aLIGO LHO Logbook

H1 IOO - Comment to RTP test, ghosts from the new batch spare crystal, no ghost from the old batch spare (Elenna, Betsy, Keita)

betsy.weaver@ligo.org — Wed, 11 Feb 2026 18:36:30 -0800

Author: betsy.weaver@ligo.org

Report ID: 89125

Attached is the picture of the chip on the spare "older" crystal S/N10252003 The other picture shows the box labels of the EOM crystals and stat at LHO, namely: 10252003 chipped 10252007 to be swapped into the JAC EOM 2 newer ones which are having some scatter issues as Keita has written about

Images attached to this report

H1 General - OPS Wednesday Day shift summary

ryan.crouch@ligo.org — Wed, 11 Feb 2026 16:31:30 -0800

Author: ryan.crouch@ligo.org

Report ID: 89118

TITLE: 02/12 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 continues, HAM7 is pumping down.
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
16:10	FAC	Kim	LVEA	N*	Tech clean	17:30
17:10	SQZ	Keita	Optics lab	LOCAL	EOM	19:15
17:17	EE	Marc, Fil	LVEA, CER	N*	Pulling cables	00:46
17:28	FAC	Mitch	LVEA	N	Checks, WEST BAY	17:46
17:30	FAC	Kim	EndX	N	Tech clean	18:48
17:40	ISC	Betsy	LVEA	N*	Parts	17:48
17:49	SQZ	Betsy	Optics lab	LOCAL	Join Keita	19:15
17:54	ISC	Camilla	LVEA	N*	Bring out dog clamps	18:49
17:59	SQZ	Elenna	Optics lab	LOCAL	Join Keita	19:15
18:06	FAC	Randy	LVEA	N /Y	BSC2 tent, at height hazard	18:24
19:01	ISC	Jason, Oli, Jennie	LVEA	Y	HAM1, refl path, Viewport simulator	20:00
19:21	FAC	Eric	EndX	N	Chiller yard checks	19:35
21:20	SQZ	Keita	Optics lab	LOCAL	EOM?	23:32
21:33	ISC	Jason, Jennie, Tony	LVEA	Y	HAM1 work, refl alignment	ongoing
21:59	VAC	Gerardo, Jordan	LVEA	N*	HAM4 annulus ion work, height laser hazard	23:16
22:14	FAC	Mitch	LVEA	N	West bay checks	23:09
22:26	FAC	Richard	LVEA	N*	Safety checks	22:50
22:35	SQZ	Betsy	Optics lab	LOCAL	Join Keita	23:36
00:29	ISC	Betsy	LVEA	Y	HAM1	Ongoing

18:15 UTC HAM7 SEI SW watchdog trip from a H7 crash, FE & ADC errors on IOPSUSH7 SUSFC1, SUSSQZIN SUSAUXH7, IPC and DK error on SEIH7.

Dave restarted everything ~20 minutes later

H1 IOO - RTP test, ghosts from the new batch spare crystal, no ghost from the old batch spare (Elenna, Betsy, Keita)

keita.kawabe@ligo.org — Wed, 11 Feb 2026 16:26:12 -0800

Author: keita.kawabe@ligo.org

Report ID: 89122

Following alog 89115, we found that the old batch crystal from that alog (S/N10252003) had a big chip at one corner. It is pretty bad we don't want to use that.

Betsy found another old batch (S/N10252007, "inspected 12/21/11" and UF tag dated 4/21/09), so we A-B-ed that one with the spare new batch (S/N B1913108).

The beam path was made as level as possible at 3" height using a beam leveling tool (a black metal thing with a tiny aperture at each inch of height).

We put the crystal on a platform that is roughly 2" 29/32 (which is about 2.4mm lower than 3"). The crystal is 4x4x40mm so that's about the right height.

We spent some time to make YAW alignment as good as we can for each of the crystals.

We scanned the beam in PIT from top to bottom (or bottom to top), each extreme is where the beam is almost clipped (but not actually clipped) by the top or the bottom face of the crystal.

Look at the attached, the new batch (left column) clearly shows multiple beams even though the focus is not as sharp as the old batch photos. As we misalign in PIT, the dark place moves relative to the main beam and the contrast changes too, but multiple ghost never went away. At the extrema (very close to the top or bottom edge) it looked as if the beam is better but I'm not sure it actually was.

The old batch (right) didn't show such a behavior. The beam shows something like a diffraction pattern but no separate ghost beams. Everything moved with the main beam. Not sure if the diffraction pattern came from the aluminum surface or EOM, but clearly this is MUCH better than the new batch.

Note, due to the apparatus (the steering mirror is 20" upstream of the EOM), we haven't searched in a huge PIT angle space, it's actually roughly +-4mrad or so, the angle is not negligible but it's more parallel displacement scan than an angle scan.

Also note, when the crystal was put in place it seems that there's some vertical deflection which was different for the old and the new. On the top two pictures, there's no change in the input alignment into the crystal.

Based on this observation, I'd say using the old batch makes sense. LHO people (Jennie, Rahul, Betsy and myself) had a brief conversation with Masayuki and MichaelL and we all agreed that that's the way to go.

INS, IOO, ISC

Images attached to this report

H1 IOO - Comment to RTP test beam path in the OSB optics lab (Elenna, Betsy, Jenne, Keita)

elenna.capote@ligo.org — Wed, 11 Feb 2026 16:24:24 -0800

Author: elenna.capote@ligo.org

Report ID: 89124

I made a mistake when providing calculations to Keita about the beam profile- I incorrectly input our distances as mm instead of cm. However, I think it's ok overall.

Keita and I put an available lens (f = 286.5 mm) into the beam path, and then used a thorlabs profiler on a rail to profile the resulting beam at five points. We measured distances from the lens to the profiler and accounted for the set back of our profiler from the edge of the mount, etc. This measurement allowed us to measure that the beam waist is roughly around the location of the laser, and is about 130 um in the x direction and 202 um in the y direction. Unfortunately, the beam quality isn't great, this is the best we could do. (Note, because of my mistake we chose not to use this particular lens, but it probably would have been fine for our measurements after all).

After some iteration, we determined that a f=401 mm lens was suitable, and we ended up placing it pretty close to the original lens location. We ran another profile measurement and found that we could achieve a beamsize of about 313 um in the y direction and 251 um in the x direction (different than Keita's reported numbers above because I originally fit an incorrect seed waist).

I have attached two plots. The first shows the profile of the beam with the original lens, and the second with the resulting lens that we have now used to measure the EOM crystal.

So, the beam is maybe a bit smaller than the beamsize on HAM1 that goes into the EOM crystal (around 350 um).

