I ran my damp_regression_compare script (85369) on the suspensions that we swapped the satellite amplifiers for today, BS, PRM, PR3, SRM, and SR3. The results show a decrease in the OSEM noise of at least 2x!

Part of what the script does is save the channel data as a .mat file so it's quicker to run next time, so I'll post that as well as the results.

On Tuesday Fil swapped the sat amps for ITMX, ITMY, and SR2 (85619). Like I did for the first set of satamp swaps (85485), I've used my damp_regression_compare script found in sustrunk to compare the noise performance (85369).

ITMX
M0
Results: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGM0/Results/allDampRegressCompare_H1SUSITMX_M0_NoiseComparison_1435482383vs1436080373-1200.pdf
         r12442
Data: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGM0/Data/dampRegress_H1SUSITMX_M0_1435482383_1200.mat
      /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGM0/Data/dampRegress_H1SUSITMX_M0_1436080373_1200.mat
      r12442
R0
Results: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGR0/Results/allDampRegressCompare_H1SUSITMX_R0_NoiseComparison_1435482383vs1436080373-1200.pdf
         r12443
Data: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGR0/Data/dampRegress_H1SUSITMX_R0_1435482383_1200.mat
      /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMX/SAGR0/Data/dampRegress_H1SUSITMX_R0_1436080373_1200.mat
      r12443

ITMY
M0
Results: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGM0/Results/allDampRegressCompare_H1SUSITMY_M0_NoiseComparison_1435482383vs1436080373-1200.pdf
         r12444
Data: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGM0/Data/dampRegress_H1SUSITMY_M0_1435482383_1200.mat
      /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGM0/Data/dampRegress_H1SUSITMY_M0_1436080373_1200.mat
      r12444
R0
Results: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGR0/Results/allDampRegressCompare_H1SUSITMY_R0_NoiseComparison_1435482383vs1436080373-1200.pdf
         r12445
Data: /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGR0/Data/dampRegress_H1SUSITMY_R0_1435482383_1200.mat
      /ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ITMY/SAGR0/Data/dampRegress_H1SUSITMY_R0_1436080373_1200.mat
      r12445

SR2
Results: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SR2/SAGM1/Results/allDampRegressCompare_H1SUSSR2_M1_NoiseComparison_1435482383vs1436080373-1200.pdf
         r12446
Data: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SR2/SAGM1/Data/dampRegress_H1SUSSR2_M1_1435482383_1200.mat
      /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SR2/SAGM1/Data/dampRegress_H1SUSSR2_M1_1436080373_1200.mat
      r12446

23:57 UTC lockloss

TITLE: 07/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Two locklosses this shift, but recovery so far has been straightforward. H1 is currently relocking and up to MAX_POWER.

• 15:41 - Lockloss - alog85685
  • 17:06 - Lockloss during LOWNOISE_ASC
• 18:00 - Observing
• 22:23 - Lockloss - alog85697

LOG:

TITLE: 07/11 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 6mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.12 μm/s
QUICK SUMMARY:

• We are still trying to recover and lock DRMI after a 22:23 UTC lockloss
• 2ndary microseism is increasing
• Wind is low

Lockloss @ 22:23 UTC after 4.5 hours locked - link to lockloss tool

No obvious cause, but ETMX starts moving strangely about a half a second before the lockloss.

We grabbed the measurement data that Oli generated on [LHO: 85288] which was taken using the calibrated OSEMINF gains that we obtained by driving the ISI an looking at the OSEM response at high frequencies [see LHO: 84367].

The TL;DR is that the calibration works:

• The diagonal elements of the measured and modeled plants now match.
• The measured TFs are a bit more symmetric.
• We see the expected reduction in cross-couplings to Roll and Pitch.

