aLIGO LHO Logbook

H1 ISC - Comment to Saturday morning: pico holder on the WFS sled for 50:50 splitter was loose (JennieW, Jason, Keita)

keita.kawabe@ligo.org — Sat, 28 Mar 2026 22:17:32 -0700

Author: keita.kawabe@ligo.org

Report ID: 89687

New_ASC_REFL_A_angle.jpg: After I rotated the ASC-REFL_A angle clockwise seen from the top by about 10 degrees or so.

1inLSC_vert.jpg shows the centering on the 1" lens for the LSC REFL. You cannot judge horizontal centering from this picture due to parallax but it looked OK to me.

2inOnSled_hor.jpg: Centering on the 2" lens on the REFL WFS sled. Horizontally it's somewhat to the left (+Y) but not too bad. You cannot judge vertical centering due to parallax but it looked OK. See the 1" lens on the sled.

1inchOnSled_hor.jpg and 1inchOnSled_vert.jpg: Centering on the 1" lens on the sled. Vertically it's quite good. Cannot tell much horizontally due to parallax, but it looked a bit off to +Y direction to me. Not too bad.

LSC_REFL_A_ghost.jpg, LSC_REFL_B_ghost.jpg, WFSA_ghost.jpg, WFSB_ghost.jpg show that reflections from all REFL sensors go to corresponding beam dump.

(The last picture (POP_stiffener_base_touching_.jpg) shows how the POP periscope stiffener base touches the base of the REFL path BS that splits the beam to the in-vac and air path. So, this could have made a very minor change mostly in YAW. But anyway it's without doubt that the loose mount on the REFL WFS sled was the main cause of the trouble.)

Images attached to this report

H1 ISC - Comment to Saturday morning: pico holder on the WFS sled for 50:50 splitter was loose (JennieW, Jason, Keita)

keita.kawabe@ligo.org — Sat, 28 Mar 2026 17:08:45 -0700

Author: keita.kawabe@ligo.org

Report ID: 89686

Afternoon: Done with the REFL path

Making sure that the beam is centered-ish on the LSC sensors

We enabled the WFS DC centering, relieved the WFS output by RM sliders, disabled the WFS centering. Then scanned RM1 in PIT to find out where the LSC REFL A and B DC starts to fall off, and make an average position in terms of RM1 PIT offset ("plateau center"). In general the plateau center is not the same as WFS DC center.

Use the common pico for the REFL LSC sensors to make the plateau center come closer to the WFS DC center. See the 1st attachment.

Repeat the same thing for YAW. We noticed that LSC REFL B is not exactly the mirror image of REFL A, mostly horizontally, as you can see from the 2nd attachment. If they are, we expect both to start falling at the same time but they don't. To fix that we need to touch up the non-pico 50:50 splitter that steer half of the beam to REFL B, but we chose not to do it because the scan range you see here is huge, and beam will totally fall off of WFSB before LSC REFL A and B starts falling.

After all of these and minor tweaks here and there, we ended up with: RM1 P = -196, Y=281, RM2 P=910, Y=-490.

Tilting WFSA in YAW

I checked the beam position along the REFL path and unfortunately the reflection from WFSA was hitting the mirror mount. I tilted the WFS clockwise, paying attention NOT to change the optical path length significantly. After this, Jason and Jennie used pico to steer the beam back to the center of WFS. I confirmed that the WFSA reflection goes into the beam dump.

Final check

I rechecked the beam position along the REFL path. Nothing was grossly off-centered except for 1" mirrors and BS on the WFS sled (this was always the case).

On M2, RM1 and M5, the beam position looked OK though it was hard to say anything quantitatively. No picture for these.

1" lens for the LSC censors, 2" lens on the WFS sled as well as 1" lens on the WFS sled looked good.

Reflection of all LSC and ASC REFL sensors fall on the beam dumps.

Pictures will follow.

No POP check yet

I looked at the POP path too but it wasn't flashing and it was already 4PM so we gave up. We'll continue on Monday.

Images attached to this report

H1 ISC - Saturday morning: pico holder on the WFS sled for 50:50 splitter was loose (JennieW, Jason, Keita)

keita.kawabe@ligo.org — Sat, 28 Mar 2026 13:49:06 -0700

Author: keita.kawabe@ligo.org

Report ID: 89685

I've found that the pico mount for 50:50 BS on the REFL WFS sled in front of ASC REFL_A was loose and rotated counter-clockwise seen from the top by a huge amount (1st attachment, orange arrows show the direction of rotation). Our guess is that the BS mount was bumped when we were leaning into HAM1 from -Y door to work on the JAC output periscope. In general, it's hard to rotate the mount clockwise seen from the top even if the screw is not super tight (because the screw tends to be tightened), but it's easier to go counter-clockwise.

When this was found, the beam was hitting the +X-Y edge of the mirror, there was no clear reflection beam found so no beam on WFSA, but somehow the ugly transmission beam with lots of diffraction patterns was making it to WFSB.

We reverted the RM1 and RM2 bias sliders back to O4 level (RM1 PIT=-180, YAW=-57, RM2 PIT=890, YAW=-530) and I confirmed that the centering on the 2" lens was good. WFSA mount was screwed down tight to the post.

RM1 bias was adjusted further (RM1 PIT=-190, YAW=263) to roughly center the beam on WFSB.

At this point I looked at the beam on WFSA and it was still off mostly in YAW but there was also a large PIT offset. These were taken care of by adjusting the picos I've just screwed down.

I enabled the REFL WFS centering which worked right away. LSC REFL diodes are receiving almost equal amount of light. We'll have to make sure that the beam is not clipped on LSC diodes. Anyway, I relieved the ASC using RM sliders and ended up these numbers: RM1 PIT=-192, YAW=274, RM2 PIT=910, YAW=-532.

INS, IOO, ISC

Images attached to this report

Non-image files attached to this report

PXL_20260328_172117447TS~2.mp4

H1 CDS - Comment to alarm handler is beeping about H1:PEM-CS_DUST_LAB2_300NM

david.barker@ligo.org — Sat, 28 Mar 2026 10:21:29 -0700

Author: david.barker@ligo.org

Report ID: 89684

Not sure why this would be alarming today, it has been invalid for many weeks. The 0.3um raw counts went from 0 to 30 last Sunday 15:34 22mar2026, but it looks like the calibrated counts-per-cubic-foot has been NAN or INF for a very long time, which is why it cannot be trended with ndscope.

Perhaps the alarms system was recently restarted and DUST2 is regularly acknowledged on startup?

Images attached to this report

LHO VE - Sat CP1 Fill

david.barker@ligo.org — Sat, 28 Mar 2026 10:13:31 -0700

Author: david.barker@ligo.org

Report ID: 89683

Sat Mar 28 10:07:24 2026 INFO: Fill completed in 7min 21secs

Images attached to this report

H1 CDS - alarm handler is beeping about H1:PEM-CS_DUST_LAB2_300NM

keita.kawabe@ligo.org — Sat, 28 Mar 2026 09:23:31 -0700

Author: keita.kawabe@ligo.org

Report ID: 89682

We're getting <HIHI, MAJOR> alarm about H1:PEM-CS_DUST_LAB2_300NM_PCF, which I cannot trend using NDSCOPE, but I can plot H1:PEM-CS_DUST_LAB2_300NM_RAW and that number has been 30[V?] for the past 6 days.

I've silenced it but could somebody check?

CDS, OpsInfo

Images attached to this report

H1 IOO - Comment to Re-aligned JAC IOT1 table with HAM1 in air

jennifer.wright@ligo.org — Fri, 27 Mar 2026 17:44:27 -0700

Author: jennifer.wright@ligo.org

Report ID: 89681

I turned the power down to 100mW at the end of the day using the rotation stage.

H1 ISC - Alignment to get PRX flashes

jenne.driggers@ligo.org — Fri, 27 Mar 2026 17:43:57 -0700

Author: jenne.driggers@ligo.org

Report ID: 89679

[Jenne, Jennie, Keita, Jim, Sheila, Betsy]

Sum up: We're aligned pretty similarly to a reference time of [ 14 March 2026 02:20:00 UTC ], which is an "IR Found" time in between DRMI locks. We're back in the same place on IM4 Trans QPD as well as both forward-going POP QPDs. We have some mediocre PRX flashes. We are back (in the REFL path) on the same 3 of 4 PDs that we were before re-venting, so we should be in a good place for the team to work on REFL path things tomorrow.

Some details:

Ref time for all optics *except* PRM is [ 14 March 2026 02:20:00 UTC ]. For PRM I take 20 mins earlier, at [ 14 March 2026 02:00:00 UTC ], when DRMI was locked.
- This ref time is when IR was found in the arms during main locking sequence, in between 2 DRMI locks, so the alignment should be overall pretty good.
First I put all the optics [IMC, IMs, PRs, ITMX] back to their top mass osems (after figuring out that the DAC Kill was killed, alog 89676).
Jim isolated HAM2's ISI. Jim had to unlock HAM3 HEPI to get HAM3 ISI isolated.
I touched up optics to top mass osems again.
Once JAC was locked, I got IMC locked. After the IMC ASC converged, I moved MC1 so that it was back to its OSEM place, which moved MC3 farther from its reference osem place. So, modulo HAM2 ISI slight change, the IMC is back to where it was I think.
I then adjusted IM3 to get back to the reference time's place on IM4 trans QPD.
I then adjusted IM4 to get back to the reference time's place on the two POP QPDs (they both were happy at the same time).
This already gave pretty okay PRX flashes.
I moved SR2 to get centered on AS_C. However, I hadn't checked the BS or SR3.
I tried improving the PRX flashes a little with PRM, but wasn't making tons of progress. May need a bit of touching IM4 / PR2 in addition to PRM?
We're seeing DC light on ASC_REFL_B, as well as both LSC_REFLs (although less on LSC REFL B than LSC REFL A). I have not checked or touched the RMs.
Being on the same 3 PDs that we were while under vacuum gives us confidence that we're in a good place at least for fixing up the REFL path.
The Saturday team may try locking PRX, or may defer to Monday. Either way, fixing up the POP path will probably happen after the REFL path.

The 4 attachments have vaguely descriptive names. The one from March 14th is my reference time, and then probably the other one that is useful to look at is the End of Day where I left things. I'm not sure I was seeing PRX flashes at the very very end of the day, so PRM might need some adjustment in the morning. The other two attachments are showing where the suspensions were before I started, as well as showing that I first got back to the reference time osem positions.

SUS

Images attached to this report

H1 IOO - Re-aligned JAC IOT1 table with HAM1 in air

jennifer.wright@ligo.org — Fri, 27 Mar 2026 17:42:09 -0700

Author: jennifer.wright@ligo.org

Report ID: 89680

Jennie W, Keita, Betsy, Jason,

Betsy and Jason rolled up IOT1 this afternoon and Keita tweaked the alignment from the top periscope mirror to the DCPDs with the PSL output at 2W. He also re-aligned the trigger PD.

We can now lock JAC in air with the double door cover so we can have the light exiting the chamber but most of the door covered above and below where the beam exits.

I had to run the 'normalise signals guardian state after we closed the table and turned the light off, probably because the signal on REFL PD changed.

We left the light pipe closed and both doors covered at the end of the day.

NB: I accidentally pinged the HAM1 -Y side large table beam dump plate (the one that would catch the scatter from the JAC REFL viewport) with one of the small paper clips we use to hold the two door covers to each other. I will wipe this down tomorrow.

