Sheila, Begum, Camilla, Fil, Dave, Erik

Day 2 of the HAM7 work, follow on from 90426. The CDS/EE team fixed the FC1 top mass, unsure how. We found we then could not trust the sliders at all. We reverted all optics (apart from FC1) to the 90183  time. We tired putting the FC1 M3 WIT back to this time but the beam clipped on the OPOS.

Then we moved FC1 to center the IR on the SQZT7 irises. Got perfectly centered on far iris, a little high on iris at the bottom of the periscope.

Begum and Sheila then moved the ZM4 iris to mark this alignment.

TITLE: 06/02 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM3 FAROing finished, HAM2, BBS, and SPI work continue. The LVEA is in LASER HAZARD.
LOG:

• FC1 issues were investigated (FRS38162) and fixed.
• 19:53 UTC sush7 restart
• 21:15 UTC Transition to LASER SAFE for Jim to lock ITMX ISI then back to HAZARD
• 22:50-23:05 UTC Periodically I saw seeing red blocks flashing around the COIL OUTPUT FILTER boxes on M0 and M1 for ITMY, I'm guess this was from the crew installing baffles making the osems angry.

Jennie Wright

Summary: Started debugging JAC WFS, two corrections made in WFS segment -> euler basis matrix.

Not sure if this change was made by the power outage or it has been set up wrong the whole time but the channels for segment 3 and 4 in the Q phase matrix for both JAC WFS QPDs were wrong.

This meant yaw = + segment 1 - segment 2 + segment 3 - segment 4 which would be some kind of weird pringle mode.

I corrected the sign, and also updated the note at the bottom right of the JAC_WFS_SETTINGS screen to reflect the sign that the WFS should have (the previous note here described the IMC WFS euler basis as I had copied the medm screen from the IMC custom screens).

now yaw = +1 -2 -3 + 4.

NB: JAC WFS euler basis matches other ASC QPDs but the IMC has P & Y swapped due to the persicopes in HAM2 and so has yaw = +1 + 2 -3 -4 and pitch = +1 -2 -3 +4.

New values for Q matrices are accepted in sdf, as is the PSL PZT mirror offset values that align the beam to the JAC as this has changed since it was last set before the power outage.

Summary: The QOSEMs on the BBSS will see a vertical sag of ~50um. The LF and RT QOSEMs should be offset 50um low of center in there x axis, and the F1, F2, F3, SD QOSEMs should be offset 50um low of center in there y axis; such that they will be well centered when under vacuum.

In T2600176 (write up to come) we calculate the expected vertical sag of the BBSS suspension chain to be 58um at M1. This is slightly larger than the 50um predicted for the BSFM (T1100616), which is consistent with the fact the payload is lighter. To verify these calculations, we pulled OSEM data from the last pump down of the BSFM (April 26 2025 = 1428872333)), and see that there was a vertical sag on the LF and RT BOSEMs of ~35um. See the figure attached.

This is about 10um less than predicted by the calculations for the BSFM, a trend which is also seen on the Quads (LHO alog 15887). As such we suggest that the BBSS should have its M1 QOSEMs offset by ~50um low of center, also about 10um less than the theoretical value. The M2 and M3 OSEMs do not need to be offset, as they don't measure in the vertical direction.

A. Effler, R. Schofield, R. Short

This morning, we started working in BSC1 to prep for the new cage baffle installation on ITMY. Before going into any chambers, Anamaria and Robert moved ITMY to center the OpLev signals. Once at BSC1, Anamaria and I were in the chamber while Robert handled tools in and out as well as kept an eye on particle counts. We started by attaching the long locker bracket on the arm cavity baffle (ACB), then pushed the ACB up and away from the quad after undoing the hinge assembly. While holding the ACB up, we inserted and screwed in the wedge that keeps the ACB away from the quad. With this out of the way, we locked down the bottom two stages of both the main and reaction chains of ITMY by pushing in the earthquake stops until they just came into contact. We then went about replacing the stops on the HR surface of the ITM. After this, we realized that we meant to get measurements of the test mass and reaction mass before they were locked down, so we unlocked the bottom stages of each chain so they were free hanging and took measurements, then re-locked the stages. At this point, we stopped for lunch.