The .pdf attached can be found in

https://svn.ligo.caltech.edu/svn/sus/trunk/HLTS/H1/SR3/SAGM1/Results/2025-06-24_1900_H1SUSSR3_M1_ALL_TFs.pdf

We can see that the diagonal M1 to M1 modeled and measured transfer functions actually match one another much better than before (for an example uncalibrated plot, click here to see April 2025). This happens even though the calibration did not involve M1 to M1 transfer functions.

We can assess the impact that the calibration had on the M1 to M1 cross-couplings by plotting a normalized version of the cross-coupled transfer functions. For example, the Length-Pitch normalized transfer function will be (L2P)_norm=(L2P)/sqrt(P2P*L2L).

This way we can get rid of the overall scaling factors that come from the OSEM calibration and focus on the cross-coupling. The result is shown in the second attachment. The columns correspond to M1 drives, and the rows are OSEM displacements, all plots are dimensionless. The blue trace is after OSEM calibration, and red is before OSEM calibration, and from 2024/08/08 to avoid the gains that were in the yaw and pitch TEST drive paths in the more recent data [see LHO: 84259].

The cross-couplings of=n this last plot can be broken down into 4 general types of cross-couplings:

1) Things that don't change much (L2T, L2P, etc)- Nothing to say.

2) Cross couplings that improve quite a bit with the calibration. [V2R, V2P R2V, and R2P]. This were what we expected from the original calibration procedure. Especially cross-couplings involving the Roll degree of freedom were expected to improve.

3) Cross couplings that got a bit worse, but were expected [Y2R, Y2V, L2V, and L2R]. These are related to the fact that the average calibration for the LF and RT OSEMs is very different for the three osems atop the suspension T1, T2, and T3. The cross-coupling is not higher, it's just a normalization quirk.

4) Cross-coupling that got worse and was unexpected. Only P2R fits this category. The calibration should make the plant more symmetric, so it is at least good that P2R and R2P seem more similar now. Since the coupling that's changing is going to Roll, we believe this is actually more accurate to the underlying Pitch-Roll plant compared to the results from before.

The next steps for this work are to semi-automate the calibration process, and to methodically deploy the calibration to other suspensions now that the SatAmp work has been done.

We have finally confirmed that the current BBSS build is stable for both LHO and LLO, and we have figured out the model parameter set that matches the builds, so I've finally gone ahead and merged the parameter changes from the parameter set we had been using as the default for a while, bbssopt_2025_d0plus3p0_l1mins3p0_m2plus0p3_FDRd1plus3p5.m, into bbssopt.m (r12435). The differences between the original FDR parameter set (from T2000599-v1) and this hopefully final set are as follows:

• d4 -= 1e-3         Adjustment to get better fit to measurements 76071, 82138
• l3 -= 4.5e-3    Loop length change 79004
• d1 += 3.5e-3    Equal to blade position = -4mm
• m2 += 0.3           Mass added to M2
• d0 += 3e-3       Height change of added spacer
• l1 -= 3e-3      Wire length change to counter height added by spacer

I have used my compareallbbss_tfs.m script (CSWG:11252) to make comparison plots between the BSFM, the original FDR parameter set from T2000599-v1, and this parameter set. This parameter set has been uploaded to T2000599 as -v4.

Here are the latest H1 safety results from the November 2024 injections (sorry for the very long delay): https://drive.google.com/drive/folders/1CgwhWlKpG9CFnaiLvHnF2bWZVyHMN4gz?usp=sharing. It'd be great if folks could take a quick scroll through this spreadsheet (sorted by statistically most unsafe at the top) and see if there are any channels which have been determined to be unsafe (column F) which shouldn't be, or if there are any that should be added to the channel lists. Thanks!

Fri Jul 11 10:07:27 2025 INFO: Fill completed in 7min 24secs

Jordan confirmed a good fill curbside.

Closes FAMIS#28462 , last checked 84837

CO2 Trends (ndscope1)

Everything is looking good

HWS Trends (ndscope2)

Everything is generally looking good, with both ITMX and ITMY SLEDPOWERMON slowly going down, which they tend to do. The only possible concern I can see would be that zooming out to almost a year ago (ndscope3), it looks like the level that ITMX SLEDPOWERMON is at now is a lower value than it has been in the past year.

