aLIGO LHO Logbook

H1 General - OPS Tuesday Day shift start

ryan.crouch@ligo.org — Tue, 02 Jun 2026 07:30:34 -0700

Author: ryan.crouch@ligo.org

Report ID: 90434

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

H1 CDS - Comtrol power supply replaced at EY

erik.vonreis@ligo.org — Tue, 02 Jun 2026 07:07:07 -0700

Author: erik.vonreis@ligo.org

Report ID: 90433

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.

CDS

H1 CDS - Workstations updated

erik.vonreis@ligo.org — Tue, 02 Jun 2026 07:05:17 -0700

Author: erik.vonreis@ligo.org

Report ID: 90432

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

CDS

LHO VE - Corner station vent update

travis.sadecki@ligo.org — Mon, 01 Jun 2026 19:55:46 -0700

Author: travis.sadecki@ligo.org

Report ID: 90431

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.

Images attached to this report

H1 IOO - HAM1/2/3 alignment Monday (Disha, Rahul, Jenne, Keita)

keita.kawabe@ligo.org — Mon, 01 Jun 2026 19:29:04 -0700

Author: keita.kawabe@ligo.org

Report ID: 90430

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.)

IOO

Images attached to this report

H1 SEI - CRS progress log

arnaud.pele@ligo.org — Mon, 01 Jun 2026 18:17:58 -0700

Author: arnaud.pele@ligo.org

Report ID: 90429

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

Images attached to this report

H1 CDS - WP 13286 Migrating the fmcs IOC off of the mac mini failed

jonathan.hanks@ligo.org — Mon, 01 Jun 2026 17:06:47 -0700

Author: jonathan.hanks@ligo.org

Report ID: 90428

As per WP 13286 I tested the copy of the fmcs epics ioc that I had extracted from fmcs-epics-cds. Unfortunately the IOC would crash each time I ran it. There was not time to debug and see if it could be fixed today. So the mac mini is still running the ioc.

H1 AOS - HAM7 started placing irises

sheila.dwyer@ligo.org — Mon, 01 Jun 2026 17:03:03 -0700

Author: sheila.dwyer@ligo.org

Report ID: 90426

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.

Images attached to this report

H1 CDS - Comment to Model restart and DAQ restart

jonathan.hanks@ligo.org — Mon, 01 Jun 2026 17:00:24 -0700

Author: jonathan.hanks@ligo.org

Report ID: 90427

The following channels where removed from the broadcast list:

H1:SUS-BS_M1_DAMP_L_IN1_DQ
H1:SUS-BS_M1_DAMP_P_IN1_DQ
H1:SUS-BS_M1_DAMP_R_IN1_DQ
H1:SUS-BS_M1_DAMP_T_IN1_DQ
H1:SUS-BS_M1_DAMP_V_IN1_DQ
H1:SUS-BS_M1_DAMP_Y_IN1_DQ
H1:SUS-BS_M2_WIT_L_DQ
H1:SUS-BS_M2_WIT_P_DQ
H1:SUS-BS_M2_WIT_Y_DQ
H1:SUS-BS_M3_OPLEV_PIT_OUT_DQ
H1:SUS-BS_M3_OPLEV_SUM_OUT_DQ
H1:SUS-BS_M3_OPLEV_YAW_OUT_DQ

They were replaced by BBSS variants:

H1:SUS-BBSS_M1_DAMP_L_IN1_DQ
H1:SUS-BBSS_M1_DAMP_P_IN1_DQ
H1:SUS-BBSS_M1_DAMP_R_IN1_DQ
H1:SUS-BBSS_M1_DAMP_T_IN1_DQ
H1:SUS-BBSS_M1_DAMP_V_IN1_DQ
H1:SUS-BBSS_M1_DAMP_Y_IN1_DQ
H1:SUS-BBSS_M2_WIT_L_DQ
H1:SUS-BBSS_M2_WIT_P_DQ
H1:SUS-BBSS_M2_WIT_Y_DQ
H1:SUS-BBSS_M3_OPLEV_PIT_OUT_DQ
H1:SUS-BBSS_M3_OPLEV_SUM_OUT_DQ
H1:SUS-BBSS_M3_OPLEV_YAW_OUT_DQ

We are told in a future update the original names will be restored.

H1 AOS - Quad cage baffles staged for ITMY

anamaria.effler@ligo.org — Mon, 01 Jun 2026 16:38:58 -0700

Author: anamaria.effler@ligo.org

Report ID: 90425

Betsy, Anamaria

With the helpful kits Mitchell had prepared, we assembled the cage baffle brackets and panels on a table by BSC1; this includes CP and HR cage baffles. We chose SN 3's for ITMY and SN 4's for ITMX for both panels and brackets. We also checked that we have the various tools we need chamber side. Still need to make one more set of brackets for ITMX CP baffle, but that can wait. We found and staged two ACB long lockers but only one wedge.

LHO General - Ops Day Shift Summary

ryan.short@ligo.org — Mon, 01 Jun 2026 16:35:58 -0700

Author: ryan.short@ligo.org

Report ID: 90424

TITLE: 06/01 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Very busy day with lots of visitors on site! Essentially everything was recovered following the weekend power outage, doors on HAM7 were removed and SQZ work in the chamber started after the ISI was locked, QOSEM work continued on the BBSS, the ISI was balanced on the test stand, prep began for the ITM cage baffle installation, GV7 was cycled and left closed for venting of the X-manifold, more beam alignment went on in HAMs 2 and 3, turbopumps at EY and MY were tested, FARO surveying began in HAM3, CRS building continued, and SPI work in the optics lab is ongoing. The EDC is still showing several disconnected channels, some of which relate to EY dust monitors.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
19:29	SAF	Laser HAZARD	LVEA	YES	LVEA is Laser HAZARD	17:21
14:36	FAC	Kim	LVEA	-	Technical cleaning	17:01
14:43	FAC	Randy	LVEA	-	Prep for HAM7 doors	15:12
15:01	VAC	Jordan	LVEA	-	Checking pumps	15:10
15:37	SPI	Jeff	Opt Lab	Local	Turning on laser	17:00
15:38	IAS	Ryan C	LVEA	-	Checking on FARO	15:47
15:46	ISC	Keita	LVEA	-	Opening light pipe	15:48
15:46	VAC	Jordan	MY, EY	-	Turbopump checks	16:40
16:04	PSL	Jason	LVEA	-	Powering on PSL CB2	16:22
16:19	VAC	Travis	Lvea	-	HAM7 door prep	16:25
16:28	SAF	Ibrahim	LVEA	-	Transition to SAFE	17:21
16:54	SUS	Oli, Tom	LVEA	-	BBSS QOSEM	18:19
17:21	SUS	Ibrahim	LVEA	-	BBSS work	18:19
17:22	FAC	Randy	LVEA	-	HAM7 door removal	19:22
17:22	VAC	Travis, Jordan	LVEA	-	HAM7 door removal	18:40
17:22	FAC	Kim	EX, EY	-	Technical cleaning	18:19
17:24	CDS	Erik	EY, EX	-	Power outage recovery	18:27
17:29	VAC	Gerardo	LVEA	-	HAM7 door removal	18:41
17:33	SLiC	Mitch, Anamaria	LVEA	-	Baffle install planning	17:46
17:38	SPI	Corey	Opt Lab	-	Optic cleaning	19:46
18:15	IAS	Jason, Ryan C	LVEA	-	FARO surveying HAM3	20:33
19:04	SAF	Sheila	LVEA	YES	Transition to Laser HAZARD	19:26
19:09	TCS	Camilla	MER	-	Turning on TCS chillers	19:25
19:26	SAF	Laser HAZARD	LVEA	YES	LVEA is Laser HAZARD	Ongoing
19:27	SEI	Shoshana, Arnaud	H2 PSL	-	CRS builds	19:53
19:34	SEI	Jim	LVEA	-	Locking HAM7 ISI	19:54
19:55	SEI	Jim	EX, EY	-	Bringing up HEPI	20:33
20:13	SPI	Jeff, Sina	Opt Lab	Local	SPI alignment	22:04
20:24	VAC	Jordan, Jake, Owen	EY, MY	-	Shutting down turbopumps	21:20
20:33	ISC	Marc, Keita	CER	-	PZT power supply	20:37
20:50	SLiC	Betsy, Anamaria	LVEA	-	Staging for baffle install (Anamaria out @ 23:04)	Ongoing
20:59	SEI	Jim, Ibrahim	LVEA	-	BBSS ISI balancing	Ongoing
21:08	VAC	Travis, Gerardo	LVEA	-	X-man vent and open GV2 (Gerardo out @ 23:03)	Ongoing
21:24	VAC	Jordan, Jake, Owen	LVEA	-	X-man vent and open GV2	22:18
21:28	SEI	Marc, Patrick	MER	-	HEPI electronics	21:58
21:30	SQZ	Sheila, Camilla	LVEA	Y	HAM7 SQZ beam hunting (Camilla out @ 22:58)	Ongoing
21:38	IAS	Jason, Ryan C	LVEA	-	FARO surveying HAM3	Ongoing
21:58	ISC	Keita, Rahul, Disha	LVEA	Y	HAM2/3 beam alignment	Ongoing
22:04	SEI	Arnaud, Shoshana, Alex	H2 PSL	-	CRS builds (Alex out @ 23:11)	Ongoing
22:32	VAC	Jordan, Jake, Owen	LVEA	-	Venting X-manifold	Ongoing
22:35	SPI	Jeff, Sina	Opt Lab	Local	SPI alignment (Jeff out @ 23:05)	Ongoing
23:18	AOS	Mitchell	LVEA	-	Delivering garb	Ongoing