Ibrahim, Tom, Oli

Yesterday we were able to take our first set of transfer functions with the QOSEMs! They are looking good. The measurement files can be found in /ligo/svncommon/SusSVN/sus/trunk/BBSS/H1/BS/SAGM1/Data/2026-06-01_1700/2026-06-01_1700_H1SUSBS_M1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml. I have committed the data files to svn as r13024, but I have not yet exported them or analyzed them in matlab because I want to make sure I do it the same way that LLO has decided to do it.

Tom, Ibrahim, Oli

Yesterday we made a lot of progress on the BBSS, specifically on the QOSEMs.

First, we went around between all the QOSEMs and worked on centering in the X and Y directions. Once we got everything within +/-1000 counts, we made sure the cam adjusters were all tightened. We did this with the constant current switched ON for all the QOSEMs at the satamp, and with the whitening OFF on the satamp but had the compensation ON in medm.

Then we left and were ready to try damping and transfer functions.

We switched the constant current OFF for the QOSEMs now, since we wanted the satamp to be able to adjust the currrent to keep it the same. We also ended up needing to turn the whitening compensation OFF in the model to be able to see the actual amount of movement since it had also been OFF at the satamp.

While trying to damp, we found that we needed to swap the sign of the damping gains to get damping to work. We believe this is because these QOSEM coils, which were made out of older BOSEMs, had the opposite wires from normal connected up, leading to the current flowing the opposite way than expected.

We also needed to lower some of the damping gains.

I've attached a screenshot of how our damping filter bank looks now, but it seems to be working well!

Yesterday I made some changes to the h1suslo12 model(before, after). We were now done with the BOSEMs on the BBSS, so we needed the BBSS model to be able to drive to the DAC for M1 so we could test the QOSEMs. We also needed to be able to switch the BIO on the BBSS, so we also needed to connect the BIO senders and receivers back up to be able to communicate with MC2, which controls the BIO switching for the b2h34 models.

To be able to run this updated model, we would also need to stop the h1susbs model so there wouldn't be mulitple sets of channels trying to write to the same DAC.

Erik and Jonathan (90422) helped with stopping h1susbs, and with building and restarting h1suslo12.

J. Kissel, S. Koehlenbeck (in person!)
D2400107 for the annotated layout of SPI Pathfinder ISIK's Transceiver Assembly.

After an easy recovery from other-the-weekend, site-wide power outages (LHO:90413), we resumed last week's investigations of what might be causing the MEAS IFO to drift (LHO:90382).

%%%%%%%%%%%%
Executive Summary: No magic bullet found. Today we ruled out the collective idea we all had that the picomotor-actuated mounts were the problem (LHO:90384) by replacing every pico-actuated mount with manually driven mounts. We also replaced the last optic we hadn't swapped in the MEAS path to the MEAS IFO -- M_B1. No impact -- we still see the MEAS IFO alone drift.
%%%%%%%%%%%%

It was only a half-day of forward investigative progress given the power outage, but having Sina on-site really helped confirm my (in)sanity and accelerate investigatory iterations.

Upon arrival in the lab Sina re-confirmed my construction and alignment of the D2400107-v5 board and the quality of things:
    - Centering on optics with IR card :: good.
    - Centering on photodiodes with IR camera :: good.
    - No stray beams (even from what would be AR coatings of beam splitters) :: good.
    - The as-we-left-off Friday assessment that with M_M2 and M_B4 down-graded to manually driven mounts, we still see drift.
    - Having one or the other REF or MEAS beam into the MEAS IFO blocked, that the power on each beam is stable without drift.
    - After an alignment drift, quickly touching the alignment of all three M_M2, M_B4, and M_M1 cannot recover the MEAS IFO efficiency.

