aLIGO LHO Logbook

H1 CDS - Power glitch 17:25:25 Thu 23 Oct 2025 PDT

david.barker@ligo.org — Fri, 24 Oct 2025 07:53:13 -0700

Author: david.barker@ligo.org

Report ID: 87711

We had a small mains power glitch 17:25:25 Thu 23 Oct 2025 PDT. It was only reported by the OSB GC UPS.

Images attached to this report

LHO General - Ops Day Shift Start

ryan.short@ligo.org — Fri, 24 Oct 2025 07:34:21 -0700

Author: ryan.short@ligo.org

Report ID: 87710

TITLE: 10/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 8mph Gusts, 6mph 3min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.62 μm/s
QUICK SUMMARY: H1 was down overnight due to ongoing locking issues. I'll start by running through an initial alignment while I get caught up on events of the past couple days.

Wind low, microseism steady around 90th percentile
DR1 dust monitor reports no change in counts
All other systems nominal

H1 General - OPS Thursday EVE shift summary

ryan.crouch@ligo.org — Thu, 23 Oct 2025 22:01:16 -0700

Author: ryan.crouch@ligo.org

Report ID: 87708

TITLE: 10/24 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: ~~Tony~~
SHIFT SUMMARY: Microseism is still slowly trending up, I got up past MAX_POWER twice, I confirmed the Roll mode damping works at 62Ws.
LOG: No log.

Lock^#1

We sat in ADJ_POWER for a little over an hour at 50Ws as Rahul damped the Roll mode. It seems to be on ETMX. We manual-ed to LOWNOISE_COIL_DRIVERS and later up to LOWNOISE_LENGTH_CONTROL and ETMY started to saturate (it looked to be coming from SUSETMY DAC 1, channels 1, 2, 3. We noticed that the DCPDs were growing as well and PIMON was showing some red. We then went back to ADJ_POWER and lowered the power down to 45Ws, the saturations stopped but the PI kept growing till we lost lock. Lowering the power looks to have made the PI ringup even faster?
I set the gain of the ETMY roll mode to zero in ISC_LOCK and reloaded it. The Thermalization GRD went into error as we went into LOWNOISE_LENGTH_CONTROL since the SRCL1 offset was not at the nominal, I set the nominal back and reloaded it and it did not fix the error.

Lock^#2

02:42 UTC IA
03:48 UTC I got back to ADJ_POWER and brought us down from 62 to 40W
04:17 UTC Shortly after I brought us back up to 62 at Sheilas' suggestion and tried Rahuls new Roll mode damping settings and they seemed to work at MAX_POWER, after 6 or 7 minutes we tried to go to LOWNOISE_LENGTH_CONTROL. We lost lock shortly after during TRANSITION_FROM_ETMX. Sheila accepted the filter changes for the new Roll mode settings.
04:41 UTC Holding in DOWN

Images attached to this report

H1 SUS - Modified the script to get the OSEM estimators installed on PR3/SR3

edgard.bonilla@ligo.org — Thu, 23 Oct 2025 21:15:29 -0700

Author: edgard.bonilla@ligo.org

Report ID: 87709

I modified Oli's script make_EST_model.m that gets the OSEM estimator filters into the front-end models. This script is now the preferred way to get any estimator model filters into the real-time computers. The change was made to add failsafes to avoid further errors on the translation of fitted filters into foton ( see LHO: 87689 ).

For the script to work, any .mat files with estimator filters must have the following syntax:

(sus)_est_model.(dof).(input_stages).(inputdof2dof) - For example

PR3_est_model.P.suspoint.L2P contains the zpk for the PR3 suspoint L to M1 OSEM P model.

The format for the filters can be seen in any of the .mat files listed below that live in (svnroot)/sus/trunk/HLTS/Common/FilterDesign/Estimator/. The files come with a README that indicates at how the fits inside were created

est_model_H1PR3_L_2025-10-07.mat -- contains slightly tweaked versions of the PR3 L (and P) models reported in [LHO: 87593]
est_model_H1PR3_P_2025-10-07.mat -- contains slightly tweaked versions of the PR3 P (and L) models reported in [LHO: 87593]
est_model_H1PR3_Y_2025-08-19.mat -- contains the PR3 Y fits from [LHO: 86563]

est_model_H1SR3_L_2025-10-07.mat -- contains slightly tweaked versions of the SR3 L (and P) models reported in [LHO: 87612]
est_model_H1SR3_P_2025-10-07.mat -- contains slightly tweaked versions of the SR3 P (and L) models reported in [LHO: 87612]
est_model_H1SR3_Y_2025-08-05.mat -- contains the cleaned SR3 Y fits from [LHO: 86366]

These are the new .mat files that have the current OSEM estimator models. Until further notice, all previously existing .mat and .m files for OSEM estimator models/fits have been deprecated. We will later talk with Oli to standardize the addition of the OSEM estimator blends.

The updated make_EST_model.m, as well as the rest of the .mat files with the new syntax have been updated to the SUS svn under revision 12754.

SUS

H1 SUS - Comment to Maybe the roll mode isn't ETMY after all?

rahul.kumar@ligo.org — Thu, 23 Oct 2025 18:18:31 -0700

Author: rahul.kumar@ligo.org

Report ID: 87707

I am able to ring up 13.75 Hz by actuating on ETMX roll - see attached plot.

I was able to ring up this mode and then damp it down using the following settings - FM2+FM3+FM4, Gain -200 (-60 deg phase filter) for ETMX @53W input power. This needs to be checked at higher power and at NLN.

Images attached to this report

H1 SUS - Comment to Maybe the roll mode isn't ETMY after all?

jenne.driggers@ligo.org — Thu, 23 Oct 2025 16:47:24 -0700

Author: jenne.driggers@ligo.org

Report ID: 87706

Rahul is working to identify which optic this problematic 13.75 Hz mode is, and so has been actuating on ITMY. We're now seeing a mode at 13.87 Hz with the ITMY actuation, so I think ITMY is absolved from being the problematic optic.

Attached plot is during ITMY actuation.

Images attached to this report

H1 SUS - Comment to SR3/PR3 estimator filter error

oli.patane@ligo.org — Thu, 23 Oct 2025 16:42:35 -0700

Author: oli.patane@ligo.org

Report ID: 87705

These filters have been updated in both PR3 and SR3. The estimator is still off though!

Images attached to this report

H1 General - Ops Day Shift End

oli.patane@ligo.org — Thu, 23 Oct 2025 16:41:22 -0700

Author: oli.patane@ligo.org

Report ID: 87704

TITLE: 10/23 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Multiple locklosses today while continuing to troubleshoot the ifo. Multiple initial alignments were ran (it seems like we're needing them more often the past few days). Locking attempts and locklosses are documented in 87679 and 87701. There are multiple issues so it's been hard trying to distinguish them from each other and investigate one at a time. Secondary microseism has been heading back up too unfortunately.
LOG:

14:30UTC Started trying to relock
- Ran initial alignment
- Various locklosses

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:52	FAC	Randy	YARM	n	Sealing the tube	21:57
15:32		Richard, Ken	MX, MY	n	Checking out emergency pump	16:03
16:28	FAC	Kim	EX, MX	n	Putting down rain mats	16:56
16:44	FAC	Tyler + contractor	MY	n	Looking at scaffolding	18:44
19:37		Keita	OptLab	y(local)	ISS Array	22:26
20:09	PCAL	Tony	PCAL Lab	y(local)	Take equipment in and put on apetures	20:14

H1 General - OPS Thursday EVE shift start

ryan.crouch@ligo.org — Thu, 23 Oct 2025 16:14:09 -0700

Author: ryan.crouch@ligo.org

Report ID: 87703

TITLE: 10/23 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 9mph Gusts, 6mph 3min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.51 μm/s
QUICK SUMMARY:

We're still fighting to stay locked
- Rolls mode and the ASC oscillation are still present
Microseism is increasing back to around the 90th percentile

H1 General - Checking last few locklosses

oli.patane@ligo.org — Thu, 23 Oct 2025 16:00:50 -0700

Author: oli.patane@ligo.org

Report ID: 87701

Looking at the last few locklosses from higher states from today and looking for any similarities:

2025-10-23_15:50:38 UTC (CLOSE_BEAM_DIVERTERS) quads, asc
MAX_POWER to LL: 00:08:30
- DHARD increase right before, DARM oscillation @ 10 Hz

2025-10-23_18:23:42 UTC(LOWNOISE_LENGTH_CONTROL) quads, asc
MAX_POWER to LL: 01:14:00
- DARM oscillation @ 6 Hz

2025-10-23_20:59:21 UTC (LOWNOISE_ESD_ETMX) quads, asc
MAX_POWER to LL: 01:13:00
- DARM oscillation @ 10 Hz

2025-10-23_22:12:25 UTC (TRANSITION_FROM_ETMX) quads, asc -> maybe secondary useism?
MAX_POWER to LL: 00:02:30
- IMC-REFL_SERVO_SPLITMON saturated right before the lockloss (possible cause - can high microseism do this?)