H1 CDS - Model restart and DAQ restart

erik.vonreis@ligo.org — Mon, 01 Jun 2026 14:55:03 -0700

Author: erik.vonreis@ligo.org

Report ID: 90422

[Jonathon, Ollie, Erik v., Tom]

h1susbs front end model was shut down and h1suslo12 was rebuilt and restarted, moving control of mc2 form h1susbs to h1suslo12.

This required DAQ and EDCU restarts. The DAQ restart ran into problems because some channes were renamed (temporarily, hopefully) from BS to BBSS that were part of the GDS broadcast. These channels have been renamed in the broadcaster lists for h1daqgds0 and g1daqgds1.

H1 IOO - JAC recovery from power outage (Ryan, Patrick, Marc, Rahul, Jenne, Keita)

keita.kawabe@ligo.org — Mon, 01 Jun 2026 14:54:40 -0700

Author: keita.kawabe@ligo.org

Report ID: 90421

JAC PZT HV was off -> Mark reset the interlock.

JAC heater chassis was off -> I switched it on at the rack.

JAC error signal was not crossing zero -> I updated the dark offset H1:JAC-REFL_A_RF43_I_OFFSET to a new number 2.4.

Beckhoff was reporting "invalid value" error for JAC PZT whitening -> Patrick did something to clear that.

Rahul restored slider numbers for JM1/3, IMC1/2/3, IM1/2/3/4 and PRM to Friday evening numbers as he reported in alog 90419.

JAC guardian didn't want to lock because H1:JAC-TRANS_A_DC_NORMALIZED kept getting below the threshold of 0.5. -> I temporarily changed it to 0.1.

JAC PZT voltage was drifting quickly for 30 minutes or so and JAC kept unlocking (probably because JAC was heating up) -> waited for a while.

JAC still didn't want to keep lock for a long time. -> I put it to DOWN state, followed the resonance manually using the PZT voltage for a minute or so, changed the state to LOCKED and the guardian liked that.

Jenne refined the JAC alignment using PZT and JM1. H1:JAC-TRANS_A_LF_OUT_DQ momentarily went up to 620 and the best number in the past month before today was like 580. It's trending down in the past two hours, now it's ~580 and that's still a very good number.

Temperature drift is still going on, the symptom is that the PZT voltage drifts down to -10 Volts and at that point JAC unlocks, but the guardian relocks to higher voltage fringe position right away, and the drift is slow enough it's bearable. Last lock lasted for an hour.

Now we can set H1:JAC-TRANS_A_DC_NORMALIZED back to 0.5 if we want to.

IOO, ISC

H1 ISC - Quick notebook script to calculate pit/yaw values when beam is flashing

jenne.driggers@ligo.org — Mon, 01 Jun 2026 14:24:05 -0700

Author: jenne.driggers@ligo.org

Report ID: 90420

Aligning beams onto QPDs while the IMC is flashing (eg, during a vent) is very challenging. We want to know what the pit and yaw values are, but can only trust the values at a moment when there is a flash.

The jupyter notebook that has just been placed into git can (with lots of patient help from Jamie Rollins) read data that has been exported from an ndscope (so, can be data that is not DQ'd), and then will calculate the pitch and yaw values at the time of the largest flash in that time window.

This is a direct link to the notebook right now for a snapshot of this first iteration, and you can see the plots at the very end and a printout of the pit/yaw values of all of the QPDs that I have collected data for.

Hopefully this will help make things a bit quicker as we work to center on our various ASC PDs and close out this vent.

H1 SUS - SUS alignment sliders for HAM1_2_3 restored to Friday evening (6.30pm) values

rahul.kumar@ligo.org — Mon, 01 Jun 2026 14:20:18 -0700

Author: rahul.kumar@ligo.org

Report ID: 90419

I have restored the SUS alignment slider values (P/Y) for all the suspensions in HAM1, 2 and 3 chambers (i.e JM1, JM3, MC1, MC2,, IM1, IM2, IM3, IM4) which had changed after the Saturday site power outage. I trended the pitch and yaw slider values for all of the suspensions in these three chambers and restored the ones which I found have changed. I selected Friday evening (29 May 2026, 6.30 PM when Keita et al were done with moving the suspensions).

SUS

Images attached to this report

H1 SQZ - HAM7 HiVoltage Bypass On

camilla.compton@ligo.org — Mon, 01 Jun 2026 14:05:14 -0700

Author: camilla.compton@ligo.org

Report ID: 90418

Marc and I turned on the HAM7 Hi Voltage Bypass in the Mech Rm Mezzanine. We first turned the PSAMS down to zero, they hadn't been zero'ed before Hi-voltage was turned off. WP13282

H1 IOO - IMC, IM2/3/4 and PRM are aligned, cannot center ASC REFL sensors (JennieW, Rahul, Keita)

keita.kawabe@ligo.org — Mon, 01 Jun 2026 12:34:10 -0700

Author: keita.kawabe@ligo.org

Report ID: 90404

Belated alog from Friday.

Summary:

After realigning IMC and IM2 on Thursday, we continued aligning IM3 to put the beam in front of the PRM to the nominal position, IM4 to set the beam position in front of PR2, and PRM so the beam retroreflects. IM1 was left untouched, so the only change in IM1-IM2 line is from the change in the IMC alignment.

Clipping on IM4 baffle (HA12) disappeared completely. Beam position on IFI output baffle looked OK. Beam position on IFI input baffle didn't change (as expected) and still looked OK. There are some mystery

We saw flashes on ASC REFL sensors but they were weak. We tried to center them using RMs but RM2 seems to rail in YAW.

	Before P, Y [urad]	After P, Y	difference P,Y
RM1	-196, 281.8	-242, -19.3	-46, -301.1
RM2	910, 490	912.1, -2125.15 (railing)	+2.1, -2615.15

What to do:

Scan PRM to make sure that we're NOT looking at some kind of ghost beam on ASC REFL sensors.

Assuming that we're looking at the real beam on REFL sensors, we can do either (or some of) these:

Relieve RM2 by rotating RH9 (the fixed IFO refl pick off mirror in HAM2) by positive 500urad or so in YAW. This is the equivalent of the combination of negative 0.53 mrad for RM1 and negative 2mrad for RM2 in YAW. After doing this we can add 530urad to RM1 and 2000urad and continue centering from there. See attached cartoon (doesn't scale but the sign of things is correct) and the script.
IM1 is almost degenerate as RH9 as far as relieving RM1 and RM2 is concerned, so we can rotate IM1 by negative 500urad or so in YAW. This requires that we tweak IM3, IM4 and PRM again but has an added benefit of moving the beam spot on the IFI input baffle closer to the center. See IM1rotation.png.
- If you aren't sure how IM1 rotation is translated to the IFO refl beam, IM1rotation_straightened.png is a simplified and unfolded version. The beam going out of IM1 goes through CWP at the IFI input (deflected but it's not written in the cartoon for simplicity), is retroreflected and comes back to CWP and defflected, the deflection for the REFL beam is depicted here. Without IM1 rotation the beam goes along the black path. With IM1 rotation (red path), the red refl beam converges with the black refl beam where the distance from the conversion point to the CWP is equal to that from the IM1 to CWP. The angle change of REFL is the same with the input and the lateral displacement of red refl relative to black is ~(distance(IM1_CWP)-distance(RH9_CWP))*angle_change.
Make the OSEM coil driver output impedance smaller for RMs to gain more range. 1.2k to 500 Ohm should be safe.

