  0x2fc3 0x4130  len 567 usec
lamp 1  0x3314 0x3c68  len 303 usec
lamp 2  0x2d03 0x5c0a  len 1530 usec
lamp 3  0x0 0x0  len 0 usec
Qswitch missfire
</pre>

lamp 2 is qswitch signal from main CPU.  Why is it so long?
lamp 1 is OSC

<pre>
decision at 0x5bfc  val= 0x8583
min= 0x591c  max= 0x6afd  delta= 0x11e1 581 usec
lamp 0  0x5b9b 0x6d57  len 577 usec
lamp 1  0x6afd 0x6b85  len 17 usec
lamp 2  0x58fc 0x8801  len 1530 usec
lamp 3  0x0 0x0  len 0 usec
Qswitch missfire
</pre>

<p>
The qswitch pulse is very long because the lamp trigger signals charge
a capacitor, which dumps a small SCR, which dumps a bigger SCR, which
ionizes the lamp.  A short pulse will not set it off, and the qswitch
pulse code got the same treatment.  So I moved it, the qswitch pulse
should be very short now.  I also suspect that the lamp 1 input is not
happy.

IMAGES:20111029 
<h1>20111030</h1>

<h2>Fun with the qswitch trigger, cont.</h2>

<p>
The trigger sometimes gets wonky if you play with testfire too much.
I lengthened ENDOFFSET to 17000 clocks to address it.  It may not have.
I had previously shortened the qswitch pulse to 4 usec, to have a
nice crisp pulse.  But then the qswitch msp430 didn't have enough time
to grab the rising edge, and thus missed the falling edge.  So I put it
back to ENDOFFSET like the rest.  That results in a 1700 usec pulse.  

<p>
There was also lots of RF interference in the qswitch board due to the
HV trigger for the lamps.  It can't sit on the capacitor cabinet, it 
must be several inches away, then everything is fine.  So I have it
sitting on a cardboard box beside the optical rail for now.

<p>
There is some weirdness where the lamps seem to be on longer when the
optical fiber is closer to the lamp.  So take the durations with a
grain of salt for now.  

<p>
Three shots with the OSC only:
timing is 12 usec delay for qswitch, 13 usec for osc and amp.

<pre>
decision at 0x137  val= 0x93
min= 0xfe57  max= 0x7a  delta= 0x223 69 usec
lamp 0  0x7a 0x185f  len 777 usec
lamp 1  0x0 0x0  len 0 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0xfe57 0x351d  len 1782 usec
Qswitch missfire

decision at 0x8b2b  val= 0x95
min= 0x884b  max= 0x8a69  delta= 0x21e 68 usec
lamp 0  0x8a69 0xa236  len 774 usec
lamp 1  0x0 0x0  len 0 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0x884b 0xbf0d  len 1782 usec
Qswitch missfire

decision at 0x8481  val= 0x97
min= 0x81a1  max= 0x83c1  delta= 0x220 69 usec
lamp 0  0x83c1 0x9b87  len 773 usec
lamp 1  0x0 0x0  len 0 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0x81a1 0xb864  len 1782 usec
Qswitch missfire
</pre>

Three shots with OSC and AMP:

<pre>
decision at 0x98ef  val= 0x9b
min= 0x960f  max= 0x9819  delta= 0x20a 66 usec
lamp 0  0x9819 0xb060  len 790 usec
lamp 1  0x979d 0xc458  len 1456 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0x960f 0xccd2  len 1782 usec
Qswitch missfire

decision at 0x9f32  val= 0x9d
min= 0x9c52  max= 0x9e53  delta= 0x201 65 usec
lamp 0  0x9e53 0xb698  len 790 usec
lamp 1  0x9de6 0xcabf  len 1459 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0x9c52 0xd314  len 1782 usec
Qswitch missfire

decision at 0xaf16  val= 0x9f
min= 0xac36  max= 0xae40  delta= 0x20a 66 usec
lamp 0  0xae40 0xc689  len 790 usec
lamp 1  0xadce 0xdae8  len 1468 usec
lamp 2 0x0 0x0  len 0 usec
lamp 3  0xac36 0xe2fb  len 1782 usec
Qswitch missfire
</pre>

IMAGES:20111030
<h1>20111106</h1>

<p>
Mounting holes for the qswitch driver board:
board is 4x6 inches,  mounting holes are 1/8 inches in on the sides,
1/8 inches in on the top (away from the avalanche transistors), and
1 inch in on the bottom.  That puts a HV line kinda close to one,
but not actually touching.  

<p>
The transistor sockets are epsilon too close.  A trivial quantity of filing
(per socket...) enables them to fit.

IMAGES:20111106
<h1>20111113</h1>

<p>
Trigger pulse, into the base of the bottom transistor is 5V tall, and
8.1 usec long.

<p>
250 volts across the bottom transistor (a 2N5551, its good for it).

<p>
At 118 V across the transistor, still no switching.  1937V across the
stack.

IMAGES:20111113
<h1>20111119</h1>

<p>
The diode on the bottom of the avalanche transistor stack is a 1N4734 zener
diode, 5.6V 45ma 1W.  A standard diode will not work.

<p>
So what happens is the trigger puts approx 5V from base to GND.  There
is a voltage fall from the base to the emitter, and then a reverse biased
zener, which doesn't do anything until the zener voltage is crossed, then
it avalanche conducts and a very sharp pulse is put from base to emitter.
The bottom transistor then conducts, and adds its approx 180V to the 180V
across the next transistor up.  Then /it/ avalanche conducts, and now
180+180+180 volts are across the next transistor up (repeat up the stack,
gaining voltage as you go).

<p>
It worked... Once.  The pulse was short though.  The OSC pump light is
about 1500 usec long (assuming the trigger board is right, the photo-diode
might have a long recovery time), need to be able to cover that length of
time with the qswitch pulse.

<p>
Now its prematurely avalanching, and way too low of a voltage.  The
zener diode I currently have installed is under-sized, 300mw instead of 1W.  
Perhaps it fried.  It did work, with everything assembled, exactly once...

<p>
I replaced the power in cable with a 4 conductor one, so now neutral is 
available for the 120V pumps.  The only 4 conductor cable Lowes has is 
10 gauge.  Its pretty monstrous, but matches my extension cord so things
are consistent.  Its slightly weird to be plugging 15A devices into a
30A cable (which is on a 20A breaker...), but the controller does have a whole
heap of 13.5A breakers, so I believe it is to code, or at least safe.

<p>
The power break-out is now a set of four terminal strips mounted on a 
plexiglas panel (with a cover).  Its much easier to poke at than the 
original little junction box full of split nuts.

IMAGES:20111119
<h1>20111121</h1>

<p>
I checked all the transistors on the qswitch driver with my meter's hfe mode.
Pretty much every transistor is fried.  I suspect the inductor rang, and FOOM.
Or the zener diode on the bottom fried...

<p>
I ordered the proper 5kv accopian power supply.  Next steps are probably to 
finish populating and implementing its control circuitry.

IMAGES:20111121
<h1>20111124</h1>

<p>
Replaced all the fried transistors.  Disconnected the 100 ohm resistor
(ie: everything after the avalanche string).  Its now triggering more
or less happily.  Voltage in is 2960V, voltage at top of stack is 1830V,
pulse gets down to 17V.  The low voltage varies, I'm interpreting it
as not all the transistors avalanching.  It will be interesting when
the 5kv supply arrives.  Then sometimes just one transistor starts 
self-avalanching (but not setting off the whole string) and one gets a
saw-tooth overlaid on the expected waveform.

<p>
2M resistor is hot  117 deg F...  the transistors are also warm, 87 deg F.

<p>
Added some code to the qswitch trigger to repeatedly fire at about 1 Hz.
Burning the transistors in seems to make it more consistent.  Vmin for
triggering at all is about 1430 volts across the stack  (1971V in).

IMAGES:20111124
<h1>20111125</h1>

<p>
Measured the Hfe of all the transistors.  Q1 is a 2n5551, the rest are
2n3904.  An unmolested 2n3904 is 172.  An unmolested 2n5551 is 202.
(sample size of 1, but plausible from the datasheet)

<pre>
1 189   (2n5551, trigger)
2 166
3 176
4 180
5 165
6 170
7 164
8 187
9 160
10 170
11 170
12 154   <-- replaced new one is 165
13 170
14 159   <-- replaced new one is 180
</pre>

<p>
To test HV diodes, put a 9V in series with the meter, and measure volts.
One must exceed the voltage drop to get the diode to conduct...  on a NTE517
diode, its about 3V.  So when the diode conducts, the meter will read
6V.  When the diode does not conduct, the apparatus will do a weird
relaxation oscillator thing, going from 0 to about 2V and then dropping
back to 0.  

<h2>The UV LED used to cure optical cement is:</h2>
<pre>
Mouser PN 897-lz100U600
Manufacturer LZ1-00U600  LEDEngine
</pre>

<p>
Reconnected 100 ohm resistor to the rest of the circuitry.  Inductor is still
disconnected.  The output of the first cap hangs out at 0.  When the
transistors fire it drops to -1800 volts, and then returns to 0 in about
42 usec.  Scope reports the pulse to be 14 usec, I suspect its using the 
RMS definition.

<p>
Connected the inductor...  Its now doing -130V, and a 3.2 usec pulse which
looks all nasty, like the transistors are self-avalanching again.  

<p>
Started replacing 2n3904's with 2n5551's, from Q14.
<pre>
Q14 was 180, is 180
Q13 was 170 is 1040  (fried)
Q12 was 154 is 7   (fried)
Q11 was 170 is 142
Q10 2680  (fried)
Q9  29  (fried)
Q8  off scale high (very fried)
Q7 138
Q6 101
</pre>

<p>
Much happier with some 2n5551's on the high end.  

<p>
With more 2n5551's will not trigger.  I suspect insufficient voltage across
the individual transistors to avalanche.

IMAGES:20111125
<h1>20111217</h1>

<p>
I got the accopian power supply, and integrated all the software for 
controlling it.  The inhibit input works, but takes hundreds of milliseconds
to stabilize, so its not sufficient as a rising edge for the qswitch pulse.
The avalanche stack is happy at 3700 volts (2830 after the 2M resistor)
with the first four transistors above the triggered one being 2n3904's and
the rest 2n5551's.  

<p>
The avalanche pulse is 2830 volts to 250 volts in 6 ns.

<p>
So the current question is how to get the 0 to 3000 volt step, then hold it
for on the order of 3 milliseconds of ruby fluorescence.

<p>
Stiffer i2c pull-up resistors seem to be indicated.  Went for 4.7K, based on
some random web pages.

<p>
The end of one of the big caps is arcing to the HV line going past it.  I
applied electrical tape to the trace.

IMAGES:20111217
<h1>20111229</h1>

<p>
Got a new idea...  leave the avalanche stack shorted, to hold the power 
supply down.  Then at the first lamp edge, let go so it pops up to +V.
Then at the time of the trigger, short it again.  

<p>
But, it doesn't work.  The avalanche stack drags the power supply down,
but then the voltage across the transistors is too low and they go out
of avalanche mode.  The trigger transistor at the bottom stays on (so
you see a 200V delta) but the rest go back to non-conducting.  The final
output is +V-200V,  up to +V, and then a proper avalanche switch down to
a couple hundred volts, with the usual exponential climb back up to 
+V-200V.

<p>
So plan letter-plus-one is 4000V mosfets (IXTV03N400S) to apply the high
voltage, and then the avalanche transistor stack (crowbar) to turn it off.
Go for 2 in series, to handle the 5000V power supply max.  Plan A is to
have the MOSFETS on the low-side and crowbar the power supply.  The fact
that there are two complicates that, only one can be at GND potential 
with the MSP430.  Can the MOSFET gates be driven by an optocoupler in
photo-voltaic mode?

<h2>Shopping List</h2>
<pre>
A PVI5080NSPBF is designed to drive a MOSFET gate... but is only rated for
4000Vrms isolation.  $5

A VHS1-S12-S12-SIP is an isolated 12V supply.  6000V isolation.  $10

An OPI1264A optocoupler is good for 10000Vrms.  $2
</pre>

IMAGES:20111229
<h1>20120108</h1>

<p>
The MOSFET crowbar scheme works.  With a but...

<p>
I put the MOSFETs on the low side, to crowbar the power supply. 
I generated the gate current with
photo-voltaic optocouplers (apv1122a).  Then drove the optocouplers with 
a PNP transistor on the high side, to be compatible with the drivers
on the rest of the outputs.  (They are unfortunately broken as
designed, and will be replaced in the next revision.)

<p>
So now the problem is that the 2M current regulator resistor is
overheating.  Its
dumping 12.5W of energy when crowbarred, and rated for 1.  And I
forgot the 100 ohm current limiting resistor on the avalanche stack.
(5000V across 100 ohms is 50A)

<p>
What is the RC time of 2M and 12 pf?  Rise time after the avalanche
pulse seems slow (70 usec?).


<p>
And then there are the ovens which the OC and etalon are in.  They
have an 18 ohm resistor for heating, and something which I believe
is a type K thermocouple for the sensor.  A MAX31855 is the amp
and ADC all stuck into a single chip.

<p>
MAX6682 is similar, only for thermistors.  It puts out 10 bits of
data, and a sign bit.

<p>
It is not a thermocouple.  If it were a thermocouple, it would have
a voltage across it.  Except it would be in microvolts, and my 
meter doesn't go down that far.  So I'm going to point at its
resistance, its 108.6 ohms at a room temperature of about 67 degrees F.
I believe a thermocouple would be much lower resistance.

IMAGES:20120108
<h1>20120113</h1>

<p>
So after pondering the ovens for the etalon and OC, I was thinking
the ruby needs a similar thing, or at least a temp sensor.  Possibly
the amp too.

<p>
And perhaps the interlock loop should go through the head, such
that a temperature excursion could break it.

IMAGES:20120113
<h1>20120114</h1>

<p>
How much power into the oven heater?  Lets just call it 2W for now.
We have a 24V bus, for the accopian power supply.  at 24W, 2W is 
84 mA, so the current limiting resistor is 285 ohms.  Subtract the
18 ohms which is already there?  

IMAGES:20120114
<h1>20120118</h1>

<p>
I rearranged the HV stuff so that the MOSFETS just switch the HV
instead of crowbaring the power supply.  Its switch-on time is
about 12 milliseconds.  So the controller needs to provide a
fire signal at least 12 milliseconds early.  Thats awfully long,
the 8 MHz clock rolls over at about 8 milliseconds.  The
switch-off time is sub 0.1 millisecond...

<p>
So the plan is to go back to the crowbar arrangement.  Ten 20M
resistors in parallel will be able to handle 25W of power (12W
expected).  (5000v * 0.002A == 10W)  They cost $3.89 each 
(quantity 10).  MEH...

IMAGES:20120118
<h1>20120121</h1>

<h2>Fun with PCBs...  </h2>
<p>
I modified the foo2lava filter which drives my printer so that black pixels
are converted to all four toner pixels.  That increased the amount of toner
and made the toner transfer slightly happier.  There are still lots of
dropouts.

<p>
Aligning the two layers with a light table, and then taping them together
to form a thing like an envelope works OK.  Then insert the PCB into the 
envelope, put the whole assembly in a folded piece of paper, and then
run it through the laminator.  The folded piece of paper seems to reduce
the rollers pulling on the blue stuff, so it doesn't get moved, and seems
better aligned.

<p>
Six passes seems to smudge it, such that lines between traces get filled.
Yet six passes will still not fill in all the dropouts.  Does the paper
insulate it too much?  Does it reduce the pressure?  Or increase it, due
to additional thickness?  The thinner PCB stock seems to work better,
but I typically ran two pieces through, to increase the thickness/pressure.

<p>
The thin stuff is 2/64'th thick, the thick stuff is 3/64's.  Two pieces 
of thin stuff would thus be thicker than the thick stuff, so my pressure
is low.  The single sided PCB used for the HV boards is 6/64's thick.  

<p>
So double the thick stuff, and only 4 passes?
double the thick stuff didn't fit...  4 passes.  Some wide spaces had no
problems, some narrow spaces had the blue stuff bend down and fill it.

<p>
Took the laminator apart again, removed the top "cooling plate", so it
would not block the boards, and cranked a variable resistor to the end
stop.  The temp, before I adjusted it, was maybe 260, after was 310 or
so.  Apparently best practices is 350.  I was measuring the temp with
one of those infrared thermometers, so the measurement may be low because
of the field of view of the sensor (it effectively averages over its 
whole field of view).

<p>
Second board:  holder, black only, thick 2 sided, 4 passes.

<p>
Got the color thing working.  So all four colors of toner are applied.
This causes the artwork to look soft.  And lots of stuff between the 
traces.

<p>
Third board:  no holder, all colors, thick 2 sided PCB, 2 passes.

<p>
stuff between the traces can not be removed with packing tape.  While it 
does pull off "loose" stuff, the blue stuff between traces is lower than
the stuff on top of the toner, so it doesn't get suck to.  Abrasives are
similarly ineffective.  (eraser, scrunge, brush)

<p>
Fourth board:  on thin stuff, not doubled, black only, 3 passes.  

<p>
The blue stuff starts warping after multiple passes.  Fourth board was very
spotty, but didn't have as much junk between the traces.  There seems to
be two cases of stuff between traces: there are stripes parallel to the
paper motion in the printer from the toner going onto the blue stuff unevenly.  
Then there is if a space is exactly the right width a narrow strip down the
middle.

<p>
There is a general blotchiness which matches a texture in the blue stuff
from how it was coated.  You can see droplets in its density.

IMAGES:20120121
<h1>20120127</h1>

<p>
I've been playing with a plotter, and random pens.  The trick is to find a
pen with permanent ink and a sufficiently fine point.  

<h2>From the web:</H2>
<pre>
Staedtler permanent special F number 319?
staedtler lomocolor 313 red?    <--  two votes for this one
  they make actual plotter pens too:  31HP03K-2
black medium 317 ?
micropigma pens with staedlter ink?
technical pens with thinned fingernail polish?
</pre>

<p>
Bug zapper and aquarium lamps can be used to expose photo resist.  Two bulbs
6 inches away, about 12 minutes?

IMAGES:20120127
<h1>20120209</h1>
<p>
Current theory is that a faber-castell extra super fine is narrow enough
for QFP pins (claims 0.01mm, I'd believe 0.1).  Its waterproof when it dries,
but may be smudged.  I haven't tried it in etchant yet.  The biggest problem
is the pen gets bumped in the pen holder, and shifts 20 mils or so, spoiling
the details.  I need to build a new pen adaptor
with a larger diameter ring around its body.

(20120409: Turns out that the etchant knocked the faber-castell ink's socks
off in seconds...  Only sharpie ink could deal with it.)


IMAGES:20120209
<h1>20120211</h1>

<h2>Fun with the qswitch and stuff controller:</h2>

<p>
Pins 9 and 10 are reversed on the accopian connector.
Resistor between msp430 and inhibit transistor needs to be 1K (or smaller?),
it has to overcome the 10K to 3.3V pull-up.

<h2>Fun with the heaters:</h2>

<p>
at 68 degrees, the sensor is 108.5 ohms.

<p>
Increased to 108.7 after several minutes of 24V in series with a 100 ohm 
10W resistor, which was at 165 degrees.  
Bypassed the current limiting resistor (all of them).  Got to 109.2 ohms
in seconds.  Which made no difference to the ADC.  (reads 1252 units.)

<p>
I suspect the 108 to 109 ohms with Rext=10K is below the resolution of
the ADC.

<p>
resistor change...   10K to 1500 ohm.
<pre>
66 1162
78 1158
90 1156  115.7   ohms
</pre>

<p>
Values are always even, I suspect SPI code is shifting one too far.
Poll code also isn't working right, the timestamp is not inited correctly.
<p>
Values are also way too far apart, the thermistor resistance range is
too small for a 1500 ohm Rext, but any lower and it exceeds the current
load that the ADC voltage ref can handle  (1 ma).
<p>
Measurement of 24V rail is pegged.  change voltage divider to make output
less than 1.5V.  measurement of 3.3V rail is also pegged...  :-P
<p>
Measurement of the output voltage:  set for 5000, reading 4156v, actual is
4140v with the HV probe.  I suspect the 10K on the output of the DAC is
forming a voltage divider with the circuitry in the accopian supply,
and reducing the 5V control voltage.  Disconnected, Vout is 5V, with the
accopian connected its 3.8V.  Replace 10K resistors with 1500 ohm resistors.
The load resistance is 1500+31666 ohms (according to that 3.8V drop), so
within the 2K test load from the DAC data sheet.  

IMAGES:20120211
<h1>20120213</h1>
<p>
The always even value was a bug.

<pre>
code 581  65 degrees   (beginning, so temp at sensor is 65 deg F)
code 579  75 degrees   (measured with IR thermometer on outside surface)
code 580  83 degrees
</pre>
<p>
Internal temp is much higher...  Al collar is more like 93 degrees (at
83 deg point.)  The power supply seems to push the temp reading slightly.


IMAGES:20120213
<h1>20120214</h1>
<p>
OK, screw the original sensors...  Replace them with 10K NTP thermistors.
<p>
Of course that means disassembling aligned optics.  :-P Strangely, the
alignment of the OC survived the operation.  The etalon also got back
in, but the power seems reduced.
<p>
There is an open somewhere in flash-lamp input 0, and a lose connection in 
the thermistor input such that it only operates when the card is upside down.

IMAGES:20120214
<h1>20120225</h1>
<p>
Found the opens...
<p>
Assembled a bunch of boxen, to mount the qswitch trigger and driver in.
<p>
There is a failure mode where if the PWM value for the heater is updated
at exactly the wrong time, it never resets, and fails on.  Time to read
the datasheet again.
<p>
The two photo-diodes are working.  The thermal control hardware is working,
but the software is weak.  The accopian supply control is working.  The
AC power control is working.

IMAGES:20120225
<h1>20120226</h1>

<h2>Thermistor calibration:</h2>

room temps are kelvin - 273.

