aLIGO LHO Logbook

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Reports until 16:22, Thursday 13 March 2025

H1 General

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oli.patane@LIGO.ORG - posted 16:22, Thursday 13 March 2025 (83365)

Ops Eve Shift Start

TITLE: 03/13 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 25mph Gusts, 16mph 3min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.34 μm/s
QUICK SUMMARY:

At ENGAGE_ASC_FOR_FULL_IFO and working on relocking with lots of lower state locklosses. These seem to be due to various causes, including high-ish winds& gusts. Secondary microseism is also a bit elevated.

LHO FMCS

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eric.otterman@LIGO.ORG - posted 14:55, Thursday 13 March 2025 (83361)

H2 HVAC sub panel breaker replacement

I replaced the three pole, 25 amp circuit breaker which controls the line voltage for an HVAC circuit in the H2. Voltage output was 490 volts.The previous breaker was damaged by heat caused by a loose connection.

H1 General

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thomas.shaffer@LIGO.ORG - posted 14:54, Thursday 13 March 2025 (83360)

Lock loss 2132UTC

No obvious cause but there was a small change in the PRG a second or two before lock loss.

H1 ISC (OpsInfo)

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sheila.dwyer@LIGO.ORG - posted 11:57, Thursday 13 March 2025 - last comment - 11:22, Tuesday 18 March 2025(83357)

ALS DIFF sped up a bit

We lost lock from the calibration, so we tried to lock ALS without the linearization (some background in this alog: 83278.) An active measurement of the transfer function from DRIVEALIGN_L to MASTER out was 1 without the linearization, and -0.757 with the linearization on. So I've changed the DRIVEALIGN gain to -1.3 in the ALS_DIFF guardian when the use_ESD_linearization is set to false.

We tried this once, and it stayed locked for a DARM gain of 400, but unlocked as the UIM boosts were turning on. We tried this again but it also didn't lock DIFF, so it is now out of the guardian again.

I looked at a few more of the past ALS DIFF locks, both sucsesful and unsucsesful attempts we are saturating the ESD (either the DAC or the limiter in the linearization) in the first steps of locking DIFF. We do these steps quite slowly, stepping the darm gain to 40 waiting for the DARM1 ramp time, stepping it to 400, then waiting twice the ramp time, then engaging the boosts for offloading to L1. I reduced the ramp time from 5 seconds to 2 seconds to make this go faster. This worked on the first locking attempt, but that could be a coincidence.

We will leave this in for a while, so that we can compare how frequently we loose lock at LOCKING_ALS. In the last 7 days we've had 48 LOCKING_ALS locklosses, and 19 locklosses from NLN, so roughly 2.5 ALS locklosses per lock stretch.

Comments related to this report

sheila.dwyer@LIGO.ORG - 10:14, Tuesday 18 March 2025 (83427)

Since the time of this alog, around 19 UTC on March 13th, we've had 68 locking_ALS locklosses and 12 NLN locklosses, so about 6 locklosses per sucsesful lock. It seem though that the change to 2 seconds was never in place, and the guardian code still said 5 seconds. So this issue seems to be getting worse without any change.

Now I've loaded the change to 2 seconds, so this should be sped up after today's maintence window.

sheila.dwyer@LIGO.ORG - 11:22, Tuesday 18 March 2025 (83429)

I've looked at a bunch more of these locklosses, and they mostly happen in the time when the DARM gain is ramping, less often as the boosts are coming on in L1, and 1 I saw happened while COMM was locking.

In all the cases the linearization seems to hit its limiter before anything else goes wrong.

H1 CAL

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thomas.shaffer@LIGO.ORG - posted 11:11, Thursday 13 March 2025 (83347)

Failed Calibration Sweep 1530 UTC

The calibration measurement caused another lock loss at the end of the measurement (alog83351)

Simulines start:

PDT: 2025-03-13 08:36:53.447733 PDT
UTC: 2025-03-13 15:36:53.447733 UTC
GPS: 1425915431.447733

End of script output:

