H1 just had a drop from OBSERVING due to the Squeezer's OPO_LR.  The Squeezer came back on its own in less than 2-min.

We do have the following message for the SQZ_OPO_LR node: 

"pump fiber rej power in ham7 high, nominal 35e-3, align fiber pol on sqzt0"

And it looks like SHG Fiber Rejected Power has had a high value (over 0.350 counts) since Mon (see RyanC's alog83406) and has been railing at 0.753 the last few days. (see attached).   Trending back further shows that this Rejected Power hasn't had this sustained railing since way back in Aug-Oct 2023.

Since H1's been (1) running like this the last few days, (2) SQZ came back quick, and the (3) H1 range looks "normal (around 150Mpc)----took H1 back to Observing and tagging SQZ.

Mayank, Jennie, Siva, Keita

Continuing measurements carried out on the ISS arrray in alog 83077 (between that alog and today Siva and Mayank had set up measurements of the first four ISS array PDs with oscilloscopes).

One problem emerging was that the QPD (shown in this image) readout doers not give a number for how far from centre the QPD is in our lab setup (it uses an old LCD output box with a microcontroller we can't find the documentation for). Another is that the four PDs are best aligned away from the centre of the QPD. So after testing it may be neccessary to move the QPD for best alignment.

This morning Siva and Mayank setup the readout for all 8 PDs and also added a polarising beamsplitter between the PZT controlled mirror used for dithering the alignment to the array, and the aperture on the array assembly input. This was to ensure the polarisation was not affecting the measurement.

Mayank and I measured the AC and DC signals for all 8 PDs using a horizontal dither on the PZT controlled mirror before the polarising beamsplitter, when:

1: the light was centered on the QPD and

2: when it was in the observed 'best alignment' when the coupling from the dither to the PDs was mininimised.

Changing the DC alignment is done with the pitch and yaw screws on the PZT mirror mount.

After the first couple of measurements we tried to get a time when the laser was not in a noisy state this could be because it keeps running multi-mode or some pickup in the measurement cables - not sure so further investigation needed.

It does seem possible to obtain a spot where all the 8 PDs are minimised in the top left-hand quadrant of the QPD for.

We also repeated measurements 1 and 2 with a vertical dither on the PZT. This is the LCD screen when aligned at its best alignment on the PDs for vertical dither on the PZT mirror. This is the readout for PDs 1-4 and 5-8 at this position. This is the LCD screen when the input alignment is such that the QPD is centred.

I have attached our data file references for the measurements and some photos.

Keita also tuned the laser temperature control thermistor from a resistance of 10 kOhms to 9.602 kOhms which seems to stop the laser mode-hopping and becoming noisy. Siva has also hooked up a cable between the QPD and a different QPD readout box which we can get oscilloscope readouts from. More measurements to follow...

For FAMIS #26368:  All looks well for the last week for all site HVAC fans (see attached trends).

TITLE: 03/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 146Mpc
INCOMING OPERATOR: Corey
SHIFT SUMMARY: Several hours of downtime today thanks to some earthquakes this morning and high winds this afternoon. Eventually we were able to relock, and so far H1 has been observing for about 1.5 hours. Quiet day otherwise.
LOG:

• 15:00 - Lockloss from EQs - alog83481
• 17:40 - Seismic back to CALM, starting lock acquisition
• 18:19 - No luck due to high winds, waiting some more
• 19:21 - Winds have calmed slightly, trying again
• 20:45 - Was able to get past DRMI a couple times after touching PRM, but locklosses at CARM_OFFSET_REDUCTION tell me more adjustment is needed, so starting initial alignment
• 21:04 - Alignment finished, starting lock acquisition
• 21:49 - Reached NLN fully auto
• 21:53 - Observing

TITLE: 03/21 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 12mph Gusts, 7mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.33 μm/s
QUICK SUMMARY:

H1's been Observing for 90min and so far the environment looks decent for evening operations (winds mostly under 10mph); it's been raining the last few hours.  Ryan passed on how locking went for him and there is an opportunistic Observing-Drop for Robert---if L1 is out of Observing.

H1 returned to observing at 21:53 UTC after several hours of downtime due to earthquakes and high winds. The wind has calmed down enough that I was able to relock after an initial alignment.

I accepted the SDF diffs Sheila predicted in alog83483 before going to observing, screenshot attached.

Bi-Weekly TCS Chiller Water Level Top-Off Famis 27811

CO2X

• Before: 29.5
• After: 30.2
• + 250 ml

CO2Y

• Before: 9.9
• After: 10.5
• +175 ml

There was no water in the leak cup.

