Woke up to see that the SQZ_OPO_LR Guardian had the message:

"disabled pump iss after 10 locklosses. Reset SQZ-OPO_ISS_LIMITCOUNT to clear message"

Followed 73053, but did NOT need to touch up the OPO temp (it was already at its max value); then took SQZ Manager back to FRE_DEP_SQZ, and H1 went back to OBSERVING.

TITLE: 06/14 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Quiet shift with H1 locked and observing for the duration. There was one errant Picket Fence trigger (see midshift log) and we rode out a M5.9 EQ from the southern Atlantic, but otherwise uneventful. H1 has now been locked for 11 hours.
LOG: No log for this shift.

State of H1: Observing at 157Mpc, locked for 6.5 hours.

Quiet shift so far except for another errant Picket Fence trigger to EQ mode just like ones seen last night (alog78404) at 02:42 UTC (tagging SEI).

SheilaD, FranciscoL, ThomasS [Remote: LouisD]

Today, we tried to evaluate the effect on H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT from changing H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN. In summary, we were not able to collect enough data and we want to do this again with a quiet IFO.

We used the script KappaToDrivealign.py to change the value of H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN. The script worked as intended but has to round off the the value that it uses to change the drivealign to the digits that EPICS can take. H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN changed from 184.65 to 186.53576 (1.012%). We are chainging the gain to reduce the difference of the model of the actuation function and the measurement of \DeltaL_{res}. We did not change H1:CAL-CS_DARM_FE_ETMX_L3_DRIVEALIGN_L2L_GAIN because that would have a net-zero change between measurement and model. We were not able to assess the effect of our change at the end of the commissioning period so we reverted our changes.

kappa_tst_crossbar.png shows a trend of the channels we are concerned of. The crossbar on KAPPA_TST shows that the value drops closely after the gain of DRIVEALIGN_L2L was reverted. However, the uncertainty from H1:CAL-CS_TDEP_PCAL_LINE3_UNCERTAINTY increased during these values, which makes them less reliable. The data between the vertical dashed lines on KAPPA_TST from kappa_tst_deltat.png shows that there was a period of time at which KAPPA_TST was closer to 1 along with a lower uncertainty of PCAL_LINE3.

There are two ways we could repeat this measurement: With 25 minutes of quiet time of the interferometer, we can monitor the changes of KAPPA_TST after changing DRIVEALIGN_L2L gain *or* we can measure simulines before and after changing DRIVEALIGN_L2L. The latter method would illustrate better the sability of the UGF, but it would take around 40 minutes.

To recap the data we collected today was not reliable enough because it had a high uncertainty and it was not enough time to clearly see the effect of our changes. We will try again by either monitoring KAPPA_TST or running simuline measurements.

• O4b so far = 110 locklosses / 925 hours =  1 lockloss per 9 hours in Observing
• O4a = 350 locklosses / 5700 hours = 1 lockloss per 16 hours in Observing
• O3b = 247 locklosses / 2790 hours = 1 lockloss per 11 hours in Observing
• O3a = 182 locklosses / 3120 hours = 1 lockloss per 17 hours in Observing

I've also looked at the amount of hours we've lost from unknown locklosses, which is the majority of our locklosses at around 65%, and how many theortircal GW's we coudl ahev missed becasue of these. 

O4b so far 110 LHO locklosses from observing in O4b [1] x 65% unknown [2] x 2 hours down per lockloss = 143 hours downtime from unknown locklosses. 925 observing hours in O4b so far (60% of O4b [3], from April 10th).

O4a 350 LHO locklosses from observing in O4a [1] x 65% unknown [2] x 2 hours down per lockloss = 450 hours downtime from unknown locklosses. 5700 observing hours in O4a (67% of O4a [3]) with 81 candidates  in O4b [4]= 1 candidate / 70 hours so 450 hours / 70 observing hours per candidate ~ 6.5 gw candidates lost due to unknown locklosses The Ops team notes that we had considerably more locklosses during the first ~month of O4a while using 75W input power.