Images attached to this report

H1 SEI - SPI Fiber Collimator: Refined Collimation / Lens Position / Beam Waist Diameter Measurement Setup

jeffrey.kissel@ligo.org — Wed, 11 Feb 2026 14:31:26 -0800

Author: jeffrey.kissel@ligo.org

Report ID: 89123

J. Kissel After conferring with Sina about the results from LHO:89047 and armed with the plan described at the tail end of LHO:89099, went into the optics lab to improve the rapid iteration of beam waist diameter measurement by concocting an optical layout that can measure the beam at two z positions at the same time. See attached diagram and physical setup. Note -- the optical table has become over populated with in-vac EOM crystal characterization (and additional beam-scanning set up), so Keita and I shared space by having his setup be at 3 inch beam height and me at 4.5 inch setup. This just barely cleared his beam scan, so I intend to further increase my beam height to 5 inches. I only have preliminary results (without having changed the collimator lens position at all yet), but they showed hints of astigmatism, so I suspect: - the polarization of the emitted beam from the fiber collimator - the beam splitters - clipping on the beam scan from Keita's setup. Will confer with the team.SEI

Images attached to this report

Non-image files attached to this report

FiberCollimator_LensPosition_vs_OneBeamScan_TwoLocations.pdf

LHO General - Mid Station chilled water trending

eric.otterman@ligo.org — Wed, 11 Feb 2026 10:44:46 -0800

Author: eric.otterman@ligo.org

Report ID: 89121

I ran the chilled water pumps at the Mid stations this morning to exercise the bearings and seals. This will affect the temperature trending of the glycol loops but this is expected.

LHO VE - Wed CP1 Fill

david.barker@ligo.org — Wed, 11 Feb 2026 10:41:47 -0800

Author: david.barker@ligo.org

Report ID: 89120

Wed Feb 11 10:11:01 2026 INFO: Fill completed in 10min 58secs

Images attached to this report

H1 CDS - All models on h1sush7 stopped. Restarted models and reset HAM7 SWWD.

david.barker@ligo.org — Wed, 11 Feb 2026 10:40:31 -0800

Author: david.barker@ligo.org

Report ID: 89119

at 10:11 all the models on h1sush7 stopped with ADC timeouts. Most probably due to rack work on the Mech Rm Mez.

At 10:33 I verified that all the IO Chassis cards were visible on the bus and restarted the models. I cleared the HAM7 SWWD, it had tripped h1iopseih7.

H1 General - OPS Wednesday Day shift start

ryan.crouch@ligo.org — Wed, 11 Feb 2026 07:34:46 -0800

Author: ryan.crouch@ligo.org

Report ID: 89117

TITLE: 02/11 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: 9mph Gusts, 7mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.21 μm/s
QUICK SUMMARY:

I saw a few baby elk running together on the LIGO side of route 10 about a half mile before site
More HAM 1 checks, JAC EOM...
HAM7 pumpdown continues

LHO VE - HAM7 Pumpdown Update

gerardo.moreno@ligo.org — Tue, 10 Feb 2026 22:02:26 -0800

Author: gerardo.moreno@ligo.org

Report ID: 89116

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

Pumpdown was restarted this morning around 9:11 am local time. After pressure inside HAM7 reached 0.5 Torr we switched over to the turbo, we had a very smooth transition. After the internal pressure of HAM7 reached 5.0x10^-05 Torr all O-ring isolation valves were closed (we have one at the turbo pump, another at the chamber and one more at the relay tube).
HAM7 internal pressure after 12+ hours of pumping is 5.2x10^-06 Torr. The attached plot has a small glitch at the 10 hour mark, likely due to the DAQ restart.

Annulus ion pump update. The ion pump controller was turned on this morning, the ion pump controller struggled for some time as it was railed, but we did noticed that the pressure reading reported by the aux-cart (aux-cart remains connected and pumping on this system) dropped very slow, but after a some minutes the ion pump controller was not railed no more.

Images attached to this report

H1 IOO - RTP test beam path in the OSB optics lab (Elenna, Betsy, Jenne, Keita)

keita.kawabe@ligo.org — Tue, 10 Feb 2026 20:32:33 -0800

Author: keita.kawabe@ligo.org

Report ID: 89115

It took much longer than expected but we set up the beam path for the RTP test in the OSB optics lab.

Since more power makes it easier to see the ghost beams, I removed the beam dump that used to receive most of the red power (~530mW) and directed the beam to the front of the table (red path in the attached). I stole the steering mirror that used to be used for the low power P-pol path (circled in red). The low power p-pol path is now simply blocked. No other change was made to low power S-pol path (orange) as well as green path (green), but the beams are blocked by beam dumps. If you want to use these, simply unblock.

The beam radius will be 300~400 um or so at the location we plan to put the RTP (represented by a green rectangle in the second attachment). Elenna will post the plot of the beam size measurement.

The third picture shows the containers for different RTP. Left is the one for the crystal in HAM1. The middle seems to be from the same batch. Right looks different, on the bottom of the container there's a label saying "I/O something something 2017" so this is likely the old one.

We didn't have time to actually test the crystals, wait for tomorrow's udpate.

INS, IOO, ISC

Images attached to this report

H1 IOO - Comment to IMC beam alignment, power to HAM6 looks OK

jennifer.wright@ligo.org — Tue, 10 Feb 2026 17:34:18 -0800

Author: jennifer.wright@ligo.org

Report ID: 89114

Olli and I went in and monitored IMC-MC2 YAW while changing the JM3 mirror in pitch, I loosened the locking screws for the pitvh adjustment to make it easier to move. Moving anti-lockwise in JM3 pitch moves down in yaw on the MC TRANS QPD due to the HAM1 periscope. We overshot a bit and had to correct the opposite way.

Every step I made we waited for the WFS to converge.

Every couple of steps we offloaded the WFS.

Then once we thought we couldn't get much closer we switched to adjusting YAW on JM3 to bring the MC2 TRANS pitch nearer to 0. The steps I made in yaw of JM3 didn't have as large an effect on MC2 TRANS as pitch so this was easier to tune.

I have included a plot showing our final values, 0.04 counts for yaw and 0.01 counts for pitch.

Images attached to this report

H1 CDS - Cables staged in LVEA

filiberto.clara@ligo.org — Tue, 10 Feb 2026 17:24:34 -0800

Author: filiberto.clara@ligo.org

Report ID: 89113

Cables have been staged in front of the TCSX table enclosure on the floor. As this is a trip hazard, the area is tapped off with caution tape. Cables will be removed/pulled tomorrow.

SUS

LHO VE - Comment to HAM7 Viewport Inspection

jordan.vanosky@ligo.org — Tue, 10 Feb 2026 17:05:10 -0800

Author: jordan.vanosky@ligo.org

Report ID: 89111

Pictures of the coating blemishes.

Viewports installed on HAM7 (PN, SN, and inspection notes) are recorded in spreadsheet on E2400096. This spreadsheet only includes the viewports installed for the A+ filter cavity line (HAM& & HAM8). Future in situ viewport inspections will be recorded here as well.

Images attached to this report

X1 SUS - Four HRTS moved to the VPW for storage

ryan.crouch@ligo.org — Tue, 10 Feb 2026 16:58:37 -0800

Author: ryan.crouch@ligo.org

Report ID: 88801

On Friday, Oli and I moved four HRTSes over to their dedicated desicant cabinet in the VPW. Serial numbers 01 - H1BHDL1, 08 - H1BHDBS1, 03 - H1BHDBS2, and 04 - L1 Spare. These suspensions are locked with their wires tension relieved, the flags, magnets, magnet spacers, and BOSEMs have all been removed. We were already planning on moving them over but upon finding some corrosion on two parts we moved up that time frame. The two parts are D1900350 and D2100059, which are respectively the BOSEM Adj Mechanism Cams (12 per SUS), and the Top Mass Magnet Spacers (12 per SUS). The findings are discussed in FRS 36538 for the spacers and 36627 for the cams. I looked over and replaced the worst looking BOSEM cams before wrapping and bagging these suspensions.

