Fil, Camilla, Sheila. WP#12784

In 86323 we noticed a high pitched noise in SQZT7. Today we found the SQZT7 picos were enabled. When Sheila disabled them, the noise disappeared. It did not come back when they were re-enabled. 

All picos should be off in Obserivng so I monitored the sdf. However, even when enabled, the picos should not make this noise. Fil suggests we watch this pico controller closely as when used it it might intermittently get stuck trying to drive and start to make this noise again. 

Tagging DetChar:  this pico has been on in Observing from 24th June until 2nd September.

We made it up to NLN at 1941UTC but this only lasted 39 seconds before an ETMX glitch took us out. On the way back up we noticed that it would need to go through PRMI, so Elenna took the time to fix it since we ran into some issues with it last week (alog86618). We wrapped up a few SDFs that were left over from maintenance day activities, and then to observing at 2109 UTC.

After problems with PRC1 ASC, reported here, I checked the PRC1 P error signal and saw that the REFL signal seems to have a small offset. However, it appears that the POP X I signal has no offset, so I updated the error signal and tested the sign. The ISC DRMI code is updated with this new matrix.

Sheila, Matt, Camilla

As the interferometer stayed locked during the early part of maintence day, we did some injections into the filter cavity length to try to measure the noise caused by backscatter.  (Previous measurements 78579 and 78262, recent range drops that we think are filter cavity related: 86596)

The attached screenshot from Camilla shows the excitations and their appearance in DARM. (Compare to Naoki's measurement here, and to the time with no injection but elevated noise here).   I made a simple script to make the projection based on this injection, which is available here.  It does show about a factor of 3 a higher level of noise in DARM than Naoki's projection 78579, this is large enough that we should add it to our noise budget but far too small to explain our low range times last week.

• Dtt file is userapps/sqz/h1/Templates/dtt/filter_cavity/backscatter_20250825.xml
• reference 14-16 no excitation
• 17-18 amplitude 1000
• ref 20-22 amplitude 3000
• ref 23-25 amplitude 10000 start to see
• ref 26-28 amplitude 20000 pretty linear, maybe I unlocked FC

M. Todd

I did a sweep of the LVEA, everything looked fine.

I unplugged an extension cord from outside the PSL racks, and noted that a forklift by the 3IFO racks was left plugged it. I left it plugged in as it was.

Robert was still in there while I was doing my sweep, and he was notified that he was the last one.

TITLE: 09/02 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 5mph Gusts, 2mph 3min avg
    Primary useism: 0.30 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY: A bit delayed of a entry, but we are in maintenance mode. We stayed locked until 1627 UTC (927PT) before we were knocked out by some maintenance activities.

The FSS TPD has been slowly trending down again, so I did a quick remote adjustment of beam alignment into both the PMC and FSS RefCav today.

Starting with the PMC, I turned the ISS OFF, then adjusted the beam alignment from the Control Room using our picomotor mirrors.  Unfortunately, I did not get any improvement in either PMC Trans or PMC Refl.  PMC Refl has been very slowly increasing over the last couple of months, it may be time to take a look at adjusting the amplifier pump currents; we'll monitor this over the next week or two and move forward from there as necessary.  To end the PMC adjustments, I turned the ISS back ON.  It was diffracting ~4.2% (jumping between 4% and 4.5%), so I decreased the ISS RefSignal -1.99 V (from -1.98 V) to lower this a small bit.  The ISS diffracted power is now hanging around 3.8% (jumping between 3.6% and 4%); at this new diffracted power, PMC Trans is ~105.7 W.

Moving on to the FSS RefCav, with the IMC unlocked the TPD began at ~0.78 V.  I was able to get the TPD up to ~0.809 V, an OK improvement but not back where it was at the end of the last on-table alignment.  With the IMC locked the TPD is ~0.813 V.

Tue Sep 02 10:08:32 2025 INFO: Fill completed in 8min 29secs

Gerardo confirmed a good fill curbside.

No new issues found.

