After finding that the source of the broad 60 Hz shoulders in L1 appears to be a problem with line subtraction, as reported in LLO alog 773549, we have checked for possible related issues in H1. We have found that unlike in L1, the broad shoulders appear after October 1st instead of after September 17th as can be seen by checking at L1:GDS-CALIB_STRAIN vs L1:GDS-CALIB_STRAIN_NOLINES vs L1:GDS-CALIB_STRAIN_CLEAN at different points in time during these dates, where the shoulders appear in NOLINES and CLEAN. It would also appear like before September 17th the substraction was not ideal either, since there are still some small shoulders
September 17:September 26:
October 1st:
October 2nd:
October 11th:
![]()
the current gstlal-calibration was installed at both sites on September 3rd (not September 5th as I've been telling people). At LHO at 17:52 UTC and at LLO at 17:19 UTC.
As in LLO, the shoulders seem to get worse getting closer to September 17th, but before then h(t) values for GDS_CALIB_STRAIN_NOLINES and GDS_CALIB_STRAIN_CLEAN shouldering 60 Hz still appear to be higher than GDS_CALIB_STRAIN, including before and after maintenance on September 3rd. Adding additional plots before and after September 3rd showing this behaviour. Example from June 10th:![]()
TITLE: 10/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 157Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: The FSS transmitted power has been dropping the past few (~4?) days, TPD notification has been flashing on OPS_OVERVIEW. 2 locklosses today, automated relocks. We've been locked for 2.5 hours.
LOG:
Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
---|---|---|---|---|---|---|
18:13 | FAC | Tyler | Mids | N | 3IFO checks | 18:46 |
TITLE: 10/11 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 157Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 7mph Gusts, 4mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.20 μm/s
QUICK SUMMARY: H1 has been locked and observing for 2 hours. Sounds like it's been a relatively quiet day so far.
We get another false positive VACSTAT alarm for PT132 due to a noise spike. Alarm was raised at 14:29, I cleared it by restarted vacstat_ioc on cdsioc0 at 15:41
The AIP for GV10 is red, system railed about 2 hours ago. System will be assessed next Tuesday or at the next opportunity, we may need to replace the ion pump for GV10.
FAMIS 26333, last checked in alog80540
All fans within noise range and largely unchanged compared to last check.
No clear reason why, the lockloss website isn't updating "online last update: 237.1 min ago (2024-10-11 09:23:15.156027)"
1412712883 Not tagged as an IMC lockloss.
Fri Oct 11 10:12:04 2024 INFO: Fill completed in 12min 0secs
Gerardo confirmed a good fill curbside. TCs looking much better today.
Lockloss at 16:21 UTC (9:47 lock)
18:13 UTC Observing
TITLE: 10/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 154Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 4mph Gusts, 2mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.17 μm/s
QUICK SUMMARY:
I adjusted the OPO temperature from 14:37-14:39, the high freq looks a little better now, but its still not optimal.
TITLE: 10/11 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: TJ
SHIFT SUMMARY:
IFO is LOCKING at FIND_IR. I see IR resonances in both Comm and Diff (screenshot) so I believe guardian will be able to find IR (though it has now taken a few mins).
Super calm shift. Was observing the entire time until at 04:28 UTC, we had a Lockloss (Lockloss alog 80610).
LOG:
Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
---|---|---|---|---|---|---|
04:10 | VAC | Janos | EY | N | Aurora | 04:50 |
Lockloss after 9hrs and 45 minutes in NLN.
Cause so far unknown but known not to be the PSL (IMC and ASC lost lock 200ms apart).
Closes FAMIS 26011. Last checked in alog 80261.
No significant changes from last week.
TCS Monthly Trends
Closes FAMIS 28453. Last checked in alog 79893.
Blade tips on BBSS M1 were lowered to -3.0mm (previously -1.5mm) and transfer functions measurements were taken on October 04th. See Ibrahim's alog for an overview of our issues with the BBSS and why the blade heights have been changed.
Results for this set of transfer functions
Length and pitch for this set of transfer functions compared to previous (aug 30) LHO measurements and LLO October 7th measurements, zoomed
I ran the noise budget injections for frequency noise, input jitter (both pitch and yaw) and PRCL. All injections were run with CARM on one sensor (REFL B). The cable for the frequency injection is still plugged in as of this alog, but I reset the gains and switches so we are back on two CARM sensors and the injection switch is set to OFF.
All injections are saved in the usual /ligo/gitcommon/NoiseBudget/aligoNB/aligoNB/H1/couplings folder under Frequency_excitation.xml, IMC_PZT_[P/Y]_inj.xml, and PRCL_excitation.xml.
I realized an intensity noise injection might be interesting, but when I went to run the template for the ISS excitation, I was unable to see an excitation. I think there's a cable that must be plugged in to do this? I am not sure.
*********Edit************
Ryan S. sent me a message with this alog that has notes about how intensity noise injections should be taken. Through this conversation, I realized that I had misread the instructions in the template. I toggled an excitation switch on the ISS second loop screen, when I should have instead set the excitation gain to 1.
I was allowed another chance to run the intensity injections, and I was able to do so, using the low, middle, and high frequency injection templates in the couplings folder.
Also, the Input jitter injections have in the past been limited to 900 Hz, because the IMC WFS channels are DQed at 2048 Hz. However, the live IMC channels are at 16 kHz, so I edited the IMC injection templates to run up to 7 kHz, and use the live channels instead of the DQ channels. That allowed the measurements to run above 900 Hz. However, the current injections are band-limited to only 1 or 2 kHz. I think we can widen the injection band to measure jitter up to 7 kHz. I was unable to make those changes because we had to go back to observing, so this is future to-do item. I also updated the noise budget code to read in the live traces instead of the DQ traces.