INS, IOO, ISC

Images attached to this report

Non-image files attached to this report

REFL_VS_IMs.m

H1 TCS - TCS CO2 Chillers turned back on after power outage

camilla.compton@ligo.org — Mon, 01 Jun 2026 12:22:50 -0700

Author: camilla.compton@ligo.org

Report ID: 90416

Both CO2X and CO2Y Chillers turned back on with no issue. Interestingly as the laser is off they are currently heating the water.

H1 CDS - CDS Recovery Status

david.barker@ligo.org — Mon, 01 Jun 2026 11:41:44 -0700

Author: david.barker@ligo.org

Report ID: 90414

All CDS systems have been recovered with the exception of EY dust monitor. The EY Comtrol serial-to-ethernet is not working, Erik is replacing its power supply.

Erik started the HWS code. At EX he powered up the h1cdsrfm expansion chassis and power cycled the BRS_EX. At EY he powered the expansion chassis.

We started h1cdsrfm which has cleared all the long-range-dolphin IPC errors. EY WAP just needed powering up via the Pulizzi.

Patrick started the code on the Beckhoff systems for CHILLER_CS, CHILLER_EX, BRS_EX, BRS_EY, NCALX and MAINS_EX.

EDC is currently down to 16 disconnected channels, all EY_DUST.

H1 IOO - Comment to IMC, IM2/3/4 and PRM are aligned, cannot center ASC REFL sensors (JennieW, Rahul, Keita)

keita.kawabe@ligo.org — Mon, 01 Jun 2026 11:36:55 -0700

Author: keita.kawabe@ligo.org

Report ID: 90412

Baffle pictures. Whenever appropriate, there are two pictures (one to access PIT and the other to access YAW) to avoid the parallax problem as the thickness of the baffles cannot be ignored.

IFO REFL looks good on the IFO REFL baffle (HA13) in front of the HAM2-HAM1 septum window (IFO_REFL_HA13.jpg).

IM4 baffle (HA12) is good in PIT (IM4_HA12_PIT_good.jpg), not great in YAW but is OK (IM4_HA12_YAW_OFF.jpg). Next time I'll take a picture through IM4 to show you it's quite acceptable than it looks from these pictures.

IR picture of the IM4 baffle (HA12) shot from IM3 side shows a ghost beam it catches when there's a flash (IM4_HA12_ghostbeam.jpg). Circled in red is the ghost beam (in this case it was 10 mode flash). Circled in green are things that are always visible (IM4_HA12_noflash.jpg) and aren't the ghost beam.

IFI input beam position is great in PIT, not great in YAW (IFI_INPUT_PIT_GREAT_YAW_OFF.jpg, IFI_INPUT_PIT_GREAT.jpg).

However, I still see some kind of clipping of bacdkward-going beam once in a while. See the IR photo shot from IM3 direction IFI_INPUT_clipping.jpg. You're looking at the baffle aperture through calcite wedge from the direction of IM1. Compare with IFI_INPUT_noflash.jpg where there was no flashing.

Not every flash shows this clipping-like thing, it seems to happen less frequently than the flashing.

To make things more confusing, there's a reflection of something shiny in IFI and the edge of that shiny thing is almost on top of the edge of the IFI input baffle aperture so it's hard to say what's going on. Nothing like this was visible on the input side facing IM2.

We temporarily moved IM1 to move the beam spot on IM2 more centered (IFI_INPUT_IM1movedtocenter.jpg) and I can see something closer to the center (probably scattering from the CWP?) but no clipping. So probably it's a good thing to move IM1 counter-clockwise as I indicated in the alog above. We cannot do it too much as we rail RM2 in the opposite direction, but we can probably move the beam by a mm or so on IM2.

Images attached to this report

H1 SPI - 2026-06-01 SPI Pathfinder Power Outage Recovery: No issues

jeffrey.kissel@ligo.org — Mon, 01 Jun 2026 11:30:04 -0700

Author: jeffrey.kissel@ligo.org

Report ID: 90413

J. Kissel" As is all over the aLOG this morning, LHO had back-to-back site-wide power-outages this past Saturday 2025-05-30 -- LHO:90395. Here's the quick, pain-free record of recovering the SPI pathfinder's function to the levels we left it on Friday 2026-05-29 (LHO:90382). LASER State of laser as I found it (entering the lab with laser safety googles ON): - Yellow chain and signage across the entry warning of "laser running unattended" still blocking entry. - Magnetic lock of "outer" curtain released, manually hook-locked "inner" curtain still closed. - Laser hazard sign OFF - Laser STOP Button still "OUT" (in the ON position) - Laser Hazard sign still keyed "ON" - NPRO shuttered, still keyed ON, but not powered. In short -- everything worked as expected in the event of a power outage if it happened while a laser system was running unattended. RECOVERY (all with laser safety glasses ON; obviously but just saying it "out loud"): - Unchained and stored "unattended laser" sign. - Pushed in ("OFF") laser stop button. - Keyed OFF laser hazard sign. - Pulled out ("ON") laser stop button to allow for re-energizing of interlock. - Keyed ON laser hazard sign. - Closed magnetic "outer" curtain and swiped in, laser hazard sign lit up as expected. - Confirmed NPRO laser output is shuttered. - Looked at NPRO controller, red light ON under the OFF button (as expected because it was already/still keyed ON). - Plugged in and turned on PD100D interface for on-board S304C power monitor PD (installed within the laser conditioning/fiber collimating bread-board), confirming 1064 [nm] wavelength readout settings. - Waited ~2 minutes for the diodes' controllers to settle, then hit the green ON button - No issues with diode temp transients, laser worked just fine. - Unshuttered laser, and on-board S304C power monitor PD happily confirmed the expect ~198 [mW]. ELECTRONICS State of electronics as I found it: - Electronics +/-18 V and +/-24.0 V power supplies were ON, with their outputs producing voltage at their nominal settings. - Laser prep chassis and PD TIA chassis all showed happy green lights. - Keysight 33600A RF source had reset, with outputs off and all the wrong settings. RECOVERY (all with laser safety glasses ON; obviously but just saying it "out loud"): - Ran through T2600039 to restore all frequency settings - Exported March 2026 notes to LHO:90409 and restored CH1 (REF) and CH2 (MEAS) amplitude settings to -1.7 and -1.4 [dBm], respectively - Turned CH1 and CH2 output ON. Laser Prep Chassis SM05PD01A monitor PD ADC voltage: 7.83 [V]. Laser Prep Chassis RF monitors M2 (REF) and M3 (MEAS) ADC voltage: ~750 and ~750 [mV] FBR_PWRIN_REF On-board power monitor PD ADC voltage: 4.68 [V]. In short :: All these monitor ADC voltages are at normal values. SPI IFOs No actions required after turning on LASER and ELECTRONICS. REF IFO Efficiency -- 4.96 V / (2 * 2.69V) = 0.922 MEAS IFO Efficiency -- 3.00 V / (2*3.95 V) = 0.38 Recovered! Hopping back into The Mystery Machine...CDS, Laser Safety

H1 TCS - Started to assemble D1700340-type02 for CHETA VPs

camilla.compton@ligo.org — Mon, 01 Jun 2026 10:31:57 -0700

Author: camilla.compton@ligo.org

Report ID: 90411

Gerardo, Jordan, Camilla.

On Thursday we assembled VAC sealing part of the CHETA VPs, D1700340-type02. The thinnest part of the optics are at 12o'clock if the VP is oriented with the P/N of D1700338 writing also ~12o'clock.

D1700338-v2-001 with D1700339-v2-001 and D1700338-v2-003 with D1700339-v2-003. Both have optics D1100439-type02, which are DAR coated for 1064nm and 10.6um.

Next steps is VAC testing, then first contact the window surfaces and add secondary window.

Images attached to this report

H1 CDS - Comment to State of CDS following recovery from second power outage

erik.vonreis@ligo.org — Mon, 01 Jun 2026 10:03:56 -0700

Author: erik.vonreis@ligo.org

Report ID: 90410

h1hwsex and h1hwsey are running in a tmux session. To get to the process, ssh as controls to the server and run "tmux a".

