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Reports until 17:44, Friday 10 April 2026
LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 17:44, Friday 10 April 2026 (89865)
BSC1 Door Removed

(Travis S., Randy T., Gerardo M.)
Filter cavity tube work
BSC1 +X door was removed today, to be able to accomplish that first we had close the big gap left on by the cleanroom curtains, and do some work with the filter cavity tube.  At the filter cavity tube next to BSC3 connection we removed one side of the bellows, studs were removed, we opted to do that so as not to stretch the door cover, we used aluminum foil to cover both of the holes on the bellow and gate valve before pulling the C3 cover thru.  No issues to report all worked out good.

Door Removal
We attached the engine hoist to the door and loaded the engine hoist with the door.  After some struggle the door was convinced to detach, the outer O-ring left its groove on two spots, top and bottom about 10 inches for each side, we could not get to the top O-ring very hard to reach, no space, so we just managed to unstick it from the door flange and left it out of the groove.  Door was removed without a problem, O-ring protectors were installed, and door covers were set on chamber and door.

Images attached to this report
H1 CDS
david.barker@LIGO.ORG - posted 16:42, Friday 10 April 2026 (89863)
h1hwsey started

TJ, Dave:

TJ would like to get h1hwsey running again. If memory serves, this did not come back after the 06dec2025 site power outage and at the time it was not needed so we did not investigate it further and instead ran the h1hwsetmy_dummy_ioc.service on cdsioc0 (alog88435) to green the EDC.

At 16:00 this afternoon I went to EY and found that h1hwsey's boot disk caddy was not quite seated fully. This computer is not labeled, but can be verified by: tracing the KVM chan3 cable, checking PCIe camera receiver is installed.

I was able to monitor its reboot using the KVM console. I logged in as user controls and was able to ping the EX HWS machine to verify network operation.

Before I left I labeled the machine.

We are currently not running the IOC on h1hwsey and continue to run the dummy IOC on cdsioc0. We will keep this configuration for the weekend, and on Monday we'll stop the dummy IOC and run the real one.

LHO General
ibrahim.abouelfettouh@LIGO.ORG - posted 16:30, Friday 10 April 2026 (89862)
OPS Day Shift Summary

TITLE: 04/10 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

IFO is in IDLE for PLANNED MAINTENANCE

Main tasks today:

LOG:

Start Time System Name Location Lazer_Haz Task Time End
14:36 FAC Kim, Nellie LVEA N Technical cleaning 15:21
14:56 FAC Randy MY, LVEA N Picking up lift 16:41
15:04 IAS Jason LVEA N Turning on FARO 15:17
15:49 FAC Kim, Nellie LVEA N Technical cleaning 16:25
16:08 OPS TJ LVEA N Helping Jim with HAM3 Platforms, looking around 16:58
16:14 SEI Jim LVEA N HAM3 Platforms 16:31
16:28 EE Marc CER N PSL Chassis Work 16:58
17:13   Camilla, Gerardo Optics Lab N Inspecting optics 18:32
17:14 IAS Ryan C, Jason LVEA N FARO 19:40
17:17 FAC Kim LVEA N Technical Cleaning 17:46
18:33 VAC Travis, Gerardo LVEA N Checking out FC Tube 19:37
20:06 FAC Randy LVEA N BSC1 Doors 22:06
20:14 SUS TJ, Elenna Optics Lab N Manta Ray Cabling (BHSS) 21:08
20:31 IAS Jason, Ryan C LVEA N FARO 22:31
20:34 VAC Gerardo, Travis LVEA N Biergarten work 22:45
20:43 EE Marc, Erik CER N Chassis work 21:08
21:09 TCS Madi, TJ EY Local Hartmann 22:45
22:48 CDS Dave EY N Labeling 23:20
23:01 PEM Robert EX N Grounding studies 00:01

 

H1 ISC
ibrahim.abouelfettouh@LIGO.ORG - posted 16:08, Friday 10 April 2026 (89861)
Input and BS Pointing Over Last Two Weeks

In an effort to capture the input and BS alignment in different configurations, I trended back some suspensions and their OpLev and Raw OSEM values for P and Y. Table is below and plot of total timespan is attached.

