aLIGO LHO Logbook

LHO General - Thurs DAY Ops Summary

corey.gray@ligo.org — Thu, 10 Sep 2026 07:52:04 -0700

Author: corey.gray@ligo.org

Report ID: 91862

TITLE: 09/10 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 6mph Gusts, 4mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.11 μm/s
QUICK SUMMARY:

Locking work continues around DRMI & with other spots. Guessing the Relay Tube (with no leaks & MegaCleanroom OFF) is still pumping down.

For the commute, crack sealing dealys on SR240 from Twin Bridges to the ORV park road (not sure where it starts in town)...actually WSDOT notes this chip seal work is from Milepost 8 to 28.

Images attached to this report

H1 SPI - Comment to SPI Readout vs. ISI Sensors: A First Comparison

sina.koehlenbeck@ligo.org — Wed, 09 Sep 2026 19:01:21 -0700

Author: sina.koehlenbeck@ligo.org

Report ID: 91861

Brian pointed me to a set of new data channels that provide calibrated outputs directly in displacement units. Using these channels, I acquired spectra with DTT at UTC 2026-09-09 12:00:00 (BW = 0.01 Hz, 30 averages) and generated the plots that follow

Channels plotted — Angular (RY / Pitch):

Optical lever pitch signals (angular, rad/√Hz):

H1:SPI-H23_OL_ISI_J_PIT_OUT_DQ (ISI 2) — Optical lever ISI J pitch angle
H1:SPI-H23_OL_ISI_K_PIT_OUT_DQ (ISI 3) — Optical lever ISI K pitch angle

ISI blend / CPS RY signals (ISI RY witness channels):

H1:ISI-HAM2_BLND_CPSRY_IN1_DQ (ISI 2) — HAM2 blended CPS RY input
H1:ISI-HAM3_BLND_CPSRY_IN1_DQ (ISI 3) — HAM3 blended CPS RY input

ISI calibrated Cartesian RY signals (rad/√Hz):

H1:ISI-HAM2_CAL_CART_RY_OUT_DQ (ISI 2) — HAM2 calibrated Cartesian RY output
H1:ISI-HAM3_CAL_CART_RY_OUT_DQ (ISI 3) — HAM3 calibrated Cartesian RY output

Differential Z displacement channel (converted to rad/√Hz):

H1:ISI-DIFF_H23_SS_Z_OUT_DQ — Differential H23 SS_Z displacement. Given in nm/√Hz; converted to m/√Hz, then divided by the arm length (15.4 m) to yield rad/√Hz.

Channels plotted — Differential X motion (displacement):

H1:SPI-H23_DIFFDISP_MAIN_OUT_DQ — SPI H23 main differential displacement
H1:ISI-DIFF_H23_SS_X_OUT_DQ — Differential H23 SS_X (CPS + GS13 supersensor)
H1:ISI-HAM2_BLND_CPSX_IN1_DQ (ISI 2) — HAM2 blended CPS X input
H1:ISI-HAM3_BLND_CPSX_IN1_DQ (ISI 3) — HAM3 blended CPS X input
H1:ISI-HAM2_CAL_CART_X_OUT_DQ (ISI 2) — HAM2 calibrated Cartesian X output (GS13)
H1:ISI-HAM3_CAL_CART_X_OUT_DQ (ISI 3) — HAM3 calibrated Cartesian X output (GS13)

All scaled by nm_to_m (nm/√Hz → m/√Hz).

Unit conversions:

OL_ISI_J_PIT and OL_ISI_K_PIT plotted in rad/√Hz
SS_Z converted from nm/√Hz to rad/√Hz by dividing by a length of 15.4 m
Differential X-motion channels scaled from nm/√Hz to m/√Hz (nm_to_m factor)
Angular y-axis units in rad/√Hz; displacement y-axis units in m/√Hz

Images attached to this report

H1 General - Wednesday OPS EVE Shift End

anthony.sanchez@ligo.org — Wed, 09 Sep 2026 19:01:18 -0700

Author: anthony.sanchez@ligo.org

Report ID: 91860

TITLE: 09/10 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: None
SHIFT SUMMARY:

The Mega Clean room was Turnt Off. For What!? You may ask? Because we are trying to get closer to our final LVEA temperature for locking the IFO.
GRB-Short E646174 notification @ 1:24:41 UTC
H1 is now sitting in down er rather Prep for locking..

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
22:35	vac	VACteam	EY	-	vendor visit to EY	23:50
23:42	VAC	Jordan Gerardo	LVEA HAM7	N	Valving swap on HAM7	23:53
00:40	VAC	Gerardo	LVEA	N	Turning Off the Mega Clean room	00:49

H1 ISC - Comment to Morning locking to PRMI, oplev damping solution, Afternoon L2P decoupling, DRMI

jenne.driggers@ligo.org — Wed, 09 Sep 2026 18:32:30 -0700

Author: jenne.driggers@ligo.org

Report ID: 91859

[Gabriele, Jenne]

Gabriele pointed out that the funny MICH OLG almost looks like a strange situation with the BBSS crossover. We tried changing the H1:SUS-BS_M3_DRIVEALIGN_L2L_GAIN from nominal 1, to 0.5 and also 2. This changed the high frequency part of the MICH OLG, but never made it 'better'.

I tried measuring the BBSS M2/M3 crossover, using a template I found in Elenna's directory that looks like it's from alog 91713. Her references from no-arm MICH-only are the green squares. The nominal (gains of 1 everywhere) measurement with DRMI locked (arms off resonance) is red circles. I don't think it makes sense to me why the crossover is so very different right now. I tried changing H1:SUS-BS_M3_DRIVEALIGN_L2L_GAIN as well as H1:SUS-BS_M2_DRIVEALIGN_L2L_GAIN, but never could get the crossover to look like anything sensible.