H1 SPI - Comment to SPI, Prep Chassis RF Input Chain to Monitor output Chassis

jeffrey.kissel@ligo.org — Mon, 01 Jun 2026 09:12:21 -0700

Author: jeffrey.kissel@ligo.org

Report ID: 90409

J. Kissel Easy look up table after setting up Keysight 33600A per T2600039, and setting the amplitudes as we have had for most of the build :: CH1 = AMP 1 = REF = M2 MON f = 79.995904 MHz (79,995,904 Hz) amp = -1.7 dBm M2 MON = 740 mV CH2 = AMP 2 = MEAS = M3 MON f = 80.000000 MHz (80,000,000 Hz) amp = -1.4 dBm M3 MON = 755 mV Remember to turn the output ON for each channel.SPI

LHO General - Comment to Ops Day Shift Start

ryan.short@ligo.org — Mon, 01 Jun 2026 08:24:04 -0700

Author: ryan.short@ligo.org

Report ID: 90408

Current status:

Cannot remote login to PSL computer to restart the laser
- I expect I won't be able to power it on anyway as the benchtop power supply in the PSL racks powering CB2 probably needs to be turned back on manually
- Site laser interlock is tripped too; can't reset since PSL Beckoff is down
HEPI_ETM{X,Y} and CDS_CA_COPY Guardian nodes were in error, reloading fixed
- Guardian machine does not seem to have gone down as nodes all look okay
All suspesnions recovered (except BS and ITMs, did not touch these)
All HEPI pump stations are down, cannot untrip HEPI
- Not untripping ISIs while HEPIs are down
ISI HAM8 recovered, ISI HAM7 recovered but then quickly tripped again (chamber is vented, makes some sense)
~~Cannot seem to trend any data via ndscope before the outage on Saturday~~
End BRSs are down (if Beckhoff is still down, this makes sense)

LHO General - Ops Day Shift Start

ryan.short@ligo.org — Mon, 01 Jun 2026 07:39:00 -0700

Author: ryan.short@ligo.org

Report ID: 90407

TITLE: 06/01 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: 7mph Gusts, 5mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.16 μm/s
QUICK SUMMARY: Will continue recovery of various sytems following power outages over the weekend and will work on discovering what still needs attention.

H1 CDS - Comment to State of CDS following recovery from second power outage

david.barker@ligo.org — Mon, 01 Jun 2026 07:36:27 -0700

Author: david.barker@ligo.org

Report ID: 90406

Here are all the MSR UPS Emails we received on Saturday. The UPS clock appears to be incorrect and about 14mins fast. No GC UPS emails were received on Saturday.

Sat Morning Outage 09:39

Date: 05/30/2026
Time: 10:12:59
Code: 0x0002
Critical - System: Warmstart. (2 copies received)

Date: 05/30/2026
Time: 10:13:06
Code: 0x0101
Informational - UPS: Restored the local network management interface-to-UPS communication.

Sat Afternoon Outage 14:27

Date: 05/30/2026
Time: 14:45:38
Code: 0x020F
Critical - UPS: An input voltage or frequency problem prevents switching to bypass mode. (4 copies received)

Date: 05/30/2026
Time: 14:45:40
Code: 0x0109
Warning - UPS: On battery power in response to an input power problem. (2 copies received)

Date: 05/30/2026
Time: 14:45:45
Code: 0x010A
Informational - UPS: No longer on battery power. (2 copies received)

Date: 05/30/2026
Time: 14:45:57
Code: 0x0210
Informational - UPS: An input voltage or frequency problem no longer prevents switching to bypass mode. (2 copies received)

H1 IOO - Comment to IMC, IM2/3/4 and PRM are aligned, cannot center ASC REFL sensors (JennieW, Rahul, Keita)

keita.kawabe@ligo.org — Mon, 01 Jun 2026 01:09:50 -0700

Author: keita.kawabe@ligo.org

Report ID: 90405

See screenshot for before/after slider values for RM, IM and other optics.

Images attached to this report

H1 CDS - State of CDS following recovery from second power outage

david.barker@ligo.org — Sun, 31 May 2026 09:36:53 -0700

Author: david.barker@ligo.org

Report ID: 90403

Thankfully no more power outages following the second (14:27) outage Sat 30may2026. Here are the systems we left offline which will be restarted tomorrow, Mon 01jun2026.

PSL Diode Room Beckhoff Controls

Long range dolphin end station Adnaco expansion chassis (h1cdsrfm)

NCAL EX

BRS EX, EY

HWS EX, EY

MAINSMON EX

CHILLERMON EX, EY

LHO FMCS - Site Power Issue - FAC Recovery pt. 2

tyler.guidry@ligo.org — Sat, 30 May 2026 18:56:05 -0700

Author: tyler.guidry@ligo.org

Report ID: 90402

The second outage took the end station chillers down again. Jordan V restored power to the CWPs, and I cleared all alarms remotely. Temps rose a couple degrees at each end to just under 70f. Those should correct quickly, if not already. R. McCarthy J. Vanosky T. Guidry

LHO VE - Replacement of Purge Air Compressor HMI Screen

jordan.vanosky@ligo.org — Sat, 30 May 2026 18:44:28 -0700

Author: jordan.vanosky@ligo.org

Report ID: 90401

After the failure of the compressors HMI last week, see alog 90318. A tech from Rogers Machinery (Brandon) came on site today to install a new HMI unit. The compressor had to be powered off to make the swap, so I isolated the purge air from the LVEA at the ball valve just past the drying towers.

The HMI swap was pretty quick only took about 10 minutes, and we can now see the temperatures and pressures in the compressor. I let the purge air skid run for ~10 minutes to make sure the dewpoint was stable, at -75C, then opened back to the LVEA.

The replacement oil pump should be delivered next week, at which time a tech will have to come out again and make the swap.

Images attached to this report

H1 CDS - Staging a quick replacement for fmcs-epics-cds (fmcs ioc mini)

jonathan.hanks@ligo.org — Sat, 30 May 2026 18:16:14 -0700

Author: jonathan.hanks@ligo.org

Report ID: 90400

In the two power issues today Erik had to manually start fmcs-epics-ioc. It is a mac mini in a custom rack container that makes it hard to see if it is on or to power cycle it. This machine causes issues at each power outage.

After the second outage I put a VM together to host a containerized version of the code. It is staged and ready to go, but not tested. If it goes down again we go onto the new system and start the container. It should allows to get the fmcs going without sending someone to fiddle with the machine.

To do this:

1. log into fmcs-epics-ioc.

2. systemctl start deb10ioc

To make it perminant we need to modify the systemd file to have an install section, do a daemon-reload and a systemctl enable.

Ultimately we need to rebuild this ioc on a new OS release.

LHO VE - Comment to VAC Recovery After Site Power Issue

jordan.vanosky@ligo.org — Sat, 30 May 2026 16:48:42 -0700

Author: jordan.vanosky@ligo.org

Report ID: 90399

Well, it's Groundhog Day...again.

Came out to the site after the 2nd power glitch. The same pumps had the same issues found for the morning power glitch. I have reset the Kobelco, CP1 pump cart, aux carts, XBM turbopump, and the VPW vacuum ovens. Same procedure as above. Attached is a picture of the CP1 pump cart status and the XBM turbostation as found after the power glitch.

Images attached to this report

H1 CDS - h1sush12 recovered with an extended IO Chassis down time.

david.barker@ligo.org — Sat, 30 May 2026 16:25:38 -0700

Author: david.barker@ligo.org

Report ID: 90398

This morning we tried a power cycle of both the computer and the IO Chassis, with the chassis down for about 40 seconds. This did not bring the 3rd Adnaco BP back so we replaced it.

This afternoon we tried a 4 minute power down of the IO Chassis, and when the computer came up it saw all the cards. So perhaps the backplane removed from the IO Chassis this morning is good.

H1 AOS - Comment to Its deja vue all over again, same issues as before.

david.barker@ligo.org — Sat, 30 May 2026 16:14:31 -0700

Author: david.barker@ligo.org

Report ID: 90397

Looks like the PSL Diode Room Beckhoff has gone down this time.

H1 AOS - Its deja vue all over again, same issues as before.

david.barker@ligo.org — Sat, 30 May 2026 15:41:14 -0700

Author: david.barker@ligo.org

Report ID: 90396

As before all front end computers powered down with the exception of cdsh8 and psl0. When we powered them back up all recovered except h1sush12, which has again lost its 3rd Adnaco backplane in its IO Chassis, even though this is a new BP installed this morning.

HWS at end have gone down, check. 9th port on timing master (dts) is down, check. FMCS EPICS is down, check.

this time h1cdrfm's adnaco expansion chassis at the end stations have not gone down though.

