aLIGO LHO Logbook

H1 General - EY Safety Interlock System

filiberto.clara@ligo.org — Tue, 21 Apr 2026 17:33:48 -0700

Author: filiberto.clara@ligo.org

Report ID: 89968

The EY interlock system was found with both the ALS and PCAL laser enable outputs disabled. Trending the laser enable channels shows channels went offline during upgrades to the H1SEIEY IO Chassis. Both the EK1501-0010 coupler and EL2904 binary output terminals were replaced. The 24V DC power to the Safety Interlock Chassis was moved to a dedicated 24V power supply.

CDS

LHO General - Ops Afternoon Shift Summary

ryan.short@ligo.org — Tue, 21 Apr 2026 16:55:52 -0700

Author: ryan.short@ligo.org

Report ID: 89966

TITLE: 04/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Busy day after taking over from Corey. End-of-day optic alignment trends are attached; only things of note are that MC2 is now MISaligned after the Guardian restart today.

Work on BSC2 continued with HEPI actuators and walking plates
TCSX water lines on the optical table started to be replaced
Guardian computer upgraded to Debian 13
- When nodes came back online, this turned BS OpLev damping on, so the suspension was erroneously moving a bit for the afternoon (outputs turned off @ 23:18 to fix)
Laser interlock chassis at EY was worked on, see alog89965 for some details
- This brought the site interlock down for a while; I've recovered the PSL but other lasers remain off until they're needed again
Turbopump on CP1 installed, see alog89967

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
17:38	CAL	Tony, Marc	PCal Lab	-	Looking for parts	17:52
17:38	TCS	TJ	LVEA	-	TCSX expansion joint	18:05
18:10	IAS	Ryan C	LVEA	-	FARO in West bay	19:11
18:20	IAS	Jason	LVEA	-	FARO in West bay	19:11
18:28	CAL	Tony, Fil, Marc	EY	-	PCal chassis troubleshooting	18:51
18:35	FAC	Randy	LVEA	-	Pictures in mega cleanroom	18:43
19:26	FAC	Randy	LVEA	-	Prep for BSC2 platform craning	19:47
19:29	PEM	Ryan C	CER	-	Testing dust monitor	19:39
19:52	EE	Fil, Marc	EY	-	PCal chassis/interlock work	23:11
20:03	SEI	Jim, Randy	LVEA	-	Craning BSC2 walking plates	21:30
20:05	PEM	Ryan C	CER	-	Swapping dust monitors	20:12
20:41	IAS	Jason, Ryan C	LVEA	-	FARO in West bay	22:41
20:43	TCS	TJ	LVEA	-	Prep for TCSX table line swaps	20:58
20:58	CDS	Dave	EY	-	Chassis power supply swap	22:08
21:04	VAC	Travis, Jordan	LVEA	-	Craning BSC2 walking plates	21:23
21:21	CDS	Erik	CR	-	Powering off h1iopiscey	21:21
21:59	TCS	TJ	LVEA	-	TCSX table water line replacements	23:44
22:09	SEI	Jim, Mitch	LVEA	-	BSC2 HEPI actuators	23:26
22:14	TCS	Camilla	LVEA	-	TCSX table water line replacements	23:51
22:35	CDS	Dave	EX	-	Checking power supplies	23:08
22:51	IAS	Jason, Ryan C	FCES	-	Grabbing equipment	23:24
23:11	EE	Fil, Marc	LVEA/OptLab	-	Inventory	00:11
23:32	PEM	Ryan C	CER	-	Dropping off dust monitors	23:33
23:34	VAC	Jordan	LVEA	-	Pictures of CP1	23:40
23:42	CAL	Tony	EY	-	Bringing PCal back up	01:42

Images attached to this report

LHO VE - Installation of Turbopump on CP1

jordan.vanosky@ligo.org — Tue, 21 Apr 2026 16:47:38 -0700

Author: jordan.vanosky@ligo.org

Report ID: 89967

In prep for the C1 regen, we installed the SS500 turbopump on the +X port of CP1, along with a full range gauge and roughing port. This replaced an old Edwards turbopump assembly with the new pump which is compatible with the SS500 cart.

Additionally, since we will not be venting the cryopump to atmosphere during the regen, we can not remove the old CETEC valve and replace with a new VAT valve. So we added a 12" spool on the CETEC valve and then the new redundant 10" VAT gate valve. Once the regen procedure is complete the CETEC valve will remain open and isolation will occur using the new VAT valve.

