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  40m Log, Page 123 of 344  Not logged in ELOG logo
ID Date Authorup Type Category Subject
  17023   Wed Jul 20 15:58:52 2022 KojiSummaryGeneralJenne laser kaput!

For troubleshooting, the proper laser driver (found beneath the AG network analyzer) was connected.
The current ~1mA was provided and the driver detected the "open circuit", which means the laser diode was busted.


The laser diode in the parts list is: "GTRAN GaAs Strained QW Laser Diode, Part # LD-1060".

  17027   Fri Jul 22 17:43:19 2022 KojiUpdateGeneralObtained a functional CRT

[Koji Paco]

Koji went to Downs and found a CRT labeled "for 40m Rana?". So I decided to salvage it to the 40m after getting approval from Rich/Todd.

Paco and I tried this unit with the control room CCD signal and it just worked fine. So we can use this as a spare for any purpose in the lab.

Attachment 1: PXL_20220723_003631871.jpg
  17038   Tue Jul 26 21:16:41 2022 KojiUpdateComputer Scripts / ProgramsVector fitting

I think the fit fails as the measurement quality is not good enough.


  17043   Thu Jul 28 15:11:59 2022 KojiUpdateCDSToo huge script_archive

As a result of the following work, the file volume of /cvs/cds was reduced from 3.2TB to 2.2TB, and /opt/rtcds/caltech/c1/scripts was reduced from 10GB to 1.5GB

/cvs/cds/caltech/scripts_archive was cleaned up. Now the archive files are reduced to have:

  • every month 1st day from 2005 to 2018/12
  • every ten days (1, 11, 21) for 2019 and 2020
  • everyday for 2021 and 2022

(scripts)/MEDMtab/image was deleted. I can be restore back from one of the script_archive files.

(scripts)/MC/logs/AutoLocker.log was just deleted and refreshed. For the past settings, we can refer autoburt snapshots or script_archive files.


  • It turned out that the frequency of the check was reduced to once per 10min on Sep 9th, 2021 (unelogged activity).
  • The volume of the text since then was not much volume. So I deleted the lines before this date. And the file size is <7MB now.

(scripts)/ZI was moved to /cvs/cds/apps


  • 2018, 2019, 2020 snapshots were archived in tar.gz.
  • These snapshots were then deleted


  17047   Fri Jul 29 20:21:11 2022 KojiUpdatePSLFSSSlow/MCAutolocker issue (docker)

MCAutolocker/FSSSlow are not properly documented and not properly working.
Tidy up the script and documentation, or bring it back to megatron

I was aware that the FSSSlow was misbehaving since the shutdown upon the July power outage.
- FSS Slow servo did nothing even though the apparent settings in C1:PSL_SLOW screen looked fine and heart beat blinking
- Wanted to restart FSSSlow at megatron. Despite the login message showing how to do it, the system service does not exist anymore, because it was moved somewhere.
- Searched 40m wiki but found no info how to kill and restart it
- Found an elog. It was moved to docker on optimus ELOG 16480 . The restart procedure can only be found here. Please fix all the documentation inconsistency >> Anchal

According to this elog, the following commands need to be run for starting up MCAutolocker and FSSSlow on optimus:

cd /opt/rtcds/caltech/c1/Git/40m/scripts/MC
sudo docker-compose up -d

- Problem continues. Now FSSSlow is running but only when the IMC is locked. It does not stop even when the IMC lock is lost. How can we debug docker thing?
- This is minor but the MCAutolocker log (/opt/rtcds/caltech/c1/scripts/MC/logs/AutoLocker.log) is no longer updated even though MCAutolocker is running. Was it moved somewhere?


  17048   Fri Jul 29 22:37:54 2022 KojiUpdateIOOWFS investigation

I wanted to check what's wrong with the WFS.

I played with MC2 misalignment to check the error signals.
MC2 pitch and yaw misalignment optically produce a vertical translation and horizontal rotation of the cavity axis at the waist, respectively. So it is thought to be a more separated excitation of the cavity axis.
Then I noticed that WFS2 error signals in general has high (~100%) pitch-yaw coupling. So it was suspicious.

I went to the rack and found that WFS2 SEG4 RF input (labeled "8") was not completely inserted. (Attachment 1)
It seemed that the LEMO connector or the receptacle didn't latch properly anymore and could be easily pulled.
I gave some elbow grease to fix this but in vain. I ended up to use LEMO-BNC adapters which somehow offered a robust connection.

Desipite the insightful discovery, this was not the intrinsic solution to the issue. I checked the past signal history, but I don't think this loose connection caused the missing signal.

Next, I needed to go a bit deeper. The WFS sensors are supposed to be adjusted to I phase where the PDH signal maximally shows up. And all the segments are supposed to have the same sign in terms of the PDH signal.

I've unlocked the IMC and turned on MC2 tickling. This swept the cavity over the resonances.
WFS1 SEG1I~3I showed about the same waveform, but SEG4 Q shows the PDH signal rather than SEG 4 I.
Then tried the same test for WFS2. The SEG4 I signal has the sign-flipped PDH signal compared to WFS2 SEG1I-SEG3I.

I quickly adjusted the demod phase of WFS1 SEG4 and WFS2 SEG4 to correct them,

WFS1 SEG4 103.9-> -20
WFS1 SEG4 -58  -> 120

This in fact made the pitch and yaw separated but flipped (Pitch signal shows up in WFS1Y and yaw signal shows up in WFS1P. Same for WFS2)

These modifications were reverted upon my leaving.