We loaded them up into individual pelican cases (two at a time, there's two good pelican cases with padding), padded them as if we were going to ship them, loaded them into a site car then drove them from the staging building to the VPW. There we carefully unloaded them, brought them inside, unpacked and transfered them to the desicant cabinets. We did this twice for four total suspensions.

Images attached to this report

H1 CDS - Comment to CDS Maintenance Summary: Tuesday 10th February 2026

david.barker@ligo.org — Tue, 10 Feb 2026 16:46:27 -0800

Author: david.barker@ligo.org

Report ID: 89109

Tue10Feb2026
LOC TIME HOSTNAME MODEL/REBOOT
11:28:08 h1oaf0 ***REBOOT*** <<< Power cycle of h10af0 to upgrade to 20bit-DAC

11:29:51 h1oaf0 h1iopoaf0 <<< new iop model
11:30:04 h1oaf0 h1pemcs <<< new pem model
11:30:17 h1oaf0 h1tcscs
11:30:30 h1oaf0 h1susprocpi
11:30:43 h1oaf0 h1seiproc
11:30:56 h1oaf0 h1oaf
11:31:09 h1oaf0 h1calcs
11:31:22 h1oaf0 h1susproc
11:31:35 h1oaf0 h1calinj
11:31:48 h1oaf0 h1bos

11:38:10 h1daqdc1 [DAQ] <<< 1-leg restart
11:38:22 h1daqfw1 [DAQ]
11:38:23 h1daqtw1 [DAQ]
11:38:24 h1daqnds1 [DAQ]
11:38:31 h1daqgds1 [DAQ]
11:44:32 h1daqgds0 [DAQ] <<< 0-leg restart
11:44:39 h1daqfw0 [DAQ]
11:44:39 h1daqtw0 [DAQ]
11:44:40 h1daqnds0 [DAQ]

H1 CDS - CDS Maintenance Summary: Tuesday 10th February 2026

david.barker@ligo.org — Tue, 10 Feb 2026 16:41:35 -0800

Author: david.barker@ligo.org

Report ID: 89108

WP13018 Upgrade h1oaf0 18bit-DAC to 20bit-DAC

Fil, Oli, Anamaria, Robert, Ryan S, EJ, Dave:

We replaced the first DAC in h1oaf0 (a 18bit-DAC) with a 20bit-DAC. We reused the IO Chassis ribbon cable and Interface card, they are identical for these types of DAC.

This DAC is only being used by the PEM model.

A new h1iopoaf0 model was installed with the DAC change, its INI file was not changed.

A new h1pemcs model was installed with several changes:

. All 8 DAC channels are now being driven (previously last channel was not driven)

. An excitation stage was added to the model, a copy from LLO's PEM models. This comprises two Oscillators and a Noise_generator (see medm below)

. An additional DACOUTF filter bank as added just prior to the DAC part, each with a x4 filter in the FM10 slot.

A DAQ restart was required.

18bit-DAC (removed)	101208-66
20bit-DAC (installed, originally in h1susb123)	210303-49

Attached image shows H1PEM_CS_DAC_DRIVES_CUST.adl MEDM which maps the excitation path from OSC/NOISE_GEN through the filters for each DAC channel. Note on DACOUTF, each FM10 has a 20BitDAC filter, which is a x4 gain.

As an example, image shows chan0 being driven by a 0.1Hz sine wave with amp=1.0. The image is caught when the input is 0.988, but the DAC_chan0 drive is 3.953.

Recovery of PSL camera images.

Fil, Corey, Dave:

Following the replacement of camera power supplies, I recovered the PSL cameras and quad video server images.

DAQ Restart

Dave:

The DAQ was restarted for the h1pemcs model change. There were no problems with this restart.

Images attached to this report

LHO VE - HAM7 Viewport Inspection

gerardo.moreno@ligo.org — Tue, 10 Feb 2026 16:37:14 -0800

Author: gerardo.moreno@ligo.org

Report ID: 89107

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

We inspected all the viewports currently installed on HAM7, inspection was done to verify the serial number on the viewports or viewport assembly.
Most viewports passed visual inspection, however we did note that one viewport assembly on port A2F3 has some blemishes, they are located on the glass of the assembly on both, air and vacuum side. We asked others for a second opinion, we decided to leave current viewport assembly in place and replace it on the next vent. This particular viewport was inspected "recently" by others, see aLOG entry.

-Y door viewports:
Port A1F2 a ZV-800 serial number R144, nothing noted.
Port A1F1 a ZV-800 serial number R134, nothing noted.

+Y door viewports;
Port A2F1 has a ZV-800 serial number R146, nothing noted.
Port A2F2 has a ZV-800 serial number R109, nothing noted. Side note, this viewport has a AR1064 coating.
Port A2F3 has a D1100999, high quality non-wedged 6" viewport. Serial number 011. Some blemishes on the air side of the glass, located around 12 O'clock. Blemishes vacuum side of the glass, located around 2:30 to 3:30 O'clock.
Port A2F4 has a D1100999, high quality non-wedged 6" viewport. Serial number 022, nothing noted.

H1 IOO - IMC beam alignment, power to HAM6 looks OK

sheila.dwyer@ligo.org — Tue, 10 Feb 2026 16:32:29 -0800

Author: sheila.dwyer@ligo.org

Report ID: 89106

Jenne Drigger, Sheila Dwyer, Jennie Wright and Oli in chamber

The IMC guardian is now working when we put 3W into HAM1. Jenne held the output of MC2 M1 length drive, because that has not been working. We also edited the ISC_library is_locked(IMC function), by lowering the threshold used when the input power is above 2W. Since the IMC transmission has since improved it could probably be put back.

We engaged the WFS DOF1+2 which use MC refl WFS, and offloaded them. We then saw that we are well off center in MC2 trans P + Y, which were well centered on our reference time of 11:25 UTC Dec 3rd.

Jenne Driggers moved the IMs to match the top mass osems to the values from 89068. We also noticed that the whitening gain on IM4 trans was changed to 0Db (should be 18dB), making the power seem low in 89046.

	Dec3	now
power into HAM1	2W	3W (plus 30% loss on JM3)
MC2 trans sum	310 counts	200-250 counts	80%
IM4 trans NSUM (power into PRM)	1.8W	fluctuating between 1W-3W	1.45W expected
AS_C in single bounce		3-4mW	1.450.030.25*0.3 = 3.3mW into HAM6
IM4 trans pit	0.23
IM4 trans yaw	-0.04

Jennie and Oli are still working in chamber, so these numbers are still changing.

H1 CAL - Comment to PCAL EX Endstation measurement

anthony.sanchez@ligo.org — Tue, 10 Feb 2026 16:32:28 -0800

Author: anthony.sanchez@ligo.org

Report ID: 89105

Obligitory before and after beam spot pics.