ISC, Lockloss

Images attached to this report

H1 CDS - Comment to Guardian code changes since Monday

david.barker@ligo.org — Thu, 23 Oct 2025 15:21:30 -0700

Author: david.barker@ligo.org

Report ID: 87700

Filter Module changes since Monday.

the following models have had filter module changes since Monday:

h1sus[mc1, mc2, mc3, pr3, sr3]

h1isietm[x, y]

h1asc

The full list of filter differences can be found in /ligo/home/david.barker/tuesdaymaintenance/23oct2025/filter_diffs

H1 SUS - Comment to Maybe the roll mode isn't ETMY after all?

rahul.kumar@ligo.org — Thu, 23 Oct 2025 15:16:21 -0700

Author: rahul.kumar@ligo.org

Report ID: 87699

As per Elenna's suggestion - we will start with damping ITMY roll mode first.

ETMY roll mode gain will be set to zero for the next lock.

H1 SUS - Maybe the roll mode isn't ETMY after all?

jenne.driggers@ligo.org — Thu, 23 Oct 2025 14:51:34 -0700

Author: jenne.driggers@ligo.org

Report ID: 87698

Maybe the roll mode we're fighting today isn't ETMY after all?

In the attached plot, the traces are 20 min apart, and you can see that the mode we were watching at 13.75 Hz gets bigger. Throughout this time, Rahul was changing setttings on SUS-ETMY_M0_DARM_DAMP_R, trying to get it to stop increasing. However, when the output of the damping filter was a very small number of counts, we weren't really seeing big changes in the slope of the increase in the monitor filter H1:SUS-ROLL_ETMY_RMS_LOG10_OUTMON. When Rahul increased the gain to 1200 (from the original of 40), we started ringing up a different mode quite quickly. That other mode is 13.94 Hz.

13.94 Hz doesn't match any of the roll mode monitor filters we have in place (second attachment) according to the names of the filters. But, maybe this means that ETMY is actually at 13.94 Hz, and some other optic is at 13.75 Hz? Back in July (alog 84982 that Elenna pointed me to), we originally thought that 13.7 Hz was ETMX, but had found at that time that actuating ETMY seemed to improve things.

Anyhow, we may also consider trying to actuate on other optics, to see if we can do anything to that 13.75 Hz mode? While the monitor filters are all quite narrow (as they should be), the actuator filters appear to all be the same between the optics.

ISC

Images attached to this report

H1 ISC - Comment to Calibration adding line at ~843 Hz

jenne.driggers@ligo.org — Thu, 23 Oct 2025 14:03:27 -0700

Author: jenne.driggers@ligo.org

Report ID: 87697

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.

H1 CDS - Guardian code changes since Monday

david.barker@ligo.org — Thu, 23 Oct 2025 13:29:52 -0700

Author: david.barker@ligo.org

Report ID: 87696

To help with troubleshooting H1 locking, I have compiled a list of Guardian code changes which have been made since the last robust locking on Monday 20th October 2025.

30 nodes have been reloaded with modifed code since Monday. Note that some of these reloads were to just resync the nodes to the latest lscparams.py and clear the GRD-CFC.

A summary of the nodes is given in the attached txt file.

Full details of the code changes can be found in /ligo/home/david.barker/tuesdaymaintenance/23oct2025/grd_diffs/

Non-image files attached to this report

grd_changes.txt

H1 ISC - Comment to Comparing LSC FF drive before and after vent

jennifer.wright@ligo.org — Thu, 23 Oct 2025 13:09:26 -0700

Author: jennifer.wright@ligo.org

Report ID: 87694

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.

Images attached to this report

H1 AOS - Impulses on ETMY before lockloss last night

jennifer.wright@ligo.org — Thu, 23 Oct 2025 13:06:26 -0700

Author: jennifer.wright@ligo.org

Report ID: 87693

Looking back at this alog #87678 from Ibrahim, I looked at the lockloss tool for this time and could see the 1Hz growing oscillation on DHARD_P but also three impulse/glitchy things on ETMY drive and showing up in DARM1 loop.

Images attached to this report

LHO VE - Thu CP1 Fill

david.barker@ligo.org — Thu, 23 Oct 2025 12:43:01 -0700

Author: david.barker@ligo.org

Report ID: 87692

Thu Oct 23 10:08:16 2025 INFO: Fill completed in 8min 13secs

Gerardo confirmed a good fill curbside.

Images attached to this report

H1 ISC - Comparing LSC FF drive before and after vent

elenna.capote@ligo.org — Thu, 23 Oct 2025 12:42:25 -0700

Author: elenna.capote@ligo.org

Report ID: 87691

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).

Images attached to this report

H1 General - Comment to Ops Day Shift Start

sheila.dwyer@ligo.org — Thu, 23 Oct 2025 12:33:51 -0700

Author: sheila.dwyer@ligo.org

Report ID: 87690

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.

Images attached to this report

H1 SUS - SR3/PR3 estimator filter error

edgard.bonilla@ligo.org — Thu, 23 Oct 2025 12:12:22 -0700

Author: edgard.bonilla@ligo.org

Report ID: 87689

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.

SUS

H1 ISC - Comment to Calibration adding line at ~843 Hz

jennifer.wright@ligo.org — Thu, 23 Oct 2025 12:10:56 -0700

Author: jennifer.wright@ligo.org

Report ID: 87688

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).

Images attached to this report

H1 SUS - Comment to OPS Thursday DAY shift update

filiberto.clara@ligo.org — Thu, 23 Oct 2025 11:29:18 -0700

Author: filiberto.clara@ligo.org

Report ID: 87687

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

H1 SUS - Comment to Sat Amps Modified: L2 (PUM) Stages for ETMX, ETMY, ITMX, and ITMY

filiberto.clara@ligo.org — Thu, 23 Oct 2025 11:26:06 -0700

Author: filiberto.clara@ligo.org

Report ID: 87685

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

H1 ISC - Calibration adding line at ~843 Hz

jenne.driggers@ligo.org — Thu, 23 Oct 2025 10:34:59 -0700

Author: jenne.driggers@ligo.org

Report ID: 87684

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.

CAL

Images attached to this report

H1 General - Comment to Ops Day Shift Start

sheila.dwyer@ligo.org — Thu, 23 Oct 2025 09:56:59 -0700

Author: sheila.dwyer@ligo.org

Report ID: 87683

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.

H1 General - Comment to Ops Day Shift Start

oli.patane@ligo.org — Thu, 23 Oct 2025 09:33:23 -0700

Author: oli.patane@ligo.org

Report ID: 87682

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

Images attached to this report

H1 General - Comment to Ops Day Shift Start

sheila.dwyer@ligo.org — Thu, 23 Oct 2025 09:21:53 -0700

Author: sheila.dwyer@ligo.org

Report ID: 87681

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.

Images attached to this report

H1 General - Ops Day Shift Start

oli.patane@ligo.org — Thu, 23 Oct 2025 07:40:39 -0700

Author: oli.patane@ligo.org

Report ID: 87679

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.

H1 General - Comment to OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Thu, 23 Oct 2025 04:57:43 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87678

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.

Images attached to this report

H1 General - Comment to OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Thu, 23 Oct 2025 04:51:38 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87677

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.

H1 General - Comment to OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Thu, 23 Oct 2025 03:47:14 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87676

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.

H1 General - Comment to OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Thu, 23 Oct 2025 02:13:00 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87675

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.

H1 General - Comment to OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Thu, 23 Oct 2025 02:01:44 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87674

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.

H1 General - Comment to OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Thu, 23 Oct 2025 00:02:01 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87673

Called Rahul for help with the EY Roll Mode

The plan:

Move to NLN very very slowly stopping at every stage of powerup and watching for violins
Once at NLN watch for the 1Hz ringup and activate High Gain settings

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.

H1 General - OPS OWL Shift: SDF Diff, Terrible SQZ, EY Non-damping Roll Mode, 1Hz Oscillation

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 23:50:16 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87672

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.

Images attached to this report

H1 General - OPS Wednesday EVE shift summary

ryan.crouch@ligo.org — Wed, 22 Oct 2025 22:03:01 -0700

Author: ryan.crouch@ligo.org

Report ID: 87660

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.