H1 CDS - We have lost power for a second time around 14:40. CDS Overview is as before, all front ends down except cdsh8 and psl0

david.barker@ligo.org — Sat, 30 May 2026 14:51:01 -0700

Author: david.barker@ligo.org

Report ID: 90395

Lost power again.

Images attached to this report

H1 CDS - Comment to CDS status as of 12:34

david.barker@ligo.org — Sat, 30 May 2026 14:02:10 -0700

Author: david.barker@ligo.org

Report ID: 90394

Erik went to the DTS, EX and EY:

. Both end station cdsrfm chassis have been turned on.

. Both end station HWS are operational.

. The EY GPS receiver went red for a while, then got position lock and went green. No action was needed.

. DTS timing fanout was powered up. The timing system is now green again.

EDC is now down to 229 disconnected channels, these are:

NCALX, BRS_EX, BRS_EY, MAINS_EX, CHILLER_EX, CHILLER_EY

These will remain off until Monday.

Also the EY WAP is offline, will be fixed on Monday.

Erik is now recovering some FOM wall monitors.

H1 General - Site Power Issue - FAC Recovery

tyler.guidry@ligo.org — Sat, 30 May 2026 13:24:56 -0700

Author: tyler.guidry@ligo.org

Report ID: 90393

Beginning at 9:57a I began receiving alarms for a fire pump run and a few minutes later alarms for end and corner station chilled water pumps. Initially, FAC systems looked ok. After combing FMCS remotely following persistent alarms, end station pumps were alarmed out, and chillers were naturally in run inhibit. Because I could not reset remotely, I went to site to investigate. I observed that both VFD's on the EX CWP were not receiving power. The electrical service at EX in the AHU was not tripped, but the power light was not illuminated. I reset both and they stayed on without issue. Revisiting the VFD's confirmed they were back online. These issues were mirrored at EY, and the solution was the same. Despite the same alarms at the corner, there were no observable issues with the corner chilled water system. Nor were the fire pumps running. Mid stations seem to be insulated from any issues or alarms. As of 12:45p FAC systems have returned to their nominal state. R. McCarthy T. Guidry

H1 CDS - Comment to CDS status as of 12:34

david.barker@ligo.org — Sat, 30 May 2026 12:44:06 -0700

Author: david.barker@ligo.org

Report ID: 90392

We spoke with Patrick and he says all the Beckhoff items in the list can wait till Monday. Ditto HWS.

Erik is working on the h1cdsrfm end-station Adnaco and Timing Master issues. He is on his way to the end stations and H2 building.

H1 CDS - CDS status as of 12:34

david.barker@ligo.org — Sat, 30 May 2026 12:37:04 -0700

Author: david.barker@ligo.org

Report ID: 90391

Here is what we know is not running (in no particular order)

h1cdsrfm (end station adnaco boxes not responding)

ncalex

brs_ex, brs_ey

hws_ex, hws_ey

mains_ex

chiller_ex, chiller_cs

MSR timing master 9th port has no link, missing DTS fanout?

H1 CDS - Comment to Site Power Issue 09:50, all front ends down.

david.barker@ligo.org — Sat, 30 May 2026 12:34:41 -0700

Author: david.barker@ligo.org

Report ID: 90390

Erik's swap of the 3rd Adnaco backplane on h1sush12 fixed the issue, we can now see the 4th ADC and the models are running.

I have untripped all the SWWDs with the exception of BSC2.

DAQ is good.

LHO VE - VAC Recovery After Site Power Issue

jordan.vanosky@ligo.org — Sat, 30 May 2026 12:31:05 -0700

Author: jordan.vanosky@ligo.org

Report ID: 90389

Following the power issue I came out to the site to check on the purge air, pump carts, RGAs, etc.

The Kobelco had an audible alarm, but was still running. Since the interface screen is dead I could not see what the exact alarm was. Drying towers were also not running, though the dewpoint monitor was still reading -75C. I isolated the purge air at the ball valve past the drying towers, then reset both the compressor and the drying towers. I let the system run isolated for ~30 minutes to make sure dewpoint was stable, then opened the line back to the LVEA.

The CP1 turbo was still running, but the solenoid valves on the foreline had closed. I closed the gate valve to the CP volume, and closed the manual o-ring valve on the turbo foreline. Then reset the cart to open the solenoid valves. Once foreline pressure was stable I then opened the foreline o-ring valve and finally opened the CP gate valve. The pressure internal to the cryopump quickly stabilized, and the pressure never got above 1E-7 Torr since the turbo was still spinning. See attached striptool plot (Thanks Gerardo).

Next up was the XBM turbostation which had tripped completely, the turbo/forepumps/and solenoid valves all tripped, so again I closed the gate valve to the XBM and restarted the turbo station. Once the turbo was back to full speed and pressures on either side of the gate valve looked ok, I opened the gate valve.

The three aux carts in use (GV5 annulus/corner rga/HAM6 rga) all had the pumps still running but the solenoid valve had tripped and closed. Pressures were all still ok (<1e-4 Torr) so I reopened the solenoid valves, waited for pressure to drop and stabilize, then set the carts back on the interlocks. RGA trees were isolated from aux carts and were pumped by small ion pump, so no potential backstreaming into RGA volumes.

Finally, I went to the VPW to check on the vacuum ovens. VBOB had no issues, the turbopumps, forepump, and heaters were all running normally. VBOD is vented and was not baking, though the RGA scroll pump had tripped off, turbo was still running. I closed the foreline valve, and restarted the scroll pump and then opened the foreline valve once the foreline pressure was ok. VBOC had a couple issues, the RGA scroll and turbo both tripped off, so I isolated the turbo and restarted the scroll pump first then spun up the turbo and opened back to the RGA tree. The oven heaters had also tripped off. The oven was baking at 150C and the temp had dropped to 130C by the time I arrived, so I reset the heaters and made sure temperature was ramping back up to 150C.

I also verified all of the chamber cleanrooms were still running ok (HAM1/2, HAM3, biergarten, BBSS test stand cleanroom, BSC2 fan bank, and HAM6 cleanroom).

Leaving site now.

Images attached to this report

H1 CDS - Comment to Site Power Issue 09:50, all front ends down.

david.barker@ligo.org — Sat, 30 May 2026 12:07:19 -0700

Author: david.barker@ligo.org

Report ID: 90388

FMCS has been mainly restored.

All the frontends have been power cycled, they all came back except h1sush12.

EDC required a power cycled of h1susauxb13 to get going.

h1sush12 has losts its 3rd Adnaco backplane in its IO Chassis (has the 4th ADC on it). Erik is in the CER replacing this.

Jordan reports this was a strange outage, with a seemingly random scattering of pumps impacted across the site.

We same something similar, most but not all FOMs down, but most workstations rode through.

H1 CDS - Comment to Start of TW0 offload of last 6 months of raw minute trend files to permanent storage

david.barker@ligo.org — Sat, 30 May 2026 10:46:19 -0700

Author: david.barker@ligo.org

Report ID: 90387

I've stopped this due to the power issue.

H1 CDS - Site Power Issue 09:50, all front ends down.

david.barker@ligo.org — Sat, 30 May 2026 10:46:03 -0700

Author: david.barker@ligo.org

Report ID: 90386

We are investigating a power issue on site which took down all the front ends. We are starting the recovery process.

Initially we thought it was contained to the MSR, but the DTS, Mech Room and end stations are showing problems and reboots.

Erik is on his way to the site. Jordan is on site looking at the vacuum system.

H1 CDS - Start of TW0 offload of last 6 months of raw minute trend files to permanent storage

david.barker@ligo.org — Sat, 30 May 2026 09:07:50 -0700

Author: david.barker@ligo.org

Report ID: 90385

WP13772 TWO Offload

Dave

This morning I started the copy of TW0's raw minute files which have accumulated since 09dec2025 from local SSD-RAID to archive spinning media (h1ldasgw0).

As was done for the last offload in December 2025, following the DC0/FW0 consolidation done 18nov2025 by Jonathan, I am again using h1daqtw0 itself to do the copy. Normally the offload is done by the framewriter, which is still the case on the 1-leg.

The old files were frozen at GPS 1464188058 (07:54:00 Sat 30 May 2026 PDT) prior to offload.

NDS0 was restarted at 08:03 with a temporary configuration to serve the past 6 months of data from its temporary location on TW0 while the copy proceeds.

The copy was started on TW0 at 08:54. It usually takes just over a day to complete.