ISC

H1 ISC - OMCA and OMCB flashing, OMCB path needs more work

elenna.capote@ligo.org — Fri, 27 Mar 2026 17:34:26 -0700

Author: elenna.capote@ligo.org

Report ID: 89674

Today, Keita and Oli turned up the power to the fiber again so we are getting about 30 mW out. This is enough power that you can see the beam transmit the input coupler of the OMCs easily on a card. With the room lights dim, you can see flashing of the beam at both DCPDs with a card. Using the IR sensitive camera, we are able to fine tune the input alignment further.

The beam has been well-aligned to OMCA, and the flashing present at the DCPDs looks mostly like mode mismatch, which makes sense because we made no effort to mode-match our input beam to the OMCs.

The beam alignment to OMCB still needs some work. It looks predominantly like a yaw misalignment, so we need to make some finer adjustments of the upstream optics.

Since all of the BHSS optics have been pre-angled using the clocking tool, I followed the map on slide 86 of T2100190 to place the lenses, mirrors and beam dumps. Just by eye, I can tell we will need to fine tune this alignment further once we have laser beam. I was unable to place one beam dump because it goes roughly where we are pooling the OMCA cables. Once we can route and clamp those cables properly, there will be room for the dump. I haven't placed the QPDs yet, they are still bagged. I also placed the three head optics randomly, since they can't be placed until the OMC iris template is removed.

As a reminder, the order of operations here is to use the iris alignment template to get good input alignment to both OMCs. Then, this template is removed so we can use other precision templates to align the three optics that go at the head of the manta ray: mirrors A/B-R1 and 36-R1. Then, we can finish the rest of the beam paths to the OMC QPDs.

I took a phone video of OMCA flashing and managed to screengrab these two photos from the videos: DCPDA, DCPDB

SUS

Images attached to this report

H1 SQZ - Looking at SQZ beam today, refl beam shape varies with ZM2 psams

sheila.dwyer@ligo.org — Fri, 27 Mar 2026 17:12:17 -0700

Author: sheila.dwyer@ligo.org

Report ID: 89675

I returned to the slider positions where we had good green and IR flashes in the filter cavity from Wed 89629. Since this time of good flashes the H:M2 pico was reverted to 0 (it's setting during in chamber work), so the green flashes weren't as high as they were on Wed. Screenshot attached here. In this alignment I went to SQZT7 and looked at the green reflection, it looks like an oval but is coming to the persicope. (photo)

While at the table, I moved the picomotor for H:M2 X to -710, which is where Tony and I had put it 89596 and where we had both IR and green flashes good. I could see the beam move on SQZT7, but it wasn't a big move, and after pico'ing it looks like we still have an oval beam making it to the table.. (photo, screenshot) On the cameras we can clearly see cavity flashes in green but the IR flashes were off the camera, so I went to FCES and centered the flashes on the IR camera (using the seed). I also went back to sqzt7 and aligned the FC green refl onto the diode.

While I was there, I watched the green beam on a card while I moved suspensions to see how much freedom we have to move the suspensions and still get the green beam out of the viewport. I could move ZM1,2,3 and FC1 by a couple hundred urad in both pitch and yaw (although not in either direction), so there is a reasonable adjustment range. Moving these didn't impact the oblong shape of teh beam, so it doesn't seem like that is caused by clipping. I then moved the ZM2 psams settings, and saw a big change in beam shape, it became more round looking on a card for strain guages of 4.15 or 5.15 (our usual setting is 3.15).

I left the alignment back at the one that gave good flashes for IR and green (up to 10, is off in pitch), and with the CLF IR flashes are max 0.15 counts.

Images attached to this report

H1 General - OPS Friday Day shift summary

ryan.crouch@ligo.org — Fri, 27 Mar 2026 16:29:32 -0700

Author: ryan.crouch@ligo.org

Report ID: 89665

TITLE: 03/27 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: The +/- Y doors were taken off HAM1 this afternoon alog89672, See Jims' alog89673 for the current CS seismic configuration. I'm not sure if the intercom is working, I didn't hear myself after plugging it in and trying the offices. THe LVEA is now is LASER HAZARD, as is the optics lab.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:28	FAC	Kim, Nellie	LVEA	N	Tech clean, Nellie out @ 15:12	15:19
14:58	FAC	Randy	LVEA	N	Prep for door removal	15:26
15:51	VAC	Travis	LVEA	N	Check HAM1 purge air	15:57
16:05	FAC	Mitch	LVEA	N	Cleanup in the Wbay	16:22
16:07	EE	Fil, Marc	LVEA	N	Cable pulling for moving electronics, HAM3/BSC2	17:09
16:22	VAC	Nellie	LVEA	N	Tech clean	17:11
16:36	VAC	Gerardo, Randy	LVEA	N	HAM1 door removal! Travis to join	18:33
16:41	FAC	Jason	Optics lab, LVEA	LOCAL/N	Property hunt	17:21
16:50	VAC	Betsy, Mitch, Travis	LVEA	N	HAM1 doors, Mitch Betsy out 1700	18:30
16:51	FAC	Kim	LVEA	N	Tech clean	17:44
17:02	SEI	Jeff, Sina	Optics lab	LOCAL	SPI work	18:07
17:03	BHD	Oli	Optics lab	LOCAL	BHSS work, magnet pol checks	20:16
17:12	EE	Fil, Marc	MidY	N	Cable search	19:53
17:32	OPS	Ibrahim	Optics lab	N	Put away parts before curtains	17:46
17:35	FAC	Jason	PCAL lab	N	Property inventory	17:39
17:38	OPS	Betsy, Jim	LVEA	N	Cleanroom move by HAM1, Betsy out 1746	18:43
17:53	EE	Thomas	Vac Prep	LOCAL	In-Vac cables	19:19
18:32	SUS	Ibrahim	Vac-Prep	LOCAL	Joining Thomas	19:19
18:55	BHD	Elenna, Keita	Optics lab	LOCAL	BHSS, Keita out 19:37	20:16
19:20	SEI	Jim, Betsy	LVEA	N	LOCK HAM1 ISI	20:07
19:43	FAC	Randy	LVEA	N -> Y	Work on emod, handrails	22:46
19:49	SPI	Jeff, Sina, Jason	Optics lab/PSL encl	LOCAL	Measure fiber power, in lab checks then PSL enc checks, Jason out of PSL at 20:40	21:25
19:53	EE	Fil, Marc	LVEA	N ->Y	Cables, all around HAM3 and BSC2	23:10
19:56	SQZ	Sheila	LVEA	LOCAL	turn on SQZ laser, potential transition to hazard at SQZT7	20:06
20:11	EE	Ibrahim, Thomas	Vac Prep	N	In-Vac cabling	20:18
20:37	EE	Ibrahim, Thomas, Sophie	Vac Prep	N	In-Vac cable making, Ibrahim 23:15	Ongoing
20:20	ISC	Betsy	LVEA	N	Look into putting tables back	21:39
20:48	ISC	Sheila	LVEA	N	Talk to Fil and Marc, Turn on SQZ laser	21:03
21:02	TCS	Sophie	Vac prep	N	CHETA work	22:56
21:22	ISC	Betsy	Optics lab then LVEA	N	Parts/tools checks then LVEA	21:56
21:22	VAC	Travis, Bram	LVEA	N	Look at laser stop buttons	21:27
21:24	BHD	Elenna	Optics lab	LOCAL	Turn on the laser, cont BHD work	Ongoing
21:31	OPS	Sheila	LVEA	N -> Y	Laser Hazard transition	21:47
21:58	SQZ	Sheila	LVEA	Y	SQZT7 work, alignment	22:15
21:59	OPS	Jenne	LVEA	Y	Look for Fil/Marc	22:14
22:06	ISC	Keita, Jennie, Betsy	LVEA	Y	HAM1 work	Ongoing
22:08	SEI	Jeff	LVEA	N	Find part	22:28
22:09	ISC	Jason	LVEA	Y	Join HAM1 team	22:21
22:38	SQZ	Sheila	LVEA then FCES	Y	SQZT7 check before FCES	23:06
23:21	SQZ	Sheila	LVEA	Y	SQZ7 checks	Ongoing
23:29	SEI	Jim	LVEA	Y	Unlock HAM3 HEPI	Ongoing

16:08 UTC HAM3 and BSC2 SUS to safe, their SEI states were already in safe (ISI_DAMPED_HEPI_OFFLINE, and READY / LOCKED) for Fil and Marcs cabling/electronics work
16:12 UTC SUS BS wd trip, OSEMs inputs are disconnected it looks like, came back at 21:00 UTC, the pointing still looks the same pretty much the same
18:08 UTC SPI laser shuttered in Optics lab
18:15 - 18:40 Sophie to CHETA lab
22:21 UTC BS ISI ST1,2 WD trip, CPS glitch a minute later

Images attached to this report

H1 PSL - PSL Status Report - Weekly

ryan.crouch@ligo.org — Fri, 27 Mar 2026 15:52:11 -0700

Author: ryan.crouch@ligo.org

Report ID: 89678

Closes FAMIS39757

Laser Status:
NPRO output power is 1.83W
AMP1 output power is 70.39W
AMP2 output power is 138.8W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN

PMC:
It has been locked 20 days, 23 hr 13 minutes
Reflected power = 26.87W
Transmitted power = 104.4W
PowerSum = 131.3W

FSS:
It has been locked for 0 days 2 hr and 21 min
TPD[V] = 0.4974V

ISS:
The diffracted power is around 3.9%
Last saturation event was 0 days 2 hours and 25 minutes ago

Possible Issues:
PMC reflected power is high

H1 SEI - H1 ISI CPS Noise Spectra Check - Weekly (FAMIS #39341)

ryan.crouch@ligo.org — Fri, 27 Mar 2026 15:47:44 -0700

Author: ryan.crouch@ligo.org

Report ID: 89677

Closes FAMIS39341

As expected from the vent and HEPI's being locked on HAMs 1,2,3 and BSC 2,3 the plots look noisier. I don't see any glaring issues with the other chambers.

Non-image files attached to this report

CPS_spectra_15:43-03_27_2026.pdf

H1 SUS - HAM1 DAC Kill also affected HAM2 suspensions

jenne.driggers@ligo.org — Fri, 27 Mar 2026 15:33:24 -0700

Author: jenne.driggers@ligo.org

Report ID: 89676

[Jenne, DaveB, RyanC, Jason, Betsy, Jennie, Keita, Fil, Marc]

Several folks prepping to align optics for HAM1 work noticed at about the same time that several HAM1 and HAM2 suspensions were not behaving as expected. Eg, I tried misaligning and aligning PR3, but nothing happened (I did this because the sliders hadn't changed, but the OSEM readbacks had changed). The team prepping to go into chamber similarly noticed that there were no counts going out to the IOP models.

Fil and Marc had a quick look at the sat amps for the HAM2 suspensions (just in case, even though no one had been near them), and everything looked fine.

Upon going back to the control room, I finally noticed on the CDS overview screen that IOPSUSH12 had its DAC Kill light illuminated. After some clicking around, we found the dac kill watchdog screen, and hit RESET. However, PM1's RMS was still larger than threshold, because HAM1 is at air and the purge air is on, so its undamped motion was too high. I clicked BYPASS on PM1, which let signal go through to damp PM1. PM1 quieted down, and I un-bypassed it by hitting RESET again.

At this point, it seems like all of the suspensions on HAMs 1 and 2 are again behaving as expected.

