IFO is in NLN and OBSERVING as of 11:15 UTC.

IMC/EX Rail/Non-Lockloss Lockloss Investigation:

In this order and according to the plots, this is what I believe happened.

I believe EX saturated, prompting IMC to fault while guardian was in DRMI_LOCKED_CHECK_ASC (23:17 PT), putting guardian in a weird fault state but keeping it in DRMI, without unlocking (still a mystery). Ryan C noticed this (23:32 PT) and requested IMC_LOCK to DOWN (23:38 PT), tripping MC2’s M2 and M3 (M3 first by a few ms). This prompted Guardian to call me (23:39 PT). What is strange is that even after Ryan C successfully put IMC in DOWN, guardian was unable to realize that IMC was in DOWN, and STAYED in DRMI_LOCKED_CHECK_ASC until Ryan C requested it to go to INIT. Only after then did the EX Saturations stop. While the EX L3 stage is what saturated before IMC, I don’t know what caused EX to saturate like this. The wind and microseism were not too bad so this could definitely be one of the other known glitches happening before all of this, causing EX to rail.

Here’s the timeline (Times in PT)

23:17: EX saturates. 300ms later, IMC faults as a cause of this. 

23:32: Ryan C notices this weird behavior in IMC lock and MC2 and texted me. He noticed that IMC lost lock and faulted, but that this didn’t prompt an IFO Lockloss. Guardian was still at DRMI_LOCKED_CHECK_ASC, but not understanding that IMC is unlocked and EX is still railing. 

23:38: In response, Ryan C put IMC Lock to DOWN, which tripped MC2’s M3 and M2 stages. This called me. I was experiencing technical issues logging in, so ventured to site (made it on-site 00:40 UTC).

00:00: Ryan C successfully downed IFO by requesting INIT. Only then did EX stop saturating.

00:40: I start investigating this weird IMC fault. I also untrip MC2 and start an initial alignment (fully auto). We lose lock at LOWNOISE_ESD_ETMX, seemingly due to large sus instability probably from the prior railing since current wind and microseism aren’t absurdly high. (EY, IX, HAM6 and EX saturate). The LL tool is showing an ADS excursion tag.

03:15: NLN and OBSERVING achieved. We got to OMC_Whitening at 02:36 but violins were understandably quite high after this weird issue.

Evidence in plots explained:

Img 1: M3 trips 440ms before M2. Doesn’t say much but was suspicious before I found out that EX saturated first. Was the first thing I investigated since it was the reason for call (I think).

Img 2: M3 and M2 stages of MC2 showing IMC fault beginning 23:17 as a result of EX saturations (later img). All the way until Ryan C downs IMC at 23:38, which is also when the WD tripped and when I was called.

Img 3: IMC lock faulting but NOT causing ISC_LOCK to go to lose lock. This plot shows that guardian did not put IFO in DOWN or cause it to lose lock. IFO is in DRMI_LOCKED_CHECK_ASC but IMC is faulting. Even when Ryan C downed the IMC (which is where the crosshair is), this did not cause a ISC to go to DOWN. The end time axis is when Ryan C put IFO in INIT, finally causing a Lockloss and ending the railing in EX (00:00).

Img 4: EX railing for 42 minutes straight, from 23:17 to 00:00. 

Img 5: Ex beginning to rail 300ms before IMC faults. 

Img 6: EX L2 and L3 OSEMs at the time of the saturation. Interestingly, L2 doesn’t saturate but before the saturation, there is erratic behavior. Once this noisy signal stops, L3 saturates.

Img 7: EX L1 and M0 OSEMs at the time of the saturation, zoomed in. It seems that there is a noisy and loud signal, (possibly a glitch or due to microseism?) in the M0 stage that is very short which may have kicked off this whole thing.

Img 8: EX L1 and M0 OSEMs at the whole duration of saturation. We can see the moves that L1 took throughout the 42 minutes of railing, and the two kicks when the railing started and stopped.