2025-03-13 15:58:59,923 | INFO | Drive, on L2_SUSETMX_iEXC2DARMTF, at frequency: 42.45, and amplitude 0.41412, is fin
ished. GPS start and end time stamps: 1425916738, 1425916753
2025-03-13 15:58:59,923 | INFO | Scanning frequency 43.6 in Scan : L2_SUSETMX_iEXC2DARMTF on PID: 795290
2025-03-13 15:58:59,923 | INFO | Drive, on L2_SUSETMX_iEXC2DARMTF, at frequency: 43.6, is now running for 23 seconds.
2025-03-13 15:59:01,039 | INFO | Drive, on DARM_OLGTF, at frequency: 1083.3, and amplitude 1e-09, is finished. GPS st
art and end time stamps: 1425916738, 1425916753
2025-03-13 15:59:01,039 | INFO | Scanning frequency 1200.0 in Scan : DARM_OLGTF on PID: 795280
2025-03-13 15:59:01,039 | INFO | Drive, on DARM_OLGTF, at frequency: 1200.0, is now running for 23 seconds.
2025-03-13 15:59:02,168 | INFO | Drive, on L1_SUSETMX_iEXC2DARMTF, at frequency: 11.13, and amplitude 13.856, is fini
shed. GPS start and end time stamps: 1425916735, 1425916753
2025-03-13 15:59:02,168 | INFO | Scanning frequency 12.33 in Scan : L1_SUSETMX_iEXC2DARMTF on PID: 795287
2025-03-13 15:59:02,169 | INFO | Drive, on L1_SUSETMX_iEXC2DARMTF, at frequency: 12.33, is now running for 25 seconds
.
2025-03-13 15:59:07,162 | ERROR | IFO not in Low Noise state, Sending Interrupts to excitations and main thread.
2025-03-13 15:59:07,163 | ERROR | Ramping Down Excitation on channel H1:SUS-ETMX_L2_CAL_EXC
2025-03-13 15:59:07,163 | ERROR | Ramping Down Excitation on channel H1:SUS-ETMX_L3_CAL_EXC
2025-03-13 15:59:07,163 | ERROR | Ramping Down Excitation on channel H1:CAL-PCALY_SWEPT_SINE_EXC
2025-03-13 15:59:07,163 | ERROR | Ramping Down Excitation on channel H1:SUS-ETMX_L1_CAL_EXC
2025-03-13 15:59:07,163 | ERROR | Aborting main thread and Data recording, if any. Cleaning up temporary file structu
re.
2025-03-13 15:59:07,163 | ERROR | Ramping Down Excitation on channel H1:LSC-DARM1_EXC
ICE default IO error handler doing an exit(), pid = 795246, errno = 32
PDT: 2025-03-13 08:59:11.496308 PDT
UTC: 2025-03-13 15:59:11.496308 UTC
GPS: 1425916769.496308

Images attached to this report

H1 SEI

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ryan.crouch@LIGO.ORG - posted 10:22, Thursday 13 March 2025 (83269)

H1 ISI CPS Noise Spectra Check - Weekly

Closes FAMIS 26034, last checked in alog83240

The script reports high freq noise is elevated for these BSCs.

ITMX_ST1_CPSINF_V1
- It doesn't look higher than it did last week.
ETMY_ST2_CPSINF_V2
- ST1_H1, ST2_{V1,V3} also look elevated at high frequency.

All the HAMs noise looks to have reduced except for HAM8, particularly a peak at just over 1 Hz in H3 and H1 looks reduced on almost all of the HAMs. HAM8s mid freq looks overall noisier and the high freq V3 peak looks elevated (just over 100Hz).

Non-image files attached to this report

CPS_spectra_09:45-03_13_2025.pdf

H1 General (CAL)

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thomas.shaffer@LIGO.ORG - posted 09:03, Thursday 13 March 2025 - last comment - 10:54, Thursday 13 March 2025(83351)

Lock loss 1530UTC

This happened at the end of the calibration measurement. This also happened last week (alog83210).

Comments related to this report

ryan.crouch@LIGO.ORG - 09:49, Thursday 13 March 2025 (83352)CAL

The last 3 calibration measurements have ended in locklosses, todays, saturdays and last thursdays (these link to the lockloss tool webpages). The 3 locklosses look fairly similiar but looking at the ETMX signals, todays seemed a little stronger of a lockloss? Compared to Saturday and last thursday.