Date 03/23 04/06 04/07 04/10 (before BSC1 work (1500UTC)) 04/10
Configuration HAM 1,2,3 and BSC 1,2 HEPI Unlocked/Nominal, HAM3 ISI Unlocked/Nominal, GV5 Hard Closed BSC 1,2 HEPI Locked, HAM2 HEPI Unlocked, HAM1/3 HEPI Locked, HAM 3 ISI Locked. GV2 Hard Closed, GV2, GV5 Hard Closed, GV 7 Soft Closed. HAM1 +y Door Still Off Pre-Vent HAM1,2,3 HEPI Locked, BSC 1/2 HEPI Locked, HAM3 ISI Locked HAM1 +y Door ON Corner Vented, HAM1,2,3 HEPI Locked, BSC 1/2 HEPI Locked, HAM3 ISI Locked HAM1 +y Door ON Corner Vented, HAM1,2,3 HEPI Locked, BSC 1/2 HEPI Locked, HAM3 ISI Locked HAM1 +y Door ON, HAM3 Doors Off, BSC1 Door Off
Counts          
BS P Oplev 5.59 -2.59 -5.44 -1.10 -1.1
BS Y Oplev -21.43 -18.84 -18.28 3.52 6.20
MC 1 P -701.17 -693.12 -645 -165.00 -1894.65
MC 1 Y -1386.13 -1352.15 -1359.53 -1381.29 -1224.55
MC 2 P 862.00 732.19 712.30 852.70 1200.76
MC 2 Y -629.41 -405.45 -406.43 -376.60 -998.15
MC 3 P 401.57 372.37 358.45 332.01 -1268.06
MC 3 Y -154.20 -192.72 -202.2 -270.48 -470.61
IM 4 P -2442.81 -2364.65 -2257.6 -2332.12 -2329.7
IM 4 Y -95.51 -73.04 -80.57 -103.24 -105.1
PR 2 P -435.90 -425.54 -395.4 -418.5 -417.83
PR 2 Y -1174.28 -1134.31 -1141.43 -1246.12 -1245.86
Images attached to this report
H1 CDS
david.barker@LIGO.ORG - posted 15:23, Friday 10 April 2026 - last comment - 15:46, Friday 10 April 2026(89859)
CDS Maintenance Summary: Friday 10th April

WP13110 IO Chassis Timing Card Upgrade

Marc, Erik, Dave:

Today we upgraded the IO Chassis Timing Card firmware, sync ribbon cable and RCG (where needed) on:

Front End Timing Card Firmware Sync Ribbon Cable RGC5.5.2 update
h1psl0 yes yes yes
h1susauxh13 no yes no
h1susauxh2 no yes yes
h1seih16 yes yes yes
h1susauxh56 yes yes yes

There were no issues. DCC doc T2600142 was updated.

WP13163 h1isiham6 build against latest blend_switch_library

Jim, Ibrahim, Erik, Dave:

h1isiham6 was updated to use the latest blend switch library, it was the last ISI HAM model to do so.

We combined this with the upgrade of its IO Chassis, and also rebuilt all of h1seih16's models against RCG5.5.2.

A DAQ restart was required.

Move EDC back to h1susauxb13

Erik, Dave:

Back in Dec 2025 at the start of the upgrades we moved the EDC from what was then susauxb123 so it would not be impacted by the BBSS preparation work.

Now that we have completed the BBSS prep, EDC has come home to what is now called h1susauxb13 (sans BS).

This didn't quite go as smoothly as planned and required several restarts of both DAQ legs before it was correct.

The basic squence was:

1. Erik made the puppet changes such that h1edc would not start on h1susauxh56 but would do so on h1susauxb13.

2. Following the upgrade of h1susauxh56's IO Chassis, we powered this up to verify no edc on it.

3. We then hand restarted edc on susauxb13, then started the DAQ 0leg. We had DAQ errors at this point.

4. After a reboot of susauxb13 we found the issue, the daq receiver was not being restarted on DC0, just the daqd service. One DC0 was restarted this way, it had a good edc status. Unfortunately it started not quite in sequence and a clean 0-leg restart later got all the delta-times positive.

5. Restarting the 1leg went a bit better, but NDS1 did not restart cleanly and needed a manual start.

h1susauxh56 is now ready for its BHD upgrade with no impact on EDC trending.

DAQ Restart

Erik, Dave:

As mentioned above this was quite a messy start due to the move of EDC to susauxb13. The EDC INI was also changed to add the non-RGC FEC/SDF channels for the new models started in the past week (spih23, suslo12, susauxh6).