So, on the one hand, we still don't know why the DRMI OLGs are so weird, but on the other hand we can stay locked with DRMI for ~infinity minutes, as long as we touch up the alignment every 20 minutes or so.

I'm leaving the IFO requested to DOWN, so that when the DRMI finally drifts too much, it won't try to relock until a person is here to watch it.

Images attached to this report

H1 SPI - Comment to SPI P and Y Signals, Now Calibrated with QPDA Dark Noise Fixed

sina.koehlenbeck@ligo.org — Wed, 09 Sep 2026 17:23:20 -0700

Author: sina.koehlenbeck@ligo.org

Report ID: 91858

New plots with noise models.

Images attached to this report

H1 ISC - Morning locking to PRMI, oplev damping solution, Afternoon L2P decoupling, DRMI

elenna.capote@ligo.org — Wed, 09 Sep 2026 17:19:04 -0700

Author: elenna.capote@ligo.org

Report ID: 91850

Sheila, Elenna, Jenne

Morning locking notes

Jenne completed initial alignment by running green initial alignment and through manual initial alignment for X arm IR, PRX, MICH dark, SR align, and SRY. Except for SR2 align, all alignment was touched up by hand.
We tried locking PRMI once without oplev damping, however we lost ALS with a large beamsplitter kick.
The second time we tried locking with oplev damping (using oplev as sensor), and we were successful. PRMI locked for 10 minutes. I touched up the PRM and BS alignment. Sheila still measured a large amount of motion at 0.45 Hz. We think this motion is due to length to pitch coupling on M2.
I tried engaging the L2P decoupling filter in M2 drivealign. We lost lock due to a 19 Hz ringup in MICH. We are not sure if this was caused by the L2P filter or if MICH is unstable. We will remeasure.
After that we had two lockloss on the first PRMI flash. This flash is coincident with oplev damping ramping on, but we realized it is because the damping is not on before the LSC starts triggering. I moved the oplev damping to engage as "prep DRMI" in the ISC DRMI guardian, so it will hopefully help.

At this time we held in down to allow relay tube work, and used the time to measure the oplev damping and try switching to using M3 wit for lower stage damping instead.

I measured the oplev damping OLGs, pitch and yaw. The reference traces use the oplev as the sensor for the damping, and the live traces use the M3 wit as the sensor but a different matrix value that Sheila calculated based on this alog.

We then switched to M2 damping using M3 wits as the sensor, and compared the BS spectra with no lower stage damping, oplev damping, and wit damping, comparison here. We see good suppression of the modes and less sensor noise injection on the M3 wits.

Here is a screenshot of the "OLDAMP" settings we want to use on M2. I want to clarify that even though we are now using the M3 wits as the sensor, the damping is still running through the oplev damping bank on M2.

At this point, we decided to break further and allow Filiberto to update the resistors on the M1 QOSEMs, so our lockloss transient from saturation is reduced.

***

After Fil and Oli finished the sat amp changes, we began locking again. We locked PRMI with M3 wit damping engaged before the triggering occurred so there was no lockloss. Once locked, the guardian disengages the lower stage damping.

Sheila measured the BS motion using oplev and M3 wit without the L2P decoupling engaged but the wit damping off. She checked the MICH and PRCL OLGs and we saw that they were fine. MICH UGF is 8.5 Hz, PRCL is 60 Hz.

I engaged the L2P decoupling, and we saw that low frequency pitch motion was reduced. However, there was still a large 0.45 Hz peak. With the M3 wit damping reengaged, the peak is reduced. See plot

Recipe for successful PRMI: M3 wit damping engaged, L2P decoupling engaged. Once we can reengage MICH ASC, we can turn off the M3 wit damping. I have SDFed the filters for BBSS M2 L2P decoupling 1 2

There is a lot of alignment drift in BS yaw while we sit locked. I had to touch up the aligment by hand.

We stayed in PRMI for 25 minutes.

***

We struggled to lock DRMI, and eventually chose to relock PRMI and fix the alignment. After this, DRMI locked quickly. We lost lock at the 3 f transition, so Sheila went to check we were aligned to REFLAIR 3f diodes. Then, I rephased the diodes while locked in PRMI by injecting a PRCL line and maximizing the height in 27 I, and a MICH line to maximize the height in 135 Q. PRCL, MICH, SDF

With DRMI locked, we saw that the PRCL OLG looked strange, so I also checked the REFLAIR 1f phasing. I made a minimal change to reflair 9 to improve PRCL in I and a 50 deg change in 45 to reduce SRCL in 45 Q. PRCL, SRCL, SDF

Sheila's guardian changes, to improve some problems we faced when locking.

removed srcl mode hop offset
if PRMI ASC flags are false, the guardian returns true (doesn't check for ASC convergence), we should also do this for DRMI ASC
changed PRMI to DRMI transition to just zero gains for MICH and PRCL

***

Jenne and I attempted to check the PRCL/SRCL decoupling in the LSC matrix, and measured a value by injecting a PRCL line into reflair 9 and 45. However, the resulting OLGs looked even worse. Both PRCL and MICH look very strange, possibly indicating cross coupling. Unfortunately I don't have images of the PRCL transfer function but here is the MICH tf.

Seems like the phasing is wrong, but the loops became more unstable when we reverted the phasing changes I made earlier.