00:43 UTC We reached OMC_WHITENING
- ETMY roll mode starts to ringup
- 01:35 UTC lockloss from ETM glitch?
02:21 UTC OMC_WHITENING again, we're close to the limit so it shouldn't take very long
- The ETMY roll mode looks to slowly increasing again, I'm going to try to damp it
- 02:39 UTC NLN
  - SQZ looked bad, so I ran SCAN_OPO_TEMP then SCAN_SQZ_ANG, still looked bad after
  - I had some SDFs to accept, mostly offsets (ALSEY & LSC, ISCEY & ASC & ASCIMC, ALSEX & ISCEX & OMC)
  - I never made into Observing as I was fighting the ever ringing up ETMY roll mode until it made us lose lock
    - The 1Hz oscillation also showed up, as soon as I turned FM4 back on the Oscillation returned
03:13 UTC lockloss from ETMY roll mode
- Rahul logged on to take a look with me, we paused at various states
- 04:40 UTC NLN
  - 1Hz showed up, I turned off FM8 waited until it was fully off then FM4, as soon as FM4 is turned off and on the 1Hz seems to appear on DHARD
  - To turn them back on go in reverse, slowly
  - Something is growing, as seen in ASC-INP1 and LSC-PR_GAIN, Its at 1Hz even though I turned off the DHARD_P filters?
  - 04:52 UTC lockloss from the oscillation I'm assuming

SUS

Images attached to this report

H1 General - 03:13 UTC Lockloss

ryan.crouch@ligo.org — Wed, 22 Oct 2025 20:19:37 -0700

Author: ryan.crouch@ligo.org

Report ID: 87671

I had been in NLN for 35 minutes fighting the ETMY roll mode, I also ran some SQZ stuff since it looked terrible (OPO_TEMP_SCAN, then ANG_SCAN) while in NLN. I was unsuccessful in damping the mode and it eventually grew saturated the DCPDs and killed the lock, there was also increased ground motion from a 5.6 from eastern Russia during this. In the middle of fighting the roll mode I saw the 1Hz oscillation start in DHARD_P so I turned off FM8 then FM4 on DHARD_P which fixed it.

Lockloss

H1 SUS - Comment to PR3 and SR3 L and P Estimators turned off for now

brian.lantz@ligo.org — Wed, 22 Oct 2025 20:17:35 -0700

Author: brian.lantz@ligo.org

Report ID: 87670

Thanks for catching this, Oli. I made a note in FRS ticket 35410 reminding us to make an installation script which automatically sets all the epics variables so we are more likely to get all the right settings from the beginning.

H1 ISC - Comment to 0.6 Hz oscillation due to estimator, 1 Hz oscillation still causing lockloss

elenna.capote@ligo.org — Wed, 22 Oct 2025 18:41:24 -0700

Author: elenna.capote@ligo.org

Report ID: 87669

I tried to measure DHARD P to understand what the instability is but we had a lockloss. Looks like it's an ETM glitch?

My recommendation is to put DHARD P in HBW if the 1 Hz starts oscillating again.

H1 General - Comment to OPS Wednesday EVE shift start

ryan.crouch@ligo.org — Wed, 22 Oct 2025 18:23:40 -0700

Author: ryan.crouch@ligo.org

Report ID: 87668

We've also noticed that the ETMY roll mode is ringing up, turning off the damping made it ringup faster.

H1 ISC - Comment to 0.6 Hz oscillation due to estimator, 1 Hz oscillation still causing lockloss

elenna.capote@ligo.org — Wed, 22 Oct 2025 18:20:48 -0700

Author: elenna.capote@ligo.org

Report ID: 87667

I've been flipping back and forth between high and low bandwidth DHARD P. The 1 Hz definitely begins when we are in LBW, and it seems to actually be the lowpass/reshaping in FM4 that is the issue.

I also noticed that there is a glitch in DARM whenever FM4 is turned on or off, so I increased the filter ramp time from 15 to 20 seconds.

To take DHARD P to HBW, disengage FM8, wait for the filter to ramp, then disengage FM4.

To take DHARD P to LBW, engage FM4, wait for the filter to ramp, then engage FM8.

H1 General - Comment to OPS Wednesday EVE shift start

ryan.crouch@ligo.org — Wed, 22 Oct 2025 18:07:21 -0700

Author: ryan.crouch@ligo.org

Report ID: 87666

IX13 has been the problem mode, I've set its' gain to 0 in lscparams and reloaded the VIOLIN node. I think I have found a new setting for IX13, I changed the phase from -60 to-30 and used a negative gain. Its damping, slowly...

SUS

H1 ISC - Comment to 0.6 Hz oscillation due to estimator, 1 Hz oscillation still causing lockloss

elenna.capote@ligo.org — Wed, 22 Oct 2025 17:52:58 -0700

Author: elenna.capote@ligo.org

Report ID: 87665

I held us at high bandwidth ASC for 9 minutes and there was no 1 Hz oscillation. A few minutes after running lownoise ASC the 1 Hz oscillation came back. It begins first in DHARD P. I stopped the oscillation by running the ASC HI GAIN script that we set up for earthquakes. It looks like the oscillation stopped as soon as DHARD P was put into HBW state. After waiting a few minutes, I put us back into the lownoise state. I have previously been suspicious of DHARD P for being the culprit causing the 1 Hz ring up. My recommendation is that if we see this again, try turning OFF FM8 in the DHARD P filter module (labelled GVBoost). If that doesn't work, just run the HI GAIN ASC script like you would for an earthquake, on the IS sensor config screen.

EDIT: I posted this comment too soon- the 1 Hz ringing came back. I tried just turning off DHARD P FM8, but that did nothing. However, going to Hi Gain ASC worked again, so that seems to be a good way to get around this (for now).

H1 General - Comment to OPS Wednesday EVE shift start

ryan.crouch@ligo.org — Wed, 22 Oct 2025 17:52:45 -0700

Author: ryan.crouch@ligo.org

Report ID: 87664

00:43 UTC We reached OMC_WHITENING where we will sit to damp violins for a bit.

H1 SUS - PR3 and SR3 L and P Estimators turned off for now

oli.patane@ligo.org — Wed, 22 Oct 2025 17:24:37 -0700

Author: oli.patane@ligo.org

Report ID: 87659

Turns out that I had forgotten to turn the input on for the PR3 P estimator contribution from L (H1:SUS-PR3_M1_EST_P_FUSION_MODL_DRV_L_2GAP) (thanks to Edgard and Brian for having us even consider the estimators!), and that was causing the 0.6 Hz ASC ringups (87658). Even though we're pretty sure we found the cause, we've decided to temporarily turn off the PR3 and SR3 L and P estimators until we're back up and can verify that they are now working correctly.

SEI

Images attached to this report

H1 General - Ops Day Shift End

oli.patane@ligo.org — Wed, 22 Oct 2025 17:21:40 -0700

Author: oli.patane@ligo.org

Report ID: 87663

TITLE: 10/23 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Currently relocking and at LOWNOISE_COIL_DRIVERS. Still struggling with a 1 Hz oscillation(87658), but we've solved issues with MICH phase margin and with a 0.6 Hz oscillation caused by incorrect estimator settings, so 2/3 of the issues solved?
LOG:

14:30UTC Started relocking
   Initial alignment
   Lockloss from OMC_WHITENING due to 1 Hz ringup
   Multiple locklosses from DRMI and under due to ALSX getting noisy and ALSY having some glitchy drops in power
   Locklosses from LOWNOISE_LENGTH_CONTROL, MOVE_SPOTS, etc.

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:45		Matt	JOAT	n	Putting stuff away	15:50
15:49	FAC	Kim	OptLab	n	Tech clean	16:10
16:48	FAC	Randy	XTube	n	Caulking more tube	20:40
17:26		Tony	CER	n	Putting laptop away	17:31
20:18	VAC	Travis	MX, MY	n	Taking measurements	23:43
20:18		Keita	OptLab	y(local)	ISS Array	21:44
20:39	FAC	Randy	Yarm	n	More Caulking of the BTE, starting at EY	22:08
20:40	IO	Rahul	Opt Lab	y(local)	ISS array	21:44
20:58	SEI/CC	Jim, Mitch	Ends	n	Wind fence, HEPI, and dust mon pump FAMISs	00:27
21:17		Tyler, Shinji	OptLab	y(local)	Meeting with Keita	21:44
21:47		Jenne, +PAC	Roof	n	Overlooking the arms	22:08
22:38	PCAL	Tony	PCAL Lab	y(local)	Setting up measurement	22:38

H1 ISC - Comment to 0.6 Hz oscillation due to estimator, 1 Hz oscillation still causing lockloss

elenna.capote@ligo.org — Wed, 22 Oct 2025 17:19:42 -0700

Author: elenna.capote@ligo.org

Report ID: 87662

We have been thinking that maybe the MICH UGF is too low (I had a memory that it was supposed to be 8 Hz). Then I found this alog from Evan where he designed it to be 5.5 Hz and the phase margin looks about the same 76631. Note that Oli's measurement was taken after we DOUBLED the gain, so somewhere along the way we lost 6 dB of gain.