The h1isiham6 ini was also part of this DAQ restart to add the +12 STS GND channels.

 

Comments related to this report
david.barker@LIGO.ORG - 15:46, Friday 10 April 2026 (89860)

Fri10Apr2026
LOC TIME HOSTNAME     MODEL/REBOOT
09:48:14 h1psl0       ***REBOOT***  <<< PSL0 IO Chassis Work, new RGC 
09:49:14 h1psl0       h1ioppsl0   
09:49:27 h1psl0       h1psliss    
09:49:40 h1psl0       h1pslfss    
09:49:53 h1psl0       h1pslpmc    
09:50:06 h1psl0       h1psldbb    
09:53:11 h1susauxb13  ***REBOOT*** <<< SUSAUXB13 IO Chassis Work
09:54:11 h1susauxb13  h1iopsusauxb13
09:54:24 h1susauxb13  h1susauxb13 
09:55:06 h1susauxh2   ***REBOOT*** <<< SUSAUXH2 IO Chassis Work
09:56:07 h1susauxh2   h1iopsusauxh2
09:56:20 h1susauxh2   h1susauxh2  


13:52:09 h1seih16     ***REBOOT*** <<< SEIH16 IO Chassis Work, RGC upgrade, new ISIHAM6 model
13:53:44 h1seih16     h1iopseih16 
13:53:57 h1seih16     h1hpiham1   
13:54:10 h1seih16     h1hpiham6   
13:54:23 h1seih16     h1isiham1   
13:54:36 h1seih16     h1isiham6   
14:06:56 h1susauxh56  ***REBOOT*** <<< SUSAUXH56 IO Chassis Work, EDC removed from front end
14:07:55 h1susauxh56  h1iopsusauxh56
14:08:08 h1susauxh56  h1susauxh56 


14:12:04 h1daqgds0    [DAQ]
14:12:11 h1daqfw0     [DAQ]
14:12:11 h1daqtw0     [DAQ]
14:12:12 h1daqnds0    [DAQ]
14:14:27 h1daqgds0    [DAQ]
14:14:32 h1daqfw0     [DAQ]
14:14:33 h1daqnds0    [DAQ]
14:14:33 h1daqtw0     [DAQ]
14:16:52 h1susauxb13  ***REBOOT***
14:17:51 h1susauxb13  h1iopsusauxb13

14:17:37 h1susauxb13 h1edc[DAQ] <<< EDC restart in its new location
14:18:04 h1susauxb13  h1susauxb13 
14:24:44 h1daqnds0    [DAQ]
14:24:50 h1daqtw0     [DAQ]
14:24:52 h1daqgds0    [DAQ]
14:25:00 h1daqfw0     [DAQ]
14:31:26 h1daqdc1     [DAQ]
14:31:34 h1daqtw1     [DAQ]
14:31:36 h1daqgds1    [DAQ]
14:31:41 h1daqfw1     [DAQ]
14:34:49 h1daqfw1     [DAQ]
14:35:18 h1daqgds1    [DAQ]
14:35:59 h1daqnds1    [DAQ]
14:40:53 h1daqgds0    [DAQ]
14:42:05 h1daqgds0    [DAQ]
14:42:11 h1daqfw0     [DAQ]
14:42:12 h1daqnds0    [DAQ]
14:42:12 h1daqtw0     [DAQ]

 
 

LHO VE
david.barker@LIGO.ORG - posted 10:34, Friday 10 April 2026 (89856)
Fri CP1 Fill

Fri Apr 10 10:08:26 2026 INFO: Fill completed in 8min 23secs

 

Images attached to this report
H1 CDS
david.barker@LIGO.ORG - posted 07:45, Friday 10 April 2026 (89853)
CDS Maintenance Summary: Thursday 9th April 2025

WP13110 IO Chassis Timing Card upgrades

Marc, Erik, Tony, Dave:

We upgraded the Mid and End Station IO Chassis. They all had the TC firmware upgrade and only needed the sync ribbon cable upgrade. All the models were running RCG5.5.2 with the exception of SEI and PEM-MID which were still at RCG5.5.0. These were upgraded by performing a rev-locked build in place with the new RCG. No DAQ restart was needed.