SUS

Images attached to this report

H1 General - Wednesday OPS EVE Shift Start

anthony.sanchez@ligo.org — Wed, 09 Sep 2026 16:50:31 -0700

Author: anthony.sanchez@ligo.org

Report ID: 91857

TITLE: 09/09 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 16mph Gusts, 9mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.11 μm/s
QUICK SUMMARY:
The Comissioners are Working on DRMI alignment and Locking seems like H1 is going through Green Arms and IR just fine.
VAC Team is currently working on HAM7 valving.

LHO General - Wed DAY Ops Summary

corey.gray@ligo.org — Wed, 09 Sep 2026 16:40:32 -0700

Author: corey.gray@ligo.org

Report ID: 91844

TITLE: 09/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Tony
SHIFT SUMMARY:

H1 Commissioning continued with relatively stable PRMI locks + 2-DRMI locks, and continued locking work (i.e. alignment tweaks, Length to Pit decoupling measurements, BS satamp whitening change, rfpd phasing, checking pointing on REFL A/B)

Relay Tube install started late morning with disassembly on HAM5 and then pumping down the Relay Tube (Gate Valves on both sides of the Relay Tube will remain CLOSED). Relay Tube leak checked (no leaks observed, VAC will turn OFF Mega-cleanroom at end of day)

BBSS had a satamp change to address
LOG:

1522 Jenne started on H1 to get to PRMI locking...
- Green Arms Manual: Green arms weren't locking, so Jenne touched up both arms by hand and they eventually locked to progress to Locking ALS; then they went to CHECK IR
- Had a 10min PRMI while they were running L to G coupling measurements
- During Relay Tube work, Elenna ran OLG measurements
1712-1856 Relay Tube install, pump-down, & leak check (jordan, gerardo, travis)
- --> Pumping down and maybe leak check tonight or tomorrow <--
1728-1847 Alog down for mainteance! (nyath)
1807-2012 BBSS satamp chassis change (fil)
- 2000-2012 investigating change with oli & going out to rack
1813-1847 Taking photos of Dustmon pumps at EX
1855-1935 EX & EY glycol fill for HVAC chillers (eric)
1900-2000 JAC measurements (jennie)
1958 Vendor visit #1 (for VAC team)
2119-2142 Leak checking Relay Tube (jordan, gerardo)
- No leaks for Relay Tube; Mega-Cleanroom lights turned OFF, but will turn OFF Mega-Cleanroom fans at the end of the day (to minimize temperature changes for commissioners)
2119-2143 EX switching off Turbo Station (travis)
21:42:34 Lights flickered in control room
2151 Vendor visit #2 (for VAC team)
2159 Checking alignment on REFL A/B PD on ISCT1 (sheila)
- clicking LVEA Local on Reservation System
2224 sorting old tcs property for removal along the X-Beam Manifold (tj)
2235-2333 VAC trip to EY with vendor.

H1 IOO - Comment to Calibration of JAC error signal into m

jennifer.wright@ligo.org — Wed, 09 Sep 2026 14:56:36 -0700

Author: jennifer.wright@ligo.org

Report ID: 91856

After discussing with Masayuki he reminded me that the JAC is less stable a reference than the IMC as it is not a suspended cavity. So we should use the IMC length noise as our SPI reference.

H1 IOO - Repeating actuator calibration measurements for IMC mirrors

jennifer.wright@ligo.org — Wed, 09 Sep 2026 14:44:52 -0700

Author: jennifer.wright@ligo.org

Report ID: 91854

I tried to repeat Masayuki's measurement in this alog to calibrate the JM3, MC1, MC2 and MC3 angular motion into uradians using the IMC cavity transmission, see this alog #91487.

This injects a line in turn on each steering mirror in pitch and yaw and looks for the height of the second harmonic of this line in the IMC transmitted power, as this should depend only on the size of the dither we apply to the alignment and not any existing static mis-alignment.

First I paused the IMC lock guardian and then turned off the IMC WFS (take gain to 0).

I then injected a line on JM3 pitch, then JM3 yaw. There were both at 30 counts into H1:SUS-JM3_M1_TEST_P_EXC and H1:SUS-JM3_M1_TEST_Y_EXC respectively.

The 2f line is viisble at 22 Hz as seen in the transmitted power ASD for the pitch excitation and the yaw excitation.

I then tried to do the same for MC1. I used 17Hz as my dither frequency and checked this didn't overlap with any modes of the MC1 mirror by checking the DAMP filter bank.

I could not get good measurement coherence at 34Hz with a 30 count excitation, when I went up to 60 counts the cavity unlocked, so I turned off the excitation, unpaused the guardian and brought the mode cleaner to down.

This plot shows the ASD during the 30 count injection with the red lines marking the 1f and 2f lines.

Looking back at the ndscope for the time when I thought the IMC unlocked (the mc trans camera spot flashed), it looks like the cavity did not unlock completely but started oscillating at 1Hz.

The first cursor is when the cavity lock started oscillating and the transmitted signal on IMC-TRANS PD went from 11000 counts to 6700 counts. When I turned off the excitation it went back up to the locked level again.

Second cursor is where I purposely brought the mode cleaner to down and the IMC TRANS PD went to 4000 counts.

Summary: I can use a dither on JM3 to measure the calibration of this mirror but to measure the MC mirrors I need to tune my excitation more precisely.

