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

TITLE: 02/11 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 158Mpc
INCOMING OPERATOR: Oli
SHIFT SUMMARY: The range has been fairly steady, we stayed locked all shift with 2 superevents.
LOG:

21:35 UTC Observing

02:26 UTC supervent S250211aa

04:36 UTC superevent S250211be

I took a look at the locklosses during the calibration measurements the past week. Looking at DARM right before the locklosses, both times a large feature grows around ~42 Hz right before the lockloss. Sat LL Thur LL

Thursday:

DARM_IN was dominated by the 42 Hz long oscillation and a ~505 short oscillation until the LL, DARM_OUT was dominated by the harmonic of the violins ~1020 Hz.

Saturday:

DARM_IN had a long and a short oscillation, the fund violin modes, ~510 Hz and ~7.5 Hz, DARM_OUT was dominated by the harmonic of the violins ~1020 Hz

I'm not sure how to/where to see exactly what frequencies the simulines were injecting during and before the lockloss.

To rebuild the spare ISS PD Array unit (D1101059 S1202967, note that I myself don't have an access right for the S-number document on DCC) and align the PDs, we opened the transport container (D1400368) in the optics lab.

We initially had a hard time to open the container as the viton gasket (D1400366) was REALLY firmly stuck to the container lid (D1400367) and the container base (D1400365). We put the container on top of small stainless steel cart and used screwdrivers to pry the cover off from the base plate. Even after two  corners were freed, we could not lift the lid just by hand, and we had to continue prying the lid until all four corners were freed.

Contamination:

After finally removing the lid, we found two bases for concern, the first is the contamination.

1. There were some class A hardwares (screws/bolts, washers, one half of the QPD PCB retainer, and what turned out to be one of the two adjustment cams for one of the two plate high reflectors) scattered around on the transport container base plate, which is supposed to be a class B surface. But the base plate was dirty when we wiped it using pre-soaked wipe.
2. Another half of the QPD PCB retainer was freely lying on the ISS PD base plate (D1300323) which is supposed to be class A surface, and it was dirty too.
3. We wiped all parts that were not attached to anything, and they were all dirty.
4. We haven't assessed the quality of the diodes nor the plate optics but there's no reason to believe that they are not contaminated.

The first two pictures shows the container assembly before and after removing the lid. 

Note that the second picture shows the class A "cover" for the assembly tilted back. It turns that the cover was just put there, free to rattle. Connection rods that are supposed to attach the cover to the cage structure were not bolted to the cage.

The third picture shows how filthy the container base plate was. It also shows a half of QPD retainer parts that were found there, next to a swagelock fitting attached to the base plate.

Fourth picture shows the pre-soaked wipe I used to lightly clean the top surface of the PD array base plate. I immediately picked up some black stuff. You can also see that the PEEK parts are covered with black stuff.

Fifth picture shows the PEEK parts. I wiped the top parts but the bottom one is yet to be cleaned. You can easily see the difference.

6th and 7th picture shows deep scuff on the class A surface of the array PD structure, which seemed to have most accumulated the black stuff.

Sheila, Matt Todd

We are having more incidences of the nonstationary noise 20-60 Hz that correlates with the CO2 ISS channel. 

Here's a collection of links related to this issue in the past: 

• Derek lasso run for time of sudden turn off: 81764,
• detchar git issue 306
• detchar git issue about running lasso for max: 246
• detchar git issue when sqz seemed to be involved in this noise: 237
• correlation with filter cavity control signal 78485
• Last May noise seemed to go away when the squeezer was blocked: 78033
• Other alogs from last May, this seemed urelated to PR3 moves but did happen at the same times: 77980

Here is a Lasso result for the noisy lock from this weekend: lasso Feb 9. Jane Glanzer is working on running lasso for some of the recent noisy times including the max as well as mean channels, so that may provide additional clues. We still see the ITMX CO2 ISS channel correlated with range.  Note, on Feb 7th Lasso chooses  H1:IOP-OAF_L0_MADC2_EPICS_CH15 which is the same thing as ITMX_CO2_ISS_CTRL2_INMON,

For the 9th the Rayleigh statistic also clearly shows this issue: summary page for Feb 9th, but comparing this to one of our normal days (range just below 160 and stable on Feb 4th) we also see nonstationarity at these frequencies.  So, it is possible that we normally have this non stationary noise at a lower level and it is always limiting our sensitivity.