The problem we saw on measurement #7 where we saw a gap in the data was a DAQ restart which cuased the H1:CAL-INJ_MASTER_SW to turn back on. Which then caused H1:CAL-INJ_MASTER_OUTPUT so have a signal. So in the future if we see something like that again we should check the status of those CAL Line Injection switches before continuing again, as it apparently may increase our error bars.

Images attached to this report

Non-image files attached to this report

Sosb-office26021013320-1.pdf

LHO General - Tues DAY Ops Summary

corey.gray@ligo.org — Tue, 10 Feb 2026 16:31:08 -0800

Author: corey.gray@ligo.org

Report ID: 89097

TITLE: 02/10 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

JAC team worked on two fronts (one group in the optics lab getting a set up for measurements for the eom crystal and the other to do alignment work in HAM1). HAM7 continues the pumpdown. There was a DAC upgrade for OAF0 (in the morning Dave [remotely] will need to finish one task here which should NOT require a DAQ restart).
LOG:

1538-1919 "test-pitching" of BSC2 cleanroom tent (randy)
- Using West Crane for more lighting
1612-1728 LVEA technical cleaning (kim)
1622 Large bull elk spotted outside near route 10 next to the solar panel on the other side of the street from the LHO sign by Mitch. Dolly snapped some awesome photos of them (attached).
1634-1642 Checking on Annulus Ion Pump (jordan)
1656-1946 Restarting HAM7 pumping (gerardo, jordan)
- 1740-1847 travis joining
1710-1730 PSL Power Supply for cameras (fil, marc)
- This did NOT take the laser down! :)
1715 OAF0 model up + daq restart around 11am (dave)
- 1715 Dave teamspeaked in about sound noise at EY---no one was out at EY (this came up via a signal on CDS Overview)
1726 BS ISI WD trip (most likely due to the "Tent" set-up). Re-isolated at 2014.
JAC Team had meeting this morning & splitting into 2-teams (one looking at crystal in Optics lab and another working on locking the IMC)
1741 Looking at JAC eom crystal in optics (keita, jenne, betsy)
- 1858 elenna working with Keita (to spell jenne & betsy)
- 2002 Keita/Elenna out for lunch
1745-1800 Opening PSL light pipe in prep for JAC (sheila, jennie)
1745-2107 EX PCal measurements (tony, dripta)
1800 Richard out to chat with travis
1810-1908 EY technical cleaning (kim)
1813-1838 Parts search at optics lab & ham1/lvea (camilla, elenna)
1833 PCal team takes ETMx from MISALIGNED -> ALIGNED (dripta)
1834-2153 Warming up FARO for measurements at BSC2 (jason)
- 1910 Then Jason needs to help out at HAM1...and will return to FARO work
1909-2054 JAC team heading out to HAM1 (jennie, jason, oli)
1910-1950 OAF0 18bit to 20bit daq upgrade in CER. This will cause chillers to be down for 30min. Then power back up OAF0 computer in MSR. Then DAQ restart.
- 1940 Turned off TCS Chillers & turned back on at 1950 (camilla, corey)
- After DAQ restart, restarted ndscopes in the control room.
1924-2140 Checking on FARO warm-up (ryanc)
- 2026 heading back out to check on it
2034-2220 JAC crystal measurements continue (keita)
2121 Cable pulling around HAM3/6 (marc, fil)
2153 Set-up for SPI in the optics lab (jeff)
2307 Alignment work on HAM1 (jennie, oli)
2307 JAC crystal measurements (keita, elenna)
2352-0010 Checking on cable pulling (richard)

Images attached to this report

H1 ISC - Comment to IMC cavity axis now vs pre-vent

jenne.driggers@ligo.org — Tue, 10 Feb 2026 15:59:57 -0800

Author: jenne.driggers@ligo.org

Report ID: 89104

Since the IMC is nicely locked, and we're only seeing 0.2 W on IM4 trans at a time when we expect ~1W, I moved the IM1, IM2, and IM3 to these positions. Still not very much on IM4_Trans.

H1 SEI - Setting Lens Position for SPI In-vac SuK Fiber Collimator Beam Profile: No Systematic Error; Waist Position is just extremely Sensitive to Lens position