H1 ISC - Comment to 0.6 Hz oscillation due to estimator, 1 Hz oscillation still causing lockloss

oli.patane@ligo.org — Wed, 22 Oct 2025 17:18:19 -0700

Author: oli.patane@ligo.org

Report ID: 87661

Here's the measurements taken for MICH that show the phase margins at different points in the locking sequence

Images attached to this report

H1 ISC - 0.6 Hz oscillation due to estimator, 1 Hz oscillation still causing lockloss

elenna.capote@ligo.org — Wed, 22 Oct 2025 16:48:44 -0700

Author: elenna.capote@ligo.org

Report ID: 87658

We managed to track down the source of the 0.6 Hz oscillation that we see at move spots and full power. It seems to be the result of the new pitch and length estimators on PR3 and SR3 that were installed on Tuesday. We tested this by sitting at move spots (after the spots converged), and turning on and off the estimators for a few minutes at a time. When turning ON the estimators, the 0.6 Hz ringing is not immediately apparent- it will slowly grow. However, once the 0.6 Hz oscillation is visible in the controls, turning OFF the estimator immediately stops the ringing. Therefore, we think this is the culprit for this instability. Oli will be turning off the length and pitch estimators for PR3 and SR3 for now. The yaw estimators are still on because they have been operating stably for a long time and were not changed this Tuesday.

We have also put the factor of 2 increase of MICH2 gain into the guardian, since we kept forgetting to add it in. Several locklosses that we thought were due to various other things were actually due to the MICH loop ringing up.

Finally, we just had a lockloss after moving to camera servos because the 1 Hz oscillation began to grow. Here is everything I tried to stop the ringing (none of it worked):

CSOFT P gain was already at 30. I dropped it to 25 and re-increased to 30 several times, no change either way
INP1 P gain was at -1, I doubled it and then tripled it, no change
INP1 Y gain was at -0.1, doubled it, no change
DSOFT P gain was at 5, I increased to 10, then 15, no change
DSOFT Y gain was at 5, increased to 10, no change

I then had an idea to go to high bandwidth ASC using the seismic script, but we lost lock as soon as I thought of that.

Next plan: go to lownoise length control, skip lownoise asc, go to the final spots and camera servos, stay in HBW ASC and wait for the 1 Hz ring up and see if we can ride it out this way.

Attached scope screenshot shows the 0.6 Hz oscillation disappearing as soon as Oli flipped the length and pitch estimator switches OFF.

Images attached to this report

H1 General - OPS Wednesday EVE shift start

ryan.crouch@ligo.org — Wed, 22 Oct 2025 16:21:11 -0700

Author: ryan.crouch@ligo.org

Report ID: 87657

TITLE: 10/22 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 21mph Gusts, 17mph 3min avg
Primary useism: 0.05 μm/s
Secondary useism: 0.30 μm/s
QUICK SUMMARY:

Microseism is decreasing over the past ~14 hours
Wind has been rising the past 2.5 hours
We're at MAX_POWER currently

H1 ISC - Comment to reverted changes to ASC gains, increased MICH LSC gain

elenna.capote@ligo.org — Wed, 22 Oct 2025 15:46:15 -0700

Author: elenna.capote@ligo.org

Report ID: 87656

Actually, we just realized we've been forgetting to change the MICH LSC gain before powering up, and looking back the last several locklosses have been due to MICH ringing up. I added a line in DRMI_TO_POP to increase the MICH2 gain to 2. I'm not sure if this is the best permanent solution, but it means we won't forget for now.

H1 ISC - Comment to reverted changes to ASC gains, increased MICH LSC gain

elenna.capote@ligo.org — Wed, 22 Oct 2025 15:39:26 -0700

Author: elenna.capote@ligo.org

Report ID: 87655

To add to today's mysteries, I tried raising CHARD P gain by 20% in HBW to see if that would stabilize us, but that caused a lockloss, indicating that maybe CHARD P HBW is marginal.

We also had a lockloss while I was measuring the CHARD P HBW OLG, but I was running an injection that I had run earlier today, so that also doesn't make sense to me as being the cause.

We just tried powering up without moving the spots, but had a lockloss as soon as we got to 60 W.

H1 SEI - Comment to BRSY not damping like it should, bypassed, not used for now

jim.warner@ligo.org — Wed, 22 Oct 2025 13:32:08 -0700

Author: jim.warner@ligo.org

Report ID: 87653

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.

H1 DetChar - Comment to Witness channels of the set of near-30Hz and near-100Hz combs at LHO

joan-rene.merou@ligo.org — Wed, 22 Oct 2025 13:16:56 -0700

Author: joan-rene.merou@ligo.org

Report ID: 87652

After determining in which channels the peaks appear present, we have studied the coincidence of changes in the comb heights versus the bias in the H1:SUS-ITMY_L3_ESDAMON_DC_OUT16. The following figure shows the coincidences between the changes in the relative amplitude of the first harmonic of each comb (sort of SNR) in DARM and the mean counts in H1:SUS-ITMY_L3_ESDAMON_DC_OUT16 across time. It can be seen that previously to May 2nd, the channel count was set to 60. Once it changed to around -223 after that date, the SNR of the peaks overall increased in a sudden way. Afterwards in June 13th when the count was reduced to 0, most peaks got a much lower SNR at the same time.

Images attached to this report

Non-image files attached to this report

first_harmonic_evolution_full.pdf

first_harmonic_evolution.pdf

H1 ISC - locking today: reverted changes to ASC gains, increased MICH LSC gain

sheila.dwyer@ligo.org — Wed, 22 Oct 2025 12:50:55 -0700

Author: sheila.dwyer@ligo.org

Report ID: 87651

We've had a lot of 0.6Hz wobbling in the move spots state, so Elenna made the move spots a2l gains different from final (undoing a change from this spring), and made the move spots ones the same a2l gains as they were before the camera bump (87473)

Attached is a comparison of the build ups in the move spots states before and after this change, things look about the same, so this hasn't fixed the wobbles.

This isn't our main locking problem today, it doesn't seem to be causing our locklosses and gets better as we power up.

Images attached to this report

H1 ISC - Comment to Incorrect Calibration for H1:OMC-REFL_A_LF channel

jennifer.wright@ligo.org — Wed, 22 Oct 2025 11:54:43 -0700

Author: jennifer.wright@ligo.org

Report ID: 87650

TJ found that this filter bank was monitored in the H1 LSC model so we accepted the diff in OBS and SAFE sdf tables.

H1 ISC - Incorrect Calibration for H1:OMC-REFL_A_LF channel

jennifer.wright@ligo.org — Wed, 22 Oct 2025 11:38:58 -0700

Author: jennifer.wright@ligo.org

Report ID: 87648

Jennie W, Sheila

I noticed yesterday that the power reported as being reflected from the OMC is more than the power reported entering HAM6 (see this alog #87629). This does not affect any controls, but it does affect anyone who is using this channel to do comissioning tests.

Sheila checked this alog for the calibration of OMC-REFL_A PD, alog #65082. It looks like there should be a -20dB switch on in the filter bank when the gain is set to 20dB:

FM7/8 should be the inverse of H1:OMC-REFL_A_DC_GAINSETTING (e.g. enable "-20dB" if the gain is 20dB)

Checking the screen we found the gain setting was set to 0 on the front-end side but the '-20dB filter bank is still turned on. We have turned this filter bank off (see image with relevant parts circled), but the front-end H1:OMC-REFL_A_LF_OUT value still does not match the Beckhoff value, H1:OMC-REFL_A_DC_POWER.

Looking back at our last long lock (when the -20dB filter was still on) you can see that the OMC-REFL_A_LF_OUT16 and OMC-REFL_A_DC_POWER are off by a factor of 100 even though they are both supposed to be in mW. Therefore our switch off of the -20dB filter will not correct this problem and the rest of the calibration of this PD in the front-end filters needs more investigation.