<pre>
room	DAC
20	209
21	215
22	222
23	230
24	238
25	246
26	253
27	262
28	269
29	277
30	284
31	292
32	300
33	307
34	314
35	321
36	327
37	335
38	342
39	349
40	356

42	369
(and now going down...)
42	370
38	342
36	329
35	321
33	308
29	278
27	264
26	256
</pre>

<p>
And then I broke my good thermometer, when it rolled off the table as I 
was disassembling the calibration apparatus.  :-(  You can't buy proper
mercury thermometers anymore.

IMAGES:20120226
<h1>20120303</h1>
<p>
Finished assembly of the new qswitch driver board.  It more or less works,
but the current limiting resistors overheat.  They get to about 200 deg F.
5000v at 2.5ma is 12.5 watts.  There are 10 resistors in parallel each rated
at 2.5W.  It shouldn't even be breaking a sweat.  Pondering the datasheet,
the resistors are Ohmite part number SM108032005FE, which is coated with
silicone, and rated to 110 degrees C, or 230 degrees F, or 180 degrees C
(356 degrees F).  The datasheet is ambiguous, one section says the series
is rated to 230F, and another says silicone coated is rated to 356F.  So
they are either right on the edge of spec, or within spec, but I think
the real issue is getting 12.5W out of the enclosure.

<p>
The TNC connector on the qswitch is not a normal size TNC connector.  The
center pin is normal, but the threads are smaller diameter.  So I kludged it.
A Mini-UHF connector is closer, but the connector's knurled part hits the
bottom before the middle of the connector is completely seated.

<p>
The amp photo-diode doesn't seem to be reading right.  Its way too short,
903 usec instead of the osc's 2355 usec.  

<p>
Switching the fibers on the inputs, the osc was 2355 now its 773, and the
amp which was 903 is now 3518.  An old observation is that the photo-diodes
are sensitive to amplitude of the light, and perceive a brighter pulse as
longer.

<p>
Dan suggested putting both diodes into the same light source, and comparing
their measurements.  Do they both see the rise at the same time but one
is truncated?  Thats what the timestamps would indicate...  Or are they
both centered, but one sees the rise later and the fall earlier?

<h2>First q-switched shot:   (osc only, though amp is firing)</h2>

<pre>
decision at 0x9beb  val= 0x8b81min= 0x950b  max= 0x96c7  delta= 0x1bc 56 usec
lamp 0  0x96a6 0xdee1  len 2351 usec
lamp 1  0x96c7 0xb26a  len 899 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0x950b 0xdb65  len 2290 usec
Qswitch target 0xdb66 actual 0xdb66 2237 usec
</pre>

<p>
lamp 0 is osc, lamp 1 is amp, lamp 3 is timing signal from the main controller.
The delta is pretty much always 56 usec, so the expected jitter from the 
3.3V to 12V driver having to charge a cap may be too small to measure.

IMAGES:20120303
<h1>20120304</h1>

<p>
I implemented Dan's idea, and put optical fiber in each photo-diode then taped
the other ends together and illuminated them both with a camera flash.  The
observation, with both timestamps and oscilloscope, is that the leading edge
of the pulse is always right on, but the trailing edge comes earlier if
the light is attenuated.  (tested by putting my finger over one of the
optical fibers, I am not especially opaque...)

<p>
See both_photodiodes_same_light.hpgl

<p>
So then I got my det10a photo-diode (Thor labs), as a ground truth.  The rising
edges are pretty much exactly right.  The problem is the light pulse is /much/
shorter than observed electrical pulse.  The falling edges are pretty much
2000 usec late.  The electrical pulse is 10 to 20 times longer than the light.

<p>
See both_photodiodes_same_light_anddet10a.hpgl

<pre>
decision at 0x1b0e  val= 0x8380min= 0x142e  max= 0x1473  delta= 0x45 8 usec
lamp 0  0x142e 0x6b40  len 2834 usec
lamp 1  0x1473 0x615e  len 2503 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0x0 0x0  len 0 usec
Qswitch missfire
</pre>

IMAGES:20120304
<h1>20120317</h1>

<h2>Pondering the photo-diode problem...</h2>
<p>
The bottom of the diode is pulled down with a 4.7K resistor to GND.  The 
top of the diode has a 220K resistor to +12V, and a 0.1uf cap to GND.  So
when the diode conducts, it dumps the cap into the 4.7K resistor.  When it
ceases to conduct, the bottom of the diode should be pulled back down to
GND by the 4.7K resistor.  But it isn't.  

<p>
The bottom of the photo-diode is monitored by an opamp.  So it should be a
very high impedance (with a 4.7K resistor across it).


IMAGES:20120317
<h1>20120322</h1>

<h2>Fun with osc lamp timing...</h2>
<p>
See osclamps.hpgl.   The lamp pulse, as observed with the det10 sensor is
about 700 usec long.  The photo-diode output looks about the same, about
700 usec long.  The opamp output is stretched, to 1260 usec.  Why?
<p>
The amp pulse is the same approx 700 usec long.  
<p>
The opamps report 1241 usec long, 359 usec long.  One is stretched and one
is compressed.  I trust the rising edges right now though...
<p>
And the fire pulses are still not reliable.  I suspect the transistor drivers
suck...  It has the voltage gain, but not current gain, and how much can the
MSP430 sink?


IMAGES:20120322
<h1>20120324</h1>

<p>
Current draw of the head electronics box is about 0.67A (120V).  Thats
with both heaters and HV supply running.  Coolant pump is 1.6A.  So
if the head electronics are plugged in with the cooler is 2.27A,
over wire which is probably too thin (18 or 20 gauge, came from a
hamfest...), but was not noticeably warming.

<p>
Corrected the power supply voltage monitoring ratios.  The 3.3V rail
is more like 3.5V...  Which may be why the msp430 is running warm
(312K), though its also directly above a 24V switching supply.

<p>
The thermal control works, but every once in a while a max6682 chip
seems to crash.  It starts reporting just 0.  A power cycle gets it
sane again.  The cover is currently off, hopefully better RF shielding
from the flash lamps will improve things.

<p>
Started tweaking the optical alignment.  Before doing much, OSC 
is 10 mJ/pulse free-running.  After tweaking the OC and HR a bit...
OSC is 16 mJ/pulse free running at V=2100.

<p>
Pondering everything_20120424.hpgl...
The top trace is the voltage on the qswitch.  
Middle is output from the photo-diode.
Bottom is light from the DET10, observing a post-it of the laser
output.

<p>
Observe how the qswitch isn't stopping the laser from lasing.  (qswitch is on
driver 1, driver 0 is the MOSFET... need to clean up that code.) I think the
qswitch will need to be realigned from scratch.  Blea...  I managed to get a
diffuser polarizer and screen into the resonator, its definitely off.  The
alignment laser happens to be polarized, which simplified things a bit.

<p>
And why isn't the rising edge of the qswitch waveform on the qswitch trigger
in from the main CPU?  The signal is arriving a good 70 usec before
everything...  It needs about 100 usec to get to 5kv.  (timing defaults on the
controller recomputed...) Why are there multiple peaks on the DET10?  They
don't "feel" like the laser doing the relaxation oscillation thing, too
randomly spaced.

<p>
I need a better heat-sink, things get weird when the coolant hits 77 degrees F.
The osc is about 1000J, the amp is 2000J.  So 3000J/shot of thermal load,
into 3 gallons of water.  1J increases the entire thermal mass's temp by 
.0000213949 degree K (or C...).  So one shot should be 0.064 degrees C,
or 0.10 degrees F.  I'm seeing a rise from 72 to 77 degrees in far less
than 50 shots...  The circulating pump is a not insignificant load, the
temp will go up with just the pump running.  If we call the pump a 100%
efficient heater, then its putting 200W into the coolant.

<h1>20120403</h1>

<h2>Talked to Ed Wesley...</h2>

<p>
My laser apparently came out of a holocopier.  

<p>
Lase off the etalon, by blocking the HR and qswitch.  That puts the etalon
normal to the beam.  Then shift 0.3mm...  and ponder the contrast in the
fringes of an analyzing etalon.  

<p>
analyzing etalon fringe contrast  co2 reflector as analyzing etalon
optical flat 1/8 inch or so thick.  Investigate things with a C315m to find
something which does the etalon trick.

<p>
coolant temp is supposed to be 20 deg C

IMAGES:20120403
<h1>20120407</h1>

<p>
The qswitch is definitely aligned...  The Maltese cross is centered on
the beam.  The resonator is more or less back in alignment as well.
The Maltese cross goes inside-out when voltage is applied, just like the
drawing in the service manual.  So /why/ isn't it q-switching?  Is the
voltage wrong?  I've tried 3k, 4k, and 5k, with no apparent difference.

<p>
The qswitch trigger timing is also just not working right.  (This turned
out to be operator error, the avalanche transistors will not avalanche 
below 4kv.)

IMAGES:20120324
IMAGES:20120327
<h1>20120408</h1>

<p>
The laser was lasing off the etalon, bypassing the qswitch, which is 
why the qswitch appears to not work.  (But I've been wrong before...)

<p>
Micrometer positions for etalon:   (normal to beam, not final pos)
top: 6.140 side: 6.305  (these values are now out of date.)

<p>
The qswitch works...  yay technology.  See qswitchcontrol_worked_20120408.hpgl
And the timing report for that shot is:

<pre>
decision at 0xc9aa  val= 0x1
min= 0xbeaa  max= 0xc249  delta= 0x39f 117 usec
lamp 0  0xc249 0xc2c2  len 15 usec
lamp 1  0x0 0x0  len 0 usec
lamp 2  0x0 0x0  len 0 usec
lamp 3  0xbeaa 0x1359  len 2756 usec
Qswitch target 0xcd49 actual 0xcd49 358 usec
</pre>

<p>
The configuration was decision 0xb00 offset 1 0x1800.  Don't remember the
voltage, but (looking at the oscilloscope plot) its too high.  Note the
triangles, one of the transistors is prematurely avalanching.  The lamda/4
voltage is 3.2kv in the configuration information for a different laser.
My qswitch driver won't work below 4kv, but some of the 2n5551 transistors
could be swapped for 2n3904s to reduce that voltage.

<p>
I don't believe that timing report though.  I rewrote the edge detection code on
the lamp inputs so it records just the first rising and first falling edge.  I
believe lamp0 saw a glitch caused by the flash lamps going off.

<p>
There are two time-bases for the qswitch.  When the trigger (from the main
CPU) arrives, the decision is scheduled and the MOSFET driver drops to 0,
so the qswitch voltage starts climbing.  It takes on the order of 200 usec to
get to Vmax.  The second time-base is the rising edge of lamp 0 (the
oscillator).  If both lamps are on and the jitter is close enough at decision
time then the qswitch will be dropped back to 0 volts at lamp 0 + offset ticks.

<p>
The pockel cell eats about 1/2 of the power output.  The etalon eats on the
order of 90% of the rest.  The osc power output is probably single digit
millijoules.  Though I have not increased the lamp voltage (from 2100V) yet.

IMAGES:20120408
<h1>20120409 </h1>

<p>
The correct analyzing etalon is 1mm long, 65 percent reflective.  Thats 
actually a more or less standard part.  Which costs $570.  

http://lightmachinery.com/catalog.html#solidetalons


IMAGES:20120409
<h1>20120410</h1>

<p>
Assembled the cases around the qswitch driver board and trigger board.  
The spurious pulses are no longer showing up in the timing report.  The cases
need a little more cutting, I forgot to leave clearance for the cover between
the 24V supply and the side of the case.  

<p>
Q-switching eats a lot of energy.  The output isn't even detectable until the
osc voltage is increased to 2300V.  I went up to 2400, and was getting on the
order of 25 mJ/pulse out of the oscillator.

IMAGES:20120410
<h1>20120414</h1>

<p>
Resoldered the D9 connector for the Accopian supply.  All the pins were cold
soldered and falling out.  I also enlarged the mounting holes for the 24V
supply and moved it away from the side of the box, so the cover will now go
on properly.

<p>
Assembled a second 200mw alignment laser ($50, from Axiz), and put it behind
the second steering mirror so it shines through the mirror and the amp.  Most
of the energy is lost trying to get through the mirror, 650nm is too close to
694nm, but its a usable amount of light for aligning down-stream optics.

<p>
I currently have the spatial filter removed.  

<p>
I then aligned the osc beam with the amp alignment beam, and then fired q-switched
though the amp.  It was more or less happy, and pretty close to aligned after
crossing the room (15 or 20 feet, to a piece of zappit paper taped to the wall.)
I tweaked the ruby beam slightly to more accurately hit the laser-diode spot.

<p>
Unfortunately its not tem00.  The spot is donut shaped, both q-switched and
free-running.  I tried moving the etalon slightly to see of that was doing it,
but nothing changed.

<p>
I wonder if its not aligned with the correct side of the HR.  I'm not sure 
how that would make a donut though.

IMAGES:20120414
<h1>20120416</h1>

<p>
Played with the spatial filter a little.  Easy to align to the alignment laser...

<p>
Started drawing an enclosure for the head.  The current plan is an aluminum frame
to hold everything, and then the sides made of oak plywood.  Its cheaper than 
aluminum and should look cooler anyway.

IMAGES:20120416
<h1>20120417</h1>

<p>
The diameter of the mode selection aperture is 0.073 inches, or a bit less than
2 mm.  According to the laser design spreadsheet thats not good enough.  And its
definitely multi-mode.  The aperture is definitely as-manufactured.  How did
it ever work?  1.3mm at the OC will work.  And if the beam is smaller, it will
actually fit through the amp...

<p>
Removing the polarizer and the pockel cell at the same time is important...  The
deviation they each add to the beam cancel out.  Adding and removing them as a
pair leaves the resonator more or less aligned.

<p>
Etalon normal to the beam:  top  6.135  side  6.315.  Side was then reduced by
0.3 mm.  Thats actually pretty close to the previous time I had it in alignment.
<p>
I seem to have fried the alignment laser which shone into the OC.  I suspect 
it reacted poorly to having the ruby fire into it...  At least it wasn't one of
the $50 lasers...
<p>
Osc only 12.7mJ, at 2300V.  After spatial filter 10 mJ.  The blob makes me think
the beam isn't /quite/ centered in the amp.


IMAGES:20120417
<h1>20120501</h1>

<p>
Spent a bunch of time building an enclosure for the head.  It has a frame made
of aluminum angle, the lid is 1/4 inch thick oak plywood.  Oak costs $30
for a 4x8 foot sheet.  A 4x8 foot sheet 1/16 inch aluminum from McMaster-Carr
is $160.  So oak it is.  I think it looks cooler than the aluminum would too.

<p>
I put a 1.3mm aperture on the axial mode selection aperture.  Its actually
52 mils in diameter, which is a little over sized but its also not right on
the OC.  The beam out of the osc looked pretty good, but after the amp
is the same slightly flattened ring as before.  Why?  Is the amp not 
sufficiently pumped?  Out of sync?


IMAGES:20120501
<h1>20120504</h1>

<p>
Charles gave me a hand getting the head into its box.  The electronics boxes
will need some brackets, and the cables will need some cable ties.  
<p>
Then we put a diverging lens into the beam after the osc, in an attempt to find
where the donuts are coming from.  Its not in the osc.  The beam looks great,
very Gaussian, straight out of the osc.  We were even bouncing the beam off 
the two steering mirrors to the amp before going to the diverging lens.  The
donuts must
be coming from the amp somehow.  Internal reflection off the interior of
the rod?  That would explain the oval-ness of the spot.  Though it sure looks
round immediately after the amp.

IMAGES:20120504
<h1>20120505</h1>
<p>
I cropped the image of the osc spot, and plotted it with gnuplot.  Which had
issues with the size of the dataset...  But the beam profile out of the osc
is extremely happy, and IMHO Gaussian.

<p>
So whats going on in the amp?
<p>
Free-running, with the new 1.3mm aperture, the osc output is 15.8mv, or
7.5 uJoules, Vosc=2300.

<p>
There is weirdness with the avalanche transistors going off immediately after
they are turned on.  I don't know where its coming from, it might be a glitch
in the analog circuitry, I have been unable to find it in the software.

<h2>Functional range of qswitch offsets:</h2>
<p>
Ideally, the qswitch would open right at the end of the lamp pulse.  So I
have all the stuff to time the flashes.  Unfortunately it doesn't work.  While
it can observe the rising edge OK, the falling edge is not accurate.
So I'll find a good delay more empirically.
<p>
First I looked at the timing with an oscilloscope and the fast photo diode.
What are the minimum and maximum delays where the laser lases.

<pre>
decision at 0xb00  offset 0 at 0xb00  

offset 
0x0b00  540 usec from the first voltage onto the qswitch   very wimpy
0x0f00  670 usec from first voltage,   less wimpy
0x1000  700 usec,   still increasing
0x1400   840 usec  pretty robust
0x1500   860 usec, very robust
0x1600   900 usec,  nothing
0x1800   960 usec,  nothing
</pre>

<p>
So its going to be from 0xc00 to 0x1600.  But the photo diode doesn't
give energy, which is what I really want.  So switch to the joule-meter...

<pre>
0x0c00 7.1 7.2
0x0d00 6.6 6.7
0x0e00 10.0 10.5
0x0f00 11.65 12.25
0x1000 8.7  9.9
0x1100 10.6 11.45
0x1200 8.8 7.9
0x1300 8.4 10.3
0x1400 7.0 5.3
0x1500  3.6 3.1
</pre>

<p>
The numbers are millivolts, divide by 2.2 to get millijoules.  I went
for 0xf00.  Though 0x1100 might make more sense.

<p>
Then I went back to playing with the amp.  After the amp, free running,
Vosc=2300 Vamp=2100  output is 410 mv or 186 mJ.  Q-switched, the output
is 330mv or 150 mJ.  So its running at about 15% of advertised output.
I haven't increased the osc or amp voltages above threshold, hopefully
that will get the rest of the power...

<p>
Screen is 120 inches from the front of the optical rail.  The piece
of tape in the middle of the frame is 1" wide.

<p>Images:  (in 2012050502)
<ul>
<li> alignment laser
<li> free-running, through the amp and lens
<li> q-switched
<li> wider shot q-switched
<li> reverse angle, q-switched
<li> side angle, q-switched    (trying to get a feel for how bright it is)
<li> spatial filter lens (but not pinhole) out of place
<li> ... closer
<li> ... closer
<li> tighter shot, q-switched 
<li> repeat of last shot
<li> black   (did not charge/fire)
</ul>

<p>
I am unconvinced that the alignment laser is centered in the amp.

IMAGES:20120505
<h1>20120506</h1>

<h2>Eye Safety:</h2>
<p>
According to a graph in the back of "Solid State Laser Engineering",
10^-7 J/cm^2 is safe at 700nm.  Actually a bit under 10^-6 is, so 10^-7 
has a safety margin.
<p>
So given a 1J laser, if the light is spread out over 10^7 cm^2 its safe.
Thats a disk with a radius of 1.78 meters.  MEH, might need a more accurate
definition of where the safe value is.  I had something more like two 1 foot
disks in mind...

<p>
OBDisclaimer: I am not a laser safety officer.  It is assumed that the reader
is competent to arrange for their own safety.

<p>
A 1 foot disk has an area of 113 in^2, or 730 cm^2.
<p>
<h2>Exposure:</h2>
PFG-01 needs 20 to 40 uJ/cm^2 pulsed and processed in SM-6...  If we have a
1' disk, 1J would get us  1.3 mJ/cm^2, so plenty
of light...  But the laser is actually doing about 150 mJ/pulse q-switched,
thats 205 uJ/cm^2.  So we'll have to be careful with the illumination, but
8x10 looks imminently doable.

IMAGES:20120506
<h1>20120602</h1>

<h2>Fun with calibration.</h2>
<p>
Ambient 77 F, coolant temp 75 F.  etalon and OC are 298 K.

<p>
VO=2300 VA=2100 SF lens installed  power out = 102mv (46mJ)
repeated the observation twice: 100mv, off-scale high 
got a charge fault, est VA=2900 power out = 425mv (193 mJ)

<p>
The amp charge circuit is acting up again.  Same symptoms as before, the
ready signal is never generated.  Kludged the software to continue.  I suspect
the board is to flexible, and popped components off.

<p>
With attenuator, VA=2900 145mv, assume output was 193mJ  divide by 0.75 for mJ

<p>
Removed SF lens, power is not significantly reduced.  So I'm putting 
it back...

<p>
With attenuator, VO=2600 VA=2900 joule meter says 330 mv, output is 440 mJ
coolant temp 70 F.

<p>
The alignment laser is pretty accurate, but with the diverging lens installed,
the reference beam is too dim to see projected.  The ref beam is also way off
center, and the over head mirrors are not adjustable enough to get it back
in line.  

<p>
Attempted to make the first hologram (number 96.1).  It went black
in the developer (SM-6) but there was no diffraction.

IMAGES:20120602
<h1>20120603</h1>

<h2>Fun with debugging...</h2>

<p>
Kludged an etalon into the optics, in search of interference.  It was
way off center, so the spatial frequency was high, but there was definitely
an interference pattern.

<p>
The qswitch is also verified to be single pulse.

<p>
And then the ready indication on the amp quit working...  output was
430 mv (195 mJ) at Vamp=2300 free-running.  It can still report the
voltage, so
the problem is in the voltage comparator again.  Its like there must be a
constant number of things which aren't working, and I got the count too
low.  :-P  I have kludged the firmware to continue working on optical issues.

<p>
Rearranged the optics to get the big overhead reference beam mirrors square.
Beam splitter is now a horizontal prism.

IMAGES:20120603
<h1>20120612</h1>

<h2>First Success</h2>
<p>
I have finally gotten a viable hologram, number 99.1, the fifth attempt
with this apparatus.

<p>
The problem is that PFG-01 sensitivity rolls off at 680nm, and we're at
694nm.  The datasheet specificly says not for use with ruby. (I should have
read more carefully... MEH)  So
I tried some of an ancient roll of 10E75 holotest film.  According
to the datasheet, its looking for on the order of 2 uJ/cm^2.  

<p>
The hologram went black nearly instantly, and had contrast to an unexposed
corner.  I pulled it out of the developer at 45 seconds (as opposed to the
specified 2 minutes).  It bleached in 4 minutes, but had lots of fog.  The
fog is not present on the unexposed corner, so its not from the age of the
film.  

