aLIGO LHO Logbook

LHO VE - Comment to Water leak found in Corner Purge Air Compressor Auto Drain Line

gerardo.moreno@ligo.org — Sun, 22 Feb 2026 14:26:21 -0800

Author: gerardo.moreno@ligo.org

Report ID: 89225

(Jordan, Brandon (Rogers Machinery tech), Richard, Betsy, Gerardo)

Purge air update.

Checked the Kobelco unit and the system is running normal, nothing to report. Dryer tower reports a dew point reading of -76.0 °C. I opened the purge air to the LVEA, took an initial dew point measurement at the HAM1 purge port, sorry no photo of reading, but it read -41.2 °C, and after one hour and 30 minutes of purging, a second measurement was taken, dew point reading of -48.2 °C.

Purge admittance valve for HAM1 is open now.

A reminder for others HAM1 has double soft covers for both doors. We were instructed to install the second one on the +Y door.

Note and reminder for others, sometime this week Rogers Machinery technicians are to return to replace the oil pump for the compressor.

Leaving site now.

Images attached to this report

LHO VE - Sun CP1 Fill

david.barker@ligo.org — Sun, 22 Feb 2026 10:21:22 -0800

Author: david.barker@ligo.org

Report ID: 89224

Sun Feb 22 10:10:32 2026 INFO: Fill completed in 10min 28secs

Images attached to this report

LHO VE - Comment to Water leak found in Corner Purge Air Compressor Auto Drain Line

david.barker@ligo.org — Sun, 22 Feb 2026 09:35:11 -0800

Author: david.barker@ligo.org

Report ID: 89223

Here is a trend of the dew point from 17:00 Fri 20th Feb through to 09:00 Sun 22nd Feb.

Images attached to this report

LHO VE - Comment to Water leak found in Corner Purge Air Compressor Auto Drain Line

jordan.vanosky@ligo.org — Sat, 21 Feb 2026 11:52:06 -0800

Author: jordan.vanosky@ligo.org

Report ID: 89222

2/21/26

A tech from Roger's Machinery came out to the the site today to diagnose the issue. It was indeed the ball valve on the aftercooler drain line, the valve body had cracked right through the threads. He swapped the ball valve and cleaned the water from the bottom of the cabinet.

Compressor was restarted, open to the receiving tank and drying towers, but the purge air outlet valve was not opened. No other issues found, the dewpoint at the drying towers dropped quickly (currently at -56C and still dropping).

There is still no purge air going out to the LVEA/HAM1, the compressor/dry air skid will continue to run over the weekend before opening back up to the LVEA purge air line.

Closing WP 13038

Images attached to this report

LHO VE - Sat CP1 Fill

david.barker@ligo.org — Sat, 21 Feb 2026 10:17:54 -0800

Author: david.barker@ligo.org

Report ID: 89221

Sat Feb 21 10:11:00 2026 INFO: Fill completed in 10min 56secs

Images attached to this report

LHO VE - Comment to Water leak found in Corner Purge Air Compressor Auto Drain Line

gerardo.moreno@ligo.org — Fri, 20 Feb 2026 23:09:43 -0800

Author: gerardo.moreno@ligo.org

Report ID: 89220

Kobelco unit

The compressor remains off, the new leak, a coolant leak was found at a ball valve, and it needs to be fixed. We have contacted the vendor and are awaiting on a response.

HAM1 Update

HAM1 remains closed for business until further notice, or a work around can be established.

Caution, watch out for volume on your device, lots of noise present on attached video.

Non-image files attached to this report

CrackedValveTiny.mov

LHO VE - Water leak found in Corner Purge Air Compressor Auto Drain Line

jordan.vanosky@ligo.org — Fri, 20 Feb 2026 17:46:43 -0800

Author: jordan.vanosky@ligo.org

Report ID: 89219

When checking the Kobelco unit this afternoon, I found there was a standing puddle of water (~1/4in deep) on the right side (looking at control screen) of the enclosure. Moving to the back side it was found to be a leak in the aftercooler auto drain line, right at the isolation ball valve. There was a continuous spray of water coming from the threads on the upstream side of the ball valve.

The dewpoint at the drying towers was still -81C, same value as this morning, so it did not cause any issues downstream of the compressed air line. The drained water was simply collecting in the bottom of the enclosure instead of flowing out of the drain line.

There was no in-chamber work happening at HAM1 at the time of discovery so after a phone call with Gerardo, I shut down the compressor unit and isolated the air line between the compressor and the receiving tank. I then closed the purge air inlet valve at the HAM1 chamber.

There is currently no purge air going to the LVEA.

Images attached to this report

H1 IOO - JAC work today summary

jennifer.wright@ligo.org — Fri, 20 Feb 2026 17:26:39 -0800

Author: jennifer.wright@ligo.org

Report ID: 89218

Jennie W, Keita K, Rahul K, Ryan S,

This morning Keita turned the power up to 1 W and the purge air down in order to scan the OMC and measure the modulation index.

We had some work to do to lock the JAC, the cavity wouldn't scan properly when managed by the guardian code.

Ryan and I have looked back at it and think there may be something wrong with the feedback to the PZT. It can't be the PZT itself though, because Keita and I were able to lock on the TRANS PD signal with the dither locking done manually by tuning the PZT offset to find the resonance and then turning on the feedback.

I have enclosed a picture to aid problem solving next week.

We then had problems keeping the IMC locked so Keita had to change the threshold used to check if the cavity is locked down to 2. This was changed at line 133 in ISC_library.py at userapps/h1/isc/guardian/.

trans_pd_lock_threshold = 2

We then managed to do three scans,

one with 45 MHz off, one with both on, and one with 9 MHz off. Detailed analysis in progress.

After turning the power back down Keita and Rahul swapped the mirror we currently have in front of the TRANS PD, with the uncoated laser window that is meant to be there (JACT_BS1).

They had to top gun and swab it to remove two dust particles first.

This replacement means the power to the PD is lower and so we needed to power up to 1W to check this alignment.

I have left the mirror we took out on the table on the -Y side labelled as 'HR mirror taken out of JACT-BS1'. Need to check which exact mirror this is with Masayuki on Monday.

Keita locked the cavity manually with the REFL PD and optimised the amount of light falling onto the TRANS PD.

I powered down to 100mW and de-energised the rotation stage and closed the light pipe at the end of the day. We also had the rotation stage de-energised and locked out when we were working in chamber.

ISC

Images attached to this report

H1 IOO - JAC work Friday Feb/20/2026 (Jennie, Rahul, Keita)

keita.kawabe@ligo.org — Fri, 20 Feb 2026 16:49:51 -0800

Author: keita.kawabe@ligo.org

Report ID: 89217

Modulation index measurement for 45M and 9M, they're healthy.

1W into JAC, no WFS for IMC, ITMY single bounce. Scanned OMC with both 45MHz minimal power (~4dBm) and 9MHz full (~27dBm), then both in full power, then only 45MHz in full (see screen shot).

Jennie will post the modulation index later, but the peaks look healthy to me.