Fri Mar 21 10:05:37 2025 INFO: Fill completed in 5min 34secs

HEPI Pump Trends Monthly. Last Checked in alog 82928. Closes FAMIS 37203.

Trends look as expected and are comprable in noise to last month.

Since I changed the ramp time to 2 seconds for the second time, there hasn't been a change in the rate of these locklosses, there have been 8 per nln lockloss since March 18th at 21 UTC.  I've now changed the ramp time back just to avoid an unnecessary change to ALS.

Oli used data from the lockloss tool to make this useful plot showing how many locklosses we've had from the LOCKING_ALS state (state 15 for ISC_LOCK), blue shows the total number of state 15 locklosses for that day and orange shows those that were tagged as high wind or EQ.  This shows the problem starting on the 22nd or 23rd UTC time, which might line up in time with this change to the ALS demod phase and locking gain: https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=82388

Because of the large EQ right now, we can't lock the Y arm to measure the TF.  I've reverted the changes, and accepted the changes in SDF safe.snap.  They will need to be accepted in observe.  It would also be a good idea to measure the OLG when we can.

FAMIS 26376, last checked in alog83399

Laser Status:
    NPRO output power is 1.834W
    AMP1 output power is 70.15W
    AMP2 output power is 140.0W
    NPRO watchdog is GREEN
    AMP1 watchdog is GREEN
    AMP2 watchdog is GREEN
    PDWD watchdog is GREEN

PMC:
    It has been locked 44 days, 19 hr 39 minutes
    Reflected power = 22.58W
    Transmitted power = 106.0W
    PowerSum = 128.5W

FSS:
    It has been locked for 0 days 0 hr and 12 min
    TPD[V] = 0.7967V

ISS:
    The diffracted power is around 3.9%
    Last saturation event was 0 days 0 hours and 55 minutes ago

Possible Issues: None reported

Lockloss @ 15:00 UTC - link to lockloss tool

S-waves from two M6.2 earthquakes, one from Panama and another from the Aleutians, AK hit at pretty much the same time, sending H1 into EQ mode and losing lock. Since the R-waves are still 15 minutes out from the Panama quake and there have already been some aftershocks, I'm leaving H1 in DOWN until those pass by.

TITLE: 03/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 141Mpc
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 23mph Gusts, 18mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.34 μm/s
QUICK SUMMARY: H1 has been locked and observing for almost an hour; two locklosses overnight. Ibrahim notes he was called this morning and I've cleared the H1_MANAGER alert.

• Wind up and down overnight, currently gusts up to around 30mph
• All other systems nominal, no alarms

IFO is in NLN and OBSERVING as of 13:43 UTC <5 minutes after getting the OWL call. I did not touch anything.

Was called at 6:37AM. Logged on to check what the problem was but it seemed that we just hit the 2 hour post-lock OWL call threshold, seemingly due to high winds preventing lock/causing lock acquisition lock losses.

By 6:41AM, we were locked and OBSERVING by 6:43 AM.

I am having issues clearing the OWL due to a NoMachine Malfunction. Will leave it to DAY OPS in 30 mins.

(Gerardo, Janos, Rogers Machinery Techs (Samuel Ragsdale and Brandon Pimentel))

Late entry.

On Tuesday, we had a couple of service technicians from Rogers Machinery complete the annual maintenance for the Kobelco compressor, no hiccups were encountered during the maintenance job.
A couple of notes regarding the service:

1. water hoses and tubing will need to be replaced probably by the next service.
2. the aftercooler o-ring sealing surface is showing wear, and it will need inspection during the next service.  

The compressor will be ready to use once we test and get an acceptable dew point.

(Jordan, Gerardo, Janos)

Late entry.

Last Tuesday 3 ion pumps were incorporated to the filter cavity tube.  The ion pumps were installed some time ago, and they remained valved out until last Tuesday.
The ion pumps are located on the filter cavity tube crosses B4, B5 (installed here) and C1 (installed here).
New MEDM screens were created for the signal for each pump (see first attachment), each respective signal is obtained from each of the ion pump controllers, for these ion pump we are using the LPC GAMMA type controllers.  For the pressure effect see second attachment.

To incorporate the ion pumps, FC-B-4 and FC-B-5 to the rest of the filter cavity 3 valves were closed, FCV-3, FCV-4 and FCV-5.  Then to incorporate ion pump FC-C-1, valve FCV-6 was closed.  After the performance of the ion pumps was confirmed all the gate valves were opened.