<p>
There is a pattern of lines over everything.  My first thought is that the
etalon in the osc is not aligned and its multi-mode.  But the last bounce
mirror for illumination is second-surface, I bet its coming from there.

IMAGES:20120612
IMAGES:20120616

<h1>20120622</h1>

<h2>Revisiting Eye Safety...</h2>
<p>
Chapter 23 of the "Electro-Optics Handbook (2nd Edition)" "Laser Safety in
the Research and Development
Environment" states that the intrabeam laser ocular exposure limit at
700nm 1ns to 18us is 0.5 uJ/cm^2.
<p>
http://www.magergy.com/documents/Ebooks/Electro-Optics Handbook (2nd Edition)/87161_23.pdf
<p>
To get 1J (rated output, not observed) to 0.5uJ/cm^2 it would have to be
spread over 2 million cm^2, or a disk 900 cm in diameter (35 inches). 
Not entirely possible for my configuration.  
<p>
But, for extended source ocular exposure (IE: diffuse reflection) there
is a correction factor, provided that the reflection covers large enough
of the viewer's field of view (a).  amin must be larger than 1.5 (0.08 degrees)
mrad  viewing angle.  Greater than 100 mrad  (5.7 degrees)
is no longer considered beneficial (amax).

<pre>
CE = a/amin for amin < a < 100 mrad.
CE = a2/(amin * amax) for a > 100 mrad
</pre>
<p>
Assuming its 100mrad (my configuration should be larger...) the correction
factor is 8.5*10^3.  That number is from the book, and I'm not sure how
they are getting it given the equation for CE above.  I keep getting 1333.
<p>
But, given the correction of 8.5*10^3, now we get 4.2 mJ/cm^2, which will
have an area of 238 cm^2, or an disk 10cm in diameter (about 4 inches).
<p>
Given the correction of 1333, the illumination can be 666 uJ/cm^2.  So 1J
would be 1501 cm^2, or a disk 24.6 cm in diameter (9.7 inches).
<p>
Or, with a correction of 8500, its 4250 uJ/cm^2, or a disk 7 cm in diameter
(3.8 inches).  The number cited in Practical holography is a disk 6 inches 
in diameter.  

<p>
OBDisclaimer: I am not a laser safety officer.  It is assumed that the reader
is competent to arrange for their own safety.

<h1>20120624</h1>

Pricing of some optics...
<pre>
wave plate   1" diameter 10J/cm^2  670nm  $304
polarizing beam splitter 1" 2J/cm^2 620-1000nm  $203
polarizing beam splitter 1" 10J/cm^2 532nm  $500
analyzing etalon  $570
</pre>

I would also like a pony.

<h1>20120715</h1>

<pre>
ref beam length 129 inches.     4+38+58+29

obj beam length 
	3+14 to get off optics board     1/2" diameter   (approx)
	23 bounce to bounce		3.375" diameter
	23 bounce to bounce		6.25" diameter
	30 bounce to diffuser		10" diameter
	21 diffuser to subject
	12 subject to film
</pre>

<h1>20120818</h1>

<p>
Found the popping sound.  The illumination beam expanding lens was in
backwards, and the reflection focused to a point, ionizing the air.
(see images)

IMAGES:20120818

<h1>20121030</h1>
<p>
Started working on V2 of the main control board.  The board is too
thin, and keeps flexing and popping components off, I don't feel
like trying to fix it any more.  
<p>
I also want to replace all the random connections to the board with 
an edge connector.  I underestimated how annoying it would be to
work on the board, or how often I'd end up doing so...  :-P
<p>
So, given a 44 pin edge connector (used on other projects...) its
amazing how quickly they went.  I didn't realize there were that many
lines.  

<h1>20121104</h1>
<p>
More or less finished the board layout, though the majority is unchanged.
I bailed on having separate
GNDs for every signal to the osc and amp power supplies, and that
saved enough pins to get everything through a 44 pin edge connector.
<p>
The panel is now a 2x6 matrix, one column is the mode switch, and the
other has charge, fire, and dump.  The dump switch has multiple contacts,
so it will break the interlock in hardware as well as inform the msp430.
<p>
The msp430 now has a pair of relay drivers, one so software can break
the interlock, and possibly the other so software can turn on the main
power as well.
<p>
The interlock observation is now fully implemented, as opposed to having
an extra resistor tacked to some wires.  It indicates open when actually
closed, but there is now a separate line to observe that the +12V rail is
powered.  The 12V rail is also now connected to an analog input via a voltage
divider.  It would be nice to observe the -12V rail too, but I don't feel
like messing with yet another opamp, and it would have to be powered by the
rails its supposed to be observing.
<p>
I have reduced the I2C pullup resistors to 4.7K.
<p>
Given that a laser is required to have a key switch for the main power...
Is a password controlled software implementation acceptable?  (The FDA says it is.)


<h1>20121122</h1>

<p>
So we got the CNC mill running, which means:
Fun with the heat exchanger...
<p>
Body is plexiglass, and about 6 hours on a CNC mill.  Sides are
47 mil thick 304 stainless steel, gasket is locktite 587.  Barb 
fittings are nylon 1/4 NPT to 1/2" ID tubing, sealed with teflon
tape.
<p>
The max temp a TEC can survive is 80 degrees C, or 176 degrees F.  
<p>
The TECs I have are weird ones off ebay.  They are approximately a
Nord TM-127-1.4-8.5.  Imax is 8.5A, Vmax is 14.6V, delta Tmax is 71 (C),
and will move up to 74W.  
<p>
I have no idea what the cooling capacity of my heat sinks are.  They
are generic extruded aluminum with a fan, surplus CPU heat sink assemblies.
<p>
The power supply I have is 300W at 12V, or about 24A.  At 6A (2 ohm
current limiting resistor) we will be dumping 72W into the TEC, and
with 0 degree delta can move 74W of heat.  We won't be at a 0 degree
delta...  at a 30 degree C delta we can move 45W (there is a graph 
on the datasheet).
<p>
So the heat sink needs to move 72+45W=117W.  Which is extremely
optimistic.
<p>
At 12V, no current limiting resistor (it would have to be rated for
70W, that is not the right answer) the heat sink hits 150F.  That is
not sustainable.  So, put two TECs in series.  At 6V, the heat sink
stabilizes at around 100F.  Which is sustainable.  So temp delta of
40F, (22C) which is well within range.  Current into the switching
supply is 0.7A at 120VAC, 84W.
<p>
With 2 strings of two TECs, current into the supply is 1.25A, or 150W.
<p>
With 3 strings of two TECs, current into the supply is 1.78A, or 213W.

<h1>20121123</h1>

How much energy can the heat exchanger move?

4000ml of water in the system.  Ambient temp is 70F.  Temp was recorded at
1 minute intervals using a alcohol thermometer (first column in C) and an
IR thermometer (second column in F).

<pre>
19.0	66.5
18.9	66.5
18.5	66.0
18.5	66.0
18.1	65.6
18.0	65.0
18.0	64.5
17.9	64.5
17.6	64.0
17.5	64.0
17.4	64.0
17.1	63.5
17.0	63.5
17.0	63.0
16.9	62.5
</pre>

Heatsink was 100F, current was 1.52A at 120Vac (observed at the end)
<p>
Drop of 2.1 degrees C in 15 minutes, which is 35169.12000J in 15 minutes.
Or 2344J per minute, or 39 watts.  For which we used 182W.  I'm uncertain
that is sufficient.

<p>
Or 2344J per minute, or 39 watts.  For which we used 182W.  I'm uncertain
that is sufficient.

IMAGES:20121120
IMAGES:20121121
IMAGES:20121122


<h1>20121201</h1>

<p>
Lots and lots of assembly.  The V2 board is completely populated.

<ul>
<li>The DACs are happy, as far as I2C goes.
<li>LED drivers are happy.
<li>The new matrix panel layout is happy.
<li>RS-232 is happy, both to the host and the qswitch controller.
<li>The new relay drivers are happy, with no current limiting.  They are
running off the unregulated unswitched supply, which is about 7V, and
the relays are rated for 9V, so it probably makes sense.
<li>The interlock is reading backwards or something...  
<li>OSC voltage reads constantly high.  
<li>Nothing will charge right now, I suspect the 555 is not running.  Or 
perhaps the level shifters are unhappy.
</ul>

IMAGES:20121208

<h1>20121223</h1>

<p>
I put some heat sink grease on the cold side of the TEC modules, and
increased the voltage of the power supply to about 13.5 volts.  Any higher
and the power supply got weird.  During alignment tests, the coolant did
not get above 68 F.  Ambient is approx 69 F.
<p>
More fun with geometry, rearranging so we can do a transmission diffuser
instead of a reflection.

<pre>
ref beam length 129 inches.     4+38+58+29

obj beam length 
	3+14 to get off optics board     1/2" diameter   (approx)
	39 bounce to bounce		
	29 bounce to bounce		
	27 bounce to subject
	12 subject to film
</pre>

<p>
The max osc voltage is 2500V (assuming current calibration).  Its actually
a tad higher, but the OV card trips at 2600 just after the ready indication.

<p>
The max amp voltage is more than 2900.  I didn't go above 2900 due to the
ominous crackling that tends to happen at that voltage.

<p>
The qswitch may or may not be very well timed, due to the falling edge bug.
However it put a very firm hole in the zappit paper compared to free-running.

IMAGES:20121223

<h1>20121224</h1>

After pondering the holograms, I lengthened the illumination beam about 12 inches.

<pre>

ref beam length 129 inches.     4+38+58+29

obj beam length 
	3+14 to get off optics board     1/2" diameter   (approx)
	42 bounce to bounce		
	33 bounce to bounce		
	18+13 bounce to subject
	12 subject to film

total 135
</pre>

<p>
I suspect I'm actually wrong, and mistook where the spot from the diffuser
is shining for beam length problems.

<p>

After much debugging, It is finally time to shoot a hologram on some fresh film.
<p>
Hologram number 104.2 on a harman holo fx plate in SM6 developer for 2 minutes
and Ferric EDTA bleach for 2 minutes was extremely successful and I'm calling 
the project a complete Success.

IMAGES:20121225

<h1>20130119</h1>

<p>
Poking at the peltier cooler a bit, with gruntier heatsinks.

<p>
The datasheet describes the TEC's performance with a hot side temp of 50 degrees
C, or about 123 degrees F.

<p>
I got a pair of copper heatsinks, to see if they work any better than the 
aluminum ones.  With the copper heatsink, the hot side seems to be about
108 degrees F. 

<p>
The aluminum heatsink hit 122 deg F, and 5.5K on a thermistor (which is
allegedly 105 F).  It had not quite stabilized when I pulled the power.

<h1>20130126</h1>

<p>
ref beam length 129 inches.     4+38+58+29

<p>
obj beam length 
<ul>
<li>	3+14 to get off optics board     1/2" diameter   (approx)
<li>	42 bounce to bounce		
<li>	24 bounce to bounce		
<li>	23+13 bounce to subject
<li>	12 subject to film
</ul>
<p>
total 131
<p>
The lens expanding the green laser is a -8mm lens.

<h1>20151231</h1>
<p>
Saving some old notes from paper:

<pre>
The pin out of the etalon heater assembly:
DIN connector, not the "correct" pin out
looking into male
    3
 2    4
1      5

1	green	temp sensor
2	black	frame GND
3	red	heater
4	yellow temp sensor GND
5	blue	heater GND
heater is 18 ohms total, and consists of 6 resistors

</pre>

<h1>Big Pause Here</h1>

<p>
So, I successfully used the laser and my pulsed apparatus for several years here.  Unfortunately, Ilford
then decided to discontinue the holographic plates I was using (again).  This is why people like second
sources.  There is some interesting
history there though.  The Illford "holoeffect" plates were really Agfa's Holotest film from the 90's, the
companies in question bought each other a couple of times.  

<p>
So now the only available deep red (694 nm)
sensitive plates are made by Yeves Genet at Ultimate Holography.  Unfortunately, my laser is not bright
enough to expose them.  The obvious solution is...  a bigger laser.

<h1>20171021</h1>
<p>
<h2>Investigations into getting MOAR POWER...</h2>
<p>
The beam diameter straight out of the osc is 0.052 inches, which matches the
axial mode aperture.  Looking at it just before the spatial filter, it is 
not measurably (with calipers) diverged.
<p>
At the entrance to the amp (flat against the outside of the HV enclosure)
the beam is also 0.052 inches.  
<p>
At the exit of the amp, zappit paper is ineffective...  absorbed by the amp,
or too bright and get the entire 3/8 inch disk of the amp.
<p>
The model, assuming a 150mm focal length lens  (found that number in the
manual somewhere) says that the beam enters the amp with a diameter of 0.103 inches
and exits with a diameter of 0.228 inches.
<p>
frame 15, the 3/8 circle is 150x145 pixels, the beam is 99x98 pixels, making
the beam 0.244 inches in diameter.  
<p>
frame 18 3/8 circle is 1464 pixels tall, beam is 887x1002 (which is odd).
Using only the height numbers because the 3/8 circle width was cropped by a
shadow.  Beam diameter is 0.257 inches.  
<p>
So why the approx 0.03 inch difference?  
<p>
And is moving the spatial filter worth the effort?   
<p>
Model, before:  entrance 0.103  exit 0.228 length 8 inches  11.75 from pinhole
	0.2687852392 - .0326347978  v= 0.2361504414   (of 0.88357)
<p>
Model, after:  entrance 0.130 exit 0.255  length 8 inches  14.75 from pinhole
	0.3872847387 - 0.0652600416 v= .3220246971  
<p>
So model says about 1.36 times the energy.  increasing from 27 percent of the amp
volume to 36 percent of the amp volume
<p>
real numbers:
Before:   0.052 to 0.244  in 8 inches    (we'll be optimists)  11.75 from pinhole
	0.3415088551 - 0.0083178896  v= .3331909655   (38 percent of amp volume)

<p>
Removed the pinhole, unqswitched output is 0.980V or 0.445J.  (maybe)
<p>
Removed the spatial filter lens too, unqswitched output is 0.548V or 0.249J.  

<p>
So 56 percent of the power.  
volume without spatial filter is 0.170 inches^3   volume ratio is 0.056
So we're off by an order of magnitude.
what is r=0.142 inches?  (as measured with zappit paper and calipers)
v= .1266941472 ratio is 38 percent.  

<p>
So pure volumetric model is poor.  

<pre>
frame 41 is amp and lens without pinhole.  Is it bigger?  Comparing to frame 36,
I'm going to say Yes.
frame 41   3/8's is 1339x1306  beam is (approx)  1068x1117   (0.299 x 0.321)
frame 36   3/8's is 1163x1179  beam is (approx)   682x706    (0.220 x 0.224)
</pre>

<p>
I am uncertain about the measurement.  The camera didn't move, so the 3/8's circle
should not have changed.  But its bigger in pixels too.  I bet the camera refocused,
and the lens breathed (size of the image varies with the focus, a very common problem.).

<p>
Removed the pinhole, alignment failed...  unqswitched output is 0.992V or 0.451J  Whee.

<p>
Got the pinhole back into the system...  used the resonator laser to get the
pinhole close enough to find it.  Then got the other laser back into alignment.

<p>
Pondering frame 61.  3/8 circle is 1482 pixels high, beam is 1076 x 1107  
So beam is about 0.272 by 0.280.  We have acquired a about 0.036 inches of diameter.

<p>
Increasing the amp voltage to 3300 was more productive, about 25 percent more light.
See table in paper notebook.

<p>
Frame 62, the alignment laser's disk is 1479 x 1762   (not round because camera is
off-axis)

<p>
subtracting frames 61 and 62...  calling the alignment laser's disk the 3/8 circle,
the beam is 1032 x 1092  pixels, or 0.262 x 0.232 inches (average is 0.247).  The
[incorrect] model predicts an output size of 0.255 inches.  

<p>
The model has the wrong focal length for the lens...  its -180mm not -150mm.

<p>
The alignment laser disk is 3/8 of an inch in diameter.  As measured without the
lens.  So there is the real dimension.  The beam really is  0.262 x 0.232 inches
as observed in frames 61 and 62.  So we can make it larger, assuming that a larger
volume will increase our gain.

<pre>
Correcting the model for 180mm lens.
Before	entrance 0.078  exit  0.181   length 8 inches  11.75 from the pin hole
	v= 0.1506767396022389
After   entrance 0.100  exit  0.203   length 8 inches  14.75 from the pin hole
	v= 0.20682275990842008
Without the lens, diameter= 0.052 length of 8 inches  v=  0.0169897330706136 

import math
rin=0.078/2.0
rout=0.181/2.0
l=8.0
p=11.75
(1/3.0*math.pi*math.pow(rout,2.0)*(p+l)) - (1/3.0*math.pi*math.pow(rin,2.0)*p)

volume of a cone is 1/3*pi*r^2*h

</pre>

<h1>20171022</h1>

<p>
The distance between the spatial filter lens and pinhole on Ed's laser is 156 mm.
Which matches the 150mm focal length documented elsewhere.  

<p>
The resonator is 23 inches long, with a 4 inch long rod.  Two 4 inch lamps in series
2500V in a 250uf cap.

<h1>20171024</h1>

<pre>
Oscillator volume as a function of aperture  (approx)
mm	inches		inches^3
1.3	0.052		0.00849		<---- current config    (best, according to spreadsheet)
1.6	0.062		0.01208					(OK, according to spreadsheet)
1.8	0.070		0.01539		<---- stock		(stock)


transverse mode loss:
aperture mm	inch	tem00	tem01		osc volume
1.3		0.052	14.1%	41.8%		0.00849
1.6		0.063	5.12%	26.7%		0.01208	(1.4x)
1.67		0.066	3.92%	23.73%		0.01369 (1.61x)
1.8		0.070	1.3%	14.5%		0.01539	(1.8x)

</pre>
<p>
The minimum loss for tem01 for usable single-mode is 25%, 35% is better.

<h1>20171028</h1>

<p>
osc only output Frame 12  joulemeter reports 26.6mV 12 mJ.  (wheeeee) aperture is 0.052 inches.

<p>
0.066 inches diameter frame 13, 14  joulemeter reports  62mV 28.18 mJ  aperture is 0.066 inches (stock, measured with calipers)

<p>
So that is 2.3 times as much energy.  volumetric model predicted 1.61 times.
 While thats better, I'd prefer an accurate model.

<p>
Ron Michael's spreadsheet says 25% or better...  we're getting 24%, and lots
of energy.  That the stock part landed so close to Ron Michael's spec is 
encouraging.  Its worth continuing with that configuration, and seeing what it
does to coherence length.  (We were better than 6 feet with the 0.052 
inch aperture, as observed with holograms.)

<p>
frame 15 is the osc and amp not qswitched.   (mode D)
frame 16 is the alignment laser through the amp.

<p>
3/8 disk is 1799 x 2080, beam is 1324 x 1531 so beam is 0.276 x 0.276 inches.

<p>
So we have increased the osc volume, increased the amp volume, increased the amp voltage.


<p>
34.? (15.4 mJ)  free running qswitched: 17.65 17.9 (8.0mJ)   joulemeter in the
illumination beam right behind the diffuser.  

<p>
Moving joulemeter to ref beam, to match older observations...  4.51 mV or 2 mJ per 20.25 cm^2
so ref beam is 98 uJ/cm^2.  That is up from 1.714 mV (38uJ/cm^2) on 20170909.  so maybe
2.6 times brighter.

<p>
Reobserving just the ref beam (blocking obj beam) got 2.36mV or 1.07mJ or 53 uJ per cm^2.
More like 39 percent brighter.  I don't remember if I properly blocked the obj beam
for the observation on 20170909.

<p>
Moved the sensor to be exactly where the middle of the plate goes.  The power was too
low to reliably measure.  Both with and without an object.  Not a good sign...

<h1>20171110</h1>

<p>
The beam height is 90mm, according to a drawing in the manual.  I do not believe
that number.  Measuring the actual laser, the beam height is 60mm.  This may be another
difference between a system 2000 laser and the later ones.

<pre>
the PFN inductor on the oscillator is 127 uH.
	the wire is about 0.185 x 0.080 inches (rectangular)
	the coil is 3.25 inches in diameter (OD) and 2 inches long.
the series trigger transformer is 12.633 mH.
the isolation inductor on the amp is 4.77 mH.  
</pre>

<p>
The pfn program is extremely wrong...

<p>
More fun with the key switch...  I want a JD7510A  mouser has a LK5ANB126N3
A "one position" key switch has 2 positions...  

<pre>
6.5 inches from the end of the amp to the end of the rail.
9.5 inches from the end of the amp to the inside of the lid.  The lamps are 11.5
inches long.
</pre>

<p>
People on ebay sell high power crossover inductors, 12mH is not even a large
value...  So acquire one, and add a primary for the series trigger transformer?

<h1>20171230</h1>

<h2>Various screwups on the new controller board:</h2>
<ul>
<li>
I rotated the pins of the 337 negative voltage regulator.  But at least it
really is -15V.  

<li>
The 12V rail really needs to be 15V.  Correct 2940 regulators have been ordered.

<li>
All the diode footprints are wrong.  And backwards.

<li>
The DAC footprint is wrong, way too big.  The component is not available in the
correct package.  Excessive soldering kludges have been implemented.

<li>
Need current limiting resistors on the optocoupler inputs.  (put them on the BNC connectors)

<li>
protective diodes on relay drivers.   (put them on the relay bodies)
</ul>

<p>
<h2>Fun with voltage dividers and stuff</h2>

<p>
So the PD2000 observes the capacitor voltage, it is 20M and 33K, so it has a ratio
of .00164728198472520341 which puts 3000V at about 5V.  Which is a pretty convenient
value for 5V DACs and stuff.  (Except that mine is 2.5V.)

<p>
The msp430's DAC is 0 to 2.5V.  So set the gain of the inverting opamp (since the
main cap is actually negative polarity) to about -1/2, so that 3000V is full scale?

<p>
Except that right now the amplifier voltage is set to 3300 volts.  I don't entirely
trust that number, need to re-observe with more trustworthy instrumentation.