Images attached to this report

H1 SUS - Comment to BBSS M1 QOSEM satamp whitening modified (again)

filiberto.clara@ligo.org — Wed, 09 Sep 2026 14:32:05 -0700

Author: filiberto.clara@ligo.org

Report ID: 91855

WP 13597

Few things to note from LLO's alog 81756:

1. Chassis should be powered off at least 30 minutes before removing. This is to allow capacitors to discharge.
2. It takes over 45 minutes for the QOSEM signals to settle.

H1 SUS - BBSS M1 QOSEM satamp whitening modified (again)

oli.patane@ligo.org — Wed, 09 Sep 2026 13:38:27 -0700

Author: oli.patane@ligo.org

Report ID: 91853

Fil, Oli

Fil went ahead and did another modification to the BBSS M1 QOSEM satamp. This is the same modification that LLO had done (LLO:82137) - on each of the six boards, resistors R902, R1002, R1102, R903, R1003, and R1103 were swapped from 499kOhm to 22kOhm resistors.

Before the modification the satamp whitening was zpk([0.0144],[2.89],1), with compensation filter zpk([2.89],[0.0144],1). Changing these resistors has shifted the whitening zero up in frequency so the satamp whitening is now zpk([0.263],[2.89],1), with the new compensation filter zpk([2.89],[0.263],1). I have updated the whitening compensation filters ( BS_M1_OSEMINF_{F1,F2,F3,LF,RT,SD}_{SUM,X_RAW,Y_RAW} ) in OSEMINF to these new compensation filters.

Before we brought the BBSS back up we noticed that the SUM counts for F1 were railed, and that the SUMs for all other osems were between 18-20k counts. This is with the sum feedback on. When we turned the sum feedback off and just sent a constant current to the LEDs, F1 was still railed, but the other osems all jumped to normal varying SUM values that we had seen months ago prior to turning the sum feedback on - F3 and RT were staturating (like they had been doing back then), and the others were around 30k counts. Switching back to the sum feedback mode, we have been seeing the SUM counts all (except F1) climbing up slowly, and will hopefully stop in their nominal feedback on locations. We aren't sure why F1 is showing the counts as saturated though while in sum feedback mode - it hadn't been saturated before, and either way, turning on sum feedback mode should lower the current to the LED to lower the counts to a reasonable level (between 29k and 30k counts).

H1 PSL - PSL Status Report - Weekly FAMIS

anthony.sanchez@ligo.org — Wed, 09 Sep 2026 13:23:59 -0700

Author: anthony.sanchez@ligo.org

Report ID: 91852

PSL Status Report - Weekly FAMIS 64006

Laser Status:
NPRO output power is 1.86W
AMP1 output power is 70.67W
AMP2 output power is 139.5W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN

PMC:
It has been locked 14 days, 3 hr 2 minutes
Reflected power = 28.44W
Transmitted power = 104.6W
PowerSum = 133.0W

FSS:
It has been locked for 0 days 0 hr and 18 min
TPD[V] = 0.4517V

ISS:
The diffracted power is around 4.4%
Last saturation event was 0 days 4 hours and 22 minutes ago

Possible Issues:
PMC reflected power is high

H1 ISC - JAC 809Hz length dither is seen in JAC REFL camera on IOT1.

keita.kawabe@ligo.org — Wed, 09 Sep 2026 13:18:13 -0700

Author: keita.kawabe@ligo.org

Report ID: 91851

JAC REFL beam seems to be flickering in the video because the 809Hz length dither frequency is close to the integer multiple of the video refresh rate. I disabled the 809Hz length dither momentarily and the flickering was gone, see the attached video.

If we can see the effect of the dither just by using the video like this, the length dither amplitude is probably too large to enable in observing. One omega peak observed by ISS array is huge.

IOO, ISC

Images attached to this report

Non-image files attached to this report

PXL_20260909_185236980TS~2.mp4

H1 ISC - Comment to Revisit of the BBSS damping loop and some notes about issues from big kicks

elenna.capote@ligo.org — Wed, 09 Sep 2026 09:09:05 -0700

Author: elenna.capote@ligo.org

Report ID: 91849

Sheila notes that the big kicks in MICH dark were because although ETMY was marked as "misaligned" by the guardian, it was not actually misaligned, 91842. So that mystery is solved. We still need to come up with a strategy to handle the times the beamsplitter does get kicked, though.

H1 CDS - Comment to CDS Maintenance Summary: Tuesday 8th September 2026

david.barker@ligo.org — Wed, 09 Sep 2026 08:30:01 -0700

Author: david.barker@ligo.org

Report ID: 91848

We noted that h1oaf0's 6th ADC (ADC5) had failed its AUTOCAL. Trending shows this has been the case for at least 9 months.

LHO FMCS - HVAC Fan Vibrometers FAMIS Check (FAMIS 62540)

corey.gray@ligo.org — Wed, 09 Sep 2026 08:12:45 -0700

Author: corey.gray@ligo.org

Report ID: 91847

For FAMIS #62540: All fan trends look fairly flat (even after the step-down 5-days ago which Tony notes in alog 91811).

PEM

Images attached to this report

LHO General - Comment to Wed DAY Ops Transition

corey.gray@ligo.org — Wed, 09 Sep 2026 08:03:27 -0700

Author: corey.gray@ligo.org

Report ID: 91846

Reran launch script for nuc25 to bring up the DRMI FOM Displacements dtt.