All new joints were helium leak checked, and no leaks found above the leak detector background of ~4.7E-10 Torr-l/s.

Images attached to this report

H1 CDS - CDS Maintenance Summary: Tuesday 21st April 2026

david.barker@ligo.org — Tue, 21 Apr 2026 16:15:40 -0700

Author: david.barker@ligo.org

Report ID: 89965

WP13187 restart h1ioplsc0 to fix timing issue.

Dave:

At 09:55 h1ioplsc0 (and therefore all models on h1lsc0) was restarted to see if this would clear up the recent spate of IOP timing glitches seen in the past week. So far, so good.

WP13180 h1susauxb2h34 model, add LO1,2 voltage monitors

Jeff, Oli, Erik, Dave:

A new h1susuaxb2h34 model was installed which reads the newly installed 9th ADC for LO1,2 voltage monitor signals. A DAQ restart was required.

New h1spih23 model

Jeff, Dave:

We installed a new h1spih23 model which added 4 slow channels, REF/MEAS CONSCALE for A/B. A DAQ restart was required.

WP13186 h1guardian1 upgrade to Debian 13

TJ, Erik:

h1guardian1 was upgraded to Debian13. This was a from-scratch install using new boot drives. Puppet did a lot of the configuration but some hand editing was also needed.

DAQ Restart:

Erik, Dave:

The DAQ was restarted for the two model changes above.

FW0 spontaneously restarted when FW1 had just got going.

NDS1 restarted at the time h1guadian1 was coming up, we assume that this was caused by a guardian NDS query storm.

FW2 has been down since 02:34 this morning and stopped updating around 05:02. At the time of the DAQ restart we found FW2 running again without no intervention. Following the DAQ restart FW2 died completely. I restarted rts-daqd_rs by hand, it kinda worked but seemed to be a whole full frame behind. So I stopped it for now.

WP13190 EY +24V Power Work. WP13181 PCALY recovery

Erik, Marc, Fil, Tony, Dripta, Richard, Dave:

The cause of the PCALY trip during IO Chassis upgrades Thursday 9th April was tracked to a shared +24VDC power supply between h1seiey and the laser-interlock-chassis.

Fil and Marc moved the interlock power from this shared power supply to a safety-system PS.

This left two remaining issues with EY +24VDC power: h1iscey was not on the correct PS and the SEI-C1 was still supplying the BRS beckhoff mini-terminals.

We took care of the first item. Marc ran a long 24V power cable from the back of h1iscey IO Chassis to the SEI-C1 power strip (mirroring what was done at EX).

We recorded the current draw on all the power supplies before and after the change, and attempted to measure the current surge when h1iscey was powered up.

Here are the +24VDC currents recorded

+24VDC Power Supply	Powers:	Current Before	Current After	Power-On Current Surge
SUS-TC1,2	SUSEY, SUSAUXEY	5.0A	-	-
ISC-YC1, TCS-YC1	Beckhoff -[ISCEY]	9.0A	6.0A	-
SEI-YC1	SEIEY +[ISCEY]	3.2A	5.0A	6.0A (+1 A)

Note that the interlock had already been removed from SEI-YC1 at this time.

This just leaves the BRS Beckhoff terminals incorrectly attached to SEI-YC1, but their current draw sould be negligible.

Here are the EX current values for completeness.

+24VDC Power Supply	Powers:	Current
SUS-C2	SUSEX, SUSAUXEX	5.5A
ISC-C1	Beckhoff	5.0A
SEI-C1	SEIEX, ISCEX	6.0A

H1 CDS - Comment to h1guardian1 machine down for OS upgrade

erik.vonreis@ligo.org — Tue, 21 Apr 2026 13:00:07 -0700

Author: erik.vonreis@ligo.org

Report ID: 89964

Upgrade to debian 13 is completed. Nodes are running, communicating via epics and NDS and controllable from the workstations. Some more testing is needed of git archiving etc.

H1 TCS - TCSX supply line expansion joint OK

thomas.shaffer@ligo.org — Tue, 21 Apr 2026 11:37:45 -0700

Author: thomas.shaffer@ligo.org

Report ID: 89963

Randy T., Camilla C., TJ S.