Now things are much more subtle now. And I need to do a more careful quantitative analysis of the demodulation phases / input matrix / output matrix.

Note: It seems that I had worked on IMCWFS on Dec 21, 2016

Attachment 1: PXL_20220730_040900843.jpg
Attachment 2: PXL_20220730_041216848.jpg
  17050   Sat Jul 30 12:48:18 2022 KojiUpdatePSLFSSSlow/MCAutolocker issue (docker)

> it only starts working when C1:IOO-MC_LOCK is 1 and C1:PSL-FSS_SLOWLOOP is 1.

- OK. Your new MCAutolocker does not reflect the lock status to C1:IOO-MC_LOCK. This causes FSS Slow to go crazy when the IMC is not locked. Can you fix that?

- So C1PSL_SLOW.adl screen, which spawns by the "SLOW Servo" button on the FSS screen, has no effect on the FSS SLOW servo anymore. It is obsolete. At least the screen (or the link to the screen) should be removed. (Work on it once you are back.)

- Also, please make a wiki page and copy the description on the previous page.

  17053   Tue Aug 2 01:10:26 2022 KojiUpdateIOOWFS investigation

Continued to work on the WFS repair

Demod phase adjustment:

- Use the PDH signal to adjust the demodulation phase to have uniform signals between the segments.

- Excited laser frequency at 1234Hz by injecting 10mVpp into IMC Servo Board IN2. The input was enabled on the MC Servo screen and given the input gain of 0dB.

- Looked at the ~real time spectrum in WFS1/2 SEG1/2/3/4 I&Q after the phase rotators. Changed the demod phases 1) to have ~0deg transfer function between C1:IOO-MC_F to C1:IOO-WFSi_Ij 2) to minimize the freq signal in Q phases.
(See Attachment 1)

- Resulting change of the demod phases:

WFS1 SEG1  52.0 -> 38.0deg
WFS1 SEG2  54.0 -> 53.0deg
WFS1 SEG3  16.6 -> 33.2deg
WFS1 SEG4 103.9 ->-37.1deg

WFS2 SEG1  17.0 -> 57.8deg
WFS2 SEG2  26.6 -> 51.5deg
WFS2 SEG3  24.5 -> 44.0deg
WFS2 SEG4 -58.0 ->103.7deg

SEG4 of both WFSs had significant phase rotation. A quick check of the power spectrum indicates that the Q signals have significantly (<x1/10) lower signals (Attachment 2/3/4). So that's good.

Transfer function measurement

Now the ASCPIT/ASCYAW of the MC1/2/3 suspension were excited and the transfer functions to WFS1/2 SEG1/2/3/4 and MC Trans P/Y were measured. The analysis will come later.

Again here the Q signals have significantly lower sensitivity to the mirror motion. So it is consistent with the above observation of the spectra.

However, the quick check of the transfer functions indicated that the conventional input matrices result in the flipped dependence of the combined error signals in pitch and yaw.
This might indicate that some of the cables were not inserted into the demod board properly although the cables at the demod boards show no indication of anomaly. (See the photos in ELOG 17048)

It might be the case that the cable had been inserted with a special unusual arrangement.

In any case, this can be fixed at the input matrix. Native change of the input matrix made WFS1PIT/WFS1YAW/WFS2PIT/WFS2YAW/MC2Trans YAW servos running (after some adjustment of the servo signs).
The MC2TRANS PIT servo didn't seem to settle and run away no matter which sign is used.

It's probably better to look at the sensing matrix and figure out the proper input/output matrix carefully. So at this moment, no WFSs are working.

Note that I left the new demod phases in the system

During the transfer function measurement some filters were turned off to make the shaking smoother:

IMC ASC filters were turned off to make the FResp flat:

60Hz comb OSEM Input filters were also turned off to make the transfer functions simpler:
- MC1 INPUT FM2 OFF (60Hz comb)
- MC2 INPUT FM2 OFF (60Hz comb)
- MC3 INPUT FM2 OFF (60Hz comb)

cf. Past IMCWFS commissioning http://nodus.ligo.caltech.edu:8080/40m/12684

Attachment 1: 220801_IMC_WFS_DEMOD.pdf
Attachment 2: 220801_IMC_WFS_DEMOD2.pdf
Attachment 3: WFS1.png
Attachment 4: WFS2.png
  17055   Wed Aug 3 15:01:13 2022 KojiUpdateGeneralBorrowed Dsub cables

Borrowed DSUB cables for Juan's SURF project

- 2x D25F-M cables (~6ft?)

- 2x D2100103 ReducerCables

Attachment 1: PXL_20220803_215819580.jpg
  17059   Thu Aug 4 21:58:18 2022 KojiUpdateIOOWFS investigation

OK... It seems that all the 6 dof of the IMC WFS servo loops were closed with some condition...

- Measured the transfer functions from ASCPIT/YAW_EXC of each suspensions to WFS segs.
- FInd the proper input matrix for PIT and YAW for WFS1 and WFS2
- Closed loops one by one => This was not so successful because the loop shape was quite conditional.
- Closed WFS1/WFS2 loops one by one only with FM4 (0.8Hz Zero / (100Hz pole)^2). Adjust the gains to have the UGF at a few Hz.