H1 SPI - Comment to 2026-05-26 thru 2026-05-29 SPI Pathfinder Update

peter.fritschel@ligo.org — Sat, 30 May 2026 06:22:56 -0700

Author: peter.fritschel@ligo.org

Report ID: 90384

If it's the stopper nut on the pico-motor, which seems pretty likely, then why not just screw it in further (away from the screw tip), rather than removing it? Seems much easier than removing it, or any of the other solutions suggested above, and in fact the 'using NF picomotor products' sheet says one shouldn't remove the stopper nut. Of course, if you don't actually need the remote actuation, better to just remove the pico's and replace with manual actuators.

LHO General - Ops Day Shift Summary

ryan.short@ligo.org — Fri, 29 May 2026 16:34:09 -0700

Author: ryan.short@ligo.org

Report ID: 90383

TITLE: 05/29 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Today, HAM7 was vented and most bolts removed from doors while beam alignment continued in HAMs 2 and 3. The LVEA remains Laser HAZARD.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
19:29	SAF	Laser HAZARD	LVEA	YES	LVEA is Laser HAZARD	Ongoing
14:41	FAC	Randy	LVEA	-	Craning table to W-bay	14:59
15:24	VAC	Jordan	LVEA	-	Venting HAM7	17:59
15:36	FAC	Kim	LVEA	-	Technical cleaning	18:12
15:40	SAF	Richard O.	Arms	-	Inspecting beam tube enclosure	18:44
15:40	VAC	Randy	LVEA	-	Venting HAM7	17:13
16:43	ISC	Keita	LVEA	Y	HAM2 alignment	19:25
17:11	ISC	Jennie	LVEA	Y	HAM2 alignment	19:24
17:48	SPI	Jeff	Opt Lab	Local	SPI work	18:13
18:47	SEI	Shoshana	H2 PSL	-	CRS builds	19:39
19:35	VAC	Jordan, Randy	LVEA	-	Breaking bolts on HAM7	20:30
20:24	ISC	Keita, Jennie	LVEA	Y	HAM2/3 alignment	23:32
22:30	EPO	Disha +2	LVEA	-	Tour	23:11
22:50	VAC	Jordan	LVEA	-	Checking RGA bakeout	22:56

H1 SPI - 2026-05-26 thru 2026-05-29 SPI Pathfinder Update

jeffrey.kissel@ligo.org — Fri, 29 May 2026 16:22:26 -0700

Author: jeffrey.kissel@ligo.org

Report ID: 90382

J. Kissel, S. Koehlenbeck [remote], J. Wright, M. Simmonds Here, we post an aLOG to cover the whole week's slog, picking up where we we left off at that end of last week (LHO:90332). %%%%%%%%%%%%% Executive Summary: the remaining outstanding issue to solve before instal for the SPI pathfinder is the irregular and intermittent drift in heterodyne efficiency in the SPI's MEAS IFO (item (3) from the list of issues after finishing re-assembly up to D2400107-v5 after ECR E2600106). Importantly, we've seen this issue in the MEAS IFO even with the previous version of the assembly back in Mar 2026. After a week of hard work, we've ruled out just about everything that it could be *except* for flaws in the alignment system of the picomotor-actuated IXM100 mirror mounts which steer the MEAS beam to the MEAS IFO (see D2400107 for the annotated layout). %%%%%%%%%%%%% I spend the rest of the aLOG summarizing what we've ruled out and how. Remember -- thru out all of these studies, the REF IFO remains a rock-solid high efficiency, and the power monitor PDs so the input power on the MEAS and REF is quite stable. And a reminder for those not-so-versed in heterodyne interferometers, the primary metric is the efficiency, defined as eta = [peak-to-peak beat note amplitude] / (2 * beat note mean) (nominally 100% if the mode overlap between two interfered beams is perfect). "Drift" of this efficiency means that -- without Electronics Issues with the IFO MEAS PDs. - Suspected cause: "maybe the bias voltage is drifting?" "Something's going on with the electronic ground because we're only looking at the positive leg?" - RULED OUT: we swapped the REF B PD (which had been measuring a rock-solid, high efficiency from the REF IFO) into the MEAS B PD position, and had it measure the MEAS IFO beam. The drift was measured by the REF B PD as well. This convinces us that "it's on the incoming interfered beam. - PLUS: The bias voltage is supplied by a single circuit for all PDs in the ISIK transceiver system, so the bias-related issues would be common to REF or MEAS PDs. Spurious drive on the the picomotors - Suspected cause: "maybe the ambient electric field in the room is driving the floating pins of the picomotors, pushing the mirrors around?" - RULED OUT: At the start of the week, the picomotor signal chain was hooked up as designed from motor might-mouse to quadrupus to mock feedthru and out a ~6 ft D25 in-air cable that had been used for testing. (a) Just like we'd already done with the PDs, we hooked up ever single picomotor pin to rack power supply ground via a breakout board and clip leads at the end of the in-air cable. Still see drifts. (b) We also tried simply disconnecting all picomotors at their might-mouse connector. Still see drifts. Clipping along the MEAS path into the MEAS IFO - Suspected cause: "If there's some sort of clipping anywhere, you lose efficiency. If it's just barely clipping, the clipper might be moving / breathing with the environment." - RULED OUT: (a)Checked centering on M_M1, M_B4, M_M2, M_B3, and the two MEAS IFO PDs, and can confirm they're either :: On Optics -- offset in yaw by design (but still several beam diameters away from the optic barrel in REFL or TRANS), or :: Well-centered. (b) We'd started the week with the M_M4 and M_M5 mirror mounts and adapters in place (with no dump in either). The beam comfortably goes through the transmission ports of both adapters. But, over the course of the week, as we ruled out "everything else" out, we removed them so now they're off the board. We still see drift. (c) Confirmed that "tight-squeezes" between beam dumps still allow for at least ~1x beam diameter of clearance (on an IR card). Optics' Quality, dust and schmutz - Suspected cause: "If there's a scratch or schmutz on the optic, then maybe as the beam alignment drifts, the optical quality of the reflected beam is intermittently spoiled." - RULED OUT: We replaced all optics in the MEAS path with just-as-good, same production/coating run, equally class-A cleaned, high quality mirrors. Still see drifts. Beam quality and Optical Mode-shape - Suspected cause: "We haven't found anything, so let's look at the beam shape on a profiler. This should be the definitive answer." - RULED OUT: We removed IFO_MEAS_B, and projected the beam on to a WinCam beam profiler head, and read it's data out in the WinCam software. We looked at the beam both with a very slow heterodyne beat-note of 250 mHz, and the nominal 4096 Hz (adjusting the modulation frequency at our commercial RF source's digital interface). (a) With the MEAS IFO's alignment just tuned up, Compared mode shape and alignment during episodes of high and low efficiency, and we see nothing but excellent beam shape. (In the slow-beat-note-configuration) the only difference in profile results is the expected lower intensity when the efficiency was low. (b) We deliberately misaligned the REF and MEAS beams going into the MEAS IFO such that both beams still visible on the WinCam profile, but not interfering. No movement of beams, no mode shape change, no beam diameter change, nothing that would cause the efficiency drift. Polarization - Suspected cause: "The last thing that it could be if it's not mode shape / quality / alignment is polarization drift..." - RULED OUT: With the same IFO_MEAS_B beam, we inserted a polarizing beam splitter and monitored the s-pol power in the reflected port. S-pol (max) power (at peaks of beat note) is stable at ~10-15 [microWatt] during periods high and low efficiency. The designed p-pol light at IFO is at the 5-10 [milliWatt] level, so the extinction ratio is awesome. And we still see drifts. This also rules out, e.g. the nightmare scenario that the optics' mount PEEK set screw -- only on the MEAS path optics -- are cranked on the optic so hard that is causes birefringence. - PLUS: if there was a board-level polarization drift, the REF IFO would also be seeing this same drift. Optical Power fluctuations (Sanity Check) - Suspected cause: "I know you don't see any drift in the REF IFO, but ... is the input power drifting?" - RULED OUT: (a) The REF IFO beam samples the same beams as the MEAS IFO, and (b) Yes, we've had the power monitor PDs up on the o-cope for days, and we see no obvious or reproducible correlation. RF Modulation Modulation power fluctuations (Sanity Check) - Suspected cause: "I know you don't see any drift in the REF IFO, but ... did you check the RF electronics?" - RULED OUT: Yup, we've had the RF power monitor outputs of the laser prep chassis on the scope most of the time, and these are rock-solid and at the expected level. Environment (Insanity Check) - Suspected Cause: "The only thing that intermittently drifts on the minutes time-scales you're seeing is things like air currents and thermal effects." - RULED OUT: We tried SO MANY different combinations of (a) Clean room Lights ON/OFF (b) Room Lights ON/OFF (c) Clean room Fans ON/OFF (d) People in/out of clean room (e) People in different positions in the clean room and none of these showed obvious or reproducible correlation. Conclusion -- It's gotta be the mechanical assembly of the picomotors in the IXM100 mounts. The picomotor-actuated assembly process was documented in LHO:87497 following the assembly procedure E2500163. [1] The most accurate mechanical drawing we have the IXM mount itself D1100362 [2] The vendor drawings of the picomotor E1000197 [3] The most accurate assembly of a pico-actuated IXM mounts D1500494 and D2100433 [4] The SPI's drawings for its IXM mounts D2400144 and D2400145 Looking at the assemblies: - We're worried that the pico-motor "stopper nut" is pushing the movable-mounting plate (item 1 in [1]), rather than the pico-motor's ball bearing. And somehow this poor kinematic connection is drifting and slipping with the environment or something. - The v-groove of the item 7 in [1] carbide plate faces toward the pitch actuator, and away from the yaw actuator. While this is the right thing to do to prevent over constraint -- because the same part is used in both actuator interfaces, the ball of the pitch actuator (be it manual- or pico- driven) will sit "deeper" in longitudinal than the yaw actuator. The yaw actuators' stopper nuts all easily clear the movable mounting plate, but the pitch actuators do not. - The manually driven IXM100s show there's no issue, given that the cupped 8-100 alignment screw clears the carbide plate holes in the moveable optic-mounting plate. ACTIONS FOR NEXT WEEK We're at our wits end, and considering just ax'ing the picomotor actuation on M_B4 and M_M2. In fact, we've already replaced the mount of M_M2 with a manually driven IXM100, and may do so for M_B4 if we find enough clean IXM100 mounts. However, we've got some ideas to fix the problem and still have remote actuation: - Place a washer between the carbide plate and the front plate. - Remove the stopper nut. - Mill away parts of the front plate. - Get a thicker carbide plate. - Use only one pico-motor per holder. Pictures and further commentary to come in due time.ISC, SEI, SPI, SQZ