jeffrey.kissel@ligo.org — Tue, 10 Feb 2026 13:17:15 -0800

Author: jeffrey.kissel@ligo.org

Report ID: 89099

J. Kissel, S. Koehlenbeck Executive Summary: after some more modeling of the beam profiles from LHO:89047, we identify that there's nothing fundamentally wrong in the analysis -- it's just that the out-going waist position of the beam exiting the SPI fiber collimators is just *extremely* sensitive to lens position -- to the tune of z_lens = 11 [mm] +/- 50 [um] can swing the waist position z0 = +/- 1.5 [m], and that makes it extremely challenging to set the waist at z0 = 0.0 [m] with out a better measurement setup/method for adjusting the position. The full story: Trying to better understand the results from LHO:89047, in this aLOG I: (0) Verified Beam Profile Fit with JAMMT instead of A La Mode: Imported the beam profile data from each laser into JaMMT, with the z-axis inverted (i.e. z = [-5.41, -4.496, ... , -0.508] [m]), and confirmed that JaMMT agrees with a la mode in terms of waist radius, w0, and waist position, z0 -- except now with the beam "incoming" into the collimator/lens/fiber. The fit predicts a waist w0 at position z0 of JaMMT A La Mode (Matlab) w0y' w0x' w0x w0y (assume w0x = w0y', w0y = w0x') OzOptics = (0.7041, 0.6766) [mm] (0.7040, 0.6766) [mm] AxcelPhotonics = (0.6807, 0.7048) [mm] (0.6807, 0.7049) [mm] at position z0y' z0x' z0x z0y (assume z0z = z0y', z0y = z0x') OzOptics = (-1.4940, -1.5840) [m] (1.4940, 1.5837) [m] AxcelPhotonics = (-1.5803, -1.4870) [m] (1.5803, 1.4869) [m] where -- you're reading that right, it's not a copy and paste error -- the difference between the matlab fit and jammt fits are at the \delta(w0) = 0.1 [um] and \delta(z0) = 0.1 [mm] level (though for some silly reason the convention of which is the x and y dimension is flipped between the two fitting programs). This reconfirms/is consistent with LHO:89047 fit of data and their statement that the waist radius, w0 = 0.6915 +/- 0.015 [um] at z0 = 1.5362 +/- 0.053 [m] See GREEN boxed answers in attached screenshots of OzOptics and AxcelPhotonics JaMMT sessions (1) Found Mode Field Diameter inside Fiber: Used each of those JaMMT sessions with imported / fit beam profile from both lasers (in the fiber collimator's current lens position) to model the mode field diameter of the fiber (thus validating the SPI conceptual design Slide 60 of G2301177 calculation MFD = 7.14 [um]). To do so, we install the f = 11 [mm] focal length lens at z = 0.0 mm -- i.e. finding the new beam parameters "down stream" (in the +Z direction, "in towards the fiber") post-lens assuming a f = 11 [mm] focal length lens placed at the ideal position. In JaMMT speak, we add a substrate that's a thin lens at position 0.0 [m], with aperture 5.5 [mm], and focal length 0.011 [m]. As can be seen in RED, the now-augmented OzOptics and AxcelPhotonics JaMMT sessions, inserting the fast lens dramatically increases the beam radius (+z of the lens, the red beam extends out as essentially vertically off the scale); which is indicative if really high divergence of the free-space beam as it is mode-matched into the fiber. Said in the direction of our experiment -- the beam coming from the fiber is highly divergent (extremely small waist radius in the fiber), and the fast lens brings the outgoing free-space beam "in check" dramatically reducing the beam divergence, i.e. "collimating" it. The JaMMT fit results remain in terms of radius, w0, but to distinguish this in-fiber waist radius from the free-space waist radius, I'll call these the Mode Field radii, MFw0. Those results are MFw0y', MFw0x' OzOptics (3.589 , 3.717) [um] @ MFz0y' = MFz0x' = 0.011 [m] AxcelPhotonics (3.597 , 3.726) [um] @ MFz0y' = MFz0x' = 0.011 [m] Note the order of magnitude on the units -- microns, not millimeters. Also note that the fit for position of the waist is 0.011 [m], or 11 [mm] for all four waist radius data points (to the precision of the display). This matches the ideal/expectation -- that we *want* the f = 11 [mm] lens to focus the free space beam down to the size of the waist of the beam in the fiber core, and to have that waist 11 [mm] away from the lens. In terms of diameter, that's MFDy', MFDx' OzOptics (7.1780, 7.4340) [um] AxcelPhotonics (7.1940, 7.4520) [um] This modeled MFD based on the out-going beam measurement, MFD_mean = 7.3145 +/- 0.1487 [um] is within 2.5% of the expected value for the MFD = 7.14 [um]. from a core radius of a = 2.75 [um], and *fiber* numerical aperture, NA = 0.12. (I was wrong to suggest that we might have needed to use the NA from the fiber collimator. Sina was right to use the NA of the optical fiber.) And just to hit that "highly divergent" point home, turning the mode field radii into a Rayleigh range [with MFzR = pi * (MFw0^2) / \lambda]: that's MFzR_mean = 39.49e-6 [m] as opposed to the collimated free-space beam that has a range of ~3.25 [m]. (2) Re-create the real system as a function of lens position With that modeled mode field diameter (radii) in the fiber, we can restart JaMMT with those initial beam parameters, but the position of the waist at z0 = 0.0 [m] rather than the +0.011 [m] we found from Step (1). This changes our frame of reference -- we now assume we know the field waist coming out of the fiber, and we position that field waist, MFz0 = -0.011 [m] behind the lens, and we're trying to *create* a collimated beam with the f = 11 [mm] lens, with a new waist at z0 = 0.0 [m]. In JaMMT speak, we (a) Reset and Clear Plot, then Edit the Initial Beam to have w0 z0 tangential w0 tangential w0 wavelength MFw0y' MFw0x' [um] [m] [um] [m] [nm] OzOptics 3.589 0.0 3.717 0.0 1064 AxcelPhotonics 3.597 0.0 3.726 0.0 1064 (b) Add a substrate; a thin lens, at position z = 0.011 (for now), with aperture 5.5 [mm], and focal length 0.011 [m]. (c) Add beam analyzers at each z position point of the originally measured vector, z = [0.508 0.991 1.499 2.007 3.251 4.496 5.41] [m] The results of (a) and (b) create the screenshots OzOptics and AxcelPhotonics, which show that with the lens at *exactly* z = 0.011 [m], or z = 11 [mm], that puts the waist at z_lens = 0.011 [m] ( w0x , w0y ) @ (z0x, z0y) [mm] [mm] [mm] [mm] OzOptics 1.0830 , 1.0023 22 22 AxcelPhotonics 1.0357 , 0.9999 22 22 This confirms that the original guess of the waist radius written in the assembly procedure of w0 = 1.05 +/- 0.1 [mm] when setting the lens position to have the waist position z0 = 0.0 [m], and thus a Rayleigh Range, zR = 3.25 [m] was not wrong at all. After adding in the analyzers (c), you get displays that look like OzOptics and AxcelPhotonics, from which you can read off the model of what the measured beam profile should ideally be. (3) Model/Discover just how sensitive beam profile of the out-going beam is to lens position: positioning needs to be accurate within 50 [um] (ridiculous!). Now, nudge the z position of the beam splitter in each data set until you reproduce the beam you measured / fit in Step 0. I find that a lens position of z = 0.011045 [m] = 11.045 [m] = 11 [mm] + 45 [um] reproduces a real focus that matches the beam profiles we measured and waist radius and position we fit consistent with w0 = 0.6915 +/- 0.015 [um] at z0 = 1.5362 +/- 0.053 [m]. 45 [um]!! A lens position 45 [um] the other way, z = 11 [mm] - 45 [um] = 0.10955 [m] pushes the waist position ~ 1.5 [m] behind the lens (z0 = ~ -1.5 [m]), i.e. it creates a virtual focus. See OzOptics z_lens = nom + 45 [um] OzOptics z_lens = nom - 45 [um] AxcelPhotonics z_lens = nom + 45 [um] AxcelPhotonics z_lens = nom - 45 [um] I conclude from this that with the existing measurement setup and great lack of precision in adjustability of the lens position, it's no wonder we ended up with a waist position off by 1.5 [m]. For the record, with the (OzOptics, AxcelPhotonics) laser's data set, to get the waist position z0 to actually be at 0.0 +/- 0.005 [m] ***, you need the lens position to be z_lens = (10.9997, 10.99969) [mm] = 11 [mm] - 0.3 [um]. Just ridiculous. *** Since the beam is a bit astigmatic, you can only model one axis to be exactly z0 = 0.0 at a time, so the 5 [mm] uncertainty covers the z0y position when you set the z0x to 0.0 [m]. After corroborating all of this with Sina, she's not surprised. In fact, she was more surprised when I claimed that collimating the beam was easy back in Jun / Aug of 2025. (4) Sina and I conclude the best hope we have is to (a) Don't worry about having the position of the collimator within the collimator adapter ring be as shown in T2400413. What's critical is that the alignment of the outgoing beam doesn't change in between lens position iterations. (b) Instead of entirely backing off the 2x tiny set screws that hold a given lens position, back off only 1x to try to reduce the freedom of the lens position a bit to hopefully increase the precision of the adjustment (c) Set up a measurement system the measures and fits the beam position at multiple points with rapid iteration (d) Change the density of measured z position points to get more near the collimator (e) If you *must* measure the beam diameter / adjust the lens position at one position -- do it near the collimator, rather than past the Rayleigh Range. But also, see steps (c) and (d). CSWG, ISC, SEI

Images attached to this report

H1 CAL - PCAL EX Endstation measurement

dripta.bhattacharjee@ligo.org — Tue, 10 Feb 2026 13:03:33 -0800

Author: dripta.bhattacharjee@ligo.org

Report ID: 89103

Tony and myself are here at EX finishing up the EX ES measurement.
We did find that the excitations were turned on at GPS time: 1454787583, but no excitations came through the channel PCAL_EX_SUM_MON until after we were finished.
We did however have to restart a measurement due to a gap in the data. measurement #7 Both beams on the Working standard inside the RX module.
What we did not realize until after, was that at the time the gap happened the excitation switch INJ_MASTER_SW was turned back on and remained on for the remainder of the measurement.

