Thu Oct 23 10:08:16 2025 INFO: Fill completed in 8min 13secs
Gerardo confirmed a good fill curbside.
Attached is comparison of the LSC FF drives before the HAM1 vent (reference traces) and today (live traces). The first time we noticed the roll mode ringing was around June 11, one of the first days we were back into observing after the HAM1 vent (84982).
It doesn't look like there is significantly any difference in the drive between 10-20 Hz for any of the feedforwards. I have already previously checked the filters for high Q features around 13 Hz that might drive the roll mode and there are none. Sheila previously noticed that the roll mode started to ring up after the SRCL and PRCL feedforwards were engaged (87690).
We did a comparison of the FF drives before and after Tuesday, posting here for reference:
The first three are from two days ago with overall MICH FF gain =2, the last three are from earlier today with MICH FF gain =4.
The forst three are from NLN, the second three from low noise length control this morning when we had the MICH FF on.
Following up on [LHO: 87659], we found an error on the file that transfers the SR3/PR3 OSEM estimator fits posted in [LHO: 87612 LHO: 87593] into foton. Maybe this error explains the 0.67 Hz ringing that we had with the estimator ON.
The make_PR3_estimator_LP.m file was jamming the ISI fits into the M1 drive model. This was a copy-paste type error that I have resolved by now. The corrected code was committed to the SVN under revision 12752.
Next update I will make these pieces of code that commission the estimator less hardcoded to hopefully avoid repeating this mistake in the future.
These filters have been updated in both PR3 and SR3. The estimator is still off though!
There seem to maybe be lines in DARM that I don't recall from the past, so we're looking in to a few of those.
The line at 843 Hz seems to be created in the calibration process, since it is present in GDS-CALIB_STRAIN, but not present in CAL-DELTAL_EXTERNAL. Probably not a problem (unless it's there in NLN), but worth noting that it is *not* related to locking problems, since it's not in the raw DARM data.
Jenne asked me to check a line around 27 Hz, this does show up in max power (today see brown trace) but also was there in max power before maintenance Tuesday this week (pink trace).
It doesn't seem to really show up in the NLN state (red trace is before maintenance, blue is one of our locks from early this morning).
My conclusion from Jennie's plot is that that 27 Hz mode isn't a major cause for concern; it's not something new that's giving us trouble.
TITLE: 10/23 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 6mph Gusts, 5mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.39 μm/s
QUICK SUMMARY:
IFO was in IDLE when I got in due to issues last night with a high EY Roll mode. I just started an initial alignment so we can be further along in locking once commissioners arrive onsite.
Locking attempt 1 this morning: Locked to full power, Oli ran the asc high bandwidth script (userapps/isi/h1/scripts/revert_asc.py) premptively to avoid having problems with the 1 Hz ring up.
The last thing this script does is sets the LSC FF gains to 0, 45 seconds after this finished we had a sudden large increase in noise first at 300 Hz in DARM (ETMX ESD) and DHARD then 0.1 second later in CHARD, which unlocked the IFO. This happened in the close beam diverters state, but is probably not related to the beam diverters. This is a different problem than what we've been seeing overnight.
No gains or anything else in the CHARD or DHARD filter banks were changed in those 45 seconds either, which rules out some other rogue change
Elenna and I commented out the DHARD boost from low noise ASC, because it takes 45 degrees of phase at 1Hz and so leaving it off may help our improve our 1Hz problems. This boost was added to improve the stationarity of SRCL to DARM coupling by reducing the DAHRD RMS 77857. We are leaving it off for now because we can probably go to observing without it if we can stay locked.
Next locking attempt we sat for over an hour at full power, without doing the LOWNOISE ASC step.
We had ETMY saturations when we ran through the ESD transitions, and they continued after DARM was switched, until Elenna turned off LSC FF. When we turned the feedforward back on ETMY didn't start saturating. However, at the time that the PRCL and SRCL feedforward came on, the roll mode started ringing up. We lost lock a few minutes into this ring up, but the amplitude was much smaller than the locklosses from this mode overnight (about a factor of 100 lower).
We aren't sure if the roll mode was the cause of the lockloss or not.