H1 PSL - PSL Status Report (FAMIS #64007)

corey.gray@ligo.org — Wed, 09 Sep 2026 07:53:14 -0700

Author: corey.gray@ligo.org

Report ID: 91845

This is for FAMIS #64007.
Laser Status:
NPRO output power is 1.846W
AMP1 output power is 70.55W
AMP2 output power is 139.4W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN

PMC:
It has been locked 13 days, 21 hr 33 minutes
Reflected power = 28.32W
Transmitted power = 104.6W
PowerSum = 132.9W

FSS:
It has been locked for 0 days 9 hr and 2 min
TPD[V] = 0.4572V

ISS:
The diffracted power is around 4.3%
Last saturation event was 0 days 9 hours and 52 minutes ago

Possible Issues:
PMC reflected power is high

PSL

LHO General - Wed DAY Ops Transition

corey.gray@ligo.org — Wed, 09 Sep 2026 07:41:07 -0700

Author: corey.gray@ligo.org

Report ID: 91843

TITLE: 09/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 5mph Gusts, 2mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.13 μm/s
QUICK SUMMARY:

Looks like great progress yesterday with X-arm opened and locking green arms. This morning ISC LOCK is at Prep For Locking, there were multiple dust alarms, and all is fairly quiet otherwise.

H1 ISC - Comment to We can lock ALSX with slow controls and wfs to ETMX

sheila.dwyer@ligo.org — Tue, 08 Sep 2026 22:46:22 -0700

Author: sheila.dwyer@ligo.org

Report ID: 91842

I set the flags in lscparams, gate_valve_flag = False, and no_ETMX_actuation to False.

ALS COMM and DIFF locked without any issue (except some guardian typos we introduced with our new flag), and I stepped manually through some initial alignment steps manually adjusting alignments and usuaing the guardian to lock cavities.

The AS 45 error signal for MICH dark didn't look right, this was because ETMY test offsets were off, even though the guardian state said it was misaligned. There was a message on the suspension overview screen saying test offsets are off. I'm not sure why this happened, or if we can make the way the guardian handles this less confusing. X arm IR, PRX, SRY had no issues.

Locked ALS again, COMM had to do the full search to find IR, I updated the last value in the list with the found location.

In PRMI POP18 flashes up to 150 counts, (I_ERR_DQ channel). I accidentally kicked the BS when I added a yaw element to the new BS damping matrix we added this morning (91834).

PRMI did not lock quickly, we may need to undo some of the changes in 91530 and 91501 now that we have the arms back.

H1 ISC - We can lock ALSX with slow controls and wfs to ETMX

elenna.capote@ligo.org — Tue, 08 Sep 2026 20:40:03 -0700

Author: elenna.capote@ligo.org

Report ID: 91841

Camilla, Ryan S, Louis, TJ, Elenna

After GV20 was opened, we were able to successfully lock the X arm on green and send both slow control and green WFS control to ETMX!

We have rerun the baffle scripts for TMSX, ITMX, TMSY and ITMY. We have locked both arms on green, ran the green wfs, and ran through ETM_TMS_WFS_OFFLOADED. Then, we used these positions of the ITMs to set the green camera offsets. This means we can now full run the green arms initial alignment state, and no longer need to run baffle pd scripts to position the ITMs.

Camilla, TJ, Ryan and Louis worked to run the baffle scripts. They had some difficulties with ITMY because it seems to have started in a weird place, but Camilla moved ITMY around by hand enough that she was able to get the script to run properly.

From there, locking the green arms was straightforward, and there were no issues. I've attached the SDF screenshots of the new green camera offsets.

Reminder of how to do this:

ensure ITM alignment positions are set how you want them (either through baffle pd scripts, or full IFO alignment convergence)
go to END X/Y OVERVIEW and click CAM ITM PIT/YAW button to open the green camera offset screen (I included an example screenshot of the ITMX screen for reference)
take a 30 second average of H1:ALS-{X,Y}_CAM_ITM_{PIT,YAW}_POS channels, this is the channel next to "position", this can be done as 'z avg 30 [channel name]'
put that result in the "nominal" entry below "position"
SDF
Once this is set, full initial alignment should be run!

Images attached to this report

LHO VE - BSC9 Leak Check Done

gerardo.moreno@ligo.org — Tue, 08 Sep 2026 19:04:32 -0700

Author: gerardo.moreno@ligo.org

Report ID: 91840

(Jordan V., Travis S., Gerardo M.)
Transported all the equipment to X-End this morning, leak detector and helium in a small bottle. Connected the leak detector to the main turbo pump and left the leak detector pumping for some time to warm up. Isolated the X-End large ion pump from the main volume. Tested the small Conflat by spraying it with helium, this CF blank is installed on the TMDS injection port of BSC9 -Y door. The leak detector registered a background of 2.0x10^-10 Torr*l/Sec, no leak was detected by the leak detector. The leak detector was decoupled from the main turbo pump and the isolation valve was opened for large ion pump. At this point we collected all items, 2 ISP-1000, 1 electrical bang box, and 1 leak detector, all were transported back to the corner station.

We noted that when we isolated the main ion pump for X-End the pressure dropped at the X-End main vacuum volume, and once we opened the isolation valve the pressure at the X-End main vacuum volume went up, head scratching, perhaps the ion pump is not as effective any more. Also, the background at the leak detector was different, with the ion pump part of the volume the background was at 2.0x10^-10 Torr*l/Sec, without the ion pump the background was very low, <1.0x10^-12 Torr*l/Sec. No RGA data available of this station, no remote connection to it was possible, and to do that locally it takes some time to setup, and we did not want to delay the GV20 opening more.