Also Note:
PCAL laser here at End X is shuttered inside the TX module. The shutter control is turned to Local and intentionally closed, because we have stolen the RX sensor for lab measurements.

anthony.sanchez@cdsdell428: python generate_measurement_data.py --WS PS4 --date 2026-02-09
Reading in config file from python file in scripts
../../../Common/O4PSparams.yaml
PS4 rho, kappa, u_rel on 2026-02-09 corrected to ES temperature 299.7 K :
-4.701132373259706 -0.0002694340454223 2.8588448124243135e-05
Copying the scripts into tD directory...
Connected to h1daqnds1
martel run
reading data at start_time: 1454784870
reading data at start_time: 1454785410
reading data at start_time: 1454785815
reading data at start_time: 1454786310
reading data at start_time: 1454786835
reading data at start_time: 1454787210
reading data at start_time: 1454787660
reading data at start_time: 1454788220
reading data at start_time: 1454788740
Ratios: -0.46019480202307234 -0.46642274644534126
writing nds2 data to files
finishing writing
Background Values:
bg1 = 9.788561; Background of TX when WS is at TX
bg2 = 4.347145; Background of WS when WS is at TX
bg3 = 9.849034; Background of TX when WS is at RX
bg4 = 4.403818; Background of WS when WS is at RX
bg5 = 9.795756; Background of TX
bg6 = 0.716216; Background of RX

The uncertainty reported below are Relative Standard Deviation in percent

Intermediate Ratios
RatioWS_TX_it = -0.460195;
RatioWS_TX_ot = -0.466423;
RatioWS_TX_ir = -0.454775;
RatioWS_TX_or = -0.461187;
RatioWS_TX_it_unc = 0.087118;
RatioWS_TX_ot_unc = 0.081615;
RatioWS_TX_ir_unc = 0.080454;
RatioWS_TX_or_unc = 0.079252;
Optical Efficiency
OE_Inner_beam = 0.988331;
OE_Outer_beam = 0.989282;
Weighted_Optical_Efficiency = 0.988806;

OE_Inner_beam_unc = 0.054963;
OE_Outer_beam_unc = 0.053369;
Weighted_Optical_Efficiency_unc = 0.076611;

Martel Voltage fit:
Gradient = 1636.958979;
Intercept = 0.082747;

Power Imbalance = 0.986647;

Endstation Power sensors to WS ratios::
Ratio_WS_TX = -1.079194;
Ratio_WS_RX = -1.393794;

Ratio_WS_TX_unc = 0.051228;
Ratio_WS_RX_unc = 0.200042;

=============================================================
============= Values for Force Coefficients =================
=============================================================

Key Pcal Values :
GS = -5.135100; Gold Standard Value in (V/W)
WS = -4.701132; Working Standard Value

costheta = 0.988362; Angle of incidence
c = 299792458.000000; Speed of Light

End Station Values :
TXWS = -1.079194; Tx to WS Rel responsivity (V/V)
sigma_TXWS = 0.000553; Uncertainity of Tx to WS Rel responsivity (V/V)
RXWS = -1.393794; Rx to WS Rel responsivity (V/V)
sigma_RXWS = 0.002788; Uncertainity of Rx to WS Rel responsivity (V/V)

e = 0.988806; Optical Efficiency
sigma_e = 0.000758; Uncertainity in Optical Efficiency

Martel Voltage fit :
Martel_gradient = 1636.958979; Martel to output channel (C/V)
Martel_intercept = 0.082747; Intercept of fit of Martel to output (C/V)

Power Loss Apportion :
beta = 0.998895; Ratio between input and output (Beta)
E_T = 0.993838; TX Optical efficiency
sigma_E_T = 0.000381; Uncertainity in TX Optical efficiency
E_R = 0.994937; RX Optical Efficiency
sigma_E_R = 0.000381; Uncertainity in RX Optical efficiency

Force Coefficients :
FC_TxPD = 7.890432e-13; TxPD Force Coefficient
FC_RxPD = 6.178607e-13; RxPD Force Coefficient
sigma_FC_TxPD = 5.070187e-16; TxPD Force Coefficient
sigma_FC_RxPD = 1.259006e-15; RxPD Force Coefficient
data written to ../../measurements/LHO_EndX/tD20260210/

Images attached to this report

Non-image files attached to this report

LHO_EndX_PD_ReportV5.pdf

LHO VE - Tue CP1 Fill

david.barker@ligo.org — Tue, 10 Feb 2026 12:12:15 -0800

Author: david.barker@ligo.org

Report ID: 89102

Tue Feb 10 10:11:14 2026 INFO: Fill completed in 11min 11secs

Images attached to this report

H1 ISC - PSL +/-12V Kepco Supply Replacement (Dome Camera Supply)

marc.pirello@ligo.org — Tue, 10 Feb 2026 10:40:30 -0800

Author: marc.pirello@ligo.org

Report ID: 89101

We replaced the failed +/-12V Kepco supplies in VDD-C6 U34 which power the PSL dome cameras
U34_LHS: +12V supply S1201947 removed due to failed fan, replaced with upgraded supply S1202017
U34_RHS: -12V supply S1201992 removed due to failed fan, replaced with upgraded supply S1300289

F. Clara, M. Pirello

PSL

H1 ISC - Turned off HV for HAM7

marc.pirello@ligo.org — Tue, 10 Feb 2026 10:27:43 -0800

Author: marc.pirello@ligo.org

Report ID: 89100

We turned off the HV bypass for upcoming HAM7 pump down. The power is located in the racks on the Mezannine in the Mechanical Room.

We followed Fil's instruction by first turning off the 24V for the interlock chassis, followed by removal of the bypass from the interlock chassis and then switching off the SQZ_PZT power. Finally I switched off the SQZ_TTFSS power, so that all high voltage is off.

We reconnected the pressure sensor while we were there in place of the bypass.

M. Pirello, G. Moreno, J. Vanosky

ISC

LHO VE - HAM7 Pumpdown

gerardo.moreno@ligo.org — Tue, 10 Feb 2026 08:00:51 -0800

Author: gerardo.moreno@ligo.org

Report ID: 89098

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

Yesterday after inspecting the viewports on the +Y door, the pumpdown was started. The annulus was first, no issues with the pumpdown, pressure dropped nominally, indicates a good seal on the -Y door, then the main volume was blown down, dew point at -24.9 degrees C. Main volume was pumped for about 1 hour and 40 minutes, taking the pressure down to 33.4 Torr, then pumpdown was stopped for the night. We will continue with the pumpdown this morning.

Note, the cleanroom fans were turned off yesterday after the viewport inspection.

Images attached to this report

LHO General - Tues DAY Ops Transition

corey.gray@ligo.org — Tue, 10 Feb 2026 07:43:40 -0800

Author: corey.gray@ligo.org

Report ID: 89096

TITLE: 02/10 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: 9mph Gusts, 6mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.47 μm/s
QUICK SUMMARY:

HAM1 JAC investigation work will continue. Randy is testing out the new BSC2 Cleanroom Tent. LVEA continues in unique Bifurcated Laser Safe state.

Happy -Eve- of the10-year Anniversary of GW150914 Announcement!