TITLE: 03/21 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: Relocking was automated and quick when the wind died down. We've been locked for ~ 4 hours.
LOG:                                                                                                              

01:11 UTC Observing

At the EY station the compressor is being replaced - after the one at EX is done. In this aLog, in the comments, the progress of this operation is tracked continuously, until the 1st startup by the supplier, Rogers Machinery.
Another important consideration here, is that the purge line at EY needs to be replaced (based on an FTIR test - see DCC LIGO-E2300222-v2. As it can be seen, the level of contamination reaches even the 10 ug/cm2 value). This operation will be done after the April-May vent, so the EY station will be ready to be vented after O4.

02-25 (maintenance Tuesday): the old compressor was pulled out (it is temporarily stored in the EY receiving area). The beginning of the purge and TMDS lines with the associated brackets and unistruts were taken off. The new compressor unit and dryer skid were anchored in the mechanical room. Here it is important to mention that the orientation of the inlet was brought closer to the purge line inlet into the VEA, so the overall length of the associated circulation lines will be much shorter.
Next is the electrical and pneumatic installation, which will be completed in the next 1-2 weeks.

Jennie W, Sheila

Summary: We altered the offsets on the H1:ASC_OMC_{A,B}_{PIT,YAW} QPDs which are used to align the beam into the OMC. This was aiming to give us a improvement in optical gain. After doing this we aimed to measure the anti-symmetric port light changing as we chnage the darm offset. We are trying to use both these measurements to narrow down where we have optical loss in that could be limiting our observed squeezing. Performed both measurments successfully but the different alignment of the OMC made the squeezing less good so Camilla (alog #83009) needed to do some tuning.

Last time (alog #82938) I did this I used the wrong values as our analysis used the output channels to the loops instead of the input channels which come before the offsets are put in. The new analysis of our measurement of the optical gain as seen by the 410Hz PCAL line, changing with QPD offset, shows that we want the loop inputs to change to:

H1:ASC_OMC_A_PIT_INMON to 0.3 -> so we should change H1:ASC_OMC_A_PIT_OFFSET to -0.3

H1:ASC_OMC_A_YAW_INMON to -0.15 -> so we should change H1:ASC_OMC_A_YAW_OFFSET to 0.15

H1:ASC_OMC_B_PIT_INMON to 0.1 -> so we should change H1:ASC_OMC_B_PIT_OFFSET to -0.1

H1:ASC_OMC_B_YAW_INMON to 0.025 - so we should change H1:ASC_OMC_B_YAW_OFFSET to -0.025

We stepped these up in steps of around 0.01 to 0.02 while monitoring the saturations on OMC and OM3 suspensions and the optical gain, both to make sure we were going in the correct direction and that we were not near to saturation of the suspensions as hapenened last time I tried to do this.

Attached is the code and the ndscope showing the steps on each offset, (top row left plot, top row center right plot, second row left plot, second row center right plot). The top stage osems for OM3 suspension are shown in the third row left plot, the top stage osems for OMC suspension are in the third row center left plot, and the optical gain is shown in the third row right plot.

The optical gain improved from by 0.0113731 from a starting value of 1.00595, so that is an improvement of 1.13 % in optical gain.

Around 19:04:28 UTC I started the DARM offset step to see if the change in optical gain matches that we would see if we measured the throughput of HAM 6. Unfortuntely I forgot to turn off the OMC ASC which we know affects this measurement of the loss. We stood down from changing the OMC and Camilla did some squeezer measurements, then I made the same mistake again the next time I tried to run it (d'oh). Both times I control-C'd the auto_darm_offset.py form the command line which means the starting PCAL line values, and DARM offset had to be reset manually before I ran the script successfully after turning the OMC ASC gain to 0 to turn it off.

The darm offset measurement started at 19:20:31 UTC. The code to run it is /ligo/gitcommon/darm_offset_step/auto_darm_offset_step.py

The results are saved in /ligo/gitcommon/darm_offset_step/data and /ligo/gitcommon/darm_offset_step/figures/plot_darm_optical_gain_vs_dcpd_sum.

From the final plot in the attached pdf, the transmission of the fundamental mode light between ASC_AS_C (anti-symmetric port) DCPD is (1/1.139)*100 = 87.8 %. We can compare this to the previous measurement from last week with the old QPD offsets to see if the optical loss change matches what we would expect from such a change in optical gain.