The alignment into IMC was rather off in PIT and the guardian had a hard time locking IMC (I changed the lock threshold in the guardian). We didn't move MC, didn't bother to do any thorough investigation, but either JAC or MC mirrors moved. Maybe we have to lock IMC, use WFS for MC, and steer JM3 and see if the MC mirrors will be driven far from where they are. If they are we might have to touch up in-chamber alignment again.

JAC TRANS BS was swapped with the real one (laser window with AR only on one surface).

We replaced the JAC TRANS BS (which was a temporary high reflector until today) with the real one that is just a bare glass (the reflectivity is 7% or so depending on AOI).

We locked JAC with RF, was able to see the beam coming to the TRANS PD but wasn't able to see the reflection of PD, so we raised the power to 1W.

Initially the beam was missing the PD because the new optic is thinner than the temporary one. We realigned the optic to steer the beam back to PD. Since we could not directly see the PD surface, we just steered the beam up and down, left and right until the PD output starts to drop, and put the beam roughly in the middle.

We were able to see the PD reflection using an IR card and an IR viewer. There were two reflection blobs (which was the case before, too), and I moved the JAC TRANS BD in +X direction by 1/4~3/8" to catch both.

INS, IOO, ISC

Images attached to this report

LHO General - OPS Day Shift Summary

ibrahim.abouelfettouh@ligo.org — Fri, 20 Feb 2026 15:57:55 -0800

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 89216

TITLE: 02/20 Day Shift: 1530-0030 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

Calm day. HAM1 work continued.

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
22:49	SAF	LVEA is Laser SAFE	LVEA	NO*	LVEA is Laser SAFE Bifurcated HAM1/2	16:49
15:42	FAC	Randy	LVEA	N	Looking at test stand	16:15
15:42	FAC	Nellie	LVEA	Y	Technical Cleaning	18:35
16:48	VAC	Jordan	LVEA	N	Checking on HAM7	16:53
17:33	ISC	Keita	LVEA	Y	HAM1 Lightpipe	18:33
18:35	EPO	Maggie + 30	Overpass	N	Touring	19:24
19:40	EPO	Cassidy	Overpass +30	N	Touring	20:31
20:31	PEM	Robert	EX	N	Grounding measurement	21:44
21:07	OPS	Ryan S	Optics Lab	Y	SPI Work	23:17
21:23	ISC	Rahul, Keita	LVEA	Y	HAM1, rahul out at 23:15UTC	23:24
21:47	ISC	Jennie	LVEA	Y	HAM1	23:47
23:36	PEM	Robert	EX	N	Grounding measurement	01:36

H1 General - Quarterly trends of HWWD bits for indication of negative function

anthony.sanchez@ligo.org — Fri, 20 Feb 2026 14:56:12 -0800

Author: anthony.sanchez@ligo.org

Report ID: 89215

Famis 39976 Inspect quarterly trends of HWWD bits for indication of negative function.

All traces have had some motion on it in the last 91 days.

Images attached to this report

H1 SUS - SUS HRTS LO2 optic-prism glued

rahul.kumar@ligo.org — Fri, 20 Feb 2026 13:20:25 -0800

Author: rahul.kumar@ligo.org

Report ID: 89214

Yesterday afternoon I glued prisms to the LO2 optic for HRTS - see pictures attached.

This optic (D2100495-V5-LO2-M1-0002) will be shipped to LLO.

SUS

Images attached to this report

H1 SEI - SEI seismometer mass position check - Monthly

anthony.sanchez@ligo.org — Fri, 20 Feb 2026 11:51:11 -0800

Author: anthony.sanchez@ligo.org

Report ID: 89213

Famis 38888 SEI seismometer mass position check - Monthly :

Checking T240
Checking STS
Finished
Averaging Mass Centering channels for 10 [sec] ...
2026-02-20 11:36:02.279522

There are 12 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -1.716 [V]
ETMX T240 2 DOF Y/V = -1.819 [V]
ETMX T240 2 DOF Z/W = -0.998 [V]
ITMX T240 1 DOF X/U = -2.377 [V]
ITMX T240 1 DOF Z/W = 0.459 [V]
ITMX T240 3 DOF X/U = -2.547 [V]
ITMY T240 3 DOF X/U = -1.089 [V]
ITMY T240 3 DOF Z/W = -3.077 [V]
BS T240 2 DOF Z/W = 0.346 [V]
BS T240 3 DOF X/U = -0.518 [V]
HAM8 1 DOF Y/V = -0.428 [V]
HAM8 1 DOF Z/W = -0.728 [V]

All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.006 [V]
ETMX T240 1 DOF Y/V = -0.037 [V]
ETMX T240 1 DOF Z/W = -0.03 [V]
ETMX T240 3 DOF X/U = -0.024 [V]
ETMX T240 3 DOF Y/V = -0.07 [V]
ETMX T240 3 DOF Z/W = -0.043 [V]
ETMY T240 1 DOF X/U = 0.057 [V]
ETMY T240 1 DOF Y/V = 0.198 [V]
ETMY T240 1 DOF Z/W = 0.253 [V]
ETMY T240 2 DOF X/U = -0.087 [V]
ETMY T240 2 DOF Y/V = 0.215 [V]
ETMY T240 2 DOF Z/W = 0.046 [V]
ETMY T240 3 DOF X/U = 0.268 [V]
ETMY T240 3 DOF Y/V = 0.085 [V]
ETMY T240 3 DOF Z/W = 0.136 [V]
ITMX T240 1 DOF Y/V = 0.289 [V]
ITMX T240 2 DOF X/U = 0.131 [V]
ITMX T240 2 DOF Y/V = 0.257 [V]
ITMX T240 2 DOF Z/W = 0.242 [V]
ITMX T240 3 DOF Y/V = 0.119 [V]
ITMX T240 3 DOF Z/W = 0.061 [V]
ITMY T240 1 DOF X/U = 0.062 [V]
ITMY T240 1 DOF Y/V = 0.159 [V]
ITMY T240 1 DOF Z/W = 0.027 [V]
ITMY T240 2 DOF X/U = 0.021 [V]
ITMY T240 2 DOF Y/V = 0.243 [V]
ITMY T240 2 DOF Z/W = 0.16 [V]
ITMY T240 3 DOF Y/V = 0.082 [V]
BS T240 1 DOF X/U = 0.261 [V]
BS T240 1 DOF Y/V = -0.212 [V]
BS T240 1 DOF Z/W = -0.179 [V]
BS T240 2 DOF X/U = 0.142 [V]
BS T240 2 DOF Y/V = -0.271 [V]
BS T240 3 DOF Y/V = 0.061 [V]
BS T240 3 DOF Z/W = -0.263 [V]
HAM8 1 DOF X/U = -0.3 [V]

Assessment complete.
Averaging Mass Centering channels for 10 [sec] ...