Rinse and repeat.

We tried staying locked through some of the maintenance activities and we made it pretty far. I had the SEI_ENV in Light Maintenance. There were people in the LVEA at the time, as well fork lifting into OSB receiving and maybe even some craning, so I'm unsure what actually knocked us out.

Test for Thursday morning at 7.45 am, assuming we are thermalised.

• In NLN.
• Turn off OMC ASC:
  • sitemap -> OMC -> OMC Control -> turn MASTER GAIN slider to 0 (its blue and on the bottom centre of screen).
• Run DARM offset step:
  • Go to /ligo/gitcommon/labtutils/darm_offset_step
  • run:

conda activate labutils

python auto_darm_offset_step.py

• Wait until program has finished ~20 mins.
• Turn OMC ASC back on by putting master gain slider back to 0.020.
• Heat up OM2 heater (~ 3 hours):
  • IFO out -> OM2 -> change H1:AWC-OM2_TSAMS_POWER_SET value to 4.6.
• After power has leveled out on H1:AWC-OM2_TSAMS_THERMISTOR_1_TEMPERATURE and H1:AWC-OM2_TSAMS_THERMISTOR_2_TEMPERATURE, turn off OMC ASC again by putting MASTER GAIN slider back to 0 on OMC Control screen.
• Run auto_darm_offset_step.py again.
• Put OM2 heater H1:AWC-OM2_TSAMS_POWER_SET back to 0.
• Test done, wait for thermistors to level out again.

[Fil, Erik]

Hardware watchdog at EX started count down when disconnected from either satellite amp.

TITLE: 09/02 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: One lockloss from the fire alarm, easy relock. We've been locked for just over 2 hours.
LOG: No log.

 There was a small LVEA temperature excursion from AHU2 not restarting after the fire alarm. It looks mostly leveled out now.

• 01:28 UTC lockloss
• 03:03 UTC Observing

01:30 UTC lockloss, the fire alarm went off. It was reported as a "trouble alarm, I called Richard and I then reset the alarm on the panel in the CUR.

TITLE: 09/01 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Observing at 153 Mpc and have been Locked for over 1.5 hours. Relocking after the lockloss today went fine besides needing to touch ALSX and ALSY a bit. Weirdly, the first two times ALSX locked and turned on WFS, after a bit the WFS pulled the alignment away and caused ALSX to unlock. I set everything up to be able to turn the WFS off for the next time, but then there was no problem.
LOG:

14:30 UTC Relocking and in DRMI_LOCKED_CHECK_ASC
15:09 NOMINAL_LOW_NOISE
    15:11 Observing
    18:59 Superevent S250901cb
    19:38 Earthquake mode activated - I moved us into earthquake mode because of some ground motion that USGS hadn't seen yet
    19:46 Back to CALM
20:07 Lockloss
    - ALSX and Y needed my help for locking
    - Twice ALSX WFS pulled ALSX away and unlocked it
21:54 NOMINAL_LOW_NOISE
    21:55 Observing

During the commissioning window this morning, I worked on the St0 to St1 feedforward for the HAM1 ISI. This time I borrowed some code from Huyen to try the RIFF frequency domain fitting package from Nikhil. This required using matlab 2023b which seems to have a lot of computationally heavy stuff like code suggestions added so it was kind of clunky to use and I'm not sure what all of the different fitting options do, so each dof took multiple rounds of fitting to get working. I also had to add an ac-coupling high pass after the fact to the filters because they all went to 1 at 0hz. Still the results I got for HAM1 seem to work pretty well. Attached spectra are the on-off data I collected for the X,Y and Z dofs. Refs are the ff off, live traces ff on spectra. Top of each image are the asds for the ff on & off, bottom is the magnitude of the st0 l4c to st1 gs13 tf. The improvement is broad ~10x less motion from 5 hz up to ~50hz. I'm looking at the rotational dofs still, but there is less coherence there, so not as much to win.

Elenna has said this seemed to have improved chard asc, maybe she has some plots to add.