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  ATF eLog, Page 52 of 54  Not logged in ELOG logo
ID Date Author Type Category Subject
  120   Thu Apr 23 15:25:35 2009 DmassComputingDAQATF Screens/DAQ up and running.

I made screens for the lab from the atf.mdl file which is in the /cvs/cds/advLigo/src/epics/simLink/ directory

They live in /cvs/cds/caltech/medm/c2/atf/

C2ATF_MASTER has links to what is there.

We have two 8 in ---> 8 out filtered matrixed subsystems.

 

Pics to be included later.

Enjoy.

 

P.S. The DAQ is now writing at 16 kHz. If you want data at a different speed, there may be funniness that needs to happen with the /frames/full directory.

  119   Wed Apr 22 14:47:47 2009 DmassComputingDAQDAQ back up and running

This got the oms system back up and running. Data was going into the ADC, through the filters, and back out the DAC.

I got the ATF system up and running, but had to change one more thing.

in the /cvs/cds/caltech/target/fb/master file there is a line which tells you which .ini file to use (in /cvs/cds/caltech/chans/daq/) If this is not set correctly nothing will really work.

We can configure it to have more than one system run at the same time by giving them different dcuids, but until we want to do that, to change to a new system, after you configure your sys.ini file, you have to manually put it in the master file.

 

On to medm screens.

 

Quote:

This from Alex:

"Looks like we changed GM nodename from fb into fb0 in the code, so I had
to rename the node in /etc/gm/hostname.

It is up and running"

 

 

 

  118   Wed Apr 22 11:33:24 2009 DmassComputingDAQDAQ back up and running

This from Alex:

"Looks like we changed GM nodename from fb into fb0 in the code, so I had
to rename the node in /etc/gm/hostname.

It is up and running"

 

 

  117   Mon Apr 20 18:03:44 2009 dmassComputingDAQADC no longer working!

This all started when I did a cvs update. I have forwarded my concerns, trials, and tribulations to the russian.

 

Quote:

I was trying to get the ATF.mdl or OMS.mdl system back up and running, but neither could see fb0.

I telneted in with

>telnet fb0 8087

daqd> shutdown

to reboot fb0. It didn't fix the problem.

I also rebooted oms.

 

I discovered in the course of this that the oms.mdl file was overwritten with Alastair's model. I (saved and) replaced it with an old copy of the oms.mdl file from ws1, and did

make oms

make install-oms

make install-daq-oms

make install-screens-oms

startoms

but was no longer able to get a connection to fb0.

 

I then reinstalled Alastair's model, since it was the last thing I saw communicate with the fb succesfully. I am unsure what I am forgetting, possibly some command I need to run on oms after rebooting it. I was unable to get Alastair's model back up and talking to the framebuilder and I have thus left the DAQ slightly more broken than I found it.

Quote:

The output from the DAQ is now working, and the timing etc looks sensible, though still at 64khz.  I've only tested the four outputs I've setup in my model, but they all work when I use the output matrix to patch the signal to them.

 

 

 

  116   Sun Apr 19 16:08:03 2009 dmassLaserPSLThe chiller wants new filters

The chiller has been begging for new filters for a while. I don't know if we ever starting loggin the chiller data, but I expect the water to have the conductivity of lemon juice by now.

  115   Sun Apr 19 16:01:35 2009 dmassLaserPSLLaser On

I found the 35W on with the shutter closed @ 4pm Sunday. It was off as of 8pm friday, with the shutter closed. I checked the power out, and it was ~ 29W. The steering mirrors into the PMC are gone, and the DAQ system is down, so there will be no trending of power from the pickoff diode.

 

Since there seems to be nothing useful to do with the PSL without an unknown amount of troubleshooting, I am turning off the laser rather than leaving ir dumping onto the shutter, which is now nice and toasty.

I hope to have the DAQ and PMC Servo back soon.

 

  114   Fri Apr 17 20:05:59 2009 AidanLab InfrastructureGeneralAnother workbench and a filing cabinet

We're starting to accumulate a lot of loose data sheets and other paraphernalia. We should arrange to get a small filing cabinet down here. I'm sure Office Depot can serve us well on that one.

Also DMass and I think we should get a third IAC Industries workbench (the white ones with the Linux machines on them).

A.

 

 

  113   Fri Apr 17 20:04:17 2009 dmassComputingDAQADC no longer working!

I was trying to get the ATF.mdl or OMS.mdl system back up and running, but neither could see fb0.

I telneted in with

>telnet fb0 8087

daqd> shutdown

to reboot fb0. It didn't fix the problem.

I also rebooted oms.

 

I discovered in the course of this that the oms.mdl file was overwritten with Alastair's model. I (saved and) replaced it with an old copy of the oms.mdl file from ws1, and did

make oms

make install-oms

make install-daq-oms

make install-screens-oms

startoms

but was no longer able to get a connection to fb0.

 

I then reinstalled Alastair's model, since it was the last thing I saw communicate with the fb succesfully. I am unsure what I am forgetting, possibly some command I need to run on oms after rebooting it. I was unable to get Alastair's model back up and talking to the framebuilder and I have thus left the DAQ slightly more broken than I found it.

Quote:

The output from the DAQ is now working, and the timing etc looks sensible, though still at 64khz.  I've only tested the four outputs I've setup in my model, but they all work when I use the output matrix to patch the signal to them.

 

 

  112   Thu Apr 9 11:26:21 2009 alastairComputingDAQDAC now working

The output from the DAQ is now working, and the timing etc looks sensible, though still at 64khz.  I've only tested the four outputs I've setup in my model, but they all work when I use the output matrix to patch the signal to them.

  111   Thu Apr 9 10:02:24 2009 alastairLab InfrastructureGeneralAudio/mp3

We now have the right cable to connect audio equipment with a standard 2.5mm headphone jack (ipods etc) to the hi-fi.  Just set the stereo to 'game' and you're away.

  110   Thu Apr 9 09:52:54 2009 alastairLab InfrastructureDAQDAQ up and running

Thanks to the help of all the people I've been hassling about this, the DAQ system is up and running.

I'll try to put together more of an 'idiot's guide to the RCG' at some point in future to supplement the information in the manual.  In the mean time for those that are interested in what's running, we have a model that looks something like the attached images (OMS.mdl which can be found in /cvs/cds/advLigo/src/epics/simLink/)

The model has four inputs from the ADC (the ADC is the lower BNC connector unit in the rack, labelled 'BNC anti-alias chassis'), followed by input filters on each channel.  These then go to an input matrix.  The ouput also has a filter on each channel followed by an output matrix.  The signals then go to the DAC.