2026-02-20 11:36:14.268587
There are 2 STS proof masses out of range ( > 2.0 [V] )!
STS EY DOF X/U = -4.582 [V]
STS EY DOF Z/W = 2.384 [V]

All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.51 [V]
STS A DOF Y/V = -0.798 [V]
STS A DOF Z/W = -0.581 [V]
STS B DOF X/U = 0.108 [V]
STS B DOF Y/V = 0.953 [V]
STS B DOF Z/W = -0.309 [V]
STS C DOF X/U = -0.871 [V]
STS C DOF Y/V = 0.868 [V]
STS C DOF Z/W = 0.593 [V]
STS EX DOF X/U = 0.507 [V]
STS EX DOF Y/V = -0.551 [V]
STS EX DOF Z/W = -0.392 [V]
STS EY DOF Y/V = 1.204 [V]
STS FC DOF X/U = 0.153 [V]
STS FC DOF Y/V = -1.174 [V]
STS FC DOF Z/W = 0.637 [V]

Assessment complete.
Results copied to clipboard

LHO VE - Fri CP1 Fill

david.barker@ligo.org — Fri, 20 Feb 2026 10:56:04 -0800

Author: david.barker@ligo.org

Report ID: 89212

Fri Feb 20 10:13:20 2026 INFO: Fill completed in 13min 17secs

Images attached to this report

H1 TCS - CHETAX

daniel.sigg@ligo.org — Fri, 20 Feb 2026 10:26:37 -0800

Author: daniel.sigg@ligo.org

Report ID: 89211

The slow controls software was updated to include the ChetaX electronics. The chassis is currently in the MSR for test purposes, but will be moved to the cheta lab next week.

Channels are located under H1:AWC-ITMX.

LHO General - OPS Day Shift Start

ibrahim.abouelfettouh@ligo.org — Fri, 20 Feb 2026 07:41:59 -0800

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 89210

TITLE: 02/20 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: MAINTENANCE
Wind: 14mph Gusts, 10mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.21 μm/s
QUICK SUMMARY:

IFO is IDLE for PLANNED MAINTENANCE

JAC/HAM1 work continues

H1 CDS - Comment to h1iscex TIM+ADC error

david.barker@ligo.org — Fri, 20 Feb 2026 07:41:42 -0800

Author: david.barker@ligo.org

Report ID: 89209

May have been due to in-rack work. Robert may have been working on ground investigations at the time, the EX lights were not turned off until 17:49 (+23 mins from glitch).

H1 CDS - Comment to h1ascimc restarted and DAQ restarted

david.barker@ligo.org — Fri, 20 Feb 2026 07:36:24 -0800

Author: david.barker@ligo.org

Report ID: 89208

There were some issues with the new code, so we reverted h1ascimc back to its original code at 13:40. We will try again next week.

When h1ascimc was restarted by itself, h1iopasc0 ran long and reported a DAC error, though on the 16bit-DAC MEDM there were no associated FIFO errors reported.

When h1ascimc was started as part of a complete model restart (rtcds start --all) this DAC error does not appear.

The DAC error is clearable by DIAG-RESET'ing the IOP, but we are unsure if the DAC is a cycle behind at this point. At the moment the safest restart if DAC errors appear is a full restart of all models.

H1 CDS - h1iscex TIM+ADC error

david.barker@ligo.org — Thu, 19 Feb 2026 20:06:01 -0800

Author: david.barker@ligo.org

Report ID: 89207

At 17:26 Thursday 19feb2026 h1iopiscex had a timing glitch causing a TIM+ADC error in its state word.

At 20:00 I restarted all the models which cleared the error.

Images attached to this report

H1 IOO - Comment to JAC work Thu. Feb/19/2016 morning (Mitch, Jennie, Jason, Betsy, Keita)

keita.kawabe@ligo.org — Thu, 19 Feb 2026 18:30:21 -0800

Author: keita.kawabe@ligo.org

Report ID: 89205

Afternoon work, REFL path aligned, RF lock works (Jennie, Jason, Betsy, Daniel, Keita)

It seemed as if what was supposed to be TFP after HWP was not really TFP, it was temporarily set aside.

REFL path to the JAC REFL RFPD was aligned without TFP. 100mW into JAC was enough to see the REFL beam there.

DC responded as expected.

There was a confusion about which demod chassis was used for JAC, which was sorted out by Daniel who subsequently set the demod phase. I zero-ed the dark offset.

I copied the JAC lock filter from dither path to JAC-L_SERVO path, locked JAC with dither, disabled the input to the dither servo and enabled RF locking in parallel, which worked just fine. I made rough changes to the RF servo to bump up the UGF to ~400Hz without too much gain peaking, I haven't tried anything aggressive to squash the residual motion below 200Hz, you might want to tweak it further.

I didn't disable the dither itself for the JAC PZT so we can compare the spectrum of RF and dither side by side. See attached, this was measured with 100mW into JAC, note that the dither error signal is scaled. References are with the purge air on and current traces are with the purge air completely turned down.

Guardian needs to be changed to allow smooth locking with RF.

Images attached to this report

H1 IOO - JAC work Thu. Feb/19/2016 morning (Mitch, Jennie, Jason, Betsy, Keita)

keita.kawabe@ligo.org — Thu, 19 Feb 2026 18:15:30 -0800

Author: keita.kawabe@ligo.org

Report ID: 89197

Beam dump for HAM1-HAM2 septum window AR reflection.

This was installed.

Beam dump for the -Y door viewport reflection.

Jason and Betsy installed it. There seems to be a discussion as to whether or not something else needs to be done.

EOM and JAC power budget again.

We measured the power at various places. While Jason held the power meter head still, I ran the statistics function of the power meter for a few seconds. I only list the mean and the standard deviation.

Wrong pol is king of large, ~0.2% of the main beam power coming out of EOM. That's 200mW when 100W goes through the EOM.

JAC throughput of 92% is not great, but Jason says the alignment and the matching are not really optimised.

JAC input	112mW+-462uW
EOM input = JAC output	103mW+-6.3mW	JAC OUT/IN = 0.92+-0.06
EOM front AR reflection	57uW+-4.4uW	EOM AR/IN = (5.5+0.5)*1e-4
EOM output (including the wrong pol beam)	96.9mW+-1.4mW
EOM wrong pol beam	226uW+-17uW	EOM wrong pol/IN = (2.2+-0.2)*1e-3
EOM main pol (= out total - wrong pol)	96.7mW +-1.4mW	EOM main pol/IN = .9978+-2e-4

INS, IOO, ISC

Images attached to this report

H1 CDS - Comment to Update to JAC & IMC ASC models

jennifer.wright@ligo.org — Thu, 19 Feb 2026 17:56:47 -0800

Author: jennifer.wright@ligo.org

Report ID: 89206

Jennie W, Dave B, EJ D, Erik V, Keita K, Daniel S, Jeff K, Olli P,

This morning I rebuilt the model again before it was restarted to add back in the IMC-PZT_PIT_OUT_DQ and H1:IMC-PZT_YAW_OUT_DQ channels in the top level of h1ascimc so as to avoid removing these channels from the GDS broadcast channel list.

Unfortunately this change did not get propagated to the live model today (it was not built with the rev-locked tag). This caused some confusion when the model + DAQ restart happened ( alog #89196). I had forgotten to SDF the PZT sliders for IMC-PZT_OUT and so this mis-aligned the beam to the JAC. Keita brought this back by altering the IMC sliders and we were able to continue with optics work in HAM1.

On the CDS side, none of my changes from today or yesterday have been uploaded to the 'rev-locked version of the model so everything was restarted with the old model config from yesterday morning. We will aim to restart with model changes to h1ascimc (that I made last night and this morning) at sometime Monday morning.

