Jennie W, Keita K,

While the laser was off and the chamber closed we measured the response function between the JAC PZT driver and the JAC TRANS A PD. We expect some coupling as the two cables are routed together along the table and to the feedthrough.

See the attached plot. The red measurement was at a whitening gain of 10 dB in Beckhoff with the -10dB filter engaged on the JAC TRANS A LF filter bank. The blue measurement is with the whitening gain at its nominal of 30dB, with the -30dB filter engaged in the filter bank instead.

We don't know yet if this level of coupling will affect us until we start locking again at our nominal input power.

Jennie W, Keita K,

Since the doors went on today, Keita and I checked our JAC + IMC model sdfs in prep for model updates to the h1ascimc model tomorrow.

I include a photo of what we accepted/reverted.

Some of these may get changed again during commissioning once we turn up the power.

Still need a similar check of SAFE sdfs for JAC locking but this is less urgent as we don't need any model changes in the near future and are still working on optimising the JAC-REFL locking.

TITLE: 02/27 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM1 -Y door is on! Viewport and +Y door will have to wait

HAM1 - SUS TFs DONE (JM1, PM1)
HAM1 - Septum covers off, final table checks DONE
HAM1 - Install -Y Door DONE
HAM1 - Install -Y Door Viewport NOT DONE
HAM1 beam check thru viewport DONE
HAM1 - Layout pix DONE

LOG:                                                                                                                                                                 

Jordan, Randy, Eric, Tyler

Once we got the go ahead from Betsy, we installed the -Y door on HAM1 (particle counts were 0/0/0 in the cleanroom). Initially no issues, but as we brought the door close to the flange, the inner o-ring jumped out of the groove. We had to move the door back from the flange and re-seat the o-ring. 

With the door tacked with ~8 bolts, we removed the blank on the A2F3 port so they could check beam alignment on the viewport to be installed.

2nd time was the charm, the o-ring stayed in place so we installed and tightened all bolts. The gap closed up evenly. +Y door still to be installed.

Jordan and Camilla pulled the FirstContact from the JAC viewport in prep to install it on the -Y door.  Unfortunately the inner glass surface was still showing many dots of particulate so we decided to re-FirstContact clean it.  I poured on a new sheet and we are now letting it dry overnight.  Install will need to happen tomorrow after we pull the sheet and hopefully have better results.  This seems to be typical of FirstContact these days - needing to reapply a second time on numerous optics...

PM1 is looking good. We've been having more struggles with this suspension the past few days but figured everything out.

The issue was that the OSEMs suddenly started moving much more and were saturating the ADC. We started seeing PM1 constantly saturating when it wasn't being damped starting this week, when the other undamped suspensions in chamber were not saturating. It seems like this started on Sunday Feb 22, 2026, 21:48 UTC (13:48 Pacific). This is when the purge air line was fixed and let back into HAM1, and when a second cover was installed on the +Y chamber door (89225). The other suspensions aren't moving anywhere near as much as PM1, but PM1 is also on the edge of the table so that might have contributed. I took spectra of PM1 and RM1 for two timespans: last week when the purge air was 'normal' and no one was in chamber, and this week when the purge air was at the new 'normal' and no one was in chamber (ndscope). You can really see the difference in how much more the OSEMs are moving for both suspensions these last few days, and comparing the two suspensions you can also see that PM1 is always noisier than RM1 (PM1, RM1). Luckily as long as we are damping PM1 it is looking good.

After we figured that out and replaced an OSEM (89285), I took some closeout transfer functions for PM1. They're looking good and comparing them to May 2025 and to a few days ago before the OSEM swap, they match up well

Settings:
- ISI DAMPED
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-26_1730_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-26_1730_H1SUSPM1_M1_ALL_TFs.pdf
r12925
Comparison:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-26_PM1_May2025vsFeb2026_ALL_TFs.pdf
r12928

I transitioned to laser hazard once the door crew broke for lunch and Camilla and I looked at where the JAC Refl beam comes through.  It is (expectedly) coming out a bit off center (1.5" off in yaw and less than 1" off center in pitch) but with a bit over 5" on the clear aperture of the viewport window we (and Keita and Sheila) are all good on this pointing.  Camilla transitioned back to laser safe and the door crew is going back at it.

JM1 looks good in transfer functions and is ready for doors!

We wanted to verify that our current offsets for JM1 (specifically Y:-840) is not near the edge of our physical range or DAC range.

Initially I had tried taking transfer functions for JM1 with the OPTICALIGN offsets ON, but that limits the amount we can drive so as to not saturate, but that then gives us really bad coherence (and purge air doesn't help). Luckily we can still see the peak locations, and since the frequencies haven't shifted, that means that we aren't close to touching.
I then compared the MASTER_OUTs for JM1 and RM2 (who also has a large OPTICALIGN Y: +935) with the offsets ON. The signal chain for these two are the same so they should be comparable. I found that RM2 has a higher min/max in the MASTER_OUTs, and that value is only half the max DAC range, so JM1 is also fine DAC-range-wise.

