filiberto.clara@LIGO.ORG - posted 13:11, Tuesday 14 October 2025 - last comment - 17:22, Tuesday 14 October 2025(87469)
Sat Amps Modified: L2 (PUM) Stages for ETMX, ETMY, ITMX, and ITMY
WP 12836
ECR E2400330
Modified List T2500232
The following SUS SAT Amps were upgraded per ECR E2400330. Modification improves the whitening stage to reduce ADC noise from 0.05 to 10 Hz.
| Suspension | Old | New | OSEM |
| ETMX L2 (PUM) | S1100146 | S1100119 | ULLLURLR |
| ETMY L2 (PUM) | S1100137 | S1100127 | ULLLURLR |
| ITMX L2 (PUM) | S1100135 | S1100118 | ULLLURLR |
| ITMY L2 (PUM) | S1000277 | S1100148 | ULLLURLR |
F. Clara, J. Kissel, O. Patane
Here's the characterization data and fit results for S1100148, assigned to ITMY L2'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_ITMY_L2_ULLLURLR_20250917.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/
2025-09-17_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 S1100119, assigned to ETMX L2'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_S1100119_ETMX_L2_ULLLURLR_20250916.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/
2025-09-16_UKSatAmp_S1100119_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 S1100118, assigned to ITMX L2'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_S1100118_ITMX_L2_ULLLURLR_20250916.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/
2025-10-14_UKSatAmp_S1100118_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 S1100127, assigned to ETMY L2'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_S1100127_ETMY_L2_ULLLURLR_20250916.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/
2025-09-16_UKSatAmp_S1100127_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.