Last thursdays lockloss alog83239

Images attached to this comment

camilla.compton@LIGO.ORG - 10:54, Thursday 13 March 2025 (83354)CAL, SUS

Looking at the same channels that Vlad did in 82878 and Ryan's above ETMX channels, the 42Hz growing wobble in DARM/ETMX seems to start as soon as the DAM1_EXC is ramped on to it's full amplitude, plot attached. The 42Hz is seen as an excitation into H1:SUS-ETMX_L2_CAL_EXC_OUT_DQ, plot attached. Maybe the ETM is not fully stable at that frequency?

Looking at a successful calibration sweep Feb 22nd 82973, There was no instability when the 42Hz oscillation was turned onto ETMX L2, plot attached.

Images attached to this comment

LHO General

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tyler.guidry@LIGO.ORG - posted 08:33, Thursday 13 March 2025 (83348)

LSB Roof Replacement

Overhaul of the failed roofing at the LSB finished on Tuesday.


T. Guidry

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H1 CDS

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david.barker@LIGO.ORG - posted 08:22, Thursday 13 March 2025 - last comment - 16:24, Thursday 13 March 2025(83345)

LVEA vacuum glitch coincident with H1 lockloss

We had a vacuum glitch in the LVEA at 01:57 Thu 13mar2025 PDT which was coincident with a lockloss. The glitch was below VACSTAT's alarm levels by an order of magnitude, so no VACSTAT alert was issued.

The glitch is seen in most LVEA gauges, and took about 10 minutes to pump down.

Attached plots show a sample of LVEA gauges, the VACSTAT channels for LY, and the ISC_LOCK lockloss.

Images attached to this report

Comments related to this report

thomas.shaffer@LIGO.ORG - 08:29, Thursday 13 March 2025 (83346)

Adding the lock loss tag and a link to the lock loss tool - 1425891454

There's no blatantly obvious cause. The wind was definitely picking up right before the lock loss, which can be seen in many of the ASC loops, but I'm not sure it was enough to cause the lock loss.

camilla.compton@LIGO.ORG - 09:58, Thursday 13 March 2025 (83353)

This may be a what-came-first the LL or the VAC spike scenario but looking at the past 3 hour trend of H1:CDS-VAC_STAT_LY_Y4_PT124B_VALUE attached, it does not go above 3.48e-9. However 3 seconds before the lockloss, it jumps to 3.52e-9 attached. This seems suspiciously like whatever caused the VAC spike came before the lockloss.

There is a LL issue open to add a tag for this: #227, as it was previously seen in 82907.

Images attached to this comment

janos.csizmazia@LIGO.ORG - 13:35, Thursday 13 March 2025 (83359)

The only possible plausible vacuum glitch without the laser hitting something first, is IP-glitch. Gerardo is looking into this now.

Otherwise, I would say the laser hit something, which didn't cause lockloss right away (only 3 seconds later), but - obviously - caused pressure spike.

The rising wind is just too big of a coincidence to me..

jordan.vanosky@LIGO.ORG - 15:14, Thursday 13 March 2025 (83362)

Corner RGA caught small change in H2 and N2 at the time of the vacuum glitch. AMU 2 delta = 5.4e-10 amp, AMU 28 delta = 1.61e-10 amp

Attached is a screenshot of RGA scan just before the vac glitch (1:57:02 AM 3/13/25), and second screenshot is ~10 seconds after. Top trace is the 0-100AMU scan at that time, bottom trace is the trend of typical gas components (AMU 2, 18, 28, 32, 40, 44), over ~50 minutes. Vertical line on bottom trace corresponds to time RGA was collected

RGA is a Pfeiffer Prisma Plus, 0-100AMU, with 10ms dwell time, EM enabled with 1200V multiplier voltage. Scans run continuous 0-100AMU sweeps

Images attached to this comment

gerardo.moreno@LIGO.ORG - 16:24, Thursday 13 March 2025 (83364)VE

Main ion pumps reacted to the "pressure spike" after it was noted by other instruments such as the vacuum gauges, see attached plot, first one.

The second plot shows the different gauges located at the corner station, the "pressure spike" appears to be noted first by two gauges PT120 (gauge on dome of BSC2) and PT152 (gauge located at the relay tube). The amplitude of the "pressure spike" was very small, signature only was noted at the corner station, not noted at Mids or Ends.