After confirming that I turned the OPTICALIGN offsets OFF and took transfer functions. They look good and match the initial set taken in December! 

Settings:
- ISI LOCKED
- DAMP OFF
- OPTICALIGN OFF (too hard to get good coherence without saturating with offsets on)
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM1/SAGM1/Data/2026-02-26_0015_H1SUSJM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM1/SAGM1/Results/2026-02-26_0015_H1SUSJM1_M1_ALL_TFs.pdf
r12924
Comparison:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-26_JM1_Dec2025vsFeb262026_ALL_TFs.pdf
r12927

*The jump in magnitude between these measurements and the previous is due to a factor of 4 that accidentally got removed. See 89198

Yesterday, ground loop checks revealed a new and random ground loop issue on the LR BOSEM of the Tip Tilt PM1 suspension (which has been installed and used in vac for a long while now).  This morning I worked to swap the BOSEM for a new one, reset the medm offset/gains and recentered.  Fil confirmed that the ground loop situation is now resolved on PM1.  In Corey's absence, I took a bunch of photos (won't be as good as his but here for posterity) of the chamber components as we see them before closing up.  I wiped down some of the under table surface as I could.  Jim and I both inspected for left behind items on and under the table.
BOSEM SN 263 is the problem OSEM removed, SN 229 was swapped in with OLV 28860.

Jim then removed the septum viewport covers (all 4)and unlocked the ISI.  Oli ran the final closeout TFs for PM1 (JM1 and JM3 were yesterday).  I revisited the closeout check sheet and we launched the door crew (Jordan, Randy, and FAC - thanks for jumping in due to others absences!).  1 door is on now and we are about to check that the JAC Refl beam goes through the viewport on the door as anticipated given the inaccuracy of the viewport simulator fixture.

Thu Feb 26 10:06:39 2026 INFO: Fill completed in 6min 35secs

TITLE: 02/26 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 6mph Gusts, 3mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.26 μm/s 
QUICK SUMMARY:

HAM1 work is quickly heading towards doors!

The default workstation conda environment was updated.  ndscope is updated to 0.20.7.  A list of changes can be found here: https://git.ligo.org/cds/software/ndscope/-/blob/master/CHANGELOG.md.

tmux and some other system commands were dropped from the conda environment.  tmux should now work in the terminal.

S. Muusse, C. Compton, G. Valente

Alignment of 4.65um beam on the ITMY was completed, excluding the QPD optics which require reflection off the ITM. I've attached a picture of the almost complete table with the notable optics modified today indicated. I'll get someone taller to add a better picture in the comments of the whole table.

• All the PD optics were placed and aligned (another picture).
• The PD electronics (x-arm Chassis & PD power supply) were temporarily installed and slow and monitor channels were shown to be operational.
• Thermal pickoff aligned.
• The beam dump flipper orientation has been problematic but has been solved by dumping when the flipper is vertical and placing the beam dump at a ≈ 30deg angle (picture attached).

Next steps:

• Installing the visible laser and associated optics
• Testing the rotation mount and translation mount
• Testing y-arm chassis

The Medm screen is now in a workable form if not particularly finessed.The screen is called TCS_CHETA.adl and a shortcut was added for the X and Y arms by camilla to the TSC screen.
There is still work to be done here calibrating the powerdetectors and power meters.
note: currently power in for the rotation mount .adl is the laser diode current and should be changed to laser power when calibrated

F. Clara, K. Kawabe, M. Pirello

We checked the following for ground loops:

CER:
Beam Diverter Cables - Both tested good.

From SUS R1:
JM1 is good
JM2 is good
JM3 is good
PM1 - Pin 2 is grounded, Shield is not connected to pin 13 (cable HAM1_311)
RM1 - Shield is not connected to pin 13 (cable HAM1_228)
RM2 is good

From ISC Racks:
ISC_222 (db9) pin 5 not tied to shield, signals good
ISC_221 (db9) pin 5 not tied to shield, signals good
ISC_226 (db9) pin 5 not tied to shield, signals good
ISC_356 (db25) pin 13 IS tied to shield, signals good
ISC_223 (db25) pin 13 not tied to shield, signals good (older cable)
ISC_224 (db25) pin 13 not tied to shield, signals good (older cable)
ISC_225 (db25) pin 13 tied to shield, signals good (new cable)
ISC_227 (db25) pin 13 tied to shield, signals good (new cable)

EOM RF Signals:
At Rack, all RF signals shields are tied to rack ground.
Cable runs are isolated from rack and chamber ground
At Chamber, all RF signal shields are tied together in chamber possibly at EOM.

IOT2 Table Enclosure:
Picomotor Cable - pin 13 tied to shield, signals good.

h1susb123 accumulated 4 DAQ CRC errors on the 1-leg overnight as reported by DC1, but none on the 0-leg.