O3b 247 LHO locklosses from observing in O3b [5] x 65% unknown [using same as O4a] x 2 hours down per lockloss = 320 hours downtime from unknown locklosses. 2790 observing hours in O4a (79% of O3b [3]) with 35 events [6]= 1 events / 80 hours 320 hours / 80 observing hours per event ~ 4 events lost due to unknown locklosses.

O3a 182 LHO locklosses from observing in O3a [5] x 65% unknown [using same as O4a] x 2 hours down per lockloss = 235 hours downtime from unknown locklosses. 3120 observing hours in O4a (71% of O3a [3]) with 44 events [6]= 1 events / 70 hours 235 hours / 70 observing hours per event ~ 3.3 events lost due to unknown locklosses.

We currently don't track downtime per lockloss, but we could think about tracking it, 2 hours is a guess. It may be as low as 1 hour. 

TITLE: 06/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: Commissioning and calibration this morning, followed by a lock loss. Relocking was not automated for two things: touched ETMX Y by 0.3urads and it caught, then PRM to avoid an initial alignment and get PRMI to lock. Locked for 2 hours now.
LOG:

• 1932 Observing
• 1948 Lock loss
• 2107 Observing
• 2202-2206 Dropped observing, SQZ lost lock

For operators: I put back in the MICH Fringes and PRMI flags that Sheila and company put to False (no auto MICH or PRMI) last weekend (alog78319). So it should try MICH and PRMI on its own again.

TITLE: 06/13 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 6mph Gusts, 4mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.09 μm/s
QUICK SUMMARY: H1 has been locked and observing for 2 hours; things are running smoothly after the commissioning window earlier today.

• Environment is calm
• All other systems nominal

Naoki, Andrei, Camilla, Vicky

To investigate the effect of vacuum pressure incident in HAM6 reported in 78346, Peter suggested to measure the FC loss since the FC should be the most sensitive cavity. We tried the FC ringdown measurement, but the result does not make any sense. We will take the data again.

Previous ringdown measurement: 66403, 67273

For ringdown measurement, we need the cabling as written in 67409 to lock the FC green with SQZ laser VCO since the SQZ laser frequency noise is too much for ringdown measurement with only TTFSS. We did only the first and second cabling in 67409. The third and fourth cabling is necessary if you want to do homodyne measurement.

After the cabling, we requested OPO guardian to LOCKED_SEED_DITHER, but the dither lock did not work well. The seed stayed around 25% of maximum seed trans. We confirmed that the OPO CMB EXC is connected to some DAC output which should be dither signal. Although the seed is not on resonance of OPO, the seed power seems stable so we moved on.

Then we manually locked the FC green. We also engaged one boost of FC green CMB. We adjusted green VCO tune to get the seed on resonance of FC. 

We increased the seed power to 2.7 mW. More than 2.7 mW seed saturated the FC trans IR PD.

We looked at H1:SQZ-FC_TRANS_D_LF_OUT and H1:SQZ-OPO_IR_PD_LF_OUT for FC TRANS and REFL since they are 16k channel. We maximized the seed FC trans by adjusting green VCO tune and requested OPO guardian to DOWN.

The attached figure shows the ringdown measurement. The decay time of FC TRANS and REFL are quite different and both of them are much larger than the expected 4 ms decay time. Also the decay start timing is different for TRANS and REFL. The decay of FC TRANS is not going to 0, which means there would be residual seed. The requesting OPO guardian to DOWN might not block the seed enough and this might be related to the dither locking, which is not working well.

EDIT: There is an elliptic low pass filter LP100 in FC trans IR PD, which would explain the different behavior of TRANS and REFL. We should turn off LP100 for ringdown measurement.

Bees are again nesting in a wire spool on the outdoor shelf by the corner station.

I took the script that we have been using to run our A2L and converted it to run the measurements for all quads and degrees of freedom at the same time, or less, as desired. The new script is (userapps)/isc/h1/scripts/a2l/a2l_min_multi.py. Today Sheila and I tested it for all quads with just Y with the results below. These values were accepted in SDF, updated in lscparams.py, and ISC_LOCK reloaded. More details about the script at the bottom of this log.