Images attached to this report

H1 CDS - Comment to CDS Maintenance Summary: Tuesday 8th September 2026

ezekiel.dohmen@ligo.org — Tue, 08 Sep 2026 17:30:37 -0700

Author: ezekiel.dohmen@ligo.org

Report ID: 91839

BIOS setting changed, now matching the LIGO-T1300430 document:

CPU C State Control :
Enhanced Halt State (C1E) : Enabled -> Disabled

Package C State Control:
Package C State : Auto -> C0/C1 state

H1 ISC - Revisit of the BBSS damping loop and some notes about issues from big kicks

elenna.capote@ligo.org — Tue, 08 Sep 2026 17:21:55 -0700

Author: elenna.capote@ligo.org

Report ID: 91837

Sheila suggested we adjust the top mass damping to improve the step response, 91808. I created a 20 Hz elliptical low pass so we could raise the gain even further. However, this has little effect on the 0.45 Hz ringing in the step response, because this is not coming from the top mass. This is evident in the OLTFs, see pitch below. There could be cross coupling with length, but more likely this is some pitch mode between the lower stages that is not witnessed in the top mass osems. Therefore, damping it will have to occur with a lower stage damping loop using the oplev or M3 wit.

As it stands, we're getting plenty of suppression in LPY with the top mass damping. With the updated model, 91834, we can revisit lower stage damping.

***

I wanted to add some details about a challenge we are having with the beamsplitter. In short, if the BBSS is kicked a large amount, this saturates the QOSEMs to the point that the top mass damping loops cannot be used, and we have to put the beamsplitter in safe until the suspension freely damps enough that we can reengage damping.

This happened four times today, and has happened at least twice before. The first time occured today because I was adjusting damping gains and put a gain that was so large it rung up the loop. It took about 10-15 minutes to damp down. This kick also trips the ISI.

The other three times occurred today while we were trying to lock MICH dark during initial alignment. I had put the beamsplitter into what I thought was a decent enough alignment to lock MICH dark- clearly it was not because the MICH loop engagement kicked the beamsplitter significantly. I tried twice more after touching up the alignment further and the same problem occurred. From a quick glance, it looks like the MICH and BS lock settings were correct, but I with carefully check tomorrow one more time before we try this again.

Images attached to this report

H1 CDS - ETMX HV Power Supplies & Ring Heater

filiberto.clara@ligo.org — Tue, 08 Sep 2026 17:17:53 -0700

Author: filiberto.clara@ligo.org

Report ID: 91838

WP 13594

The EX ESD HV power supplies and ring heater chassis were powered ON this afternoon.

TCS

H1 CDS - CDS Maintenance Summary: Tuesday 8th September 2026

david.barker@ligo.org — Tue, 08 Sep 2026 16:59:18 -0700

Author: david.barker@ligo.org

Report ID: 91836

WP13584,13585 Add 7th ADC to h1oaf0 IO Chassis, add to models

Erik, EJ, Jonathan, Fil, Dave:

A 7th ADC was added to h1oaf0's IO Chassis. Because all the cards in this chassis had been shifted left by one slot to move the 20bit-DAC from A1-4 to A2-1, there was only one slot ADC6 could go into, A3-4.

Erik and EJ took the opportunity of powering h1oaf0 to check the BIOS settings (some needed changing), performing Adnaco benchmark tests, and disconnecting A4 from the computer.

Fil installed the new AA chassis for ADC6, it currently does not have anything connected to its inputs.

Dave made h1iopoaf0 and h1pemcs model changes. PEM reads out all 32 channels of ADC6 into filtermodules H1:PEM-CS_ADC_6_[0-31]. These FMs have been turned on.

DAQ restart was required for the model changes.

WP13591 h1susbs add M3 matrix

Sheila, Ellena, Dave

A new h1susbs model was installed. A DAQ restart was required

WP13592 h1crsproc add BLRMS

Jim, Erik, EJ, Dave

A new h1crsproc model was installed. A DAQ restart was required

Note that the svn server redoubt was not available for a rev-lock build, so we did a "old fashioned" install

> rtcds build h1crsproc

> INSTALL_ONLY_REV_LOCKED=false rtcds install h1crsproc

DAQ Restart

Jonathan, Dave:

After the round of model restarts the DAQ was restarted; 0-leg followed by 1-leg. No EDC restart was required.

All framewriters rode through the restarts with no issues.

LHO General - Ops Day Shift End

thomas.shaffer@ligo.org — Tue, 08 Sep 2026 16:30:03 -0700

Author: thomas.shaffer@ligo.org

Report ID: 91835

TITLE: 09/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: Maintenance morning with the ETMX suspension also getting cleared of rubbing (91833). This lead to opening the EX gate valve and we are now aligning the IFO.

Maintenance items of note:
- susbs (91834), crsproc, oaf model restarts and DAQ restart
- oaf1 ADC card added
- PEM ADC card and AA chassis install - 91832
- Troubleshooting transformer at EX
- EX leak checking

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:08	FAC	Kim	EY	n	Tech clean	15:59
15:20	-	Gabriele, guest	LVEA	n	Tour	15:47
15:48	FAC	Eric	EX	n	Transformer troubleshooting	16:37
16:00	FAC	Kim	EX, FCES	n	Garbage collecting	17:10
16:42	VAC	Gerardo, Jordan	EX	n	Leak checking setup, then leak checking	19:06
16:48	TCS	Camilla	Opt Lab	n	Getting old data from nanoscan	17:10
17:07	SUS	Oli	CR/EX	n	SUS health checks	18:07
17:34	CDS	Fil, Erik	CER, MSR	n	OAF0 AA & ADC swap	18:14
17:55	FAC	Kim	LVEA	n	Tech clean	18:56
17:58	CDS	Dave	Remote	n	SUS BS, CRS proc, model restarts and then DAq restart	18:14
17:59	FAC	Chris	LVEA	n	Safety item checks	19:13
18:35	GC	Nyath	Desk	n	Alog and SVN disk migration	21:47
18:38	SEI	Jim	CER	n	Swap HAM3 interface chassis	18:53
21:21	VAC	Jordan	LVEA	n	HAM7 RGA scan	22:03
21:39	SEI	Jim	CER	n	Swapping HAM3 interface chassis back	21:53
22:25	VAC	Jordan, Gerardo, Travis	EX	n	Opening GV20	23:18
22:58	CDS	Fil	EX	n	Turning on HV	23:24
23:19	TCS	Camilla	LVEA	n	Turning on CO2 lasers	23:24