Only issue was h1susauxey did not power completely power down when the systemctl poweroff command was issued and I had to use IPMI to complete the power down.

Status of the IO Chassis upgrade can be found at T2600143

BSC2 SWWD trips and LSC Timing glitch

Late in the afternoon the B2H34 SWWD tripped due to BSC2 work. Because the beam splitter sus is now combined with HAM3,4 I chose to untrip this WD rather than leave it down overnight.

Around this time h1ioplsc0 jumped a timing cycle, most probably due to rack/wiring work. I restarted all the models on h1lsc0 to clear this.

Restart Log:

Thu09Apr2026
LOC TIME HOSTNAME     MODEL/REBOOT
13:45:25 h1susex      ***REBOOT*** <<< EX IO Chasis work
13:45:28 h1seiex      ***REBOOT***
13:45:31 h1iscex      ***REBOOT***
13:45:35 h1susauxex   ***REBOOT***
13:46:34 h1susauxex   h1iopsusauxex
13:46:47 h1susauxex   h1susauxex  
13:47:01 h1susex      h1iopsusex  
13:47:08 h1seiex      h1iopseiex  
13:47:12 h1iscex      h1iopiscex  
13:47:14 h1susex      h1susetmx   
13:47:21 h1seiex      h1hpietmx   
13:47:25 h1iscex      h1pemex     
13:47:27 h1susex      h1sustmsx   
13:47:34 h1seiex      h1isietmx   
13:47:38 h1iscex      h1iscex     
13:47:40 h1susex      h1susetmxpi 
13:47:51 h1iscex      h1calex     
13:48:04 h1iscex      h1alsex     
14:04:08 h1pemmx      ***REBOOT*** <<< MX IO Chassis work
14:05:05 h1pemmx      h1ioppemmx  
14:05:18 h1pemmx      h1pemmx     
14:31:11 h1iscey      ***REBOOT*** <<< EY IO Chassis wor
14:31:13 h1susey      ***REBOOT***
14:31:19 h1seiey      ***REBOOT***
14:31:30 h1susauxey   ***REBOOT***
14:32:29 h1susauxey   h1iopsusauxey
14:32:42 h1susauxey   h1susauxey  
14:32:42 h1susey      h1iopsusey  
14:32:52 h1iscey      h1iopiscey  
14:32:53 h1seiey      h1iopseiey  
14:32:55 h1susey      h1susetmy   
14:33:05 h1iscey      h1pemey     
14:33:06 h1seiey      h1hpietmy   
14:33:08 h1susey      h1sustmsy   
14:33:18 h1iscey      h1iscey     
14:33:19 h1seiey      h1isietmy   
14:33:21 h1susey      h1susetmypi 
14:33:31 h1iscey      h1caley     
14:33:44 h1iscey      h1alsey     
14:42:46 h1pemmy      ***REBOOT*** <<< MY IO Chassis work
14:43:43 h1pemmy      h1ioppemmy  
14:43:56 h1pemmy      h1pemmy     
17:22:46 h1lsc0       h1ioplsc0   <<< Recover LSC0 from timing glitch
17:23:00 h1lsc0       h1lsc       
17:23:14 h1lsc0       h1lscaux    
17:23:28 h1lsc0       h1sqz       
17:23:42 h1lsc0       h1ascsqzfc  
 
 

LHO General
ibrahim.abouelfettouh@LIGO.ORG - posted 07:34, Friday 10 April 2026 (89852)
OPS Day Shift Start

TITLE: 04/10 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: 4mph Gusts, 2mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.14 μm/s 
QUICK SUMMARY:

IFO is in IDLE for MAINTENANCE

BSC2 and HAM3 prep and vacuum work to continue

H1 TCS (ISC, TCS)
vladimir.bossilkov@LIGO.ORG - posted 06:53, Friday 10 April 2026 - last comment - 10:07, Friday 10 April 2026(89851)
ITM only CHETA likely to exacerbate PI issues, particularly for LHO

It dawned on me recently that with the scratched view ports for CHETA, the delay of the CHETA roll out could have a subtle saving grace.
The intended use for IR1 is to heat the ITM with the same power as the absorbed power, so that the ITMs would remain in more or less the same thermal state at all times, making DRMI locking fast and reliable, and removing some of the impact on SRC detuning changing over time as the ITM lenses would evolve less than in O4.
It appears that in the CHETA Design Document, the effects on mode spacing and therefore Parametric Instabilities (PIs) was completely overlooked. Shame, no PI expert in LIGO was consulted, I'm even an author on the cited document in the design document and how we used CHETA like actuators at UWA to mitigate PI.