CDS

X1 SUS - HXDS - OMA2, OMA3 triples lab assembly and test stand M1 actuation measurements

ryan.crouch@ligo.org — Fri, 27 Mar 2026 13:50:05 -0700

Author: ryan.crouch@ligo.org

Report ID: 89651

Rahul, RyanC

Over the past few weeks we've prepped the two basic HXDS assembly (structure sn 035, alog88828 - OMA3 with B2-03 optic, and structure sn 029, alog87998 - OMA2 with A1-03 optic) that we received from LLO. Rahul and Camille assembled these PSAMs at CIT. We attached the wires using the provided HDS Bottom Mass Wire Plate ASSY D2000395 setting the top blade height first using the blade height gauge then feeding the wire down, and the bottom mass (PSAM) with its fixture assembly plate. The wire clamps really wanted to clock when I was doing the final turn, turn and a half on their fasteners so I had to tighten them very slowly. For OMA2 we had some trouble trying to remove the intermediate mass fixture plate D2000230 to replace it with the BOSEM Cam Adj Mtg ASSY as there was a stuck dowel pin. The fixture plate was a V1 version which did not have the emergency release feature that the later version has. We brute forced it out without damaging any components or wires but the intermediate mass shifted a decent amount despite my efforts to keep it still. OMA3 did not have this issue as it was as the V2 plate.

Once we had OMA2 fully assembled, we balanced it then brought it over to the test stand and connected the four OSEMs to the top stage. This first suite of phase 1a measurements was done without the M2 PSAMs cable connected.

The OLV counts were as follows (we later swapped LR and UR, which is reflected below) for OMA2:

UL: 28460 UR: 31900

LL: 29720 LR: 30860

The data/templates live in: /ligo/svncommon/SusSVN/sus/trunk/HXDS/X1/OMA2/SAGM1/Data

and the result pdfs are in: /ligo/svncommon/SusSVN/sus/trunk/HXDS/X1/OMA2/SAGM1/Results

I ran 3 sets of measurements on Wed with a bw of 0.02. The first measurement 2026-03-25_1730 showed some weirdness with LR and lots of cross coupling from Length into Pitch and a bit into Yaw, the shapes were a little different, as well along with the magnitude but that's probably from the coil driver gain. Rahul then swapped the LR and UR OSEMs and double checked the centering, and I ran another measurement 2026-03-25_1900, which looked about the same. Rahul then went and improved the balancing as best he could (the masses were pitching a bit) and I ran a final measurement 2026-03-25_2130.

Overall the Transfer Functions look ok but there's still room for improvement.

On Thursday Rahul balanced and set up OMA3 on the test stand. Unfortunately while manipulating OMA2 one of the bottom M2 stage wires broke, so we will have to replace it and remeasure it next week.

The OLV counts were as follows for OMA3:

UL: 27030 UR: 32100

LL: 27500 LR: 28900

The data/templates live in: /ligo/svncommon/SusSVN/sus/trunk/HXDS/X1/OMA3/SAGM1/Data

and the result pdfs are in: /ligo/svncommon/SusSVN/sus/trunk/HXDS/X1/OMA3/SAGM1/Results

This set of transfer functions, 2026-03-26_1900 also looks ok and similar to OMA2, see the comparison plot of OMA2 and OMA3. Both measurements shows some weirdness with LR that is not seen in an OSEM noise spectra that we're still looking into.

The next steps are to repair the bottom wire on OMA2, attach PSAMs cables, remeasure then fine tune both OMA2 and OMA3.

Tagging EPO for Corey for the pictures. I'm realizing I only have pictures of OMA3, I might comment with more photos on Monday of OMA2.

EPO, SUS

Images attached to this report

Non-image files attached to this report

2026-03-25_2130_X1SUSOMA2_M1_ALL_TFs.pdf

2026-03-25_1900_X1SUSOMA2_M1_ALL_TFs.pdf

2026-03-25_1730_X1SUSOMA2_M1_ALL_TFs.pdf

allhxdss_2026-03-25_X1-OMA2_HPDS_URLR-swap_ALL_TFs.pdf

2026-03-26_1900_X1SUSOMA3_M1_ALL_TFs.pdf

allhxdss_2026-03-26_X1-OMA2_OMA3_ALL_TFs.pdf

H1 SQZ - Comment to SQZ into IFO, Vented alignment not making it to HAM6 or SQZT7.

sheila.dwyer@ligo.org — Fri, 27 Mar 2026 13:36:38 -0700

Author: sheila.dwyer@ligo.org

Report ID: 89658

We need 4 things for the squeezer to operate:

Filter cavity green sensing (FCGS) reaching SQZT7
IR reflected off filter cavity making it back through VIP without clipping (IR on SQZT7)
IR flashes in filter cavity
Green flashes in filter cavity

Continuing from where Sophie and Camilla left off, I confirmed that the green I see on the FCES green camera is a single pass beam by misaligning both FC1 and FC2, they do not move this beam, and also confirmed that it's green by toggling the fiber input. I moved ZM3 to bring this to center on the camera, as we have not disturbed this FCES green path since O4. Then I did a raster on FC1 to get the IR seed reflected onto the SQZT7 IR PD (screenshot).

After moving FC2, I could see some green and IR on the FCES cameras. For IR, this is not the single pass beam but some reflections off FC1, for green we still see the single pass beam and a second beam coming close to the single pass beam, but it seems to have a very different beam size. screenshot. After this I went to SQZT7 and saw that the FCGS refl beam is making it to the table and aligned it onto the diode. Now we have 2.5 of the 4 things we need for the squeezer to work: green on SQZT7, IR on SQZT7, and the green single pass is heading towards FC2 well, which is part of what we need to get green flashes.

Sophie and I went to FCES. We tried moving FC2 to see what happened on the green transmission, we can see the beam reflected off FC2 leaks around the edge of the FC2 coating for some alignments, but that we can overlap them for some alignments, but do not see cavity flashes.

Camilla moved ZM3 back to the alignment where she found the green centered between the two places where it goes over the edge of the coating. This was a simlar situation in green.

In IR, we did see a single pass beam on the camera when Camilla steered ZM3. In 986 ZM3 is in the position where Camilla thinks IR is centered on FC2, you can see two green spots, and to the right and slightly below a very faint IR beam (I had to clean the laptop screen, turn the brigthness up to see it). In 988 ZM3 was at -506 P, -200 Y, the negative pitch clipping, you can see the brighter IR beam where it is transmitting through the uncoated part of FC2. 990 is ZM3 -324 P, -200 Y, going over the lower edge of the coating. 994 is with FC1 + FC2 in the aligned guardian state, moving FC2 until we saw something on the IR camera. 996 is for FC2 359 P, 28 Y, there was light on the IR diode, but the photo is dark.

Images attached to this report

LHO VE - HAM1 Both Doors are Removed

gerardo.moreno@ligo.org — Fri, 27 Mar 2026 13:20:11 -0700

Author: gerardo.moreno@ligo.org

Report ID: 89672

(Travis, Randy, Fil, Betsy, Marc, Jim, Gerardo)

Both doors for HAM1 are off, +Y and -Y.
- Y Door we had one of the O-rings get stuck to the door, used the tool to set the O-ring back into its groove without a problem. No further issues.
+ Y door, we took a peek at the O-rings and they looked suspiciously good all over, even with a small gap, but then out of the sudden one of the O-rings jumped out and dropped to the floor. So, the +Y door has the flange protectors over a single O-ring.

Purge air was turned up. A photo of the dew point is attached, this as measured this morning by Travis.

A big "thank you" for those that helped with the cleanroom moves.

Images attached to this report

H1 SEI - SEI status for vent Mar 27

jim.warner@ligo.org — Fri, 27 Mar 2026 13:13:50 -0700

Author: jim.warner@ligo.org

Report ID: 89673

As of right now, HAM1-2-3 and BSC 2 & 3 HEPI are locked, and after doors came off HAM1 ISI is also locked. HEPIs are all bypassed in the model (by setting ISO master gain to 0). HAM1 should just be left tripped for the work in that chamber, HAM 2 &3 and the BSCs should be left with damping loops engaged, unless there is a need for better alignment to the IFO.

OpsInfo

H1 ISC - Comment to BHSS / BHD work Mar 23: OMCB almost done, OMCA ready for alignment!

elenna.capote@ligo.org — Fri, 27 Mar 2026 11:05:54 -0700

Author: elenna.capote@ligo.org

Report ID: 89671

The naming convention listed above is incorrect. Please refer to alog 89669 for correct information.

H1 SUS - Comment to BHSS / BHD work Mar 18: Input alignment finished and OMCA in cradle!

elenna.capote@ligo.org — Fri, 27 Mar 2026 11:05:09 -0700

Author: elenna.capote@ligo.org

Report ID: 89670

The naming designation listed above for DCPDA/B is incorrect. Please refer to alog 89669 for correct information.

H1 ISC - DCPD designation for new OMCs on BHSS

elenna.capote@ligo.org — Fri, 27 Mar 2026 11:04:24 -0700

Author: elenna.capote@ligo.org

Report ID: 89669

Writing this alog to clarify some mistakes we have made regarding the naming of DCPDs. Jeff clarified to us on call this morning that the naming convention is A- photodiode on reflection, B- photodiode on transmission.

Therefore, here is the now corrected information about which high QE photodiodes are installed where, along with cabling and pin numbers:

OMCA (SN 103)

DCPD B (TRANS)
- DCPD: 1D-20
- Housing: SN 10
- cathode/anode/case wired to pins 1/2/6 of cable D2300118
DCPD A (REFL)
- DCPD: 1C-12
- Housing: SN 06
- cathode/anode/case wired to pins 4/5/9 of cable D2300118
PZT cable D2300120

OMCB (SN 105)

DCPD B (TRANS)
- DCPD: 1C-14
- Housing: SN 002
- cathode/anode/case wired to pins 4/5/9 of cable D2300119
DCPD A (REFL)
- DCPD: 1C-10
- Housing: SN 008
- cathode/anode/case wired to pins 1/2/6 of cable D2300119
PZT cable D2300121

CDS

H1 SYS - Comment to BSC2 Platform additional pieces installed

corey.gray@ligo.org — Fri, 27 Mar 2026 10:47:13 -0700

Author: corey.gray@ligo.org

Report ID: 89668

Tagging for EPO photos.

EPO

LHO VE - Fri CP1 Fill

david.barker@ligo.org — Fri, 27 Mar 2026 10:22:09 -0700

Author: david.barker@ligo.org

Report ID: 89667

Fri Mar 27 10:10:14 2026 INFO: Fill completed in 10min 10secs

Images attached to this report

H1 CDS - VACSTAT shows if it is running in a degraded state

david.barker@ligo.org — Fri, 27 Mar 2026 09:22:05 -0700

Author: david.barker@ligo.org

Report ID: 89666

I've added a "degraded state" indicator to the VACSTAT block on the CDS Overview MEDM (magenta oval in attachment). This circle is either the same light green as the block colour, or is a darker green to show at least one gauge has been disabled.

Currently we are running with HAM1 PT100 disabled in VACSTAT due to the vent.

The VACSTAT detailed MEDM (snippet in lower part of attachment) has a "NUM_GAUGES_DISABLED" line added, which turns RED if non-zero.

Images attached to this report

H1 SUS - Comment to Mar 26 BHSS Progress: Cables fixed, alignment started

elenna.capote@ligo.org — Fri, 27 Mar 2026 08:26:02 -0700

Author: elenna.capote@ligo.org

Report ID: 89664

I took some photos of the BHSS before we started work. Here are a few to show the progress so far. OMCA was uncovered before the photo, OMCB still covered by the butterdish. All the optics in the center are randomly attached. Platform is still locked down. Tagging EPO.

EPO

Images attached to this report

LHO FMCS - Comment to Return of the Kings

elenna.capote@ligo.org — Fri, 27 Mar 2026 08:21:46 -0700

Author: elenna.capote@ligo.org

Report ID: 89663

Yesterday (Mar 26), as we cleaned up after BHSS work, I looked around for more termites. I found only one in the corner of the lab near a circle of power cables, just underneath where we hang BNCs and other cables. It appeared to be dead. Not sure if it's new or I missed it the day before.