- Found that the separation between WFS1P and WFS2P was not good. This caused instability of these loops when the gains were matched. I ended up lowering the gain of WFS1P by a factor of 10. This made the loop OK to work. FM3 (Integrator below 0.8Hz) worked fine.

- FM9 Rolloff filters (RLP12) makes the loops unstable.

- The MC2 spot loops (MC2_TRANS_PIT/YAW) are supposed to be slow loops. From the time series behavior it looks they are working.

MEDM Snapshots (Attchaments 1~4)

Attachment 1: Screenshot_2022-08-04_22-10-57.png
Attachment 2: Screenshot_2022-08-04_22-11-16.png
Attachment 3: Screenshot_2022-08-04_22-11-53.png
Attachment 4: Screenshot_2022-08-04_22-12-39.png
  17060   Thu Aug 4 22:14:20 2022 KojiUpdateIOOWFS investigation

Sensing matrix measurement

MCx_ASCyyy_EXC was shaken with the amplitude of 3000 cnt. Measure the transfer functions to each segment of the WFS I&Q demod outputs.

- Pitch excitations consistently indicated WFS1 SEG2&3 / SEG1&4, and WFS2 SEG 1&2 / SEG 3&4 are the pairs.
- Yaw excitations consistently indicated WFS1 SEG1&2 / SEG3&4, and WFS2 SEG 1&4 / SEG 2&3 are the pairs.

---> WFS1P matrix {1,-1,-1,1}, WFS1Y matrix {1,1,-1,-1}, WFS2P matrix {1,1,-1,-1}, WFS2Y matrix {-1,1,1,-1}

Now look at the servo input. The following lists show the important numbers for the actuation to sensor matrices. The numbers were the measured transfer function between 7~10Hz and the unit is 1/f^2 [cnt/cnt].

CHA:, C1:SUS-MC1_ASCPIT_EXC, CHB:, C1:IOO-WFS1_I_PIT_OUT, -77.4602 +/- 18.4495
CHA:, C1:SUS-MC1_ASCPIT_EXC, CHB:, C1:IOO-WFS2_I_PIT_OUT, -22.6042 +/- 5.289
CHA:, C1:SUS-MC1_ASCPIT_EXC, CHB:, C1:IOO-MC_TRANS_PIT_OUT, -0.0007949 +/- 0.00019046
CHA:, C1:SUS-MC1_ASCYAW_EXC, CHB:, C1:IOO-WFS1_I_YAW_OUT, -60.5557 +/- 14.1008
CHA:, C1:SUS-MC1_ASCYAW_EXC, CHB:, C1:IOO-WFS2_I_YAW_OUT, -206.3526 +/- 47.1332
CHA:, C1:SUS-MC1_ASCYAW_EXC, CHB:, C1:IOO-MC_TRANS_YAW_OUT, 0.00027094 +/- 6.6131e-05

CHA:, C1:SUS-MC2_ASCPIT_EXC, CHB:, C1:IOO-WFS1_I_PIT_OUT, 57.8636 +/- 35.3874
CHA:, C1:SUS-MC2_ASCPIT_EXC, CHB:, C1:IOO-WFS2_I_PIT_OUT, -185.079 +/- 104.679
CHA:, C1:SUS-MC2_ASCPIT_EXC, CHB:, C1:IOO-MC_TRANS_PIT_OUT, 0.00089367 +/- 0.00052603
CHA:, C1:SUS-MC2_ASCYAW_EXC, CHB:, C1:IOO-WFS1_I_YAW_OUT, -349.7898 +/- 202.967
CHA:, C1:SUS-MC2_ASCYAW_EXC, CHB:, C1:IOO-WFS2_I_YAW_OUT, -193.7146 +/- 111.2871
CHA:, C1:SUS-MC2_ASCYAW_EXC, CHB:, C1:IOO-MC_TRANS_YAW_OUT, 0.003911 +/- 0.0023028

CHA:, C1:SUS-MC3_ASCPIT_EXC, CHB:, C1:IOO-WFS1_I_PIT_OUT, 65.5405 +/- 14.305
CHA:, C1:SUS-MC3_ASCPIT_EXC, CHB:, C1:IOO-WFS2_I_PIT_OUT, 78.8535 +/- 17.1719
CHA:, C1:SUS-MC3_ASCPIT_EXC, CHB:, C1:IOO-MC_TRANS_PIT_OUT, -0.00087661 +/- 0.00020837
CHA:, C1:SUS-MC3_ASCYAW_EXC, CHB:, C1:IOO-WFS1_I_YAW_OUT, -130.7286 +/- 29.6898
CHA:, C1:SUS-MC3_ASCYAW_EXC, CHB:, C1:IOO-WFS2_I_YAW_OUT, 129.0654 +/- 28.6328
CHA:, C1:SUS-MC3_ASCYAW_EXC, CHB:, C1:IOO-MC_TRANS_YAW_OUT, -0.00024944 +/- 5.9112e-05

Put these numbers in the matrix calculation and take the inverse for pitch and yaw separately.

We obtained

WFS1P    WFS2P    MCTP    
-4.017   -4.783   -7.306e5   MC1P
 3.611   -5.252   -2.025e5   MC2P
 7.323   -1.017   -6.847e5   MC3P

WFS1Y    WFS2Y    MCTY    
-3.457   -4.532   -5.336e5   MC1Y
-0.1249   0.3826   2.635e5   MC2Y
-5.714    1.076   -4.578e5   MC3Y

Basically we can put these numbers into the output matrix. The last column corresponds to the spot position servo and we want to make this slow.
So used x1e-5 values (i.e. removed e5) instead of these huge numbers.