Very simplistically, rolling out CHETA only for the ITMs (as was the plan for the upcoming IR1) would have two impacts on how the optical mode spacing evolves:

In O4 LHO's QUAD Radii of curvature's operating point has them stuck between two lock-losing PIs, and they haven't managed to demonstrate reliable damping of either. This lead to several periods in O4 where their lock stretches would be repeatedly cut short at around 4 hours.
The implementation of CHETA on ITMs only would have put them closer to their 10.4 kHz PIs as a starting condition, and because the mode spacing would be changing more slowly over time, they would experience the frequency matched condition of PI for longer periods of time. Thus:

I could spend time modelling this but its blindingly obvious once you notice.
CHETA on both ETMs and ITMs would theoretically allow you to start with essentially thermalised mode spacing, allowing you to more reliably side-step PIs.

Comments related to this report
matthewrichard.todd@LIGO.ORG - 10:07, Friday 10 April 2026 (89854)

This interesting, though I am certainly no PI expert. Naively, I am not as alarmed for the 10.4kHz PIs for IR1 because the YARM TMS is already below it in its thermalized state, and I hope that we can change ring heaters successfully before IR1 to match the XARM to that for frequency noise reasons. I understand that this has additional implications on the higher frequency PIs and I have no intuition if this move is the right direction for those (maybe you do).

But just a quick order estimate, the absorptions in the ITMs are estimated to be about double what the ETMs are, and the coupling of beam heating to ETM ROC change is about 75% of that for the ITM, so overall I might estimate 3-4 times less thermalization transient when we have ITM CHETAs (so maybe a total change in LG10 spacing of 80-100Hz or so). I think if we set the ring heaters correctly, we can stay away from the 10.2 and 10.4kHz acoustic modes, but maybe more modeling should be done.

H1 SUS (GRD, ISC)
oli.patane@LIGO.ORG - posted 18:28, Thursday 09 April 2026 (89850)
Fixed issues with JM3 saturating + IMC Guardian change request, ft. The Last Time We Offloaded MC WFS

Jenne, Oli

JM3 is no longer saturating.
During this investigation, we ended up finding the last time that we offloaded MC WFS, so for future reference, the last time we offloaded MCWFS was 2026/03/10 21:51 UTC.

JM3 Saturating
Earlier TJ noticed that JM3 was saturating. I went to take a look and found that the overdamping on JM1 and JM3 that had been done for in-chamber work at the beginning of April (89732) hadn't been undone, so now that the HAM1 doors were on, the damping was just way too much(JM1, JM3). I reverted these damping changes on both JM1 and JM3(JM1, JM3).

However, this didn't stop the saturations on JM3. The LOCK filter bank was sending in large negative numbers that were coming in from WFS DOF3 P and Y. With Jenne's help, we were able to sort of figure out what had happened.

The channel we look at for triggering the IMC WFS is IMC-IMC_TRIGGER_INMON, which is IMC-MC2_TRANS_NSUM_OUT_DQ divided by IMC-PWR_IN_NORM_MON. It seems like for some reason this morning IMC-MC2_TRANS_NSUM_OUT_DQ started going up, probably from noise and light in the LVEA, and ended up triggering the IMC WFS (the value was actually still lower than the trigger threshold of 40 so that's still a mystery though). Anyway, once the WFS were triggered, they were turning off and on over the next 4.5 hours. This caused garbage noise to build up in the DOF integrators, which got sent out to MC1, MC2, MC3, and JM3.
We cleared history on these filter banks, which fixed JM3.

IMC_LOCK Guardian Request
We think that something should be put into the IMC_LOCK guardian so that when we go through MOVE_TO_OFFLINE, something happens to prevent the WFS from turning on, like turning off the DOF inputs. Then when we go through DOWN, we turn the WFS inputs back on. This would prevent the integrators from building up garbage noise like what happened here.

Images attached to this report
H1 General
anthony.sanchez@LIGO.ORG - posted 16:54, Thursday 09 April 2026 (89843)
Thursday Morning Ops Report

TITLE: 04/09 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
HAM3 +Y door is removed
BSC1 door bolts are being broken.