H1 SUS - BBSS model change

elenna.capote@ligo.org — Tue, 08 Sep 2026 15:33:58 -0700

Author: elenna.capote@ligo.org

Report ID: 91834

Sheila, Oli, Elenna

Today we made a change in the BBSS model (ECR E2600297) to create a matrix in the BBSS OLDAMP on M2 and M3 that allows switching between the BBSS oplev and the BBSS M3 wits as the sensor. Sheila determined that the M3 wits have better SNR than the oplev, and may also have less cross coupling between pitch and yaw.

Right now we send oplev damp feedback to M2, but we have the infrastructure to damp on M3.

Sheila estimates that the gain shoiuld be reduced by about a factor of 3 if the M3 wits are used as a sensor instead of the oplevs.

H1 SUS - ETMX still looking good!

oli.patane@ligo.org — Tue, 08 Sep 2026 13:57:00 -0700

Author: oli.patane@ligo.org

Report ID: 91833

ETMX is still looking good and there's no rubbing seen. I've taken transfer functions for M0 and R0 this morning with everything in its nominal state (ISI floating, very in vacuum) (except OPTICALIGN OFFSET sliders OFF).

Settings:
- ETMX in HEALTH_CHECK
- DAMP OFF
- ALIGNMENT OFFSETS OFF
- In VAC
- HPI/ISI nominal

Comparison Results:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/allquads_2026-09-08_ETMXRubbingCheck_ALL_TFs.pdf /ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/allquads_2026-09-08_ETMXRubbingCheck_ALLM0_TFs.pdf /ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/allquads_2026-09-08_ETMXRubbingCheck_ALLR0_TFs.pdf

/ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/allquads_2026-09-08_ETMXRubbingCheck_ALL_ZOOMED_TFs.pdf /ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/allquads_2026-09-08_ETMXRubbingCheck_ALLM0_ZOOMED_TFs.pdf /ligo/svncommon/SusSVN/sus/trunk/QUAD/Common/Data/allquads_2026-09-08_ETMXRubbingCheck_ALLR0_ZOOMED_TFs.pdf r13142

M0
Data:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGM0/Data/2026-09-08_1600_H1SUSETMX_M0_WhiteNoise_{L,T,V,R,P,Y}_0p01to50Hz.xml r13141
Results:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGM0/Results/2026-09-08_1600_H1SUSETMX_M0_ALL_TFs.pdf r13141

R0
Data:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGR0/Data/2026-09-08_1715_H1SUSETMX_R0_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml r13140
Results:
/ligo/svncommon/SusSVN/sus/trunk/QUAD/H1/ETMX/SAGR0/Results/2026-09-08_1715_H1SUSETMX_R0_ALL_TFs.pdf
r13140

Images attached to this report

Non-image files attached to this report

allquads_2026-09-08_ETMXRubbingCheck_ALL_TFs.pdf

allquads_2026-09-08_ETMXRubbingCheck_ALLM0_TFs.pdf

allquads_2026-09-08_ETMXRubbingCheck_ALLR0_TFs.pdf

allquads_2026-09-08_ETMXRubbingCheck_ALL_ZOOMED_TFs.pdf

allquads_2026-09-08_ETMXRubbingCheck_ALLM0_ZOOMED_TFs.pdf

allquads_2026-09-08_ETMXRubbingCheck_ALLR0_ZOOMED_TFs.pdf

2026-09-08_1600_H1SUSETMX_M0_ALL_TFs.pdf

2026-09-08_1715_H1SUSETMX_R0_ALL_TFs.pdf

H1 CDS - PEM AA Chassis and ADC Installed

filiberto.clara@ligo.org — Tue, 08 Sep 2026 11:23:38 -0700

Author: filiberto.clara@ligo.org

Report ID: 91832

WP 13585
WP 13584

A PEM AA 2U chassis was installed in the PEM/OAF rack (slots U24, U25) in the CER. A general standards ADC card, ribbon cable and interface card were installed in the PEM/OAF/TCS IO chassis.

PEM AA - SN S2300114
ADC Card - SN 211109-05
ADC Interface Card - SN S1102352

Had difficult time installing the AA chassis with tempoary in-rack cabling obstructing access to the rack. Traced cabling to LVEA and disconnected 7 used cables in the SUS-R3 PEM patch panel. Cables are part of old seismometer huddle test and newtonian noise test.Cabling in the CER was also removed.

D. Barker, F. Clara, E. Von Reis

PEM

H1 SUS - Reapted Alignment Slider Step Responce for ITMX

camilla.compton@ligo.org — Tue, 08 Sep 2026 11:22:07 -0700

Author: camilla.compton@ligo.org

Report ID: 91830

As Sheila did for the BS in 91808. Both times the alignment slider filters had a TRAMP of 2s. This doesn't look too different from the BS Yaw steps but the alignment slider steps in BS Pitch ring a lot longer than all ITMX steps.

