TITLE: 06/19 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 6mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.10 μm/s
QUICK SUMMARY:

IFO is in NLN and OBSERVING since 05:53 UTC (~9hr lock!)

Plan is to continue observing.

TITLE: 06/19 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Tony
SHIFT SUMMARY:

Currently relocking and at MOVE_SPOTS. We lost lock earlier after having been locked for 4.5 hours, with half of that locked time being spent messing with the SQZ filter cavity and trying to keep it from unlocking(85169). We still haven't figured out why it was unlocking. For the night we are keeping the FC beam spot control off. SDFs have been accepted to keep the FC beam spot control filter inputs off(sdf). We don't really think that was the issue, but we got out longest span (15 mins before LL) of a locked sqzer after turning it back off after the unlocking issue had started. We'll look more into the sqzing issues tomorrow, so for Tony: if we have SQZ issues overnight, just go to Observing without SQZing and it'll get dealt with tomorrow.

LOG:

23:30 Relocking and in MOVE_SPOTS
    23:40 Earthquake mode activated
23:48 NOMINAL_LOW_NOISE
    23:50 Observing
    00:10 Back to CALM
    01:40 Out of Observing due to SQZ unlocking
    01:43 Back into Observing
    01:47 Out of Observing due to SQZ unlocking
    01:50 Back into Observing
    01:56 Out of Observing due to SQZ unlocking
    02:31 Back into Observing
    02:32 Out of Observing due to SQZ unlocking
    03:16 Back into Observing
    03:17 Out of Observing due to SQZ unlocking
    03:29 Back into Observing
    03:29 Out of Observing due to SQZ unlocking
    03:45 Back into Observing
    03:51 Out of Observing due to SQZ unlocking
    03:57 Back into Observing
    03:59 Out of Observing due to SQZ unlocking
    04:03 Back into Observing
04:21 Lockloss
    - Manual initial alignment

Summary:

Robert's alog 84015 shows that IFO beam hitting the [+X, +Y] side barrel/edge of the BS could be coupling to DARM somehow.

Out of curiosity, we scanned the BS spot position in YAW with 2mm steps from -6mm to +6mm (measured along the BS surface, -6mm being the closest to the [+X,+Y] side barrel) while dithering the YAW angle of PR2 at 31Hz, and measured the coupling from the dither to DARM in nominal low noise.

Expectation is/was that the coupling monotonically gets worse as the beam approaches the [+X, +Y] side, but we didn't see such a simple pattern. See the 1st attachment showing H1:LSC-DARM_IN1_DQ/PR2_M3_DITHER_Y_OUT TF at the dither frequency. There could be a minima at around +2mm position but there's no phase flip around that point. No clear conclusion here.

BS spot position and its (rough) calibration

The camera servo uses the centroid position of BS spot obtained from GigE camera image in raw pixels. Nominal spot position on BS is (230, 236) for (P, Y), which is given by H1:ASC-CAM_PIT1_OFFSET=-230, H1:ASC-CAM_YAW1_OFFSET=-236.

The camera is looking at BS from -X+Y direction (WBSC2 G8 viewport). Positive increase in YAW position, which appears as a shift towards the right for the camera, means the shift in -X-Y direction on the BS surface (i.e. away from +X+Y side of the BS).

The entire frame width (640 pixels) of the GigE image is very roughly the same with the diameter of the BS (370mm nominal), so the calibration of the camera image is 370mm/640pix.  Using this, +2mm step is 2mm/(370mm/640pix) ~ 3.5 pixels.

BS spot steps were given by increasing/decreasing H1:ASC-CAM_YAW1_OFFSET by integer multiple of 3.5 pixels.

Note that BS is tilted by 45 degrees relative to X and Y axis, thus +2mm on the plot means [-sqrt(2),-sqrt(2)]mm in [X,Y] direction, respectively. 

We started with 0mm offset, then proceeded with -2mm, -4mm, -6mm, +2mm, +4mm and +6mm in this order. After each step, we waited until the camera servo settle, measured the transfer function at the injection frequency, and proceeded to the next step.

After we were done, spot position was set back to 0mm offset.

Injection

We made an injection of 8 counts pp at 30Hz into H1:SUS-PR2_M3_DITHER_Y_EXC, which made a huge peak in DARM. Injection was active from ~19:03 UTC to 20:14 UTC on 2025/06/18.

A2L

Before we started injection and before we moved the BS spot position, Ibrahim ran A2L script to set the A2L gains for quads. All measurements, even after BS spot was moved, was done with these A2L gains (4th attachment), and Ibrahim put these gains in the guardian.

A2L measurement was done with +6mm offset after all of the measurents were done, too, as we might need that data later (5th attachment).

DTT template

It's in /ligo/home/keita.kawabe/BSPOS\ VS\ jitter\ 20250618.

REF0-1: no exc, ref2-5: 0mm offset, ref6-9: -2mm, ref10-13: -4mm, ref14-17: -6mm, ref18-21: +2mm, ref22-25 +4mm, ref26-29: +6mm.