H1 CDS - Comment to OMC DCPD cable pins wiring confusion

keita.kawabe@ligo.org — Fri, 27 Mar 2026 08:19:15 -0700

Author: keita.kawabe@ligo.org

Report ID: 89662

For posterity, Ali etc. confirmed that the bias voltage is carried by pin 1 and 4 between the DCPD and the in-vac frontend: https://alog.ligo-la.caltech.edu/aLOG/index.php?callRep=80660

This means that the latest (fixed) version drawing for DCPD-D9M (https://dcc.ligo.org/D2300118-v2 and https://dcc.ligo.org/D2300119-v2) are correct, which is a good news!

This also means that the wiring diagram https://dcc.ligo.org/D2000592 is incorrect and the circuit diagram for the in-vac frontend https://dcc.ligo.org/D2200276 is incorrect or lacking information about the connection between the D9M feedthrough and the D9M connector on the board (e.g. the connection cable inside the box is not a usual cable but gender-changer type).

H1 General - OPS Friday Day shift start

ryan.crouch@ligo.org — Fri, 27 Mar 2026 07:52:25 -0700

Author: ryan.crouch@ligo.org

Report ID: 89661

TITLE: 03/27 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, 1mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.27 μm/s
QUICK SUMMARY:

HAM1 doors are coming off today +Y, -Y
- Later... set tables back up to lock JAC in air and work on REFL and POP paths

H1 SUS - Mar 26 BHSS Progress: Cables fixed, alignment started

elenna.capote@ligo.org — Thu, 26 Mar 2026 17:03:48 -0700

Author: elenna.capote@ligo.org

Report ID: 89659

Since yesterday, we have received an answer from Ali and Keita, that the determination is that the cathode and anode pins are in the correct location. There is a longer explanation about what's going on here and which diagrams are wrong, but I will leave that to them. Therefore, the only cable work that needs to be done is to adjust the pins on our "bad" cable, and then switch the DCPD cables between OMCA and OMCB.

Morning (no cable work):

Oli and I pulled the first contact that we left from yesterday. We just need one 50/50 45 deg AOI mirror for BHSS, and we were able to completely clean two of this type. More of these mirrors will be needed for the greater BHD layout, so Oli and I need to revisit the other three that still are not clean. For now, they are stored on the flow bench in clean single cases.

We went to begin the BHSS alignment, and found that no laser beam was coming out of the fiber. Some time between this alog, when Camilla and Oli aligned the beam into the fiber, and now, the beam was misaligned again. We think one of the mirrors to the fiber coupler was bumped. Correcting this took a little while. Oli had to leave, so Keita and I continued with the alignment. Luckily, our downstream alignment is still good- with the iris alignment template placed on the BHSS, we can see the beam comes down the center of both irises to OMCA.

Most of the beam reflects off the OMC, so Keita and I started turning up the power into the fiber. At some point, we turned up to 20 mW coming out of the fiber. We could see a faint beam transmit from the input coupler and make it to the output coupler. However, we still had a hard time seeing any beam make it to the DCPDs, probably because the power is still very low. We set up a beam block of the OMC REFL path for now, since it just goes right back off the suspension. At this point, we realized it's probably not a good idea to put so much power into the fiber, so we lowered the power again to have about 2 mW coming out of the fiber.

Afternoon (cable work):

Keita and I proceeded to fix the cables. We first checked which cables went to which pins:

Cable D2300119 (for OMCB): longer is on trans PD, goes to pins 4/5, shorter on refl PD, goes to pins 1/2

Cable D2300118 (for OMCA): longer is on trans PD, goes to pins 1/2, shorter is on refl PD, goes to pins 4/5

We confirmed that this is the correct wiring according to D2200276

Keita opened up cable D2300119, as this is the cable with incorrect wiring- case was wired to pin 2 and pin 5 instead of pin 6 and 9

We confirmed that the cathode is correctly wired to pins 1 and 4, so we only needed to swap 2/6 and 5/9.

Keita proceeded to switch the pins (this is a very short sentence to describe a long and painful process of removing various peek parts, poking pins through holes and resetting all the peek parts once finished)

Keita reclamped the lower part of the wires and we decided that we should clamp it very tight, as there were no gaps in the clamp on the other cable.

We then swapped the cables, as 118 was incorrectly placed on OMCB and 119 on OMCA. We decided to unscrew the PCB assembly on the back of each tombstone, and then swapped cables, paying attention to which cable went to trans and refl. Note: plugging the PCB assembly back into the DCPD pins is much much easier than inserting the DCPDs from the front.

We then decided to confirm the wiring was correct so we:

- checked that the case of each PD was wired to pins 6 and 9 (pass)

- checked the diode polarity was correct betweens pins1/2 and 4/5 (pass)

- checked that there were no shorts between any of the pins in the cable (failed for cable 119)

We found a short between pin 3 and 9 on cable 119. We removed the PCB assembly from the back of the DCPD tombstone and checked again, still a short. Keita then removed the lower part of the dsub9 assembly where the wires are clamped, and there was no longer a short between pin 3 and 9. We found one wire that was a bit stripped (see photo), but this was the wire for pin 4, so that didn't explain the problem. We were not able to find anything that could cause short between pin 3 and 9. We decided that maybe the pressure of the clamp caused this problem, so Keita reclamped the wires but less tightly, no more short. We checked one more time for case wiring, polarity, and shorts and all tests passed. Done!

CDS, ISC

Images attached to this report

LHO VE - HAM1 Vented and Annulus Vented

jordan.vanosky@ligo.org — Thu, 26 Mar 2026 16:52:33 -0700

Author: jordan.vanosky@ligo.org

Report ID: 89660

Travis, Jordan

HAM1 was vented today per M1300464 and E2300169, no pressure change in the corner during the venting. Dewpoint and particle counts collected prior to air admittance (-43C dew point).

Once the laser tables were moved away from the chamber, we vented the annulus system and all but 4 bolts were removed from both +Y and -Y doors in prep for door removal tomorrow.

Closing WP 13123

Images attached to this report

H1 General - OPS Thursday Day shift summary

ryan.crouch@ligo.org — Thu, 26 Mar 2026 16:32:58 -0700

Author: ryan.crouch@ligo.org

Report ID: 89654

TITLE: 03/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM1 was vented and the bolts have been broken, doors should come off tomorrow. BHSS work continues, and the LVEA is now in Upgrade Laser Safe.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:50	FAC	Nellie	LVEA	N	Tech clean	16:09
14:52	FAC	Kim	LVEA	N	Tech clean	16:09
15:07	FAC	Randy	LVEA	N	Checks around HAM1	15:35
15:54	ISC	Betsy	LVEA	N	Parts check/search	16:09
16:10	FAC	Nellie	MidY	N	Tech clean	16:52
16:11	FAC	Kim	MidX	N	Tech clean	17:28
16:28	VAC	Travis	LVEA	N	HAM1 purge air dewpoint particle checks	18:46
16:28	FAC	Randy	LVEA	N	Craning, checking out handrails	18:57
16:31	FAC	Tyler	LVEA	N	Join Randy	16:46
16:31	BHD	Elenna, Oli, Keita	Optics lab	LOCAL	BHSS work, first contacting optics Oli out 18:55	20:03
16:39	VAC	Jordan	LVEA	N	Join travis, HAM1 vent prep	18:46
16:40	FAC	Mitch	LVEA	N	Join Randy	17:25
16:52	FAC	Nellie	EndY	N	Drop off water	17:49
16:56	EE	Fil	LVEA	N	Cable termination, PSL racks	20:15
17:27	SUS	Jeff	LVEA	N	HAM3 check with CDS team	17:30
17:27	OPS	Betsy, Tony	LVEA	N	~~Key off SQZ laser, confirm we're in Upgrade Vent Safe, then move tables by HAM1~~	17:54
17:28	FAC	Kim	H2	N	Tech clean	17:39
18:18	EE	Tony, Marc	VAC prep/Optics lab	N	Cabling	19:20
18:26	FAC	Kim	LVEA	N	Tech clean	19:16
18:37	EE	Thomas	Vac prep lab	N	Make some invac cables	23:20
18:53	FAC	Tyler+contractors	MidY	N	Inspections, dpt of health+1more...	20:23
19:43	SQZ	Sheila	LVEA	LOCAL	SQZT7 local laser hazard for Green alignment	19:59
19:58	FAC	Randy	LVEA	N	Work on BSC2 platform	21:25
20:13	SQZ	Sheila, Sophie	FCES	Y	SQZT8, LOCAL hazard	21:51
20:29	EE	Marc, Tony	Optics lab	N	Cable testing	21:17
20:49	VAC	Jordan, Travis	LVEA	N	GV7, swap regulator	21:50
21:11	EE	Fil	LVEA	N	HAM3 cable terminations	Ongoing
21:19	BHD	Elenna, Keita	Optics lab	LOCAL	BHSS work	Ongoing
21:39	OPS	Betsy, Tony, Randy	LVEA	N	Turn off the SQZ laser and move the Tables by HAM1, for real this time, randy out 2215	22:37
22:05	EE	Marc	LVEA	N	Join Fil in cabling	Ongoing
22:08	PEM	RyanC	CER	N	Grab DM cable	22:15
22:37	VAC	Jordan, Tony, Travis	LVEA	N	Anulus ion pump, then break bolts on HAM1	Ongoing

17:00 UTC Jordan went over the VAC checklist and I confirmed the picomoters were off, the JAC PZT scan was disabled and its Driver offset was 0, and that the ISI and HEPI were in their safe states.

17:08 UTC HAM1 pressure starts to rise

17:11 UTC ISI HAM1 wd tripped

20:27 UTC Red alarm Dustmon6 by HAM6, 10.8k and 17.5k counts for the 0.3 and 0.5 um particles

21:58 UTC The SQZ laser was keyed off, The LVEA is now in Upgrade Laser Safe

22:00 UTC The tables by HAM1 were moved

23:05 UTC HAM2 ISI tripped from the HAM1 crew breaking the bolts, and the HAM1 sw watchdog

23:09 UTC RM1 and RM2 wd tripped, the HAM1 CPSs were glitching as well

23:31 UTC HEPI HAM1 watchdog tripped

H1 SQZ - Comment to SQZ into IFO, Vented alignment not making it to HAM6 or SQZT7.

camilla.compton@ligo.org — Thu, 26 Mar 2026 10:58:57 -0700

Author: camilla.compton@ligo.org

Report ID: 89657

Sophie, Camilla

This morning, starting from this vented slider alignments, I randomly moved ZM1 until we had IR and green light on the FCES PDs. I misaligned FC1 and FC2 to single pass light. Then I could move ZM3 in pitch from P,Y (-324,-200) to (-506, -200) to get max light on IR FCES PD. In both these positions, we get scattered light on the camera and light on both IR and green PDs. This makes me think the best position in pit h is in the middle of these, ZM3 (-415, 200). We tried to repeat this excise in yaw but only could get the one edge. Even after movingZM1 in YAW in both directions, I couldn't find the other side of the yaw clipped beam. Attached is the sliders when we thought we were centered in pitches and clipping the coating on one side in yaw.

Images attached to this report

H1 CDS - HAM1 PT100 disabled from VACSTAT for the duration of HAM1's vent

david.barker@ligo.org — Thu, 26 Mar 2026 10:35:28 -0700

Author: david.barker@ligo.org

Report ID: 89656

I reset a PT100 VACSTAT alarm at 10:12 and disabled HAM1.