Two of the ion pumps at the filter cavity tube responded to the "pressure spkie", see third attachment.

Also, the gauges located on the filter cavity tube noted the spike, including the "Relay Tube".

Images attached to this comment

LHO General

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thomas.shaffer@LIGO.ORG - posted 07:34, Thursday 13 March 2025 - last comment - 08:51, Thursday 13 March 2025(83344)

Ops Day Shift Start

TITLE: 03/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 134Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 24mph Gusts, 18mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.28 μm/s
QUICK SUMMARY: Locked for 1.5 hours. Planned calibration and commissioning today. Elevated winds already present, some gusts above 40mph. The PSL 101 dust monitor has been in alarm.

Comments related to this report

thomas.shaffer@LIGO.ORG - 08:38, Thursday 13 March 2025 (83349)

Our range has been diving down to 130 or so then recovering. It doesn't seem to be the PIs or the end station noise that we were looking at recently. Rumors in the control room are that it was the squeezer, stay tuned for another alog.

Images attached to this comment

camilla.compton@LIGO.ORG - 08:51, Thursday 13 March 2025 (83350)DetChar, SQZ

Sheila, TJ, Camilla. In 83330 we showed that the SQZ servo with edited ADF PLL phase 83270 was working well, but it's been running away this morning, plot attached. We're not sure yet what changed to make it become unstable but this is similar to why we turned it off in Feb.

Tagging DetChar as the times when the SQZ phase and IFO range jump a lot (2025/03/13 14:49 UTC and 15:10UTC) may have glitches.

Images attached to this comment

H1 ISC (ISC)

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keita.kawabe@LIGO.ORG - posted 23:25, Wednesday 12 March 2025 - last comment - 10:46, Thursday 13 March 2025(83343)

Old ZM2 optic transmission VS AOI (Rahul, Keita)

As a potential optic for the new TT for the in-vac POPX WFS in HAM1, we tested the transmission of what is supposed to be the old ZM2 mirror from O3 days as a function of AOI.

The results summarized below doesn't make sense because it's least transmissive at 0 deg AOI and it's not HR at 45 deg (3.3% transmission). It's supposed to be E1700103 according to the label but with a handwritten note saying "verify??? doesnt look the same" or something like that. Anyway, if it is indeed E1700103, it should be R>99.99% @ 1064nm for both P and S at 45 +- 5 deg AOI.

This mirror is probably usable for POPX in that the transmission is not disastrously big at the proposed AOI (~30deg or so?) but this is a mystery optic as far as I'm concerned. If the mirror in ZM1 is better, we'll use it.

AOI (deg)	power in transmission (mW)	power transmission in %
0	0.05	0.03
10	0.08	0.04
15	0.09	0.05
20	0.11	0.061
25	0.16	0.089
30	0.28	0.16
35	0.44	0.24
40	1.23	0.68
45	5.94	3.3

Other things to note:

We mounted the mirror in a class A siskiyou mirror holder on a dirty rotational stage with a clean sheet of foil inbetween so we can easily change the AOI in YAW.

The apparatus was NPRO - BS (to throw away some power) - HWP - PBS cube transmission (to select P-pol) - steering - ZM2 optic transmission - power meter.

The beam height between the steering mirror and the ZM2 optic was leveled, then ZM2 was adjusted so the beam retroreflects within +-2mm over 19 inches, and this became our AOI=0 reference point with uncertainty of ~+-2mm/19inches/2 rad ~ +-0.1deg. We used the indicator on the rotational stage to determine the AOI, and overall AOI error should have been smaller than 1 deg.

Before/after the measurement, the power impinging the HR side of the mirror was 180.3mW/176.1mW. Since the transmitted power only had 2-digits precision at best, I used 1.8e2 mW as the input power. The ambient light level was less than 10uW and is ignored here.

Another obvious candidate is ZM1 (again from O3 days). The mirror was not removed from TT after deinstallation though. We'll see if we can roughly determine the AOI while the mirror is still suspended, as it's a hassle to remove it from the suspension and there's a risk of chipping.