I've tested the input with a siggen, and we can see realtime stuff in dataviewer, and frequency domain in DTT.  This is all working now.  It's running at 64khz at the moment and we'll be altering this down to 32 at some point soon.

I have also built some filters in foton, and after some fiddling with the settings they're running at the correct frequency.

Next up I want to make sure I can get a sensible signal back out of the DAC and then do some noise measurements on the input and output of the system.

Attachment 1: model1.png
model1.png
Attachment 2: model2.png
model2.png
  109   Thu Mar 5 19:24:06 2009 ken mailandLaserGeneral35 watt table beam dump

3-4-2009

 

Crack Test of the si substrate to be used in the low scatter table beam dump.

Attached are a few pdf’ and Jpg’s showing various setups

 

Beam Dump Construction

 

The beam dump will be constructed of a mirror polished Stainless sq. cone {16 deg.} this cone will be baked, and a layer of oxidation will occur on its surface to absorb the beam energy at the rate of ~80% for each of 9 bounces.  The first bounce off an si substrate itself absorbing approx 98 percent ( the major portion ) of the energy.

 

The mount feet will be a small path, stainless material limiting the conductive flow to the table. The dump assembly can be mounted in a vertical or horizontal configuration at 3” and 4” heights from the table.

 

This assembly has been setup with a 40 watt fire rod to test the convection flow, with the fins vertical and horizontal showing that no point on the assembly exceeded 100 F.

 

SI Substrate Durability Test

 

The test is to determine if  the substrate will crack due to temperature differential in the substrate

local to the beam incidence.

 

The si mirror was set at brewster's angle ~73.4 deg for maximum absorption of the laser energy.

Rana and I set up the si substrate by simply clamping it to a stage, and adjusting, and orienting it to center the 1064 laser  beam.

 

Initially the laser output was 8.6 watts, the si substrate did not crack, the temperature rose to a steady 105 F after

about one minute.

 

Next after Peter King adjusted the laser internally a retest was made at 32 watts, this also did not crack the substrate and after about one minute the substrate temp rose to a steady 206 F. given the beam is smaller in diameter  than the actual beam, Rana’s opinion was it ‘passed’ the test and we should proceed with the design.

 

The beam dump when assembled will have a finned aluminum heat sink in contact with the substrate.

 

An additional test will be made to determine compatibility of the si interface material, re. thermal expansion of the

aluminum heat sink / bonding material / si substrate, in the end we can just pot it, and use the cone to secure the si in a machined recess in the heat sink body.

 

Attachment 1: Vertical_Test_Beam_Dump_Heat_Sink.jpg
Vertical_Test_Beam_Dump_Heat_Sink.jpg
Attachment 2: 32_watt_test.jpg
32_watt_test.jpg
Attachment 3: Beam_Dump_Assem_.jpg
Beam_Dump_Assem_.jpg
Attachment 4: Beam_Dump_Assem_.pdf
Beam_Dump_Assem_.pdf
  108   Wed Mar 4 15:20:14 2009 pkingLaserPSLlaser re-aligned
I fired up the laser this afternoon because Ken Mailand wanted to
test the silicon beam dump. The output power of the laser was pretty low,
around 8W or so. I re-aligned things a bit and now the output power is
around 32W. Further improvement involves opening up the amplifier I think.
This was all without adjusting any diode currents and wotnot. Just the
alignment.
  107   Fri Jan 23 16:48:29 2009 DmassLaserPSLChiller noise and DeI water
John Miller emailed me about the chiller once again whining. The water level was almost at the "min" line, and he filled it. This appears to not have been the culprit for the alarm. The screen on the chiller read "filters" and the noise stopped when I touched a button. The light in back which turned red when the water started to fail the deionized test is still red.

To my knowledge the following is the story

The new chiller wants Deionized water. It has brass fittings in it's plumbing, and by 40m lore, we do not mix brass fittings and deionized water - also Peter King said that it would be ok to use distilled water - I filled it with distilled water, and after a few weeks of stable operation (no noise or leaks) the red light on the back of the chiller went off (which I believe is triggered by the resistance of the water dropping too low). The high pitched whine of an alarm noise would periodically come on, and I would periodically turn it off. After this last time which I was notified of ~1 week ago by John Miller, the readout on the chiller said "filters" instead of "dei". I do not know how much attention we should pay to the purity of the water, and we may want to look into disabling the alarm if we continue using distilled water with the deionized water system.
  106   Wed Jan 14 18:14:23 2009 AidanThings to BuyFiberResidual things to buy for FS - extra photodiodes

Quote:

Quote:

A large fraction of the equipment is already in the lab from Masha's experiment earlier in the year. The following is required for the latest design of the experiment. In the interim we can probably use the Marconi to drive AOM1.


Specifics
---------
2x Half wave plates - QWPO-1064-05-2-R10
1x Quarter wave plate - QWPO-1064-05-4-R10
3x rotation stages - New Focus 9401


General
-------
Partially transmitting retro-reflector
AOM # 2
Mode-matching lenses (possibly - might have enough downstairs)
RF photodiodes - (10-MHz InGaAs Photoreceiver (Free Space input) Model 2053-FS?)
VCO + power amp for AOM#1 - center frequency probably 77.5MHz, ~2W to AOM
Crystal oscillator + power amp for AOM#2 - probably 80MHz, ~2W to AOM
Oscillator for demod - probably 5MHz, 17dBm

What else? hmm ...


Ordered the following:
2x Half wave plates - CVI - QWPO-1064-05-2-R10
1x Quarter wave plate - CVI - QWPO-1064-05-4-R10
3x rotation stages - New Focus - 9401
1x partially transmitting retro-reflector: CVI - PR1-1064-95-IF-1037 - 95% reflectance



Also ordered 2x Thorlabs - PDA10CS 17MHz InGaAs photodiodes
  105   Wed Jan 14 11:33:58 2009 AidanThings to BuyFiberResidual things to buy for FS - QWPs, HWPs, output coupler

Quote:

A large fraction of the equipment is already in the lab from Masha's experiment earlier in the year. The following is required for the latest design of the experiment. In the interim we can probably use the Marconi to drive AOM1.