Lockloss at 06/19 04:21 UTC due to unknown causes

We are currently Locked and have been for over 3 hours. We've been dropping out of Observing a few timnes due to the FC unlocking, and a couple times it was able to relock itself, one time I had to adjust FC2, and currently I've been working on relocking it but I've been having trouble. I've adjusted FC2 to maximize flashes, I've trended back FC1 and FC2 to a time yesterday when the green trans was good based on the DAMP INMONs and now the M3 Witness channels, and none of that has worked. FC2 seems twice as noisy as usual in pitch and I'm wondering if that's affecting things? The wind is getting in the high 30s at M/EY?

Oli, Elenna

Oli and I combed through some of the recent locklosses by hand, and noticed that there are at least two that have a 13 Hz oscillation in the LSC channels just before the lockloss.

1434317297

1434276630

This is reminiscent to us of PRCL losing gain due to thermalization which has caused 11 Hz ring ups before. We should keep an eye out. Note that one of the above locklosses has the "earthquake" tag, but it's very clear that the ring up caused the lockloss.

Oli and I went back about 1 week and checked the NLN locklosses by eye and only found these two so far.

To start, we can periodically check PRCL OLG or other LSC OLGs during thermalization to make sure we aren't losing significant optical gain. Or we can inject a line during commissioning.

TITLE: 06/18 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Oli
SHIFT SUMMARY:

IFO is LOCKING in OMC_WHITENING

Productive shift in which we had commissioning until 2PM. We were locked for the majority of commissioning, only losing lock in the morning (lockloss alog 85151). We reached NLN after doing an initial alignment (manual as is the case until PRX can be automated) at 16:49 UTC.

Relevant alogs from commissioning:

• A2L Script Alog 85155
• SQZ ASC Comissioning: Alog 85149
• Guardian Reboot (fixing AWG issue): Alog 85152
• DC6 P Noise Budget Injection: Alog 85156
• Elenna SDF Diff Reversions: Alog 85158
• HAM1 ISI FF: Alog 85162

After commissioning, there was another lockloss (a few minutes into observing) where a mysterious length kick on the Y arm seems to have been the cause - Lockloss alog 85160.

Relocking was somewhat difficult (and is still in progress) primarily due to ALSX losing lock. Firstly, scan-align failed to lock ALSY despite counts over 1. A manual movement of 3 taps in EY P immediately fixed the problem. Secondly, scan-align engaged immediately after ALSX lost lock despite counts being ~1 (very good for ALSX). After this, ALSX stalled in “crystal frequency” locking for 20 minutes. If this keeps happening, we can change the threshold for the crystal frequency sweep since it seems to be only 1% away from threshold. After we got past this, DC0 had an error and Erik and Dave fixed it within 10 mins with no disruptions. Alog 85164

Otherwise, locking has been automatic and reliable. This just in: EQ incoming - velocity over 1 um/s means we’ll probably lose lock.

LOG:

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.

At 16:14:31 PDT h1daqdc0 crashed. Its EPICS IOC stopped running resulting in white boxes on MEDM. Last log was 15:56.

I connected a monitor to its VGA port, its console was showing the login prompt. The cursor was not flashing and an attached keyboard was unresponsive.

Erik and I rebooted the machine by pressing the front panel RESET button. It booted and started with no problems.

Currently we don't know why dc0 froze this way.

TITLE: 06/18 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: SEISMON_ALERT
    Wind: 27mph Gusts, 14mph 3min avg
    Primary useism: 0.11 μm/s
    Secondary useism: 0.09 μm/s
QUICK SUMMARY:

Currently relocking and in MOVE_SPOTS. Wind and ground motion are still a bit high.

Unknown cause lockloss. Could be attributed to the wind, since it is on the rise and expected to continue tonight. Gusts were over 30mph at the time of the lockloss.

It seems that there was a length kick in EY that was first seen causing the lockloss. Lockloss report.

There were a few SDF diffs before observing in ramp times that I think came from running various scripts like the A2L and the DARM offset step. I reverted all of the changes so we (hopefully) don't get another SDF diff next time we lock.

Sheila, Camilla

We can see large SQZ changes dependent on the OPO PZT value, we;vee seen this before, some alignment changes from this PZT should be adjusted for by FC AS and FC beamspot control. The FC beamspot control has been off since the vent, but we're turned FC beamspot control on again in the hope to reduce this dependency.

Yesterday we needed to turn the ASC on to improve high freq sqz 85147 and since we've started using the THERMALIZATION guardian 85083 to slowly adjust SRCL Offset, our squeezing and ASC error signals are reduced slightly (see below). We have turned back on the SQZ ASC as expect this new guardian will stop the ASC running away.

Now we have the THERMALIZATION guardian working, the ADF measured sqz ang change has reduced (see below), we want to try turning back on SQZ_ANG_SERVO which will take a little tuning of settings. You can see in this plot that when the OPo PZT changed, the servo would have adjusted the sqz angle too.

• THERMILIZATION GRD on, SQZ ASC off plot: ASC error 0.35, ADF sqz ang change 7.
• THERMILIZATION GRD off, SQZ ASC off plot: ASC error 0.4, ADF sqz ang change 18.
• THERMILIZATION GRD off, SQZ ASC on plot: ASC error N/A, ADF sqz ang change 11.

Also touched the SHG launch waveplates to decrease the rejected power in H1:SQZ-SHG_FIBR_REJECTED_DC_POWER.

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.