FAMIS 63910

Last Tuesday's interlock work and brief time in the enclosure are clearly seen on many trends, and essentially everything came back as expected. One item of note is the PMC, which relocked at a slightly higher temperature, which seems to have caused the transmitted power to be a bit lower while the reflected power is a bit higher.

[Keita, Elenna]

Sheila and I struggled to lock SRY last Friday, 91360. Keita and I revisited today.

To start, I ran the usual SR2 alignment, which centers the beam on AS_C, and the AS centering which centers OM1,2 on AS A and B.

Then, we could see a large beam at the center of the AS AIR camera, and a strange fringing beam at the top edge of the camera. We swept SRM in both pitch and yaw to both edges and saw the beam disappear. This convinced us that we were seeing the two beams we needed to overlap in SRY, however, there was not an SRM alignment that could overlap the two beams.

Keita first moved ITMY 10 urad in pitch, and was able to overlap the two beams. He then undid that alignment and moved the beamsplitter instead. We were able to achieve the SRY fringing and then lock SRY with the guardian. The resulting beam ended up on the top edge of th AS AIR camera view.

Using that beamsplitter alignment, we then relocked MICH dark, which required a large movement of ITMX, since we had decided to maintain the beamsplitter and ITMY alignment. ITMX is now at P: -135 and Y: 113.1 on the sliders. This means it has been moved relative to where it should be according to a previous arm alignment we achieved.

We can still see the MICH fringes on the ISCT1 refl camera with this alignment.

We can also lock PRX, with a movement of PRM. We still see no beam on POP A or B, so Keita is scanning the input alignment.

The attached screenshot shows the alignment sliders after we locked SRY, MICH, and PRX.

I'm not sure if we are happy with this alignment overall, since we're not sure if this is where we want the ITMs.

Per WP 13472  updated h1daqfw0 to use the new auto-reconfiguring frame writer.  This is the same code has been running on h1daqfw2 for months in a test mode.

I also did an inplace upgrade of h1daqfw0 to Debian 12, which is what h1daqfw2 is running and what we have tested as.

Erik helped with package wrangling for Debian 12.  I had been running h1daqfw2 from the experimental repository (which is a snapshot of the continous integration system).  We were able to move this from using the experimental repository to the unstable repository.  We will move it up to production later.  We don't have a full Debian 12 release of advligorts as we are not planning on supporting the rcg and real time code on Debian 12.

Dave and I will be watching the timings and checksums to make sure everything looks good.  The IO setup is a bit different between h1daqfw2 and h1daqfw0 (fw2 writes to local disk, fw0 to a NAS).

TITLE: 08/03 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 11mph Gusts, 7mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.07 μm/s 
QUICK SUMMARY:
The well pump was not working today due to some electrical issue. Last I heard FAC had a contractor on site to check on the well. So there is limited amounts of water here. Many folks were asked to work from home if they can. 

GRB-Short E644098 @ 17:29 UTC

Jonathan started working on the FrameWrite0 today, installing Deb12 OS. 

End stations were misaligned today to some tests that Camilla was doing.

ITMX ISI Stage 1 & 2 WD tripped twice today. Jim went out to the CER today to fix this.

Vac Team did some work on the GV6 Gate Valve today and GV6 is currently Open on the Y arm, But GV5 is still closed so the corner volume is still not open to the Arms yet. 

Keita and I took an opportunity while JAC was offline to run all the dark offsets. I ran the usual dark_offsets_exe.py from userapps isc/h1/scripts/dark_offsets

I did not visually check all of them but the ones I compared before and after in SDF looked reasonable.

Some of the whitening gain settings have been set strangely for the vent, so this should help fix that now that we have reset the proper settings.

SDFed, see screenshots.

After we ran, Keita and I realized the whitening settings for POP B were still wrong, so I corrected them and reran the offset for the POP B segments. Added screenshot.

Sheila, Ryan S, Camilla

We spent the morning repeating 90783, now that ZM4 preloading has been adjusted (90951) and ZM5 has been swapped and now has a different preloading than our O4 ZM5 (91292):

• Using SQZ ASC with ZM4 and ZM5 to get ASC_A and ASC_B centered, we needed to move SRM to stop saturating ZM4/5,
• then locking OMC on 00 touching up OMC and OM3 alignment to maximize 00 peak,
• then putting these ASC-OMC offsets into H1:OMC-ASC_QPD_A/B_PIT/YAW_OFFSET so that the OMC ASC will put us in this good location. 

Sheila then used her script to run OMC scans at a grid (below) of PSAMS locations. These initially look great, showing sqz to omc mode mismatch is as good as 1%. with some alignment fluctuations. Ndscope of data taking attached. 