As we continue to grasp at straws, we replaced the last optic in the MEAS path into the MEAS IFO -- M_B1. This optic splits the MEAS beam on the board feeding it to the MEAS and REF IFOs, so we were hesitant to swap it. But now that we're getting so good at re-aligning the board after changing out optics (once optic is placed, re-alignment can be done within 2-5 minutes), we figured we must. 

So, all at the same time, we
    - unlocked all manual drive set-screws on all optics (recall the REF path had been "locked down" the day I'd gotten ~95% efficiency),
    - loosened and re-tightened R_B1's 1/4-20 bolt that secured the mount to the breadboard. It wasn't "loose" but it wasn't "cranked on" either.
    - Replaced M_B1 optic 
    - Replaced the M_B1 manual-drive pitch actuator's 1/4-100 alignment screw and bushing because it was "crunchy" and "stiff" to use. This had been this way, but when I was driving solo I'd suffered thru it and locked it down the day I got 85% efficiency on the MEAS IFO and didn't look back. Now what we're touching the mount anyways, we figured we might replace it in case the issue was some sort of stick-slip thing happening.

Upon doing all these things ... things looked solid for ~10 minutes... and then the efficiency started to drift again. Especially after turning on the Clean Room fans.

This again resurrects the theory we thought debunked: "it must be the environmental conditions..."
Why did we rule this out before?
    (1) The REF IFO does not see any drift. Ever. The board is so small and so local, and both IFOs are sampling the same beams. *Very* hard to believe that the few differences in paths and path lengths would cause only ONE of the IFOs to drift. The environment should impact both IFOs equally.
    (2) We *do* see phase noise when we make environmental changes -- as expected. Path length differences caused by
         - physically manipulating the board, its mounts, or optical fibers,
         - waving hands over the board
         - talking, even at a medium volume
    (3) Any environmental change in the efficiency we can cause -- be it: 
         - clean-room fans ON/OFF, 
         - clean-room or room lights ON/OFF, 
         - people coming in-and-out of the clean room, 
         - standing in different positions around the optical table
        -- they all only some-times seem correlated, and never is it reproducible.

But we've run out of things to change, so today we're going to try to adjust the environment and/or other things that *should* be common to the IFOs:
    (a) We're gunna being in an incandescent lamp to try to create thermal gradients
    (b) We'll put on our tin-foil hats and enclose the breadboard in a temporary foil enclosure
    (c) We're try adjusting the NPRO seed laser controller's parameters (like diode temperature)
...and keep trying all the other wild theories we can concoct.

TITLE: 06/02 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: MAINTENANCE
    Wind: 8mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.14 μm/s 
QUICK SUMMARY:

• FAROing on HAM3, HAM2 work, and HAM7 continues
• DAQ_KCO channels are disconnected

Yesterday (June 1) I replaced a failed power supply on the Comtrol communication device at EY that bridges a dust monitor and a weather station to the network.

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

Today started with removal of the HAM7 +X and -Y doors, WP 13283.  These were already on 4 bolts/piece, so removal was relatively quick.  Nothing to note other than the usual O-ring sticking business. The 2x 12" CF blanks on the +Y door were also removed for ISI locker access.  Since the final cleaning happened ~1 hour from door removal, particle counts were very minimally elevated, 40 @ 0.3um and 20 @ 0.5um (see pic).

We then moved on to the X-beamtube manifold vent work, WP 13284.  The X-manifold turbo pump was valved out.  We then cycled GV7 open, then hard closed again.  The GV opened at 10 psi, and hard closed at 20 psi, so we believe the piston O-ring replacement is working well.  Then, the X-manifold vent was started.  After burping the system a few times and confirming there was no communication past GV7, we started venting the manifold section.  We noted that the Kobelco's duty cycle seemed to increase audibly as the pressure in-vacuum rose, which isn't surprising given that we have 7 doors and 2x 12" ports open on the corner volume, so we elected to keep the vent slow, maybe 5 torr/minute.  We stopped the vent for the night at around 400 torr.  Tomorrow, we'll finish venting and open GV2.  