GRB- Short E632727 17:33 UTC  notification (IFO status: Vented .)

Both HAM3 doors are Off. 

I have attached screen shots of all of the SDF Diffs from EX & EY before the CDS team rebooted  IOPs for both End stations after Marc replaced the IOP Ribbon cables.

20:26 UTC EX IOP Restarts 
20:58 UTC EY IOP Restarts 
Started to bring EX back up at 21:12 UTC untripped watchdogs for HEPI & ISI.

Fil is unplugging some IMC cables.

JM3 Looks to have grown in motion over the last few hours for some reason. Oli believes that JM3 is "Over damped" due to the wrong gain not being reverted,  Oli's alog with more detailed coming soon.

BSC2 dust mon counts for the day.
 

Start Time System Name Location Lazer_Haz Task Time End
14:34 FAC Randy , Eric LVEA BSC2 n Working on platforms near  BSC2 & Fly Engine Hoste 15:05
14:34 FCA Nellie & Kim LVEA n Technical cleaning and Supplies 15:17
15:46 FAC Nellie & Kim LVEA N Techincal cleaning & Supplies 17:01
16:15 VAC Randy LVEA N Preparing to break bolts on BSCs 19:15
16:29 VAC Gerardo, Jordan, Travis LVEA HAM3 N Prepping for removing Bolts. Gerardo Still in. 18:50
16:46 VAC Corey LVEA N Prepping to break bolts off of BSCs 18:58
17:23 PSL Jason Mech Rm N Draining PSL Chiller 17:34
17:33 Safety Richard LVEA N Helping with Door removal 17:33
17:48 FAC Tyler & Conel Oil Water tank N Refueling diesel 17:48
17:51 BHSS Elenna, Oli Optics Lab YES Working on BHSS 19:28
18:21 SEI Jim LVEA N Unplugging a few cables 18:41
19:00 FAC Kim LVEA N Getting Supplies. 19:03
19:22 BUSI Kim B. Mids & Ends No Reconnaissance mission for Documents. 21:52
19:38 SUS Corey LVEA BSCs N Breaking Bolts on BSC1 & 2 22:10
19:46 EE Fil CER & LVEA N Cabling in CER & Output Arm 22:46
20:03 SUS Randy LVEA N Breaking Bolts Off BSC1 & 2 22:19
20:28 VAC Gerardo & Jordan LVEA BSC1 N Turning bolts off, Gerardo out early 22:12
20:43 CDS & EE Erik & Marc EX &EY N Replacing Ribbon cable & Rebooting IOPs 22:00
20:49 VAC Travis LVEA N Helping with Bolt removal and supplies. 22:05
20:54 Safety Richard LVEA N Seeking Fil 21:24
20:56 SUS Oli LVEA N Looking for parts 22:31
21:34 BHSS Oli & TJ Optics lab N Working on Manta Ray 23:26
21:35 SEI Jim LVEA N Locking HAM3 23:23
21:57 Tour Elenna & Tour Control RM & Overpass n Giving a tour 21:57
22:21 sus Richard LVEA BSC2 N Setting up camera for Beam Splitter Swap 23:08
22:39 VAC Gerardo, Jordan, Travis LVEA N Checking BSC2 work 23:11

 

Images attached to this report
LHO VE (EPO, PEM, VE)
corey.gray@LIGO.ORG - posted 16:15, Thursday 09 April 2026 - last comment - 17:35, Friday 10 April 2026(89849)
BSC1 +Y Door Bolts Removed + BSC2 Dome Bolts Removed, BUT Had One Galled Dome Bolt!

(Jordan V, Corey G)

In prep for upcoming BBSS Install, "broke" bolts (which is slang for loosened them) on:

BSC1's +Y Door Bolts (mostly) Removed & Accelerometer Cable Disconnected

BSC1's door had all bolts but (4) removed.  Sadly, I removed the bottom (easy ones) bolts first and then when I got to the top bolts they were very hard to loosen because of some sag.  Additionally, their access is horrible with:  a stiffening plate for the chamber right above the rear access to these bolts, then there are cable trays also in the way, and the C3 fabric cover is draped in your face the whole time.  Jordan helped out and we were able to get the last top bolt removed.  We also loosened the (4) bolts 1-turn which is the typical procedure.