Ryan then took M^2 measurements on SQZT7 of a slightly different grid:

Following a similar process for the length control as in 91028, I used both the BSFM and BBSS model to construct a model of the MICH ASC and check the crossover frequencies.

The most recent ASC OLG measurements of MICH P and Y are in userapps asc/h1/templates/MICH. MICH P UGF is roughly 2 Hz, MICH Y is roughly 0.7 Hz. Using the BSFM model and this information, I once again assumed the optical gain of the MICH ASC would be the same and calculated a rad/ct calibration factor to use with the BBSS model. Note that these UGFs are from full power lock, so I'm not certain what the MICH ASC OLGs look like in DRMI lock.

The BSFM model also says that both P and Y have a 22 mHz crossover between M1 and M2.

Using these calibration factors show that we might have some trouble running with the exact same MICH ASC design with BBSS. I think this is because the MICH ASC design contains a pretty extreme BSFM plant inversion. We could replace it with a BBSS inversion, or use this opportunity to move to a slightly different design principle that doesn't require precise plant inversion.

The model also suggests that the yaw crossover from M1 to M2 will be about 22 mHz as before, but shows the pitch crossover would now be 8.5 mHz. I need to confirm I am using the correct lever arms for the calibration to make sure I haven't made a mistake there. Either way, we can confirm the crossover with an injection.

Just as with length, we would need to slightly adjust the locking filter design if we want to move to M1 and M3 actuation, but in principle I don't see any issue with driving from M3 instead of M2 for ASC as well. This would be in line with how we drive all other triple sus for ASC.

First attachment shows the MICH ASC in the BSFM model, second in the BBSS model.

Post upgrade the CDS Overview was showing an issue with h1iopomc0's timing card. On further investigation we found that this timing card is a very early rollout of the V5 firmware, upgraded back in Feb 2025 for DT-frequency changes. The actual issue is that RCG5.65 is more accurately calculating the duotone crossing for h1omc0's low-noise ADCs. This value was +0.1uS pre-upgrade and now is -5.625uS with only nano-second variation. The CDS overview was using the DT crossing time as an indicator of timing card firmware version. V3 had DTs between +7uS and +8uS, V5's are in the -1uS to +1uS range.

I've changed the CDS Overview to extend the lower limit of acceptible DT timings to -6uS. No further action is required.

Rachel and Elenna: 

The goal of this project is to better understand the DARM loop design that was used during O4b and evaluate how well it performed. By identifying where the design worked well and where we observe limitations, we can gain insight into potential improvements for future DARM loop designs.

To do this, I recreated the pydarm.plot.critique() function using valid O4b calibration reports (H1: 20250111T193645Z and L1: 20250102T163026Z). I then broke the DARM loop down into its individual components to understand how each stage contributes to the overall control performance.

The analysis includes comparisons of the open-loop gain (OLG, (G)), the suppression function (1/(1+G)), the digital_out_to_displacement actuation transfer functions, the lock_in_to_displacement actuation transfer functions, annotated crossover frequencies, and the frequency ranges over which each actuation stage dominates. 

Several notable differences emerge between the H1 and L1 DARM loops. H1 has a lower unity gain frequency (72.2 Hz vs. 86.0 Hz), a lower low-frequency OLG magnitude, and substantially less phase margin (22.5º vs. 34.3º). The reduced phase margin is also reflected in the larger gain peaking observed in the suppression function. Regardless of how future DARM loops are offloaded, increasing the available phase margin should be a primary design objective.

The actuator comparisons show that the overall stage hierarchy is similar between the detectors, with the UIM dominating at low frequencies before the TST becomes dominant above approximately 17 Hz. However, the lock_in_to_displacement transfer functions reveal more complicated interactions between the UIM, PUM, and TST at low frequencies than are apparent from the digital_out_to_displacement transfer functions alone.

See: LIGO-G2601606 for slides.

TITLE: 08/03 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 4mph Gusts, 2mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.09 μm/s 
QUICK SUMMARY:

IFO status: Currently Unlocked. Both GV5 and GV7 are shut..... for now.
Corner pump down continues.
Spool cameras work to reinstall IR cameras.
More Distributed acoustic  sensing DAS system.

Following yesterday's swap of h1sush12's IPC fiber and switch-SFP (port3) 23 hours ago there have been no IPC errors from this frontend. Also the 25GE switch (sw-msr-ipc0 port3) shows zero packet errors.

Keita turned on the JAC heater this afternoon.  Attached plot has the first cursor at the time of 91296, the second cursor at the time when Keita turned on the heater, they both happened at the same point in the diurnal pattern where the termperature rises.  

Keita has now turned the heater off before people leave for the weekend, because we can't say it's not causing the pressure to rise.  Let's repeat this earlier in the day on Monday.  

TITLE: 07/31 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
SHIFT SUMMARY: The final bits of the CDS upgrade continued today, as well as some SQZ and michelson commissioning. The LVEA is currently in Operations SAFE. 