<h1>20171231</h1>

<p>
Re-measured the amplifier voltage of the current JK laser circuitry.
The meter reported 2905 volts, the controller reported 3583.  The set point was
3300.  So everyone is wrong.  I bet the OV card is set to 3000V.

<p>
The ADC pegs at 5.98V, which would be 3630 V, which is over our max voltage for the
original JK circuitry.  I haven't actually determined the operating voltage of the
additional amp yet.

<h1>20180101</h1>

<pre>
LED part numbers for the control panel.  
red TLHR5401
yellow TLHY5401
green TLHG5401
</pre>

<h1>20180106</h1>

<p>
Dinking with the over-voltage card.  I failed to re-re-re-re-flood the ground plane,
so Vcc is shorted to GND.  yay technology.

<p>
The PD2000 for the OV card is 20M into a 1M resistor, so its ratio is 0.0476190476.
But the input resistors on the OV card are in parallel with the 1M resistor on the 
PD2000.  Which will get things down to the OV card's adjustment range.

<p>
We want the set point, 4000V to be 6V.  Which is a ratio of 0.0015.  If the bottom
resistor is 30K, that will work.

<p>
The variable resistor on the OV card has a range from 5 to 6.5 volts.  Lets get the
voltage to 6V.  

<p>
pin 2 is system GND.  pin 1 goes negative, and will trip the card at about 3.7V, with
r1=10K and r2=not installed.

<h1>20180107</h1>

<h2>Fun with assembling the trigger board:</h2>

<p>
I permuted the pins of both SCRs.  There is also an error where D7 should not be
connected to D8.  The voltage from the 6.8V zener is fine...  but the 600V is more
like 440V.  I had figured at the time that it was caused by the capacitor not being
connected, and the lumpy DC confusing my meter.

<p>
There is much unhappiness with overheating diodes.  D11 overheats when there is no
output connected (but D11 should not be seeing any current, C4 should block
the DC). D9 overheats when there is.  I'm not sure why either of them are
conducting at all.  Its like the rectifiers aren't.

<p>
The inductance of the primary of the trigger transformer isn't -32 uH.  MEH.  

<p>
The secondary has 23x20 or 460 turns.  We need about 20KV to trigger the lamp, the
input is 600V we need about 33x, so the primary would be 14 turns.  Which is surprisingly
few.  Perhaps too few.  :-P


<h1>20180114</h1>

<p>
The pump chamber seems to be coming out.  The clamps for the rod need to be a little
larger.  (drawings adjusted)  The base plate for the pump chamber is annoyingly large,
it might fit in my mill, by the skin of its teeth.

<p>
Then there is the trigger board...  The problem is that the little SCR /isn't/ an SCR,
its a programmable unijunction transistor.  It has 4 layers like an SCR, but the gate is
the other inner layer.  So the symbol was not a conveniently drawn SCR.  So it was
incorrectly on, and the big SCR was conducting, which pissed off everything.

<p>
The part is still available, but should probably be re-engineered at some point.


<h1>20180211</h1>

<p>
Finished all the wiring.  Need to get another roll of bigish stranded hookup wire.
Reversed hot1 and hot2 on amp0, but that was the only error on the 240V stuff.

<h2>Initial shakedown:</h2>

<ul>
<li>Dangling 240V line, which didn't actually hit anything.  
<li>The supply LED works
<li>The interlock LED does not, maybe
<li>The ready LEDs might work
<li>the power LED works

<li>remote fire works
<li>The mode knob works for 2-5, but not 0 or 1

<li>All the panel buttons work, but there is some weirdness when the mode knob is turned,
it seems to press the charge button.

<li>The Qswitch serial lines are correct.
<li>There is some baud-barf when ? is pressed.
<li>The Power switch turns everything on, but it does not stay on.
	Dump relay driver failure
<li>Its does not turn on at all when the interlock is open.   (Expected)
</ul>


<h1>20180212</h1>

<p>
The panel button and mode switch issues were caused by poor soldering of the
pull-down resistors (couple of opens, and position 0 was shorted to GND)
and polling the bits too quickly after asserting one of the column pins. 
The 10K pull-down didn't discharge the line fast enough.  So I added a delay.  

<p>
It still turns on but immediately turns off, and the interlock optocoupler is
returning GOOD when it should be BAD.


<h1>20180418</h1>

<p>
The trigger transformer primary is 15 feet of purple wire, and has 14 turns.

<h1>20180518</h1>

<h2>Ideas for tomorrow:</h2>

<li> Remove the aperture, and optimize the HR, as per section 4.4 of the manual.
Reduce voltage and repeat, for more precision.
<li>
Attempt to find alignment marks on polarizer, to make sure its square with
everything else.  The pockel cell has alignment marks, and is aligned to
them.

<li> Make sure the qswitch is qswitching by observing waveform with DET10.

<li> Put blocking card back in, and make sure we're resonating between the OC and HR, not off the etalon.

</ul>

Tuned the etalon by resonating off it (card between etalon and pockel cell).
How can we be sure we didn't resonate on the windows?  There was that little
spiral pattern of reflections as we got close to perpendicular to the alignment
laser.
How to tune etalon?  

<p>
The procedures in the manual tend to set the OC, and then only move the HR.
The OC is definitely flat, its a resonant optic on my laser.  Since a
flat to flat resonator is a pain in the neck to align, the HR is most likely
curved, with a long focal length, like 3 feet.

<h1>20180519</h1>

<p>
I removed the aperture and drilled out its hole a little, because I am 
concerned about reflections off the edge of the rather ragged hole
screwing things up.  The original measured diameter was 0.065 inches.
I drilled it out to 0.073.  I then drilled a 0.063 inch hole in a piece
of brass shim stock, and epoxied that to the aperture.  So the final
diameter is 0.063, and has nice square edges.

<p>
I then spent a whole lot of quality time with the HR, finding the brightest
spot, and then reducing the lamp voltage and doing it again.  

<p>
I then replaced the aperture, and did the same operation.

<p>
I then put in the analyzing etalon, and dinked with many things.  
One significant observation is that if the osc lamp voltage exceeds 2400V,
the ring contrast drops.  This is my current favorite explanation for 
the contouring in the holograms made with Rain.  

<h1>20180609</h1>
<p>
I finally managed to measure the flash lamp pulse length.  I did it with
the big divide by 100 probe, and then a divide by 10 probe.  The capacitor
is taking on the order of 4 milliseconds to discharge.  The pulse can not
be seen by the DET10A and the qswitch controller because it slope is too
flat.

<p>
The problem is that the trigger transformer is 12 mH air core.  The JK
trigger transformer has an iron core, it saturates when the pulse
goes off and that reduces the induction.  But mine are air core and
do not saturate, so the induction stays high and the PFN is very very
slow.

<h1>20180615</h1>

<p>
New inductor...  Got dropped during shipping...  Its coil is 15 x 20 turns,
so 300 total.  To get 20Kv from 650V we need 30x, so 10 turns of primary.
The question is if it will saturate "correctly".

<p>
The original is 460 turns...  so not many fewer...  I have a bad feeling.

<h1>20180616</h1>

<p>
7 turns on the new inductor doesn't work.  Nor does about 14, but it
was not well wound.  
Should be 10, for a ratio of 30, so 650 * 30 = 19500
14 turns also doesn't work.

<h1>20180623</h1>

<p>
New inductor...  2.5 mH  13 x 17 turns so 221 turns.  so 7 turns of primary.

<p>
I thought I had ordered an iron-core inductor.  But I got two air-cores.

<p>
Tends to work once or twice, and then quit working.  

<pre>
12-14 turns on a 460 turn secondary  (23 x 20)    38.333 to 32.857 times
7 turns on a 221 turn secondary      31.5 times   
6 turns on a 221 turn secondary      36.8 times

12-14 turns on 221 turn secondary  18.4 to 15.7 times    11960 to 10205 volts 
</pre>

<p>
The 460 turn one is reliable...  but the 221 turn one generally sucks.  One
time it worked, and got a fall-time of 3 milliseconds.  Which is 1/3 to 1/2 of
the required speed.  The same voltage would be 6 or 7 turns of primary on the 221
turn secondary. but that also sucks.

<pre>
primary of 13 turn on  460 turn secondary is 26 uH

primary of 13 turn on  221 turn secondary is 23 uH

doesn't work with 1 cap
reversed polarity, still sucks

primary of 5 turn on 221 turn secondary is 4.7 uH

There were a couple of large arcs somewhere in the charging supply.

Works fine with the 14 to 460 inductor, except for the uselessly slow part.

</pre>

<h1>20180624</h1>

<p>
I bypassed the 132uH inductor on the trigger card, which sped up the edge
of the 650V pulse, and now the 5 turn to 221 turn trigger transformer
is reliably firing the lamp.  The pulse is now about 2.5 milliseconds long,
still too slow though possibly usable.  It is visible to the DET10 and
sometimes visible to the qswitch controller.  It is extremely delayed
compared to the other lamps though.  Is that a polarity issue?

<p>
The discharge time through the 12mH trigger transformer is about 5.4 milliseconds
perhaps a bit shorter, I'm interpolating off a screen shot.  
The 2.5 mH got it down to 2.5 msec.  
So I'm thinking 0.5 to 1 mH?  

<p>
The 285 uH inductor with 2 turn primary didn't work.  Not surprising.

<h1>20180703</h1>

<h2>New inductors... </h2>

<pre>
iron core 2.5mH about 148 turns   primary 3    49x    32064V
air core 0.8 mH about 128 turns   primary 3    42x    27300V
air core 1.0 mH about 162 turns   primary 4    40x    26000V
air core 2.5 mH about 221 turns   primary 4.5  49.1x  31850V   2.5 milliseconds

The lamp is probably more like a max trigger of 16kv, all those ratios are too big

iron core 2.5mH about 148 turns   primary 6    24.6x    16032V
air core 0.8 mH about 128 turns   primary 5    25.6x    16640V
air core 1.0 mH about 162 turns   primary 6    27.0x    17550V
air core 2.5 mH about 221 turns   primary 8    27.6x    17956V

Trying air core 0.8mH  5 turn primary:

It only triggers maybe 60% of the time.  
DET10a says flash length is 1.55 msec, qswitch reports 657 usec.

rise time 380 usec

firecomplete
decision at 0x6d13  val= 0x8780
min= 0x6345  max= 0x6391  delta= 0x4c 9 usec
lamp 0  0x6213 0x0  len 5140 usec
lamp 1  0x6391 0x7cec  len 825 usec
lamp 2  0x6345 0x8624  len 1135 usec
lamp 3  0x6ca8 0x84b9  len 783 usec
lamp 4  0x0 0x0  len 0 usec
Qswitch target 0x7391 actual 0x7391 569 usec

</pre>

<p>
Not especially reliable triggering.  maybe 50%

<p>
The sound is a much sharper pop than with 2.5 mH.
The qswitch controller is getting pretty much every pulse, with the
optical fiber wedged between the lamp clamp and the rod clamp.
I think that pretty much proves the pulse slope theory.

<h1>20180704</h1>

<p>
I put a 5 turn primary on the iron core 2.5 mH, and it failed
to trigger.  Not especially surprising.

<p>
So I removed a turn from the 0.8 mH air core trigger, so 4 turn primary.  
That then triggered three of three times.

<p>
With a total inductance of 0.9 mH and a pulse length of 1.5
milliseconds, I think its a little long but viable.  

<pre>
12mH  + 0.1mH   5.4 msec
2.5mh + 0.1mH   2.5 msec
0.8   + 0.1mH   1.5 msec
</pre>

<h1>20180715</h1>

<p>
So I fried something...  The trigger board SCR, the PUT (which drives the SCR) the transistor
which drives the transmission line to the PUT, and just because I was there, the inverter
transistor for the driver transistor since its a PNP.  

<h2>Replace all the things...</h2>

<p>
I then finally managed to see what happens when you don't bother with a 100uH inductor in
series with a 800 uH inductor.  It was slightly shorter, maybe 1.54 milliseconds instead of
1.55 milliseconds.  Within spec, and fitting the big 100uH inductor on the board was being
annoying.  When it doubt cut it out.

<p>
I then fabricated another trigger transformer (IE: wrapped a primary around a 0.8 mH inductor)
and assembled all the stuff for the second flash lamp.  The two trigger transformers are in
parallel, from previous experiments series did not work.

<p>
I then tried the second flash lamp alone.  It worked the first time...  (suspicious...)

<p>
I then connected the 12mH inductor between the two caps as an isolating inductor, and tried
firing both flash lamps at once.  The waveform looked pretty much the same.  The qswitch
controller said it was 1248 microseconds long, which was slightly longer than the 1145 or so
that the single lamp would do.  

<p>
I unfortunately have no good way to determine that both lamps are firing.  Though if one did
it would discharge its own cap and then the other cap through the 12mH inductor which should
be a significantly longer pulse.  

<p>
I could put them on separate diodes from the charger, such that they can not both discharge
through a single lamp.  However which cap should be monitored for the voltage?  Up-stream
from the diodes?  How asymmetric could they be?

<h1>20180728</h1>

<p>
More enlightenment...  the second amp is extremely late, 7 milliseconds late.  So the
qswitch controller clock wrapped, and indicated it was in sync when it extremely was
not.  I have added some more code to the qswitch controller so it has a 32 bit clock,
so the error is more easily observed.

<p>
So, why is it 7 ms late?  And thats about the period of the 16 bit clock.  Looking
at the trigger pulse vs the flash lamp output, it seems to be triggering on the falling
edge of the trigger pulse.  Why?

<p>
The exact behavior of the flash lamp controller is that it does the rising edge when
specified, leaving the output high, and then lets the clock loop on the last one
(AMP2), then sets all the outputs low.  So the trigger pulses are all about 7ms long.
The reason for that behavior is that in previous efforts, with shorter trigger pulses,
the trigger boards would not reliably trigger.  

<p>
So the first theory is that its triggering on the falling edge, but that may also be
a coincidence and the flash lamp just takes that long to trigger.  And that delay 
is from the extremely large PFN inductance of the trigger injection transformer (800 uH).

<p>
So I shortened the trigger pulse in software.  Amp1 is definitely triggering on the
falling edge of the pulse.  No idea why...   So I reset all the delays so it gets fired
first and the osc and amp0 get fired later.  So the timing is closeish...  And I think its
actually amplifying.  I haven't determined how much of an improvement it is.  The timing is
definitely poor though.

<p>
Amp1 does seem to work.  Except when the timing glitches.  The problem is that its gain
is less than its loss.  Straight out of amp0, the joulemeter reports 306mV attenuated,
and with amp1 in place it does about 96 mV.

<p>
And the trigger board fried itself again.  But the PUT and line driver are still intact.

<p>
Sometimes it does the weird double-hump thing.  I suspect that only a single lamp fired.

<p>
Amp0's trigger transformer is a single primary and two secondaries.  I have OK results 
with two primaries in parallel, but there is nothing that keeps them balanced.  I'd 
like to do it in series, but then it doesn't like to trigger.

<h1>20180805</h1>

<p>
Replaced 4.7K resistors with 3.3 ohm resistors.  The trigger board still works.  (This
was an old error, I miss-read JK's schematic).

<p>
At amp1=2000V, it should achieve the same number of joules per cubic inch in Amp1 as in Amp0.
Except that for 130 mV (reading from the joulemeter) out of amp0, it achieves 32mV out
of amp1.  I believe the pump chamber is insufficiently reflective.  Stainless steel is
not known for its reflectivity, aluminum is much more reflective (and completely incompatible
with deionized water).  The illuminated volume is also quite a bit bigger on amp1 than amp0.

<h2>So, how can the pump chamber be improved?  </h2>

<p>
Pondering reflectiveness of stainless compared to aluminum, teflon, PVC, polystyrene.
The stainless is better than all of my other samples, despite what wikipedia says about
how reflective things should be.  I believe the surface finish is conflating the results.

<p>
6 inch piece of pipe, position flashlight and power meter to do a glancing reflection
off the inside of the pipe.  The stainless pipe is about 10 microwatts/cm^2, while the
PVC pipe is more like 3.5 microwatts/cm^2.  The PVC also noticeably leaks.

<p>
Then put the flat samples in the glancing reflection configuration.  Same result:
stainless is better than aluminum, teflon, and polystyrene.

<p>
The surface finish is too significant for my apparatus to make a meaningful comparison
between materials.

<h1>20180811</h1>

<p>
I acquired a 1.5 inch OD piece of stainless steel tubing, cut it to 6 inches, and then
mushed it with a vise to make a more or less elliptical pump chamber.  It is sized so that
its largest OD 
is the same is the ID of the 2 inch OD tube which is the pump chamber.  So this second
piece of tube sort of floats in the middle, completely submerged in coolant, and hopefully
reflecting more light from the lamps into the rod.  

<p>
I also painted a piece of PVC tubing with the gloss white paint I got to patch Square One.
It is significantly more opaque than the straight PVC.  It looks slightly brighter,
but the flashlight and power meter reflectance apparatus is inconclusive, the angle
dominates the measurement.

<p>
Other ideas include getting some alumina off ebay, and sticking it in the pump chamber
as diffuse reflectors above and below the rod and lamps.

<h1>20180812</h1>

<p>
Lamp OD on the oscillator is 9mm.

<p>
The trigger board ate itself again.  This is with all the 3.3 ohm resistors on the
anti-ring diodes.  The inductor is very low right now, but that was needed to get it
to fire reliably.  Even bigger SCR?

<p>
The new pump chamber improved things, 130 to 150 mv is now to about 70 mV, instead of 
36.  If the amp does not fire, its 21 mV.

<p>
The alignment laser is currently hitting the side of the rod mounting tube on amp1, but
the alignment laser is a little off, and larger than the real beam.  So I don't think 
its hitting the side of the rod.

<pre>
TN5050H-12WY 50A 1200V SCR  in a TO-247-3 package
TN3050G-12WY 30A  1200V  SCR     (the one we're using right now)

both are 200 A/u-sec and 1000V/u-sec

CS60-16io1	60A 1600V 

150 A/usec  and 1000V/usec
</pre>

<p>
What is the rise time?  LC circuit?

<p>
The trigger transformer has a ratio of 25.6 times (approx).  So the main pulse at
2000V will put a 78V current through the trigger board.  

<p>
A 325K resistor at 650V will conduct about 1.5 ma of current, which is about a watt.

<h1>20180818</h1>

<p>
I got the CS60-16io1 SCR.  I also realized that the PUT was incorrectly wired, which
is why it was triggering on the falling edge.  The trigger board got burnt by the
last "excursion", so I populated a new one (yay spares!).  I also increased the current limiting 
resistor to 10K (30W), and the 1K current limiting resistor to 5K (was 10K, but
it wasn't working, but that may have been the PUT error, but I haven't gone back
and tried it.  Either way, the new board actually runs at 600V, instead of 650V,
making me suspect that the zener diodes were being overwhelmed.

<p>
I got some 10uH extremely grunty inductors for the inductor on top of the SCR, however
it will not fire with the inductor in place.  5uH?  2uH?  0 uH seems to work...

<p>
I wonder if the PUT error caused the SCR failure.  

<p>
So I am stopping for now, with it actually sort of working (except for the gain
being 0.5 instead of greater than 1.0.).

<h1>20180819</h1>

<p>
Removed 6 turns from the 10uH inductor, resulting in a 3.5 uH inductor.
Didn't work.  Replaced with 0 uH inductor.  (Buying an expensive LCR meter
was a wise investment.)

<p>
Just the pump light is 16 mV of energy  (postit attenuated joulemeter).

<p>
2400, 1800, 2000 V (osc, amp0, amp1) 70 mV of energy output.  joulemeter 6
inches from amp1 same voltages, 19 inches from amp1, 60 mV of energy.

<h1>20180923</h1>

<p>
Pondering the voltages and currents of amp1 according to pfncalc1.xls.

<pre>
V	Ipk	Joules (both lamps)
1800	542	810
2000 	603	1000		<-- crosses blackbody
2200	663	1210
2400	723	1440		<-- crosses UV damage
2500	753	1562
2600	783	1690
2700	814	1822		<-- exceeds lamp rating (800A)
</pre>

<p>
The Do Not Exceed number is currently 2000V.  The arc goes opaque, and
thats pointless.

<p>
amp0 is 2400V max, 1440 joules.  I have other notes quoting 2900V (2102 J)
There was a calibration error in the previous control hardware revision,
so not sure what the correct value is.

<p>
amp0 lamp diameter is 9mm.  Maybe.  (measured at the electrode.)  So arc 
diameter is probably 7mm.

<p>
amp1 needs at least 1609 J (electrical) to achieve the same energy density
(J/cm^3 in the rod)) as amp0.  Which is well beyond UV damage threshold.

<p>
Want 350J/cm^3 of electrical input?  (solid state laser engineering)
So 3879 joules for amp1, to get 4.1 J/cm^3 stored energy.  We are Nowhere Near.
At 2000V, we are achieving 90 J/cm^3, which is off the bottom of the scale.


<h1>20180929</h1>

<p>
Goal is 4000 J of electrical input.  So 2000J/lamp, which is 4000V in a 250uF cap.

<p>
10 mm bore 150mm arc length has a mav voltage of 2500 to 3000V  (depending on the 
catalog you look at).  We need 4000V.  

<pre>
2000V in 500 uf is 1000 J	90 J/cm^3   (gain is <1)
2500V in 500 uf is 1562 J	140.9 J/cm^3
3000V in 500 uf is 2250 J	202 J/cm^3
3500V in 500 uf is 3062 J   	276 J/cm^3
4000V in 500 uf is 4000 J	360 J/cm^3
</pre>

<p>
rod is 11.08421 cm^3


<p>
amp0 is 2900V in 500uf = 2102 J = 145 J/cm^2	gain is surprisingly high
amp0's arc length is 200 mm, bore is probably 7 mm.