Specifics
---------
2x Half wave plates - QWPO-1064-05-2-R10
1x Quarter wave plate - QWPO-1064-05-4-R10
3x rotation stages - New Focus 9401


General
-------
Partially transmitting retro-reflector
AOM # 2
Mode-matching lenses (possibly - might have enough downstairs)
RF photodiodes - (10-MHz InGaAs Photoreceiver (Free Space input) Model 2053-FS?)
VCO + power amp for AOM#1 - center frequency probably 77.5MHz, ~2W to AOM
Crystal oscillator + power amp for AOM#2 - probably 80MHz, ~2W to AOM
Oscillator for demod - probably 5MHz, 17dBm

What else? hmm ...


Ordered the following:
2x Half wave plates - CVI - QWPO-1064-05-2-R10
1x Quarter wave plate - CVI - QWPO-1064-05-4-R10
3x rotation stages - New Focus - 9401
1x partially transmitting retro-reflector: CVI - PR1-1064-95-IF-1037 - 95% reflectance
  104   Thu Jan 8 19:59:50 2009 AidanMiscGeneralEarthquake ...

Just felt the building shake. Didn't feel as a large as last year's quake.

Apparently a 5.0 in San Bernadino ...
  103   Tue Nov 25 17:30:32 2008 AidanLaserFiberPreliminary noise budgets for fibre stabilization

Here are some preliminary noise budgets for the FS experiment ... or rather, the setup shown in attached figure. Looks like the laser frequency noise dominates.
Not surprising given that the optical path length difference is ~150m.

The photodiode noise is not particularly high, although if we stabilize the frequency and intensity of the NPRO it might become a factor.

Anyway, the phase and frequency noise plots are attached. Will post references to the origin of the actual curves for the different noise sources soon.
Attachment 1: simulation_v1B.jpg
simulation_v1B.jpg
Attachment 2: phaseNoiseBudget-NPRO-PDA255.pdf
phaseNoiseBudget-NPRO-PDA255.pdf
Attachment 3: freqNoiseBudget-NPRO-PDA255.pdf
freqNoiseBudget-NPRO-PDA255.pdf
  102   Tue Nov 25 17:12:01 2008 AidanThings to BuyFiberResidual things to buy for FS

A large fraction of the equipment is already in the lab from Masha's experiment earlier in the year. The following is required for the latest design of the experiment. In the interim we can probably use the Marconi to drive AOM1.


Specifics
---------
2x Half wave plates - QWPO-1064-05-2-R10
1x Quarter wave plate - QWPO-1064-05-4-R10
3x rotation stages - New Focus 9401


General
-------
Partially transmitting retro-reflector
AOM # 2
Mode-matching lenses (possibly - might have enough downstairs)
RF photodiodes - (10-MHz InGaAs Photoreceiver (Free Space input) Model 2053-FS?)
VCO + power amp for AOM#1 - center frequency probably 77.5MHz, ~2W to AOM
Crystal oscillator + power amp for AOM#2 - probably 80MHz, ~2W to AOM
Oscillator for demod - probably 5MHz, 17dBm

What else? hmm ...
Attachment 1: adhikari_lab_v1C.jpg
adhikari_lab_v1C.jpg
  101   Sat Nov 8 21:38:17 2008 DmassLaserPSLChiller Noise

Quote:
The new chiller was making a noise (as reported to me by John).

It was emitting a continuous high pitched tone, and the display alternated between the set point temp, and "d1" or "di".
I hit enter twice, and it stopped. To be safe, I have turned the 35W off until I spend some time down here and make sure
that the chiller is ok. I have left the chiller on.


The chiller was making the noise again. Again it said di on the screen. The noise and warning went away when I pushed any button on the front panel. I think it's just a warning that the water no longer qualifies as DI, as the light on the back of the chiller was red (it's green when the resistance is high, red when low - either change the di cartridge or figure out how toe disable the noise. As we don't necessarily want to use DI water because of the metal plumbing, I am inclined to disable the warning noise if I can.
  100   Thu Oct 9 08:47:54 2008 AidanLaserFiberDismantled fiber stabilization setup


Packed up the current setup. Am going to rebuild with beam double passed through the fiber and an 80MHz AOM.
  99   Wed Oct 8 13:40:02 2008 DmassLaserPSLChiller Noise
The new chiller was making a noise (as reported to me by John).

It was emitting a continuous high pitched tone, and the display alternated between the set point temp, and "d1" or "di".
I hit enter twice, and it stopped. To be safe, I have turned the 35W off until I spend some time down here and make sure
that the chiller is ok. I have left the chiller on.
  98   Tue Sep 23 12:10:08 2008 AidanLaserFiberMaximized fiber coupler ROLL angle.

Set the input fiber coupler roll angle to 190 degrees on the graduated scale. Rotated the half wave plate after the output of the fiber to maximize the fringe magnitude output from the MZ.

Vpp max = 4.52V (peak-to-peak value of demodulated output of PD with residual 20Hz signal)
Vpp min = 4.22V

Fringe magnitude fluctuation = 7% of maximum fringe magnitude.

(All this was running open loop in the fiber stabilization, by the way)
  97   Tue Sep 23 10:15:15 2008 AidanLaserFiberFringe magnitude fluctuation investigation - why isn' the maximum 45 degrees from the minimum?

Quote:

The attached photo shows the fiber coupler in question and the ROLL angle adjustment and graduations (set to 120 degrees)

Using Masha's fiber stabilization setup, I looked at the interference fringe magnitude on transmission through the fiber. The frequency difference between the two arms in the MZ interferometer was (200MHz + 20Hz = 200.000020MHz). I demodulated the output by exactly 200MHz leaving a 20Hz signal on the output. I observed this output on an oscilloscope and monitored the fringe magnitude over time. In the past, the magnitude has been observed to drift (Eric G thinks this is most likely due to the input into the polarization maintaining fiber not being injected with the correct polarization). Over a period of 2-3 minutes I recorded the maximum and minimum fringe magnitudes (the maximum and minimum peak-to-peak values). I did this for several of ROLL rotation angles for the input fiber coupler (FC1). I only did a quick job of optimizing the output of the fiber when it was rotated to a new position, but I did secure it into that position once it was optimized.

Here are the results:
Fringe Size (Vpp)
ROLL ANGLE | MAXIMUM (V) | MINIMUM (V)
--------------------------------------------
120 deg | 3.27 | 0.04
139 deg | 4.00 | 1.60
150 deg | 4.74 | 2.64
165 deg | 4.94 | 3.62
180 deg | 4.42 | 3.88
195 deg | 3.80 | 3.48
210 deg | 3.36 | 2.54
225 deg | 2.53 | 1.47
240 deg | 1.84 | 0.68
255 deg | 1.46 | 0.15
---------------------------------------------

We can define the relative fluctuation in the fringe visibility/magnitude as the difference between the maximum and minimum divided by the maximum fringe size. The results are shown in the attached plot. It's obvious that the optimum rotation angle to be at is at arodun 190 degrees.