All 4 models on h1susb13 increment their CRC counters at the same time. Normally we have zero CRC errors for weeks/months across the board.

I have cleared the CRCs and we will see if this trend continues.

Picket Fence earthquake early warning system can't connect to station "UO_TOOM:HHZ", so we're only monitoring on four out of five stations.

Now that HAM7 is at sufficient pressure (6.4E-7 Torr as of this post) we helium leak checked the two re-installed 12" CF blanks removed for table locking and the entire relay tube assembly which had been removed for the viewport adapter on HAM5.

The Helium background was unstable, so we turned on the HAM7 cleanroom (on 2/18 afternoon) to help flush the area of helium overnight.

Today the background stabilized around 1.5E-10 Torr-l/s, so we were able to continue leak checking. No significant helium signal observed above the leak detector background which hovered between 1.5&2E-10 Torr-l/s during leak checking. 

HAM7 continues to pump down with the turbopump, next steps are chamber RGA scans.

Rahul, Fil, Oli

We still don't know why PM1 looks different now than it did when we installed it back in May 2025. Currently, we've nailed it down to two possibillities: (1) there's an issue with PM1 somewhere between the satamp and the in-chamber stuff, or (2) the December 2025 satamp swap to a modified satamp changed the magnitude of PM1 (we are not sure if this makes sense).

Here are some measurements we took yesterday and the things we've looked at so far.

Satamp

We were worried about the satamp, which is a dual satamp, swapped in in December 2025 (88590), with JM3 taking up the other half, so I took some transfer functions yesterday morning for both PM1 and JM3. I compared JM3 now to how it looked when we first installed it in December 2025, and it looks exactly the same, no drop in magnitude for JM (JM3 Dec2025 vs Feb 2026), and no increase in magnitude for PM1 (PM1 May 2025 vs Feb 2026).

Fil then swapped all the PM1 cables on the satamp with all the JM3 cables on the satamp. This made it so the only difference between the previous and these measurements is the part of the satamp used. These measurements for PM1 and JM3 still looked the same as the earlier measurement, so it's not the satamp (PM1 JM3 comparison). These comparison plots really show how much PM1 changed compared to JM3.

All other in-air electronics

The only other difference from the measurements last May for PM1 should be the coil driver, since the other one failed (88998). The new coil driver is modified, just like the old one, and is being correctly compensated for in the coil drive filter banks. To check this, as well as the rest of the in-air electronics, Fil swapped everything back to nominal EXCEPT for the cables that run from the sat amp out to the chamber. This way, JM3 is using the in-air electronics from PM1, and PM1 is using the in-air electronics from JM3. I did a few transfer functions looking for any difference but both suspensions and electronics chains still look the same(PM1 L, PM1 P, JM3 P). This could mean that the issue with PM1 is due to something in the satamp-to-chamber cable or in vacuum.

OSEMs

We checked the spectra for the PM1 BOSEMs but we did it while the purge air was up, so they're very noisy and not very useful.

Satamp question

The only other thing we can think of that could've changed the magnitude of PM1 but not affect what we're seeing in JM3 would be due to the satamp swap in December. The new modified satamp was hooked up to PM1 and JM3 on December 18, 2025 (88588). JM3 was first tested the next day, and obviously we never got a measurement of JM3 with an unmodified satamp, so if it's possible for the satamp to change the magnitude of PM1, that might be what is happening. I haven't had time yet to check whether other suspensions show anything like that.

Measurement info
PM1
2026-02-18 1600
- ISI Locked
- alignment offsets OFF
- DAMP OFF for measured DOF, ON for other DOFs
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-18_1600_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12905
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-18_1600_H1SUSPM1_M1_ALL_TFs.pdf
12909

2026-02-18 1715
- satamp inputs swapped with JM3 (tfs look the same)
- ISI Locked
- alignment offsets OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-18_1715_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12906
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-18_1715_H1SUSPM1_M1_ALL_TFs.pdf
12909

JM3
2026-02-18 1600
- ISI Locked
- DAMP OFF
- alignment offsets OFF
- DAMP OFF for measured DOF, ON for other DOFs
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-18_1600_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12904
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Results/2026-02-18_1600_H1SUSJM3_M1_ALL_TFs.pdf
r12908

2026-02-18 1730
- satamp inputs swapped with PM1 (tfs look the same)
- ISI Locked
- alignment offsets OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-18_1730_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12907
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Results/2026-02-18_1730_H1SUSJM3_M1_ALL_TFs.pdf
r12908

Comparisons
PM1 May 2025 vs PM1 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_PM1_May2025vsFeb182026_ALL_TFs.pdf
r12911

JM3 Dec 2025 vs JM3 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_JM3_Dec2025vsFeb182026_ALL_TFs.pdf
r12912

JM3 Dec 2025 vs JM3 Feb 18 2026 vs PM1 May 2025 vs PM1 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_PM1_JM3_PM1looksdifferent_ALL_TFs.pdf
r12910