Img 9 and 10: An OSEM from each stage of ETMX, including one extra from M0 (since signals were differentially noisy). Img 9 is zoomed in to try to capture what started railing first. Img 10 shows the whole picture with L3’s railing. I don’t know what to make of this.

Further investigation:

See what else may have glitched or lost lock first. Ryan C’s induced lockloss, saving the constant EX railing doesn’t seem to show up under the LL tool, so this would have to be done in order of likely suspects. I’ve never seen this behavior before what this was if anyone else has.

Other:

Ryan’s post EVE update: alog 81061

Ryan’s EVE Summary: alog 81057

I was about to go to bed when I glanced at the control room screenshots and saw that something looked wrong, verbal was full of MC2 and EX saturations and ETMX drivealign was constantly saturating along with the suspension. I saw ISC_LOCK was also in a weird state, as it thought it was in DRMI_LOCKED_PREP_ASC despite having lost the IMC and both ARMS.

I texted Ibrahim that something didn't look right, I logged in soon after and requested IMC_LOCK to down to stop it which have been a bad move as it tripped the M2 and M3 watchdogs on MC2. After some texts with ibrahim I tried to bring ISC_LOCK to down, had to init it to get it there. Ibrahims taking over now.

TITLE: 11/05 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Wind
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: We've been down from WIND for most of the day, winds are finally below 20mph for the 3 minutes average as of the end of the shift.
LOG:                                                                                                                                                     

PSL/IMC investigations today while we were down for the wind alog81056, the secondary microseism is still decreasing however slowly. Its been a windy shift, I had a ~2ish hour window of >30mph winds where I was able to hold ALS, but I ran into issues at ENGAGE_ASC where we would have an IMC lockloss 13 seconds into the state everytime.

• 02:13 UTC I tried to see if I can hold GREEN_ARMS locked as the wind had calmed down a little
• 03:05 UTC ENGAGE_ASC lockloss, the ISS unlocked, IMC and ASC lost it at the same time. Screenshot
  • tags: REFINED, IMC, ADS_EXCURSION, WINDY, SOFT_LIMITER
• 03:21 UTC ENGAGE_ASC lockloss, I paused for 30 seconds at the end of PREP_ASC, same thing IMC and ASC lost it at the same time. Screenshot
  • Same tags, same exact spot 13 seconds into the state when the ASC loops start working
• 03:30 UTC the winds picking back up
• 03:47 UTC ENGAGE_ASC lockloss, I waited 5 minutes in PREP_ASC this time, same result
  • Same tags
• 03:59 UTC SHUTTER_ALS lockloss from DRMI unlocking, FSS_FAST_MON stepped up and NPRO_TEMP stepped down, screenshot
• 04:30 UTC Struggling to hold the arms and drmi, I want to run an IA but with the wind back above 30mph thats probably not the best idea
• 05:00 UTC Going to DOWN as ALS can't hold for more than a minute with the winds

• 21:37 -> 23:37 UTC - Leaving IMC locked and ISS first loop unlocked for testing (~2 hours, gps_start = 1414791485, gps_stop = 1414798720)
  • IMC & FSS stayed locked the whole time
• 23:38 -> 01:38 UTC- Adding in ISS first loop (~2 hours gps_start =  1414798725, gps_stop = 1414805900)
  • IMC & FSS lost lock a few times, the ISS lost lock many times, in a few different combinations
    • ISS and IMC lose lock, but FSS stays locked
      • The first lockloss looked like the ISS_AOM and FSS_TPD were the first to see it (at the same time)
      • The FSS stays locked through a lot of these ISS oscillations that knock out the IMC and ISS, another example
    • The ISS would lose it while the IMC is relocking with the FSS staying locked, example
    • All 3 would lose lock, ISS first then IMC then FSS, example
    • Only the ISS would lose lock, example
    • All 3, IMC, then ISS then FSS example

TITLE: 11/05 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Wind
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 32mph Gusts, 18mph 3min avg
    Primary useism: 0.09 μm/s
    Secondary useism: 0.51 μm/s
QUICK SUMMARY:

• We've been down due to the wind for most of the day, we've been running some test to find the source of the FSS issues
  • Trying to hold IMC lock with and without the ISS first loop
• Windy.com predicts the wind storm will peak around 4-5pm PST (00-01 UTC), and calm down around the end of the shift, 10-11pm PST (06-07 UTC)
• 2ndary microseism is decreasing, its just below the 90th percentile

TITLE: 11/04 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Environment - Wind
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: H1 has been down all shift due to high microseism for the first half of the day and high winds for the second. Meanwhile, we've been able to continue glitch investigations with the PSL/IMC from alog80990. We sat with the IMC locked and ISS off for 2 hours starting at 21:37 and saw no fast glitches (trend in first attachment, white background). After turning the ISS back on, things were calm for a while before the IMC lost lock at 23:54 (second attachment, black background). There were three more IMC locklosses within 10 minutes of this, but things have been steady again since.

• 15:30 - H1 down, starting initial alignment
• 16:12 - IA finished, starting lock acquisition
• 17:55 - No success in locking; H1 to IDLE for power cycle of h1psl0 and card swaps (alog81048)
• 20:38 - Chassis work finished, starting lock acquisition
• 21:24 - Wind too high to keep arms locked, holding in PREP_FOR_LOCKING
  • 21:37 - Leaving IMC locked and ISS first loop unlocked for testing
  • 23:38 - Adding in ISS

LOG:

This alog is a continuation of previous efforts to correctly calibrate and compare the LSC couplings between Hanford and Livingston. Getting these calibrations right has been a real pain, and there's a chance that there could still be an error in these results.

These couplings are measured by taking the transfer function between DARM and the LSC CAL CS CTRL signal. All couplings were measured without feedforward. The Hanford measurements were taken during the March 2024 commissioning break. The Livingston MICH measurement is from Aug 29 2023 and the PRCL measurement from June 23 2023.

As an additional note, during the Hanford MICH measurement, both MICH and SRCL feedforward were off. However, for the Livingston MICH measurement, SRCL feedforward was on. For the PRCL measurements at both sites, both MICH and SRCL feedforward were engaged.

Results:

The first plot attached shows a calibrated comparison between the MICH, PRCL and SRCL couplings at LHO.

The second plot shows a calibrated comparison between the Hanford and Livingston MICH couplings. I also included a line indicating 1/280, an estimated coupling level for MICH based on an arm cavity finesse of 440. Both sites have flat coupling between about 20-60 Hz. There is a shallow rise in the coupling above 60 Hz. I am not sure if that's real, or some artifact of incorrect calibration. The Hanford coupling below 20 Hz has steeper response, which appears like some cross coupling between SRCL perhaps (it looks about 1/f^2 to me). Maybe this is present because SRCL feedforward was off.

The third plot shows a calibrated comparison between the Hanford and Livingston PRCL couplings. I have no sense of what this coupling should look like. If the calibration here is correct, this indicates that the PRCL coupling at Hanford is about an order of magnitude higher than Livingston. Whatever coupling is present has a different response between both sites, so I don't really know what to make of this.

Calibration notes:

The Hanford measurements used H1:CAL-DELTAL_EXTERNAL_DQ and the darm calibration from March 2024 (/ligo/groups/cal/H1/reports/20240311T214031Z/deltal_external_calib_dtt.txt)

The Livingston measurement used L1:OAF-CAL_DARM_DQ and a darm calibration that Dana Jones used in her previous work (74787, saved in /ligo/home/dana.jones/Documents/cal_MICH_to_DARM/L1_DARM_calibration_to_meters.txt)

LHO MICH calibration: I updated the CAL CS filters to correctly match the current drive filters. However, I made the measurement in March 11 before catching some errors in the filters. I incorrectly applied a 200:1 filter, and multiplied by sqrt(1/2) when I should have multipled by sqrt(2) (76261). Therefore, my calibration includes a 1:200 filter and a factor of 2 to appropriately compensate for these mistakes. Additionally, my calibration includes a 1e-6 gain to convert from um to m, and an inverted whitening filter [100, 100:1, 1]. This is all saved in a DTT template: /ligo/home/elenna.capote/LSC_calibration/MICH_DARM_cal.xml

LLO MICH calibration: I started with Dana Jones' template (74787), and copied it over into my directory: /ligo/home/elenna.capote/LSC_calibration/LLO_MICH.xml. I inverted the whitening filter using [100,100,100,100,100:1,1,1,1,1] and applied a gain of 1e-6 to convert um to m.