Attachment 1: IMC_SUS_channels_TF.pdf
Attachment 2: IMC_WFS_channels_TF.pdf
Attachment 3: IMC_WFS_segment_TF.pdf
Attachment 4: IMC_WFS_220804.xlsx
  17061   Thu Aug 4 22:14:38 2022 KojiUpdateIOOWFS investigation


Attachment 1: HEPA ON

WFS1/2 PIT/YAW Spectra are stabilized below 1Hz (0.1Hz for WFS1P)

MC2 TRANS PIT is largely contaminated by the other WFS loops.
MC2 TRANS YAW is slightly contaminated but not much compared to the one for pitch.

Attachment 2: HEPA OFF

Again, WFS1/2 PIT/YAW Spectra are stabilized below 1Hz (0.1Hz for WFS1P)

MC2 TRANS PIT is still contaminated but better.
MC2 TRANS YAW is not contaminated.


WFS1/2 signals are largely disturbed when PSL HEPA is ON. Probably the amount of HEPA air flow was not optimized.
Above 1Hz, invacuum suspension are quieter than the beam incident on the IMC.

The dirty WFS signals are fedback to the mirrors. Due the large motion of the beam and also the imperfection of the actuator matrix cause the MC2 spot rather moves than stabilized.

This means that the WFS loops should leave the mirrors untouched above 1Hz i.e. The loop bandwidths should be low (~<0.1Hz). (Yes I know)
However, the simple gain reduction (x10) does make the servos unstable. So more adjustment is necessary. (<-Not for today)

Attachment 1: Screenshot_2022-08-04_22-17-19.png
Attachment 2: Screenshot_2022-08-04_22-18-45.png
  17062   Thu Aug 4 22:32:31 2022 KojiUpdateIOOUpon leaving the lab (WFS investigation)

Upon leaving the lab:

- HEPA is ON at the original speed (i.e. same speed at 5PM today)

- WFS servo is ON, partly because we want to see how stable it is. It is not handled with the autolocker right now.
So there is a possibility that the WFS servo goes wild and make the IMC totally misaligned (and does not come back)
In such a case, go to the WFS servo screen and push "CH" (clear history) of each servo filters.

  17063   Fri Aug 5 12:42:12 2022 KojiUpdateIOOIMC WFS: Overnight observation

The IMC lock survived overnight and the WFS servo loops kept it aligned. The IMC was unlocked in the morning.
The left 6 plots are the WFS servo outputs and the right most two plot show the transmission and reflection of the IMC.

If the WFS is making the lock unstable under high seismic conditions, please turn the loops off.


Attachment 1: Screen_Shot_2022-08-05_at_12.04.01.png
  17068   Tue Aug 9 15:50:22 2022 KojiUpdateBHDBHD fringe contrast improved from 43% to 74%

For both 40m/17020 and 40m/17024, what does the contrast mean if the numbers are leaking out to ~-100cnt?
Also how much is it if you convert this contrast into the mode matching?

  17072   Wed Aug 10 19:36:45 2022 KojiBureaucracyGeneralLab cleaning and discovery

During the cleaning today, we found many legacy lab items. Here are some policies what should be kept / what should be disposed


  • VME crates and VME electronics as long as they are not in use
  • Eurocard SUS modules that are not in use.
  • Eurocard crates (until we remove the last Eurocard module from the lab)
  • Giant steel plate/palette (like a fork lift palette) along the Y arm. (Attachment 1)
  • An overhead projector unit.


  • Spare Eurocard crates / ISC/PZT Eurocard modules
  • Boxes of old 40m logbooks behind the Y arm (see Attachment 2/3).
  • Ink-plotter time-series data (paper rolls) of 1996 IFO locking (Attachment 4). Now stored in a logbook box.
  • A/V type remnants: Video tapes / video cameras / casette tapes as long as they hold some information in it. i.e. Blank tapes/blank paper rolls can be disposed.
Attachment 1: steel_plate.jpg
Attachment 2: logbook1.jpg
Attachment 3: logbook2.jpg
Attachment 4: paper_plots.jpg
  17077   Fri Aug 12 02:02:31 2022 KojiUpdateGeneralPower Outage Prep: nodus /home/export backup

Took the backup (snapshot) of /home/export as of Aug 12, 2022

controls@nodus> cd /cvs/cds/caltech/nodus_backup
controls@nodus> rsync -ah --progress --delete /home/export ./export_220812 >rsync.log&

As the last backup was just a month ago (July 8), rsync finished quickly (~2min).

  17079   Mon Aug 15 10:27:56 2022 KojiUpdateGeneralRecap of the additional measures for the outage prep

[Yuta Koji]

(Report on Aug 12, 2022)

We went around the lab for the final check. Here are the additional notes.

  • 1X9: The x-end frontend machine still had the AC power. The power strip to which the machine is connected was disconnected from the AC at the side of the rack. (Attachment 1)
  • 1X8: The vacuum rack still supplied the AC to c1vac. This was turned off at the UPS. (Attachment 2)
  • 1X6: VMI RFM hub still had the power. This was turned off at the rear switch. (Attachment 3)
  • PSL: The PSL door was open (reported above). Closed. (Attachment 4)
  • 1Y2: The LSC rack still had the DC power. The supplies were turned off at the KEPCO rack (the short rack). (Attachment 5)
    Note that the top-right supply for the +15V is not used. (The one in the empty slot got busted). We may need some attention to the left-most one in the second row. It indicated a negative current. Is this just the current meter problem or is the supply broken?
  • Control room: The CAD WS was turned off.