There was an accelerometer still cabled up to this door.  I disconnected the cable (labeled "PEM:BSC1_ACC_X") and stuffed the cable into the cable tray above this door.

Time lapse of me removing half the bolts in this LINK (since we only files allowed in alog have to be smaller than 15Mb.)  :(

BSC2's Dome Bolts (mostly) Removed, But Have A Galled Bolt!

BSC2's dome bolts were removed.  4-bolts were left in place (they were loosened and then tightened up a little).  One notable, is there is 1-galled dome bolt.  Jordan and I used the long wrenches to see if we could use more force to help it break loose, but no luck.  We did not try pouring some alcohol on the bolt to help as a lubricant.  The bolt is loose and has about 1-2mm of a gap on it.  So, the pros could try use even longer cheater bars, a saw cutter, or they were also chatting about a tool to cut the nut off.  At any rate, 

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gerardo.moreno@LIGO.ORG - 17:35, Friday 10 April 2026 (89864)VE

(Travis S., Gerardo M.)

Travis brought his portable reciprocating saw and a couple of new blades, this little saw did the job, we were able to make a couple of cuts then used the big wrenches to break the bolt off.  Galled bolt is off!

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LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 15:35, Thursday 09 April 2026 - last comment - 15:49, Thursday 09 April 2026(89846)
HAM3 Doors are Off

(Jordan V., Travis S., Randy T., Corey G., Gerardo M.)

The removal was somewhat cumbersome for both doors, but the doors are off HAM3, on the +Y door both O-rings popped out at the bottom of the chamber, they were easily coaxed back into the O-ring groove, both O-rings were out from 5 to 7 O'clock, both bolt holes at this location have traces of "rust".  The -Y side door was a bit more sticky, it took some time to convince the door to come loose, and we had O-rings out of the groove from 4:30 to 6:15 O'clock, both of them at one point.  They went back into the O-ring groove without a major issue.
Flange protector were installed and both C3 covers, purge is up.

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corey.gray@LIGO.ORG - 15:49, Thursday 09 April 2026 (89848)EPO, VE

I ended up joining the VAC/FAC crew in the middle of their work.  Snapped some additional photos and videos when I could.

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H1 SUS (ISC)
elenna.capote@LIGO.ORG - posted 15:33, Thursday 09 April 2026 - last comment - 11:27, Friday 10 April 2026(89847)
BHSS optics aligned, beam dumps placed

[Oli, Elenna]

Summary: Oli and I finished the alignment of all the optics on the BHSS. We were able to place beamdumps to capture the reflected beams off of the four QPDs.

Oli wrote up a summary of the work from yesterday, 89836, and they noted a mistake in the alignment of the B path. We were able to correct that alignment, so the reflected beam from QPD-T-B-R2 goes to QPD B 1 and the transmitted beam reflects off QPD-T-B-R3 to the QPD B 2. Keep in mind that we are following the naming convention that's currently in D2000405 and the BHSS build document T2100190. We found that we had placed B-R2 one hole wrong yesterday, and once we had corrected this, it was much easier to center the beams on the mirrors and get them to the correct QPDs.

Oli briefly described this issue yesterday, but I want to emphasize again: we struggled to use the D2400130 alignment template to align the mirror called "36-R1". This mirror is a high reflector that steers the beam to a splitter that splits to the on-platform OMCB REFL path, and then off-platform to the LO WFS. Because this mirror is a high reflector, it has black glass clipped to the back, and the screw to hold the clip in place protrudes and interferes with the place the optic is supposed to press against the alignment template. This means we have to slightly rethink the HAM6 table alignment plan slightly. I think, since we have aligned the subsequent beamsplitter to the OMCB REFL path, we can follow these steps:

These steps will vary slightly depending if we only do the phase A install, or we do phase A and B together. If we only do phase A, we will just have to guess the 36-R1 placement for now, because there will be no beam to check it.

We are ready to go for cable routing and butterdish clamping on the BHSS!

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elenna.capote@LIGO.ORG - 11:27, Friday 10 April 2026 (89857)

Forgot to add- we have placed the TRN-T1 mirror on transmission of OMCA according to its location on the diagram, and it is already clocked. However, the transmitted beam is very weak, so we have not been able to check its alignment with the beam. This is the only on-platform OMC transmission optic.