LHO VE - Thu CP1 Fill

david.barker@ligo.org — Thu, 26 Mar 2026 10:31:43 -0700

Author: david.barker@ligo.org

Report ID: 89655

Thu Mar 26 10:11:54 2026 INFO: Fill completed in 11min 50secs

Images attached to this report

H1 SYS - BSC2 Platform additional pieces installed

betsy.weaver@ligo.org — Thu, 26 Mar 2026 10:16:36 -0700

Author: betsy.weaver@ligo.org

Report ID: 89653

On Monday, Randy, Jordan and the FAC team craned the HAM3 cleanroom over into the appropriate place for HAM3 entrance for installation planned next week. The cleanroom is now up against the BSC2 Platform. As well, Kim and Nellie have been cleaning the HAM3 cleanroom. On Tuesday, Randy craned into place and attached the new Installation Platform Sections G and F to the BSC2 platform. Handrails will be installed next. These platforms allow access from the eMod cleanroom to the BSC2 cross flow Dome cleanroom and platform, as well as provide added walking space between BSC2 and BSC3. They also form 2 sides of the BSC3 platform which will be needed in subsequent vents. Recall, this new LHO BSC2 Installation setup is part of the readiness review for install at https://dcc.ligo.org/E2400329-v1, and is part of a bigger plan to add sections around BSC3 and BSC1 to make a larger platform instead of moving them and encountering interferences other items like racks, trays and equipment.

Images attached to this report

H1 ISC - Comment to BHSS / BHD work Mar 23: OMCB almost done, OMCA ready for alignment!

corey.gray@ligo.org — Thu, 26 Mar 2026 08:46:41 -0700

Author: corey.gray@ligo.org

Report ID: 89652

Tagging For EPO photos.

EPO

H1 General - OPS Thursday day shift start

ryan.crouch@ligo.org — Thu, 26 Mar 2026 07:32:10 -0700

Author: ryan.crouch@ligo.org

Report ID: 89650

TITLE: 03/26 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: USEISM
Wind: 6mph Gusts, 4mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.55 μm/s
QUICK SUMMARY:

Zone5_I has been a little warm since the HAM1 CR has been turned on, its just off the plot but it looks stable
HAM1 vent work continues
More LVEA craning

LHO FMCS - Return of the Kings

oli.patane@ligo.org — Wed, 25 Mar 2026 17:18:20 -0700

Author: oli.patane@ligo.org

Report ID: 89648

"It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife"

- Jane Austen, opening line of Pride and Prejudice

But unfortunately for both us and them, sometimes those men are winged termites in the Optics Lab.

As Elenna and I were cleaning up our work in the back optics table this afternoon, we noticed a few winged termites, and ended up finding maybe almost 10 in total walking around on the floor in the back area of the optics lab near the wall mounted cabinets between the two cleanrooms. We got rid of them but couldn't find where they had come from. I'm wondering if they're maybe coming from an opening under one of those cabinets? Last year this happened but those came out from under the flow benches along the wall - not sure if this is part of that same colony that survived or a different colony.

AOS

Images attached to this report

H1 SUS - Mar 25 BHSS Progress

elenna.capote@ligo.org — Wed, 25 Mar 2026 17:07:58 -0700

Author: elenna.capote@ligo.org

Report ID: 89649

To summarize the ongoing issues from yesterday:

we determined that the cables (DCPD and PZT) attached to each OMC are mixed up
one cable has incorrect wiring, because the ground pins are not where they should be (pin 2 and 5 are ground instead of 6 and 9)
we're not sure if the polarity is correct on the diode

Keita and I have decided that swapping cables can possibly be done without removing the DCPDs. We're going to determine OMC A and OMC B based off of the PZT cable, and then swap the DCPD cables. We're waiting to hear the final verdict on the diode polarity to do pin adjustments and cable swapping.

In the meantime, Oli and I installed OMCB on the suspension and bolted it down using the OMC alignment template. We have placed the butterdishes over OMCA and B, but we haven't secured them yet with viton clamps while we continue to do work on the OMCs. The cables are only loosely clamped.

Next, Oli and I worked first contacting the remaining optics for BHSS- two HRs and one 50/50 splitter. The HRs were finished today, installed in their mounts, and placed randomly on the platform. The 50/50 splitter is still being FCed and should be ready in the morning. Once that optic is installed, we will proceed with the alignment of the OMCs and optics.

One vertical clamp is still missing from OMCB, but we should be able to install it once the helicoils and such arrive.

CDS, ISC

H1 SQZ - SQZ into IFO, Vented alignment not making it to HAM6 or SQZT7.

camilla.compton@ligo.org — Wed, 25 Mar 2026 16:40:43 -0700

Author: camilla.compton@ligo.org

Report ID: 89645

Sheila, Camilla.

We decided to pause on looking for the FC alignment and look at SQZ alignment into the IFO. To check our irises and possibly look for scattering shelves.

Locked SEED_DITHER with 75mW into fiber. Moved ZM3 to get OPO_IR PD up to max 0.9mW. Opened BeamDiv and after aligning SRM, mis-aligning SR2, could see beams on AS_A,B and C. AS_A and B had a similar size ~60 to reported before (e.g. 86965), but there was less power on AS_C: 4e-4 rather than the previous 7e-4.

We used Ryan's DRMI time from 89573 to put OM1, OM2 and SRM back. The with the SQZ SEED injected, we tried to use SQZ centering loops to center on AS_A and AS_B, this didn't work quite as expected. ZM4 kept saturating although these loops had worked Janaury 19th, before moves were done on the VOPO to help with clipping e.g. 88966.

Then went back to alignment on Jan 31st with 88976 with ZM1,2,3, 4,5,6 FC1. And took OM1,2,SRM to the January 19th positions. However here we saw no light on SQZT7 OPO IR PD, HAM7 WFs or in HAM6 on the AS_A,B,C diodes. This was done at 23:10 UTC. Comparisons of osems attached. The sliders to get these osems values are fairly different, see attached, so I also tried going to these slider values, that gave me some light on SQZT7 IR PD, HAM7 WFS and FCES with SEED injected, see attached. HAM6 AS diodes saw nothing.

Images attached to this report

H1 SEI - Comment to Hepi Pump Trends (Monthly)

jim.warner@ligo.org — Wed, 25 Mar 2026 16:40:38 -0700

Author: jim.warner@ligo.org

Report ID: 89647

FRS ticket: https://services1.ligo-la.caltech.edu/FRS/show_bug.cgi?id=37356

H1 SEI - Comment to Hepi Pump Trends (Monthly)

jim.warner@ligo.org — Wed, 25 Mar 2026 16:35:09 -0700

Author: jim.warner@ligo.org

Report ID: 89646

I have looked at the EX pressures a bit and I suspect that one of the pressure sensors on the EX manifold has gone bad.

On the attached trend, the top 2 traces are PRESS1 and PRESS2, bottom 2 traces are the same pressures at EY. EX PRESS1 starts seeing bigger peak to peak signal starting about 50 days ago, but PRESS2 doesn't see this increase in pressure noise. Second attach image is a zoomed in trend of the same channels. EX PRESS1 seems to have some kind of 1hz oscillation. PRESS2 might be seeing some of this same signal, but not to the same extent. The supply pressure to the VEA at EX definitely doesn't see this 1hz signal, so I think it's either not real or it's being filtered out at the manifold.

I have yet to go down to EX and test this, but I will try to do so this week.

Images attached to this report

H1 General - OPS Wednesday Day shift summary

ryan.crouch@ligo.org — Wed, 25 Mar 2026 16:30:55 -0700

Author: ryan.crouch@ligo.org

Report ID: 89639

TITLE: 03/25 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: GV7 is still broken and will not hard close, HAM1 vent prep work, the PSL incursion was completed, and the BHSS work continues in the Optics lab.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:15	FAC	Kim, Nellie	LVEA	N	Tech clean	14:54
15:05	VAC	Gerardo, Jordan	LVEA HAM1	N	Open ION pump	15:09
15:08	FAC	Randy	LVEA WBay	N	Craning Test stand, not over the tube	16:12
15:19	SEI	Jeff	Optics lab	LOCAL	Turn off laser	15:27
15:28	SEI	Camilla, Jeff	Optics lab	N	Parts search / checks Camilla out 15:45	15:48
15:35	SEI	Jeff, Camilla	LVEA	N	Grab power meter	15:45
16:02	TCS	Sophie	Prep lab	N	CHETA work	16:19
16:08	EE	Marc, Fil	LVEA H1,2	N	Cabling fiber, SUS to SAFE	18:58
16:19		Betsy	CER/Clean storage, Optics lab	N	Put away garb and other stuff	16:37
16:20	BHD	Elenna, Keita	Optics lab	N	BHD/BHSS work	17:26
16:22	SQZ	Camilla	LVEA, SQZT7	LOCAL/HEIGHT	SQZT7 table alignment, bringing glasses for Fil, Marc	16:33
16:33	PSL/SPI	Jeff, Jason, Sina	PSL, Racks, PSL encl	N / LOCAL	SPI fiber work, Jason out 18:30	18:46
16:39	FAC	Kim	LVEA	N	Tech clean	18:09
16:46	FAC	Randy	LVEA WBay	N	Test stand work	17:39
16:48	ISC	Ibrahim	CER/ Clean storage	N	Inventory C3 covers	19:21
16:48	SQZ	Camilla, Sheila	LVEA	LOCAL	SQZT7 work, LOCAL and HEIGHT LASER HAZARD	17:04
16:59	ISC	Jenne	LVEA	N	Talk to Camilla/Sheila	17:02
17:06	BHD	Oli	Optics lab	N	BHD/BHSS work	17:40
17:17	ISC	Jennie	Optics lab ->LVEA	N	Check for parts, put away in LVEA	17:35
18:23	SPI	Bram	LVEA	N	Check with Jeff out with Jeff	19:11
18:35	VAC	Travis	Site	N	VAC property inventory	21:53
18:37	VAC	Gerardo	LVEA	N	Turn on purge air for HAM1	19:13
18:39	OPS	Betsy, Tony	LVEA	N	Double checking LASER SAFE status	19:11
19:17	OPS	Tony	LVEA	N	Grab paper and table keys	19:22
19:29	FAC	Randy, Jim	LVEA	N	Turn on HAM1 CR and work on the test stand Jim out 20:20	20:27
19:34	ICS	Camilla, Calum	Optics lab	N	Check on parts	19:52
20:09	SEI	Jeff, Bram, Sina	Optics lab	LOCAL	SPI work	Ongoing
20:18	TCS	Sophie	Prep lab	N	CHETA work	21:03
20:21	SUS	Oli	LVEA	N	Take picture of a rack	20:25
20:32	BHD	Elenna	Optics lab	LOCAL	BHSS work	Ongoing
20:34	PEM	RyanC	CER	N	Swap dm comms cables	20:41
20:37	SUS	Oli	Optics Lab	LOCAL	Working BHSS system	Ongoing
20:40	SQZ	Sheila	SQZT7	N	Checking for people working at height to transition.	21:02
20:41	EE	Fill	CER	n	Grounding cables	Ongoing
20:51	VAC	Gerardo	LVEA	N	Take off turbopump	21:02
21:01	EE	Betsy, Marc, Tony	Vac Prep	N	Cable testing	Ongoing
21:49	OPS	Ibrahim	CER / Clean storage	N	C3 cloth covers checks	22:18
22:35		Calum	Vac Prep lab	N	Talk to Betsy	23:20
22:58	VAC	Jordan	LVEA	N	Grab parts by HAM1	23:03

19:19 UTC Tony keyed off TCSY

H1 SUS - Comment to PR3 Oplev Whitening Chassis Moved up in SUS-R2

oli.patane@ligo.org — Wed, 25 Mar 2026 13:33:09 -0700

Author: oli.patane@ligo.org

Report ID: 89644

Adding more photos showing the whole rack so I can accurately update the cable wiring diagram