After the chiller was found tripped off and water was found in the plastic "leak containment apparatus" last week (alog89931), we expected to have to replace the expansion joint as we did in January 2024 (alog75657). Turns out, the expansion joint is okay but the fittings have loosened themselves overtime not just on this line but some of the others as well. More details below.

Today when Randy went to go swap the joint out for a used spare, he noticed that the fittings were very loose, not only on the TCSX supply line, but on a few others. He re-tightened all fittings and we decided to test it out slowly with water. Camilla tried to turn on the chiller, but it would shut itself off saying "low flow". She and I then closed the 3way valve in back which makes the chiller run in a closed loop within the chiller. This worked to get it to run. We then slowly opened that valve to slowly allow water to start flowing down the supply line. Randy was waiting and watching at the joint and never saw any water leaking out during the ~5 min test.

At this point we think that the water just leaked out of the loose fittings when the quick connect was disconnected last week. The updated chiller settings most likely helped and turned off the chiller before the pressure reached levels that could cause damage to the system. We will add checking the tightness to the quarterly pipe check FAMIS task.

Next steps - start on replacing the TCSX table flex lines, and work on making a unistrut cage around the quick connects to avoid bumps in the future.

LHO General - Tues DAY Ops Summary

corey.gray@ligo.org — Tue, 21 Apr 2026 10:39:24 -0700

Author: corey.gray@ligo.org

Report ID: 89958

TITLE: 04/21 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

Covering the morning Ops shift & handing off to RyanS.
LOG:

1431-1553 Technical cleaning @lvea (nellie.kim)
- 1553-1703 kim will head to @ex
- 1553-1630 nellie @my
1500-1604 Property inventory checks in livea & optics lab (christina)
1547-1552 Checking to see if FARO did an auto-power-up this morning (ryanc)
1557-1629 cp1 turbo (new) leak checking (jordan, gerardo)
1615-1645 3ifo checks in lvea & then out-bldgs (tyler)
1615 FAMIS checks (chris)
1619 FARO procedure tests in northbay (jason.ryanC)
1628-1645 pipe bridge, tcsx (tj.randy)
- 1645 TCSy chiller turned OFF (tj)
- 1645 randy swapping out tcsx expansion joint on piping platform
1628 Pcal lab grabbing parts for EY (tony)
- Went to EY after and was done at EY at 1735.
1629-1703 EY annulus pump check (jordan.gerardo)
1645 Guardian server work (WP13186) begins with TJ having me taking SEI nodes to desired states (mainly ISI DAMPED HEPI OFFLINE)
- Eric & TJ beginning guardian server work.
- 1708 Connection error for many/all guardian nodes
1655 h1ioplsc0 restart to try and fix timing errors (dave, W13187); will do a daq restart around 1130.
1703 hepi actuator stuff @bsc2 (mitch,jim)
1717-1733 return to cp1 turbo (new) leak checking (jordan, gerardo)
1720 EY property inventory (fil)
1724 Flushing TCSx system test (camilla, randy)
1729 Ibrahim looking for randy
1739 handing off to RyanS.

LHO VE - Tue CP1 Fill

david.barker@ligo.org — Tue, 21 Apr 2026 10:14:26 -0700

Author: david.barker@ligo.org

Report ID: 89962

Tue Apr 21 10:10:27 2026 INFO: Fill completed in 10min 24secs

Images attached to this report

LHO VE - Comment to HAM1 -Y Door Report

gerardo.moreno@ligo.org — Tue, 21 Apr 2026 10:13:16 -0700

Author: gerardo.moreno@ligo.org

Report ID: 89960

Both aux carts are now removed from the annulus system for HAM1/HAM2. The annulus system is back to nominal, at vacuum and under ion pump management, the main volume for HAM1 is at atmosphere and ready to pump down as soon as it is requested.

Images attached to this report

H1 CDS - h1guardian1 machine down for OS upgrade

david.barker@ligo.org — Tue, 21 Apr 2026 10:12:43 -0700

Author: david.barker@ligo.org

Report ID: 89961

WP13186 TJ, Dave, Erik:

10:07 h1guardian1 powered down for OS upgrade to Debian13.

H1 SQZ - Comment to HAM7 BL2 clipping model

camilla.compton@ligo.org — Tue, 21 Apr 2026 08:48:11 -0700

Author: camilla.compton@ligo.org

Report ID: 89959

The aperture stop installed is D2000339: 0.2" (5mm) diameter.