Since we had a few PI-caused locklosses last week, we realized that the PI monitor (PIMON) didn't seem to be running properly and saving the data 524 kHz DCPD data at the end of the lock. TJ has been trying to debug the issue. In the meantime, I have left PIMON running on a control room computer that I am logged into, and the lockloss data is being saved into /ligo/gitcommon/labutils/PIMON/locklosses and the script plot_locklosses.py in /ligo/gitcommon/labutils/PIMON can be used to plot the data from the locklosses.

Fortunately, we haven't had any PI locklosses that we know of since last week. Whenever control room computers are rebooted, we need to restart the script.

Lockloss @ 15:41 UTC after 18 hours locked - link to lockloss tool

No obvious cause that I can see.

I ran my damp_regression_compare script (85369) on the suspensions that we swapped the satellite amplifiers for today, BS, PRM, PR3, SRM, and SR3. The results show a decrease in the OSEM noise of at least 2x!

Part of what the script does is save the channel data as a .mat file so it's quicker to run next time, so I'll post that as well as the results.

BS
Results: /ligo/svncommon/SusSVN/sus/trunk/BSFM/H1/BS/SAGM1/Results/allDampRegressCompare_H1SUSBS_M1_NoiseComparison_1435348334vs1435435046-1200.pdf
      r12374
Data: /ligo/svncommon/SusSVN/sus/trunk/BSFM/H1/BS/SAGM1/Data/dampRegress_H1BS_M1_1435348334_1200.mat
     /ligo/svncommon/SusSVN/sus/trunk/BSFM/H1/BS/SAGM1/Data/dampRegress_H1BS_M1_1435435046_1200.mat
    r12373

PRM
Results: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/SAGM1/Results/allDampRegressCompare_H1SUSPRM_M1_NoiseComparison_1435348334vs1435435046-1200.pdf
      r12376
Data: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/SAGM1/Data/dampRegress_H1PRM_M1_1435435046_1200.mat
     /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/SAGM1/Data/dampRegress_H1PRM_M1_1435348334_1200.mat
     r12375

PR3
Results: /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/PR3/SAGM1/Results/allDampRegressCompare_H1SUSPR3_M1_NoiseComparison_1435348334vs1435435046-1200.pdf
      r12380
Data: /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/PR3/SAGM1/Data/dampRegress_H1PR3_M1_1435348334_1200.mat
     /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/PR3/SAGM1/Data/dampRegress_H1PR3_M1_1435435046_1200.mat
     r12379

SRM
Results: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM1/Results/allDampRegressCompare_H1SUSSRM_M1_NoiseComparison_1435348334vs1435435046-1200.pdf
      r12378
Data: /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM1/Data/dampRegress_H1SRM_M1_1435435046_1200.mat
    /ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/SAGM1/Data/dampRegress_H1SRM_M1_1435348334_1200.mat
    r12377

SR3
Results: /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/SAGM1/Results/allDampRegressCompare_H1SUSSR3_M1_NoiseComparison_1435348334vs1435435046-1200.pdf
      r12382
Data: /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/SAGM1/Data/dampRegress_H1SR3_M1_1435348334_1200.mat
    /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/SAGM1/Data/dampRegress_H1SR3_M1_1435435046_1200.mat
    r12381

Jennie W, Sheila, Ryan C, Ibrahim, Corey

Over the last 3 weeks three DARM offstep measurements (where we change the DARM offset to look at the fraction of the light from the differential mode which makes it past the OMC) have been taken.

This is so we can get data points to compare to my model of ARM to OMC mode-matching. These were done at three different CO2 X power levels.

Measurement 1: 2025/06/18 20:44:55 UTC

CO2 central heating on ITMX: 1.698W

CO2 central heating on ITMY: 1.694 W

The test is run with /ligo/gitcommon/labutils/darm_offset_step/auto_darm_offset.py . The data is processed with plot_darm_optical_gain_vs_dcpd_sum.py .