Images attached to this report

H1 SUS - PR3 Oplev Whitening Chassis Moved up in SUS-R2

jeffrey.kissel@ligo.org — Wed, 25 Mar 2026 13:02:51 -0700

Author: jeffrey.kissel@ligo.org

Report ID: 89643

J. Kissel, M. Pirello While in SUS-R2 and thinking SPI, and looking at the proposed rack layout from G2401479, and accounting for all the SUS (BBSS, LO1, LO2) that's incoming for O5 -- I found that SPI can have a bit more space if we just move the SUS-PR3 optical lever whitening chassis up 5 U-heights from "32" to "27." I put the u-height in quotes because this is an old style rack with the u-heights labeled from top down, rather than the bottom up per industry convention. I would have and could have gone higher, but the 27 slot already had mounting clips in it, so I went there. We can go as high as "25" if need be in the future. Pics of before vs. after are attached.AOS, SPI

Images attached to this report

H1 SPI - SPI Fiber Patch Cable from PSL to SUS-R2 Installed; Verified Excellent Transmission

jeffrey.kissel@ligo.org — Wed, 25 Mar 2026 12:56:03 -0700

Author: jeffrey.kissel@ligo.org

Report ID: 89642

F. Clara, J. Kissel, S. Koehlenbeck, J. Oberling, M. Pirello D2400110 Today we picked up where we left off with the install of SPI into H1. Where we last left things, we'd installed a new SPI pick-off of ALS/SQZ beam in Apr 2025 (see ECR E2400083 and results in LHO aLOGs 83989, 83996, 83978). Back then, we had ended the work with the input to the fiber collimator within the PSL dumped. With Jason and Sina in the PSL, we confirmed that the SPI path was still blocked. However, we also realized/remembered/confirmed that the entire ALS/SQZ/SPI path had 25% less power -- We've been running the PSL at lower power allocation downstream of the PMC since Sep 2025 to prevent issues we'd found with the currently installed EOM after a power outage triggered a dust monitor to spew out dust into the PSL (see that saga in e.g. LHO:87109 LHO:86966). They found the power at the SPI pick-off was 140 [mW] instead of the 188 [mW] we left in Apr 2025 (see LHO:83996). (Using labels in the half-up-to-date drawing D1300348) Jason and Sina rotated ALS-HWP2 upstream of ALSPBS01 to restore the nominal 50 [mW] into the ALS/SQZ pick-off and ~200 [mW] (190 [mW] measured). This means there's ~50 [mW] less out to ALS / ISCT1 than before today. Then with the SPI pickoff still dumped, we installed a 30 [m] patch cord*** from the PSL optical table, out the mouse hole between the +X wall of the PSL enclosure and HAM1, then up running along the upper racks to waterfall down at SUS-H2. The fiber sits within the typical orange tubing. Per D2400110, this is SPI_PSL_001, and it's labeled as such on both ends. After install, I connected the SUS-R2 end to a Thorlabs S121C power meter with S120-APC2 fiber adapter. With this installed (making the system laser safe at SUS-R2 end), Jason/Sina unblocked the SPI pickoff input. With 190 [mW] in, we measure 187 [mW] out on the other end. 98% transmission, pretty excellent. Almost unbelievably excellent but we weren't rigorous with our uncertainty and systematics. Happy with this result, we then blocked the SPI path again, and re-capped the SUS-R2 end for final dressing in the racks. We'll unblock again when we're read to connect it to the Laser Prep Chassis. ***Patch cord details: Manufacturer DIAMOND DIAMOND Part Number: ENS/1094388 Customer Part Number: 9711228 Patchcord SM L=30 PM 2xFC 2mm APC (i.e. 2mm narrow key FC/APC on both ends) tran 6,6/125/245 PAND 980nm CDS, PSL

H1 CDS - SPI and JAC Cable Work

filiberto.clara@ligo.org — Wed, 25 Mar 2026 12:49:10 -0700

Author: filiberto.clara@ligo.org

Report ID: 89641

WP 13105
WP 13113

During the last two days CDS EE has completed the following:

SPI Optical Fiber pulled from the PSL enclosure to SUS-R2
Heliax cable pulled from ISC-C3 to SUS-R2, part of SPI
Two Heliax cables pulled from ISC-C4 to ISC-R2, part of JAC
Cabling disconnected to IOT1 and ISCT1

This completes dirty work over HAM1 and HAM2. In the next two weeks, will close out work in SUS-R2 before HAM3 is vented.

List of items needed for SUS-R2:

Install power supplies in CER Mezzanine
Terminate power cables and install junction box
Terminate Heliax cable
Test and install two SAT Amp Chassis
Installation of DC sequencer
Install QOSEM Sat Amp
Pull cabling from SUS-R2 to HAM3
Installation of SPI electronics

F. Clara, J. Kissel, J. Oberling, M. Pirello, T. Sanchez, and R. Thompson

ISC, SPI, SUS

H1 AOS - CHETA Updates - QCL unit failure

sophie.muusse@ligo.org — Wed, 25 Mar 2026 12:10:55 -0700

Author: sophie.muusse@ligo.org

Report ID: 89638

S. Muusse, C. Compton

0920 QCL unit failure summary:

We were beam profiling the laser and I had the profiler ~8” from the laser head, with a steering mirror to steer onto the scanner. Laser was at 1A. I blocked and unblocked the beam but as it was unblocked there was a beep and there laser controller turned off with message “LD output voltage protection was tripped”.

I then turned controller off and back on again with power down to 0.5A and it would not turn on.

Camilla then came into the lab, we turned off and unplugged controller. It was turned on again, would not turn on. Remembering LLO's issues, on the Temperature Protection screen we eased the +-5 deg requirement to +-6. Laser then appeared to turn on with “laser current reading 0.500 A” and “laser voltage reading 10.440V”, temperature 25deg. However no beam was coming from the laser.

We then turned off and on laser. Again appeared on but no beam, slowly turned up current from 0.5A towards 1A, at 0.84A controller beeped with “LD output voltage protection was tripped” message again.

QCL Unit q-parameter dependance on laser temperature:

Unit failure happened while profiling the laser to check if the q-parameter of the QCL has a temperature dependence. This profiling was done largely at a 23mm offset with one point near the waist. However, there was not an opportunity to take more measurements around the waist in this new data because of the failure which may cause some inaccuracies in the fitted q. I used a non linear fit where M2=1. This is consistent with the fitting by Matt. His measurements were completed at 20 deg but after advisement from thorlabs we have increased operating temperature to 25 deg.

Temperate [deg] /date	Horizontal [mm]	Vertical [mm]
20 / 2025-09	- 174 + 67i	- 209 + 56i
25 / 2026-03-24	-129 ± 6 + 71 ± 2i	-155 ± 6 + 59 ± 2i

With the new q factors there is slightly better agreement between the fitted q-parameter for L2 and the model.

Vertical

Measurement/model	w0 [ µm]	z [mm]	w at ITM [mm]
Fit from data:	978.9±22.7	-1063.1±33.8	50.09
Fintrace q: - 209 + 56i (old)	857.11	-500.64	61.38
Fintrace q: -155 + 59i	992.56	671.38	54.083

Horizontal

Measurement/model	w0 [ µm]	z [mm]	w at ITM [mm]
Fit from data	1280.3+/-54.9	-1813.3±83.5	38.01
Fintrace q:- 174 + 67i (old)	979.42	-653.71	54.38
Fintrace q: -129 + 71i	1127.3	-866	47.939

Images attached to this report

H1 SQZ - Comment to SQZ FC Alignment Tuesday

camilla.compton@ligo.org — Wed, 25 Mar 2026 12:09:59 -0700

Author: camilla.compton@ligo.org

Report ID: 89637

Sheila, Jenne, Camilla

Today Sheila and I went onto SQZT7 to try to align the FC green REFL beam onto the diode so we could lock the FC in green. Could see on the periscope that the FCGS REFL beam was clipped. Sheila remembers it was not clipped last week before she pico'ed the green beam so we Jenne and I went back to where we had good IR and green FC flashes and undid Friday's 89596 pico-ing. This made the green yaw beam look much worse and flashes decrease as expected.

I then went back to here we had green FC flashes with IR on SQZT7 and repeated when we did yesterday but with YAW, moving ZM1 and bringing flashes back with ZM2 in the direction to de crease the amount ZM3 needed to move to get light back on SQZT7. I did completely loose the FC IR beam doing this though in going to the green FC flashes with IR on SQZT7 place.

Images attached to this report

LHO VE - Wed CP1 Fill

david.barker@ligo.org — Wed, 25 Mar 2026 11:05:48 -0700

Author: david.barker@ligo.org

Report ID: 89636

Wed Mar 25 10:11:55 2026 INFO: Fill completed in 11min 52secs

Images attached to this report

H1 CDS - Comment to OMC DCPD cable pins wiring confusion

oli.patane@ligo.org — Wed, 25 Mar 2026 10:55:23 -0700

Author: oli.patane@ligo.org

Report ID: 89635

Keita, Elenna, and I just went in and tested the direction the current is flowing for the DCPD cables (D2300118 and D2300119).

D2300118 (SN S2500546)
Current direction:
- Pin 2 -> 1
- Pin 5 -> 4

D2300119 (SN S2500548)
Current direction:
- Pin 6 -> 1
- Pin 9 -> 4

We verified that there was no current flow when probes were swapped

H1 SQZ - SQZ FC Alignment Tuesday

camilla.compton@ligo.org — Wed, 25 Mar 2026 09:09:38 -0700

Author: camilla.compton@ligo.org

Report ID: 89629

Sheila, Camilla

While we had good green (20) and IR (1) FC flashes, we had to move 100urad in ZM3 positive PIT to get any light on SQZT7 OPO IR PD, see -2h30 on screenshot.

We then walked ZM1 and ZM2 both in negative PIT (which seems a bit weird but worked) until we only had to move ZM3 13urad to get light on SQZT7. However in doing this move, we lost the majority of IR light and some green light, see t-cursor #1 of screenshot. I injected the SEED beam at this point and the IR FC camera looked again like a strange cross or swallow bird. I hoped to move ZM3, FC1 and FC2 to bring back IR light but wasn't able to.

I was able to get good green flashes simultaneously with SQAT7 IR light but then I had no IR FC light, see t-cursor #3 of screenshot, 22:35UTC.

Vicky reminded us of 2022 when we had to pico to get FC green/IR co-resonance: 66017, 66281

Images attached to this report

H1 General - OPS Wednesday Day shift start

ryan.crouch@ligo.org — Wed, 25 Mar 2026 07:30:10 -0700

Author: ryan.crouch@ligo.org

Report ID: 89634

TITLE: 03/25 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: 5mph Gusts, 2mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.23 μm/s
QUICK SUMMARY:

The JAC and IMC were held DOWN/OFFLINE overnight (IOT1 is disconnected)
Test stand craning, cabling, SPI, and BHSS work continues
The CEBEX workshop continues in the front MPR

H1 IOO - Comment to JAC flashing

jenne.driggers@ligo.org — Tue, 24 Mar 2026 19:41:12 -0700

Author: jenne.driggers@ligo.org

Report ID: 89633

Betsy reminded me that the IOT table was unplugged in prep for venting, and that's why JAC was failing to lock.

LHO VE - Comment to GV7 Work Update

gerardo.moreno@ligo.org — Tue, 24 Mar 2026 18:14:37 -0700

Author: gerardo.moreno@ligo.org

Report ID: 89632

(Travis S., Jordan V., Richard M., Gerardo M.)

We bypassed the gate valve instrument air regulator and feed bottled air to the gate valve actuation system directly. We continued where we left off, and just continued to apply pressure to the system in an attempt to "hard close" the gate valve, and a second approach was to open the gate valve and close it again.