The reason that the output polarization wanders is as follows: the fiber is birefringent and will, in general, convert linearly polarized light into elliptically polarized light unless the input is aligned with the fast axis of the fiber. So, in this respect, it functions exactly like every other birefringent material. The fiber complicates matters because small changes in its length (e.g. due to temperature fluctuations) will vary the phase delay between the fast and slow axes and cause the ellipticity of the output light to fluctuate ... again, assuming that the light is not aligned with the fast axis.

So if the input field is mostly aligned with the fast axis (e.g. in the 175 - 205 degree range) then the output polarization fluctuates between being linearly polarized and slightly elliptically polarized. If it is far from being aligned then the polarization of the output is expected to fluctuate by a large amount.

Which leaves a problem ... shouldn't the maximum amount of polarization fluctuation occur at 45 degrees from the fast axis? After all, if the input field is 100% aligned to the slow axis then one would naively expect that the polarization should be insensitive to fluctuations in length. It might be time to get a PBS into the system to look at the output from the fiber.
  96   Mon Sep 22 20:20:25 2008 AidanLaserFiberFringe magnitude fluctuation investigation

The attached photo shows the fiber coupler in question and the ROLL angle adjustment and graduations (set to 120 degrees)

Using Masha's fiber stabilization setup, I looked at the interference fringe magnitude on transmission through the fiber. The frequency difference between the two arms in the MZ interferometer was (200MHz + 20Hz = 200.000020MHz). I demodulated the output by exactly 200MHz leaving a 20Hz signal on the output. I observed this output on an oscilloscope and monitored the fringe magnitude over time. In the past, the magnitude has been observed to drift (Eric G thinks this is most likely due to the input into the polarization maintaining fiber not being injected with the correct polarization). Over a period of 2-3 minutes I recorded the maximum and minimum fringe magnitudes (the maximum and minimum peak-to-peak values). I did this for several of ROLL rotation angles for the input fiber coupler (FC1). I only did a quick job of optimizing the output of the fiber when it was rotated to a new position, but I did secure it into that position once it was optimized.

Here are the results:
Fringe Size (Vpp)
ROLL ANGLE | MAXIMUM (V) | MINIMUM (V)
--------------------------------------------
120 deg | 3.27 | 0.04
139 deg | 4.00 | 1.60
150 deg | 4.74 | 2.64
165 deg | 4.94 | 3.62
180 deg | 4.42 | 3.88
195 deg | 3.80 | 3.48
210 deg | 3.36 | 2.54
225 deg | 2.53 | 1.47
240 deg | 1.84 | 0.68
255 deg | 1.46 | 0.15
---------------------------------------------

We can define the relative fluctuation in the fringe visibility/magnitude as the difference between the maximum and minimum divided by the maximum fringe size. The results are shown in the attached plot. It's obvious that the optimum rotation angle to be at is at arodun 190 degrees.
Attachment 1: fiber_coupler_rotation_angle_output_fluctuation.jpg
fiber_coupler_rotation_angle_output_fluctuation.jpg
Attachment 2: 00003.jpg
00003.jpg
  95   Mon Sep 22 18:03:34 2008 DmassComputingDAQDAQ IS BACK - as is the 35W
The Chiller appears to not be leaking.
There are no squeaks coming from under the table.
The 35W is on.
The DAQ is recording again (fix detailed below)
The 35W is being trended at a pickoff post-MOPA
The 2W NPRO will be trended when I get my hands on the PD schematic from the Germans. PK emailed them


I talked to Alex, and it seems the problem was in
controls@oms > /frames/full/dataxx

I had changed the filesize apparently (by changing the sample rate), and the software doesn't correct for that in the number of files it keeps.

I had to edit /cvs/cds/caltech/target/fb/daqdrc

I deleted all the files in /frames/full, then decreased the sample rate in
/cvs/cds/caltech/chans/daq/C2OMS.ini to 16 kHz for the channels I am interested in.

Then I upped the number of dataxx files to 120 from 60 to correct for the factor of 2 it was off by before, and the factor of four division in sample rate I gave it in daqdrc.

Then I tried to make everything again in advLigo by running:
* make uninstall-daq-oms
* make clean-oms oms install-oms
* make install-daq-oms
* make install-screens-oms
* startoms


I looked at the log files for the fb in /cvs/cds/caltech/target/fb/logs/* and found errors about the dataxx files (which I had deleted) not existing, so I replaced them by hand with the following in a bash file (filename.sh):
#!/bin/bash
for i in `seq 0 119`; do
mkdir "data$i"
done

and running it with >bash filename.sh in the /frames/full directory.

I then rebuilt everything, restarted the fb by telneting in
* telnet fb0 8087
daqd>shutdown


and reset the daq in the oms medm screens via the reset button. After all this the data was writing again.
  94   Sun Sep 21 15:45:21 2008 DmassLaserPSLChiller on. 35W on.

Quote:
Peter got word back from Christian and told me how to modify the adapter he made (schematic to be posted later when he emails it to me). The errors disappeared and then we modified the chiller settings to LZH specifications except for

r.start (we had to set it to off rather than on to get the chiller to turn on).

The chiller has shown no signs of leaking and it has been on for ~24 hours now.
The 35W is back on. There is something wrong with the DAQ again, and I can not get it to write. I do not think anyone has modified anything at our end since we last had it working.

I am turning the laser off over the weekend since we are not trending. I am leaving the chiller on with a bucket underneath the new fittings incase it develops a drip.


There appears to have been a small (a few cc's over a couple days) leak coming from the circled fitting. I tightened the offending wireclamp significantly (~3.5 turns) without worrying about damaging the hose as we are using the incredibly thick walled clear plastic hose. I also noticed some wetness coming from the joint indicated in the picture by the green arrow. I removed it, replaced the teflon tape, and re-tightened it.

I also used some cable ties to support the plumbing so it wouldn't put all the weight on my plumbing joint.

I left the bucket underneath, and will be checking the chiller daily to see if the leak is still there.