Results for ETMX Y
Initial:  4.99
Final:    4.94
Diff:     -0.04999999999999982

Results for ETMY Y
Initial:  0.86
Final:    0.94
Diff:     0.07999999999999996

Results for ITMX Y
Initial:  2.93
Final:    2.89
Diff:     -0.040000000000000036

Results for ITMY Y
Initial:  -2.59
Final:    -2.51
Diff:     0.08000000000000007

The script we used to use was (userapps)/isc/common/scripts/decoup/a2l_min_generic_LHO.py which was, I think, originally written by Vlad B. and then Jenne changed it up to work for us at LHO. I took this and changed a few things around to then call the optimiseDOF function for each desired quad and dof under a ThreadPool class from multiprocess to run all of the measurements simultaneously. We had to move or change filters in the H1:ASC-ADS_{PIT,YAW}{bank#}_DEMOD_{SIG, I, Q} banks so that each optic and dof is associated with a particular frequency and used the ADS banks 6-9. These frequencies needed to be spaced apart enought but still within our area of interest. We also had to engage notches for all of these potential lines in the H1:SUS-{QUAD}_L3_ISCINF_{P,Y} banks (FM6&7). We also accepted the ADS output matrix values in SDF for these new banks with a gain of 1.

This hasn't been tested for all quads and both P&Y, so far only Y.

ETMX sees an odd move ~100ms before the lock loss just like yesterday. The lock loss tool also has a DCPD tag.

Observing at 1932UTC. A bit of a delay wrapping up commissioning today, but we're back to observing and locked for 20 hours.

Jennie W, Keita, Sheila

Sheila suggested we move SRM to increase the coupled cavity pole as this got worse in the previous week.

Keita and I opened the SRC1_P and SRC1_Y loops (and turned off the offsets) then walked SRM in yaw and looked at the coupled cavity pole.

See image of the loop medm screen.

Its hard to see but moving down in SRM yaw on the sliders made the f_cc higher. We stopped due to the end of the commissioning period so maybe we could do more optimisation of this.

See the attached trend.

I set the offsets in the two loops to cancel out the INMON values at this new alignment, before closing them again.

These offsets have been changed in lscparams.py on lines 551 and 552 and accepted in OBSERVE.snap by TJ.

Robet mentioned while he was here that there was coherence with the ground current clamp in the vertex and DARM, and suggested that we try having both ITM biases set to 0V.  I did that today, and accepted the bias gain of 0 in OBSERVE and SAFE.snaps.

Robert also found that we need to change the bias at EX, which we haven't done yet.

I ran the DARM offset step code starting at:

2024 Jun 13 16:13:20 UTC (GPS 1402330418)

Before recording this time stamp it records the PCAL current line settings and makes sure notches for 2 PCAL frequencies are set in the DARM2 filter bank.

It then puts all the PCAL power into these lines at 410.3 and 255Hz (giving them both a height of 4000 counts), and measures the current DARM offset value.

It then steps the DARM offset and waits for 120s each time.

The script stopped at 2024 Jun 13 16:27:48 UTC (GPS 1402331286).

In the analysis the PCAL lines can be used to calculate how the optical gain changes at each offset.

See the attached traces, where you can see that H1:OMC-READOUT_X0_OFFSET is stepped and the OMC-DCPD_SUM and ASC-AS_C respond to this change.

Watch this space for analysed data.

The script sets all the PCAL settings back to nominal after the test from the record it ook at the start.

The script lives here:

/ligo/gitcommon/labutils/darm_offset_step/auto_darm_offset_step.py

The data lives here:

/ligo/gitcommon/labutils/darm_offset_step/data/darm_offset_steps_2024_Jun_13_16_13_20_UTC.txt

Ran the usual broadband and simulines sweep starting at 1538UTC.

