TITLE: 10/19 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 31mph Gusts, 16mph 3min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.37 μm/s 
QUICK SUMMARY:

IFO is LOCKING at ENGAGE_SOFT_LOOPS

IFO was in the middle of an automatic relock when I arrived. Wind was very high last night but looks to be coming down.

Should be able to go into OBSERVING soon.

TITLE: 10/19 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Overall a fairly quiet shift. After an unknown lockloss earlier this evening, I ran H1 through an alignment and it was able to relock fully on its own. H1 has been locked since, now for 3.5 hours.
LOG:

• 00:06 - Lockloss - alog87558
• 00:27 - Starting initial alignment
• 00:47 - Alignment finished, starting lock acquisition
• 01:37 - Observing

Lockloss @ 00:06 UTC after almost 9 hours locked - link to lockloss tool

No obvious cause.

Ibrahim and Sheila saw yesterday a lockloss after just 9 minutes in Nominal Low Noise from CSOFT_P ringing up at 1 Hz, and we again had one overnight at 05:21 UTC (can't link to online lockloss tool since it was down at the time). In both cases, the IFO had been down for several hours beforehand. After the ASC lockloss last night, the IFO relocked within an hour on its own and this CSOFT ringup did not; see first ndscope screenshot of the comparison between these two times. At the start of the third lock stretch overnight, after the IFO was only down for just under 3 hours, CSOFT_P did ring up the same amount of time into Nominal Low Noise, but this time it did not cause a lockloss and eventually calmed back down; see second screenshot. At the start of this lock stretch, after the IFO was down for under 2 hours, CSOFT_P did not seem to ring up at all; see third screenshot. This suggests to me that with a warmer IFO, CSOFT_P doesn't seem to ring up as much at low noise.

The history of this ringup and the last time we changed the CSOFT_P gain can be seen in alog85649. Sheila suggests if we see this ringing up again, we can try bumping the CSOFT_P gain up from 25 to 30. 

TITLE: 10/18 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY:

IFO is in NLN and OBSERVING

We have been observing for the whole day.

Acquired lock at 19:10 UTC and H1 was thermalized by the time we had to run the weekly calibration sweep, which ran successfully. Alog 87553.

Range has been consistent and comparable with last few days but seems low in the low frequency range compared to 2 weeks ago. Ryan S is investigating this.

LOG:

TITLE: 10/18 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 6mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.47 μm/s 
QUICK SUMMARY: H1 has been locked for 7.5 hours. Range is a bit lower than usual; I'll run a range comparison in a bit.

• Wind is low, microseism still high around 90th percentile
• All other systems nominal

Saturday standard coordinated calibration sweep

BB Start: 1444847709

BB End: 1444848020

Simulines Start: 1444848233

Simulines End: 1444849630

2025-10-18 19:06:16,282 | INFO | Finished gathering data. Data ends at 1444849593.0
2025-10-18 19:06:16,498 | INFO | It is SAFE TO RETURN TO OBSERVING now, whilst data is processed.
2025-10-18 19:06:16,498 | INFO | Commencing data processing.
2025-10-18 19:06:16,498 | INFO | Ending lockloss monitor. This is either due to having completed the measurement, and this functionality being terminated; or because the whole process was aborted.
2025-10-18 19:06:52,301 | INFO | File written out to: /ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOLG_SS_20251018T184336Z.hdf5
2025-10-18 19:06:52,309 | INFO | File written out to: /ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCALY2DARM_SS_20251018T184336Z.hdf5
2025-10-18 19:06:52,314 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUSETMX_L1_SS_20251018T184336Z.hdf5
2025-10-18 19:06:52,319 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUSETMX_L2_SS_20251018T184336Z.hdf5
2025-10-18 19:06:52,324 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUSETMX_L3_SS_20251018T184336Z.hdf5
PDT: 2025-10-18 12:06:52.452839 PDT
UTC: 2025-10-18 19:06:52.452839 UTC
 

CALIBMONITOR attached (took screenshot after requesting NLN_CAL_MEAS - might be a mistake but do not know)

Sat Oct 18 10:10:10 2025 INFO: Fill completed in 10min 6secs

TITLE: 10/18 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 3mph Gusts, 0mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.54 μm/s 
QUICK SUMMARY:

IFO is in ENGAGE_ASC_FOR_FULL_IFO

Got in, H1 was locking after an auto initial alignment.