LHO VE - HAM7 Vented, Doors Prepped for Removal

jordan.vanosky@ligo.org — Fri, 29 May 2026 14:17:14 -0700

Author: jordan.vanosky@ligo.org

Report ID: 90381

Jordan, Randy

HAM7 and the relay tube were vented this morning following venting procedures E2300169 and M1300464. RV1 remained closed along with FCV1 and FCV2, FC-A section remains under vacuum.

Purge air particle counts were zeros, and the measured dewpoint at the HAM7 point of entry was -41.7C. Chamber was vented in ~2 hours to 780 torr, then the chamber was blown down to atmosphere ~762 torr.

Annulus ion pump was isolated, powered off and the annulus volume was vented using dry nitrogen.

After the chamber and annulus were vented, I wiped down the door flanges with IPA wipes, then Randy and I removed all but four bolts from the -Y door, +X door, and the 2x 12"CF blanks on the +Y door to be used for ISI access.

Will close WP 13283 once doors are removed next week.

Images attached to this report

H1 TCS - EY ALS ingoing and return beam measurements

madison.simmonds@ligo.org — Fri, 29 May 2026 12:19:10 -0700

Author: madison.simmonds@ligo.org

Report ID: 90380

Madi, Camilla, TJ. Repeating work at EX: 90370

Ingoing ALS beam measured between L6 and L7. Beam shape is better than at EX but still has strange astigmatic artefact.

Return beam arguably worse than at EX. Demonstrating the same lobed behaviour, with an overall 'peanut' shape.

Nanoscan head was tilted 45deg at each measurement point, to get comprehensive view of the beam. Both sets of measurements attached.

Pellicle beamsplitter has been left on table at EY.

Images attached to this report

H1 TCS - EX ALS ingoing and return beam measurements

madison.simmonds@ligo.org — Fri, 29 May 2026 10:24:53 -0700

Author: madison.simmonds@ligo.org

Report ID: 90370

Madi, Camilla, TJ

Recently been taking measurements of the ALS beam at EX, initially to observe the beam as it returns from vacuum. This was done using a Pellicle beamsplitter placed in the path of the ALS beam between the PBS and the LPM, which picked off the return beam for observation. Images from this measurement are attached. It was observed that the return beam was elliptical in shape, with two intensity peaks.
The input beam was also re-measured (previous measurements recorded here). It was seen that even the input ALS beam is elliptical in shape, and as it gets closer to the PBS, a lobed intensity pattern begins to appear. Considering the return beam is also elliptical with two lobes in the intensity pattern, the effects of the in-vacuum system are unable to be separated from the input beam characteristics, and limits our ability to use the ALS beam as a diagnostic tool for the in-vacuum path.

Also concerned for the performance of the ALS, that that the ALS beam is elliptical before going into the vacuum system. Potential future task will be to find out where the beam gains this ellipticity and correct it.

Images attached to this report

Non-image files attached to this report

ALSEXbeamprofilemeasurements.pdf

LHO General - Ops Day Shift Start

ryan.short@ligo.org — Fri, 29 May 2026 07:37:59 -0700

Author: ryan.short@ligo.org

Report ID: 90378

TITLE: 05/29 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: 17mph Gusts, 13mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.29 μm/s
QUICK SUMMARY: High winds last night that trigered some dust alarms that have since cleared. More HAM2 alignment work today in Laser HAZARD.

H1 IOO - IMC and IM2 alignment (Jennie, Elenna, Rahul, Keita)

keita.kawabe@ligo.org — Thu, 28 May 2026 23:24:30 -0700

Author: keita.kawabe@ligo.org

Report ID: 90377

https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=90343

As per the plan in the above alog, we did the following for IMC and IM alignment.

Rotated JM3 in negative PIT to center the beam on MC2 in YAW (i.e. the input beam comes close enough to the nominal MC2-MC1 line measured at the location we chose in HAM3). The beam height was good.
Rotated MC2 to bring the beam back to the center on MC3 (i.e. MC2-MC3 line comes close enough to the nominal line measured at the location we chose in HAM2). The height was good.
The beam was already flashing, MC2_TRANS_SUM was already good enough according to Elenna so we didn't bother to turn MC1 and MC3, even though we could have refined further.
The beam spot on the IFI output baffle was very low, so we made a big change to IM2 in PIT. It looked good in YAW but we steered IM2 in YAW to make the beam slightly move to +X direction on the IFI output baffle because so we don't have to do too much YAW for IM3.
We started moving IM3 but didn't finish.

As for clipping, before making IM changes, I installed an iris between IM3 and IM4 to see if the beam from PRM was retroreflecting.

It was not that useful for the intended purpose as I couldn't tell if the IFO refl beam is actually retroreflecting. If anything it looked off in PIT.but it was very hard to tell any difference for YAW even when we made +-300urad changes in PRM in YAW.
However, I noticed that -100urad on PRM YAW makes the IFO refl beam clipping better on IFI input baffle, and -300urad made it disappear. +X side of the IFI input baffle. However, this also resulted in a clipping of the IFO refl beam on the IFO refl baffle in +Y edge. We'll see how this goes after we're done with the IM2 alignment we did today.
Clipping of the IFO refl beam on the IFI input baffle doesn't look like a ghost beam. I used an IR sensitive camera and it was a bright beam.

Numbers and pictures will follow.

Will continue doing the IM3 and IM4 alignment tomorrow.

IOO, ISC

LHO VE - Comment to CP1 Soft Regeneration Update

gerardo.moreno@ligo.org — Thu, 28 May 2026 19:17:01 -0700

Author: gerardo.moreno@ligo.org

Report ID: 90376

CP1 pumpdown continues, no issues to report. However, we had the aux-cart connected to the GV5 annulus trip, but we don't know how it happened, we noted only one tiny slithery critter around the area.

Attached is a plot of the total pumpdown.

Images attached to this report

H1 PEM - Dust: Dust Monitor 10 on the rise

ibrahim.abouelfettouh@ligo.org — Thu, 28 May 2026 18:45:21 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 90375

Just noticed DM 10 has been steadly going up for last 6 hours. So has the wind - could be an unpropped door? Just adding it here for log. Screenshot attached.

PEM

Images attached to this report

H1 SUS - BBSS QOSEMs Installed and Centering 50% Done

ibrahim.abouelfettouh@ligo.org — Thu, 28 May 2026 18:16:35 -0700

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 90374

Ibrahim, Oli, Betsy

Today, we confirmed the BBSS Pointing with an oplev set-up using the M2 BOSEMs while the M1 BOSEMs were still on.