There was no apparent wetness after several hours.
Attachment 1: Chiller_Back.png
Chiller_Back.png
  93   Fri Sep 19 13:18:00 2008 DmassLaserPSLChiller on. 35W on.
Peter got word back from Christian and told me how to modify the adapter he made (schematic to be posted later when he emails it to me). The errors disappeared and then we modified the chiller settings to LZH specifications except for

r.start (we had to set it to off rather than on to get the chiller to turn on).

The chiller has shown no signs of leaking and it has been on for ~24 hours now.
The 35W is back on. There is something wrong with the DAQ again, and I can not get it to write. I do not think anyone has modified anything at our end since we last had it working.

I am turning the laser off over the weekend since we are not trending. I am leaving the chiller on with a bucket underneath the new fittings incase it develops a drip.
  92   Tue Sep 16 22:55:30 2008 DmassLaserPSLConnectors needed
Peter King and I hooked up the chiller to itself and ran it looking for "gunk" in the system. We satisfied ourselves that there was none, and I connected it to the laser and control box after a minor undertaking to get the adapters we need to hook the new chiller up to the old hardware. I ended up only adding one 3 inch piece of tubing with barbed 3/8 inch connections + wire clamps to hold it on.

We turned on the system and there are no obvious leaks. I replaced the DI water with distilled, since there are loads of brass fittings in the new chiller (PK agreed with this logic). There was a small light on the back which goes red if the conductivity of your water is too high. It did.

There is also a DI filter to reduce the conductivity of your water. It seems to work, as our warning light turned to green after about 10 minutes of running.

Peter gave me a dongle (15 pin dsub to 15 pin dsub) to adapt the the new chiller to the old control box. He made this via Christian's instructions. We were unable to get the diode box to turn the diodes on, and were presented with the following errors:
Flow control error - system off (when nothing was connected) and:
Chiller overtemp error - system off (when we had the adapter connected),

We tried using the old breakout "cheater" board to short the various pins to each other, and were unable to bypass the diode control box's unhappiness. PK is contacting Christian about this.

The chiller seems ok - but it will not play nice with the control box, so the 35W is still off at this point


Quote:
I got the replacement chiller (a Neslab Thermoflex1400) from 046 W. Bridge. I unpacked it and moved it by the PSL optics table in 058 W. Bridge. Peter King called LZH and is going to make the connector adaptation we need for the new Chiller unit.

I also siphoned the water out of the old chiller to see what plumbing fittings we may need in moving to the new unit. It was delicious.

I will not be firing the 35W laser back up until I have had the all clear from Rana after I make the chiller swap.

Update: The plastic pipe fittings from the old unit are 3/8" BSPT tapered threads. The new chiller takes 1/2" normal threads. The 1/2" male to 3/8" female adapter I got from Home Depot are relatively useless as a long term solution and would probably damage the BSPT tapered threading. We can either get some cheap barbed style T-splitter and make stuff with hoses or order some BSPT adapters. I am inclined to order both and sort it out later as they are relatively cheap. This appears to be the only remaining hitch in the chiller swap.

Update2: I have ordered more new fittings from McMastercarr. I will make a summary post of all the wonderful things learned in this process.



Quote:

Quote:
I am trying to chase down the source of the long time scale sharp fluctiations in intensity. I need to start reading out the diagnostic PD from inside the MOPA head unit to see if the power fluctuations are coming before or after the amplification (e.g. NPRO or MOPA problems).

I need the following connectors from Wilson house:



Update: I talked to Peter King about swapping the chiller which appears to be the cause of the fluctuations in the power. Our current model, as the prototype, is an earlier generation from what he has, which is current with what is on site. He needs to talk to LZH to figure out if there is any additional hardware we need for the swap.

He also said that the sites used Deionized water for cooling, but said that filtered water would probably be fine. I did not get a good definition on what "filtered" consisted of. If we did move to DeI, then we might need some new plumbing. I told Peter that if things needed to be purchased we would find the money if it meant pulling copper piping from homes in Inglewood.

As we think this is the problem, I may wait on setting up data logging from the diagnostic (pre-mopa) photodiode in the head unit.
  91   Tue Sep 9 16:36:01 2008 DmassLaserPSLConnectors needed
I got the replacement chiller (a Neslab Thermoflex1400) from 046 W. Bridge. I unpacked it and moved it by the PSL optics table in 058 W. Bridge. Peter King called LZH and is going to make the connector adaptation we need for the new Chiller unit.

I also siphoned the water out of the old chiller to see what plumbing fittings we may need in moving to the new unit. It was delicious.

I will not be firing the 35W laser back up until I have had the all clear from Rana after I make the chiller swap.

Update: The plastic pipe fittings from the old unit are 3/8" BSPT tapered threads. The new chiller takes 1/2" normal threads. The 1/2" male to 3/8" female adapter I got from Home Depot are relatively useless as a long term solution and would probably damage the BSPT tapered threading. We can either get some cheap barbed style T-splitter and make stuff with hoses or order some BSPT adapters. I am inclined to order both and sort it out later as they are relatively cheap. This appears to be the only remaining hitch in the chiller swap.

Update2: I have ordered more new fittings from McMastercarr. I will make a summary post of all the wonderful things learned in this process.



Quote:

Quote:
I am trying to chase down the source of the long time scale sharp fluctiations in intensity. I need to start reading out the diagnostic PD from inside the MOPA head unit to see if the power fluctuations are coming before or after the amplification (e.g. NPRO or MOPA problems).

I need the following connectors from Wilson house:



Update: I talked to Peter King about swapping the chiller which appears to be the cause of the fluctuations in the power. Our current model, as the prototype, is an earlier generation from what he has, which is current with what is on site. He needs to talk to LZH to figure out if there is any additional hardware we need for the swap.

He also said that the sites used Deionized water for cooling, but said that filtered water would probably be fine. I did not get a good definition on what "filtered" consisted of. If we did move to DeI, then we might need some new plumbing. I told Peter that if things needed to be purchased we would find the money if it meant pulling copper piping from homes in Inglewood.

As we think this is the problem, I may wait on setting up data logging from the diagnostic (pre-mopa) photodiode in the head unit.
  90   Tue Sep 9 15:49:22 2008 DmassLab InfrastructureHVACHEPA Filters
I had turned off the east HEPA filter with Masha for a noise measurement, and I forgot to turn it back on until today. Also, it looks like someone had unplugged the west HEPA filter and not plugged it back in. The latter I noticed while changing the power cabling, so it's possible that the west HEPA was running the whole time and I only noticed that I had just unplugged it...but I think this was a long term situation.