Got called at 10:57PM (PT) and IFO was actually locked in NLN with one SDF Diff, which I accepted and is screenshot is below (IMC_DOF_1_P TRAMP from 0 to 3 and IMC_DOF_2_Y TRAMP from 0 to 3).
Good timing for this since the 1Hz ringup was happening. I saw earlier today that turning on the ASC High Gain might help with this so I turned it on and it seems to be working.
SQZ also looked terrible inthe high-frequency domain. I ran the OPO temp scan and the SQZ Angle, but this did not seem to improve anything (plot attached).
Additionally, the EY Roll Ringup that plagued Ryan C's EVE shift is indeed happening again. I'm unsure what to do about this since it seems he and Rahul tried a multitude of damping techniques without avail.
ASC High Gain was turned off ~5 minutes after it seemed to be working. A minute later, we it rang up again and we lost lock.
So there's two issues (or maybe they're related I don't know):
1. 1Hz Ringup that can be survived while locked but only in High Gain settings
2. ETMY Roll mode which just rings up consistently
Out of ideas - will continue to investigate but nothing seems to be helping.
Called Rahul for help with the EY Roll Mode
The plan:
The issue with this plan is that it seems that without the high gain on, the oscillation prompts a lockloss but we'll see what happens as I watch it closely this time.
Lost lock at OMC_WHITENING after spending ~10-15 minutes at each powerup state to ensure EY Roll mode and Violins were low. They were. The 1Hz ringup started on queue as soon as LOWNOISE_ASC turned on and got worse. I think I turned on the ASC High Gain too early - confused as to what caused this lockloss. Trying again. It seems that the slow method works to avoid the EY Roll Mode ringup.
Additionally, Elenna's alog 87658 talks of her plan for how to try to avoid the 1Hz ringup and it involves DHARD_P to HBW using turning off FM8, then FM4. I will do this instead of the entire HBW ASC EQ script.
Lockloss tool sees EY glitching 1.2 before lockloss.
After some DRMI troubles, finally back to where I was before. In about 10 minutes, EY Roll Mode permitting, I will attempt to go to NLN and watch the 1Hz ringup, turning on HBW DHARD_P when I see the ringup.
It worked! (for now). We're in NLN with bad SQZ though similar range to last time we were locked (which isn't that good). The EY Roll Mode is on the rise though and if this lock is like the ones Ryan C (EVE) had, then usually they rise until lockloss in ~45 mins to an hour. I'm going to give IFO at least 10 minutes before re-engaging the DHARD_P LBW. The ringup comes back thereafter according to my last lock and Ryan's too. So, let's see what happens.
Really doesn't look great especially that as soon as we're near NLN, the EY Roll mode begins to trend upwards. Violin modes are going down though.
Well... The mode has rung up again after switching FM4 and FM8 back on... I don't know what to do here. Meanwhile EY Roll Mode is still ringing up despite locking veeery slowly per Rahul's advice.
EY Mode 15 is rung up slightly and damping it per the settings has made things worse - resetting its gain to 0 seems to calm it down.
My not-very-creative-out-of-options plan now is to wait here in these settings and attempt to go back to LBW DHARD P in another 20/30 or so... However, by then we will probably have lost lock due to Roll EY ::(
As expected when I went back to LBW, DHARD P rung up again so that doesn't work either.
While violins are high, they've been much higher before so we're not really ringing them up - they're all reporting as damping now anyway.
OMC DCPDs are going quite wild I assume due to this Roll Mode (attached).
If we lose lock here, I'm just going to IDLE IFO due to inability to stay locked and to avoid any more violin mode ringup. On the bright side, it's nearing DAY shift, involving well-rested experts.
Lockloss 11:51 UTC - IFO in IDLE.
TITLE: 10/23 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: We made it to NLN but the ETMY roll mode took us down, it appears to have rung up each time we get into OMC_WHITENING since maintenance.
I found new settings for ITMX mode13, FM1+FM2+FM10 G= -0.5.
The first 2 aquisitions we saw the Roll mode ringup but this 3rd time we did not, we slowly brought the IFO up, pausing to look at the mode in CHECK_VIOLINS, 10Ws, 25Ws, MAX_POWER, TRANSITION_FROM_ETMX, and LOWNOISE_ESD_ETMX.
LOG: No log.
