All h1omc0 models (h1iopomc0, h1omc, h1omcpi) were restarted with version 5.3.1 of the RCG.  This version changes the ramp function when turning on and off ramp-switched filters from a linear ramp to the so-called quadratic ramp. 

A linear ramp has the formula r = q  where q = (t - t0)/(t1 - t0), the new ramp has the formula r = -q⁴ + 2q², which has the nice property that dr/dq = 0 when q = 0 or q = 1.

This change is an attempt to address the problem described here: 81638

J. Kissel, T. Sanchez, L. Dartez

As we began to use the new OMC DCPD test infrastructure (LHO:78956, LHO:78975) to pick up where we left off in characterizing the new-to-O4, segregated OMC DCPD, 524 kHz low-noise ADC system (LHO:78516, LHO:78559), we found in necessary and fruitful to
 
- shift some of the installed filters around in the A2 and B2 banks (the one's the replicate the reverse-calibration filters that turn the raw ADC counts in mA on the DCPDs; the copies of the A0 and B0 "NewV2A" and "NewAW" -- moved from FM1 and FM2 to FM2 and FM3 like they are in the A1 and B1 banks.)

- add the 1 Hz 5th order elliptic high-pass as an option to the A2 and B2 filters in FM1 (like the A1 and B1 banks) and 

- split out "divide-by-four" gain of 1/4 that turns the sum of the four channels into an average from the "cts2V" ADC calibrating gain of 40 / 2^18 [V/ct] = 0.00015258789 [V/ct] ~ 0.0001526. The ADC gain in th previous cts2V bank was actually implemented as a typo of the 16 bit ADC calibration divided by 4. The ADC gain should be 40 / 2^16 [V/ct] = 0.00061035156 [V/ct], but was installed as 0.0006105 "[V/ct]." And then the multiplication of the gain of 1/2^2 = 1/4 = gain(0.25) to convert from 16-bit to 18-bit calibration was immediately adjacent to the gain(0.25) for turning the sum into an average. Not so clear.

So, what was 
    cts2V = gain(0.0006105)*gain(0.25)*gain(0.25)
in FM4, is now two separate filter banks
    18b_cts2V = gain(0.0001526)
    sum2avg = gain(0.25)
in FM4 and FM5.

The new filter banks and arrangement have been committed to the SVN under 
    /opt/rtcds/userapps/release/cds/h1/filterfiles/
        H1IOPOMC0.txt       rev 30385

Also -- it appears as though the B1 and B2 filter banks didn't have their filters properly *un*monitored when I touched the SDF system last week (LHO:82155). The configuration changes (made during Monday commissioning time) thus had prevented returning to observing. I've rectified that as well, so now, *really* these A1, A2, B1, and B2 banks' EPICs records can be changed at will during observing.

TITLE: 01/14 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 4mph Gusts, 3mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.45 μm/s
QUICK SUMMARY:

PEM and SUS charge measurements currently being taken. We've been Locked for over 5.5 hours. Today is an 8 hour maintenance day.

Workstations were updated and rebooted.  This was an OS packages update.  Conda packages were not updated.

TITLE: 01/14 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 162Mpc
INCOMING OPERATOR: TJ
SHIFT SUMMARY:

IFO is in NLN and OBSERVING as of 04:47 UTC

Smooth shift with one Lockloss caused by the ETMX glitch (alog 82254)

Per Ryan C's instruction from Ryan S, I also adjusted the PSL ISS Ref signal (attached pic) to bring the refracted power above 4.

There was one SDF Diff that I accepted (also attached).

LOG:

None

Lockloss likely caused by the ETMX glitch. EX L2 OUT channel shows erratic movement 170ms pre-lockloss (attached screenshot)

Bright beam spot on HAM3 ballast mass baffle moves with ITMY compensation plate yaw motion

We have been looking for the source of the scattering noise that varies  with the ITMY compensation plate yaw setting (80499). I recently searched for beam spots in the HAM3 area that move as CPY is yawed, using movies that I took from both the MC2 camera viewport and the PR2 camera viewport near HAM2.  Anamaria and I had done some of this before (77631) but this time I recorded the CP movements on the audio track of the movies for a more precise correlation. And I also modified the movies in iMovie to increase visibility of faint spots. Figure 1 shows that I did find a spot that moved precisely with CPY Yaw settings (link to movie clips: https://youtu.be/FDdNDPoQadU ). The spot appears to be on a ballast mass baffle (see Fig. 1), which is not angled as much as the scraper baffle (which I think the beam is supposed to fall on (Alena's slides)) and may thus retroreflect more light.