<p>
Bunch of observations:

<pre>
Amp1 has the alumina reflector.

coolant temp 24 C

joulemeter is 17 inches from amp1, just pump is joulemeter 3 mV 

2400 1800 2000    output 30mV joulemeter

2400 1900 2000	joulemeter 41 mV

2400 1800 ---  joulemeter 96, 98, 92 mV     (removed amp1)
2400 1900 ---  joulemeter 132 mV     (removed amp1)

2400 2000 --- joulemeter 175, 171, 173
2400 2100 --- joulemeter 218, 203, 208
2400 2400 --  joulemeter 310, 315, 308
2400 2500 --  joulemeter 332, 320, 343
2400 2600 --  joulemeter 347, 347, 351

moved the joulemeter, to determine how sensitive it is to position.
2400 2500 --  joulemeter 328, 332, 347


Observed gain with alumina diffuser is 41/175  


put amp1 back...
2400 2500 1500  joulemeter 88, 89, 93

2400 1800 1500  joulemeter 25, 23, 25
2400 1800 1800 joulemeter 24, 25, 24
2400 1800 2100 joulemeter 27, 25, 

evaluate timing...  

amp1 needs to be about 500 usec earlier.
delays were 100 500 300 100 100     (qswitch, osc, amp...)

try 100 4000 4500 100 100

firecomplete
decision at 0xec8f20a5  val= 0x8f81
min= 0x15a5  max= 0x2025  delta= 0xa80 341 usec
lamp 0  0xec8f1c68  0xec8f1e60  len 64 usec
lamp 1  0xec8f1dfd  0xec8f370b  len 815 usec
lamp 2  0xec8f2025  0xec8f409c  len 1056 usec
lamp 3  0xec8f15a5  0xec8f2e2d  len 798 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x2dfd actual 0xec8f2dfd 572 usec
rflags 0x8f fflags 0x8f 

Looks much better on oscilloscope  (which I trust more)

2400 1800 1900 joulemeter 32, 33, 32 
2400 1900 2000  joulemeter 44, 42, 41   gain 0.32

2400 2400 2000 joulemeter 127 124 127    gain 0.41

</pre>

<h1>20180930</h1>

<p>
Swapped amp1 back to the stainless steel reflector, since it works better.
The alumina was yellowed by the flash lamps.  Its darker yellow closer to
the lamp.  So the stainless steel definitely works better.

<p>
So I consulted the google, and alumina can be yellowed by UV, its caused by
iron and manganese, both of which are present in stainless steel.

<pre>
coolant temp 24 C
replaced stainless steel elliptical pump chamber
joulemeter is 17 inches from amp1, just pump is joulemeter 3 mV 

amp1 offset 2000, due to misfires

2400 2400 2000    joulemeter mv 100, 111, 107

which is worse than alumina reflector

2400 1900 2000	joulemeter mv 48, 49, 42

2400 1900 2100	joulemeter mv 53, 57, 59

amp1 offset to 1000

2400 1900 2100	joulemeter mv 55, 56, 54

amp1 offset to 3000
2400 1900 2100	joulemeter mv 43, 45, 44

amp1 offset to 500
2400 1900 2100	joulemeter mv 64, 67, 63

amp1 offset to 200
2400 1900 2100	joulemeter mv 63, miss, miss

so amp1 offset back to 500

amp0 offset 4000  from 4300
2400 1900 2100	joulemeter mv 54, 54, 55

amp0 offset 4500  from 4000
2400 1900 2100	joulemeter mv 55, 47, 47

amp0 offset 4300  from 4500
2400 1900 2100	joulemeter mv 42, 47, 50

</pre>

I want a 10mm bore, 150mm arc length xenon 450 torr.    (and a superluminal pony)

<pre>
Pondering CatalogueVQF...  DU series lamps,

7x152mm ...  VQX R 9P6 JA ?? 1 M
</pre>

<h1>20181014</h1>

<p>
So... new lamps.  Arc diameter is 10mm, arc length is 150mm, 
unfortunately its not cerium quartz.  They came from TJS, who
seem capable of doing business with individuals (so they will
get my business :-).  The lamps
do not match the drawings, there is a part number on the lamp
(TJS-1198), which does not match the box (TJS-1686).

<p>
So, who knows what they are...  I assume its xenon.

<p>
The new do not exceed number is 5100 Volts, which exceeds the
smaller capacitor's rating.  A 1500 Joule
pulse will be 3500 volts.  2000 Joules (per lamp) is 4000V.  

<p>
I get to fabricate new end caps for the pump chamber, and probably
new clamp tubes for the rod.  The new lamps are shorter, so the rod
will not be hanging quite as far out.

<h1>20181103</h1>

<p>
Fabricated a new pump chamber for the 10mm lamps.  The machining 
went quite a bit better than previous attempts.  Circles are still
smaller than they should be though.  Lots of assembly...  right now,
it is just the 2 inch tube, no inner reflector at all.

<pre>

Freerunning,  voltages 2400 1900 2100 
coolant 22 C  ambient 74 F

osc and amp0 only:   Joulemeter  134, 127, 129 mV 

with a single lamp and cap missfire, joulemeter 32

both lamps, joulemeter 48 mV  (probably)

</pre>

<p>
That 48 mV number is extremely close to the performance of the previous
chamber at the same voltage.  Which is encouraging, for the same amount
of energy in, its putting out the same energy.

<pre>
2500V missfire

2400 1900 2400   55mV		gain=0.42

2400 1900 2600  61, 58 mV	gain=0.46
2400 1900 2700  62, 64  mV	gain=0.48
2400 1900 2800  71  mV		gain=0.54

2400 1900 3000  74 71 32  mV	gain=0.56
2400 1900 3200  73 78   mV	gain=0.58
2400 1900 3300  75 75 80 mV	gain=0.59


missfire
2400 2400 fail  94 mv

2400 2400 3300 > 177 148  

loud pops from amp1 power supply...  and power dropoff...

2400 2400 3300 missfire  48 mV
2400 2400 3300 52 255 261 mV


At 3300V, that is over twice the energy of 2100V.
2100V is 1102 J, output of 48mV
3300V is 2722 J, output of 75mV.  
input ratio is 1 to 2.47,  output is 1 to 1.625  

</pre>

<p>
And the gain is STILL less than 1.  With nearly 3 times the input energy.
2722 J is 245 J/cm^3 in the rod.  The 350J/cm^3 number is 4000V

<p>
Try the alumina reflector?  That got a gain of 0.41 at 2000V

<p>
The trigger transformer (or something in the trigger circuitry) is 
uselessly unreliable.

<h1>20181110</h1>

<p>
Curve fitting the data from above...

data is:
<pre>
2400  0.42
2600  0.46
2700  0.48
2800  0.54
3000  0.56
3200  0.58
3300  0.59
</pre>

line is:
 x*0.00019395 -0.03556054
<p>
So gain=1.0 is at v=4972.  Which is too high, and pointless.  We need more than 1.0.

<p>
Constructed a terminal block for the GND point, the screw terminal things were stacked
too high and had problems with arcing or something.
Also bolted down the trigger transformers (with nylon and plexiglass hardware), Lorenz
forces were yanking them out of terminal blocks. (Thats an interesting problem to have.)
Redid the wiring for the trigger transformer primaries, but I don't expect that to
improve anything.
<p>
Also rebuilt the peltier heatsinks, so it can get down to 20 deg C now.  There are 
definite issues when the coolant gets warm (greater than 20 C).  The chiller is still
not especially capable, but its now more capable than the pump's energy input, and
will need a thermostat.

<p>
Cooler performance:

<p>
ambient is 72 F   (quite a bit lower than summer temps)

<p>
replaced second heatsink assembly with new copper heat spreader thing.
Temperatures from startup:

<pre>
11:07   21
11:08   21
11:09   20
11:10   20
11:12   20
11:15   20
11:18   20
11:24   19
11:30   19
11:38   19, thinking about 18
11:42   18
12:24   17 thinking about 16
12:36   16
12:41   16
12:52   16
13:01   16 thinking about 15
13:21   15
14:37   15 thinking about 14
14:54   14
15:28   14
15:48   14
16:51   14
17:32   14
</pre>

11:34  temps of the heat spreaders are 40C and 47C   (left, right)
The newer heatsink goo definitely works better.  Though left's airflow is better.

IMAGES:20181110

<h1>20181111</h1>

<p>
Put the alumina reflector, into new pump chamber with 10mm lamps.

<pre>
ambient 71F coolant temp 19 C
joulemeter 17" from amp1

2400 1900 2400  109 		gain=0.83
2400 1900 2600 104 102 100	gain=0.78
2400 1900 2800 114 112 		gain=0.87
2400 1900 3000 119 117 		gain=0.91
2400 1900 3200 124 		gain=0.95
</pre>
<p>
The alumina reflector approximately doubled the gain, as observed with the other lamps.
<p>
The trigger stills sucks a black vacuum.
<p>
ideas for reducing the trigger transformer's suck:

<pre>
Separate triggers for the two lamps.
	Test by driving only one lamp.
	complicated by possibly needing two voltage regulators.
	there is a fourth channel on the controller
vary turns on the primary.
	do we need more voltage or more current
move the secondary, to reduce the capacitor filtering the pulse out (not sure if thats happening).
	doesn't happen...  when the lamp is not ionized the trigger is completely isolated.
</pre>

<h1>20181118</h1>

<p>
coolant temp 19 degrees C.  Amp1 coolant temp unknown.

<pre>
2400 1900 3000 147 123 130	gain=1.02	joules=2250
2400 1900 3200 145 150 144     	gain=1.12	joules=2560     2x missfire timing failure 
2400 1900 3400 154 156 159	gain=1.20	joules=2890
</pre>

<p>
amp1 3600v took too long to charge

<p>
Having a solid GND on the pump chamber seems to have fixed the unreliable
triggering.  This is a bit of nod and smile...  

<p>
Coolant leak...  (which sounds so much more dramatic than the actual event)
The seal on the end of the rod leaked, and drooled coolant everywhere.
It had the wrong clamp tubes.  I replaced them with the right ones (713 mils long,
not 708) and labeled them better.

<p>
Large pulses spuriously trip the dump circuitry.  Induction into the
over-voltage boards?

<p>
This gain curve is steeper than the curve from 20181111.  Why?  My first theory is that the
coolant is cooler, so the osc and amp0 are happier.  But its the same temp.  The
joulemeter was moved, but recalibrating the amp0 only number requires moving amp1,
which is expensive.

<p>
There is spurious mode switch switching as well, while charging.  Rearranged the cables
a bit, to get the control lines away from the power lines.


moved the joulemeter...

<pre>
V=2400 1900 3400   134 140 

V=2400 2400 3400  405  409 409	gain=1.3

historic values:   2400 2400 --  joulemeter 310, 315, 308
</pre>

<p>
407 mV at 2.2V per joule is 0.185 Joules, with the postit.  So maybe 0.37 Joules,
the postit is historically a 50 percent attenuator, but don't have a calibration
point.

<p>
on 2017.10.21, with the old controller osc and amp got 322 mV with postit.  
amp0 might be good to 2900V, but at that point may be in opaque arc mode.

<p>
Put a lens in front of the amp, and tried it without the postit.  
Lots of miss-fires or something.  The image looked good, but the oscilloscope
didn't trigger.  Worked OK with a flash.  It did work a couple of times, on
the wrong scale, and got >970 mV.  So maybe > 440 mJ/pulse.

<p>
I trust the oscilloscope more than the laser right now, but it would have been
nice if the picture of the laser spot didn't look so consistent between miss-fires
and normals.

<p>
Without the postit, with diverging lens to avoid damaging sensor, freerunning,
timing may be poor.
Amp1 is not well aligned, the light is hitting the top of the tube or rod.

<pre>
2400 2400 3400    1752 1674 1726   or 0.780 J/pulse.
</pre>

<p>
Nothing to write home about, but I suspect thats the largest amount of energy
this laser has ever produced.

<p>
The coolant leak is back.  Through the rod clamps on the positive end.  It got
a droplet of water on the end of the rod, so the tube will probably have to
come off.

IMAGES:20181118

<h1>20181128</h1>

<p>
See line 3067 for historic power output numbers.

<h1>20181208</h1>

<p>
Fabricated new stainless steel pump chamber end caps.
Assembled with alumina reflectors.  Still getting UV damage with new lamps
(so not cerium doped).

<p>
Joule meter without postit, with diverging lens.  Laser free running, timing
not evaluated, alignment through the amp probably sub-optimal (its drooping).

<pre>
2400 2400 3400 joulemeter 1.576 miss 1.522 1.446  1.432 1.450 1.380  1.388  1.300  1.336  1.438

coolant temp 18.2 C  at end of tests
</pre>

<p>
Energies for above are 0.716 0.692 0.657 0.651 0.659 0.627 0.631 0.591 0.607 0.654
average is 1.427 volts or 0.649 joules

<p>
That is computed with the max voltage indication on the oscilloscope, it is
not integrated under the curve.  The gentec documentation for the correct
definition is ambiguous.

IMAGES:20191208

<h1>20181221</h1>

<p>
Lid extension segment dimensions.
<pre>
top  12 x 16 5/8  
sides 12 x 9
bottom  12 3/4 x 17 
strips 1 1/2 by 9, 1 1/2 by 16 1/8

1/4 round inset from the end 3/4 inch
need more 1/4 round.
</pre>

IMAGES:20191221

<h1>20181222</h1>

<p>
Added optical rail segment, and more carefully aligned amp1.
Still haven't done the timing.  Free running, not q-switched.

<pre>
V=2400 2400 3400	1.732 1.794 1.682  1.706 1.782
</pre>

<p>
avg energy is 1.7475 V,  or 0.794 joules

<p>
coolant temp 19.0 down to 18.2

<p>
The alignment laser is well centered, but the real beam is not, and is hitting
the top edge of the amp.

<h1>20181227</h1>

<p>
So if the unreliable triggering was addressed by grounding the pump chamber, does
that mean we can put the inductor on the top of the big SCR on the trigger board
back in?  That slows down the pulse, and is easier on the big SCR.

<h1>20190201</h1>

<p>
There is a bubble in the second amp ruby.  I don't remember seeing it before,
and it isn't visible in any of the old pictures.  Its not on the end of the
rod, its about 1/2 an inch from the output end.  

<p>
I've reversed the rod, so its 1/2 inch from the input side, so the energy
hitting it will be less.  Nothing to lose...

<p>
The osc beam profile is very multiple axial mode.  Not sure why.  The aperture
is 0.063 inches, it was historically 0.052, and I've made a new one but not
installed it yet.

<h1>20190209</h1>

<pre>
Walking the osc delay, to find the peak.  expect 0xf00, from historic performance.

osc v=2400

offset
oxc00	missfire
0xd00	11.18  12.12 12.82     avg 12.04 mV
0xe00  12.4 12.16  11.62	avg 12.06 mV
0xf00	10.58 11.52  12.38	avg 11.49 mV
0x1000	9.6  9.3  9.3		avg 9.4 mV

0xe00	12.92  12.54 13.6	avg 13.02 mV
0xf00	12.0  12.2  11.92	avg 12.04 mV

lets use 0xe00.  These numbers are extremely similar to the historic performance
on 20120505.  At least I didn't screw it up more...

after amp0...  walking amp0 offset  

Diffuse reflector in the beam (postit), joulemeter balanced on the pump chamber
enclosure, above it.  Its not an absolute measurement, but we're looking for relative.

4000	182 183 180		avg 181.6 mV

4800	201 191 202		avg 198.0 mV
5000	207.0 201 202		avg 203.3 mV
5100	188 212 188		avg 196.0 mV
5200	193.0  208.0 197	avg 199.3 mV
5400	195 193 200		avg 196.0 mV

Using 5000.  The peak is not dramatic.

On to amp1.  Joulemeter is in line, with postit on the front.

1000	270 missfire
1100	253 245 269		avg 255.6 mV
1200	269 269 270		avg 269.3 mV
1300	252 259 258		avg 253.3 mV
1600	237 264 257		avg 252.6 mV


using 1200  

</pre>

<p>
Then some absolute power measurements.  The joulemeter
was in line, angled to the beam so the spot was as spread
out as possible (still damaged the sensor).  There are a
whole bunch of pictures in 2019020901.

<pre>
qswitched
unattenuated  513 598  600	avg 570.3 mV  or 259 mJ

freerunning
unattenuated	944 974 985	avg 967.6 mV or 439 mJ

I was rather expecting more energy...  
</pre>

IMAGES:20190209

<h1>20190213</h1>

<pre>
Pondering things to try...

increase oscillator transverse mode aperture, to increase energy output.
	that energy may go into the higher modes though.
	diam  frac of 0.063 area     gain of second mode
	0.052 0.68		35.4%     		Works	frame 3648
	0.055 0.76    		31.3%			Works, I think  See frame 3649
	0.059 0.87		26.3%	min viable number is 25%
	0.063 1.00		21.8%   inches is too big, goes multi-mode		Multimode

osc voltage is already at the max value.

Increase amp0 voltage, to increase gain.
	May already be at point of diminishing returns due to blackbody problem.
	diminishing returns is at about 2800V, 2700V is about 30 percent brighter.

amp1 voltage can not be increased, 3400V already exceeds the recommended max.

Increase amp1 charge speed by reducing current limiting resistor.
	May exceed breaker limit.
	May increase energy output because less time for the caps to self-discharge
	on osc and amp0.
		Added instrumentation to observe the self-discharge
		the self-discharge is not amazingly significant.

Shorten amp1 pulse.
	Will require new pulse injection transformers.
	Already shorter than the fluorescence lifetime...  not sure if it will improve things.

Improve synchronization of the two lamps in amp1
	They really should be simultaneous...  :-P
	measure caps and inductors, get them more symmetrical, and possibly swap so
	the LC time of the two lamps is closer.
		caps are 230.1 and 254.9  uf  (gray, green respectively)
		inductors are 733 and 730 uH  (gray, green respectively)

		LC circuit is 1/2*pi*sqrt(L*C)

		LC time constant is .0025799343 and .0027156152 seconds (gray, green respectively)
		So allegedly green is delayed by 0.1 milliseconds, except that the delta is much larger than that.

		to reduce the offset, gray should be on 733.  And it is.  MEH.
		That is shorter than the delta I'm observing
		Add 67 uH inductor to gray circuit?

		Added 75 uH inductor to the gray circuit.  Nothing happened.  waveform was completely unchanged.
		Is it actually very under-damped, and ringing?  Measuring voltage on cap will answer that question.


</pre>

<h1>20190309</h1>

<p>
Fun with potting the trigger transformers:
<p>
Volume of the first layer is 42 ml.  Going for about 1/4 inch of material.
<p>
Volume of the coil is 70ml  (approx).
<p>
blue tape mold leaks patheticly.
<p>
amp0 lamps are 9mm OD
<p>
The new transformers seem quieter (acousticly).  The waveform is identical to before.

IMAGES:20190310

<h1>20190312</h1>

<pre>
frame 3819  2.9 mV voltages are 2400 2700 3400 freerunning  45 uJ cm^2

frame 3820 1.86 mV  voltages 2400 2700 3400 qswitched  29 uJ cm^2
</pre>

<h1>20190318</h1>

Some notation explanation, since this entry is nigh-gibberish...  I am walking the delay
of the qswitch after OSC flash lamp is observed, to find the maximum output of the oscillator.
Then I am walking the delay of the amp0 flash lamp around the osc flash lamp, to find the maximum output
of amp0.
<ul>
<li>The command to set the qswitch offset is "off 0 hex"  The 0 is the output channel.
<li>The command to set the flash lamp offset is "amp0 o 4600"  meaning amp0 flash lamp will be triggered 4600 clocks after T=0
<li>The lines with just a series of numbers are multiple pulse energy observations, millivolts output from joulemeter. 
</ul>


Walking the qswitch relative to observing the rising edge of the OSC flash lamp:
<pre>
after amp0

56.5 mv  qswitch missfire

rise jitter to 0x2000
433  411   >580  402  

off 0 f00

454 451 456  mv

off 0 1000

478  374 408 445      430  

significant pause between 478 and 374.  too cold?

significant delay...  and increase temp set point to 19.0 C

343  425  356 401 439 

pause...  temp at 19.0 C

339  327 332  421  423  321

rose to 19.4

set to 20 C
wait for a bit

at 19.7

409 393 319 348

temp set point increased to 20

pause... at 21.1

283  400 299 311 305    avg 319

off 0 e00
407  318 437   avg 387  

off 0 d00

408 428 416   avg 417  

off 0 c00

381 374 392     avg 392.3

off 0 d00

438 419 394   avg  avg 417
</pre>

Walk the offset of the amp0 flash lamp trigger relative to the osc flash lamp trigger:
<pre>

amp0 o 4600    (was 4200)

384 408 385   avg  392.3

amp0 o 4000   

395 410 428   avg  411  

amp0 o 4400

426 403 422  avg  417

</pre>

Walk the offset of the amp1 flash lamp trigger relative to the osc flash lamp trigger:

<pre>
moved sensor to after amp1
amp0 o 4200

520 429 517   agv 488  gain of 17%  not impressed

amp1 o 500

501 501 493   avg 498.3

amp1 o 10

522 526 538   avg 528.6  

osc o 5000
amp0 o 5000
amp1 o 800
dec 16f4
(should be unchanged )

549  537 519  avg  535
missfire 116 

amp1 o 400

526 503 550  avg  526  
missfire 110

amp1 o 600 

561  540 539  agv 546

wait a while. temp=20.1C

520 540 509  avg  523  

</pre>

Moved sensor to plate holder.

<pre>
ref beam 1.43 mV   3832

1.34mV  frame 3833   is 21 uJ/cm^2    (1.34/2.2 / 20.25 ) * 0.70

obj is 330 uV  is 7 uJ/cm^2     (330/2.2 / 20.25 )    frame 3834, 3835

ratio  3 to 1  want ref brighter...  it is

330 280 300  uV  

dropping temp to 18C

at 18.4
object only
450 470 430

unblocked ref    frame 3836

1170 990  uV   ref and obj,  about 26 uJ/cm^2

at 18.1 C

980 1230 800   990

replaced -179mm lens with -200mm lens on ref beam.

3630 3610 3580 3830     uV   frame 3843 3844     call it 56 uJ/cm^2

</pre>

so ref to obj 8:1   high but within U25 spec

<h1>20190323</h1>

Replaced alumina reflectors with mirror finish stainless steel.
Viton O rings on the body which are exposed to pump light are 
catastrophicly eroded.  See frames around 3854.

