TITLE: 06/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Somewhat uneventful day with just one lockloss that we're still trying to come back up from. H1 is relocking and currently up to LOCKING_ALS.

• 14:30 - Running auto initial alignment
• 14:45 - IA finished, starting lock acquisition
• 15:52 - Observing
• 16:27 - Dropped observing for SQZ fixes and ETMY roll mode damping
• 16:39 - Observing
• ~19:00 - Rode through M6.1 EQ from Japan
• 21:11 - Lockloss (alog85023)
• 21:32 - Starting lock acquisition after VAC team addresses pumps at HAM1
• 22:51 - Haven't been able to lock DRMI, cutting losses and starting initial alignment
• 23:07 - IA finished, starting lock acquisition

LOG:

Kiet and Sheila,

Following up on the investigation posted in aLOG 84136, we examined the impact of higher-order violin mode harmonics on the contamination region.

We found that subtracting the violin peaks near 1000 Hz (1st harmonic) from those near 1500 Hz (2nd harmonic) results in frequency differences that align with many of the narrow lines observed in the contamination region around 500 Hz.

Violin peaks that we used (using O4a+b run average spectra)

F_n1 = {1008.69472,1008.81764, 1007.99944,1005.10319,1005.40083} Hz 
F_n2 = {1472.77958,1466.18903,1465.59417,1468.58861, 1465.02333, 1486.36153, 1485.76708} Hz 

Out of the 35 possible difference pairs (one from each set), 27 matched known lines in the contamination region to within 1/1800 Hz (~0.56 mHz)—most within 0.1 mHz. Considering that each region actually contains >30 peaks, the number of matching pairs likely increases significantly, helping explain the dense forest of lines in the comtaimination region.

Next steps:

• Testing all the peaks in the 1st and 2nd harmonic region.
• We propose to identify lines with highest power in the contamination region, trace them back their source modes and discuss the feasibility of target damping them. 

The Fscan run average data are available here (interactive plots): 

Fundamental region (500 Hz): 

• 400–500 Hz
• 500–600 Hz

1st harmonic region (1000 Hz): 

• 900–1000 Hz
• 1000–1100 Hz

2nd harmonic region (1500 Hz): 

• 1400–1500 Hz
• 1500–1600 Hz

TITLE: 06/13 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 17mph Gusts, 11mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.12 μm/s
QUICK SUMMARY:

• 21:11 UTC lockloss, I ran a coherence measurement at ~5 hours in
• Windy.com forecasts the wind picking up around 04:00 - 05:00 UTC tonight
• We're currently running an IA as DRMI/PRMI has been having trouble locking

TCS Chiller Water Level Top-Off - BiWeekly FAMIS 27817

TSCY: Found at 10.4 and added 0
TSCX found at 30.3 and added 50mL
Everything looks like its functioning well.
 

Lockloss @ 21:11 UTC - link to lockloss tool

No obvious cause, but looks to have been sudden. We're taking advantage of the downtime to have the VAC team address pumps on HAM1.

Yesterday we ran a bruco on Francisco's post-vent SQZ time from 84996. Link to bruco here.

Command used: python -m bruco --ifo=H1 --channel=GDS-CALIB_STRAIN_CLEAN --gpsb=1433758866 --length=600 --outfs=4096 --fres=0.1 --dir=/home/camilla.compton/public_html/brucos/1433758866 --top=100 --webtop=20 --plot=html --nproc=20 --xlim=7:2000 --excluded=/home/elenna.capote/bruco-excluded/lho_DARM_excluded.txt

Links to to a few coherences, although I haven't done a deep dive: SRCL (some 100-250Hz), PRCL, MICH (bad 2-4Hz), PSL ISS 2nd loop, can see the jitter peaks in IMC WFS 

Closes FAMIS26392

For the CS fans, they look fine althought MR_FAN5_170_2 is a bit noisy.

For the OUT building fans, there's a periodic noise increase on a few different fans. EY_FAN2_470_2, EX_FAN1_570_{1,2} and MX_FAN2_370_1.

Summary of (our knowledge about) 2nd loop array units are available on DCC: https://dcc.ligo.org/LIGO-D1101059

We opened the container of S1202966 in the optics lab for inspection. This is a unit removed from LHAM2 in 2016.

We found no damage (1st picture), all photodiodes and the QPD look OK, no chipping of the optics, but many components are missing.