IOO, ISC

Images attached to this report

H1 SUS - PM1, RM1, RM2, JM1, JM3 COILOUT/DAMP filters updated to solve our confusion

oli.patane@ligo.org — Thu, 19 Feb 2026 16:42:32 -0800

Author: oli.patane@ligo.org

Report ID: 89198

Rahul, Jeff, Oli

In December 2025 when we needed to compensate for the HAM1 DACs moving from 16- to 28-bit, we had decided to have FM10 in the COILOUTF bank be gain(1024), and put the remaining gain(4) upstream in multiple other places (88553). This led to our confusion today when we realized that when taking transfer functions for PM1 and JM3, the TEST banks had gone back to gains of 1 a couple weeks ago, and since we had damping off, the extra gain wasn't going through to the excitation. This might at least partially be why PM1 had dropped in magnitude, and why the JMs are so low in magnitude too.

To solve confusion, I've gone through PM1, RM1, RM2, JM1, and JM3 and removed the extra gain(4) that's in:
- DAMP bank FM4
- TEST bank gains (if still there)
- OPTICALIGN gains
- LOCK filter bank gains
Then I updated the gains in COILOUTF FM10 from gain(1024) to gain(4096).

I've sdf'd the values and loaded in the changed filter modules. I also committed the filter file.

*To remove future confusion about the difference in value of the "28BitDAC" filter module in COILOUTF FM10, I am going to go through all the suspensions and change the name of that filter from "28BitDAC" to be something like "16to28Bit" or "18to28Bit" depending on the previously used DAC bits

CDS

H1 General - Ops DAY Shift Start

oli.patane@ligo.org — Thu, 19 Feb 2026 16:39:29 -0800

Author: oli.patane@ligo.org

Report ID: 89204

TITLE: 02/20 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: More HAM1 alignment work today
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
22:49	SAF	LVEA is Laser SAFE	LVEA	NO*	LVEA is Laser SAFE Bifurcated HAM1/2	16:49
15:00	FAC	Nellie	LVEA	YES	Tech clean	15:04
15:00	FAC	Kim	LVEA	YES	Tech clean	15:38
15:30	FAC	Randy	LVEA	n	Working on test stand	19:58
16:17	VAC	Jordan	LVEA	YES	Turning down HAM1 purge air, HAM7 continuing leak checks	16:24
16:30	EE	Fil	MER	n	Electronics work	18:32
16:36	FAC	Kim	LVEA	YES	Tech clean	17:23
17:13	JAC	Keita	LVEA	YES	JAC alignment	20:11
17:13	VAC	Gerardo	LVEA	YES	Turning up HAM1 purge air	17:17
17:20	EE	Marc	MER	n	Joining Fil for electronics rack work	18:32
17:22	JAC	Jason	LVEA	YES	JAC alignment	20:23
17:59	VAC	Jordan, Travis	LVEA	n	HAM7 leak checks	18:23
18:21	SPI	RyanS	OpticsLab	y(local)	SPI setup	21:42
18:24	JAC	Jennie	LVEA	YES	JAC alignment	20:11
18:39		Betsy	LVEA	YES	JAC work	20:23
18:50	JAC	Rahul	LVEA	YES	Checking on JAC team	19:02
18:51	SUS	Ibrahim	LVEA	n	Helping Randy at test stand	19:58
19:10	VAC	Gerardo, Jordan, Travis	LVEA	n	CP1 pump	20:11
19:14	SPI	Jeff	OpticsLab	y(local)	SPI work	21:42
20:07	PEM	Robert	EX	n	Grounding himself	21:23
20:49	FAC	Randy	LVEA	n	Test stand work	23:01
21:21	TCS	Sophie	JOAT Lab	n	Taking photos	21:39
21:55		Betsy	LVEA	YES	Opening light pipe	21:57
21:56	TCS	Sophie	JOAT Lab	n	Taking more pictures	22:03
22:03	FAC	Ibrahim	LVEA	n	Test stand work	23:01
22:43	JAC	Jason, Keita	LVEA	YES	JAC alignment	00:43
22:48	EE	Marc	LVEA	n	Cable intel	23:44
22:55	TCS	Sophie, Shreyan	JOAT Lab	n	Populating tables	ongoing
23:01	SPI	RyanS	OptLab	n	Setting up SPI	00:23
23:03	JAC	Jennie	LVEA	YES	JAC alignment	ongoing
23:11	FAC	Tyler, 2 contractors	LVEA	n	Checking out HVAC equipment	23:36
23:25	JAC	Betsy	LVEA	YES	JAC allignment	00:06
23:26	SPI	Jeff	OptLab	n	SPI work	00:18
23:35	EE	Tony, Fil	LVEA	N	Grabbing Ladder	23:57

H1 SUS - 2nd HRTS OM0 Optic-Prisms glued - for LHO

rahul.kumar@ligo.org — Thu, 19 Feb 2026 16:06:03 -0800

Author: rahul.kumar@ligo.org

Report ID: 89203

RyanC, Rahul

We glued prisms (primary - sapphire and secondary - metal) to the HRTS OM0 fused silica Optic, meant for LHO (D2100495-V5-OM0-02).

Attaching two pictures below for reference - they show the two prism glued to the barrel and the four magnet bases on the AR side of the optic.

I will post the details about its metrology later on.

---

OM0 optic meant for LLO has already been processed (i.e. prim glued) and shipped in Jan2026 - see alog 88786 for details.

SUS

Images attached to this report

H1 AOS - CHETA updates

sophie.muusse@ligo.org — Thu, 19 Feb 2026 14:13:23 -0800

Author: sophie.muusse@ligo.org

Report ID: 89200

S. Muusse, C. Compton, S. Goswami

We started populating and aligning optics on the second table. Most optics are now mounted and the beam is aligned upto M3 as per the fintrace model. We have aligned with the PD pick off in to save realignment later.

Construction begun on the camera can (D1300703) but did not get far as the screws which are fixed into the side panels (D2500165) are not long enough to reach the nuts attached to the other face of the box. Pictures of these components are attached.

We attached the viewport housing on the table which fits as expected. (photos attached)

Images attached to this report

Non-image files attached to this report

0920_gtrace_layout.pdf

H1 PSL - PSL Status Report Weekly FAMIS

oli.patane@ligo.org — Thu, 19 Feb 2026 14:11:11 -0800

Author: oli.patane@ligo.org

Report ID: 89202

Closes FAMIS#39752, last checked 89164

Laser Status:
NPRO output power is 1.841W
AMP1 output power is 70.47W
AMP2 output power is 138.8W
NPRO watchdog is GREEN
AMP1 watchdog is GREEN
AMP2 watchdog is GREEN
PDWD watchdog is GREEN

PMC:
It has been locked 0 days, 2 hr 51 minutes
Reflected power = 26.95W
Transmitted power = 104.0W
PowerSum = 131.0W

FSS:
It has been locked for 0 days 0 hr and 0 min
TPD[V] = 0.4856V

ISS:
The diffracted power is around 3.8%
Last saturation event was 0 days 2 hours and 9 minutes ago

Possible Issues:
PMC reflected power is high

LHO FMCS - HVAC Fan Vibrometers Check FAMIS

oli.patane@ligo.org — Thu, 19 Feb 2026 14:07:04 -0800

Author: oli.patane@ligo.org

Report ID: 89201

Closes FAMIS#39855, last checked 89138

Corner Station Fans (attachment1)
- All fans are looking normal and within range.