<pre>
joulemeter just after amp1 with tube diffuser.
voltages 2400 2700 3400 qswitched
447  490 434   avg 457 

Rather the opposite of better.  Though might be measurement noise.

9.81 + 10     45.7 (top)  11.37 (diameter)

so beam height is 9.81 + 10 + (45.7 - (11.37/2))  is 59.825 or 60mm with presumed measurement error

realign ALL THE THINGS...

ref beam is 3560 uV    55 uJ/cm^2    (3560 /2.2 / 20.25 ) * 0.70
frame 3899  
doesn't look like its covering 8x10

ref beam is 3270 uV   51 uJ/cm^2   

loud bang...  carbon on terminals to one of the lamps on amp1.  arced?  Lorenz forces keep
yanking connections out... (some problems are more interesting than others...)
bolt down all the things! with nylon hardware...

all light  2800 uV  44.0 uJ/cm^2
all light  2540 uV  39.9 uJ/cm^2

</pre>

IMAGES:20190323 

<h1>20190324 </h1>

Move the spatial filter back, since we're hitting the edge of amp1.

<pre>

before:
joulemeter after amp0, voltage 2400 2700 3400  freerunning
827 806  810 mV    avg 814.3
remove pinhole...
880 877 888 mV     avg 881.6

Move the lens to old pos...

818 785 814 mV    avg 805.6  

so loss of about 8 percent

amp1 enable
joulemeter moved to after amp1
pinhole still out

686  679  679     avg 681.3   

So amp1's gain is less than 1.  Though the sensor is not well calibrated (using the tube)

move sensor to plate holder, vertical
2490 2630 uV 

Test hologram made, number 167.1. first viable hologram on U25.
<p>
pondering inductors...
<p>
looking at amp1_3200V_single_underdamped_800mH.hpgl
The voltage goes past 0, all the way to 1200V, reversing the polarity on the lamp.
Sub-optimal...
Thats single lamp with 800 uH inductor.

IMAGES:20190324

</pre>

<h1>20190331</h1>
<p>
Fabricated two 330 mH trigger transformers.
<p>
They fire reliably only when a single one is connected.  When both are 
connected, it might be 1 in 5.  Tested with a single cap, but both lamps.
See amp1_3200V_single_underdamped_330uH_3.hpgl for a waveform.  Bounce
voltage is about 860 reverse polarity.
<p>
Reversed polarity of primaries of triggers.  (If it works on Star Trek...)
fired successfully 3 times in a row.  Then failed.
<p>
Put the polarity back.
<p>
Added a cap to the trigger board, for a total of 3.
<p>
For the Ukrainian rod, 5/16 inches diameter use 109 O rings, and 707 mil long clamp tubes.
The 3/8 rod uses 012 O rings and 714 mil clamp tubes.
<p>
The silicone O rings are too small.  Which is odd, since they are size 32.
So there was a gap, and coolant sprayed everywhere, and getting to take the pump
chamber completely apart and put it back together again.
Used the EDPM O rings instead, since they are the correct size.  (They also have not
significantly eroded as of 20190709, so EDPM seems to deal with the pump light.)
<p>
The trigger is still not reliable with 330 uH trigger transformers.
Added third cap.  What else can be done?  
<p>
Currently Ukrainian rod is installed.  Haven't actually let beam light hit it yet.

<h1>20190406</h1>
<p>
Installed the Ukrainian rod, put a 210 mil diameter aperture just up stream
to avoid reflections off interior of tubes, frame 3951.  There are striations
in the alignment beam (frame 3952 - 3954).  If they are present in the
real beam, it is unusable.  Only one amp1 lamp is hooked up.

V=2400 2700 3200  freerunning

amp1 didn't fire.  frame 3955
increased to V=2400 2700 3300
<p>
unplugged unused trigger transformer...  fired
<p>
frame 3957 striations are in real beam, and vertical not horizontal.  They
match the polarization of the respective lasers.  spurious beam is also present.
<p>
3958 and 3959 replaced the spatial filter and aligned to alignment laser.
<p>
3971, 3972 main beam through expanding lens, paper taped to input of amp0. <br>
3973 is alignment laser, 
<p>
3989  osc beam profile, magnified with lens, projected on paper by steering
mirror.  No sign of spurious beam.
<p>
3994 beam on first steering mirror.  extremely non-centered, and extra blob from
something on left side of mirror.  Feels like something closer to camera out
of focus.  Doesn't line up with anything, reflection off steering mirror?

<p>
Through frame 3989  OSC beam profile, are we hitting something in the steering
mirrors?  Spurious beam is not present after OSC, but IS after the steering mirrors.
<p>
3998 to 4003 alignment on input of amp0, magnified with lens
main beam aligned with alignment, on input of amp0.  yet spatial filter not aligned.

<p>
4004 output after amp1,  badly missing...  

<p>
4006 input of amp1, with bit of stuff reflecting off aperture.  

<p>
4010 output of amp1, no visible secondary beam.    <br>
4011 output of am1, now with visible secondary beam.

<p>
frame 4016 after amp1, V=2400 1800 3000 freerunning one lamp in amp1, spatial
filter in and aligned.  The striations are from the Ukrainian ruby.  Yay
technology.  Secondary beam is present but very subtle.

<pre>
V=2400 2700 3200   single lamp in amp1
</pre>
<p>
frame 4017 secondary beam appears.

<pre>
V=2400 2500 3200   single lamp in amp1
</pre>
<p>
frame 4018 reduced amp0 voltage no significant change in secondary beam <br>
frame 4019  pulled amp1 away from osc slightly.  secondary beam is not 
significantly changed, though main beam is.
<pre>
V=2400 2000 3200
</pre>
frame 4020 secondary beam still present.  But moved from 4019, a little
<pre>
V=2400 1800 3200
</pre>
frame 4021 secondary beam sufficiently reduced, but so is main beam.
<pre>
V=2400 2500 3200
</pre>
<p>
frame 4022  put voltages back  
<p>
frame 4032 removed pinhole
<p>
spatial filter lens X is 275 units
moved to X=270 units
<p>
frame 4023 to frame 4024 no significant change to secondary beam when spatial filter lens is moved.
<p>
The secondary beam is not significantly changed with the different amp1 rods?

<ul>
<li>frame 4025 to 4026, lifted the output end of amp1.
<li>frame 4027 alignment laser, with aperture on input of amp0
<li>frame 4028 alignment laser, removed aperture on input of amp0
<li>frame 4029, 4030 zappit paper on input of amp1, with alignment laser on too.
<li>frame 4032 amp0 output, enlarged slightly with -11mm lens.    V=2400 1800 3200
<li>frame 4033 V=2400 2500 3200
<li>frame 4036 amp0 output, much larger.  
<li> <pre> V=2400 2700 3200 </pre>
<li>frame 4037 amp0 output  
</ul>
<p>
The spurious reflection is definitely coming from amp1.  From the beam
inspection lens?  (Eventual theory is that its a reflection caused by
the rod C axis being 90 degrees off.)
<p>
The striations are definitely from the Ukrainian rod.  It is unusable.

IMAGES:20190406

<h1>20190407</h1>
<p>
Which way is the C axis oriented?
<p>
Placed a diffuse reflector behind amp0, and then stared at it a lot.
(do not look into laser with remaining eye.)
There is a double image side to side.  frame 4038.  Camera is looking
into side of laser, with bounce mirror  (first surface).
When the 3/8 inch rod is in that orientation, the blob is wider than tall.
In historic frame 3925, beam profile just after amp 1, the blob is taller
than wide.  
<p>
IE: the rod was installed 90 degrees off.

<h1>20190413</h1>

<p>
Frame 4044 is LED through Ukrainian rod.  It does not show the bifringence
of the 3/8" rod, or amp0.  

<p>
Putting the 3/8" rod back in...  correctly oriented.  (maybe...)
frame 4045 bifringence through 3/8 rod.  

<p>
frame 4049 V=2400 2500 3200  free running one lamp in amp1 
no significant stray beam.
<p>
frame 4052 V=2400 2600 3200 free running one lamp in amp1 output is 539 mV 245 mJ
<p>
Couple of test shots here with single lamp and 800 mH trigger transformers
Output was 226 mV.  Which is half of what the 330 mH trigger transformer did.
So, getting the 330 mH trigger transformers to reliably trigger may be Worth
The Trouble (tm).

<pre>
frame 4057 V=2400 2600 3200 free running both lamps  output pegged
frame 4058 1252 mV 
1330 1206 mV
avg 1262 mV  573 mJ
</pre>

<pre>
V=2400 2700 3200 qswitched both lamps 800 mH 1000 mV
</pre>

Moved joulemeter to plate holder.  3.2mV  ref beam is 50 uJ/cm^2.  U25 needs 30 uJ/cm^2.

IMAGES:20190413

<h1>20190414</h1>

<p>
Build a secondary trigger thing, to try and get both lamps to fire
with 330mH trigger transformers.

<pre>
V=2400 2600 3200 freerunning single lamp mode 4 368 390 396  mV
</pre>

frame 4070 is 396 mV sample

swapped lamps, to secondary trigger board.

<pre>
V=2400 2600 3200 freerunning single lamp mode 4 492 522 516 mV
</pre>

frame 4071 is 522 mV sample
<p>
The energy difference is from the caps...  brighter lamp is the 250 uF cap.
dimmer lamp s 230 uF cap.
<p>
And now: in stereo.  Both lamps connected.

<pre>
V=2400 2600 3200 freerunning both lamps mode 4 2230 2230 2245    avg=2235.0 1.015 Joules
</pre>
<p>
frame 4072 pegged joulemeter,  >1700 mV
<p>
So it has finally achieved the 1J it was allegedly capable of doing
before the whole second amplifier adventure.  (Found a sales brochure, it was actually
rated for 0.6 J.)

<p>
amp0 output is 1450 1450 1310 mV  avg=1403.3
<p>
So amp1 gain is about 1.59 times.  MEH.  But I'll take it.
<p>
moved joulemeter to plate holder.
<p>
frame 4089, 7.5 mV  or 117 uJ/cm^2   (7500 /2.2 / 20.25 ) * 0.70
free running... maybe 3/4 of that?
<p>
mode 5...

<pre>
V=2400 2700 3200 
</pre>
frame 4090 5.5 mV or 86.5 uJ/cm^2  qswitched
<p>
swapped -200mm lens for -179mm lens

<pre>
frame  4105  2340 uV  36 uJ cm^2
</pre>

IMAGES:20190414

<h1>20190420</h1>

<pre>
V=2400 2700 3200 freerunning both lamp mode 4 3620 3780 3720 uV  
</pre>
frame 4125 4126

<pre>
mode 5 qswitched

V=2400 2700 3200 qswitched both lamp mode 5 2720    42 uJ/cm^2
</pre>
frame 4129
<p>
osc only, free running is 24.5 mV  11 mJ  

<p>
put spatial filter pinhole back in
replaced ruby with new one.

IMAGES:20190420

<h1>20190421</h1>

<p>
frame 4223 alignment laser
<pre>
V=2400 2700 3200 freerunning  mode 4 
</pre>
<p>
frame 4224   ref beam set to minimum

IMAGES:20190421

<h1>20190428</h1>

<p>
The 12V battery charger creates an amazing amount of RF noise, interfering
with joulemeter.

<pre>
mode 5, V=2400 2700 3200 qswitched both lamps  ref only   2580 uV   38.9 uJ cm^2  frame 4231
</pre>

<p>
object about 10" from plate
joulemeter reads 2340 uV,  significant amplitude modulation

<p>
frame 4236  shadow check.  front of beaker is 10" from plate.
sound of high voltage leak while charging.

<p>
frame 4241 is hologram 168.1
<br>
frame 4242 is hologram 168.2

<p>
IMAGES:20190428

<h1>20190622</h1>
<p>
new capacitors, 830 uF rated, observed 807 and 824 uF.
<p>
firing single lamp...  outer lamp, closest to edge of board
2400 2700 1700 V   91 82 mV with attenuator freerunning
<p>
Firing other single lamp...  V=1700
<p>
(inner lamp, furthest from edge of board)
<p>
2400 2700 1700 V   77 77  76  mV with attenuator freerunning 

<p>
charge time is about 1500 millisec.
<p>
both lamps...
<p>
2400 2700 1700 V  425 414 
<p>
v=1900  (1480 J)
<p>
2400 2700 1900  V  821 833 


<h1>20190623  </h1>

<pre>
energy in ref beam only, freerunning

2400 2700 1900 5.12 5.37 5.23 mV

energy in ref beam only, qswitched

2400 2700 1900 3.66 4.00 4.21 mV   avg 3.956 mV  62 uJ/cm^2
</pre>

<h1>20190629</h1>

<p>
Measuring voltage in cap, to precisely measure pulse time,
to see how close we are to explosion energy...
<p>
amp1 circuit breaker tripped.

<p>
The 100:1 probe to the oscilloscope caused it.  
dump resistor was not warm after breaker pop, the caps were
apparently not charged at all.

<p>
Probe was incorrectly connected, and HV end of cap was
GNDed through the oscilloscope.  Yay circuit breakers.

<p>
V=2400 2700 1900
reported pulse length from qswitch trigger 1328 1331 1331  avg=1327.3 usec

<p>
observed with oscilloscope time to V=0: 1050 1040 1160   avg= 1083.3 useconds
(See hpgl in 20190629)

IMAGES:20190629

<p>
So we're going to call the pulse 1000 useconds long, which should put the
error on the safe side.

<pre>
Volts	Joules		percent of		J per cm^3	lifetime
	(825 uf)	Ee (spreadsheet)	(both lamps)	(pulses)
1700	1192		21.8			216.7		426007
1900	1489		27.2			270.7		64293
2000	1652		30.2			300.4		26588
2100	1819		33.2			330.7		11727
2200	1996		36.4			362.9		5326
</pre>

<p>
So, 2200V is just beyond the pointless point, assuming the 350 J/cm^3 rule of
thumb in Solid State Laser Engineering is valid (I believe my coupling
losses from lamp to rod are higher though).  33 percent of Ee is about
10^4 pulses.  Kinda hard on the lamps.

<p>
26 percent of Ee is 10^5 pulses.  
If the pulse is actually 1200 useconds long, V=2200 drops to 33 percent of Ee.
(not really significant)

<h1>20190707 </h1>

<pre>
V=2400 2700 2000   ref only qswitched  6220 uV  or 97uJ/cm^2.

Adjusting beam splitter down to get 30 uJ of ref.  (never gotten to do this before...)
about 1/2 way...
3660 uV  57 uJ cm^2
about 1/4 
1570 uV  24 uJ/cm^2

up a tad...
2100 uV= 33 uJ/cm^2
</pre>
Made hologram 173.1, yet another flower, on U25 in ultimate developer.  Not as bright as 
172.2, however looks very usable.

<h1>20191114</h1>

<a href="http://edweslystudio.com/Museums/Laser/JK/JKClub.html">JK Laser Club</a>


<h1>20191228</h1>

Rearranged the mechanical assembly of the power supply, so its actually
bolted togather.  Shortened wires to caps.  Still need to shorten the 
wires to the transformer, however I'm still debating how to connect
them.  Something detachable would simplify the disassembly for repairs etc.

Firing the caps seperately to verify that the trigger transformers are
still happy.  The cap on the yellow side has a fall time of 1.1 msec.

see yellow_cap_discharge.hpgl  and frame 5625 (and before)

switched to the other cap, which is now colorcoded red.

see red_cap_discharge.hpgl and frame 5629.  

it took a couple of trys to get the osc to trigger properly.  The
hold-off was too long, triggering as it charged, and then skipped
the discharge.

red cap's fall time is 1.16 msec, however that is determined by fiddling
with the cursors, so the precision is suspect at best.

Connected both caps, left the osciloscope on red cap.

frame 5620  
I am unconvinced the osc triggered.

frame 5621

definately triggered this time.  The charge cycle was extremely 
dramatic, as the voltage rose and it triggered.  
charge times were  1049 1735 3064 msec, to get to 1933 1730 1691 Volts
definately triggered this time

<h1>20191231</h1>

What is the actual output of the laser?
V=2300 2000 1800  pegged at 412mV   


V=2300 2000 1800 , joulemeter 1034 mV  freerunning
V 2400 2000 1800 , joulemeter 1354 mV freerunning  mode 3


V 2400 2700 2000 joulemeter  mode 4 joulemter pegged 1724 mV

sounded like it dammaged the joulemter as well.
added more holes to lens/etalon holder, and moved lens to cover
more of the sensor face.  frame 5635

osc didn't trigger

V 2400 2700 2000 joulemeter  mode 4 joulemter pegged 4310 mV

just barely pegged...  rescale osc to 500mV/div 

V 2400 2700 2000 joulemeter  mode 4 joulemter 4380 
frame 5637 4380 mV   1.99 J/pulse
frame 5638 4380 mV   1.99 J/pulse
frame 5639 4290 mV   1.95 J/pulse

Up from 0.6 J/pulse

Did the alignment thing,   up to frame 5683  which is the alignment laser

V= 2400 2000 1800   
frame 5684 was false start, camera was in LCD mode (it doesn't trigger the
flash then, for some reason.).
frame 5685  lid was off, so lots of pump light.



20200314

frame 5879 
3.75 mV     84 uJ/cm^2    normal to the ref,  so 65 uJ/cm^2 at 45 deg angle

decision at 0x7322d4f6  val= 0x8f81
min= 0xbe02  max= 0xcc20  delta= 0xe1e 459 usec
lamp 0  0x7322cafa  0x7322cbdc  len 28 usec
lamp 1  0x7322cc52  0x73230722  len 1914 usec
lamp 2  0x7322cc20  0x7322e7ae  len 896 usec
lamp 3  0x7322be02  0x7322e6ef  len 1332 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xd952 actual 0x7322d952 466 usec
rflags 0x8f fflags 0x8f 



frame 5880 
V=2400 2700 2000
offset= 0xd00 423 usec

decision at 0x0a4b77bd  val= 0x8f80
min= 0x60c9  max= 0x6f13  delta= 0xe4a 465 usec
lamp 0  0xa4b6db2  0x0  len -7344 usec
lamp 1  0xa4b6f13  0xa4ba9bc  len 1909 usec
lamp 2  0xa4b6edd  0xa4b8a87  len 900 usec
lamp 3  0xa4b60c9  0xa4b89d5  len 1336 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x7c13 actual 0x0a4b7c13 468 usec
rflags 0x8f fflags 0x8e 

oscilloscope amplitude was low,  was 50 mv/div, reduced to 10
osc lamp pulse looked like 700 usec long.

frame 5881
V=2400 2700 2000
offset 423 usec

decision at 0x73b21736  val= 0x8f80
min= 0x42  max= 0xe97  delta= 0xe55 466 usec
lamp 0  0x73b20d38  0x0  len -8528 usec
lamp 1  0x73b20e97  0x73b248d0  len 1895 usec
lamp 2  0x73b20e60  0x73b229fb  len 898 usec
lamp 3  0x73b20042  0x73b2293e  len 1334 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x1b97 actual 0x73b21b97 467 usec
rflags 0x8f fflags 0x8e 



osc flashlamp looks like 760 usec.  

frame 5882 qswitch missfire
V=2400 2700 2000
offset 423 usec
osc flashlamp looks like 780 usec.

firecomplete
decision at 0x0b28be94  val= 0x8e80
min= 0xa7a0  max= 0xb5f3  delta= 0xe53 466 usec
lamp 0  0x0  0x0  len 0 usec
lamp 1  0xb28b5f3  0xb28f0d5  len 1916 usec
lamp 2  0xb28b5c5  0xb28d1c4  len 911 usec
lamp 3  0xb28a7a0  0xb28d07a  len 1329 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch missfire


frame  5883
V=2400 2700 2000
offset 423 usec

qswitch missfire again

osc flashlamp looks like 760 usec.



frame 5884  
moved sensor to amp0

V=2400 2700 2000
offset 423 usec
amp0 length looks like 840 usec

decision at 0xd609512a  val= 0x8f80
min= 0x3a36  max= 0x4888  delta= 0xe52 466 usec
lamp 0  0xd6094735  0x0  len 504 usec
lamp 1  0xd6094888  0xd60982d9  len 1898 usec
lamp 2  0xd6094853  0xd6096410  len 902 usec
lamp 3  0xd6093a36  0xd6096318  len 1330 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x5588 actual 0xd6095588 466 usec
rflags 0x8f fflags 0x8e 

frame 5885
still looking at amp0

V=2400 2700 2000
offset 423 usec
amp0 length looks like  usec

qswitch missfire

firecomplete
decision at 0x2bf271fd  val= 0x8e80
min= 0x5b09  max= 0x6960  delta= 0xe57 466 usec
lamp 0  0x0  0x0  len 0 usec
lamp 1  0x2bf26960  0x2bf2a3e4  len 1904 usec
lamp 2  0x2bf26928  0x2bf28535  len 913 usec
lamp 3  0x2bf25b09  0x2bf283f2  len 1331 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch missfire



frame 5886

firecomplete
decision at 0x6291acb1  val= 0x8f80
min= 0x95bd  max= 0xa413  delta= 0xe56 466 usec
lamp 0  0x6291a2b4  0x0  len 24736 usec
lamp 1  0x6291a413  0x6291de52  len 1896 usec
lamp 2  0x6291a3df  0x6291bf7b  len 898 usec
lamp 3  0x629195bd  0x6291beb2  len 1333 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xb113 actual 0x6291b113 467 usec
rflags 0x8f fflags 0x8e 

still looking at amp0

V=2400 2700 2000
offset 423 usec
amp0 length looks like 800 usec

frame 5887

still looking at amp0

firecomplete
decision at 0xa3e3f089  val= 0x8f80
min= 0xd995  max= 0xe7e9  delta= 0xe54 466 usec
lamp 0  0xa3e3e68f  0x0  len 23904 usec
lamp 1  0xa3e3e7e9  0xa3e421e6  len 1887 usec
lamp 2  0xa3e3e7ba  0xa3e40389  len 905 usec
lamp 3  0xa3e3d995  0xa3e40284  len 1332 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xf4e9 actual 0xa3e3f4e9 467 usec
rflags 0x8f fflags 0x8e 

V=2400 2700 2000
offset 423 usec
amp0 length looks like 800 usec

frame 5888
moving to amp1

decision at 0x2bdefb98  val= 0x8f80
min= 0xe4a4  max= 0xf2f3  delta= 0xe4f 465 usec
lamp 0  0x2bdef19b  0x0  len -5792 usec
lamp 1  0x2bdef2f3  0x2bdf2d60  len 1901 usec
lamp 2  0x2bdef2c2  0x2bdf0eb2  len 909 usec
lamp 3  0x2bdee4a4  0x2bdf0da2  len 1334 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xfff3 actual 0x2bdefff3 466 usec
rflags 0x8f fflags 0x8e 

amp1 length looks like MEH
oscilloscope failed to trigger

frame 5889

amp1 length greater than 1800 usec, oscilloscope ran out of time.
rescaled...

firecomplete
decision at 0x6099c5e1  val= 0x8f80
min= 0xaeed  max= 0xbd3d  delta= 0xe50 465 usec
lamp 0  0x6099bbe1  0x0  len 29600 usec
lamp 1  0x6099bd3d  0x6099f7a6  len 1901 usec
lamp 2  0x6099bd08  0x6099d8cd  len 903 usec
lamp 3  0x6099aeed  0x6099d7e5  len 1333 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xca3d actual 0x6099ca3d 467 usec
rflags 0x8f fflags 0x8e 

frame 5890

firecomplete
decision at 0x98e88016  val= 0x8f80
min= 0x6922  max= 0x7776  delta= 0xe54 466 usec
lamp 0  0x98e8761d  0x0  len -9312 usec
lamp 1  0x98e87776  0x98e8b1ef  len 1903 usec
lamp 2  0x98e87745  0x98e89311  len 904 usec
lamp 3  0x98e86922  0x98e8920a  len 1331 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x8476 actual 0x98e88476 467 usec
rflags 0x8f fflags 0x8e 


oscilloscope failed to trigger (operator error)

frame 5891

firecomplete
decision at 0xc931a479  val= 0x8f80
min= 0x8d85  max= 0x9be0  delta= 0xe5b 467 usec
lamp 0  0xc9319a85  0x0  len 3752 usec
lamp 1  0xc9319be0  0xc931d5a0  len 1879 usec
lamp 2  0xc9319baa  0xc931b758  len 901 usec
lamp 3  0xc9318d85  0xc931b664  len 1330 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xa8e0 actual 0xc931a8e0 467 usec
rflags 0x8f fflags 0x8e 

amp1 looks like 1750 usec.

frame 5892

decision at 0x07029f3a  val= 0x8f80
min= 0x8846  max= 0x9699  delta= 0xe53 466 usec
lamp 0  0x702953d  0x0  len -12651 usec
lamp 1  0x7029699  0x702d099  len 1888 usec
lamp 2  0x7029665  0x702b24e  len 908 usec
lamp 3  0x7028846  0x702b123  len 1330 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xa399 actual 0x0702a399 467 usec
rflags 0x8f fflags 0x8e 

amp1 looks like 1950 usec.