There is ringing but it damps a lot quicker than the BS Pitch steps ringing, back to normal noise levels in 15-20seconds. The BS ringing seemed to damp in 40-50s for Pitch but 15s for Yaw.

slider	10urad P on ITMX	10urad Y on ITMX
M0 damp in1	22 urad P (no Y step)	8 urad Y (0.5 urad P step)
L1 WIT	8.8 urad P (-0.2 urad Y)	5.5 urad Y (no step in P)
M3 oplev	2.5urad P (0.15 urad Y) 0.45Hz ringing starts 2.3 urad p-p, gone in 20s	2.3 urad Y (0.4urad P) 0.6Hz ringing starts 0.6 urad p-p, gone in 15s

ISC

Images attached to this report

H1 PSL - PSL Cooling Water pH Test - Monthly

ryan.short@ligo.org — Tue, 08 Sep 2026 11:05:11 -0700

Author: ryan.short@ligo.org

Report ID: 91831

FAMIS 63882

pH of PSL chiller water was measured to be between 10.0 and 10.5 according to the color of the test strip.

H1 PSL - PSL 10-Day Trends

ryan.short@ligo.org — Tue, 08 Sep 2026 10:41:57 -0700

Author: ryan.short@ligo.org

Report ID: 91829

FAMIS 63915

No major events of note, things are running smoothly. Some channels flatlined over a week ago due to a network switch going down, but this had no effect on the performance of the system.

Images attached to this report

LHO VE - Comment to Vacuum Recovery From TMDS Work at X-End

jon.feicht@ligo.org — Tue, 08 Sep 2026 09:15:14 -0700

Author: jon.feicht@ligo.org

Report ID: 91828

Should we try to incorporate a phase rotation monitor/relay somewhere in the chain?

LHO FMCS - Comment to Using Vibration Sensors To Gauge Health Of HVAC Fans.

thomas.shaffer@ligo.org — Tue, 08 Sep 2026 08:04:52 -0700

Author: thomas.shaffer@ligo.org

Report ID: 91827

Tagging FMCS

H1 CDS - Workstations updated

erik.vonreis@ligo.org — Tue, 08 Sep 2026 07:58:54 -0700

Author: erik.vonreis@ligo.org

Report ID: 91826

Workstations were updated and rebooted. This was an OS packages update. Conda packages were not updated.

LHO General - Ops Day Shift Start

thomas.shaffer@ligo.org — Tue, 08 Sep 2026 07:35:28 -0700

Author: thomas.shaffer@ligo.org

Report ID: 91825

TITLE: 09/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 2mph Gusts, 0mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.16 μm/s
QUICK SUMMARY: EX is pumping down after a successful TMDS'ing last week, we are down to 3e-9Torr. No alarms, all looks good for a light maintenance Tuesday.

H1 TCS - Using temporary 532nm laser to verify EX HWS design, and observe in-vacuum effects

madison.simmonds@ligo.org — Sun, 06 Sep 2026 21:40:28 -0700

Author: madison.simmonds@ligo.org

Report ID: 91248

Madi, TJ, Camilla

This work is a continuation and analysis of the measurements taken 90848, where the HWS lens chain was redesigned so that the 532nm OzOptic laser beam matched the ALS beam at M11 ie the PBS (ALS beam measurements 90370). The goal is to verify lens design methods, as well as get another measurement of the 'badness' affecting the beam in-vacuum.

Measurements were taken of the beam coming out of the OzOptic 532nm source before installation, to verify beam quality and identify location of the waist for further q-parameter calculations (see attachment). Measurements of the beam once it had traversed the new HWS path was then made after the PBS (and through a test-lens in order to make the beam small enough to be viewed by the Nanoscan head). These two sets of measurements were then extrapolated through a model of the (new) HWS on-table path, using ray transfer matrix methods.

An initial discrepancy between these two traces prompted measuring of the focal lengths of the lenses, which confirmed their nominal values, and re-measuring of the location of all components on-table, compiled 91241.

With the updated on-table locations, the two measurements and the model are in agreement (see attachment).

With confidence the beam before entering the vacuum has been characterised, the current knowledge of the in-vacuum optics is used as a model. The return beam was measured and compared to the output of the model. These results (Plot 1)(Plot 2) demonstrate that the knowledge of the EX in-vacuum optics is correct, evidenced by the trace extrapolated through the model coinciding with the measurements made of the return beam.

The return beam of the OzOptic laser also demonstrates similar double-lobed features to that observed on the ALS return beam (see attachment)

Images attached to this report

H1 SPI - Comment to SPI L Wrapped Phase Excursions on 2026-08-26 @ 17:16 UTC -- Probably Excitation

shreevathsa.chalathadka-subrahmanya@ligo.org — Sun, 06 Sep 2026 00:29:20 -0700

Author: shreevathsa.chalathadka-subrahmanya@ligo.org

Report ID: 91824

As suggested, I examined the ref and meas input power levels, as well as the contrast for all 4 interferometers. The attached plot clearly shows that during the two identified time intervals, the input power was disturbed, leading to the observed phase excursions. I haven't checked further to find out the reason for these power glitches. To rule out the possibility of something going wrong in the SPI laser prep chassis, we can look at the PSL side where the input laser gets fiber coupled. I am not sure about the availability of a power monitoring PD there or any other channel of interest.

[Update] Out of curiosity, I took a look at the IMC input power, hoping that it would give some hints if the corresponding glitches are present at the pick-off from ALS to SPI itself. The attached plot, clearly shows the anomalies matching with our phase excursions.

Images attached to this report