Outbuilding Fans (attachment2)
- All fans are looking normal and are within range.

PEM

Images attached to this report

LHO VE - Leak Checking of the HAM7 +Y door ports and the Relay Tube

jordan.vanosky@ligo.org — Thu, 19 Feb 2026 13:37:31 -0800

Author: jordan.vanosky@ligo.org

Report ID: 89199

Now that HAM7 is at sufficient pressure (6.4E-7 Torr as of this post) we helium leak checked the two re-installed 12" CF blanks removed for table locking and the entire relay tube assembly which had been removed for the viewport adapter on HAM5.

The Helium background was unstable, so we turned on the HAM7 cleanroom (on 2/18 afternoon) to help flush the area of helium overnight.

Today the background stabilized around 1.5E-10 Torr-l/s, so we were able to continue leak checking. No significant helium signal observed above the leak detector background which hovered between 1.5&2E-10 Torr-l/s during leak checking.

HAM7 continues to pump down with the turbopump, next steps are chamber RGA scans.

Images attached to this report

H1 CDS - h1ascimc restarted and DAQ restarted

erik.vonreis@ligo.org — Thu, 19 Feb 2026 12:13:46 -0800

Author: erik.vonreis@ligo.org

Report ID: 89196

DAQ was restarted around 12:02 PM PST after restarting h1ascimc.

H1 SUS - Comment to PM1 troubleshooting log

daniel.sigg@ligo.org — Thu, 19 Feb 2026 10:46:54 -0800

Author: daniel.sigg@ligo.org

Report ID: 89195

Is this a difference of the coils or sensors? One thing that changed was the LIGO DAC. Could there be a factor of 4 difference in gain due to a confusion between 18-bit, 20-bit, and LIGO DACs?

LHO VE - Thu CP1 Fill

david.barker@ligo.org — Thu, 19 Feb 2026 10:39:13 -0800

Author: david.barker@ligo.org

Report ID: 89194

Thu Feb 19 10:12:02 2026 INFO: Fill completed in 11min 58secs

Images attached to this report

H1 SUS - JM3 TFs after OSEM centering

oli.patane@ligo.org — Thu, 19 Feb 2026 09:33:01 -0800

Author: oli.patane@ligo.org

Report ID: 89193

Yesterday afternoon Rahul centered the OSEM flags on JM3 (89187). This morning I took another set of transfer functions to check that they're looking good. Flags are well centered (pic), and transfer functions are looking good (TFs).

Settings:
- ISI Locked
- OFFSETs OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-19_1645_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12913
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/Results/2026-02-19_1645_H1SUSJM3_M1_ALL_TFs.pdf
r12914

Images attached to this report

Non-image files attached to this report

2026-02-19_1645_H1SUSJM3_M1_ALL_TFs.pdf

H1 SUS - PM1 troubleshooting log

oli.patane@ligo.org — Thu, 19 Feb 2026 08:37:03 -0800

Author: oli.patane@ligo.org

Report ID: 89184

Rahul, Fil, Oli

We still don't know why PM1 looks different now than it did when we installed it back in May 2025. Currently, we've nailed it down to two possibillities: (1) there's an issue with PM1 somewhere between the satamp and the in-chamber stuff, or (2) the December 2025 satamp swap to a modified satamp changed the magnitude of PM1 (we are not sure if this makes sense).

Here are some measurements we took yesterday and the things we've looked at so far.

Satamp

We were worried about the satamp, which is a dual satamp, swapped in in December 2025 (88590), with JM3 taking up the other half, so I took some transfer functions yesterday morning for both PM1 and JM3. I compared JM3 now to how it looked when we first installed it in December 2025, and it looks exactly the same, no drop in magnitude for JM (JM3 Dec2025 vs Feb 2026), and no increase in magnitude for PM1 (PM1 May 2025 vs Feb 2026).

Fil then swapped all the PM1 cables on the satamp with all the JM3 cables on the satamp. This made it so the only difference between the previous and these measurements is the part of the satamp used. These measurements for PM1 and JM3 still looked the same as the earlier measurement, so it's not the satamp (PM1 JM3 comparison). These comparison plots really show how much PM1 changed compared to JM3.

All other in-air electronics

The only other difference from the measurements last May for PM1 should be the coil driver, since the other one failed (88998). The new coil driver is modified, just like the old one, and is being correctly compensated for in the coil drive filter banks. To check this, as well as the rest of the in-air electronics, Fil swapped everything back to nominal EXCEPT for the cables that run from the sat amp out to the chamber. This way, JM3 is using the in-air electronics from PM1, and PM1 is using the in-air electronics from JM3. I did a few transfer functions looking for any difference but both suspensions and electronics chains still look the same(PM1 L, PM1 P, JM3 P). This could mean that the issue with PM1 is due to something in the satamp-to-chamber cable or in vacuum.

OSEMs

We checked the spectra for the PM1 BOSEMs but we did it while the purge air was up, so they're very noisy and not very useful.

Satamp question

The only other thing we can think of that could've changed the magnitude of PM1 but not affect what we're seeing in JM3 would be due to the satamp swap in December. The new modified satamp was hooked up to PM1 and JM3 on December 18, 2025 (88588). JM3 was first tested the next day, and obviously we never got a measurement of JM3 with an unmodified satamp, so if it's possible for the satamp to change the magnitude of PM1, that might be what is happening. I haven't had time yet to check whether other suspensions show anything like that.

Measurement info
PM1
2026-02-18 1600
- ISI Locked
- alignment offsets OFF
- DAMP OFF for measured DOF, ON for other DOFs
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-18_1600_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12905
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-18_1600_H1SUSPM1_M1_ALL_TFs.pdf
12909

2026-02-18 1715
- satamp inputs swapped with JM3 (tfs look the same)
- ISI Locked
- alignment offsets OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data/2026-02-18_1715_H1SUSPM1_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12906
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Results/2026-02-18_1715_H1SUSPM1_M1_ALL_TFs.pdf
12909

JM3
2026-02-18 1600
- ISI Locked
- DAMP OFF
- alignment offsets OFF
- DAMP OFF for measured DOF, ON for other DOFs
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-18_1600_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
r12904
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Results/2026-02-18_1600_H1SUSJM3_M1_ALL_TFs.pdf
r12908

2026-02-18 1730
- satamp inputs swapped with PM1 (tfs look the same)
- ISI Locked
- alignment offsets OFF
- DAMP OFF
Data:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Data/2026-02-18_1730_H1SUSJM3_M1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
12907
Results:
/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/JM3/SAGM1/Results/2026-02-18_1730_H1SUSJM3_M1_ALL_TFs.pdf
r12908

Comparisons
PM1 May 2025 vs PM1 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_PM1_May2025vsFeb182026_ALL_TFs.pdf
r12911

JM3 Dec 2025 vs JM3 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_JM3_Dec2025vsFeb182026_ALL_TFs.pdf
r12912