Simulines start:

PDT: 2024-06-13 08:46:11.048813 PDT
UTC: 2024-06-13 15:46:11.048813 UTC
GPS: 1402328789.048813

Simulines end:
PDT: 2024-06-13 09:07:41.142373 PDT
UTC: 2024-06-13 16:07:41.142373 UTC
GPS: 1402330079.142373
 

Files:

024-06-13 16:07:41,052 | INFO | File written out to: /ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOLG_SS_20240
613T154612Z.hdf5
2024-06-13 16:07:41,060 | INFO | File written out to: /ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCALY2DARM_SS
_20240613T154612Z.hdf5
2024-06-13 16:07:41,066 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUSETMX_L1_SS
_20240613T154612Z.hdf5
2024-06-13 16:07:41,071 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUSETMX_L2_SS
_20240613T154612Z.hdf5
2024-06-13 16:07:41,076 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUSETMX_L3_SS
_20240613T154612Z.hdf5

On Friday 06/07/2024 Dave Barker sent an email to the vacuum group noting 3 spikes on the pressure of the main vacuum envelope, I took a closer look at the 3 different events and noticed that the events correlated to the IFO losing lock.  I contacted Dave, and together we contacted the operator, Corey, who made others aware of our findings.

The pressure "spikes" were noted by different components integral to the vacuum envelope.  Gauges noted the sudden rise on pressure, and almost at the same time ion pumps reacted to the rise on pressure.  The outgassing was noted on all stations, very noticeable a the mid stations, and with less effect at both end stations, and for both with a delay.

The largest spike for all 3 events is noted at HAM6 gauge, we do not have a gauge at HAM5 or HAM4.  The one near HAM6 is the one on the relay tube that joins HAM5/7 (PT152), with the restriction of the relay tube, then the next gauge is at BSC2 (PT120), however the spike is not as "high" as the one noted on HAM6 gauge.

A list of aLOGs made by others related to the pressure anomalies and their findings:
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=78308
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=78320
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=78323
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=78343

Note: the oscillation visible on the plot of the outer stations (Mids and Ends) is the diurnal cycle, nominal behavior.

Jennie W, Sheila

Sheila wanted me to look at how good our optical gain is doing since the burn on the OFI that roughly happened (we think) on the 22nd April.

Before this happened we made a measurement of the OMC alignment using dithers on the OMC ASC degrees of freedom. We got a set of new alignment offsets for the OMC QPDs that would have increased our optical gain but did not implement these at the time.

After the OFI burn we remeasured these alignment dithers and found a similar set of offsets that would imrpove our optical gain. Thus I have assumed that we would have achieved this optical gain increase before the OFI burn if we had implemented the offset changes then.

Below is the sequence of events then a table stating our actual or inferred optical gain and the date on which it was measured.

Optical gain before vent as tracked by kappa C: 2024/01/10 22:36:26 UTC is 1.0117 +/- 0.0039

Optical gain after vent: 2024/04/14 03:54:38 UTC is 1.0158 +/- 0.0028, optical gain if we had improved OMC alignment = 1.0158 + 0.0189 = 1.0347

SR3 yaw position and SR2 yaw and pitch positions were changed on the 24th April ( starting 17:18:15 UTC time) to gain some of our throughput back.

The OMC QPD offsets were changed on 1st May (18:26:26 UTC time) to improve our optical gain - this improved kappa c by 0.0189.

Optical gain after spot on OFI moved due to OFI damage: 2024-05-23 06:35:25 UTC 1.0051 +/- 0.0035

SR3 pitch and yaw positions and the SR2 pitch and yaw positions were changed on 28th May (starting at 19:14:34 UTC time).

SR3 and SR2 positions moved back to pre-28th values on 30th May (20:51:03 UTC time).

So we still should be able to gain around 0.0296 ~ 3% optical gain increase, provided we stay at the spot on the OFI we had post 24th April:

SR2 Yaw slider = 2068 uradians
SR2 Pitch slider = -3 uradians

SR3 Yaw slider = 120 uradians

SR3 Pitch slider = 438 uradians