Also, the particle counter was reclaimed by the 40m during the vent after the earthquake, so we haven't had one on the table for some time. I had not been running the laser that much during the time when both filters may have been off, but it is worth noting in case there is unexplained dirtiness noticed in the future.
  89   Fri Sep 5 03:24:37 2008 DmassLaserPSLConnectors needed

Quote:
I am trying to chase down the source of the long time scale sharp fluctiations in intensity. I need to start reading out the diagnostic PD from inside the MOPA head unit to see if the power fluctuations are coming before or after the amplification (e.g. NPRO or MOPA problems).

I need the following connectors from Wilson house:



Update: I talked to Peter King about swapping the chiller which appears to be the cause of the fluctuations in the power. Our current model, as the prototype, is an earlier generation from what he has, which is current with what is on site. He needs to talk to LZH to figure out if there is any additional hardware we need for the swap.

He also said that the sites used Deionized water for cooling, but said that filtered water would probably be fine. I did not get a good definition on what "filtered" consisted of. If we did move to DeI, then we might need some new plumbing. I told Peter that if things needed to be purchased we would find the money if it meant pulling copper piping from homes in Inglewood.

As we think this is the problem, I may wait on setting up data logging from the diagnostic (pre-mopa) photodiode in the head unit.
  88   Wed Sep 3 18:22:20 2008 AidanLaserFiberCalibrated noise spectra ... does not agree with previous measurements

Quote:
I recorded the closed loop, open loop and electronics noise in the current fiber stabilization system (single-pass through fiber, AOM after fiber). The NPRO current level was set to 1.500A. The calibrations were applied to convert from counts to radians (see here for details). The results are plotted in the attached diagram (available in JPG and EPS flavours for your viewing pleasure).

I'm concerned that the magnitude of these results are not consistent with the noise measurements made previously using the spectrum analyzer(?) ... (see here). It's probably something straightforward that I'm missing.


Apparently the previous measurements were with a different fiber.
  87   Wed Sep 3 16:43:56 2008 Aidan, BramLaserFiberFringe visibility fluctuation ... Bram's suggestions

Quote:

I tried to calibrate the fiber phase noise measurements in DTT by determining the fringe visibility (peak-to-peak size) in counts (to determine radians per count). I shifted the carrier on the VCO by 100Hz to 200.0001MHz and left the other signal generator (LO for both mixers) at exactly 200MHz. The demodulated signals from the PDs then looked like nice 100Hz sine waves. It was only then that I noticed that the amplitude of these sine waves was varying by 50% over a timescale of 20 seconds to a number of minutes.

NPRO level: 1.500A

I plotted 20 minutes worth of Max-Min data from the 2 PDs in DataViewer (see attached pdf) - there was 100Hz frequency difference between the signal generators for all but the first four minutes or so of this plot. In principle this plot shows the fringe visibility in counts and can be used for calibration purposes. As you can see, though, the pk-pk value is fluctuating with time. Presumably, as nothing has been altered on the table over the last week, the fringe visibility has been fluctuating for all previous noise measurements. Therefore only a rough calibration is possible. So here it is ...

C2: OMS-SUS_TOP1_INI_65536: pi radians: [-2750, -700] counts -> ~1500 urad/count
C2: OMS-SUS_TOP2_INI_65536: pi radians: [-3600, 4000] counts -> ~410 urad/count

Eric G happened to come in shortly after I had discovered this. He suggested that the mode-matching between the two beams may not be good enough. I will look into this.



Just got this email from Bram ... will check the state of the polarization coming out of the fiber and see if it fluctuates in the sync with the fringe visibility.


Quote:

Hi Aidan,

I just saw your elog entries about the fluctuations of the fringe visibility. If you are using PM fiber, make sure you inject into the one of the axis of the fiber, otherwise there will be power fluctuations after the fiber. If I recall on the photos you made earlier, you don't have any polarising optics in the layout.

I guess some waveplates (and maybe even a PBS) will do the trick before the fiber to align the polarisation with one of the fiber axis, and after the fiber to align the polarisation with the LO.

If I recall if you within 6 degrees of the fiber axis you can get ~ -20dB fluctuations, if going within ~2 degrees then this will drop to -30dB (got this out of an article form the Ozoptics website).

Hope this helps,

Cheers,
Bram

PS. We have exactly the same problem....:)

  86   Wed Sep 3 13:35:56 2008 AidanLaserFiberCalibrated noise spectra ... does not agree with previous measurements
I recorded the closed loop, open loop and electronics noise in the current fiber stabilization system (single-pass through fiber, AOM after fiber). The NPRO current level was set to 1.500A. The calibrations were applied to convert from counts to radians (see here for details). The results are plotted in the attached diagram (available in JPG and EPS flavours for your viewing pleasure).

I'm concerned that the magnitude of these results are not consistent with the noise measurements made previously using the spectrum analyzer(?) ... (see here). It's probably something straightforward that I'm missing.
Attachment 1: noise_calibrated_080902.jpg
noise_calibrated_080902.jpg
Attachment 2: noise_calibrated_080902.eps
noise_calibrated_080902.eps
  85   Tue Sep 2 23:09:38 2008 AidanLaserFiberAttempted calibration of fiber noise. NPRO current = 1.903A

Quote:

I tried to calibrate the fiber phase noise measurements in DTT by determining the fringe visibility (peak-to-peak size) in counts (to determine radians per count). I shifted the carrier on the VCO by 100Hz to 200.0001MHz and left the other signal generator (LO for both mixers) at exactly 200MHz. The demodulated signals from the PDs then looked like nice 100Hz sine waves. It was only then that I noticed that the amplitude of these sine waves was varying by 50% over a timescale of 20 seconds to a number of minutes.

NPRO level: 1.500A

I plotted 20 minutes worth of Max-Min data from the 2 PDs in DataViewer (see attached pdf) - there was 100Hz frequency difference between the signal generators for all but the first four minutes or so of this plot. In principle this plot shows the fringe visibility in counts and can be used for calibration purposes. As you can see, though, the pk-pk value is fluctuating with time. Presumably, as nothing has been altered on the table over the last week, the fringe visibility has been fluctuating for all previous noise measurements. Therefore only a rough calibration is possible. So here it is ...

C2: OMS-SUS_TOP1_INI_65536: pi radians: [-2750, -700] counts -> ~1500 urad/count
C2: OMS-SUS_TOP2_INI_65536: pi radians: [-3600, 4000] counts -> ~410 urad/count

Eric G happened to come in shortly after I had discovered this. He suggested that the mode-matching between the two beams may not be good enough. I will look into this.