H1 IOO - Comment to Checking EOM crystal

masayuki.nakano@ligo.org — Tue, 10 Feb 2026 07:20:40 -0800

Author: masayuki.nakano@ligo.org

Report ID: 89095

The beam after the second lens is actually not diverging. According to this plot, we suppose to be able to find the splitted beams in the IOT2 table.

Images attached to this report

H1 IOO - Comment to Checking EOM crystal

keita.kawabe@ligo.org — Mon, 09 Feb 2026 17:40:05 -0800

Author: keita.kawabe@ligo.org

Report ID: 89092

Very rough power estimate for the ghost beam(s) is ~O(1%)

Jennie and Jason set up another temporary iris between JM2 and JM3, centered it with 1W into HAM1 to carefully block the ghost beams without blocking the main beam, then changed the power to 100mW (for safety) and measured the power at various places. Measurement accuracy cannot be great (Jennie and Jason says the numbers were jumping around as it was difficult to hold the power meter head at a fixed position mid-air) but I would say the power in the ghost beams is ~O(1%).

JAC out	~105mW
Between JM2 and the iris (includes wrong-pol beam)	104~105mW
After the iris (wrong pol as well as ghosts blocked)	99~100mW
Wrong-pol beam	1~3mW
Background light (no beam)	1~2uW

Where do they go?

After opening the temporary iris that we just put in all the way, the iris just downstream of JM3 was already blocking some of the ghost beams as well as the wrong polarization beam (JM3iris.jpg). Vertical beams don't look vertical because the iris is not a flat plane and we have a large parallax here. Anyway, it seems that we can block further if we want to from the top and the bottom.

The picture of the last iris on HAM1 shows that something is blocked on the left (+Y) side (outputiris.jpg). Looks like the iris is clipping something on the right but the camera couldn't be positioned to have a good view for both sides.

The last picture (after_last_iris.jpg) shows the beam right after the last iris on HAM1. You can see that some ghost beams are still coming through.

With this beam injected into HAM2 and misaligning MC2, we looked into IOT2L to see the MC REFL beam. We weren't able to find ghost beams there, though Jason and I felt that the beam is not super clean.

One question Jason had was whether or not the diverging beams that originate from the EOM location are supposed to keep diverging after lenses.

INS, IOO, ISC

Images attached to this report

H1 CDS - h1sush7 timing glitch, models restarted

david.barker@ligo.org — Mon, 09 Feb 2026 17:14:14 -0800

Author: david.barker@ligo.org

Report ID: 89094

Sheila, Camilla, Jim, EJ, Dave:

At 16:29:25 we had a timing glitch on h1iopsush7 which stopped it from running.

Sheila and Camilla checked the SDF settings for h1susfc1 and h1sussqzin models before the restarts.

I verified all the IO Chassis cards were present and correct, and then restarted all the models.

I untripped the HAM7 SWWD, but accidentally also untripped HAM1. I returned HAM1 back to PM1 bypassed, SEI-HAM1 tripped.

Images attached to this report

H1 SQZ - SUSSQZIN and SUSFC1 SDFs before restart

sheila.dwyer@ligo.org — Mon, 09 Feb 2026 16:59:36 -0800

Author: sheila.dwyer@ligo.org

Report ID: 89093

Dave has to restart SUS SQZ in and SUS FC1. Camilla and I went through the SDF files and accepted all the current sliders.
We also saw that the OPO T damp gain was changed, we did not accept that.

Images attached to this report

LHO General - Mon Day Ops Summary

corey.gray@ligo.org — Mon, 09 Feb 2026 16:30:09 -0800

Author: corey.gray@ligo.org

Report ID: 89080

TITLE: 02/09 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

HAM7 had viewports inspected and steps initiated for pumping down. JAC team spent a good part of the day inspecting the in-vac EOM output beam. The ACCESS SYSTEM computer had its network issues fixed (for Access System & cameras).
LOG:

1531-1547 Optics lab clean (kim)
- 1703-1803 Return for main cleaning in lvea (kim)
- 1803-1859 Picking up garb at Receiving and cleaning our buggy MidY (kim)
- 1900-1931 MX cleaning (kim)
1733-1756 Looking for ground seismometer at end stations (jim)
1825-1945 HAM7 Annulus Ion Pump (AIP) pumping begins (gerardo)
- 1941-1945 Jordan joining
1837-2050 JAC EOM checks (jennie, jason)
- 1843-2044 Keita joining
1847-1913 HAM3 taken to ISI_DAMPED_HEPI_OFFLINE (from ISOLATED) to allow crawling around the chamber to look at feedthrus (jim, betsy)
- Jim out and HAM3 returned to ISOLATED. Betsy working with Travis.
1851 HAM3 + HAM7 AIP pumpdown checks (travis)
2000-2008 increasing PSL power for JAC (ryanS)
- 2019 another adjustment (RyanS)
2117 VAC team return to work on HAM7 for AIP pumpdown, viewport inspection, chamber pumpdown (travis, gerardo, jordan)
- 2342 Travis out
2139 Out to HAM7 (betsy,richard)
2203--0025 Back to HAM1 for JAC EOM checks (keita, jason, jennie)
- They mentioned issues with one of the platforms at HAM1 to Richard.
2207-2315 Checking VAC cable at EX (marc)
2250 Organizing parts in optics lab (camilla)
2233 swapping spheres in PCal Lab (tony)
2353 Dropping parts off at MY (travis)
2357-0012 Maggie giving a tour to intern applicant
0012-0019 Rack photos (oli)
0025 VAC team (gerardo,jordan) preparing for roughing pump at HAM7.
- I confirmed that the picomotor "Squeezer Things" are DISABLED via picomotor medms.

H1 ISC - Comment to EX Ion Pump X-8 Scanned

marc.pirello@ligo.org — Mon, 09 Feb 2026 16:19:54 -0800

Author: marc.pirello@ligo.org

Report ID: 89091

Cable length is ~250m, assuming cable speed of about 0.5C. Ignore every reflection after 250m.

Reflection marking end of cable is 130m from launch -10m for launch = 120m

Speed of cable = 120m/250m = 0.48C

First reflection in cable is at (73m-10m)*0.48 = 30.24m There is likely a defect in the cable at this point due to the magnitude of the reflection here.

H1 ISC - EX Ion Pump X-8 Scanned

marc.pirello@ligo.org — Mon, 09 Feb 2026 15:42:19 -0800

Author: marc.pirello@ligo.org

Report ID: 89090

Per WP13021

I have scanned the disabled SHV cable from EX Ion Pump X-8. Using a 10' launch cable, on DTF setting, with bandpass set from 10MHz to 50MHz.

The attached plot is from the scan., the following aberations appeared on the cable run:
73m = 1st interface/reflection
130m = 2nd interface/reflection
361m = 3rd interface/reflection
456m = 4th interface/reflection

There were no other reflections beyond 456m. All scans were done at C=1.

M. Pirello, G. Moreno

ISC

Images attached to this report

H1 IOO - Checking EOM crystal

jennifer.wright@ligo.org — Mon, 09 Feb 2026 14:12:18 -0800

Author: jennifer.wright@ligo.org

Report ID: 89088

Jennie W, Jason O, Keita K.