It seems that the wind has died down but that the microseism is still high without signs of coming down. POP and PWR signals look unstable due to microseism. Hoping to get locked today.

TITLE: 10/18 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Wind
INCOMING OPERATOR: Tony
SHIFT SUMMARY: After the wind and microseism died down a bit, I attempted to lock H1 to moderate success. I did not run an alignment, but instead ran through a round of MICH_FRINGES and PRMI in order to lock DRMI. There were a few locklosses along the way I originally attributed to still not great environmental conditions. Eventually, there started being locklosses at the same place in CARM_OFFSET_REDUCTION, specifically when the TR CARM offset was lowered from -12 to -40 (I even verified this by going line-by-line through the state after realizing). After finally remembering that this can happen due to poor arm alignment relative to each other, I started an initial alignment, which ran automatically. Once relocking after that alignment, H1 made it through CARM_OFFSET_REDUCTION without issue. H1 is continuing to relock automatically after that, currently up to MAX_POWER.
LOG:

• 01:26 - Starting relocking attempts
  • 02:08 - Lockloss in CHECK_AS_SHUTTERS
  • 02:21 - Lockloss in CARM_OFFSET_REDUCTION
  • 02:33 - Lockloss in CARM_OFFSET_REDUCTION
  • 02:49 - Lockloss in CARM_OFFSET_REDUCTION (I probably should have noticed something around here)
  • 03:02 - Lockloss in CARM_OFFSET_REDUCTION
  • 03:13 - Lockloss in CARM_OFFSET_REDUCTION
  • 03:31 - Lockloss in CARM_OFFSET_REDUCTION
  • 03:47 - Lockloss while stepping through CARM_OFFSET_REDUCTION
  • 04:02 - Lockloss in ENGAGE_DRMI_ASC (maybe unrelated)
• 04:03 - Starting initial alignment
• 04:27 - Alignment finished, starting lock acquisition

FAMIS 27428, last checked in alog87417

All fans look to be well within acceptable noise range and behavior is largely unchanged compared to last week.

TITLE: 10/17 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Wind
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY:

IFO is in IDLE due to MICROSEISM

Nature has not been good to Hanford today.

90%+ microseism and 40 mph gusts of wind have preventing locking.

We've been abl;e to get past DRMI with some ops intervention (PRM and BS touching in PRMI).

21:00 UTC to 21:09 UTC OBSERVING - We were able to lock for a whole 9 minutes but had a Lockloss due to the 1Hz ringup (alog 87547)

After losing lock, the microseism started trending down (yay!) but the wind speed started increasing rapidly (no!) so we are no unable to lock ALS. Thus, we are sitting IDLE after 5+ failed ALS attempts.

Relevant alogs:

PRMI to MICH timer reduction (alog 87540)

IMC Request Gain Scaling (alog 87545, alog 86744)

LOG:

Known 1Hz ringup lockloss but did not come down as it usually does. Sheila floated increase CSOFT P Gain a further 5 from 25 to 30, but we didn't end up doing this.

TITLE: 10/17 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Microseism
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 40mph Gusts, 24mph 3min avg
    Primary useism: 0.20 μm/s
    Secondary useism: 0.39 μm/s 
QUICK SUMMARY: H1 is currently down after a tough day of locking. Sounds like environmental conditions (mainly microsesm and wind) are causing difficulties with getting H1 back up, and I'll be on the lookout for the strange 1Hz ringup from earlier today.