Graphs of the power after the OMC vs. optical gain are in the first plot,  optical gain vs. offset and anti-symmetric port power vs. power out of the omc are in this document.

The average contrast defect is 1.07 mW, the junk light is 679 mW, the transmission of the differential mode light at the AS port by the OMC is 1/1.217 = 82.2%.

Measurement 2: 2025/06/20 15:11:46 UTC

CO2 central heating on ITMX: 1.698 W

CO2 central heating on ITMY: 1.711 W

The test is run with /ligo/gitcommon/labutils/darm_offset_step/auto_darm_offset.py . The data is processed with plot_darm_optical_gain_vs_dcpd_sum.py .

Graphs of the power after the OMC vs. optical gain are in the first plot,  optical gain vs. offset and anti-symmetric port power vs. power out of the omc are in this document.

The avergae contrast defect is 1.03 mW, the junk light is 677 mW, the transmission of the differential mode light at the AS port by the OMC is 1/1.212= 82.5%.

Measurement 3: 2025/06/30 15:06:50 UTC

CO2 central heating on ITMX: 1.698 W

CO2 central heating on ITMY: 1.721 W

The test is run with /ligo/gitcommon/labutils/darm_offset_step/auto_darm_offset.py . The data is processed with plot_darm_optical_gain_vs_dcpd_sum.py .

Graphs of the power after the OMC vs. optical gain are in the first plot,  optical gain vs. offset and anti-symmetric port power vs. power out of the omc are in this document.

The avergae contrast defect is 1.09 mW, the junk light is 694 mW, the transmission of the differential mode light at the AS port by the OMC is 1/1.212= 82.5%.

This is not a very good test for our purposes as I think we want a larger change in mode-matching from thermal tuning to inform our simulations of Arm->OMC mode-mis-match.

Each time we have stepped the CO2Y down (all these darm offset measurements were meant to be repeated after decreasing the CO2 power) for this test (measurement 2 on the 20th June, alog 85238 shows attempt from 23rd June, alog 85335 shows attempt from the 25th June, alog 85429 is measurement 3) we have lost lock, so we might not be able to repeat this measurement with a larger CO2 step.

Jennie W, Sheila, Elenna

In order to get data for mode-matching and for Elenna to get data to calibrate sideband heights we ran some mode scans after the SR3 heater was turned on last night.

16:55:24 UTC Carried out single bounce OMC scan at 10W PSL input with sensor correction on HAM6 on, high voltage on for PZT driver in HAM6, sidebands off , SRM mis-aligned, ITMY mis-aligned, DC 3 and 4 on, OMC ASC on.

Excitation freq changed to 0.005 Hz as the top peak of the TM00 mode looked squint so could have been saturating. Lowering this frequency prevented this.

Ref 15-17 corresponds to dcpd data, pzt exc signal, pzt2 dc monitor.

Then mis-aligned ITMX and aligned ITMY (Sheila had to re-align SR2 to centre on ASC-AS_C).

Measurement starts at 17:08:18 UTC.

Ref 18-20 corresponds to dcpd data, pzt exc signal, pzt2 dc monitor.

Traces saved in 20250516_OMC_scan.xml. The top left plot is the first scan bouncing beam off ITMX, the second scan is the bottom right bouncing off ITMY.

The top right is the two plots of the PZT2 DC voltage monitor. That is, the current voltage applied to the PZT. The bottom left is the plot of the voltage ramp applied to the PZT2 on the OMC for this measurement.

The ndscope attached shows the power in mA transmitted through the OMC on the top, then the PZT used for the scan DC voltage underneath, then the input PZT voltage underneath that, then the reflected power from the OMC in mW, then at the bottom the SR3 heater element temperature in degrees.

Elenna did two more scans in single bounce with sidebands back on and different modulations depths in each.