Summarizing...

osc is 700 760 780 usec.    call it 850 usec.
amp0 is 840 800 800  usec.    call it 800 usec
amp1 is  1750 1950  usec.    call it 1850 usec.

So move amp1 earlier in time.  Does energy go up?

start at:
RAM configuration:
         Offset usec
  Qswitch 100  12
  Osc     5000  635
  Amp0    5000  635
  Amp1    600  76
  Amp2    100  12
        Voltage    max charge time (msec)
  Osc  0x04960 2400  2000
  Amp0 0x04a8c 2700  4500
  Amp1 0x047d0 2000  8000
  Amp2 0x047d0 2000  4000
Flags:  0x47  osc amp0 amp1 qswitch 
Fire Period:  0x1388 5000
Fire Delay fine:  0x0 0 usec
Fire Delay: 0 msec
State:  Off
            OSC    AMP0     AMP1     AMP2
Config Volt 2400    2700     2000     2000  Volts
Charge time 2000    4500     8000     4000  milliseconds
Offset      5000    5000      600      100  clocks
Set Point    -2      -2       -1       -1  Volts
Observed   1044    1263     1007     2964  Volts
            261     523      665     4639  Joules
Charging      N       N        N        N
Ready         N       N        N        N
Interlock  Fault
Current Mode: 5
state 0 target 0x0 actual 0x0 

5.46 5.36  5.36   mV

amp1 o 100

decision at 0x8ec8bcdd  val= 0x8f80
min= 0xa5e9  max= 0xb640  delta= 0x1057 531 usec
lamp 0  0x8ec8b4e4  0x0  len 27280 usec
lamp 1  0x8ec8b640  0x8ec8f061  len 1892 usec
lamp 2  0x8ec8b60a  0x8ec8d19a  len 897 usec
lamp 3  0x8ec8a5e9  0x8ec8ceb2  len 1327 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xc340 actual 0x8ec8c340 467 usec
rflags 0x8f fflags 0x8e 

firecomplete
decision at 0xcc9268aa  val= 0x8f80
min= 0x51b6  max= 0x61f3  delta= 0x103d 528 usec
lamp 0  0xcc92609b  0x0  len 6264 usec
lamp 1  0xcc9261f3  0xcc929c97  len 1908 usec
lamp 2  0xcc9261c4  0xcc927d26  len 891 usec
lamp 3  0xcc9251b6  0xcc927a76  len 1326 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x6ef3 actual 0xcc926ef3 466 usec
rflags 0x8f fflags 0x8e 

firecomplete
decision at 0xdecd94ce  val= 0x8f80
min= 0x7dda  max= 0x8e1d  delta= 0x1043 529 usec
lamp 0  0xdecd8cc2  0x0  len -23992 usec
lamp 1  0xdecd8e1d  0xdecdc833  len 1890 usec
lamp 2  0xdecd8de8  0xdecda950  len 892 usec
lamp 3  0xdecd7dda  0xdecda695  len 1325 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x9b1d actual 0xdecd9b1d 467 usec
rflags 0x8f fflags 0x8e 


5.31  5.42  5.48  mV

So not an especially significant delta, but only moved it 500 clock ticks.
move it further...  2500 clocks

Off>show
RAM configuration:
         Offset usec
  Qswitch 3100  394
  Osc     8000  1017
  Amp0    8000  1017
  Amp1    1000  127
  Amp2    100  12
        Voltage    max charge time (msec)
  Osc  0x04960 2400  2000
  Amp0 0x04a8c 2700  4500
  Amp1 0x047d0 2000  8000
  Amp2 0x047d0 2000  4000
Flags:  0x47  osc amp0 amp1 qswitch 
Fire Period:  0x1388 5000
Fire Delay fine:  0x0 0 usec
Fire Delay: 0 msec
State:  Off
            OSC    AMP0     AMP1     AMP2
Config Volt 2400    2700     2000     2000  Volts
Charge time 2000    4500     8000     4000  milliseconds
Offset      8000    8000     1000      100  clocks
Set Point    -2      -2       -1       -1  Volts
Observed   1007    1012      886     3018  Volts
            290     569      496     4488  Joules
Charging      N       N        N        N
Ready         N       N        N        N
Interlock  Fault
Current Mode: 5
state 0 target 0x0 actual 0x0 
Off>save
Saved in mode 5

frame 5893  
firecomplete
decision at 0x2156f182  val= 0x8880
min= 0xda8e  max= 0xf30e  delta= 0x1880 797 usec
lamp 0  0x2156f1b2  0x0  len -17976 usec
lamp 1  0x2156f30e  0x21572d6b  len 1899 usec
lamp 2  0x2156f2d8  0x21570f07  len 917 usec
lamp 3  0x2156da8e  0x21570385  len 1333 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch missfire


frame 5894  

firecomplete
decision at 0x38ffa464  val= 0x8880
min= 0x8d70  max= 0xa5f1  delta= 0x1881 797 usec
lamp 0  0x38ffa493  0x0  len -27744 usec
lamp 1  0x38ffa5f1  0x38ffe001  len 1890 usec
lamp 2  0x38ffa5bb  0x38ffc1dd  len 915 usec
lamp 3  0x38ff8d70  0x38ffb652  len 1330 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch missfire

frame 5895  


reconfig...

RAM configuration:
         Offset usec
  Qswitch 2100  267
  Osc     7000  890
  Amp0    7000  890
  Amp1    100  12
  Amp2    100  12
        Voltage    max charge time (msec)
  Osc  0x04960 2400  2000
  Amp0 0x04a8c 2700  4500
  Amp1 0x047d0 2000  8000
  Amp2 0x047d0 2000  4000
Flags:  0x47  osc amp0 amp1 qswitch 
Fire Period:  0x1388 5000
Fire Delay fine:  0x0 0 usec
Fire Delay: 0 msec
State:  Idle
            OSC    AMP0     AMP1     AMP2
Config Volt 2400    2700     2000     2000  Volts
Charge time 2000    4500     8000     4000  milliseconds
Offset      7000    7000      100      100  clocks
Set Point  1726    1726     1726       -1  Volts
Observed     86      52       79        0  Volts
              0       4        4        0  Joules
Charging      N       N        N        N
Ready         N       N        N        N
Interlock    OK
Current Mode: 5
state 0 target 0x0 actual 0x0 
Idle>save
Saved in mode 5


2 more missfires...
reconfig:
RAM configuration:
         Offset usec
  Qswitch 1100  139
  Osc     6000  762
  Amp0    6000  762
  Amp1    100  12
  Amp2    100  12
        Voltage    max charge time (msec)
  Osc  0x04960 2400  2000
  Amp0 0x04a8c 2700  4500
  Amp1 0x047d0 2000  8000
  Amp2 0x047d0 2000  4000
Flags:  0x47  osc amp0 amp1 qswitch 
Fire Period:  0x1388 5000
Fire Delay fine:  0x0 0 usec
Fire Delay: 0 msec
State:  Idle
            OSC    AMP0     AMP1     AMP2
Config Volt 2400    2700     2000     2000  Volts
Charge time 2000    4500     8000     4000  milliseconds
Offset      6000    6000      100      100  clocks
Set Point  1726    1726     1726       -1  Volts
Observed     31      70       91        9  Volts
              0       0        3        0  Joules
Charging      N       N        N        N
Ready         N       N        N        N
Interlock    OK
Current Mode: 5
state 0 target 0x0 actual 0x0 


frame 5898

firecomplete
decision at 0xa431f0a2  val= 0x8f80
min= 0xd9ae  max= 0xedf1  delta= 0x1443 659 usec
lamp 0  0xa431ec91  0x0  len 29072 usec
lamp 1  0xa431edf1  0xa4322802  len 1890 usec
lamp 2  0xa431edb6  0xa432090c  len 889 usec
lamp 3  0xa431d9ae  0xa4320276  len 1327 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xfaf1 actual 0xa431faf1 467 usec
rflags 0x8f fflags 0x8e 


frame 5899

firecomplete
decision at 0xc023bee0  val= 0x8f80
min= 0xa7ec  max= 0xbc31  delta= 0x1445 659 usec
lamp 0  0xc023bad5  0x0  len -13760 usec
lamp 1  0xc023bc31  0xc023f6b6  len 1904 usec
lamp 2  0xc023bbfb  0xc023d762  len 892 usec
lamp 3  0xc023a7ec  0xc023d0d2  len 1331 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xc931 actual 0xc023c931 467 usec
rflags 0x8f fflags 0x8e 


frame 5891   

firecomplete
decision at 0xe9fc5291  val= 0x8f81
min= 0x3b9d  max= 0x4fce  delta= 0x1431 657 usec
lamp 0  0xe9fc4e74  0xe9fc4fb0  len 40 usec
lamp 1  0xe9fc4fce  0xe9fc8a0a  len 1895 usec
lamp 2  0xe9fc4f9c  0xe9fc6b0a  len 892 usec
lamp 3  0xe9fc3b9d  0xe9fc6474  len 1329 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x5cce actual 0xe9fc5cce 467 usec
rflags 0x8f fflags 0x8f 

frame 5903   4.18 mV

decision at 0x41dd9686  val= 0x8f80
min= 0x7f92  max= 0x93c9  delta= 0x1437 658 usec
lamp 0  0x41dd926b  0x0  len -3920 usec
lamp 1  0x41dd93c9  0x41ddcd93  len 1881 usec
lamp 2  0x41dd9391  0x41ddaeff  len 892 usec
lamp 3  0x41dd7f92  0x41dda884  len 1332 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xa0c9 actual 0x41dda0c9 467 usec
rflags 0x8f fflags 0x8e 




5.76  5.76 4.18  mV


oscilloscope is not reliably triggering...

:off 0 d00  
423 usec

5.91 6.21 5.96   mV   avg 6.027

:off 0 e00  
455 usec

6.15 6.03 6.05   mV  avg 6.077

:off 0 f00
488 usec

6.33 6.32 6.24  mV  avg 6.297

:off 0 1000
520 usec

firecomplete
decision at 0xaa408330  val= 0x8f80
min= 0x6c3c  max= 0x808b  delta= 0x144f 661 usec
lamp 0  0xaa407f28  0x0  len 18224 usec
lamp 1  0xaa40808b  0xaa40ba76  len 1885 usec
lamp 2  0xaa40804d  0xaa409b2f  len 875 usec
lamp 3  0xaa406c3c  0xaa409503  len 1327 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x908b actual 0xaa40908b 565 usec
rflags 0x8f fflags 0x8e 

firecomplete
decision at 0xde670bac  val= 0x8f81
min= 0xf4b8  max= 0x901  delta= 0x1449 660 usec
lamp 0  0xde6807a7  0xde680918  len 46 usec
lamp 1  0xde680901  0xde6842e4  len 1884 usec
lamp 2  0xde6808d3  0xde6823a2  len 872 usec
lamp 3  0xde67f4b8  0xde681d81  len 1327 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x1901 actual 0xde681901 564 usec
rflags 0x8f fflags 0x8f 


6.3.88 5.64 5.85 mV  

back to 0xf00   488 usec

firecomplete
decision at 0xde670bac  val= 0x8f81
min= 0xf4b8  max= 0x901  delta= 0x1449 660 usec
lamp 0  0xde6807a7  0xde680918  len 46 usec
lamp 1  0xde680901  0xde6842e4  len 1884 usec
lamp 2  0xde6808d3  0xde6823a2  len 872 usec
lamp 3  0xde67f4b8  0xde681d81  len 1327 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x1901 actual 0xde681901 564 usec
rflags 0x8f fflags 0x8f 


firecomplete
decision at 0x39b3f03c  val= 0x8f80
min= 0xd948  max= 0xed9d  delta= 0x1455 661 usec
lamp 0  0x39b3ec43  0x0  len -22752 usec
lamp 1  0x39b3ed9d  0x39b4277d  len 1883 usec
lamp 2  0x39b3ed67  0x39b407fd  len 865 usec
lamp 3  0x39b3d948  0x39b401d4  len 1319 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xfc9d actual 0x39b3fc9d 532 usec
rflags 0x8f fflags 0x8e 

5.94 mV  6.23  6.26 6.058 mV

6.23 mV is 108.2 uJ/cm^2  We want about 30 uJ/cm^2 for U25.


20201003

The resonator is supposed to be doing 30 mJ, according to system 2000 marketing
material from Ed.  The aperature diameter is supposed to be 1.7 mm according to
Loic.  It is currently doing closer to 6 mJ, with 0.052 inch aperature.  

volume of resonator as a function of aperature diameter:
mm	inches	drill	volume(in^3)	ratio 
					to 0.052
1.3	0.052	55	0.0084		1.000
1.4	0.055	54	0.0095		1.131
1.5	0.059	53	0.0109		1.130
1.6	0.063  	52	0.0125		1.489		<-- largest single-mode according to spreadsheet
1.7	0.067	51	0.0141		1.678		<--- factory config according to Loic


See notes from 20171024 for discussion of transverse mode losses.  That analysis
says that larger that 1.63 mm will result in transverse multimode.  Notes from
20190213 indicate that it was multimode at 1.6 mm.  

20201011

See /home/bobdbob/mm/protius/stills/lab/20201011 for lots of recalibration
notes and images.

20201031

As per the varous experts, I have drilled the aperature out to 0.067 inches, 1.7 mm.

Next steps are to re-align the resonator yet again with the new advice.  The etalon
should go to the side, not up.  It should threshold at more like 1900 V.  


20201111

walking temperature of OC.
cavity etalon is temp controller 0
OC is temp controller 1
osc v 2000
302.9	303.2 275	11.0 13.3 19.65 15.05 9.25 16.30 15.30 13.85 26.3 14.65 20.45
303.9	303.9 283	3.80 10.55 2.6 2.6 2.95 6.25 2.5 2.4   basicly unusable
304.9	304.8 290	3.00 2.45 5.85 2.5 13.95 3.2 5.9 8.00 13.0 8.6 3.35 5.0 8.65 2.6 
305.9	305.9 298	9.65 5.50 13.15 3.0 12.0 2.7 8.2 2.8 2.7 2.5 2.5 2.8 2.6
306.9	306.9 305	6.9 5.8 4.5 17.0 9.8 12.7 6.9 13.06 12.5 11.5 10.3 9.9 11.75 7.96
307.9	hit failsafe

302.9 302.6 275		26.9 14.3 20.25 11.45 20.60 17.8 23.4 10.4 20.75 16.45 13.25
3018 301.8 268	15.4 20.25 11.75 18.6 12.85 7.6 12.8 13.1 11.35 14.75 13.15
2998 3002 260	2.5 2.15 2.95 2.95 2.8 3.0 8.55 2.45 8.3 5.15 2.3
3025 

There is a bug in the kelvin/DAC conversion which causes quantization to
1 degree K.  fixed on 20201111  however that date is not shown in the
help string.

300.9 300.9 268	2.45 2.8 2.45   basicly all 2.4 or so
301.8 3020 276	7.9 9.4 10.5 15.85 -- 12.25 11.45 5.9 7.35 9.2 2.35 7.06 10.1
302.4 302.4 279	26.25 16.85 15.7 17.2 12.2 21.6 6.05 7.8 15.5 6.7 16.5
308.8 309.0 328	3,15 7.35 6.65 14.0 7.3 2.8 -- 10.6 3.0 2.7 -- 2.8 -- 


cavity etlon is once more normal to the beam.
top=5+50+6  side=6+0+42

reduce side by 0.3mm    6+0+12

It seems much harder to get adjusted when the side micrometer is used...

20201122

OC is 302.9 K
CE is 302.9 K

CE 301.9  9.7 8.5 11.8 8.9 13.15 9.0 5.7 7.5 4.8 8.6
CE 302.4  13.0 16.25 16.05 14.45 18.5 24.8 26.3 28.35 28.25 13.05 

CE 302.9  21.4 19.0 19.15 22.6 27.4 26.3 31.1 25.35 31.10
CE 303.3  14.55 21.45 24.85 19.75 28.8 21.15 18.05 24.1 14.5 16.35 14.95
CE 303.8  15.2 16.75 18.45 19.55 15.7 16.3 19.75 14.4 18.55 14.55 
CE 304.3  8.4 10.55 12.3 11.0 12.55 8.75 13.55 7.7 14.3 9.55
CE 304.8  9.55 2.9 2.9 3.0 3.0   fail.

CE 301.9 stats 4.8 8.765 2.49889 13.15 (min, mean, stddev, max) 
CE 302.4 stats 13.0 19.9 6.32838 28.35 (min, mean, stddev, max) 
CE 302.9 stats 19.0 24.8222 4.61858 31.1 (min, mean, stddev, max) 
CE 303.3 stats 14.5 19.8636 4.72901 28.8 (min, mean, stddev, max) 
CE 303.8 stats 14.4 16.92 2.02075 19.75 (min, mean, stddev, max) 
CE 304.3 stats 7.7 10.865 2.26863 14.3 (min, mean, stddev, max) 

coolant temp is actually 19C according to a thermometer, the thermostat 
is not especially calibrated.
Increased set point to 21C, to see what happens.  The observation is
that in a series of shots, the power tends to go up.

CE 302.9  20.6 24.75 14.95 13.15 9.1 13.7 14.1 17.35 23.55 12.5 
stats 9.1 16.375 5.08949 24.75 (min, mean, stddev, max) 

after warming coolant up to indicated 21C:

CE 302.9  24.4 28.45 27.1 32.2 27.9 24.8 37.3 24.8 36.9 21.9
stats  21.9 28.575 5.28842 37.3 (min, mean, stddev, max) 

Lets try coolant indicated temp of 22C

indicated 21.5C:
CE 302.9  17.45 23.25 31.65 26.25 27.3 21.4 26.3 26.8 29.9 25.2
stats 17.45 25.55 4.08323 31.65 (min, mean, stddev, max) 

indicated 22.2C:
CE 302.9  21.0 20.7 21.45 17.25 14.55 22.85 17.05 21.9 28.1 20.4
stats 14.55 20.525 3.71642 28.1 (min, mean, stddev, max) 

The beam profile is terrible.  As if something is obstructing the
resonator.  Basicly unusable.  Realign from the top?

20201126

CE normal to beam at top= 5+50+8  side= 6+0+42

Moved the OC, so numbers will be different...

20201126
frame 2 to 10 is the osc with no cavity etalon.  Just the OC

frame 12 and 13 are after tightening some bolts and moving energy sensor
in front of OC.
bumped lens...  frame 14-20 are osc with no cavity etalon.

put in CE, and tuned for max power.  mV=27.0 V=2100 top=5+50+4 side=6+0+38

frames 21 to 30 are the osc with the CE square to beam, and card between
CE and PC.

frame 34, 35   is side= 6+0+6
frame 36, 37   is side= 6+0+4
frame 38, 39   side=6+0+0
frame 40, 41  side=6+0+10
frame 42, 43  side=6+0+20

corrected reading  5+50+40   (10 less than old 6+0+0)

frame 44  missfire, relay tripped
frame 45, should have been light...

frame 46  side-5+50+0
frame 47 side=5+50+45

frame 64  side=


realigned normal to beam.  side=6+0+38  ish.

moved to +8, and then walked the power up, to +39  which was pointless.

frame 67 - card between CE and PC.