H1 ISC
marc.pirello@LIGO.ORG - posted 10:54, Wednesday 08 April 2026 - last comment - 10:18, Friday 10 April 2026(89822)
IO Chassis Firmware and Sync Cable Upgrade

Per WP13110 we have upgraded the IO chassis listed below.
This link contains the asbuilt for all of the H1 IO Chassis: https://dcc.ligo.org/LIGO-D1301004
This link contains the ECR for the IO Chassis sync cable upgrade: https://dcc.ligo.org/LIGO-E2600069

This link is to the work in progress spreadsheet LHO Front Ends Upgrade Status

Corner:
SUSB2H34 has upgraded firmware and sync
SUSAUXB2H34 has upgraded firmware and sync
SEIH7 has upgraded firmware and sync
OMC0 has upgraded firmware and sync
OAF0 has upgraded firmware and sync
ASC0 has upgraded firmware and sync
LSC0 has upgraded firmware and sync

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david.barker@LIGO.ORG - 16:08, Wednesday 08 April 2026 (89831)

Here is the current IO Chassis upgrade status:

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marc.pirello@LIGO.ORG - 15:17, Thursday 09 April 2026 (89845)

Completed the following upgrades today.  While making rounds I took time to check the Kepco power supplies and found one failed but not tripped, EX-VDD2-U22-RHS Rotor Locked, +/-18V ISC_C1 S1203039.  Will exchange at earliest convience.

EX:
H1SUSAUX_EX already had latest firmware, sync cable upgraded
H1SUS_EX already had latest firmware, sync cable upgraded *
H1ISC_EX already had latest firmware, sync cable upgraded
H1SEI_EX already had latest firmware, sync cable upgraded
* H1SUS_EX has 2 LD32 DAC's without heatsinks.  It also has a 3rd fan installed.

MX:
H1MX already had latest firmware, sync cable upgraded

EY:
H1SUSAUX_EY already had latest firmware, sync cable upgraded
H1SUS_EY already had latest firmware, sync cable upgraded
H1ISC_EY already had latest firmware, sync cable upgraded
H1SEI_EY already had latest firmware, sync cable upgraded

MY:
H1MX already had latest firmware, sync cable upgraded

marc.pirello@LIGO.ORG - 10:18, Friday 10 April 2026 (89855)

Started the day upgrading IO chassis:

Corner:
PSL0 has upgraded firmware and sync
SUSAUXH2 has upgraded firmware and sync
SUSAUXB13 has upgraded firmware and sync
SEIH16 has upgraded firmware and sync
SUSAUXH56 has upgraded firmware and sync

H1 SUS (SUS)
ryan.crouch@LIGO.ORG - posted 14:48, Tuesday 07 April 2026 - last comment - 13:31, Friday 10 April 2026(89809)
OPLEV charge measurements, ETMX, ETMY

We ran the OPLEV charge measurements this afternoon. We had a env / package issue trying to start the script, it was complaining about the scipy sin function, I ended up changing from the default cds env to the aligoNB using "conda activate aligoNB" after doing a pip env search to find which environment had the needed packages, I still had scipy sin issues but they were depreciation warnings. To fix this script we may be to rewrite the scipy parts with numpy. The End Stations SEI configuration was ISI_DAMPED_HEPI_OFFLINE. This was a pretty good measurement unlike a few of the previous ones, I didn't get any saturations on either QUAD and the coherence was pretty good.

ETMY's charge is a little high (above 50 on half of the plots) but it is trending to zero or is mostly static near zero (UR P).

ETMX's charge is high (above 50 on all but 2/8 plots but not quite at 100) and is trending away from zero, increasing. The ETMX_L3_LOCK_BIAS_OFFSET value has been at its "unlocked" value of -8.9 during the break, it flips to ~+6 when we are in full lock.

We are still fully processing and thinking about the results, more to come.

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rahul.kumar@LIGO.ORG - 14:53, Tuesday 07 April 2026 (89811)SUS

Our plan is to it to switch the sign and take another measurement this week (and then once every week now) to see if that is helping ETMX or not. 

Will be posting the bias sign and values once we have settled with one which works.

rahul.kumar@LIGO.ORG - 13:31, Friday 10 April 2026 (89858)

Sheila, Rahul

Since charge for EY is trending down, hence will switch off (digitally) HV for this one.

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