18:45 UTC While Jim was running a measurement on ISI HAM5, SUS ITMY started to flash its' red Rocker Switch Death on L2 and report that its' L2 OSEMs were in fault, we also noticed there's a big new line at ~92Hz. Jeff turned off feedback from L2. It looks like it could be a sat amp issue, the L2 sat amp was upgraded this past Tuesday alog87469. Jeff is starting to work on characterizing a sat amp box in the EE shop to swap in.
We would need a lockloss to swap this component.
We are going to try to go back into Observing for a bit until we can fix it or lose lock.
19:31 UTC Observing
FYI -- we went into observing with the ITMY PUM sat amp OSEM PD's still dead. We turned OFF the ITMY L2 (PUM) to R0 "damping" feedback loop, so the failed sensors *should* not have any impact on the IFO. However, an obvious, loud ~92-93 Hz feature remained new and glaringly obvious in the DARM sensitivity.
@DetChar / @CW Group Probably best to just veto this observation stretch, unless we -- in the future -- find some amazingly exceptional event.
2025-10-16 19:31 UTC to 19:54 UTC.
ITMY L2 (PUM) Sat Amp S1100148 installed on 10/14/2025. Replaced on 10/16/2024 with S1100080.
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=87469
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:
| Optic | Stage | Serial_Number | Channel_Number | OSEM_Name | Zero_Pole_Hz | R_TIA_kOhm | Foton_Design |
|---|---|---|---|---|---|---|---|
| ITMY | L2 | S1100148 | CH1 | UL | 0.095:5.19 | 120.5 | zpk([5.19],[0.095],1,"n") |
| CH2 | LL | 0.0957:5.24 | 120.0 | zpk([5.24],[0.0957],1,"n") | |||
| CH3 | UR | 0.0958:5.24 | 120.125 | zpk([5.24],[0.0958],1,"n") | |||
| CH4 | LR | 0.0967:5.28 | 120.375 | zpk([5.28],[0.0967],1,"n") |
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:
| Optic | Stage | Serial_Number | Channel_Number | OSEM_Name | Zero_Pole_Hz | R_TIA_kOhm | Foton_Design |
|---|---|---|---|---|---|---|---|
| ETMX | L2 | S1100119 | CH1 | UL | 0.0949:5.19 | 120 | zpk([5.19],[0.0949],1,"n") |
| CH2 | LL | 0.0971:5.32 | 120 | zpk([5.32],[0.0971],1,"n") | |||
| CH3 | UR | 0.0964:5.27 | 120 | zpk([5.27],[0.0964],1,"n") | |||
| CH4 | LR | 0.0957:5.23 | 120 | zpk([5.23],[0.0957],1,"n") |
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:
| Optic | Stage | Serial_Number | Channel_Number | OSEM_Name | Zero_Pole_Hz | R_TIA_kOhm | Foton_Design |
|---|---|---|---|---|---|---|---|
| ITMX | L2 | S1100118 | CH1 | UL | 0.0966:5.27 | 120 | zpk([5.27],[0.0966],1,"n") |
| CH2 | LL | 0.0961:5.25 | 120 | zpk([5.25],[0.0961],1,"n") | |||
| CH3 | UR | 0.0963:5.26 | 120 | zpk([5.26],[0.0963],1,"n") | |||
| CH4 | LR | 0.097:5.3 | 120 | zpk([5.3],[0.097],1,"n") |
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:
| Optic | Stage | Serial_Number | Channel_Number | OSEM_Name | Zero_Pole_Hz | R_TIA_kOhm | Foton_Design |
|---|---|---|---|---|---|---|---|
| ETMY | L2 | S1100127 | CH1 | UL | 0.0963:5.26 | 121.25 | zpk([5.26],[0.0963],1,"n") |
| CH2 | LL | 0.0958:5.24 | 121.25 | zpk([5.24],[0.0958],1,"n") | |||
| CH3 | UR | 0.0952:5.2 | 121.25 | zpk([5.2],[0.0952],1,"n") | |||
| CH4 | LR | 0.0954:5.21 | 121.25 | zpk([5.21],[0.0954],1,"n") |
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.
ITMY L2 (PUM) Sat Amp S1100148 installed on 10/14/2025. Replaced on 10/16/2024 with S1100080.
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=87515