The corner station continues to be pumped down, pressures are around 4e-7torr. The HAM1 pressure has been a concern when using the JAC heater this week, but I think we may have been scaring ourselves. The HAM1 pressure changes diurnally regardless of whether the heater is on or off. We have seen a pressure response from turning on the heater, but this diurnal effect might be the dominating factor. Looking at LVEA temps around HAM1 it tracks well with the local temperature. 

LOG:

Sheila, Rahul

We got back into HAM7 for beam alignment work after ZM5 was repaired and, up & running. Listed below are the things we did to check and improve the alignment in HAM7 chamber and also on the SQZT7 irises. 

1. Checked the incoming beam on ZM5 from ZM4, found it to be off in yaw by few mm - hence we translated ZM5 (pushing it in the direction towards SQZT7 table) to center the beam on the PSAMS. 

2. Checked the reflected beam from ZM5 on the iris (which Camilla had set last week) - it was off in Yaw and was too high as well. Hence, I mechanically adjusted the pitch and yawed the suspension cage to center the beam on the iris. Sheila then checked the beam on the two irises in SQZT7. Using sliders we were able to center it nicely on the two irises, however several times while doing so we were eating up on DAC output. Hence iteratively we were using sliders and mechanically offloading Pitch/Yaw by adjusting the pitch adjuster or yawing the suspension cage.

3. Sheila also used ZM4 sliders to fine tune the alignment on the irises on the table.

Current status - we have centered the beam on the two irises in SQZT7 but we might have to mechanically offload ZM5 or perhaps ZM4 as well. ZM5 has all four dog clamps attached and baffle installed as well. 

We removed the yellow viewport cover (and guillotine) from HAM5, removed the foil and opened the gate valve on HAM7 viewport (going towards HAM5) and then confirmed that the beam is injected  into HAM5.

Sheila, is fine tuning the IFO alignment before aligning the two beams (IFO and squeezer) in HAM6 photodiode.

We also did some power measurements in HAM7 chamber, mainly on the OPO and then compared it against SQZT7 table. Sheila will posting the numbers later on.

WP13479 Move last ADC in h1susb2h34 in front of the LIGO-DACs

Erik, Jonathan, EJ, TJ, Dave:

The 3rd ADC, which was after the LIGO-DACs on the PCI bus, was moved to be before the LIGO-DACs. EJ found that if a General Standards card followed the LIGO DACs, and there are other General Standard DACs in the chassis, then the DAC mapping became ambiguous. This was first discovered by TJ when he noticed that the LIGO-DAC card temperatures was being reported as -1C (not being read). We then found that model's LIGO-DAC drive counts were being reported by h1iopsusb2h34 on the wrong DAC MEDM.

A quick fix as to move the ADC inside the IO Chassis from after to before the LIGO-DACs

The original card layout (BIO not shown):

The new card layout (BIO not shown):

I was able to shuffle the cards without disconnecting any rear cables except ADC2 (SUS_HAM_209) and the MTP. The cables had enough slack to pull the chassis out to access the card screws. At the rear I was able to push the h1susauxb2h34 chassis forward to access the interface cards.

Internally only ADC2's ribbon cable needed to be disconnected.

TJ methodically started driving the top stages for MC2, PR2 and BS. We verified the model's and IOP's MEDM reported the correct channels being driven.

I trended the ADC2 channels from before and after its move to verify it is connected correctly.

Travis, Gerardo, Jordan

During the closing of GV6 back in May, we noticed that there was some blow-by in the pneumatic system when trying to hard close the valve, see alog 90093. 

We were able to hard close the valve eventually but as preventative maintenance we wanted to replace the air cylinder seals, similar to GV7.

Prior to disassembly we measured the locations of the reed switches from the top surface of the bottom plate to the bottom surface of the reed switches:

Bottom Switch: 1 1/8"

Top Switch: 49 1/4"

We then disassembled the air cylinder and replaced the seals following procedure/notes collected during the GV7 repair. During cleaning of the old grease on the piston head, we noticed there were two burrs on the top of the piston, we did not notice any damage to the inside of the cylinder, but as a precaution we used a small flat file to remove the burrs. We also chased the threads on the four threaded rods with a die to aid with reinstallation. After cleaning and inspection of the cylinder tube, we found no issues or damage so we decided to continue to use that cylinder and keep the new one as a spare.

No other issues encountered, we removed the old seals, cleaned the grooves, added copious amounts of the supplied grease to the o-rings, seals and the inside of the air cylinder, and then re-assembled the cylinder tube. Pictures posted below and a final procedure is in progress and will be posted to the DCC.

We did not get a chance to cycle the valve after the seal replacement, so we will continue tomorrow with cycling the valve.