JM3 Dec 2025 vs JM3 Feb 18 2026 vs PM1 May 2025 vs PM1 Feb 18 2026
/ligo/svncommon/SusSVN/sus/trunk/HTTS/Common/Data/allhttss_2026-02-18_PM1_JM3_PM1looksdifferent_ALL_TFs.pdf
r12910

Images attached to this report

Non-image files attached to this report

allhttss_2026-02-18_JM3_Dec2025vsFeb182026_ALL_TFs.pdf

allhttss_2026-02-18_PM1_May2025vsFeb182026_ALL_TFs.pdf

allhttss_2026-02-18_PM1_JM3_PM1looksdifferent_ALL_TFs.pdf

2026-02-18_1600_H1SUSPM1_M1_ALL_TFs.pdf

2026-02-18_1715_H1SUSPM1_M1_ALL_TFs.pdf

2026-02-18_1600_H1SUSJM3_M1_ALL_TFs.pdf

2026-02-18_1730_H1SUSJM3_M1_ALL_TFs.pdf

H1 General - Ops DAY Shift Start

oli.patane@ligo.org — Thu, 19 Feb 2026 07:33:19 -0800

Author: oli.patane@ligo.org

Report ID: 89192

TITLE: 02/19 Day Shift: 1530-0030 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, 10mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.36 μm/s
QUICK SUMMARY:

More HAM1 work today

H1 IOO - Comment to All known ghost beams in HAM1 identified, dumped except for septum window reflection (Jason, Betsy, Keita)

betsy.weaver@ligo.org — Wed, 18 Feb 2026 21:14:38 -0800

Author: betsy.weaver@ligo.org

Report ID: 89191

Picture of the beam coming back to the output periscope (8) is attached.

Images attached to this report

H1 CDS - Added JAC in-air shutter to medm screens

jennifer.wright@ligo.org — Wed, 18 Feb 2026 18:32:00 -0800

Author: jennifer.wright@ligo.org

Report ID: 89189

I added this shutter (shutter H1:SYS-MOTION_C_SHUTTER_M) to the main shutters screen at sitemap->LSC->Shutters. I also added a menu button that takes you to the control screen to the sitemap->IOO->JAC Overview screen, see pic.

IOO, ISC

Images attached to this report

H1 IOO - All known ghost beams in HAM1 identified, dumped except for septum window reflection (Jason, Betsy, Keita)

keita.kawabe@ligo.org — Wed, 18 Feb 2026 18:27:40 -0800

Author: keita.kawabe@ligo.org

Report ID: 89190

We locked JAC with 1W input to find ghost beams. Details will come after we're done with the septum window reflection, but anyway here is the list:

EOM AR reflection. Properly dumped today.
L1 reflections (front and back surface) are reflected by JAC output coupler and go through L1. Properly dumped today.
L2 reflections (front and back). Properly dumped today.
L3 reflections (front and back). Properly dumped today.
EOM wrong pol forward going beam. Changed the beam dump position today. This was brighter than I thought, we will measure the power again.
JM2 transmission. Already dumped, confirmed it's still there.
JM3 transmission. Already dumped, confirmed it's still there.
Septum window reflection. This was coming back horizontally in -Y direction, was about half inch off from the main beam at the top periscope mirror, and hitting the metal part at the top edge of the bottom peri mirror. Not dumped yet.
- We'll have to improvise something so the beam is dumped at the top periscope position before entering into the periscope structure. Something like a variation of the beam dump behind the top mirror of the JAC input periscope.

None of the new beam dumps are interfering with the main beam and JAC refl/trans.

INS, IOO, ISC

H1 CDS - Update to JAC & IMC ASC models

jennifer.wright@ligo.org — Wed, 18 Feb 2026 18:24:46 -0800

Author: jennifer.wright@ligo.org

Report ID: 89188

Jennie W, Ryan S

Summary: Ryan and I updated the JAC and IMC ASC models. We installed JM3 yesterday and so now the IMC cannot use the PSL PZT mirror as an alignment actuator. I have committed the changes to the svn but erik and dave will do some checks tomorrow before they commit to the revision locked version of the model and restart the DAQ. So changes are not 'live' yet.

The edits were made to h1ascimc.mdl which has top level blocks for IMC and JAC.

The JAC top level model sends signals directly to the PSL PZT mirror and these degrees of freedom are swapped as the PSL PZT basis P and Y are switched before input to the JAC due to the HAM1 input periscope.

I took out the feedback paths for PZT_P and PZT_Y that come out of the IMC block. The picture shows the old config and I have highlighted what I removed.

At the top level, IMC no longer sends signals to the PZT but instead to JM3. On the top level diagram, the signal JM3_P is sent via PCI cards to the channel "H1ASC-JM3_YAW_SUSHTTS" as pitch in the JAC basis is yaw in the IMC basis due to the HAM1 output periscope. The picture shows the old config and I have highlighted what I swapped.

The signal JM3_Y is sent via PCI cards to the channel "H1ASC-JM3_PIT_SUSHTTS" as yaw in the JAC basis is pitch in the IMC basis due to the HAM1 output periscope.

Within the IMC top names block I removed the output channels for the PZT from the WFS feedback path, we already had paths to feedback to JM3 within this path. The picture shows the new config.

I removed the PZT locking path from the LCKIN block and replaced it with one for JM3. The picture shows the new config. I am not sure we ever use this path (which is for dither asc control of the IMC) in the first place so maybe this was unneccessary.

I also removed the channels H1:IMC-PZT_YAW_OUT and H1:IMC-PZT_PIT_OUT from the DAQ channel list for the IMC model.

IOO, ISC

Images attached to this report

H1 SUS - HAM1 - JM3 (SUS Tip Tilt) BOSEM flags re-centered

rahul.kumar@ligo.org — Wed, 18 Feb 2026 17:00:13 -0800

Author: rahul.kumar@ligo.org

Report ID: 89187

SUS JM3 (Tip Tilt) update - This afternoon I went into the HAM1 chamber (when no one was working with the beam) and re-touched the BOSEM flags to center it with the LED/PD for half light. I will re-take TF measurements later on.