Mystery  beam spot on HAM3 spool piece comes from ITMX direction, not HAM2 direction

I had previously misinterpreted the pattern of light on edges and bellows of the HAM3 spool piece as suggesting that the mystery beam spot (78192) was coming from the HAM2 direction . More recently I found that there was light on the HAM3 side of the MC baffle that had a similar interference pattern and was consistent with being part of the mystery beam spot (Figure 1). The light on the HAM3 side of the baffle was visible when looking through the viewport for the PRM camera at a high angle. Thus, the beam is most likely coming from the ITMX direction, travelling close to the –Y wall of the beam tube.

One possibility is that it actually comes from ITMX, either scattered light from ITMX or scattered light from the back side of MC2 reflecting off of ITMX. Figure 3 shows these suggested paths and a picture taken from the point of view of the beamspot on ITMX that shows that there is a clear path to the site of the mystery beam spot. I think that the cartoon shows that it would be worth using a real model to determine if these paths are possible.

I checked to see if the beamspot on the eye baffle moved or modulated when I actuated the compensation plates. I made movies as I moved the two compensation plates more than 600 microradions in pitch and yaw, but, unlike the spot on the ballast mass baffle, I did not see any modulation or motion of the spot on the eye baffle.

TITLE: 01/13 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 160Mpc
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: The bottom monitor of NUC31 looks pretty dim today, we've also had a standdown query failure on OPS_OVERVIEW. The failure is from the last query being greater than 4 minutes from the current time, the last query was 01/11/25 15:25 UTC. We've been locked for 6 hours, range coherence check yielded.
LOG:                                                                                                                                                                                                                                             

• 16:48 UTC I adjusted the OPO temp while relocking.
• 17:03 UTC TRANSITION_FROM_ETMX lockloss
• 18:29 UTC NLN and start of Commissioning
• 19:37 UTC SEI to CALM
• 19:44 UTC Observing after wrangling some SDFs

TITLE: 01/14 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 162Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 6mph Gusts, 4mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.52 μm/s
QUICK SUMMARY:

IFO is in NLN as of 19:20 UTC (5hr 30 min lock)

Sheila, Jennie W

During commissioning window today we measured the P2L and Y2L gains for the PR2 mirror.

This is part of the work to understand how to move the beam on PR2 in order top avoid a reflection and subsquent stray beam off the PR2 scraper baffle (as found in alog #77631 by Annamaria and Robert).

The P2L gain was close to optimised and has been left at -0.36.

The commissioning window ran out before I could finish optimising the Y2L, I have left it at -7.00 which gave better A2L decpupling than the previous value.

Method:

• Inject line on PR2 M3 stage pitch at 30Hz using the OSC 9 filter bank in the ADS.
  • sitemap-> ASC -> Dither overview
• Check the PIT9 filter bank at the bottom of the page is not being used (CLK gain = 0).
• Set the matrix at the right of the row to have a 1 in the PIT9 to PR2 cell.
• Check there is a ramp time in the PIT 9 filter bank.
• Set the frequency to 30 and step the amnplitude to 1 in a couple of steps.
• Measure a reference for DARM and PRCL. The red and blue traces show the case when injecting into pitch with nominal A2L gains.
• Set the aevraging to exponential and zoom in on the line.
• Change gain in HzTS->PR2-> M3 DRIVEALIGN->P2L

 Do this until the line height relative to the background is minimised, allowing time for the ramp and a couple averages each step. One thing to note is that the line height above the background in the PRCL spectrum (LSC-PRCL_OUT_DQ) is much less than the relative height above the background in DARM which suggests that the noise in PRCL is not coupling strongly to DARM.

Switch off the line and set the PIT 9 amplitude to 0 counts.

Then repeat the above for the YAW 9 oscillator channel in the ADS, changing the gain in the Y2L gain filter bank in order to minimise the line height. The reference values for yaw are in the photo linked above with the green line showing DARM (we had gone into NLN cal meas with SRCL FF switched off for Elenna's SRCL tests so that is why DARM shows elevated noise). The orange line is the reference value of PRCL using the nominal Y2L gain. The same amplitude was used in the oscillator for this line but it was much higher above the PRCL background noise than for the pitch degree of freedom.