LHO General - Tues DAY Ops Transition

corey.gray@ligo.org — Tue, 21 Apr 2026 07:27:15 -0700

Author: corey.gray@ligo.org

Report ID: 89957

TITLE: 04/21 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: 0.29 μm/s
QUICK SUMMARY:

BSC2 work continues, CDS work. HAM5 & 6 HEPI has been down overnight due to HEPI pump system issues noted yesterday.

H1 CDS - Workstations updated

erik.vonreis@ligo.org — Tue, 21 Apr 2026 07:20:34 -0700

Author: erik.vonreis@ligo.org

Report ID: 89956

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

H1 ISC - Comment to SRC Gouy Phase measurement (without even locking SRMI)

sheila.dwyer@ligo.org — Mon, 20 Apr 2026 17:13:15 -0700

Author: sheila.dwyer@ligo.org

Report ID: 89955

At the time of this measurement, CO2 heating was central. The CO2 FLIP1MON was 0 and FLIP2MON was 1. Comparing this to the current values and the MEDM that says we are currently using annular heating, I believe this means that these measurements were done with central CO2.

Images attached to this report

H1 TCS - ETMX Ring Heater test, turned up from 1W/segment to 2W/segment.

camilla.compton@ligo.org — Mon, 20 Apr 2026 17:03:51 -0700

Author: camilla.compton@ligo.org

Report ID: 89954

Madi, Camilla

Started ETMX Ring Heater test for HWS testing, turned up from 1W/segment to 2W/segment. Plan to leave until tomorrow.

H1 General - Ops DAY Shift End

oli.patane@ligo.org — Mon, 20 Apr 2026 16:33:53 -0700

Author: oli.patane@ligo.org

Report ID: 89953

TITLE: 04/20 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Some BSC2 and cabling work done today. HAM5 and HAM6 HEPI are going to be down overnight since the HEPI pump is having issues.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
14:40	FAC	Kim, Nellie	LVEA	n	Tech clean	15:32
15:09	FAC	Randy	MidY	n	Rock cleanup on aisle MY	16:10
15:51	FAC	Nellie	HAM Shack	n	Tech clean	16:34
16:01	VAC	Jordan	LVEA	n	CP1 RGA work	16:29
16:44	SEI	Jim	LVEA	n	BSC2 work	17:49
16:57	IAS	Jason	LVEA	n	FARO scoping	17:28
17:20	FAC	Randy	LVEA	n	Just looking at HAM6 cleanroom	18:07
17:21	VAC	Jordan, Gerardo, Travis	LVEA	n	CP1 pump work	18:44
17:34	SEI	Mitchell	LVEA	n	BSC2 work	17:49
19:10	EPO	Jeff, +1	LVEA	n	Tour	20:17
19:47	EE	Fil	MER	n	HAM6 cabling	00:20
20:18	VAC	Travis, Jordan, Gerardo	LVEA	n	CP1 pump work	23:29
20:23	CDS	Dave	EX	n	Reboot BRSX	21:30
20:25	FAC	Randy	LVEA	n	Looking at HAM6 some more	21:43
20:29		Jennie	Optics Lab	n	Looking for laptop	20:40
20:37		Betsy	LVEA	n	Looking at HAM6 with Randy	21:46
20:44	IAS	Jason	LVEA	n	Grabbing FARO parts	20:57
21:10	SEI	Jim	LVEA	n	Talking with Betsy / SEI work	23:28
21:19	TCS	Madi, Camilla, Maya	OpticsLab, LVEA	n	Grabbing parts	21:51
21:30	CDS	Dave	EY	n	Verifying 24V power supply	22:02
21:44	SEI	Mitchell	LVEA	n	BSC2 work	23:28
21:52	TCS	Camilla, Madi, Maya	EX	y(local)	HWS work	23:06
22:12	IAS	Jason, RyanC	LVEA	n	Setting up FARO for tomorrow	22:40
22:22	TCS	TJ	LVEA	n	Draining TCS chiller line	23:19
23:15	SUS	Ibrahim	LVEA	n	BBSS ExpreSS	23:33

H1 TCS - TCSX table drained and most of supply line

thomas.shaffer@ligo.org — Mon, 20 Apr 2026 16:25:21 -0700

Author: thomas.shaffer@ligo.org

Report ID: 89952

In prep for WP13185 to replace the flex lines on the table and the expansion joint, I've drained and vacuumed the TCSX table and then I just used gravity to drain most of the water in the supply line, enough so that the expansion joint is free of water.