• Missing upgrade components to lift QPD higher to make it closer to the optical plane of the array photodiodes. We'll search for spares.
  • D1300718. This is a kit comprising two 4.501" poles with cutout, one 6.511" pole and two thinner 3" poles.
  • D1300719. This is called QPD MT PLATE, it's a top platform to mount the QPD as well as the ISS array cover assembly.
  • Related hardware.
• Missing upgrade components to tilt QPD. We have spare parts.
  • D1400146 Beveled C-bore Washer to tilt the QPD assy by 1.41deg to avoid direct reflection back. We have spares we can use.
  • D1300963-V2 updated QPD clamp plate to accomodate 1.41deg tilt. V1 doesn't work. We have spares we can use.
•  Missing extended ISS array cover/lid assembly parts (ECR https://dcc.ligo.org/LIGO-E1300662). We will search for spares.
  • D1300717 Array Cover (Extended). Unlike the name would make you believe, this is not the cover assembly, but is a kit comprising one each of 5 different panels i.e. D1300717-101, D1300717-102, D1300717-103, D1300717-104 and D1300717-105. 
    • At least 5 kits have been made according to ICS. We know of four kits used for existing arrays, i.e. two in the existing IFOs (one each at LHO and LLO), one in the optics lab for S1202965, and the last one for S1202967 that was bent and contaminated. Assuming that the 3IFO unit (S1202968) has the cover, we might not have a spare.
    • But the same ICS record also shows 5 pieces of mysterious (to me) D1300717-00, four of which are supposed to be at LHO. If D1300717-00 means the entire kit comprising 5 panels, we might have spares.
  • D1300890 Array Cover Corner Support. This is a kit of 3 different corner braces, i.e. 1 piece of D1300890-1, 2 pieces of -2 and 1 piece of -1. 
    • According to ICS we seem to have produced 9 kits. Like D1300717, we know four kits used for existing assemblies (H1, L1, S1202965, S1202967), and I assume that the 3IFO unit (S1202968) has one. So we should have four spares somewhere.

I decided to disassemble the damaged/contaminated S1202967 partially to send some of the parts to C&B and keep them as the last-resort spares. Jennie sent the following parts to C&B. There are deep scuffs which should be the result of repeated metal-to-metal contact/scratching, but they should be OK for use once they go through C&B.

• D1300718. A kit comprising two 4.501" poles with cutout, one 6.511" pole and two thinner 3" poles.
• D1300719. Top platform to mount the QPD as well as the ISS array cover assembly.
• Related hardware.

ISS array cover might be salvageable but the place where the poles are attached is bent so badly, bending it back might break it. See the 2nd picture, the surface is supposed to be flat.

Since we've been seeing the ETMY roll mode consistently ringing up over the start of lock stretches and that it can cause locklosses after long enough, Sheila modified the 'DAMP_BOUNCE' [502] state of ISC_LOCK to now engage damping of this mode with a gain of 40. The state has also been renamed to 'DAMP_BOUNCE_ROLL'. I have accepted the gain of 40 and timeramp of 5 sec in the OBSERVE.snap table of h1susetmy and only the timeramp in the SAFE.snap table (screenshots attached; we had originally set the gain at 30 but then updated it to 40, which I forgot to take a screenshot of).

We are still unsure as to why this roll mode has been ringing up since the vent, but so far Elenna has ruled out the SRCL feedforward and theorizes it could be from ASC, specifically CHARD_P (see alog84982 and comments).

Fri Jun 13 10:07:30 2025 INFO: Fill completed in 7min 27secs

Jordan confirmed a good fill curbside.

The squeezer ASC was misaligning the squeezer early in the lock as it has been doing this week. 

Ryan took us out of observing to deal with this and the roll mode. I went to no squeezing and reset the AS42 offsets for no squeezing, a little more than 1 hour after power up.  These offsets have changed with thermalization in the past. 

I reset the sqz ASC using the "graceful clear history".  Once the squeezing was injected the RF3 level was too low to lock, so I adjusted ZM6 manually. I could perhaps have done this (without reseting the offsets) by asking SQZ_MANAGER to RESET_SQZ_ASC, as Oli and Camilla suggested last night.

I accepted the offsets in the observe.snap, but forgot about the safe.snap.  Ryan verified that SQZASC is not included in SDF revert, so this will be fine for the weekend, but we should accept these in safe.snap sometime soon.