SUS

H1 General - Ops DAY Shift End

oli.patane@ligo.org — Wed, 18 Feb 2026 16:56:02 -0800

Author: oli.patane@ligo.org

Report ID: 89186

TITLE: 02/19 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: HAM1 work continued today
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:42	FAC	Crane tech	LVEA	YES	Crane work	17:58
15:45	VAC	Gerardo	LVEA	YES	Turning down purge air	16:00
15:45	FAC	Kim, Nellie	LVEA	YES	Tech clean (Nellie out 16:24)	16:28
16:55	SUS	Fil	LVEA	YES	Swapping cables for PM1 troubleshooting	17:02
16:59		Camilla	LVEA	n	Looking for parts	17:08
17:00	FAC	Kim	LVEA	n	Tech clean	17:32
17:08	FAC	Nellie	MY	n	Tech clean	16:08
17:11	FAC	Randy	LVEA	n	Measuring test stand	17:54
17:33	FAC	Kim	MX	n	Tech clean	18:23
17:49	SUS	Fil	LVEA	YES	Swapping more cables for PM1 troubleshooting	17:57
18:12	EE	Marc	MER	n		20:02
19:00	SUS	Fil	LVEA	YES	Swapping back cables	19:10
19:04	JAC	Jennie, Jason	LVEA	YES	HAM1 alignment	20:53
19:04	VAC	Gerardo	LVEA	N	Turning up HAM1 purge air	19:18
19:05	TCS	Camilla, Sophie, Shreyan	Prep Lab	Local	CHETA table work	20:18
19:09	JAC	Keita	LVEA	YES	Joining JAC crew	20:53
19:16	SUS	Rahul	LVEA	YES	Helping with JM3	20:54
19:16	JAC	Betsy	LVEA	YES	Wiring up JAC table	20:25
19:18	VAC	Jordan	LVEA	n	Checking on HAM7 vacs	20:03
20:20	PEM	Robert	EX	n	Grounding himself	21:44
20:29		RyanC	CER	n	Putting away dust monitor	20:32
20:35	EE	Marc, Fil	MY	n	Picking up cables	22:05
21:31	TCS	Camilla, Sophie, Shreyan	Prep lab	LOCAL	CHETA table work	22:56
21:34	FAC	Richard	LVEA	N/Y	Safety checks	21:46
21:41	VAC	Travis, Jordan	LVEA	n	Setting up leak checker on HAM7	23:11
22:28		Betsy	LVEA	YES	Checking out JAC table	23:05
22:36	VAC	Gerardo	LVEA	YES	Turning down purge air	22:16
22:50	PEM	Robert	EX	n	Geting more grounded	00:55
23:02		Betsy	LVEA	YES	Turning purge air back up	23:30
23:29	SUS	Rahul	LVEA	YES	Adjusting JM3 osem flags	23:55
23:37	JAC	Jason, Keita	LVEA	YES	JAC alignment	ongoing
23:40	JAC	Betsy	LVEA	yes	JAC table work	ongoing
00:04	VAC	Travis, Jordan	LVEA	n	HAM7 leak checking	00:31
00:16	TCS	Camilla, Sophie	OpticsLab	n	CHETA work	ongoing
00:17	TCS	Camilla, Sophie	LVEA	YES	Checking in with Betsy	00:31

H1 IOO - JAC to IMC MM still looks good, mismatching upper limit 0.24% (Jennie, Rahul, Jason, Betsy, Keita)

keita.kawabe@ligo.org — Wed, 18 Feb 2026 15:25:10 -0800

Author: keita.kawabe@ligo.org

Report ID: 89185

We refined the alignment from JAC to IMC by iterating small amount between JM2 and JM3. It was hard due to purge air and the suspended JM3, instead of relying on the IMC scan and minimize 1st order modes, we locked IMC and minimized the IMC REFL DC on average. After that the beam was still centered on JM3 well.

We closed the chamber and turned down the purge all the way and the alignment was indeed good. There was almost no 01 (PIT) mode power, 10 (YAW) mode power was less than 1% of 00 mode power, and the 20/02 mode power was 0.23 to 0.24%. See MM.png.

(To identify which mode is what, I intentionally misaligned JM3 in YAW (that causes PIT misalignment for IMC. See mode_identification.png.)

INS, IOO, ISC

Images attached to this report

H1 AOS - Setting Lens Position for SPI In-vac SuK Fiber Collimators: New Measurement Technique Yields Great Success; Both MEAS and REF Collimators Beam Waist Radius within +/- 0.1 [mm]

jeffrey.kissel@ligo.org — Wed, 18 Feb 2026 14:20:05 -0800

Author: jeffrey.kissel@ligo.org

Report ID: 89181

J. Kissel Executive Summary Using - the AxcelPhotonics butterfly diode laser, - the "beam splitter / near-field / bypass" measurement setup described in LHO:89123 to rapidly check the beam diameter at z = 0.991 [m] (near field) and z = 5.41 [m] (far field), - elevating the beam height elevated to 5 [inches] to avoid any sort of clipping on other optomechanical setups on the table from other teams, and - loosening the lens position set screws only just barely, - paired fiber collimators, in-vac feedthrus (with integrated patch cords), and ex-vac 7.5 m patch cables in-vac feedthrus Beam Path Char Date Collimator Feedthru (Pwr Transmission*) MEAS 2026-02-13 S0272503 S3228003 (100%) REF 2026-02-17 S0272502 S3228002 (99%) * Power transmission as reported from SWG:12296 I was "rapidly" tune the lens position, z_lens, for *both* the MEAS S0272503 and REF S0272502 fiber collimators to within 0.010998 (i.e. 11 [mm] - 2 [um]) with uncertainty of +/- 1 [um] , such that each fiber collimator sends out a free-space beam whose parameters meets SPI's requirements: - the desired waist radius (in both x/y dimensions) , w0 = 1.05 [mm], of within +/- 0.10 [mm], and - the desired waist position (in z), z0 = 0.0 [m] to within +/- 0.18 [m]. (where "rapidly" is in quotes: about 4 hours each from "install into measurement setup" and "I'm happy with a final full-position-vector scan). with no signs of strong astigmatism that I saw in the initial setup. (The later point confirms my suspicion that I was clipping on the EOM characterization setup, and there is *no* issue with the laser seed mode, polarization, or the beam splitters). Support Media The raw data from the beam profiles of each free-space beam are posted as 2026-02-17_spi_fc_S0272502_ft_S3228002_7p5mPatchCord_AxcelPhotonicsLaser.txt 2026-02-13_spi_fc_S0272503_ft_S3228003_7p5mPatchCord_AxcelPhotonicsLaser.txt where the columns are jammt-friendly format of z Position [cm], Y waist radius [um], X waist radius [um]. Notes: (1) as opposed to all previous data sets (e.g. LHO:89047, LHO:86350, LHO:84825) -- I added an additional measurement at z = 0.25 [m] to try to improve the accuracy of the fit beam. (2) X is "Axis 1" of the NanoScan parallel to the optical table, Y is "Axis 2," perpendicular to the table. As discussed in LHO:89099, jammt seems to import any three-column dataset such that the first column ends up fit as the "tangential w0," and the second column end up fit as the "w0." With a la mode, the data is typed in a matlab script manually, so X and Y data are modeled separately the entire time without rename, and thus kept consistent. Thus the intentional flip the X and Y axes in the text file such that a la mode and jammt are now both treating w0 = X = Axis 1 = parallel to table, and tangential w0 = Y = Axis 2 = perpendicular to the table. I imported these beam profiles into both matlab (to run a la mode) and jammt to obtain waist radius, w0, and waist position, z0, fits to the AxcelPhotonics beam profiles, see attached plots: S0272502 a la mode jammt S0272503 a la mode jammt Some pictures of the measurement setup with the NanoScan head at the new z = 0.25 [m] position (upstream of the beam splitter bypass): 2026-02-13_FC_S0272503_S3228003_MeasSetup.jpg 2026-02-17_FC_S0272502_S3228002_MeasSetup.jpg Some pictures of the clean fiber collimator + vacuum feedthru systems packed up after measurement: 2026-02-13_FC_S0272503_S3228003_PackedUp.jpg 2026-02-17_FC_S0272502_S3228002_PackedUp.jpg Detailed Analysis Results Here's a table of the fit results from both a la mode and jammt.