ISC, OpsInfo

Images attached to this report

H1 ISC - Comment to reverted changes to ASC gains, increased MICH LSC gain

oli.patane@ligo.org — Wed, 22 Oct 2025 11:11:55 -0700

Author: oli.patane@ligo.org

Report ID: 87649

The ringup and lockloss in OMC_WHITENING was indeed the usual 1 Hz ringup

Images attached to this report

H1 ISC - Comment to reverted changes to ASC gains, increased MICH LSC gain

david.barker@ligo.org — Wed, 22 Oct 2025 10:49:00 -0700

Author: david.barker@ligo.org

Report ID: 87647

Following the reversion of gains in lscparams.py and the reload of ISC_LOCK, I also reloaded the nodes which import this file but do not use the modified lines in order to green-up GRD-CFC. Nodes loaded are:

ALIGN_IFO,ALS_COMM,ALS_DIFF,ALS_XARM,ALS_YARM,CAMERA_SERVO,H1_MANAGER,IMC_LOCK,INIT_ALIGN,ISC_DRMI,LASER_PWR,LOCKLOSS_SHUTTER_CHECK,OMC_LOCK,SEI_CONF,SEI_ENV,SQZ_FC,SQZ_MANAGER,SUS_CHARGE,TCS_ITMX_CO2_PWR,TCS_ITMY_CO2_PWR,TEST,THERMALIZATION,TMS_SERVO,VIOLIN_DAMPING

LHO VE - Wed CP1 Fill

david.barker@ligo.org — Wed, 22 Oct 2025 10:42:43 -0700

Author: david.barker@ligo.org

Report ID: 87646

Wed Oct 22 10:08:38 2025 INFO: Fill completed in 8min 34secs

Gerardo confirmed a good fill curbside

Images attached to this report

H1 ISC - reverted changes to ASC gains, increased MICH LSC gain

sheila.dwyer@ligo.org — Wed, 22 Oct 2025 09:37:43 -0700

Author: sheila.dwyer@ligo.org

Report ID: 87645

Sheila, TJ, Oli, Matt

We reverted the ASC gain changes (87582) setting INP1 P to 1 and CSOFT P to 25 at MAX power (rather than 30). Most of our locklosses overnight were from states before Max power, so the CSOFT P gain can't have been the problem, but we are undoing it for now just for the sake of reverting recent changes.

We looked at one of the overnight locklosses, it seems that MICH is ringing up at 4.7 Hz. Since Oli is sitting at 2W DCreadout to damp violin modes, we measured the MICH OLG there, and we see it is pretty close to unstable at 5Hz, with low coherence there. We added a factor of 2 gain in LSC MICH2, to bring the UGF to 10 Hz similar to the references, and give us 35 degrees phase margin.

Next we checked the SRCL UGF, which is also locked on POP45, and it's gain looks low by a factor of 5 compared to the reference. This loop has a large phase bubble so it's still stable. POP 45 whitening gain and filters seem to be the same as a few days ago, and the POP LF power is the same as it was a few days ago at 2W. PRCL gain also looks low compared to the reference, but is stable.

We were able to get to OMC_WHITENING (almost to low noise), but while we were sitting there we had the old ring up. We tried manually increasing the CSOFT P gain to 30, but the osciallation had already grown large and we lost lock anyway. I've now put the csoft P gain back to 30 in max power in the guardian.

Images attached to this report

H1 General - Ops Day Shift Start

oli.patane@ligo.org — Wed, 22 Oct 2025 07:39:41 -0700

Author: oli.patane@ligo.org

Report ID: 87644

TITLE: 10/22 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 6mph Gusts, 4mph 3min avg
Primary useism: 0.04 μm/s
Secondary useism: 0.45 μm/s
QUICK SUMMARY:

Currently in IDLE due to locking issues and high violins from overnight. Going to start relocking and hopefully an LSC expert will be in by the time we make it to the LSC ringup issues.

H1 OpsInfo - H1 set to Idle

jenne.driggers@ligo.org — Wed, 22 Oct 2025 05:36:52 -0700

Author: jenne.driggers@ligo.org

Report ID: 87643

I've just set H1 Manager and H1 Notify to IDLE. And I set ISC_LOCK to DOWN so it's sitting in Prep for locking (Since Manager had just requested NLN before I caught it).

When I woke up and had a look at control room screens, I saw that the violins were *very* high, as a result of our many attempts to lock (which I had suggested Ibrahim do, when he and I talked at midnight). Anyhow, there's no way the IFO is going to lock itself with these violin ringups, and it's ~2 hours until shift start, so I'm just setting the IFO to DOWN to at least stop making the violin modes worse.

I hope I've done it correctly, in a way that won't wake Ibrahim up, since he's already been up with the IFO all night (see his many alogs).

Attached is a screenshot of the violins at our last lock attempt. Certainly these will need to be addresed as we relock in the morning. I'm not sure if they are part of the reason it's been challening to relock after maintenance - I assume not, but they definitely could be causing trouble even if Ibrahim was able to fix some guardian things (I didn't look carefully at / read about his overnight work yet).

ISC

Images attached to this report

H1 ISC - OPS OWL Shift: Unstable LSC Loops

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 03:02:42 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87640

After some digging, I found that this is not a new issue and was commented on briefly earlier today.

Alog 87625 shows a near-identical screenshot to the attached MICH LSC ringup, which Oli was experiencing during their DAY shift and no doubt Ryan C also experienced during EVE.

In this alog Sheila noted: "This change should have made a 5% change in the loop gain, so if this was the reason for the lockloss one of our loops is very close to unstable."

I believe since we've lost lock around here for the fifth time now, with all of them showing this ringup, that one of our loops is probably very close to unstable.

What's weird is that from the wording of that alog - the power scaling reversion should have fixed this issue - but it didn't?

So either the power scaling change reversion wasn't loaded/done OR this is an entirely seperate issue.

Well, I checked and it seems this was indeed reverted and we're scaling based on IMC_PWR_IN_OUTMON.

Maybe this is a seperate loop instability issue or a microseism issue or a combination then..

H1 Lockloss Tool is Tagging ADS Excursion on all of these, if it's relevant.

Images attached to this report

H1 ISC - Comment to OPS OWL Shift: Unstable LSC Loops

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 02:57:14 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87642

Well, it's been two locklosses now and the same thing is happening - The only changes I can think of are the gain changes made to INP P (-1 to -2) and CSOFT P (25 to 30) gains (alog 87582) that were put there to avoid the 1Hz ringup after NLN. I frankly have no idea how these would affect powerup. I trended the gains with the ringup but did not find that they happened during a gain change or anything of the sort so I'm doubting this. Trended the values of CSOFT_P and INP_P with the ring-up and they don't seem to be affecting it other than CSOFT_P sees it later on (as expected).

Just checked to confirm the first time this issue has happened was after maintenance and indeed it was. The lock acquisition before the CSOFT P and INP 1 gains were changed did not see even a small ringup in the MICH.

What I can also confirm is that it's a 3.5Hz ringup and it seems to happen during powerup to 25W and not always in the same state. Sometimes it's at MOVE_SPOTS and sometimes it's after. I then checked whether it happens a set time after powerup or sometime spontaneously after 25W node. Sometimes it happens 8 minutes after POWER_25W; sometimes 10 minutes and other times 13 minutes after 25W.

Currently out of ideas. Letting H1 go automatic. Either way microseism is quite high. If I get called back, the next step is to step through POWER_25W or wait at POWER_10W and see if the ringup eventually happens.

Attached trends of the ringup at different times in last 24 hrs as well as the last time it didn't happen.

Images attached to this report

H1 ISC - Comment to OPS OWL Shift: Unstable LSC Loops

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 01:23:16 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87641

I reloaded the guardian at the next Lockloss (which just happened in the same place). It was indeed reloaded prior though at 15:21 (with the first ringup happening at 15:18, and the alog reporting reversion at 15:53).

Thus, this seems to be an unrelated LSC Loop instability.

I will keep investigating.

H1 General - Comment to OPS OWL Shift: DRMI Lock Issues

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 00:46:52 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87639

Lockloss at MOVE_SPOTS with ASC signals oscillating wildly (warning of "waiting for ADS to converge"), same signal as the 4.5Hz MICH oscillation Ryan C reported during his shift. Confused what could be causing this. It seems like oscillating ASC and non-converging ASC were there throughout the lock acquisition. Querying the alog and wiki now. I've attached a screenshot of the oscillating signal, loudest in MICH during powerup ~25W to MAX_POWER

Images attached to this report

H1 General - Comment to OPS OWL Shift: DRMI Lock Issues

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 00:28:17 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87638

Well, it seems that as soon as I was writing this, DRMI was conspiring against my statement and actually locked. We're now at PREP_DC_READOUT_TRANSITION.

Getting "Low Recycling Gain" flashing during CARM but it (so far) has not caused a lockloss.

DHARD_P and Y look to be the noisiest signals currently. Let's see what happens.

H1 General - Comment to OPS OWL Shift: DRMI Lock Issues

ibrahim.abouelfettouh@ligo.org — Wed, 22 Oct 2025 00:16:27 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87637

Called Jenne (first on call list) after managing to accomplish nothing.

Flashes are good. Alignment is fine. DRMI is locking for 10s before unlocking due to what looks like environmental instability. It seems that 90th percentile+ microseism is just too high to lock - which doesn't make a lot of sense because we've locked with it at a similar level before. Since there aren't any glaring alignment or locking issues other than instability, we assumed it to be due to the environment.

Since microseism seems to be maybe going down slowly, advice given was to set IFO to lock automatically, and if it calls again, then I try again. If this becomes a cycle, then ~4/5 I was given the ok to put IFO in IDLE to avoid violin mode ringups (just like yesterday night). Be back soon (hopefully not).