LHO PRCL calibration: I inverted the whitening using [100,100:1,1] and converted from um to m with 1e-6.

LLO PRCL calibration: I inverted the whitening using [10,10,10:1,1,1] and converted from um to m with 1e-6.

I exported the calibrated traces to plot myself. Plotting code and plots saved in /ligo/home/elenna.capote/LSC_calibration

Mon Nov 04 10:10:29 2024 INFO: Fill completed in 10min 26secs

WP12186

Richard, Fil, Erik, Dave:

We performed a complete power cycle of the h1psl0. Note, this is not on the Dolphin fabric so no fencing was needed. Procedure was

• Stop all models and power down h1psl0 computer
• Power down IO Chassis, all AA chassis and all AI chassis.
• Wait for a minute
• Power up AA chassis and IO Chassis (keep AI's off)
• Power up h1psl0 computer, wait for models to start
• Finally, power up AI chassis.

The system was power cycled at 10:11 PDT. When the iop model started, it reported a timing error. The duotone signal (ADC0_31) was a flat line signal of about 8000 counts with a noise of a few counts.

Erik thought the timing card had not powered up correctly, so we did a second round of power cycles at 10:30 and this time the duotone was correct.

NOTE: the second ADC failed its AUTOCAL on both restarts. This is the PSL FSS ADC.

If we continue to have FSS issues, the next step is to replace the h1pslfss model's ADC and 16bit DAC cards.

[   45.517590] h1ioppsl0: INFO - GSC_16AI64SSA : devNum 0 : Took 181 ms : ADC AUTOCAL PASS
[   45.705599] h1ioppsl0: ERROR - GSC_16AI64SSA : devNum 1 : Took 181 ms : ADC AUTOCAL FAIL
[   45.889643] h1ioppsl0: INFO - GSC_16AI64SSA : devNum 2 : Took 181 ms : ADC AUTOCAL PASS
[   46.076046] h1ioppsl0: INFO - GSC_16AI64SSA : devNum 3 : Took 181 ms : ADC AUTOCAL PASS

C. Compton, R. Short

I've updated the PSL_FSS Guardian so that it won't jump into the FSS_OSCILLATING state whenever there's just a quick glitch in the FSS_FAST_MON_OUTPUT channel. Whenever the FSS fastmon channel is over its threshold of 0.4, the FSS_OSCILLATION channel jumps to 1, and the PSL_FSS Guardian responds by dropping the common and fast gains to -10 dB then stepping them back up to what they were before. This is meant to catch when there's a servo oscillation in the FSS, but it's also been happening when the FSS glitches. Since moving the gains around makes it difficult for the IMC to lock, the Guardian should now only do that when there's an actual oscillation and should save time relocking the IMC.

FAMIS 31058

Trends are all over the place in the last 10 days due to several incursions, but I motsly tried to focus on how things have looked since we brought the PSL back up fully last Tuesday (alog80929). Generally things have been fairly stable, and at least for now, I dn't see the PMC reflected power slowly increasing anymore.

TITLE: 11/04 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 28mph Gusts, 19mph 3min avg
    Primary useism: 0.07 μm/s
    Secondary useism: 0.56 μm/s
QUICK SUMMARY: H1 has been sitting in PREP_FOR_LOCKING since 08:05 UTC. Since the secondary microseism has been slowly decreasing, I'll try locking H1 and we'll see how it goes.