H1 CDS - BRS EX computer running again

david.barker@ligo.org — Mon, 20 Apr 2026 16:24:35 -0700

Author: david.barker@ligo.org

Report ID: 89951

WP13182 BRS-EX recovery

Jim, Patrick, Dave

I tried to reboot, but ended up power cycling, h1brsex. Patrick started the code and IOC. Since then it has been attempting to damp over the past few hours.

H1 PSL - PSL 10-Day Trends

ryan.short@ligo.org — Mon, 20 Apr 2026 12:01:08 -0700

sheila.dwyer@ligo.org — Fri, 17 Apr 2026 16:15:52 -0700

Author: sheila.dwyer@ligo.org

Report ID: 89940

The Wensday work that is referenced above is described with helpful detail in 74223

H1 CDS - Comment to ISI Watchdog Trip Plotting Working Again

brian.lantz@ligo.org — Fri, 17 Apr 2026 13:25:42 -0700

Author: brian.lantz@ligo.org

Report ID: 89939

Thanks Dave, those plots are useful diagnostic tools.
I dropped a note in the LLO log so we can be sure this fix gets used at both sites

-Brian

LHO VE - Fri CP1 Fill

david.barker@ligo.org — Fri, 17 Apr 2026 10:31:07 -0700

Author: david.barker@ligo.org

Report ID: 89938

Fri Apr 17 10:10:13 2026 INFO: Fill completed in 10min 9secs

Images attached to this report

H1 CDS - Comment to SUSEY timing/DAC error Thursday 17:32 PDT

david.barker@ligo.org — Fri, 17 Apr 2026 10:08:37 -0700

Author: david.barker@ligo.org

Report ID: 89937

We chose to not restart the IOP. All the ADC/TIM/IPC latched errors cleared with DIAG_RESETs with no problems.

H1 PSL - PSL Status Report Weekly FAMIS

oli.patane@ligo.org — Fri, 17 Apr 2026 09:16:08 -0700

Author: oli.patane@ligo.org

Report ID: 89936

Closes FAMIS#39760, last checked 89840
Laser Status:
NPRO output power is 1.83W
AMP1 output power is 70.39W
AMP2 output power is 137.9W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN

PMC:
It has been locked 6 days, 23 hr 13 minutes
Reflected power = 27.09W
Transmitted power = 104.3W
PowerSum = 131.4W

FSS:
It has been locked for 6 days 23 hr and 13 min
TPD[V] = 0.4872V

ISS:
The diffracted power is around 3.6%
Last saturation event was 1 days 19 hours and 33 minutes ago
Possible Issues:
PMC reflected power is high

H1 CDS - SUSEY timing/DAC error Thursday 17:32 PDT

david.barker@ligo.org — Fri, 17 Apr 2026 09:05:01 -0700

Author: david.barker@ligo.org

Report ID: 89935

h1susey reported a DAC error with both its LIGO-DACs at 17:32 Thursday 16apr2026 PDT. This was caused by a large timing glitch seen on h1iopsusey and h1susetmy at this time, cpu_max of >200uS were seen on both models. This was a recoverable error and DAC0 continues to drive.

The lights were not on at EY at this time, so it does not appear to be related to any in-rack work.

dmesg:

[Thu Apr 16 17:32:21 2026] h1iopsusey: ERROR - LIGO_28AO32(0) DAC error detected, 0x30070086, DAC error counter: 19, is_locked: 1
[Thu Apr 16 17:32:21 2026] h1iopsusey: ERROR - LIGO_28AO32(1) DAC error detected, 0x30070086, DAC error counter: 19, is_locked: 1

Images attached to this report

H1 General - Ops DAY Shift Start

oli.patane@ligo.org — Fri, 17 Apr 2026 07:37:50 -0700

Author: oli.patane@ligo.org

Report ID: 89934

TITLE: 04/17 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, 1mph 3min avg
Primary useism: 0.01 μm/s
Secondary useism: 0.09 μm/s
QUICK SUMMARY: BSC2 ISI work today