Then, we switched to cabling to prep for the QOSEM install. We installed the QOSEM flags and checked using the M2 BOSEMs and the OPLEV set-up that the pointing was unchanged. Thankfully, it remained the same.

Finally, we installed the QOSEMs onto the flags and began centering. We followed the procedure Oli and I wrote with Thomas' guidance on how to center QOSEMs - E2600219.

Before the end of the day, we were able to center:

the QOSEM about SUM counts, confirming that the LED is totally on the lens.
The QOSEM in the X direction, confirming that the light is hitting the center of the lens along the axis of the flag (in-out).

We will return to it on Monday to finish centering.

The QOSEMs were placed as followed (by SN):

F1 - S2600012

F2 - S2600009

F3 - S2600013

LF - S2600008

RT - S2600011

SD - S2600010

Attached is a sketch confirmation of our electronics for reference.

SUS

Images attached to this report

LHO General - Ops Day Shift Summary

ryan.short@ligo.org — Thu, 28 May 2026 16:32:20 -0700

Author: ryan.short@ligo.org

Report ID: 90373

TITLE: 05/28 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: The LVEA was transitioned back to Laser HAZARD for more alignment in HAM2, work continued on the BBSS to switch it over to the new electronics setup, and prep began to open HAM7 among many other tasks done today.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:36	FAC	Randy	LVEA	-	HAM7 cleaning	14:47
14:56	FAC	Kim	LVEA	-	Technical cleaning	18:10
15:15	SUS	Betsy	LVEA	-	Unplugging BBSS electronics	15:29
15:24	AOS	Corey	Opt Lab	-	Dropping off parts	16:08
15:33	VAC	Travis	MX, EX	-	Finish checking turbopumps	15:52
15:50	AOS	Mitch, Randy, Corey	LVEA	-	Getting baffles from BSC2	16:29
16:08	VAC	Jordan	LVEA	-	Corner RGA scans	16:50
16:16	SUS	Fil	LVEA	-	Moving BBSS cables near HAM3	17:20
16:23	VAC	Travis	LVEA	-	Checking CP1 pump	16:25
16:27	TCS	Camilla	EX	-	Retrieving camera	16:49
16:33	SPI	Jeff	Opt Lab	Local	SPI alignment	19:27
16:41	SUS	Ibrahim, Oli	LVEA	-	BBSS electronics	17:20
16:55	FAC	Randy	LVEA	-	Craning railings on BSC2 platform	17:48
16:57	SPI	Jennie, Madi	Opt Lab	Local	SPI alignment	17:54
17:20	SUS	Ibrahim, Oli	LVEA	-	BBSS work	19:09
17:26	SEI	Jim, Shoshana	H2 PSL	-	CRS building	19:18
17:37	IAS	Jason	LVEA	-	Grabbing FARO laptop	18:07
17:53	SUS	Betsy	LVEA	-	BBSS work	18:52
18:11	FAC	Kim	EX	-	Technical cleaning	18:54
18:39	SPI	Jennie, Madi	Opt Lab	Local	SPI alignment	18:57
19:10	SAF	Keita	LVEA	YES	Transition to HAZARD	19:18
19:29	ISC	Keita	LVEA	Y	HAM2 beam alignment	Ongoing
19:29	SAF	Laser HAZARD	LVEA	YES	LVEA is Laser HAZARD	Ongoing
19:31	ISC	Rahul	LVEA	Y	HAM2 beam alignment	23:29
19:47	ISC	Jennie	LVEA	Y	HAM2 beam alignment	Ongoing
20:14	VAC	Jordan	LVEA	-	Restart corner RGA bakeout	20:23
20:19	FAC	Randy	LVEA	-	Looking for pallets	21:19
20:24	SPI	Jeff	Opt Lab	Local	SPI alignment	Ongoing
20:29	SUS	Oli	LVEA/CER	-	QOSEM cabling/install	Ongoing
20:46	SEI	Jim, Shoshana	H2 PSL	-	CRS building	21:44
20:48	SUS	Betsy	LVEA	-	BBSS work	Ongoing
20:57	SPI	Camilla	Opt Lab	-	SPI optic cleaning	22:06
20:59	SUS	Ibrahim	LVEA	-	BBSS work	Ongoing
21:16	SEI	Mitch	LVEA	-	Dropping off parts	21:25
21:17	VAC	Jordan	LVEA/CER	-	Prep HAM7 electronics for vent	21:42
22:31	TCS	Camilla, Gerardo, Jordan	Prep Lab	-	Building CHETA viewports	Ongoing
22:53	VAC	Travis	MY	-	Cutting insulation	Ongoing
23:11	SEI	Jim	LVEA	-	BBSS work	Ongoing

LHO VE - Comment to Prep for HAM7 Vent, High Voltage Disabled

travis.sadecki@ligo.org — Thu, 28 May 2026 15:33:01 -0700

Author: travis.sadecki@ligo.org

Report ID: 90372

Images attached to this report

LHO VE - Prep for HAM7 Vent, High Voltage Disabled

jordan.vanosky@ligo.org — Thu, 28 May 2026 15:29:07 -0700

Author: jordan.vanosky@ligo.org

Report ID: 90371

Jordan, Travis

To prep for the HAM7 vent we followed the procedure M1300464 to disable the in vacuum high voltage sources and heating elements.

SQZ PZT high voltage
SQZ picomotors
SQZ OPO TEC
The HAM7 pressure interlock box was also powered off, this is not yet in the M1300464 procedure

H1 IOO - Comment to Beam positions in HAM2 and some thinking (Rahul, Elenna, Keita)

keita.kawabe@ligo.org — Thu, 28 May 2026 11:25:02 -0700

Author: keita.kawabe@ligo.org

Report ID: 90336

This is the beam position measurements for MC2 and MC3.

Note: In D0901099-V2 on page 9, it looks as if MC2 HR surface is supposed to be rotated by 0.231 degrees clockwise seen from the top.

I don't think that makes sense unless the ISI table itself is supposed to be rotated 0.231 degrees counter-clockwise because the IMC is an isosceles triangle, MC1-MC3 line is parallel to Y axis and MC2 Y coordinate is the mean of MC1 and MC3 Y coordinate according to the global coordinates of MC1, MC2 and MC3 (E1100494-V4, E1100494-V6).

I assume that the ISI tables aren't nominally rotated around local Z axis.

	Global X	Global Y	Global Z
MC1	-20,072.0	255.0	-97.3
MC2	-3833.1	487.5	-87.3
MC3	-20,072.0	720.0	-97.3

Images attached to this report

H1 General - Elliptical Baffle Assemblies Removed from Chamber

mitchell.robinson@ligo.org — Thu, 28 May 2026 09:52:58 -0700

Author: mitchell.robinson@ligo.org

Report ID: 90368

Corey, Randy, Mitchell

The two Elliptical Baffle assemblies that were taken down for the cartridge de-install have been removed from chamber. These two baffle assemblies will likely not be used again because of the new Cage baffle assemblies.

LHO VE - Quarterly Functionality Test Performed on EX/MX Turbo Pumps

travis.sadecki@ligo.org — Thu, 28 May 2026 09:45:15 -0700

Author: travis.sadecki@ligo.org

Report ID: 90367

FAMIS tasks 31323 and 31308, WP 13258

Procedure checklist for both stations completed. No issues were identified at this time.

MX: Scroll pump hours: 241.1
Turbo pump hours: 153
Crash bearings: 100%

EX: Scroll pump hours: 7161.4
Turbo pump hours: 1113
Crash bearings: 100%

H1 CDS - IOC container work

david.barker@ligo.org — Thu, 28 May 2026 09:41:03 -0700

Author: david.barker@ligo.org

Report ID: 90366

pt100a:

I cleaned up and standardized its container build area. Required a few restarts of the IOC.

kobe_oiltp:

This had been running on opslogin0 in a tmux session. Today I created a container for this IOC, added it to the cluster and retired the tmux.

Images attached to this report

LHO General - Ops Day Shift Start

ryan.short@ligo.org — Thu, 28 May 2026 07:38:37 -0700

Author: ryan.short@ligo.org

Report ID: 90365

TITLE: 05/28 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: 2mph Gusts, 0mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.29 μm/s
QUICK SUMMARY: Work continues today on the BBSS on the test stand and prep begins at HAM7 for doors to be removed next week. No alarms overnight, temperatures and dust counts looks good.