H1 General - OPS OWL Shift: DRMI Lock Issues

ibrahim.abouelfettouh@ligo.org — Tue, 21 Oct 2025 23:39:34 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 87636

Got called at 11:15 PM (PT) due to IFO unable to lock DRMI. Ryan C had warned me before the end of his shift. The issue doesn't seem to be alignment since Initial Alignment was run 3 times over the course of the EVE shift and flashes look sufficient (if not great) to lock. I touched up the BS and PRM in PRMI to no avail. Requested MICH_FRINGES and we'll see if that helps the PRMI lock.

SEI_CONF is not in its nominal position but that seems intentional since the EY sensor correction was turned off today (alog 87634) due to an unrelated issue that happened during maintenance.

In terms of microseism, it's high but it's not that high and we've locked at this level with higher winds in the past week.

I will continue monitoring to see what happens but will resort to the call list if I'm not getting anywhere. I believe we've been unlocked for over 24 hrs now.

H1 General - OPS Tuesday EVE shift summary

ryan.crouch@ligo.org — Tue, 21 Oct 2025 22:01:23 -0700

Author: ryan.crouch@ligo.org

Report ID: 87635

TITLE: 10/22 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: The furthest I've been able to get was MAX_POWER, I had several high state locklosses at different states (REDUCE_RF45, MOVE_SPOTS, MAX_POWER). I minimized the SHG rejected power while relocking as I saw the notification. After the second IA things went pretty well at first, microseism was still at about the same level as earlier. One of our locklosses at ALS had a BRS_GLITCH tag, which are rare. All of the LLs had an ADS_EXCURSION tag and most of the higher state locklosses I saw a ~4.5Hz oscillation in MICH. I started another IA at 21:45 as DRMI is taking a while to lock and it ran through CHECK_MICH on the last aquistion. Microseism has remained elevated and even increased a tiny bit. The IMC is really struggling to relock after INPUT_ALIGN, its been trying for the past 6 minutes as of 05:00.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
22:43	PSL	Keita	Optics lab	lOCAL	ISS array	01:37
23:03	EE	Marc, Fil	MY	n	Replacing power supply	23:23
00:34	SEI	Jim, Fil, Marc	EndY	N	Check on BRS	01:00

00:21 Going through PRMI didn't help the power but it did improve the beamspot, then in DRMI camera spot looked good after I tapped on SRM a bit but ASC turning on strongly knocked it out.
00:45 IA
01:44 UTC Lockloss at REDUCE_RF45, ~4.5 Hz ringup seen in MICH and PRCL
02:35 UTC MOVE_SPOTS lockloss, same ~4.5Hz ringup
03:24 UTC MAX_POWER lockloss
04:20 UTC Earthquake mode

H1 SEI - BRSY not damping like it should, bypassed, not used for now

jim.warner@ligo.org — Tue, 21 Oct 2025 18:35:22 -0700

Author: jim.warner@ligo.org

Report ID: 87634

Something happened with BRSY this morning during maintenance that caused it to ring up more than normal and now the damping is not behaving quite as expected. For now, I have paused the ETMY sensor correction guardian with the BRSY out of loop and turned off the output of the BRS so it won't be used for eq mode, should that transition happen.

So far today, I did a bunch of "recapturing frames" in the BRS C# code, which has usually fixed this issue in the past. We also restarted the beckhoff computer, then the plc, C# and epics ioc. This did not recover the BRS either. Marc, Fil and I went to EY and looked at the damping drive in the enclosure and I think it was behaving okay. When the drive came on, the output would reach ~1.8V, then go to 0V when it turned off.

I've contacted UW and we will take a look at this again tomorrow.

H1 SUS - Added option for v1 Pitch/Length OSEM estimator filters

edgard.bonilla@ligo.org — Tue, 21 Oct 2025 18:23:21 -0700

Author: edgard.bonilla@ligo.org

Report ID: 87633

Added an option to the OSEM estimator filters for PR3/SR3 that allows us to get v1 filters.

The v1 filters use the model at the first two L/P resonances of the SR3 and PR3 suspensions. [see images attached for an example of v2 vs v1]

The functions that construct these blends are the same ones posted in [LHO: 87613] and [LHO: 87596]:

blend_{PR3,SR3}_{length,pitch}v2_LP_est.m
The files must be run with the argument 'v1' to get the v1 filters out. For example, blend_PR3_lengthv2_LP_est('v1') will get the v1 filters for H1 PR3 in length.

If you run them with anything else (including no argument), they will get the v2 filters, same as before. However, I suggest running them as blend_PR3_lengthv2_LP_est('v2') in automated code so everything is clean for loading the filters into foton.

These changes have been committed to the SVN under revision 12745.

SUS

Images attached to this report

H1 SEI - BRS EY restarted

erik.vonreis@ligo.org — Tue, 21 Oct 2025 17:42:14 -0700

Author: erik.vonreis@ligo.org

Report ID: 87632

[Jim, Jonathan, Erik]

BRS EY was restarted to try to damp high amplitude oscillations that started around 08:50 PDT.

We shutd down the processes in this order:

Epics

University of Washington process

TwinCAT PLC software

Then we restarted the server and started the same process in reverse order from desktop icons.

The restart did not have any apparent effect on the oscillations.

CDS

H1 General - IMC and Input jitter to ISS measurements

matthewrichard.todd@ligo.org — Tue, 21 Oct 2025 17:37:00 -0700

Author: matthewrichard.todd@ligo.org

Report ID: 87630

M. Todd, S. Dwyer

This morning we were not locked before Tuesday maintanence, so I skipped the HWS transient measurement and started immediately with the IMC and input jitter measurements I had planned. For posterity, the IFO was unlocked but the IMC was locked and input power taken to 62W, and then the ISS was turned on.

I continued attempting to tune injections of the IMC DOFs, but was not able to see any coherence to either the corresponding DOF error signal or the ISS loop, in the bands I was interested in. I think the DOF loop bandwidths are just tooo low for this kind of measurement without saturating the suspensions. I may continue to try some very small bands but nothing above 15 Hz anymore, as I'm just not convinced there is any reasonable coupling to the ISS there. The list of figures shows the injections from this injection set.

I then took some coherence measurements of the various sensors to the IMC ASC/LSC with the ISS loops during a quiet locked time to wrap my head around things better, and noticed a large coherence between the ISS first loop diodes and the ISS second loop witness sensor. I was initially confused by this but after talking with Keita, this is not surprising as there is most likely intensity noise that the 2nd loop is seeing and suppressing and thus imposing that suppression into the first loop sensors (thus the coherence).

Then I did some input jitter excitations, and without actually calculating the transfer functions ( those estimates will come later in a comment using Sheila's excess power code, due to the lack of coherence to ISS ) I don't think the ISS loops are limited by the input jitter at these frequencies. The list of figures shows the plots from this injection set.

List of Figures

Non-image files attached to this report

h1_imc_pzt_pit_out_dq_during_imc_injection_PZT_PIT_20251021.pdf

h1_psl_iss_secondloop_rin_outer_out_dq_during_imc_injection_PZT_PIT_20251021.pdf

h1_imc_pzt_yaw_out_dq_during_imc_injection_PZT_YAW_20251021.pdf

h1_psl_iss_secondloop_rin_outer_out_dq_during_imc_injection_PZT_YAW_20251021.pdf

h1_imc_dof_1_y_in1_dq_during_imc_injection_DOF_1_Y_20251021.pdf

h1_psl_iss_secondloop_rin_outer_out_dq_during_imc_injection_DOF_1_Y_20251021.pdf

h1_imc_dof_3_p_in1_dq_during_imc_injection_DOF_3_P_20251021.pdf

h1_psl_iss_secondloop_rin_outer_out_dq_during_imc_injection_DOF_3_P_20251021.pdf

H1 ISC - Comment to Optical Gain and output loss checks with hot OM2 on 4th September

jennifer.wright@ligo.org — Tue, 21 Oct 2025 17:18:54 -0700

Author: jennifer.wright@ligo.org

Report ID: 87629

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.

Images attached to this report

Non-image files attached to this report

P_as_vs_P_OMC_REFL_gps_start_1441050554_Sep_4th__1_hr_25_mins_into_lock.pdf

P_as_vs_P_OMC_REFL_gps_start_1441056274_Sep_4th__2_hrs_59_mins_into_lock.pdf

LHO VE - X-End BSC9 Annulus Ion Pump Status

gerardo.moreno@ligo.org — Tue, 21 Oct 2025 17:17:03 -0700

Author: gerardo.moreno@ligo.org

Report ID: 87631

Work done under WP 12845, used a ladder to get close to the ion pump body, and used a wrench to hit the body a couple of times. Controller not railed after "fix".