I declare that now we are ready for the power outage.

Attachment 1: PXL_20220812_234438097.jpg
Attachment 2: PXL_20220812_234655309.jpg
Attachment 3: PXL_20220812_234748559.jpg
Attachment 4: rn_image_picker_lib_temp_b5f3e38d-796c-4816-bc0e-b11ba3316cbe.jpg
Attachment 5: PXL_20220812_235429314.jpg
  17082   Mon Aug 15 20:09:18 2022 KojiUpdateGeneralc1vac issues, 1 pressure gauge died

- Disk Full: Just use the usual /etc/logrotate thing

- Vacuum gauge

I rather feel not replacing P1a. We used to have Ps and CCs as they didn't cover the entire pressure range. However, this new FRG (=Full Range Gauge) does cover from 1atm to 4nTorr.

Why don't we have a couple of FRG spares, instead?

Questions to Tega: How many FRGs can our XGS-600 controller handle?


  17084   Wed Aug 17 01:18:54 2022 KojiUpdateGeneralNotice: SURF SUS test setup blocking the lab way

Juan and I built an analog setup to measure some transfer functions of the MOS suspension. The setup is blocking the lab way around the PD test bench.
Excuse us for the inconvenience. It will be removed/cleared by the end of the week.

Attachment 1: PXL_20220817_060428109.jpg
  17091   Thu Aug 18 18:10:49 2022 KojiSummaryLSCFPMI Sensitivity

The overlapping plot of the calibrated error and control signals gives you an approximately good estimation of the freerun fluctuation, particularly when the open-loop gain G is much larger or much smaller than the unity.
However, when the G is close to the unity, they are both affected by "servo bump" and both signals do not represent the freerun fluctuation around that frequency.

To avoid this, the open-loop gain needs to be measured every time when the noise budget is calculated. In the beginning, it is necessary to measure the open-loop gain over a large frequency range so that you can refine your model. Once you gain sufficient confidence about the shape of the open-loop gain, you can just use measurement at a frequency and just adjust the gain variation (most of the cases it comes from the optical gain).

I am saying this because I once had a significant issue of (project-wide) incorrect sensitivity estimation by omitting this process.

  17093   Fri Aug 19 15:20:14 2022 KojiUpdateGeneralNotice: SURF SUS test setup blocking the lab way

The setup was (at least partially) cleared.

Attachment 1: PXL_20220819_201318044.jpg
  17095   Fri Aug 19 15:36:10 2022 KojiUpdateGeneralSR785 C21593 CHA+ BNC broken

When Juan and I were working on the suspension measurement, I found that CHA didn't settle down well.

I inspected and found that CHA's + input seemed broken and physically flaky. For Juan's measurements, I plugged + channels (for CHA/B) and used - channels as an input. This seemed work but I wasn't sure the SR functioned as expected in terms of the noise level.

We need to inspect the inputs a bit more carefully and send it back to SRS if necessary.

How many SR785's do we have in the lab right now? And the measurement instruments like SR785 are still the heart of our lab, please be kind...

Attachment 1: PXL_20220819_195619620.jpg
Attachment 2: PXL_20220819_195643478.jpg
  17114   Wed Aug 31 00:32:00 2022 KojiUpdateGeneralSOS and other stuff in the clean room

Salvage these (and any other things). Wrap and double-pack nicely. Put the labels. Store them and record the location. Tell JC the location.

Attachment 1: PXL_20220831_015137480.jpg
Attachment 2: PXL_20220831_015203941.jpg
Attachment 3: PXL_20220831_015230288.jpg
Attachment 4: PXL_20220831_015249451.jpg
Attachment 5: PXL_20220831_015424383.jpg
Attachment 6: PXL_20220831_015433113.jpg
  17115   Wed Aug 31 00:46:56 2022 KojiUpdateGeneralVertex Lab area to be cleaned

As marked up in the photos.


Attachment 5: The electronics units removed. Cleaning half way down. (KA)

Attachment 6: Moved most of the units to 1X3B rack ELOG 17125 (KA)

Attachment 1: PXL_20220831_015758208.jpg
Attachment 2: PXL_20220831_015805113.jpg
Attachment 3: PXL_20220831_015816628.jpg
Attachment 4: PXL_20220831_015826533.jpg
Attachment 5: PXL_20220831_015844401.jpg
Attachment 6: PXL_20220831_015854055.jpg
Attachment 7: PXL_20220831_015903704.jpg
Attachment 8: PXL_20220831_015919376.jpg
Attachment 9: PXL_20220831_021708873.jpg
  17116   Wed Aug 31 01:22:01 2022 KojiUpdateGeneralAlong the X arm part 1


Attachment 5: RF delay line was accommodated in 1X3B. (KA)

Attachment 1: PXL_20220831_015945610.jpg
Attachment 2: PXL_20220831_020024783.jpg
Attachment 3: PXL_20220831_020039366.jpg
Attachment 4: PXL_20220831_020058066.jpg
Attachment 5: PXL_20220831_020108313.jpg
Attachment 6: PXL_20220831_020131546.jpg
Attachment 7: PXL_20220831_020145029.jpg
Attachment 8: PXL_20220831_020203254.jpg
Attachment 9: PXL_20220831_020217229.jpg
  17117   Wed Aug 31 01:24:48 2022 KojiUpdateGeneralAlong the X arm part 2