We continued to apply pressure were we left off yesterday, we reached and sat at 55 psi for 30 minutes, valve remained "soft closed". We decided to try a different approach since we were loosing air due to leak in gate valve actuation system.
We opened GV7 back up, then closed it again, we then applied more pressure to the system, this time we reached 60 psi, and left it there until air ran out, about 20 minutes, no change noted or heard on the gate valve.

Leaky sound noted, we did noticed that when we are on the "close" setting, there is lots of hissing sound coming from one of the "relief ports" at the solenoid valve, but when we are on the "open" setting, there is no hissing at the solenoid valve. And if there is is very small.

Non-image files attached to this report

20260324-GV7_AirLeak.mov

H1 IOO - Comment to JAC flashing

jenne.driggers@ligo.org — Tue, 24 Mar 2026 17:29:25 -0700

Author: jenne.driggers@ligo.org

Report ID: 89631

After talking to Keita, I set the JAC to Down.

H1 IOO - JAC flashing

jenne.driggers@ligo.org — Tue, 24 Mar 2026 17:26:12 -0700

Author: jenne.driggers@ligo.org

Report ID: 89630

The JAC seems to be failing to lock. I'm not sure why, but since it's just scanning I assume it's fine for the night. But, if someone with more JAC experience thinks it's useful to log in and set it to DOWN for the night, that would be good.

LHO General - Tues DAY Ops Summary

corey.gray@ligo.org — Tue, 24 Mar 2026 16:34:28 -0700

Author: corey.gray@ligo.org

Report ID: 89612

TITLE: 03/24 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

Hard closing GV7 continues (no luck today). New platform craned into place between BSC2+3. Filter Cavity gate valves opened for more Squeezer alignment. Lots of cable/fibers pulled in the LVEA. Optics Lab was busy with Team SPI & Team BHSS work (as well as Team CHETA lab next door).

LOG:

1442 LVEA technical cleaning begins (kim, nellie)
- 1550-1630 break
- 1630 back out to LVEA (kim,nellie)
  - 1712 nellie out
  - 1749-1841 kim out, and then back in the lvea one more time from 1841-1916
1457-1507 Closing Filter Cavity GVs (total of 6) [jodan]
1503 Untripping Hardware Watchdog (jonathan)
- did not work but couldn't reset
- fil check wiring?
- may have to boot
- it got booted during Dec power outtage
1508 Prepping for "furniture moves" & craning: main work today is a new platform between BSC2 & 3 probably this morning (randy)
- 1526-1552 Mitch joining
1525-1727 Norco LN2 @MX CP6
1540 SQZ bay clean-up & TCSy laser power ON (camilla)
1542 Getting big cable spool ready for cable pulling (fil, tony, randy)
1605 Cable pulling begins! (fil, tony, marc)
- HAM1 HAM2 taken to DAMPED
- 1842--break for lunch, most cables run. Dressing cables remains (marc)
1611-1742 Locking HEPIs: HAM3, BSC2, BSC3 (jim)
- Above chambers taken to DAMPED
- Betsy asked for HAM1+2 to be added as well!
- (If they are tripped, leave them that way since there is lots of activity out there anyway.)
1612-1632 PSL anteroom prep to cover hardware for HEPA fan replacement (jason)
1629-1858 BSC2/3 platform (randy.mitch)
- This concludes craning WITH a load. Platform still rigged to the crane as Randy gets ready to secure it in place. But now craning loads over the Filter Cavity Beam Tube is technically complete (Randy notifying Betsy)
1704-1728 Picking up battery charger part for scissor lift (chris)
1737-1920 Norco LN2 truck delivering to EX's CP8
1745-1929 BHSS laser hazard alignment in optics lab (elenna, oli)
1752-1836 ergo arm tests (ibrahim, ryanC)
1750-1811 Jenne tour in CR
- 1811-1904 Moving to LVEA with small group
1811-1828 Maggie Mt. Adams Middle School (8th grade) tour
1853-1912 transition FCES to safe (camilla)
1907-1920 Filter Cavity mini-gate valves closing (gerardo)
1931 Finish off cable pulling (fil, marc)
- Switching to SPI optical fiber
- disconnecting some cables from HAM1/2 in-air tables
1941-2135 Secure platform (& then disconnect off crane) [randy]
2003-2014 Quick cable check for BHSS (oli)
2005 Gathering up gas containers in lvea for GV7 (travis)
- 2103 Joining travis for GV7 work (gerardo)
- 2225-2259 joining VAC crew at GV7 (jordan)
- 2306 no luck on GV7's hard close (travis,gerardo)
2034-2047 Packaging up the ERGO Arm after earlier tests (ibrahim)
2037 SPI layout work (jeff,sina, bram)
2043 Optics Lab and LVEA walkabout (betsy)
2056 Tracter w/ Loader & back hoe heading to CEBEX site
2118-2239 Inventory C3 covers in Cleaning Room (ibrahim)
2128-2229 BHSS work (elenna,oli)
2210 CHETA table work (sophie)
- 2234 camilla joining

H1 CDS - Comment to OMC DCPD cable pins wiring confusion

elenna.capote@ligo.org — Tue, 24 Mar 2026 15:44:35 -0700

Author: elenna.capote@ligo.org

Report ID: 89628

Here is a further update. This is based on conversations with Keita and Betsy, and emails to and from CIT and LLO.

At first, it appears one issue here is that I have made a mistake OMC placement, as D2200276 indicates that OMCB should have the DCPD cable labeled D2300119 (and PZT cable D2300121), and OMCA should have D2300118 (and PZT cable D2300120), and I installed them opposite according to the DCPD cables. This doesn't account for the wiring issue; it would only make a cable length difference.

Oli and I went into the lab to swap around OMCA and OMCB, and realized that one OMC has the DCPD cable for A (D2300118) and PZT cable for B (D2300121) and vice versa. So it's not clear which is which.

Keita has further pointed out that this wiring issue with the grounding pins could indicate cathode and anode are swapped, which means that the diode will be forward biased, which is a much bigger issue.

Therefore, we're pausing on all BHSS work for now until we can figure out how to resolve these problems.

LLO has not checked their wiring, but Oli and I did note that they paid attention to the OMC labeling since they knew the cable lengths would be different.

When our OMCs were shipped to us, the ameristat wrapping had OMC A and OMC B labels, but once we took the wrapping off, there was no indication of A and B on the boxes.

H1 CDS - Comment to OMC DCPD cable pins wiring confusion

keita.kawabe@ligo.org — Tue, 24 Mar 2026 15:36:06 -0700

Author: keita.kawabe@ligo.org

Report ID: 89627

Two problems with the drawings.

1. Case grounding.

As for cable and connection drawings, D2200276-v4 wiring diagram specifies that pin1-2 and pin4-5 twisted pairs carry the photocurrent, pin1 and pin4 being cathode, and case grounds are routed to pin6 and pin9, between DCPDs and the in-vac DCPD frontend. See the 1st attachment.

D2300118 DCPD to DB9M cable doesn't agree with the wiring diagram, it routs the case grounds to pin 2 and pin 5. See the 2nd attachment.

D1300369 DB9F-DB9F cable drawing agrees with the wiring diagram in that pin1-2 and pin4-5 are twisted pairs.

D2000592-v3 in-vac DCPD frontend seems to be compatible with the wiring diagram in that it routs the pin6 and 9 to the ground.

So, D2300118 DCPD to DB9M cable drawing is singularly incompatible with others.

Below is a summary table of the above together with reality check of the DCPD-DB9m cable. It seems that there's no way OMCA cable works. Anode/Cathode check wasn't performed (yet).

	pin1	pin2	pin6	pin4	pin5	pin9
D2200276-v4 wiring diagram	Cathode1	Anode1	Case1	Cathode2	Anode2	Case2
D2300118 DCPD to DB9M cable	Cathode1	Case1	Anode1	Cathode2	Case2	Anode2
D1300369 DB9F-DB9F cable (pass through)	compatible with the wiring diagram in that pin1-2 and pin4-5 are twisted pairs.
D2000592-v3 in-vac DCPD frontend (outside of the enclosure feedthrough)	Internally routed to PD1 pin1	Internally routed to PD1 pin2	Internally routed to GND	Internally routed to PD2 pin1	Internally routed to PD2 pin2	Internally routed to GND
OMCA reality	Case	?	?	Case	?	?
OMCB reality	?	?	Case	?	?	Case

2. Polarity of the diode seems to be wrong.

Assuming that the wiring diagram and the in-vac DCPD frontend circuit diagram are both correct, cathode1 and anode1 are routed to "PD1 pin1" and "PD1 pin2" while cathode2 and anode2 are routed to "PD2 pin1" and "PD2 pin2". So, pin1 and pin2 inside the frontend chassis are cathode and anode. Again look at the first attachment.

However, whey you look at the circuit diagram of the frontend (3rd attachment), pin2 is connected to the positive bias and pin1 is grounded (via the huge inductor). This means that the PD is forward-biased and will be unusable. Is this only in the drawings?

What to do.

First thing is to check the diode polarity in reality, i.e. if cathode is routed to pin 1 and 4 (which I expect) or to pin 2 and 5 (which I don't expect). In parallel, check with Ali/Dean that my assessment of the polarity makes sense or not.

Depending on the results of the polarity investigation, we'll determine which cable needs to be reterminated how. If we're lucky we'll just reterminate only one cable, but if the PD polarity is indeed wrong we'll have to reterminate all cables.

Images attached to this report

H1 AOS - Comment to FARO Survey of WBCS3 and Partial WBSC2 Support Tube Ends

jason.oberling@ligo.org — Tue, 24 Mar 2026 14:32:17 -0700

Author: jason.oberling@ligo.org

Report ID: 89626

I've attached the same centerline picture of the WBSC3 support tubes as I used for the WBSC2 support tubes in alog 89619 (2nd attachment in that alog). This shows that the support tubes are shifted in the +Y direction, with the +X support tube shifted 1.381mm further +Y than the -X support tube is. This again implies a yaw in addition to the +Y shift. As I did for WBSC2, averaging out the shift gives a +Y shift of ~1.7mm and a CCW yaw of ~824 µrad.

Again, this is not indicative of any misaligment in ITMx, as we moved HEPI to place the optic where it needed to be, and the support tube ends ended up where they ended up.

Images attached to this report

H1 AOS - WBSC2 Support Tube Ends Surveyed with FARO

jason.oberling@ligo.org — Tue, 24 Mar 2026 14:20:14 -0700

Author: jason.oberling@ligo.org

Report ID: 89619

J. Oberling, R. Crouch

In talking with Calum about the upcoming pre-deintall BS measurements, I realized that in the middle of JAC install I completely forgot to write an alog about the WBSC2 support tube FARO survey Ryan and I did at the beginning of February. So, here it is.