If we have another lock today we can see if reseting the offsets has helped with the asc issue during thermalization.  If we do not, we can set the flag to not run sqz ASC over the weekend.

WP12620

09:35 I started the copy of the past 6 months of raw minute trend files from h1daqtw0 to h1ldasgw0-RAID using h1daqfw0. This copy typically takes about 26 hours. It is running in nice mode to minimize its impact on daqd.

Fully automatic relock except for an unsurprising adjustment of PRM to lock DRMI.

Also accepted a batch of SDFs to start observing:

• MCL trigger thresholds (details in alog85012)
• ETMY roll mode damping filter ramptime

TITLE: 06/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 12mph Gusts, 5mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY: Looks like H1 unlocked at 14:00 and just finished up running an initial alignment. Starting lock acquisition now.

Received phone call at 1:20amPDT.

Saw that H1 was at NLN, and ready to go to Observing, but could not due to SDF Diffs for LSC & SUSETMY (see attached screenshot):

1) LSC

• H1:IMC-MCL_FM_TRIG_THRESH_ON at 100 (should be 1300)
• H1:IMC-MCL_FM_TRIG_THRESH_ON at 90 (should be 200)

I was not familiar with these channels, so I went through the exercise of trying to find their medm, but for the life of me I could not get there!  The closest I got was LSC Overview / IMC-MCL Filter Bank, but they were not on that medm.  (probably spent 30min looking everywhere and in between with no luck).   Looked at these channels in ndscope & these channels were at their nominals for the last lock.  Also looked in the alog, and only saw SDF entries for them from 2019 & 2020.  Ultimately, I just decided to do a REVERT (and luckily, H1 did not lose lock).

2) SUSETMY

• This was just a TRAMP, so I also REVERTed this.

Then H1 automatically went back to Observe.

Maybe Guardian, for some reason took these channels to these settings?  At any rate, going to try to go back to sleep since it has been an hour already (hopefully this does not happen for the next lock!).

TITLE: 06/13 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY:

Observing at 148 Mpc and have been Locked for almost 6 hours. I just turned the Roll damping off for ETMY so we don't get any sdf diffs if we have to relock overnight.

When we first got back up, we were noticing the ETMY roll mode ringing up again, which we had been hoping to have solved by Elenna's changes to the SRCL FF (84998). We tried turning damping back on where we had had it in previoius locks (at 20), but this didn't seem to be doing anything this time. We eventually tried a gain of 30 instead, and this finally started damping it.

Near the beginning of the lock, we also had the SQZer unlock and it was having trouble relocking by itself because the LO could not relock due to the ASC having pulling ZM4 and ZM6 out of range. To fix this, Camilla took us to NO_SQZ, then cleared the history on the P and Y lock filters on ZM4/6. Afterwards, she verified that we would've also been able to do this by just taking SQZ manager to RESET_SQZ_ASC, and then back to FDS once that finishes.

In the hours after that, we've had the SQZer unlock multiple times, which is why we've been popping in and out of Observing so much, but each time it has been able to relock itself fine.

LOG:

21:30 Working on PRMI
21:41 Decided to just try and relock bc wind is rising
    - Started an IA due to DRMI not being able to catch
    - Lost lock during ENGAGE_ASC_FOR_FULL_IFO (the glitch that happens during it got too big)
23:32 NOMINAL_LOW_NOISE
23:39 Observing
23:41 Quickly out of Observing to turn on ETMY Roll damping
23:41 Back into Observing
23:54 Out of Observing due to turning ETMY roll damping back on
23:54 Back into Observing
00:01 Out of Observing due to SQZer unlocking
    - LO could not relock due to the ASC running away
00:15 Back into Observing
00:17 Out of Observing to try bumping up the ETMY Roll damp gain
00:17 Back into Observing
02:17 Out of Observing due to SQZ unlock
02:20 Back into Observing
02:49 Out of Observing due to SQZ unlock
02:57 Back into Observing
03:37 Out of Observing due to SQZ unlock
03:38 Back into Observing
05:11 Out of Observing to turn the ETMY roll damping off
05:12 Back into Observing                                                                                                                                                                                                                                                                                                                                        

Observing at 145 Mpc and have been Locked for 4  hours. We've been bumped out of Observing a couple times due to SQZ unlocking, but it's been able to get everything back in order by itself each time.