Looked at this with Michael and Shoshana and the BRS is damped down now. Still not sure what is wrong but we have a theory that one side of the capacitive damper is not actuating. This seems to work okay when the velocities are either low or very high, but if they are moderate the high gain damping doesn't work well enough to get the BRS below a certain threshold, and instead keeps the BRS moderately rung up. We adjusted the damping on/off thresholds so the high gain damping will turn off at a higher velocities.

I will try to do some tests with it next week to see if we can tell if one side of the damper is working better than the other. For now, we should be able to bring the BRS back in loop.

Looking at the high 2ndary microseism it seems to be from the storm off west coast with wave swells of 10m and a swell period of 7.6sec ( ~0.13Hz). Something weird is that the MY seismometer had a big sudden jump in motion at ~23:10 UTC.

Here is a scope showing the LSC loop ring up. The ring up started about 10s before lockloss which coincides with a few gains and filter changes in the LSC loops.

Here's the characterization data and fit results for S1100148, assigned to MC1 M2's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100148_MC1_M2_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100148_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100135, assigned to MC1 M3's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100135_MC1_M3_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100135_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100106, assigned to MC3 M2's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100106_MC3_M2_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100106_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100093, assigned to MC3 M3's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100093_MC3_M3_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100093_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1000274, assigned to PR3 M2's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1000274_PR3_M2_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1000274_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1000277, assigned to PR3 M3's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1000277_PR3_M3_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1000277_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100169, assigned to MC2 M2's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100169_MC2_M2_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100169_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100174, assigned to MC2 M3's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100174_MC2_M3_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100174_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100146, assigned to SR3 M2's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100146_SR3_M2_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100146_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

Here's the characterization data and fit results for S1100134, assigned to SR3 M3's ULLLURLR OSEMs.

This sat amp is a UK 4CH sat amp, D0900900 / D0901284. The data was taken per methods described in T080062-v3, using the diagrammatic setup shown on PAGE 1 of the Measurement Diagrams from LHO:86807.

The data was processed and fit using ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Scripts/
plotresponse_S1100134_SR3_M3_ULLLURLR_20251020.m

Explicitly, the fit to the whitening stage zero and pole, the transimpedance feedback resistor, and foton design string are:

The attached plot and machine readable .txt file version of the above table are also found in ${SusSVN}/trunk/electronicstesting/lho_electronics_testing/satamp/ECR_E2400330/Results/
2025-10-20_UKSatAmp_S1100134_D0901284-v5_fitresults.txt

Per usual, R_TIA_kOhm is not used in the compensation filter -- but after ruling out an adjustment in the zero frequency (by zeroing the phase residual at the lowest few frequency points), Jeff nudged the transimpedance a bit to get the magnitude scale within the ~0.25%, shown in the attached results. Any scaling like this will be accounted for instead with the absolute calibration step, i.e. Side Quest 4 from G2501621, a la what was done for PR3 and SR3 top masses in LHO:86222 and LHO:84531 respectively.

WP12849 Marc is replacing the old PowerTen DC power supply at EX. This supplies the Beckhoff vacuum controls for h0veex. It also supplies the Beckhoff HEPI Pump Controller chassis.

EDC lost 1197 channels when power supply was off (VAC and HPI_PUMPCTRL)

Vac is now back and burt restored at 11:10, we are working on getting the HEPI pump controller back.

Power supply was replaced with Sorensen DCS33-33E supply.  Everything powered back up eventually, minor issues with the HEPI controller were solved.  This completes WP12849

F. Clara, R. McCarthy, G. Moreno, M. Pirello

HEPI controller did not come back on its own. This computer doesn't seem to be set up to start TwinCAT and tcioc automatically. Started both processes manually, but run into an issue that the TwinCAT system was running, but the PLC code was not. After recompiling the PLC code and loading it, the system finally came up.

I plotted the loss between the antisymmetric port (calibrated into the power entering HAM6) to the power on the DCPDs. This is the inverse of the slopes in the graphs above.

All three are poltted on one graph, using plot_AS_vs_DCPD_changes.py in my own cope of the labutils repository at /ligo/home/jennifer.wright/git/local_git_copies/labutils/darm_offset_step/ .

Sheila and Camilla both agreed the loss for the two bottom lines (purple and red) are too high. These imply that a hot OM2 gives us over 20 % output losses.

If we look at the increase in loss from cold OM2 to hot OM2 this is a factor of 2.1 (210 % increase).

Compared to the decrease in optical gain squared (which we expect to reflect the change in output losses, which was:

(0.986^2 - 0.994 ^2) / 0.994^2 = -0.016 (1.6 % decrease).

We might have to check the alignment of out optics was not changing while we changed the darm offset.

Looking at OM1, OM2 and SRM alignment it did change during the darm offset steps with the biggest change (in the third offsset step measurement) being in OM2 pitch and yaw, this is only a change around 6 microradians (Elenna and Jeff state this calibration in correct to within an order of magnitude). Not sure if this enough to invalidate the loss values we measure. OM3 and OMC sus did not change much but this is because IU purposely unlocked the OMC ASC while changing the darm offset.

Jennie W, Matt T,

I plotted the antisymmetric power during the darm offset step vs. the power reflected by the OMC and am now very confused as the AS power looks to be smaller than the power reflected form the OMC. See the ndscope where I have zoomed in on the same time segment for both channels. The OMC-REFL channel is mean to be calibrated into mW and the ASC-AS_C channel is meant to be calibrated into W entering HAM 6 (even though the actual pick-off is the transmission through OM1).

The two plots attached show how the ratio between AS and OMC-REFL power changes during one of the DARM offset measurements we did right after I took this ndscope data.

Plot 1 hr 25 mins into lock.

Plot 2 hrs 59 mins into lock.

For each point the code returns the median of the time series at each step, this mioght be less valie for OMC-REFL as it is a lot noisier than ASC-AS_C.

I am still confused about the hogher power at OMC-REFL and wondering if:

a) I am confused about the calibration of one of these channels.

b) the calibration of one of these channels is wrong.