• Wind gusts moderate, microseism around 90th percentile
• All other systems nominal

TITLE: 11/04 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Microseism, LOCK_ACQUISITION
INCOMING OPERATOR: Corey
SHIFT SUMMARY:

We spent most of the day with the secondary microseism mostly above the 90th percentile, it started to decrease ~8 hours ago but still remains about half above the 90th percentile. The elevated microseism today is from both the storms by Greenland and the Aleutians as seen by the high phase difference for both the arms with the corner station (bottom plot).

We keep losing it at the beginning of LOWNOISE_ESD_ETMX, I see some ASC ringups on the top of NUC29 (CHARD_P I think?), no FSS glitches before the locklosses, no tags on the lockloss tool besides WINDY. It's always a few seconds into the run method, I was able to avoid this by slowly stepping through some of the higher states (PREP_ASC, ENGAGE_ASC, MAX_POWER, LOWNOISE_ASC). I'm not sure which of these is the most relevent to not see the ringup, probably not the ASC states as when I paused there but forgot MAX_POWER I still saw the ringup.

LOG: No log.

• 00:53 UTC LOWNOISE_ESD_ETMX lockloss
• 01:57 UTC LOWNOISE_ESD_ETMX lockloss
  • These both had similar behavior to what Corey saw here alog80720 and TJ here alog80954
• 02:44 UTC MAX_POWER lockloss (did not ring up the violins luckily)
  • IMC lost it at the same time as ASC, FSS_FAST channel starting growing ~7 seconds before the LL
  • Over a dozen IMC locklosses trying to get to GREEN_ARMS
• 03:30 UTC LOWNOISE_ESD_ETMX lockloss
  • I tried stepping a little slower through some of the states leading up to it (PREP and engage ASC), I was going to also pause in MAX POWER but I accidentally moved it on
• 04:00 UTC PREP_DC_READOUT_TRANSITION lockloss
  • IMC and ASC lost it at the same time, some small FSS glitches starting ~350ms before the LL
  • PSL-FSS_AUTOLOCK_STATE moved ~20 ms before ASC
• 04:41 UTC lockloss TRANSITION_FROM_ETMX
  • Things were looking great (The ASC signals mainly), I had paused for 30-45 seconds after PREP_ASC and ENGAGE_ASC, then I waited 60 seconds after MAX_POWER and another 60 seconds after LOWNOISE_ASC finished
  • ASC lost it 150ms before IMC, I did not see any ASC ringups this time (IMC_REFL_SERVO_SPLITMON ran away?)
• 05:38 UTC TRANSITION_FROM_ETMX lockloss, lost it at a different spot in the run method than before
  • No ASC ringup, ASC lost it ~100ms before IMC

 Most of the locklosses over this weekend have the IMC tag and those do show the IMC losing lock at the same time as AS_A, but since I don't have any further insight into those, I wanted to point out a few locklosses where the causes are different from what we've been seeing lately.

2024-11-02 04:17UTC

• No IMC tag, does have a DCPD tag
• Everything looking normal, then 100ms before the lockloss is first seen by anyone, PSL-ISS_AOM_DRIVER_MON_OUT shows a steep drop in value, getting larger in amplitude until the lockloss (ndscope1, ndscope2)

2024-11-02 17:13 UTC

• No IMC tag, does have a DCPD tag
• Everything looking normal, then 1s before the lockloss is first seen by anyone, PSL-ISS_AOM_DRIVER_MON_OUT shows a steep drop in value, getting larger in amplitude until the lockloss (ndscope3, ndscope4)
• Very similar to the above example, except the glitch isn't as steep. There is another one of these glitches that happens a few seconds before, but that one is even less steep and it is able to catch itself

2024-11-02 18:38:30.844238 UTC

• No IMC tag, does have a DCPD tag
• Small glitch in the FSS FASTMON channel caused NPRO temperature to spike and NPRO power jumps down, then ISS AOM DRIVERMON sees glitch up to the lockloss start (ndscope5, ndscope6-zoomed into FSS drop)

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.