Feb st we had an incident where the ISS CO2 channel was correlated with the range, screenshot.  Feb 1st there was also a remarkable change in the FC length control signal peak to peak, which has not shown any correlation with these range drops in the last week and a half, but did last may (78485).  Matt found this alog about squeezer issues on the 1st, 82581, we adjusted the SHG temperature, and fiber polarization, and there was a temperature excursion in the FCES. The FC length control signal was noisy from Jan 2nd to Feb 1st, and has been back to normal since. 

Operator request:  If operators see the range fluctuating with lots of noise between 20-40 Hz, (similar to Feb 9th), could you drop out of observing and go to no squeezing for 10 minutes or so?  We would like to see if this problem comes and goes with squeezing as it did last May. 

TITLE: 02/10 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 7mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.39 μm/s
QUICK SUMMARY:

• 21:35 UTC observing, we've been locked for just over 2 hours

TITLE: 02/10 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 155Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Commissioning this morning and a few lock losses. The PR2 spot was moved again so the lock reacquisition was slower since Sheila needed to pico for POP QPDs. Other than that relocking has been automated.
LOG:

• 1623 Observing
• 1634 Commissoining start
• 1807 Lock loss
  • Commissioners decided to do more PR2 spot moving, so lock recovery involved more intial alignments and picoing.
• 2118 Observing

H1 back to observing at 21:18 UTC following commissioning time. Were getting some DIAG_MAIN notifications after going to max power about the POP X PZT being railed; Sheila says we should fix this but can wait for now. The TMS_SERVO Guardian has a note about this being due to different PR3 alignment.

Accepted new POP_A offsets of 0 in ASC OBSERVE.snap table once at NLN (screenshot attached).

J. Freed

ETMX shows strong coupling of BOSEM noise between 10-20Hz by about a factor of 30 below DARM from most sensors.

Today I did damping loop injections on all 6 BOSEMs on the ETMX M0. This is a continuation of the work done previously for ITMX, ITMY, PR2, PR3, PRM, SR2, SR3, and SRM. As with PRM, gains of 300 and 600 were collected for SR3 (300 is labled as ln or L).  Calibration lines were off.

Sheila, Matt T, Mayank, Jennie W

tl;dr: After previous PR2 moves last week, we measured the spot clipping on scraper baffle (and exiting HAM3 viewport) to be 8mW in lock. After measuring this we unlocked for unknown reason and so team PR2 moved 6mm towards the centre of PR2 in yaw while unlocked. We estimate we are roughly centred on PR2 now.

Today Sheila and I measured the spot coming out of the HAM3 viewport as was done by Robert in this entry. The process is replace the black glass guillotine with lexan guillotine, take off the illuminator, clip a lens on a stalk to the top of the guillotine and align this with the beam coming out of the viewport. Not all the light is now captured by the lens as the spot is now more a semi-circle of a clipped beam. We moved the power metre behind the lens till we found the max power we could get on the power metre. This was 8mW and the PR3 yaw slider was at around -74 microradians.

After we came back to control room the IFO lost lock so it was decided to move towards the centre of PR2 which had been measured by Sheila using an A2L measurement at the start of the commissioning period.

Matt tuned down on PR3 yaw in 3 microradian steps to -232.4 microradians. Each step he tuned the 8X picomotor to bring back the DIFF and COMM ALS beatnotes. Every so often it is also neccessary to step up the pitch on PR3 to compensate for the cross-coupling of yaw to pitch. The ndscope image for the moves is here. Matt left the picomotor like this and the sliders like this.