FC + FT S/N	Model	w0x [m]	z0x [m]	w0y [m]	z0y [m]
S0272502 + S3228002	a la mode	1.0392	-0.065196	1.0427	-0.020038
	jammt	1.0392	-0.06521	1.0427	-0.02007
S0272503 + S3228003	a la mode	1.0396	+0.17704	1.0282	-0.030537
	jammt	1.0396	+0.17702	1.0282	-0.03051

It's not a typo, the two fitting softwares agree to within the precision of the each display; +/- 10 [um] on both the waist radius and waist position. From here on in this section, since I intentionally paired up fiber collimators and fiber feedthrus to match the last two digits of serial number, I'll refer to them as either "MEAS = S[...]03", or "REF = S[...]02". From the table of fits, you see that the statement in the executive summary about the waist position, z0 = 0.0 +/- 0.18 [m], is defined expanded to cover the X axis waist position of MEAS = S[...]03 z0x = +0.177 [m]. But really, the other axis of the MEAS = S[...]03 FC+FT pair is at z0y = -0.031 [m], and the REF = S[...]02 FC+FT pair is within z0x = -0.065 [m], and the best z0y = -0.020 [m]. So the waist positions are really *quite* close to 0.0 [m]. Good. So let's use these numbers to do recast the fit (using jammt numbers only) into context: (1) Percent Difference between desired waist radius and final measured waist radius: REF, S[...]02 :: (w0x, w0y) = ([1.0392 1.0427] - 1.05) / 1.05 = [-0.0102860 -0.0069524] = [-1.0% -0.7%] Within 1.050 +/- 0.1 [mm] = 1.050 [mm] +/- 9.5 [%] = [1.15 0.95] [mm]? Both axes waist radius are a factor of 10x better than reqs. MEAS, S[...]03 :: (w0x, w0y) = ([1.0396 1.0282] - 1.05) / 1.05 = [-0.0099048 -0.020762] = [-1.0% -2.1%] Within 1.050 +/- 0.1 [mm] = 1.050 [mm] +/- 9.5 [%] = [1.15 0.95] [mm]? Both axes waist radius are a factor of 5x better than reqs. (2) Rayleigh Range: (zR := pi * w0^2 / lambda) REF, S[...]02 :: (zRx,zRy) = (3.1886, 3.2102) [m] MEAS, S[...]03 :: (zRx,zRy) = (3.1911, 3.1215) [m] There's no requirement on where the Rayleigh range sits, but for a waist radius of w0 = 1.05 [mm], we would expect a Rayleigh Range of zR = 3.255 [m], and these values are at most z = -13 [cm] from that or 4% "short" of the target value. This doesn't really matter to SPI, as long as the Rayleigh Range is somewhere in between the ISIK breadboard and the ISIJ reflector 15.427 [m] away. The real requirement is the spot size at the ISIJ reflector, which we need to keep at the design value of 5 [mm] (whose value was determined with the original design waist radius of 1.05 [mm], and the acceptance that we didn't have enough room on the ISIK transceiver breadboard to install telescopic lens solutions to keep the spot size around 1 [mm] both within the transceiver *and* at the ISI reflector). (3) Astigmatism: A := (zRx - zRy) / (zRx + zRy) REF, S[...]02 = -0.003376 = -0.3% MEAS, S[...]03 = +0.011026 = +1.1% Here, again, there's been no requirement on the astigmatism, but ~1% astigmatism doesn't smell too terrible. (4) Spot size at 15.427 [m]: w(z) = w0 * sqrt(1 + (z/zR)^2) REF, S[...]02 :: (x,y) = (5124.569, 5155.038) [um] MEAS, S[...]03 :: (x,y) = (5194.496, 5075.909) [um] Recall the design value of waist radius at the ISIJ reflector, z = 15.427 [m], is w(z = 15.427) = 5 [mm]. As discussed in SWG:12273, that ADC noise with the large spot size is limiting the sensitivity of the pitch and yaw readout, as dx/dTheta ~ sqrt(8/pi) L / w(z). But still, a 1.1% level of astigmatism -- which would result in a different sensitivity / noise performance between pitch and yaw, means that pitch is only ~2.1% worse than yaw. Great! We're good to go!

Images attached to this report

Non-image files attached to this report

2026-02-17_spi_fc_S0272502_ft_S3228002_7p5mPatchCord_beamprofile_fit_AxcelPhotonics_NearField.pdf

2026-02-13_spi_fc_S0272503_ft_S3228003_7p5mPatchCord_beamprofile_fit_AxcelPhotonics_NearField.pdf

2026-02-17_spi_fc_S0272502_ft_S3228002_7p5mPatchCord_AxcelPhotonicsLaser.txt

2026-02-13_spi_fc_S0272503_ft_S3228003_7p5mPatchCord_AxcelPhotonicsLaser.txt

H1 IOO - IMC ASC model needs a better JAC integration

keita.kawabe@ligo.org — Wed, 18 Feb 2026 14:15:50 -0800

Author: keita.kawabe@ligo.org

Report ID: 89183

Or, rather, a better JM3 integration and PSL unintegration.

I made a temporary IMC_WFS_MASTER and IMC_WFS_OUTMATRIX_kk screen such that it's easy to route IMC WFS signal to JM3, not the PSL PZT, because I wanted something that works now.

However, right after I made what looks to be an OK screen, I realized that this doesn't work. PIT signal should be routed to JM3 YAW and vice versa. No fully-working IMC WFS until the next model update.

In addition, earlier today Daniel suggested to nuke PSL PZT from the IMC ASC (good idea).

If you want to revert back to the old medm, copy the backup

/opt/rtcds/userapps/trunk/asc/common/medm/imc/IMC_WFS_MASTER_BAK_20260218.adl

/opt/rtcds/userapps/trunk/asc/common/medm/imc/IMC_WFS_MASTER.adl

CDS, IOO, ISC

Images attached to this report

LHO VE - Wed CP1 Fill

david.barker@ligo.org — Wed, 18 Feb 2026 11:29:44 -0800

Author: david.barker@ligo.org

Report ID: 89182

Wed Feb 18 10:12:42 2026 INFO: Fill completed in 12min 38secs

Gerardo confirmed a good fill curbside.

Images attached to this report

H1 IOO - Comment to JAC EOM moved, looks OK (Jason, Betsy, Keita)

masayuki.nakano@ligo.org — Wed, 18 Feb 2026 09:21:22 -0800

Author: masayuki.nakano@ligo.org

Report ID: 89180

Let me point out that the term “mode matching” used in Jennie’s post is not exactly accurate in this case; it would be more precise to refer to it as the TEM20/02 mode peak fraction. Since there is a large misalignment, the second-order modes are also enhanced. Therefore, that contribution should be subtracted before attributing the remaining fraction to mode mismatch.

H1 General - Ops DAY Shift Start

oli.patane@ligo.org — Wed, 18 Feb 2026 07:32:38 -0800

Author: oli.patane@ligo.org

Report ID: 89179

TITLE: 02/18 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
SEI_ENV state: MAINTENANCE
Wind: 3mph Gusts, 1mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.44 μm/s
QUICK SUMMARY:

More HAM1 work today