Attachment 1: PXL_20220831_020307235.jpg
Attachment 2: PXL_20220831_020333966.jpg
Attachment 3: PXL_20220831_020349163.jpg
Attachment 4: PXL_20220831_020355496.jpg
Attachment 5: PXL_20220831_020402798.jpg
Attachment 6: PXL_20220831_020411566.jpg
Attachment 7: PXL_20220831_020419923.jpg
Attachment 8: PXL_20220831_020439160.jpg
Attachment 9: PXL_20220831_020447841.jpg
  17118   Wed Aug 31 01:25:37 2022 KojiUpdateGeneralAlong the X arm part 3



Attachment 1: PXL_20220831_020455209.jpg
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  17119   Wed Aug 31 01:30:53 2022 KojiUpdateGeneralAlong the X arm part 4

Behind the X arm tube

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  17120   Wed Aug 31 01:53:39 2022 KojiUpdateGeneralAlong the Y arm part 1



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  17121   Wed Aug 31 01:54:45 2022 KojiUpdateGeneralAlong the Y arm part 2
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  17125   Wed Aug 31 16:11:37 2022 KojiUpdateGeneralVertex Lab area to be cleaned

The analog electronics units piled up along the wall was moved into 1X3B rack which was basically empty. (Attachments 1/2/4)

We had a couple of unused Sun Machines. I salvaged VMIC cards (RFM and Fast fiber networking? for DAQ???) and gave them to Tega.
Attachment 3 shows the eWastes collected this afternoon.

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  17162   Wed Sep 28 19:15:56 2022 KojiUpdateGeneralTesting 950nm laser found in trash pile

I don't know what was wrong with the past setup but the 950nm laser (QPHOTONICS QFLD-950-3S) just worked fine up to ~300MHz with basically the same setup.

A 20dB coupler picks up a small amount of the driving signal from the source signal of the network analyzer. This was fed to CHR. The fiber-coupled NewFocus PD RF output was connected to CHA.
The calibration of the response was done with the thru response (connect the source signal to the CHA via all the long cables).

Attachment 1 shows the response CHA/CHR. The output is somewhat flat up to 20MHz and goes down towards 100MHz, but still active up to 500MHz as long as the normalization with the New Focus PD works.
The structure around 200MHz~300MHz changes with how the wires of the clips are arranged. I have twisted and coiled them as shown and the notch disappeared. For the permanent setup we should keep the lines as short as possible and take care of the stray capacitance and the inductance.

Attachment 2 shows the setup at the network analyzer side. Nothing special.

Attachment 3 shows the setup at the laser side. The DB9 connector on the Jenne's laser has the negative output of the LD driver connected to the coax core and the positive output connected to the shield of the coax. Therefore the coax core (red clip) has to be connected to Pin 9 and the coax shield (black clip) to PIn 5.

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  17177   Fri Oct 7 20:00:46 2022 KojiUpdateIOOIMC WFS / MC2 SUS glitch

After the CDS upgrade team called for a day (their work TBD), I took over the locked IMC to check how it looked like.

The lock was robust but the IMC REFL spot and the WFS DC/MC2 QPD were moving too much.
I wondered if there were something wrong with the damping. I thought MC3 damping seemed weak, but this was torelable level.LR
During the ring down check of MC2, I saw that the OSEM signals were glitchy. In the end I found it was LR sensor which was glitchy and fluctuating.

I went into the lab and pushed the connectors on the euro card modules and the side connectors as well as the cables on the MC2 sat amp.
I came back to the control room and found the MC2 LR OSEMs had the jump and it seems more stable now.

I leave the IMC locked & WFS running. This sus situation is not great at all and before we go too far, we'll work on the transition to the new electronics (but not today or next week).

By the way the unit of the signals on the dataviewer didn't make sense. Something seemed wrong with them.

Attachment 1: Screenshot_2022-10-07_19-59-45.png
  17179   Sun Oct 9 13:49:49 2022 KojiUpdateIOOIMC WFS / MC2 SUS glitch

The IMC and the IMC WFS kept running for ~2days. 👍

I wanted to look at the trand of the IMC REFL DC, but the dataviewer showed that the recorded values are zero. And this slow channel is missing in the channel list.

I checked the PSL PMC signals (slow) as an example, and many channels are missing in the channel list.

So something is not right with some part of the CDS.

Note that I also reported that the WFS plot in the above refered previous elog has the value like 1e39


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  17183   Tue Oct 11 11:27:58 2022 KojiUpdateCDSCDS Upgrade remaining issues

Perhaps 1PPS around the PSL was used for the Rb standard to be locked to the GPS 1PPS.