• Microseism is working its way down, wind is high
• All other systems nominal

Since the power outage where the IMC throughput was reduced, our power normalization has been reducing gains artificially by scaling with the IMC input power, which has increased now to give us the same input power on PRM.  

This is the reason for the apparent change in optical gain, which Elenna noted in 87453 isn't a real change in optical gain in mA/m, but it is a real change in optical gain in DARM ERR counts per meter.  At 2W, the IMC throughput is about the same as it was before the vent since power in the EOM is reduced, the gain scaling that happens in OMC_LOCK and PREP_DC_READOUT aren't much impacted by the power outage.  However, as we power up the interferometer the IMC throughput drops, and we scale gains by the IMC input power request.  This means that we are reducing our loop gains as the IMC throughput drops.  

This power scaling impacts all of our LSC loops, and ASC loops, and would drop all those gains by 3% (60/62).  

This power scaling is done by the laser power guardian, I've added a variable called power_channel that is used everywhere that the power scale is set, and for now I've changed it to 'IMC-IM4_TRANS_NSUM_OUTMON'.   I did not change the channel that is used to check if the rotation stage is giving the requested power, that will still be the IMC input power.  This means that the bootstrapping to adjust the rotation stage should continue to give us the same requested power that it did in the past, and should work even when the IMC is unlocked. 

This should cause an increase in kappa C relative to the calibration that Elenna pushed yesterday.  87520  

If we switch to the IM4 trans channel for this scaling, we will increase all the loop gains by 5% compared to how they were before the power outage.  It might make sense to do this, and add those factors into the loops gains to correct, so that our power scaling is more accurate in the future.  I don't want to do this now since we are having locking difficulties due to microseism and the 1Hz ring up today.  

Fri Oct 17 10:08:33 2025 INFO: Fill completed in 8min 30secs

Jordan confirmed a good fill curbside.

Microseism is still preventing locking.

We made it up to TRANSITION_FROM_ETMX and then again back past DRMI 2x since the morning but we still lose lock due to instability. Thankfully, it seems that the microseism has reached its peak and is coming around.

Alignment is great and flashes are good and have been tuned (a few times). OPS OBS mode has been changed to MICROSEISM (and SEI_CONFIG is automatically in useism as it has been all day).

Jennie W, Sheila,

I took a long time to post this as have been working on other things...

We carried out a test (see LHO alog #86785) to look at the effect of DARM offset stepping on the power at OMC-DCPD_SUMS and OMC-REFL (transmitted through and reflected from the OMC). We did this with the heater on OM2 off as is nominal.

We then meant to redo these measurements once we heated up OM2 to change the mode-matching of the IFO to the OMC.

Unbfortunately we lost lock at about 15:06 UTC while Corey was taking out first measurement before heating up the OM2.

The meausrement is shown in this image, I have mislabelled it as 'third measurement' but it was the first. The optical gain is shown just before this measurment to be 0.994.

Then we waited as long as we could under out initial parameters of being finished cooling the OM2 again by 1:45pm.

We took another measurement at 1 hr 25 mins into lock after two false starts where I forgot to turn off the ASC. The optical gain was measured right before we started the measurements to be 0.978 but was still thermalising.

And then we took a third 2 hrs 59 minutes into lock, the IFO should be thermalised but the temperature of OM2 was still trending upwards a bit. Optical gain was 0.986.

We can use the slope of the power at the antisymmetric port (P_AS) vs. the power at the DCPDs (P_DCPD) as the DARM offset changes to estimate the throughput of carrier through the OMC which allows us one estimate of the loss.

The plots of this throughput are here for the cold state (minus the points taken after we lost lock), here for the partially thermalised state, and here for the thermalised state.

I am also in the middle of using the plot of P_AS varying with power at the OMC reflected port (P_REFL) to get a better estimate of the mode-mis match between the interferometer and the OMC.