After JAC was recovered (alog 90421) we moved IM4 by negative 500urad YAW (from -387.1urad to -887.1urad) and adjusted PRM so that it retroreflects (without bothering to adjust IM2, 3 and 4 in the interest of time) and Jenne started centering the REFL A and B using RMs.

However, RM2 still railed.

Turns out that the accuracy of retroreflection matters because 100urad rotation of PRM causes the equivalent of 280urad rotation of IM1 as far as the beam angle leaving RH9 (IFO REFL pickoff) is concerned.

The retroreflection technique was nothing sophisticated, we used an IR card with a hole, put the card between the IFI output baffle and DKDP baffle, put the forward going beam in the hole in the card so it goes through. Rahul would make a huge (like 1.5mrad) YAW rotation for PRM, first positive YAW to find the reflected beam on one side of the hole in the card, and then negative YAW to find it in the other side of the hole, and find a good PRM YAW offset where the reflected beam for +1.5mrad positive and negative offsets are balanced on the card. The retroreflection accuracy is no better than +-500urad.

Anyway, using this technique we moved the PRM slider offset to [P, Y]=[-1165, +1000] (from [-1165, 20.5]).

Out of curiousity I changed the YAW offset of PRM from +1000 to +700 so [P,Y]=[-1165, +700], used RM1 to center REFL_B and RM2 to center REFL_A and it was easy without railing RM2 nor RM1. See attached.

I'll  see if there's a space for an iris on IFI where both faces are clearly visible. If so we can probably use an IR sensitive camera as a better resolution viewer, center the iris for the forward going beam well, and observe the centering of the return beam on the iris.

(However, it's still a good idea to reduce the output impedance of the RM OSEM coil drivers. Small actuation range is fine if things are working well, but they're not.) 

Jim, Shoshana, Alexandra, Arnaud

Today we continued setting up the H2-PSL lab to start the testing the HOQIs.

* Received and moved the laser system (RIO+Laser Driver+TEC), and readout (HOQI TIA) in the H2-PSL (see picture 1) 
* Gathered needed electronics from the EE shop (See list below) and plugged them in the lab
* Bagged and tagged the peek HOQI components from VPW (waveplate holders, photodiode holders, in-vac cables)
* Visually inspected the new batch of 10 flexures after c&b (see picture 2), and brought them to the H2-PSL (no issues found so far)
* Started setting up the Panasonic optical readout for CRS balancing. We will need some basic components from the optics lab to hold this readout.

Items borrowed from the EE shop :

x2 GWINSTEK power supply
x1 Hewlett P power supply
x1 multimeter with probes
x1 Techtonik oscilloscope 
x1 Bnc banana plug
x4 bnc to clips
x4 bnc cables
x1 db9 cable
x3 power cables
x3 breakout boards (x2 db9 and x1 db25)
x3 db9 gender changers

Sheila, Camilla, Disha

After Jim locked the ISI, Marc bypassed the high voltage interlock, and Camilla restored the psams, we reset the alignment sliders following 90483 which was in air.   The dither locking worked without any issue, and we saw that the beam was low on both the irises in the homodyne path on SQZT7.  Camilla adjusted the alignments of ZM4+ZM5 to center the beam on the irses, screenshot attached shows the alignment that she found.  

We placed an iris in front of ZM4 for this alignment, we were able to look from the +X side of the chamber to check the centering.  We also took photos of the IR/green co-alignment, it looks good coming right off the VIP, but looking right after ZM3 you can see that there is a small misalignment in yaw.  We will continue with placing irses tomorow.