FAMIS 31072

Since our work in the enclosure last week taking pump diode slope measurements (alogs 82636 and 82635), several trends have changes. A majority of the pump diode monitors are at different levels, power out of both amplifiers is higher (AMP2 seems slightly noisier), PMC transmitted power is higher, PMC reflected power is lower and has not been increasing since last week. This is the first time I can recall it not having a steady increase since immediately after the last NPRO swap late last year.

Mon Feb 10 10:18:24 2025 INFO: Fill completed in 18min 21secs

Gerardo confirmed a good fill curbside. TCmins [-38C, -37C] OAT (-3C, 26F) DeltaTempTime 10:18:24

1423246039

The lock loss occurred during commissioning time but no activity was going on at the time.

Attached are monthly TCS trends for CO2 and HWS lasers.  (FAMIS link)

Sheila and I are continuing to check various PD calibrations (82260). Today we checked the POP A LF calibration.

Currently there is a filter labeled "to_uW" that is a gain of 4.015. After some searching, Sheila tracked this to an alog by Kiwamu, 13905, with [cnts/W] = 0.76 [A/W] x 200 [Ohm] x 2¹⁶ / 40 [cnts/V]. Invert this number and multiply by 1e6 to get uW/ct.

Trusting our recalibration of IM4 trans, we have 56.6 W incident on PRM. We trust our PRG is about 50 at this time, so 2.83 kW are in the PRC. PR2 transmission is 229 ppm (see galaxy optics page). Then, the HAM1 splitter is 5.4% to POP (see logs like 63523, 63625). So we expect 34 mW on POP. At this time, there was about 30.5 mW measured on POP according to Kiwamu's calibration.

During commisioning this morning, we added the final part of the ESD glitch limiting, by adding the actual limit part to ISC_LOCK. I added a limit value of 524188 to ETMX_L3_ESD_UR/UL/LL/LR filter banks, which are the upstream part of the 28 bit dac configuration for SUS ETMX. These limits are engaged in LOWNOISE_ESD_ETMX, but turned off again in PREP_FOR_LOCKING.

In LOWNOISE_ESD_ETMX I added:

            log('turning on esd limits to reduce ETMX glitches')
            for limits in ['UL','UR','LL','LR']:
                ezca.get_LIGOFilter('SUS-ETMX_L3_ESD_%s'%limits).switch_on('LIMIT')

So if we start losing lock at this step, these lines could be commented out. The limit turn-off in PREP_FOR_LOCKING is probably benign.

Diffs have been accepted in sdf.

I think the only way to tell if this is working is to wait and see if we have fewer ETMX glitch locklosses, or if we start riding through glitches that has caused locklosses in the past.

Ryan Crouch, Rahul Kumar

The assembly, balancing and testing of all 12 HRTS (Ham Relay Triple Suspension) for O5 is now complete. Currently all 12 HRTS has dummy optic installed at the bottom stage and once the mirrors are ready (with prisms bonded) then it will be replaced (later this year). I am attaching several pictures from the lab which shows all 12 HRTS staged on the optical bench. Later, six of the suspensions will be transported to LLO.

This plot compares the of transfer function performance of all 12 HRTS for all 6 degrees of freedom. We are still analyzing this data and there is scope for improving a couple of them (especially highlighted in green trace). Sometimes, it is as simple as adjusting the flag position wrt to LED/PD in bosems, and other times further fine tuning the balance and alignment of the blade springs.

The final two HRTS which were assembled by us are of OM0 configuration. This has bottom mass (M3 stage) actuation using AOSEM standoff assembly (as per D2300180_v2) as shows in the picture over here. The magnets used at M3 stage is 2.0 mm D x 0.5 mm T, SmCo. The transfer function results for both the OM0 configurations are as follows - attachment01 and attachment02. Both of them look healthy, when compared with the model.

Given below are the OLC, offsets and gains of the bosems attached to OM0 sn02,

In alog 65804 Ross, Mitchell and I adjusted and dithered ITMX to see how much reflection off the ITM the ETM Hartmann sees. See attached for the ETMX HWS beam refected off the ITMX. This is a known issue in both ETM HWSs. It may explain why ETM ring heater tests look okay but not powerups.