Current dropped some at a very slow rate, but is not red anymore on the MEDM screen.

WP is closed now.

Images attached to this report

H1 General - Comment to OPS Tuesday EVE shift start

ryan.crouch@ligo.org — Tue, 21 Oct 2025 16:49:33 -0700

Author: ryan.crouch@ligo.org

Report ID: 87627

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.

PEM

Images attached to this report

H1 CDS - MY PEM AA Chassis

filiberto.clara@ligo.org — Tue, 21 Oct 2025 16:46:13 -0700

Author: filiberto.clara@ligo.org

Report ID: 87628

WP 12850

Chassis found with positive 15V LED powered off. Side rack 1A fuse was blown. Replaced shorted C12 capacitor on the first D070081 board. Chassis reinstalled.

PEM

LHO VE - Quarterly Functionality Test Performed on EY/MY Turbo Pumps and Purge Air Skid

jordan.vanosky@ligo.org — Tue, 21 Oct 2025 16:40:45 -0700

Author: jordan.vanosky@ligo.org

Report ID: 87619

Procedure checklist for both stations completed.  No issues were identified at this time.

MY: Scroll pump hours: 98.5
       Turbo pump hours: 236
       Crash bearings: 100%

EY: Scroll pump hours: 89.9
       Turbo pump hours: 1297
       Crash bearings: 100%
 
Closing WP 12843 FAMIS 31280 and 31288

EY purge air compressor was ran for ~3 hours, dew point mointor quickly reached <-40 degF and at time of shut down was reporting -76 degF.

New system, so there are only a few run hours.

3 hours total, distributed between the three scroll compressors.

Images attached to this report

H1 General - Ops Day Shift End

oli.patane@ligo.org — Tue, 21 Oct 2025 16:36:01 -0700

Author: oli.patane@ligo.org

Report ID: 87626

TITLE: 10/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Currently trying to relocking. Having some trouble, partially due to extremely high secondary microseism, and partly due to unknown issues.
LOG:

14:30UTC Detector in IDLE due to high secondary microseism
20:47 Start relocking
   20:47 Initial alignment
   21:25 Initial alignment done
   Lockloss from LOWNOISE_LENGTH_CONTROL - ringup started when gains were changed, lost lock 10s later

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:06	FAC	Eric	EX, EY	n	Lubricating fans	16:06
15:08	VAC	Gerardo	EX	n	Ion pump	15:44
15:09	VAC	Jordan	MY, EY	n	Turbo pump tests	18:35
15:15	FAC	Kim, Nellie	HAM Shack	n	Tech clean	16:08
15:19	FAC	Tyler	EX	n	Joining Eric	16:06
15:45	EE	Fil	LVEA	n	Swapping MC lower stage satamps	17:23
15:46	FAC	Randy	LVEA	n	Inspections	16:06
16:05	FAC	Mitchell	LVEA	n	Moving stuff to SEI rack	16:12
16:08	FAC	Kim, Nellie	LVEA	n	Tech clean	17:35
16:58	FAC	Tyler	LVEA, MX, MY	n	3IFO checks	18:43
17:00	EE	Marc	LVEA	n	Joining Fil	17:06
17:08	SEI	Jim, Randy	LVEA	n	Looking around BSC2	17:59
17:24		Keita, Rahul	OpticsLab	y(local)	ISS Array	19:48
17:31	EE	Fil	EX, EY	n	Checking out fibers and figuring out power supply issue	19:21
17:35	SEI	Jim	LVEA	n	Working on HAM7 SEI satamps	17:59
17:35	FAC	Nellie	EY	n	Tech clean	18:33
17:36	FAC	Kim	EX	n	Tech clean	19:23
17:36	EE	Marc	EX	n	Replacing failed fan	18:41
17:46	FAC	Randy	EY, EX	n	Checks	19:37
18:45	EE	Marc	EX	n	Get ready to restart EX pump controller	19:45
19:30	VAC	Gerardo	EY	n	Turning off purge air pumps	20:26
19:37	FAC	Randy	XTube	n	Caulking the tube	21:59
20:03		RyanC	LVEA	n	Sweeping	20:26
21:49	EE	Marc, Fil	MY	n	Investigating PEM power supply failure	22:11
22:43	PSL	Keita	Optics lab	lOCAL	ISS array	23:43
23:03	EE	Marc, Fil	MY	n	Replacing power supply	23:23

H1 General - OPS Tuesday EVE shift start

ryan.crouch@ligo.org — Tue, 21 Oct 2025 15:59:56 -0700

Author: ryan.crouch@ligo.org

Report ID: 87621

TITLE: 10/21 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
SEI_ENV state: USEISM
Wind: 4mph Gusts, 1mph 3min avg
Primary useism: 0.07 μm/s
Secondary useism: 0.49 μm/s
QUICK SUMMARY:

We are still trying to recover lock post maintenance
2ndary microseism is still high, right around the 90th percentile, but the wind is low
- Primary also seems elevated
BRS-Y's velocity is high, Jim's looking into it, this happened about a month ago as well alog86985

H1 ISC - Comment to gain scaling change reverted

elenna.capote@ligo.org — Tue, 21 Oct 2025 15:57:05 -0700

Author: elenna.capote@ligo.org

Report ID: 87625

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.

Images attached to this report

H1 ISC - gain scaling change reverted

sheila.dwyer@ligo.org — Tue, 21 Oct 2025 15:53:32 -0700

Author: sheila.dwyer@ligo.org

Report ID: 87624

I set the gain scaling back to use IMC INput power, since we had an unusual lockloss at LSC length control Elenna sees is related to LSC loop gain changes.

This change should have made a 5% change in the loop gain, so if this was the reason for the lockloss one of our loops is very close to unstable.

H1 SUS - Weekly In-Lock SUS Charge Measurement FAMIS

ryan.crouch@ligo.org — Tue, 21 Oct 2025 15:32:12 -0700

Author: ryan.crouch@ligo.org

Report ID: 87622

Closes FAMIS28428, last checked alog87482.

Injections were not made as we were not locked this morning.

LHO VE - Comment to X-End Noisy Power Supply

daniel.sigg@ligo.org — Tue, 21 Oct 2025 15:31:41 -0700

Author: daniel.sigg@ligo.org

Report ID: 87623

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.

H1 TCS - TCS Chiller Water Level Top-Off - Biweekly

ryan.crouch@ligo.org — Tue, 21 Oct 2025 15:28:10 -0700

Author: ryan.crouch@ligo.org

Report ID: 87437

Closes FAMIS27826, last checked in alog87432.

Y was at 9.5 I added 300ml and brought it up to 10.3.

X was at 29.8, I added 250ml and brought it up to 30.4.

H1 SUS - Sat Amps Modified: Lower Stages MC1, MC2, MC3, PR3, and SR3

filiberto.clara@ligo.org — Tue, 21 Oct 2025 14:39:57 -0700

Author: filiberto.clara@ligo.org

Report ID: 87620

WP 12844
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
MC1 M2	S1100182	S1100148	ULLLURLR
MC1 M3	S1100176	S1100135	ULLLURLR
MC3 M2	S1100069	S1100106	ULLLURLR
MC3 M3	S1100123	S1100093	ULLLURLR
PR3 M2	S1100063	S1000274	ULLLURLR
PR3 M3	S1100113	S1000277	ULLLURLR
MC2 M2	S1100110	S1100169	ULLLURLR
MC2 M3	S1000294	S1100174	ULLLURLR
SR3 M2	S1100105	S1100146	ULLLURLR
SR3 M3	S1100074	S1100134	ULLLURLR

F. Clara, J. Kissel, O. Patane

SUS

LHO VE - Comment to X-End Noisy Power Supply

marc.pirello@ligo.org — Tue, 21 Oct 2025 14:28:10 -0700

Author: marc.pirello@ligo.org

Report ID: 87618

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

H1 SUS - SR3/PR3 L Estimator installed and on (P estimator updated too)

oli.patane@ligo.org — Tue, 21 Oct 2025 13:28:51 -0700

Author: oli.patane@ligo.org

Report ID: 87616

Edgard, Oli

Edgard got everything done for the PR3 and SR3 L estimator, so I was able to install all the filters and turn them on. Along with the L to L estimator parts, this also included L to P models, and involved updates to the P estimator's P to P and P to L fits.

We are running the L estimator and the updated P estimator as of 2025-10-21 20:18:00 UTC.

Images attached to this report

H1 General - LVEA swept

ryan.crouch@ligo.org — Tue, 21 Oct 2025 13:16:24 -0700

Author: ryan.crouch@ligo.org

Report ID: 87615

The LVEA has been swept, no items of note.

H1 ISC - Comment to Optical Gain and output loss checks with hot OM2 on 4th September

jennifer.wright@ligo.org — Tue, 21 Oct 2025 13:04:14 -0700

Author: jennifer.wright@ligo.org

Report ID: 87614

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.