Unfortunately, in my rush to run these injections, I forgot to transition over to one CARM sensor, so both the intensity and jitter measurements that are saved are with CARM on REFL A and B.
I ran an updated noise budget using these new measurements, plus whatever previous measurements were taken by Camilla in this alog. Reminder: the whole noise budget is now being run using median averaging.
I used a sqz time from last night where the range was around 165 Mpc, starting at GPS 1412603869. Camilla and Sheila took a no-sqz data set today starting at 1412607778. Both data sets are 600 seconds long. I created a new entry in gps_reference_times.yml called "LHO_O4b_Oct" with these times.
To run the budget:
>conda activate aligoNB
>python /ligo/gitcommon/NoiseBudget/aligoNB/production_code/H1/lho_darm_noisebudget.py
all plots found in /ligo/gitcommon/NoiseBudget/aligoNB/out/H1/lho_darm_noisebudget/
I made one significant edit to the code, which is that I decided to separate the laser and input jitter traces on the main DARM noise budget. That means that the laser trace is now only a sum of frequency noise and intensity noise. Input beam jitter is now a trace that combines the pitch and yaw measurements from the IMC WFS. Now, due to my changes in the jitter injections detailed above, these jitter injections extend above 900 Hz. To reiterate: the injections are still only band-limited around 2 kHz, which means that there could be unmeasured jitter noise above 2 kHz that was not captured by this measurement.
One reason I wanted to separate these traces is partly because it appears there has been a significant change in the frequency noise. Compared to the last frequency noise measurement, the frequency noise above 1 kHz has dropped by a factor of 10. The last time a frequency noise injection was taken was on July 11, right before the OFI vent, alog 79037. After the OFI vent, Camilla noticed that the noise floor around 10 kHz appeared to have reduced, as well as the HOM peak heights, alog 76794. She posted a follow-up comment on that log today noting that the IFO to OMC mode matching could have an effect on those peaks. This could possibly be related to the decrease in frequency noise. Meanwhile, the frequency noise below 100 Hz seems to be about the same as the July measurement. One significant feature in the high frequency portion of the spectrum is a large peak just above 5 kHz. I have a vague memory that this is approximately where a first order mode peak should be, but I am not sure.
There is no significant change in the intensity noise from July, except that there is also a large peak in the intensity noise just above 5 kHz. Gabriele and I talked about this briefly; we think this might be gain peaking in the ISS, but its hard to tell from alog measurements if that's possible. We think that peak is unlikely to be from the CARM loop. We mentioned the ISS theory to Ryan S. on the off-chance it is related to the current PSL struggles.
The other significant change in the noise budget is the change in the LSC noise. The LSC noise has reduced relative to the last noise budget measurement, alog 80215, which was expected from the PRCL feedforward implementation. Looking directly at the LSC subbudget, PRCL has been reduced by a factor of 10, just as predicted from the FF performance. Now, the overall LSC noise contribution is dominated by noise from MICH. Between 10-20 Hz, we might be able to win a little more with a better MICH feedforward, however that is a very difficult region to fit because of various high Q features (reminder alog).
Just as in the previous noise budget, there is a large amount of unaccounted-for noise. The noise budget code uses a quantum model that Sheila and Vicky have been working on extensively, but I am not sure of the status, and how much of that noise could be affected by adjustments to the model. Many of the noisy low frequency peaks also appear very broad on the timescale of the noise budget plot. We could try running over a longer period of time to better resolve those peaks.
Between 100-500 Hz there are regions where the sum of known noises is actually larger than the measured noise. I think this is because the input jitter projections are made using CAL DELTA L, but the overall noise budget is run on CALIB CLEAN where we are running a jitter subtraction.
I believe these couplings were pushed to aligoNB repo in commit bcdd729e.
I reran the jitter noise injections, trying to increase the excitation about 2 kHz to better see the high frequency jitter noise. The results were moderately successful; we could probably push even harder. The results indicate that jitter noise is with a factor of 2-3 of DARM above 1 kHz.
I have attached the updated DARM noise budget and input jitter budget. I'm also attaching the ASC budget (no change expected) just because I forgot to attach it in the previous post.
I added a tag to the locklost tool to tag "IMC" if the IMC looses lock within 50ms of the AS_A channel seeing the lockloss: MR !139. This will work for all future locklosses.
I then ran just the refined time plugin on all NLN locklosses from the emergency break end 2024-08-21 until now in my personal lock loss account. The first lockloss from NLN tagged "IMC" was 2024-09-13 1410300819 (plot here), then got more and more frequent: 2024-09-19, 2024-09-21, then almost every day since the 2024-09-23.
Oli found that we've ben seeing PSL/FSS glitches since before June 80520 (they didn't check before that). The first lockloss tagged FFS_OSCLATION (where FSS_FAST_MON >3 in the 5 seconds before lock loss) was Tuesday September 17th 80366.
Keita and Sheila discussed that on September 12th the IMC gain distribution was changed by 7dB (same output but gain moved from input of board to output): 79998. We think this shouldn't effect the PSL but it could possibly have exasperated the PSL glitching issues. We could try to revert this change if the PSL power chassis swap doesn't help.
On Wednesday 9th Oct the IMC gain redistribution was reverted: 80566. It seems like this change has helped reduce the locklosses from a glitching PSL/FSS but hasn't solved it completely.