I repeated this measurement with the NPRO drive current set to 1.903A as per noise measurements made by Masha before she left. The same behaviour in the fringe visibility was seen. Additionally I noticed that the SR560 for channel 2 was periodically overloading. I didn't alter the gain on this amplifier because this was the state that the system was in for Masha's measurements. Attached is the max-min counts in the presence of a 100Hz frequency difference between the VCO and LO carrier frequencies. The following estimates for the radians/count calibrations are quite rough.


CH2: OMS-SUS_TOP1_IN1_65536: pi radians: [-4500, 1000] counts -> 570 urad/count
CH2: OMS-SUS_TOP2_IN1_65536: pi radians: [-6500, 6500] counts -> 240 urad/count
Attachment 1: peak_peak_calibration_1903mA.eps
peak_peak_calibration_1903mA.eps
  84   Tue Sep 2 22:48:47 2008 DmassLaserPSLConnectors needed
I am trying to chase down the source of the long time scale sharp fluctiations in intensity. I need to start reading out the diagnostic PD from inside the MOPA head unit to see if the power fluctuations are coming before or after the amplification (e.g. NPRO or MOPA problems).

I need the following connectors from Wilson house:
Attachment 1: connectors.png
connectors.png
  83   Tue Sep 2 15:06:42 2008 AidanLaserFiberAttempted calibration of fiber noise ... issues!

I tried to calibrate the fiber phase noise measurements in DTT by determining the fringe visibility (peak-to-peak size) in counts (to determine radians per count). I shifted the carrier on the VCO by 100Hz to 200.0001MHz and left the other signal generator (LO for both mixers) at exactly 200MHz. The demodulated signals from the PDs then looked like nice 100Hz sine waves. It was only then that I noticed that the amplitude of these sine waves was varying by 50% over a timescale of 20 seconds to a number of minutes.

NPRO level: 1.500A

I plotted 20 minutes worth of Max-Min data from the 2 PDs in DataViewer (see attached pdf) - there was 100Hz frequency difference between the signal generators for all but the first four minutes or so of this plot. In principle this plot shows the fringe visibility in counts and can be used for calibration purposes. As you can see, though, the pk-pk value is fluctuating with time. Presumably, as nothing has been altered on the table over the last week, the fringe visibility has been fluctuating for all previous noise measurements. Therefore only a rough calibration is possible. So here it is ...

C2: OMS-SUS_TOP1_INI_65536: pi radians: [-2750, -700] counts -> ~1500 urad/count
C2: OMS-SUS_TOP2_INI_65536: pi radians: [-3600, 4000] counts -> ~410 urad/count

Eric G happened to come in shortly after I had discovered this. He suggested that the mode-matching between the two beams may not be good enough. I will look into this.
Attachment 1: peak_peak_calibration.pdf
peak_peak_calibration.pdf
  82   Tue Sep 2 11:01:00 2008 AidanElectronicsFiberFiber stabilization loop diagram
Attached is a diagram of the current version of the stabilization loop. The beam (red) into the AOM is the output from the fiber and the other red line represents the reference beam.
  81   Wed Aug 20 23:19:39 2008 DmassLaserDoublingPreliminary Doubling MZ Setup
A prelim expermintal setup for measuring the phase/freq noise of 532 nm light generated by PPKTP crystals relative to the 1064 nm seed light from the YAG laser.

The mirrors in the Mach-Zehnder will all be dichroically reflective. The pink mirrors on the output will be reflective in one wavelength, and transmissive in the other.

I may need to add some sort of absorption/reflection before the PPKTP crystals for the green light if it is emitted in both directions by the SHG process.

I should be able to look at the difference between the MZ output in 1064 and 532 to isolate the more interesting sources of noise (phase/frequency) from the acoustic noise.
Attachment 1: MachZenderPPKTP.PNG
MachZenderPPKTP.PNG
  80   Mon Aug 18 23:46:42 2008 DmassComputingDAQMore on the DAQ
It appeared today that the DAQ channels wouldnt record. Only one would write no matter how I edited the .ini file.

I rebuilt everything, and the channels had the _32xxx suffix instead of the _DAQ suffix, and proceeded to write to the DAQ, allowing Masha to continue to slave away.
  79   Fri Aug 15 15:59:07 2008 DmassComputingDAQDAC DAQ and ADC working
The problem was the timing. I changed what the simulink .mdl file wanted for a clock signal to what it was actally getting (64 kHz), and everything was magically ok.

It appears that the ADC can function at 32kHz with a 64kHz clock signal, but the DAC apparently can not.

Several PC board were removed and/or inspected before I realized that I should change this.
  78   Fri Aug 15 02:17:46 2008 DmassElectronicsGeneralno DAC output voltage when running OMS didgital system

Quote:
I tried to use the OMS digital system for a measurement, but I couldn't get the DAC output to work.

Symptoms:
- All EPICS buttons work, and digital read-backs make sense
- ADC works just fine
- DAC output voltage is zero, no matter what the filter module output says
- Watchdog is enabled (green)


I talked to Alex, he suggested it was a hardware problem. I then talked to Rich, who in turn suggested it was a software problem.

As far as we know, nothing has changed about the hardware configuration since it was working earlier this year.
That said, I tried several things to troubleshoot.

I borrowed the SCSI breakout board from Wilson house, and plugged it into the anti aliasing box.
I was able to drive the AA box and see the signal make it through.

I turned everything in the crate off.

Then I moved the LASTI timing box below the blue PCIX box so I could open the latter up.
I grounded myself with a static strap, and the breakout board with a wire to the chassis of the PCIX box.

I then put the breakout board directly at the output of the DAC inside the blue PCIX box. I was
careful to elevate it via rubber feet and not let the bottom touch anything.

I then turned everything back on and restarted the fe machine with:
*ssh oms
*startoms
and from ws1:
*telnet fb0 8087
*shutdown
:noteworthy errors from the above follow at the end of this entry:
This got everything up and as working as it was before I started tinkering. I sent a booming signal through the ADC into the
system and (supposedly) to the DAC at channel 1. I was not able to see any difference on the scope when looking at channel one of the DAC.

I could not do a similar test to the ADC for comparison because it was not a SCSI connector inside the box.
I was able to see my signal when I connected the breakout board to the ADC input outside the PCIX box.

I then turned everything off, undid my troubleshooting rig, and closed the PCIX box up. I restarted again, and appear
to have all former functionality, so it seems I broke nothing new in my exploration.