20201206

Found some FC-770 florinert, which is the replacement for FC-77, and put
it in the pockels cell.  It was completely dry.
I used a HeNe laser to measure the loss through the pockels cell before and
after filling it with FC-770.  Before the PC attenuated 2.00 mW to 1.5 mW.
After being filled it attenuated 2.00 mW to 1.77 to 1.82 mW.  Which
is a significant improvement.

Once again... alignment from the top...  Because putting the PC back in 
completely eliminated lasing.  Even when adjusted to lase (no cavity etalon,
no mode selection aperature).

Adjusted cavity etalon to be normal to the beam, top= 5+50+3  side= 6+0+40.
The power was all over the place, I believe due to shifting temperatures.
Osc V=2000, which is lower than previous attempts.

Reduced side micrometer to read 6+0+10.

Oscillator was observed doing 25.9 mJ free running.  Failed to record the
voltage.


All up, V=2100 1900 1700  output is 114 319 109 269   mV

prior full power settings are V=2400 2700 2000    (2000, 340, 8000 msec)

V= 2100 1900 1800  output is 347 407 413 
attenuated with a piece of paper: 97 75 83  the correction factor is 4.5.

V= 2200 1900 1800  attenuated output is 347 407 413  151  147 mV

V= 2300 1900 1800 attenuated output 147  177 165

V= 2300 2100 1800  attenuated output 280 280 272   (about 572 mJ)

V= 2300 2300 1800  attenuated output 330 373 349 

V= 2400 2300 1800  attenuated output  397 412 411  (about 830 mJ)

OSC only, free running
V	mV
2100	9 11 8.5 9.1	 mV	avg=9.4   4.27 mJ
2200	23.1 27.5 26.5 27.2 mV	avg=26.0  11.85 mJ
2300	41.2 41.1 45.1 42.0 mV	avg=42.35 19.25 mJ
2400	60 59 58.5 61.5  mV	avg=59.65 27 mJ

(this line is almost perfectly linear)

<h1>20201212</h1>

D010.PLT is the oscillator free-running on the new oscilloscope.
kinda fuzzy, but the multiple pulses are visible.

D011.plt is a slightly better shot, repositioned the sensor to be looking
down at the postit on the optical rail.  Also sc1.000 and sc1001.txt 
V=2200  osc at 5200 (661 usec)

The pump flash is 680 usec long, from the trigger pulse to end of light.
last lasing was at 608 first lasing was at 407 usec from trigger.
light appeared at 37 usec, steady state at about 205.  

p006.pnl is the config for the det10a sensor.

fired the osc again, D012.plt  
free-running pulses are 9.29 usec apart, and about 0.8 usec long.
See D013.plt.
Joulemeter read 39.7 mV or 18 mJ.
Firing>
firecomplete
decision at 0xb3ec8855  val= 0x180
min= 0x95ec  max= 0x95ec  delta= 0x0 0 usec
lamp 0  0xb3ec8055  0xb3ed808f  len 8340 usec
lamp 1  0xb3ec95ec  0xb3ece27a  len 2492 usec
lamp 2  0x0  0x0  len 0 usec
lamp 3  0x0  0x0  len 0 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch missfire

decision is based on first pulse, which will be from the main controller.
So decision at about 1000 usec from that time base.
current (old-ish) timing is:
         Offset usec
  Qswitch 100  12
  Osc     5200  661
  Amp0    5000  635
  Amp1    1200  152
  Amp2    100  12

increasing osc v to 2300, so see how that affects the waveform.

fire V= 2246 4 0 9

Firing>
firecomplete
decision at 0x36fd72a2  val= 0x8380
min= 0x6823  max= 0x6823  delta= 0x0 0 usec
lamp 0  0x36fd52a2  0x36fe52e3  len 8341 usec
lamp 1  0x36fd6823  0x36fdb7fa  len 2598 usec
lamp 2  0x0  0x0  len 0 usec
lamp 3  0x0  0x0  len 0 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x77c3 actual 0x36fd77c3 1208 usec
rflags 0x83 fflags 0x83 

Data  in sc1002.txt

osc v=2100
data in sc1003.txt 

osc v=2000
data in sc1005.txt  and d014.plt

Aligned spatial filter...  attenuating 20 mV to about 17 mV.

look at waveform after amp0:
configured voltages are 2100 2400 

fire V= 2054 2349 36 20

Firing>
firecomplete
decision at 0x97cbf8fd  val= 0x8780
min= 0xedb4  max= 0xeea6  delta= 0xf2 30 usec
lamp 0  0x97cbd8fd  0x97ccd94b  len 8343 usec
lamp 1  0x97cbeea6  0x97cc3926  len 2425 usec
lamp 2  0x97cbedb4  0x97cc08d3  len 882 usec
lamp 3  0x0  0x0  len 0 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xfe46 actual 0x97cbfe46 1213 usec
rflags 0x87 fflags 0x87 

Data in sc1006.txt  
amp0 pump light is maybe 660 usec long.  

OSC fires at t+661  amp0 fires at t+635
energy was 860 mV or 390 mJ

Walking amp0 voltage:
osc v 2100 , output after spatial filter is about 17 mV

amp0 v=2400   energy= 860 894
amp0 v=2500  904 904 946 
amp0 v=2600 1010 1080
amp0 v=2700 1012 962

So amp0's gain is about 52 to 58 times.  The output does not increase 
significantly with the energy in.  So hypotheticly the amp is saturated
at v=2500 or v=2600, and the 17mV coming into it can not extract any
more energy than it is.


investigate pulse length of amp1:

V= 2100 2500 1800

energy 962 mV  gain of amp1 is basicly 1

V= 2100 2500 1900

energy 1420 mV  gain of 1.5  

fire V= 2027 2459 1894 15

Firing>
firecomplete
decision at 0x08e2f923  val= 0x8f80
min= 0xd923  max= 0xe589  delta= 0xc66 403 usec
lamp 0  0x8e2e403  0x8e4d024  len 16019 usec
lamp 1  0x8e2e589  0x8e32eed  len 2389 usec
lamp 2  0x8e2e47d  0x8e2ff90  len 881 usec
lamp 3  0x8e2d923  0x8e302e9  len 1359 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xf529 actual 0x08e3f529 558 usec
rflags 0x8f fflags 0x8f 

pulse length is about 1500  usec

fire V= 2027 2427 1862 4

Firing>
firecomplete
decision at 0x53ce2676  val= 0x8f80
min= 0xfdf  max= 0x1c2f  delta= 0xc50 400 usec
lamp 0  0x53ce0676  0x53cf06bd  len 8342 usec
lamp 1  0x53ce1c2f  0x53ce648c  len 2355 usec
lamp 2  0x53ce1b27  0x53ce360d  len 875 usec
lamp 3  0x53ce0fdf  0x53ce39d1  len 1365 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x2bcf actual 0x53ce2bcf 1215 usec
rflags 0x8f fflags 0x8f 

see file sc1007.txt and d015.plt and d016.plt

amp1 moved 600 samples earlier in time, since its pulse is so long.

V=2100 2500 1900
time= 100 5200 5000 600 

energy=1530 mV
image in sc1008.txt

fire V= 1999 2399 1894 9

Firing>
firecomplete
decision at 0x57a2072d  val= 0x8f80
min= 0xee35  max= 0xfcee  delta= 0xeb9 479 usec
lamp 0  0x57a2e72d  0x57a3e781  len 8344 usec
lamp 1  0x57a2fcee  0x57a345cf  len 2372 usec
lamp 2  0x57a2fbe0  0x57a316e9  len 880 usec
lamp 3  0x57a2ee35  0x57a31809  len 1361 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xc8e actual 0x57a30c8e 1216 usec
rflags 0x8f fflags 0x8f 

amp1 moved even earlier, to t+200 clocks
V=2100 2500 1900
time= 100 5200 5000 200 

energy= 1530
image lost, osc retriggered

fire V= 2063 2431 1846 4

Firing>
firecomplete
decision at 0xdfa75e74  val= 0x8f80
min= 0x43ea  max= 0x5428  delta= 0x103e 528 usec
lamp 0  0xdfa73e74  0xdfa83eac  len 8340 usec
lamp 1  0xdfa75428  0xdfa79d93  len 2389 usec
lamp 2  0xdfa75320  0xdfa76e14  len 877 usec
lamp 3  0xdfa743ea  0xdfa76d91  len 1355 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x63c8 actual 0xdfa763c8 1215 usec
rflags 0x8f fflags 0x8f 

repeat:

energy detector didn't trigger
image in sc1009.txt 

fire V= 2063 2431 1846 4

Firing>
firecomplete
decision at 0xdfa75e74  val= 0x8f80
min= 0x43ea  max= 0x5428  delta= 0x103e 528 usec
lamp 0  0xdfa73e74  0xdfa83eac  len 8340 usec
lamp 1  0xdfa75428  0xdfa79d93  len 2389 usec
lamp 2  0xdfa75320  0xdfa76e14  len 877 usec
lamp 3  0xdfa743ea  0xdfa76d91  len 1355 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x63c8 actual 0xdfa763c8 1215 usec
rflags 0x8f fflags 0x8f 


amp1 voltage ramp:
V=2100 2500 1900 
time= 100 5200 5000 200

v=1900 energy=1.698 mV
v=2000 energy=2.235 mV

increase osc power...

V=2300 2500 2000

image in sc1001.txt  

energy didn't trigger?

fire V= 2212 2411 1972 36

Firing>
firecomplete
decision at 0x0c8cec1f  val= 0x8f80
min= 0xd141  max= 0xe1ac  delta= 0x106b 534 usec
lamp 0  0xc8ccc1f  0xc8dcc6c  len 8343 usec
lamp 1  0xc8ce1ac  0xc8d304b  len 2559 usec
lamp 2  0xc8ce0c9  0xc8cfb69  len 866 usec
lamp 3  0xc8cd141  0xc8cfa5b  len 1337 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xf14c actual 0x0c8cf14c 1210 usec
rflags 0x8f fflags 0x8f 

retry...

failed again...  energy meter didn't trigger.

reduce to osc v 2100.  energy= 2.685 mV   

V=2200 2500 2000

still no energy trigger.  sound is different...  

try qswitching...
V=2100 2500 2000
time=100 5200 5000 200

energy = 1.49 mV  
image in SC1002.txt 
coolant temp 21.2 C  indicated   (subtract 1 deg for actual value)

fire V= 2047 2459 1976 15

sound very sharp.

Firing>>
firecomplete
decision at 0xe44ac62f  val= 0x8f80
min= 0xab44  max= 0xbbde  delta= 0x109a 540 usec
lamp 0  0xe44aa62f  0xe44ba663  len 8339 usec
lamp 1  0xe44abbde  0xe44b056c  len 2394 usec
lamp 2  0xe44abad9  0xe44ad55a  len 862 usec
lamp 3  0xe44aab44  0xe44ad46e  len 1339 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xcb7e actual 0xe44acb7e 1214 usec
rflags 0x8f fflags 0x8f 



osc only, V=2400 pushing 57 mV after the spatial filter.  Seems aligned.  


bunch of verifying alignment of pulsed apparatus.
No Diffusers!
sc1003.txt is the pulse observed with det10a at film plane.
Qswitched 
V= 2300 2500 2000
time= 100 5200 5000 200 100



osc ready time= 1246  V= 2200
osc ready time= 1246  V= 2212
amp0 ready time= 2630  V= 2399
osc ready time= 1246  V= 2191
amp0 ready time= 2630  V= 2415
amp1 ready time= 3831  V= 1956
Ready!
remote Fire!
>
firecomplete
decision at 0x54d22d00  val= 0x8f80
min= 0x1233  max= 0x2291  delta= 0x105e 532 usec
lamp 0  0x54d20d00  0x54d30d40  len 8341 usec
lamp 1  0x54d22291  0x54d27048  len 2529 usec
lamp 2  0x54d22188  0x54d24477  len 1137 usec
lamp 3  0x54d21233  0x54d23b70  len 1342 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x3231 actual 0x54d23231 1210 usec
rflags 0x8f fflags 0x8f 



at V=2100 2500 2000
ref beam is 1.18 or 1.45 mV  / 2.2 * 20.25 * cos(45) = 18 uJ/cm^2

at V=2300 2500 2000:
1.84 1.62 mV  avg= 1.73 / 2.2 * 20.25 = 38 uJ/cm^2 = 27 uJ/cm^2


hologram 207.1:

remote Fire!
osc ready time= 1289  V= 2200
osc ready time= 1289  V= 2191
amp0 ready time= 2702  V= 2383
osc ready time= 1289  V= 2219
amp0 ready time= 2702  V= 2376
amp1 ready time= 3936  V= 1972
Ready!
remote Fire!
>
firecomplete
decision at 0xdc98c0c6  val= 0x8f80
min= 0xa5f4  max= 0xb65a  delta= 0x1066 533 usec
lamp 0  0xdc98a0c6  0xdc99a108  len 8341 usec
lamp 1  0xdc98b65a  0xdc9903cb  len 2520 usec
lamp 2  0xdc98b54f  0xdc98d864  len 1141 usec
lamp 3  0xdc98a5f4  0xdc98cf4d  len 1345 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0xc5fa actual 0xdc98c5fa 1211 usec
rflags 0x8f fflags 0x8f 

RAM configuration:
         Offset usec
  Qswitch 100  12
  Osc     5200  661
  Amp0    5000  635
  Amp1    200  25
  Amp2    100  12
        Voltage    max charge time (msec)
  Osc  0x048fc 2300  2000
  Amp0 0x049c4 2500  3500
  Amp1 0x047d0 2000  4500
  Amp2 0x04960 2400  2500
Flags:  0x47  osc amp0 amp1 qswitch 
Fire Period:  0x1388 5000
Fire Delay fine:  0x0 0 usec
Fire Delay: 0 msec
State:  Off
            OSC    AMP0     AMP1     AMP2
Config Volt 2300    2500     2000     2400  Volts
Charge time 2000    3500     4500     2500  milliseconds
Offset      5200    5000      200      100  clocks
Set Point    -2      -2       -1       -1  Volts
Observed    984     991     1012     2991  Volts
            248     484      523     4617  Joules
Charging      N       N        N        N
Ready         N       N        N        N
Interlock    OK
Current Mode: 5
state 0 target 0x0 actual 0x0 


hologram 207.2:

remote Fire!
osc ready time= 1279  V= 2212
osc ready time= 1279  V= 2212
amp0 ready time= 2706  V= 2388
osc ready time= 1279  V= 2246
amp0 ready time= 2706  V= 2427
amp1 ready time= 3969  V= 1944
Ready!
remote Fire!
>
firecomplete
decision at 0xc13a4d7b  val= 0x8f80
min= 0x32a9  max= 0x430e  delta= 0x1065 533 usec
lamp 0  0xc13a2d7b  0xc13b2db4  len 8340 usec
lamp 1  0xc13a430e  0xc13a90b3  len 2527 usec
lamp 2  0xc13a4202  0xc13a64ea  len 1136 usec
lamp 3  0xc13a32a9  0xc13a5bc9  len 1338 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x52ae actual 0xc13a52ae 1210 usec
rflags 0x8f fflags 0x8f 

hologram 207.3

frame 8726

osc ready time= 1247  V= 2235
osc ready time= 1247  V= 2239
amp0 ready time= 2645  V= 2427
osc ready time= 1247  V= 2235
amp0 ready time= 2645  V= 2427
amp1 ready time= 3894  V= 1988
Ready!
remote Fire!
>
firecomplete
decision at 0x35d76df4  val= 0x8f80
min= 0x530f  max= 0x637f  delta= 0x1070 535 usec
lamp 0  0x35d74df4  0x35d84e31  len 8341 usec
lamp 1  0x35d7637f  0x35d7b157  len 2533 usec
lamp 2  0x35d7627a  0x35d7856b  len 1137 usec
lamp 3  0x35d7530f  0x35d77c27  len 1337 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x731f actual 0x35d7731f 1209 usec
rflags 0x8f fflags 0x8f 


2020.12.19

Lets try to optimize the angle of the cavity etalon, and the pockels cell.

starting positions:
CE: top = 5+50+1.5  side= 5+50+10
pockels cell: 5+50+16.5  side= 5+50+18

first, the CE.  Removing the mode selection aperature, since this is
primarily a question of frequency.  

coolant temp 19.6 C indicated  (poor calibration)

varying side position:
5+50+10		13.24 10.0 11.92   
excessive variance of the power.  some shots are 1/2 the ~10 mV number.

How about rotating pockels cell, and observing beam profile?  The pockels
cell is aligned to the alignment laser, not the actual laser, without the
mode selection aperature, I expect the maltise cross to be dramaticly visible.


Back to dinking with the CE...

varying side position:
V=2100 with attenuator
5+0+33		1.7 1.9 
5+0+36		2.1 2.4 2.7 
5+0+39		2.3 1.7 
5+0+42		3.4 3.45 4.2
5+0+45		7.9 4.5 5.2
5+0+48		6.75 6.9 6.7
5+50+1		7.6 10.05 9.95
5+50+4		8.5 8.2 7.6 
5+50+7		14.8 10.9 14.75 10.5

5+50+10		16.25 17.9 15.35 15.36	avg 16.22	<--- starting point
+13		20.45 18.60 15.65 17.65 avg 18.08
+16		16.85 16.55 18.35 18.70  avg 17.62
+19		18.3 23.2 18.9 17.25  19.42


+13		16.05 18.1 17.45 16.25  avg 16.97

28.4 mV V=2200 no attenuation  about what we were getting on 2020.12.06
coolant temp 21.0   12 mJ 
28.6 28.45 32.4  32.45 32.35   

V=2300  50.1 53.0 52.7 avg 51.93 mV  23.6 mJ
V=2400 69.2 73.0 77.3 avg 73.16 mV   33.2 mJ


20201220

V=2300 2500 2000 free running
	2.94 mV with room lights on.
	2.6 2.62 2.74  mV room lights off

measured with lecroy:
config is in p007.pnl   
example image in d007.plt
	2.81 2.52 2.73  mV

back to the tek, its max measurement works better.

V=2400 2500 2000 free running
	3.14 3.2 

V=2400 2600 2000 free running
	3.12 3.26 

V=2400 2500 2100 free running
	3.02 3.76 3.74 
coolant temp indicated 21.2

V=2400 2500 2000 q switched
	3.12 3.24 

V=2400 2500 2100 q switched
	3.74 3.76
ref only:	2.74 2.72 2.76 avg= 2.74 mV  61 uJ/cm^2 * cos(45) =43 uJ/cm^2


Hologram 208.1
frame ...-7792
charge
Charging!
>

>en

osc ready time= 1309  V= 2321
osc ready time= 1309  V= 2294
amp0 ready time= 2614  V= 2399
osc ready time= 1309  V= 2294
amp0 ready time= 2614  V= 2438
amp1 ready time= 3845  V= 2004
Ready!
remote Fire!
>
firecomplete
decision at 0x262b4e71  val= 0x8f80
min= 0x336e  max= 0x43ec  delta= 0x107e 536 usec
lamp 0  0x262b2e71  0x262c2eaa  len 8340 usec
lamp 1  0x262b43ec  0x262b94e9  len 2636 usec
lamp 2  0x262b42f5  0x262b6643  len 1149 usec
lamp 3  0x262b336e  0x262b5c93  len 1339 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x538c actual 0x262b538c 1207 usec
rflags 0x8f fflags 0x8f 


Hologram 208.2:

frames 8486
>en

osc ready time= 1320  V= 2294
osc ready time= 1320  V= 2289
amp0 ready time= 2618  V= 2360
osc ready time= 1320  V= 2305
amp0 ready time= 2618  V= 2399
amp1 ready time= 3783  V= 1956
Ready!
remote Fire!
>
firecomplete
decision at 0x15273014  val= 0x8f80
min= 0x151b  max= 0x2595  delta= 0x107a 536 usec
lamp 0  0x15271014  0x15281055  len 8341 usec
lamp 1  0x15272595  0x15277658  len 2628 usec
lamp 2  0x1527249b  0x152747ea  len 1149 usec
lamp 3  0x1527151b  0x15273e46  len 1340 usec
lamp 4  0x0  0x0  len 0 usec
Qswitch target 0x3535 actual 0x15273535 1208 usec
rflags 0x8f fflags 0x8f 


20201229

Warmup the coolant with a 50W aquarium heater:
Model predicts 5 minutes per degree, observing more like 30 min/degree

10:20	15.7C
10:22	16.0
10:24	16.0
10:26	16.1
10:28	16.2
10:30	16.3
10:32	16.5
10:34	16.6
10:36	16.7
10:38	16.9
10:40	17.0
10:42	17.2
10:44	17.3
10:46	17.4
10:48	17.4
10:50	17.6
10:52	17.7
10:54	17.8		(there was no 17.9, revealing DAC resolution)
10:56	18.0
10:58	18.0
11:00	18.1
11:02	18.2
11:04	18.3
11:06	18.4 
11:08
11:10	18.7
11:12	18.8
11:14	18.9
11:16	19.0
11:18	19.0
11:20	19.1
11:22	19.1
11:24	19.1	thermostat in heater tripped, increased its setting to "24"
11:26	19.1
11:28	19.1
11:30	19.2
11:32	19.4
11:34	19.4
11:36	19.5
11:38	19.6
11:40	19.7
11:42	19.7
11:44	19.9
11:46	20.0
11:48	20.0
11:50	20.1
11:52	20.1
11:54	20.3
11:56	20.4
11:58	20.4
12:00	20.5
12:02	20.6
12:04	20.7
12:06	20.7
12:08	20.7
12:10	20.8		There was no 20.9
12:12	21.0

Implemented aquarium heater SSR to the wannabe watlow.

2:04	19.7
2:06	19.7
2:10	19.7
2:15	19.9
2:20	20.1
2:25	20.2
2:30	20.4
2:35	20.7
2:40	20.7
2:45	20.9
2:46	21.0	(approx, relay clicked noticibly)
2:50	21.0

3:26	20.8
3:44	21.0

So the heat drifts down to 20.7, then back to 21, while cool drifts
up to 21.3, the back to 21.