Images attached to this report

H1 SUS - SR3 OSEM estimator blends updated for L/P

edgard.bonilla@ligo.org — Tue, 21 Oct 2025 12:47:07 -0700

Author: edgard.bonilla@ligo.org

Report ID: 87613

We built on the templates set by the PR3 L/P estimator blends [see LHO: 87596] to create Length and Pitch blend filters for the SR3 OSEM estimator.

The functions that make the model and OSEM filters live in:
blend_SR3_lengthv2_LP_est.m
blend_SR3_pitchv2_LP_est.m

The files were committed to the SVN at (svnRoot)/sus/trunk/HLTS/Common/FilterDesign/Estimator/ under revision 12741.

make_EST_blends.m in the same folder should work for getting these onto the real-time model.

SUS

Images attached to this report

H1 SUS - SR3 L/P OSEM estimator fits

edgard.bonilla@ligo.org — Tue, 21 Oct 2025 12:34:13 -0700

Author: edgard.bonilla@ligo.org

Report ID: 87612

Follow up to Oli's measurements in [LHO: 87363 LHO: 87611].

We did the fitting for the SR3 OSEM estimator with the M1 drive measurements from today plus the Suspoint measurements from two weeks ago.

The plant is not nearly as reciprocal as the PR3 plant, I wonder what that means.

The fits had to be obtained by tweaking over the PR3 OSEM estimator model posted in [LHO: 87593]. This worked really fast, and produced very clean results. I think we might use this method as a way to retune the estimators in the future.

The .pdf attached has the image of the Estimator L/P models for bookkeeping.

The fits are contained in fits_H1SR3_LP-2025-10-07.mat have been uploaded to the SVN under revision 12740 to

(svnroot)/sus/trunk/HLTS/Common/FilterDesign/Estimator.

Here are the ZPKs for the model

_____________________________________________________________________________

SUSPOINT TO M1

Suspoint L to M1 L fit
zpk([0,0,-0.06-4.33i,-0.06+4.33i,-0.051-7.177i,-0.051+7.177i,-0.089-15.255i,-0.089+15.255i],[-0.073-4.136i,-0.073+4.136i,-0.07-4.666i,-0.07+4.666i,-0.071-9.92i,-0.071+9.92i,-0.155-18.168i,-0.155+18.168i],-0.001)

Suspoint L to M1 P fit
zpk([0,0,0.935-6.789i,0.935+6.789i,-1.049-6.865i,-1.049+6.865i,-1.085-18.474i,-1.085+18.474i,0.833-18.561i,0.833+18.561i],[-0.078-4.113i,-0.078+4.113i,-0.058-4.655i,-0.058+4.655i,-0.071-9.916i,-0.071+9.916i,-0.165-13.116i,-0.165+13.116i,-0.221-18.058i,-0.221+18.058i,-0.053-21.596i,-0.053+21.596i],0.383)

Suspoint P to M1 L fit
zpk([0,0,-0.103-4.364i,-0.103+4.364i,-0.095-9.007i,-0.095+9.007i,-0.071-17.115i,-0.071+17.115i],[-0.071-4.094i,-0.071+4.094i,-0.055-4.64i,-0.055+4.64i,-0.062-9.948i,-0.062+9.948i,-0.158-18.146i,-0.158+18.146i],0)

Suspoint P to M1 P fit
zpk([0,0,-0.002-4.162i,-0.002+4.162i,0.006-4.65i,0.006+4.65i,0.036-5.615i,0.036+5.615i,-0.011-9.179i,-0.011+9.179i,-0.065-9.837i,-0.065+9.837i,-0.052-14.212i,-0.052+14.212i,-0.017-21.873i,-0.017+21.873i],[-0.06-4.105i,-0.06+4.105i,-0.01-4.178i,-0.01+4.178i,-0.02-4.629i,-0.02+4.629i,-0.028-4.68i,-0.028+4.68i,-0.019-9.793i,-0.019+9.793i,-0.045-9.975i,-0.045+9.975i,-0.139-13.128i,-0.139+13.128i,-0.041-21.608i,-0.041+21.608i],-0.001)

M1 DRIVE TO M1

M1 drive L to M1 L fit
zpk([-0.067-4.297i,-0.067+4.297i,-0.003-5.174i,-0.003+5.174i,-0.024-12.283i,-0.024+12.283i],[-0.064-4.12i,-0.064+4.12i,-0.057-4.635i,-0.057+4.635i,-0.072-9.904i,-0.072+9.904i,-0.155-18.168i,-0.155+18.168i],0.136)

M1 drive L to M1 P fit
zpk([1.502-5.563i,1.502+5.563i,-1.589-5.824i,-1.589+5.824i,-14.284,14.718,1.462-17.431i,1.462+17.431i,-1.276-17.775i,-1.276+17.775i],[-0.068-4.121i,-0.068+4.121i,-0.063-4.638i,-0.063+4.638i,-0.072-9.905i,-0.072+9.905i,-0.158-13.118i,-0.158+13.118i,-0.163-18.132i,-0.163+18.132i,-0.056-21.582i,-0.056+21.582i],0.078)

M1 drive P to M1 L fit
zpk([1.399-5.266i,1.399+5.266i,-1.594-5.6i,-1.594+5.6i,2.034-16.482i,2.034+16.482i,-2.192-17.091i,-2.192+17.091i],[-0.073-4.113i,-0.073+4.113i,-0.06-4.63i,-0.06+4.63i,-0.068-9.924i,-0.068+9.924i,-0.163-13.118i,-0.163+13.118i,-0.143-18.158i,-0.143+18.158i,-0.072-21.583i,-0.072+21.583i],-25.295)

M1 drive P to M1 P fit
zpk([-0.075-4.398i,-0.075+4.398i,0-5.423i,0+5.423i,-0.068-9.979i,-0.068+9.979i,-0.002-20.622i,-0.002+20.622i],[-0.069-4.109i,-0.069+4.109i,-0.051-4.632i,-0.051+4.632i,-0.076-9.938i,-0.076+9.938i,-0.164-13.126i,-0.164+13.126i,-0.074-21.58i,-0.074+21.58i],76.066)

Non-image files attached to this report

fits_H1SR3_LP-2025-10-07.pdf

H1 ISC - Comment to Optical Gain and output loss checks with hot OM2 on 4th September

jennifer.wright@ligo.org — Tue, 21 Oct 2025 12:33:37 -0700

Author: jennifer.wright@ligo.org

Report ID: 87610

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.

Non-image files attached to this report

P_as_vs_P_DCPD__comp_Sep_04.pdf

H1 SUS - (repeat) SR3 measurements for L Estimator

oli.patane@ligo.org — Tue, 21 Oct 2025 12:21:24 -0700

Author: oli.patane@ligo.org

Report ID: 87611

I needed to retake measurements for the SR3 M1 to M1 L estimator in the L and P degrees of freedom because the ones from 87363 didn't have good enough coherence.

Settings:
- ISI in ISOLATED
- SUS in ALIGNED
- Estimators off (using regular damping)
- L DAMP gain to 20% (-0.1), P DAMP gain at 20% (-0.1), Y DAMP gain to 100% (-0.5)

Results:
M1 to M1
/ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/SAGM1/Data/2025-10-21_1600_H1SUSSR3_M1_WhiteNoise_EstL_{L,P}_0p02to50Hz.xml r12738

These have a lot better coherence now

SEI

H1 CAL - Comment to Calibration Sweep 10/18

elenna.capote@ligo.org — Tue, 21 Oct 2025 11:43:04 -0700

Author: elenna.capote@ligo.org

Report ID: 87609

I generated the pydarm report from this measurement. I ended up changing "pro-spring" to False and regenerating.

Non-image files attached to this report

H1_calibration_report_20251018T184336Z.pdf

H1 SEI - HAM7 CPS switched to local timing

jim.warner@ligo.org — Tue, 21 Oct 2025 11:16:25 -0700

Author: jim.warner@ligo.org

Report ID: 87608

Since it was installed, HAM7 ISI has been prone to trips if people are working nearby. Often walking by the chamber is enough, but work in the squeeze racks, HAM6 ISC racks or unplugging electronics from nearby outlets has caused CPS saturations. After talking to Jeff, we decided to try disconnecting HAM7 from the corner timing system and try running the ISI using it's own local 10khz timing clock signal. I pulled the P3 jumper from the H1 CPS and disconnected the timing DB9 that connects HAM7 to the timing system. Position readout seems unchanged before vs. after the change. This shouldn't affect anything else.

LHO VE - Comment to X-End Noisy Power Supply

david.barker@ligo.org — Tue, 21 Oct 2025 11:15:44 -0700

Author: david.barker@ligo.org

Report ID: 87607

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.