If we need to drive multiple devices, we should use a fanout circuit to avoid distorting the 1PPS. -CW

  17188   Thu Oct 13 19:06:42 2022 KojiUpdateLab OrganizationLab Cleanup 10/12/2022

I have moved the following electronics / components to "Section Y10 beneath the tube"

  • IQ Demod Spares D0902745 (Components)
  • Sat Box / HAM-A 40m parts D08276/D110117
  • 16bit DAC AI Rear PCB D070101-v3
  • D1900163 HV COIL DRIVER
  • Ribbon Cables for Chassis (Cardboard box)
  • Chassis DC Breaker Switches (Cardboard box)
  • Triplett HDMI displays (x3) / Good for portable CCD monitors / PC monitors. Battery powered!
  • ISC Whitening BI Config Boards D1001631/D1900166
  • AA/AI Untested D070081
  • WFS Interface / Soft Start D1101865/D1101816
  • Internal Wiring Kit Cable Spools
  • ISC Whitening / Interface D1001530 / D1002054
  • aLIGO WFS Head D1101614
  • Internal Wiring Kit (Large Plastic Box)
  • Front/Rear Panels (Large Plastic Box)
  • HV Coil Driver Test Kit / Spare PA95s (Large Plastic Box)


  17190   Thu Oct 13 23:52:45 2022 KojiUpdateIMCIMC ASC: summary pages and notes

The output matrices have been calculated on Aug 4, 2022 by me. [40m ELOG 17060]

Regarding the noise see [40m ELOG 17061]

With regard to the current IMC WFS design, a SURF student in 2014 (Andres Medina) and Nick Smith made the revision.
The telescope design was described in the elogs [40m ELOG 10410] [40m ELOG 10427] and also T1400670.

  17210   Tue Oct 25 13:55:37 2022 KojiConfigurationPEMAuto Z on trillium interface board

This nicely brought the sensing signal back to ~zero. See attachment

Some basic info:

  • BS Seismometer is T240 (Trillium)
  • The interface unit is at 1X5 Slot 26. D1002694
  • aLIGO Trillium 240 Interface Quick Start Guide T1000742
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  17214   Tue Oct 25 22:24:46 2022 KojiUpdateIOOHEPA OFF / WFS OFF

Turned HEPA OFF / Lab Lights OFF / WFS Input Gain switched off for the IMC WFS signal tests.
The IMC is still well aligned.

Clean data from the following time:
2022/10/26 5:24:00 UTC (10/25 22:24 PDT)
GPS 1350797056


  17217   Mon Oct 31 21:04:43 2022 KojiUpdateASCWFS inspection

Inspected the lab to see what we can do about the IFO WFS:

  • WFS heads
    • 1 functional WFS head (tuned at 11/55MHz) @AS Table [40m ELOG 15736]
    • 1 WFS head case (empty) @Section Y10 below the tube, plastic box
    • 2 WFS PCBs, components stuffed, tuning freq unknown @Section Y10 below the tube, plastic box
  • Deomdulators
    • no 4ch IQ demod unit (some component possibly spare)
    • Build 4 iLIGO demods?
  • Whitening / AA
    • No permanent unit: Maybe we can borrow something from the BHD
  • ADC CHs
    • c1ioo seems to have just 8 more spare channels.
    • Borrow a card from bhd? This will require an AI. But their location would be close to the final positions.
  17233   Mon Nov 7 12:37:26 2022 KojiUpdateGeneralBorrowed the fiber tester for the OMC lab

I am borrowing the fiber illuminator / fiber tester / VisiFault for the OMC lab. It has been stored in the top drawer at the center work bench.

==> Returned

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  17305   Wed Nov 23 16:34:33 2022 KojiUpdateCDSNew donatella testing

Let's use this entry to list of the test results of new donatella.

  • Firefox - OK (typing elog now)
  • sitemap - OK
  • Diaggui (DTT) looks working fine for the current and past data
  • Dataviewer looks working fine for the current and past (slow/fast) data
  • ndscope - fine
  • foton - works fine
  • burtgooey - ?
  13941   Mon Jun 11 18:10:51 2018 Koji UpdateelogComparison of the analytical and finesse values of TMS and FSR.

Hmm? What is the definition of the percentage error? I don't obtain these numbers from the given values.
And how was the finesse value obtained from the simulation result? Then what is the frequency resolution used in Finesse simulation?

  2613   Thu Feb 18 15:39:16 2010 Koji and SteveConfigurationVACvalve condition: ALL OFF

As preparation for the upcoming planned power outage we turned turbos, RGA off and closed valves.

IFO chamber is not pumped now. Small leaks and out gassing will push the pressure up slowly. At 3 mTorr of P1 the PSL output shutter

will be closed by the interlock.

It is OK to use light in the IFO up to this point.

  7736   Wed Nov 21 01:31:37 2012 Koji, AyakaUpdateLockingalignment on ETMX table

Since the transmission beam on ETMXT camera seemed to be clipped, we checked the optics on ETMX table.

We aligned the lens so that it is orthogonal to the beam, then the beam shape looks fine.


Also we removed some an-used optics which were used for fiber input.

  2259   Thu Nov 12 17:24:29 2009 Koji, Joe, PeterConfigurationCDSETMY CDS test started

We started the test of the new CDS system at ETMY.

The plan is as follows:
We do the ETMY test from 9:30 to 15:00 at ETMY from Nov 12~17. This disables the ETMY during this period.
From 15:00 of the each day, we restore the ETMY configuration and confirm the ETMY work properly.

Today we connected megatron to the existing AA/AI modules via designated I/F boxes. The status of the test was already reported by the other entry.

During the test, c1iscey was kept running. We disabled the ETMY actuation by WatchDog. We did not touch the RFM network.

After the test we disconnected our cables and restored the connection to ICS110B and the AI/AA boards.

The WatchDog switches were released.

The lock of the ETMY was confirmed. The full interferometer was aligned one by one. Left in the full configuration with LA=off.