Comments related to this report

rahul.kumar@LIGO.ORG - 10:46, Thursday 13 March 2025 (83356)ISC, SUS

I found out that ~~old ZM2 (HTTS, HAM5) optic is E1000425~~ and not E1700103 (which is for the old HTTS ZM1 – HAM6). For reference please see Stuart’s LLO alog – 64077.

H1 SUS (ISC)

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thomas.shaffer@LIGO.ORG - posted 10:49, Wednesday 12 March 2025 - last comment - 12:50, Thursday 13 March 2025(83332)

pi31 slow ringup causing range drop

We noticed that the range was dropping even lower than our already low ~145Mpc. There was a lot of low frequency noise that was creeping up. Sheila suggested that we look at the PIs and sure enough, PI31 had started to slowly creep up the same time as the range degredation (see attached). The SUS_PI guardian node will turn on the damping at 3 according to the H1:SUS-PI_PROC_COMPUTE_MODE31_RMSMON channel and turn it back off when it gets below 3. For now we just tried changing that threshold to 0 to all for continuous damping. This let the mode damp down completely and it brought our range back up.

We should think more about damping this down lower and having two thresholds, an on an off.

Images attached to this report

Comments related to this report

thomas.shaffer@LIGO.ORG - 11:06, Wednesday 12 March 2025 (83334)

Changed the threshold to 1. At 0 the node would continuously search for a new phase thinking that it needed to damp it further.

sheila.dwyer@LIGO.ORG - 13:16, Wednesday 12 March 2025 (83335)

The first attached screenshot shows the spectrum around 10.4 kHz (edited to fix typo), the mode which rang up and caused this issue is at 10428.38 Hz, previously identified as being in the y arm (Oli's slides).

The behavoir seemed pretty similar to what we saw a few weeks ago, 82961, with broad nonstationary noise in DARM.

The downconversion doesn't seem to be caused by the damping, it started to have a noticable impact on the range while the damping was off, and when the damping came on and reduced the amplitude of the mode the range improved.

In the ndscope screenshot attached you can see the range that we are using on the DCPDs ADC, this is a 20 bit DAC so it would saturate at 524k counts, when this PI was at it's highest today it was using 10% of the range, the DARM offset takes up about 20% of the ADC range.

The third attachment is the DARM spectrum at the time of this issue, as requested by Peter. As described in 83330 our range is decreasing with thermalization in each lock, the spectrum shows the typical degredation in the spectrum in these last few days since the SQS angle servo has been keeping the squeezing more stable. The excess noise seen when the PI was rung up has a similar spectrum to the excess noise we get after thermalization.

Also, for some information about these 10.4kHz PI modes, see G1901351

Images attached to this comment

sheila.dwyer@LIGO.ORG - 12:50, Thursday 13 March 2025 (83358)

Jeff pointed me to 82686 with the suggestion to check the channels that have different digital AA.

The attached plot shows DCPD sum, and two alternatives, in red is H1:OMC-DCPD_16K_SUM1_OUT_DQ which has a high pass to reduce the single precision noise and no digital AA filters (and some extra lines), SUM2 has 1 digital AA filter and the high pass, and DCPD sum is the darm channel and has 2 digital AA filters and no high pass. The broadband noise is the same for all of these, so digital aliasing doesn't seem to be involved in adding this broadband noise.

Images attached to this comment

H1 SUS (TCS)

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thomas.shaffer@LIGO.ORG - posted 15:58, Friday 20 August 2021 - last comment - 10:44, Thursday 13 March 2025(59684)

O3 ZM2 removed from HAM5

WP9880

I removed the O3 ZM2 tip tilt from HAM5 and moved the SRM heater optics to be used in the upcoming temporary laser setup for OFI alignment.

Summary of activities:

Dust counts were 0's or low 10's before and after opening soft covers, using grey handheld
Collected 4" and 1" CC samples with Nidhi's help
Removed cables, BOSEMs, and optic from ZM2
Corey and I bagged the TT, BOSEMs, TT spacer, beam dump spacer, dog clamps
I left 3 beam dumps and the SRM heater mirrors on the South side of the table to be, potentially, used for the upcoming temp. laser setup.

Comments related to this report

rahul.kumar@LIGO.ORG - 10:44, Thursday 13 March 2025 (83355)SUS

just for info - the optic used for ZM2 (HTTS, HAM5) optic is E1000425 - currently stored at LHO.

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