Following the same procedure we used to survey the support tubes for WBSC3 and the +X ends of WBSC2 (alog 88620), we surveyed the -X WBSC2 support tube ends. The results are shown in the 3 attachments; the first 2 are in the LHO Global Coordinate system and are the images I will be discussing. The 3rd attachment contains all info from the first 2, but in the Corner Station building Local Coordinate system (included for completeness; for more on LIGO coordinate systems, see T0900340). The first attachment shows the surveyed locations of the support tube ends, while the 2nd shows information regarding the midpoint location of the support tubes and their angles w.r.t. the IFO axes (the line shown represents the centerline of the support tube created from one end point to the other; the Nominal column (Nom) comes directly from the CAD model, while the Measured column (Meas) is our measured data. Some interesting things to note here:

Both support tubes are shifted in the -X direction, with the +Y support tube shifted 2.3mm more than the -Y support tube. This is seen in the Midpoint X row in the centerlines image (2nd attachment).
- This implies a CCW yaw of the WBSC2 cartridge assembly, in addition to the -X position shift
- Averaging out the shift, this implies a -2.6 mm shift in the X axis position, and a 1.36 mrad CCW yaw
My expectation was to find the support tubes too low in their Z axis position by ~2.5mm, but that is clearly not the case.
- The BS SUS is the same length as the QUAD SUSs, but the BS sits lower in the coordinate system than the QUADs do (-82.9mm vs -80.0mm); this difference was to be made up with HEPI (i.e. shifting the support tubes lower), since physically making the BS SUS longer isn't exactly practical
- The support tube end survey in the 1st attachment show the ends are not lower by ~2.5mm as expected, but rather fairly close to the nominal Z axis position
No real comments re: Y axis position, this looks good

Now keep in mind that the support tube locations may not be indicative of a misalignment of the BS optic itself. When we installed this we only cared about putting the BS where it needed to be, and HEPI (and by extension the support tube ends) was wherever it (they) needed to be to support that. We will be taking measurements of the BS SUS cage and the optic itself once the corner is vented (likely to be one of the 1st activities after the vent), and we'll know more about the location of the BS optic once we have done so.

Images attached to this report

LHO VE - GV7 Work Update

gerardo.moreno@ligo.org — Tue, 24 Mar 2026 13:41:05 -0700

Author: gerardo.moreno@ligo.org

Report ID: 89625

(Travis S., Jordan V., Richard M., Gerardo M.)

Last Friday we tried to "hard close" GV7, but we only achieved a "soft close" status. After looking at the system that uses instrument air at the gate valve, we did noticed that the solenoid valve to "open" and "close" the gate valve was "leaking" air, lots of instrument air, to fix the air leak we decided to replace the solenoid valve with a new one.
Then when it was time to "hard close" GV7, its pressure regulator broke, we were not able to open the regulator. We ordered a couple of new regulators and should be here on Wednesday. Meanwhile we are going to "hard close" the gate valve using a bottle of nitrogen.
Attached is a photo of the broken regulator, yes the knob is off, but the metal piece within is free floating and not able to do its job.

Images attached to this report

H1 CDS - Comment to Recovering SWWD and HWWD trips after Mon 21:45 PDT earthquake

david.barker@ligo.org — Tue, 24 Mar 2026 13:21:44 -0700

Author: david.barker@ligo.org

Report ID: 89624

WP13115 to possibly prevent future HWWD trips by shortening time-to-trip of SWWD to 15 minutes.

H1 CDS - Comment to Recovering SWWD and HWWD trips after Mon 21:45 PDT earthquake

david.barker@ligo.org — Tue, 24 Mar 2026 13:17:12 -0700

Author: david.barker@ligo.org

Report ID: 89623

Summary of our 3 HWWD trips has been submitted to the DCC T2600092

As was done at the end station test masses, we need to reduce the time-to-trip for the SUS SWWD from 20 minutes to 15 minutes.

H1 CDS - Comment to Recovering SWWD and HWWD trips after Mon 21:45 PDT earthquake

david.barker@ligo.org — Tue, 24 Mar 2026 13:14:40 -0700

Author: david.barker@ligo.org

Report ID: 89622

Attached plot shows the suspension started recovery when the SWWD SUS tripped at 22:19:52 and 41 seconds later the HWWD tripped at 22:20:33

Images attached to this report

H1 CDS - OMC DCPD cable pins wiring confusion

elenna.capote@ligo.org — Tue, 24 Mar 2026 12:53:13 -0700

Author: elenna.capote@ligo.org

Report ID: 89621

We previously reported that the wiring to ground on the OMCA DCPD dsub9 cables seemed odd, see 89562. There appears to be two conflicting diagrams of the pin wiring, D2200276 and D2300119. Neither of these diagrams follow the correct pin naming practice either.

Today, Oli and I checked the ground connectivity for the OMCB DCPD dsub9. The case ground is wired to what is labeled pins 6 and 9, according to both of the diagrams above and also proper convention. However, this is different from OMCA, where the case ground is wired to pins 2 and 5 (following the incorrect naming of the diagrams above), or pins 1 and 4 (following correct naming conventions).

So either way, we have two different wiring set ups for OMCA and OMCB. We have only checked the ground pins so far, and it seems like we should confirm the cathode and anode wiring as well.

To summarize:

- we have two different diagrams for pin wiring

- OMCA and OMCB are wired differently from each other

- the diagrams are not following proper pin naming convention which is making this more confusing

AOS, CDS, ISC

LHO VE - Tue CP1 Fill

david.barker@ligo.org — Tue, 24 Mar 2026 12:22:58 -0700

Author: david.barker@ligo.org

Report ID: 89620

Tue Mar 24 10:06:11 2026 INFO: Fill completed in 6min 7secs

Images attached to this report

H1 CDS - Comment to Recovering SWWD and HWWD trips after Mon 21:45 PDT earthquake

david.barker@ligo.org — Tue, 24 Mar 2026 10:25:38 -0700

Author: david.barker@ligo.org

Report ID: 89618

Fil got the ITMY HWWD to fully reset by keeping the "fault reset" button pressed for many seconds.

H1 ISC - BHSS / BHD work Mar 23: OMCB almost done, OMCA ready for alignment!

oli.patane@ligo.org — Tue, 24 Mar 2026 10:17:44 -0700

Author: oli.patane@ligo.org

Report ID: 89615

Elenna, Oli

Summary: OMCB has its DCPDs installed and most of its stoppers (barring one that needs to be retapped + helicoiled). OMCA has been aligned according to the OMCA / OMCB install template and is ready for laser alignment. Cabling for both OMCs should be good to go.

After last week's issue of the OMCB DCPD A (TRANS) missing a diode hole (89583), we were able to clear up the issue and fix it (89606). Elenna then installed the DCPD B (REFL) diode. Note that once again there were tiny metal shavings below where the DCPD's were installed, which we picked up with a qtip that we wet with iso. Once we had both installed (pic), we installed the rest of the stoppers around OMCB. The only one we didn't install is one of the vertical stops. This is because there was an issue with the helicoil last week, and we ended up having to remove it. We think this might be due to an issue with the threads, so we are waiting on a 3/8"-24 tap to retap the hole before installing a new helicoil. Because we don't have this stop yet, it doesn't really make sense to fasten on the butter dish, but we might just sit it on today to hinder dust accumulation.

We also realized that the PZT cables were going to be way too short to reach the cable pylons for both OMCA and OMCB, so we very carefully opened the peak cable wraps on the OMCs and took out what we think should be enough. On OMCB we noticed that the little copper wrap for one of the PZTs was not right above the PZT as it should be, but instead was on the other side of the peak cable wrap and was only wrapped loosly around one of the cables. Because of this we just removed the wrap. The cables right above the PZT are looking fine and don't look like they need anything to hold them together.

I had been confused about the OMCA / OMCB install template for the past few days, since installing it was putting OMCB further back in its slot than OMCA, but I was able to confirm yesterday in eDrawings that OMCB is actually supposed to be an extra 1 mm away from the front of its slot as compared to OMCA, so we moved OMCA into position and bolted it down.

I also went in and installed the magnet mounts for the OSEM magnets (without the magnets), as well as the big mass on the back of the BHSS.

Installed serial numbers:

OMCB (SN 105)

DCPD A (TRANS)
- DCPD: 1C-14
- Housing: SN 002
DCPD B (REFL)
- DCPD: 1C-10
- Housing: SN 008

SUS

Images attached to this report

H1 PEM - Comment to 3-month Trend of Dust Counts At BSC2

betsy.weaver@ligo.org — Tue, 24 Mar 2026 10:11:29 -0700

Author: betsy.weaver@ligo.org

Report ID: 89617

Calum and I looked over this plot - the counts are not too bad during the many periods of nearby craning and other activity. The platform and dome have not yet been cleaned. I confirmed that the cross flow tent has positive pressure so Calum and I are comfortable with this new "cleanroom" configuration.

H1 TCS - CO2Y Tripped off, back on now.

camilla.compton@ligo.org — Tue, 24 Mar 2026 09:20:31 -0700

Author: camilla.compton@ligo.org

Report ID: 89616

Yesterday during the cleanroom move, CO2Y tripped off, this is a known issue when people get near the TCS racks, FRS 6639. I turned it back on this morning by pressing the "GATE" button on the chassis.

LHO General - Comment to Tues DAY Ops Transition: Maintenance Day

corey.gray@ligo.org — Tue, 24 Mar 2026 08:49:14 -0700

Author: corey.gray@ligo.org

Report ID: 89614

Earthquake Recovery Status:

~~ITMy Hardware Watchdog continues to be looked at with Fil/Jonathan~~

UPDATE: Fil was able to restore the ITMy watchdog (he held the RESET for a few seconds and waited for the lights to change on the front panel). ITMy HEPI/ISI are redamping/isolating.

HAMs restored: HAM1/2/3/4/5/7/8
BSCs restored: ETMy/BS/ITMy/ETMx/ITMx
- HEPIs restored: ETMy/ITMy/ITMx
Software Watchdogs restored:
- ETMy: SUS & SEI
- ITMy: SUS & SEI
- ITMx: SUS & SEI
Hardware Watchdog tripped: ITMy (just got restored by Fil)

CDS, SEI, SUS

H1 CDS - Recovering SWWD and HWWD trips after Mon 21:45 PDT earthquake

david.barker@ligo.org — Tue, 24 Mar 2026 08:38:11 -0700

Author: david.barker@ligo.org

Report ID: 89613

Corey, Fil, Erik, Jonathan, Dave:

Last night's earthquake caused SWWD trips for ETMY, ITMY, ITMX. It also caused a HWWD trip of ITMY (BSC1) which was concerning.

We were able to untrip the SWWDs, but we kept ITMY DACKILLED while we work on its HWWD.

Jonathan went into the CER and pressed the RESET button on the ITMY HWWD chassis, this did not untrip the power to the ISI coil drivers. We tried a second time, again no restoration of power.

The front panel and the readback by h1susitmy both agree that the only red led is SEI-trip, the input conditions PD=osem-photodiode-rms and LED=osem-led-current are both GOOD, which should have permitted the reset.

But when the reset button was pressed, the PD led went RED and the unit did not reset the SEI trip.

Fil is heading out to reboot the unit and possibly replace with a spare if it is not working correcty.

Images attached to this report

LHO General - Tues DAY Ops Transition: Maintenance Day

corey.gray@ligo.org — Tue, 24 Mar 2026 07:52:27 -0700

Author: corey.gray@ligo.org

Report ID: 89611

TITLE: 03/24 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: 14mph Gusts, 10mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.19 μm/s
QUICK SUMMARY:

Arrived to see lots of tripped Watchdogs. This was due to a M7.5 Tonga earthquake from last night just before 10pm local time (5utc). Dave contacted me to give me the heads up on this and noted that ITMy actually had the Hardware Watchdog trip---this requires someone to go out to the CER to push a button to restore coil drivers. We were hesitant on addressing this without Jim's guidance--not sure how powering things back on would affect the system. Will message Jim with a heads up for BSC1's ITMy/BSC1-ISI/BSC1-HEPI. Will continue bringing everything else back.

Other than that, today is Maintenance Day. The Filter Cavity Tube has light flashing and so its small gate valves must still be open (I had thought the discussion was to close these gate valves to allow craning over the FC Tube, but not certain on this.

Day1 of 2-day CEBEX workshop begins today.

H1 CDS - Workstations updated

erik.vonreis@ligo.org — Tue, 24 Mar 2026 07:23:47 -0700

Author: erik.vonreis@ligo.org

Report ID: 89610

Workstations updated and rebooted.