  3054   Tue Jun 8 00:38:22 2010 Koji, KiwamuUpdateIOOimproved Gaussian beam in new IOO

The shape of the beam spot in the new input optics got much much better 

As Alberto and Kiwamu found on the last week, the beam spot after MMT1 had not been good. So far we postponed the mode measurement due to this bad beam profile.

Today after we did several things in the vacuum chamber, the beam spot became really a good Gaussian spot. See the attachment below.

There were two problems which had caused the bad profile:

(1)  a steering mirror after MMT1 with the incident angle of non 45 deg

(2) clipping at the Faraday.


Also MCT_QPD and MCT_CCD were recovered from misalignment  

Tomorrow we are going to restart the mode matching. 


(what we did)

* We started from checking the shape of the beam going out from the BS chamber. There still were some stripes which looked like an interference on the spot. 

* We found a steering mirror after MMT1 had the incident angle of non 45 deg. In fact the mirror had a large transmission. After we made the angle roughly 45 deg, the stripes disappeared.

However the spot still didn't look a good Gaussian, it looked slightly having a bump on the horizontal profile.

* Prior to moving of some optics in the vacuum, we ran the A2L_MC scripts in order to check the beam axis. And it was okay.

* To recover the MCT, we steered one of the vacuum mirrors which was located after the pick off mirror.  And after aligning some optics on the AP table, finally we got MCT recovered.

 * We rearranged MC_refl mirrors according to the new optical layout that Koji has made. At the same time the mirrors for IFO_refl was also rearranged coarsely.

 * We leveled the optical table of the MC chamber by moving some weights. Then we locked the MC again and aligned it. We again confirmed that the beam axis was still fine by running the A2L scripts.

 * We found the beam going through Faraday was off-centered by ~5mm toward the west. So we moved it so that the beam propagates on the center of it. 

 * Then looking at the beam profile after MMT1, we found that the profile became really nicer. It showed a beautiful Gaussian. 

In the attachment below, the top panel represents the horizontal profile and the bottom one represents the vertical profile.

The blue curves overlaid on the plot are fitted Gaussian profile, showing beautiful agreements with the measured profile.

Attachment 1: 2010-6-7_2.png
  2915   Wed May 12 02:35:13 2010 Koji, Rana, KiwamuUpdateGreen LockingReflection from ETM and ITM !

We succeeded in getting the reflected green beam from both ITMY and ETMY.

After we did several things on the end table, we eventually could observe these reflections.

Now the spot size of the reflection from ITMY is still big ( more than 1 cm ), so tomorrow modematching to the 40m cavity is going to be improved by putting mode matching telescopes on right positions.

An important thing we found is that, the beam height of optics which directly guides the beam to the cavity should be 4.5 inch on the end table.


(what we did)

* Aidan, Kevin and Kiwamu set the beam to be linearly polarized by rotating a QWP in front of the Innolight. This was done by monitoring the power of the transmitted light from the polarizer attached on the input of the Faraday of 1064 nm. Note that the angle for QWP is 326.4 deg.

* We put some beam damps against the rejected beam from the Faraday

* To get a good isolation with the Faraday we at first rotated the polarization of the incident beam so to have a minimum transmission. And then we rotated the output polarizer until the transmission reaches a minimum. Eventually we got the transmission of less than 1mW, so now the Faraday should be working regardless of the polarization angle of the incident beam. As we predicted, the output polaerizer seems to be rotated 45 deg from that of the input.

* Rana, Koji and Kiwamu aligned the PPKTP crystal to maximize the power of 532 nm.  Now the incident power of 1064 nm is adjusted to 250mW and the output power for 532 nm is 0.77mW. Actually we can increase the laser power by rotating a HWP in front of the Faraday.

* We injected the green beam to the chamber and aligned the beam axis to the ETMY without the modematching lenses, while exciting the horizontal motion of the ETM with f=1Hz from awg. This excitation was very helpful because we could figure out which spot was the reflection from the ETM.

* Once we made the reflected beam going close to the path of the incident beam, we then put the modematching lenses and aligned the steering mirrors and lenses. At this time we could see the reflected beam was successfully kicked away by the Faraday of 532 nm.

* Koji went to ITMY chamber with a walkie-talkie and looked at the spot position. Then he told Rana and Kiwamu to go a right direction with the steering mirrors. At last we could see a green beam from ITM illuminating the ETM cage.

* We excited the ITMY with f=2Hz vertically and aligned the ITM from medm. Also we recovered a video monitor which was abandoned around ETMY chamber so that we could see the spot on the ETM via the monitor. Seeing that monitor we aligned the ITM and we obtained the reclection from the ITM at the end table.

* We also tried to match the mode by moving a lens with f=400mm, but we couldn't obtain a good spot size.


  2290   Wed Nov 18 11:27:33 2009 Koji, josephbConfigurationSUSETMY suspension conencted to megatron ADC/DAC


Koji, Rana

The megatron DAC was temporaly connected to the suspension electronics for the DAC test. We went down to ETMY as we could not excite the mirror.

The DAC is putting correct voltages to the channels. However, the anti imaging filter test output does not show any signal.
This means something wrong is there in the DAC I/F box or the cables to the AI circuit. We will check those things tomorrow.

The ETMY was restored to the usual configuration.


It appears the front panel for the DAC board is mis-labeled.  Channels 1-8 are in fact 9-16, and 9-16 are the ones labeled 1-8.  We have put on new labels to reduce confusion in the future.

ELOG V3.1.3-