Template is at /ligo/hom,e/jennifer.wright/git/2025/A2L/20250113_A2L_PR2.xml

Since the last report siding, insulation, roofing and doors have all been installed. In addition, a concrete transition between the asphalt and slab was poured as well as a walkway & equipment pad to/near the mandoor. With that, the building construction is complete. Keys were handed over last Thursday 1/9. I have began the process of populating the space with site equipment. Richard and I are making preparations to get basic electrical items ran to the building. 

T. Guidry

There are not yet any results to report about the SRCL dither arm power measurement, but I have some notes about the attempts to run this measurement over the last few commissioning periods.

This measurement works by using the radiation pressure coupling of SRCL to induce differential radiation pressure in the arms, which depends on a couple factors, one being the arm power. This measurement is made by injecting into the SRCL control signal, and measuring the transfer function of of the relative intensity noise on the transmission QPDs of each arm to DARM.

Measurement requirements:

• know the calibration of DARM well (must be CAL DELTA L in this case)
• turn off the SRCL feedforward
• Make sure the TMS QPDs are centered
• ensure high coherence (>0.9) of DARM to TMS QPDs

However, I once caused a lockloss running Craig's measurement templates, so I wanted to be sure that I could drive hard enough to get the required coherence, but not break the lock.

Last week, I ran a couple of test measurements with the SRCL feedforward off, and the TMS QPDs as well centered as possible. I have a screenshot of the results below. You can see that the DARM/SRCL coherence is very good, but the DARM/TMS QPD coherence is very bad. This is true for the NSUM channels as well as the individual segments. When I tried to drive harder, I would get ETMX saturation warnings. The signal appears almost four orders of magnitude above the noise in DARM and about one order of magnitude above the noise in the TMS QPDs.

The centering loops we use center onto QPD B of both arms, but cause the beam to be off center on QPD A in both arms. However, the coherence is equally low on both the A and B QPDs, so I don't think the centering is the issue. Craig and I previously tried centering onto the A QPDs, but then you become miscentered on B, and also cause other problems, see 67066.

Today, I instead drove single lines using awggui. I was able to achieve >0.9 coherence at three different frequencies without causing any saturations anywhere, at about 70 Hz, 49 Hz and 34 Hz. Good coherence was observed with both the NSUM channels and the individual segments of the TMS QPDs. I also confirmed that we see the expected differential phase in the signal between the X and Y arm.

We were not thermalized today, so I plan to rerun this measurement on Thursday using these three points. This should be sufficient information to measure the arm power, and also confirm that we observe the predicted 1/f^2 coupling. I can also use the regularly scheduled Thursday calibration measurements to make sure we know the CAL DELTA L calibration.

19:44 UTC we wrapped up commissioning which started late due (~18:30 UTC) to not being locked. I had to accept/revert some SDFs to get back to observing, ASC, PR2, and OMC.

Mon Jan 13 10:11:32 2025 INFO: Fill completed in 11min 28secs

Jordan confirmed a good fill curbside. TCmins [-86C, -84C] OAT (0C, 32F)

Alerted by H1_MANAGER that it needed intervention. There was a large earthquake coming through that had tripped the ISIs for the ITMs and ETMs. Also, ETMY stages M0 and R0 had tripped (not yet sure if that is just due to the ISI tripping).

There was also a notification on verbals from 08:51UTC, a minute after everything tripped, that says "ETMY hardware watchdog trip imminent", but when I checked the hardware watchdog screen everything looked normal with no countdowns. Once it looked like the worst of the earthquake had passed and the ISI values were all within range, I reset R0 and M0 for ETMY and reset all four ISI watchdogs. We are still in LARGE_EQ mode so we haven't started relocking yet, but it looks like we are close to leaving and we should be good to go for relocking.

Unknown cause lockloss but reasonable to assume it was either microseism or squeeze related (though I'm unsure if SQZ can cause a LL like that).

The lockloss happened as I was adjusting the SQZ OPO temperature since in the last hour, there has been a steady decline in H1:SQZ-CLF_REFL_RF6_ABS_OUTPUT channel. After noticing this, I went out of OBSERVING and into CORRECTIVE MAINTENANCE to fix. It was actually working (the channel signal was getting higher with each tap when the LL happened. This coincided with a 5.2 EQ in Ethiopia, which I do not think was the cause but may have moved things while in this high microseim state. I've attached the trends from SQZ overview and OPO temp including the improvements made. If it is possible to induce a LL changing the OPO temp, then this is likely what happened, though the LL did not happen when the temp was being adjusted, as the 3rd screenshot shows.