I now suspect that it has something to do with the following errors in the code:

when I do a startoms after ssh'ing in, I get (among other things):
epicsThreadOnce0sd epicsMutexLock failed

Also, in the log file located at /cvs/cds/caltech/target/c2oms/log.txt the last three lines read:

Triggered the ADC
Net fail to fb0
DIAG RESET

Both of these things sound ominous, so I shall point them out to either Rob or the Russian, whoever I can get my hands on first.
  77   Mon Aug 11 15:32:00 2008 Stefan BallmerElectronicsGeneralno DAC output voltage when running OMS didgital system
I tried to use the OMS digital system for a measurement, but I couldn't get the DAC output to work.

Symptoms:
- All EPICS buttons work, and digital read-backs make sense
- ADC works just fine
- DAC output voltage is zero, no matter what the filter module output says
- Watchdog is enabled (green)
  76   Mon Aug 11 14:15:57 2008 DmassComputingCDSATF system

Quote:
I made a preliminary generic model in simulink. This is stored on ws1 as /users/dmass/atf.mdl

I copied this to /cvs/cds/advLigo/src/epics/simLink/atf.mdl on machine oms.

I changed directories to /cvs/cds/advLigo and ran the make commands. Everything seemed to run, but there was no data coming through (fb0 seemed to not start up). I then found this post in the SUS_Lab elog by Sam. I ran the commands it said to run because of the 'broken nature of the DAQ code,' and everything seemed to work.

In the end, I ran the following sequence of commands on oms in the /cvs/cds/advLigo directory, and was able to get the frontend up and receiving data. The daq, however, is still not writing anything.

*make clean-atf atf install-atf
*rm /cvs/cds/caltech/chans/daq/C2ATF.ini (this step is needed because the DAQ install code isn't quite right at the time of this writing
*make install-daq-atf
*make install-screens-atf


I talked to Alex, and he told me something about "your frames file is full, let me empty it and call you back," and he did so.

I did a reinstall of the daq
make unistall-daq-oms
and
make install-daq-oms

then I edited the .ini files with the channel names I wanted information about in

/cvs/cds/caltech/chans/daq/
C2OMS.ini is the file with the information I want in it.
oms.ini is the file which daqconfig interfaces with.

I edited the files via the daqconfig, and then overwrote the C2OMS.ini file with it, then data seemed to be recording and I could access it via dataviewer.

One concern/piece of information:
Apparently at some point they decided to change the convention on file suffixes for channel names. C2OMS.ini has a *_32768 tacked onto the end of
the channel name upon generation by the make scripts, whereas the oms.ini file has a *_DAQ in its place. This seemed to be the cause for some
of the noncooperation between the various sytems. Daqconfig likes the *_DAQ suffix, and this seems to jive with the data now writing, so we shall
go with that.
  75   Tue Aug 5 15:23:38 2008 DmassComputingCDSATF system

Quote:
I made a preliminary generic model in simulink. This is stored on ws1 as /users/dmass/atf.mdl

I copied this to /cvs/cds/advLigo/src/epics/simLink/atf.mdl on machine oms.

I changed directories to /cvs/cds/advLigo and ran the make commands. Everything seemed to run, but there was no data coming through (fb0 seemed to not start up). I then found this post in the SUS_Lab elog by Sam. I ran the commands it said to run because of the 'broken nature of the DAQ code,' and everything seemed to work.

In the end, I ran the following sequence of commands on oms in the /cvs/cds/advLigo directory, and was able to get the frontend up and receiving data. The daq, however, is still not writing anything.

*make clean-atf atf install-atf
*rm /cvs/cds/caltech/chans/daq/C2ATF.ini (this step is needed because the DAQ install code isn't quite right at the time of this writing
*make install-daq-atf
*make install-screens-atf


The rm /cvs... command should be replaced by make uninstall-daq-atf. It does the removal and slightly more.
  74   Fri Aug 1 15:06:11 2008 DmassComputingCDSATF system
I made a preliminary generic model in simulink. This is stored on ws1 as /users/dmass/atf.mdl

I copied this to /cvs/cds/advLigo/src/epics/simLink/atf.mdl on machine oms.

I changed directories to /cvs/cds/advLigo and ran the make commands. Everything seemed to run, but there was no data coming through (fb0 seemed to not start up). I then found this post in the SUS_Lab elog by Sam. I ran the commands it said to run because of the 'broken nature of the DAQ code,' and everything seemed to work.

In the end, I ran the following sequence of commands on oms in the /cvs/cds/advLigo directory, and was able to get the frontend up and receiving data. The daq, however, is still not writing anything.

*make clean-atf atf install-atf
*rm /cvs/cds/caltech/chans/daq/C2ATF.ini (this step is needed because the DAQ install code isn't quite right at the time of this writing
*make install-daq-atf
*make install-screens-atf
  73   Fri Aug 1 14:52:27 2008 DmassComputingDAQDaq not recording

Quote:
There is still something wonky with the DAQ. Nothing appears to be writing at the moment, as I can only get 8 seconds of data from the playback in dataviewer. I may table this until I am trying to get the new system up and running.


I abducted Rob from the 40m to look at this, and he thinks it has something to do with the fact that awgtpman (the test point manager) will not run. He beat at it with his kung-fu, but the computer would not yield. Ws1 does not yet know fear, but it shall soon learn.
  72   Tue Jul 29 00:58:36 2008 MashaLaserFiberfirst fiber noise measurement
I'm attaching the fiber noise measurement from one mach zehnder channel
along with some noise sources. The total rms phase noise comes out to about
0.075 radians, which translates to a frequency noise of 20Hz rms.

I will take spectra at lower frequencies once the DAQ is back up so I don't
have to wait an hour for the spectrum analyzer.
Attachment 1: MZnoise_sources0727.png
MZnoise_sources0727.png
  71   Tue Jul 29 00:47:37 2008 MashaLaserFibermach zehnder setup
As per dmass's prodding, I am putting up some pictures of what I'm doing.

Currently there is a working Mach Zehnder, but it needs to be improved.
Right now the fluctuations due to phase are about 15% of the total DC voltage,
where they were over 50% back at the 40m.On the list are more stable mounts
and better mode matching for fiber input and output with the laser. Also, we
will be putting in an AOM in the fiber arm.
Attachment 1: setup1.JPG
setup1.JPG
Attachment 2: setup3.JPG
setup3.JPG
Attachment 3: setup4.JPG
setup4.JPG
ELOG V3.1.3-