As reported in this alog (#89073) from Masayuki and Keita, after we turned the power in HAM1 up to 1W we found a series of vertically spread ghost beams aroubnd the main beam after the EOM and before JM3.

These could not be removed by translating, yawing or pitching the EOM position relative to the beam. It was decided in a larger meeting with EOM design personnel that we would first check if the crystal was cracked or damaged anywhere in case this is the cause.

First photo shows the EOM from above, using a green torch to illuminate the beam path. I can't see any scatter from defects or cracks in the crystal.

Second photo shows possibly a chip at the corner, but this should not affect the beam as its right at the edge.

Third and fourth show side view with illumination from the top at an angle.

In summary we did not see any 'smoking gun' to cause these ghost beams.

ISC

Images attached to this report

H1 SQZ - Comment to Recabling OPO in HAM7

camilla.compton@ligo.org — Mon, 09 Feb 2026 13:51:49 -0800

Author: camilla.compton@ligo.org

Report ID: 89089

Cable removed was D1700438-V2-00-S2101231

X1 SUS - BBSS Put in Can

ibrahim.abouelfettouh@ligo.org — Mon, 09 Feb 2026 12:04:45 -0800

Author: ibrahim.abouelfettouh@ligo.org

Report ID: 89087

Randy, Ibrahim

Randy and I put the BBSS in the can today, as shown by pictures.

Following LLO's advice from their experiences in alog 79950, we were able to use the aluma lift to can the BBSS. What we did in order:

1. Strip locked-mass BBSS of all cables, check for looseness, bring alum-a-lift into position to lift BBSS from lifitng bars

2. Undo dog clamps to let lift take suspension load, ensure suspension is secured on the lift. Move BBSS out of test stand - as LLO said, very small clearance.

3. Prepare temporary platform for lift fork adjustment

4. Set BBSS on temporary platform - this part was successful but needed extra blocks to avoid interference with Y-bracks on the Lower Structure.

5. Adjust forks to be allow for canning without bottoming out, relift.

6. Put into wiped-down can and check for looseness. Rewipe, check for particulate and ensure secure fit

7. Close doors.

See pictures below.

Images attached to this report

H1 PSL - PSL 10-Day Trends

ryan.short@ligo.org — Mon, 09 Feb 2026 11:26:56 -0800

Author: ryan.short@ligo.org

Report ID: 89086

FAMIS 31124

FSS has been on and off over the past week and the PZT has been swept several times for JAC install work, but otherwise not much to report this week.

Images attached to this report

LHO VE - Mon CP1 Fill

david.barker@ligo.org — Mon, 09 Feb 2026 10:16:59 -0800

Author: david.barker@ligo.org

Report ID: 89085

Mon Feb 09 10:10:47 2026 INFO: Fill completed in 10min 44secs

Images attached to this report

H1 IOO - Comment to Vertical splited beam investigation

keita.kawabe@ligo.org — Mon, 09 Feb 2026 09:23:20 -0800

Author: keita.kawabe@ligo.org

Report ID: 89084

Curoius thing about the EOM dimensions

Crystal length L=40mm, thickness T=4mm=L/10, wedge angle w=2.85 deg, and tan(2w) = 0.09981 ~ 1/10.

Though this is probably not related to the ghost beams in PIT direction, when the beam is perfectly aligned with the EOM (i.e. the light traveling the center of the crystal), the internal AR reflection of at the output face of the crystal hits the side of the crystal and the specular reflection will hit the input surface of the crystal and almost exactly comes back on top of the main beam with only 0.0272mm offset. See the 1st cartoon.

Note that the side surfaces are not polished (though the AOI is 84.3 deg so most of the power is reflected back into the crystal due to total internal reflection).

If you displace the beam in horizontal direction, the AR path is displaced in the opposite direction by about the same amount (i.e. if the main beam moves by 0.5mm toward the short face of the crystal, the AR-side-AR beam moves by about 0.5mm toward the long face). If you continue tracing the AR-side-AR beam, it turns out that the AR-side-AR-AR-side-AR beam will come back exactly on the main beam. See the 2nd cartoon (which is actually to scale, the main beam is off by 0.5mm and the 1st ghost is off by 0.5272 in the opposite direction, and the 2nd ghost is on top of the main beam).

Interesting design choice.

Images attached to this report

LHO General - Comment to Mon Day Ops Transition

corey.gray@ligo.org — Mon, 09 Feb 2026 08:49:37 -0800

Author: corey.gray@ligo.org

Report ID: 89083

Coordination Meeting Notes:

HAM7: VAC team look at viewports, and then pump down today.
Ion Pump swaps continue this week
HAM1: This will go into next week (they have a meeting on this work later this morning
Cable pulling in lvea (OPS/SEI be mindful of HEPI status)---> ISI damped HEPI offline
Ops EVE shifts CANCELED this week and will revisit Feb17 Week Ops EVE shift status.

H1 SEI - H1 ISI CPS Noise Spectra Check - Weekly (FAMIS #39337)

corey.gray@ligo.org — Mon, 09 Feb 2026 08:12:54 -0800

Author: corey.gray@ligo.org

Report ID: 89082

FAMIS Link: 39337

Only CPS channels which look higher at high frequencies (see attached) would be the following:

ETMx_ST1 H1
ETMx_ST1 H2
ETMy_ST1 H2
ETMy_ST2 H1

In the bash window we get this note:

"HAM high freq noise is elevated for these sensor(s)!!!: HAM1_CPSINF_V2 & V3 "

SEI

H1 CDS - mains minor power glitch 06:49:45

david.barker@ligo.org — Mon, 09 Feb 2026 07:49:39 -0800

Author: david.barker@ligo.org

Report ID: 89081

The GC UPS reported a brief switch to battery power this morning due to a minor glitch in power on all three phases. The MSR UPS did not report.

Images attached to this report

LHO General - Mon Day Ops Transition

corey.gray@ligo.org — Mon, 09 Feb 2026 07:41:06 -0800

Author: corey.gray@ligo.org

Report ID: 89079

TITLE: 02/09 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: 6mph Gusts, 4mph 3min avg
Primary useism: 0.03 μm/s
Secondary useism: 0.34 μm/s
QUICK SUMMARY:

HAM7 not pumped down. HAM1 JAC work continues. LVEA is in the Bifurcated Laser SAFE state. And Seahawks are Super Bowl Champs!

LHO VE - HAM3 Annulus Ion Pump Replacement

gerardo.moreno@ligo.org — Sun, 08 Feb 2026 18:40:19 -0800

Author: gerardo.moreno@ligo.org

Report ID: 89078

(Jordan V., Gerardo M.)

-Late entry

On Friday we removed and replaced the ion pump for HAM3. We replaced the copper gasket twice, the first gasket seal had a bad leak, it was hard to see the mating surfaces due to visibility issues (laser safety goggles and not enough light).
After installing a second gasket, we started pumping down the annulus system and pressure went down fast. Last pressure reading at the aux-cart was 4.63x10^-05 Torr.
BTW, we have other 4 (four) ion pumps to replace.

Images attached to this report

LHO VE - Sun CP1 Fill

david.barker@ligo.org — Sun, 08 Feb 2026 11:37:13 -0800

Author: david.barker@ligo.org

Report ID: 89077

Sun Feb 08 10:11:56 2026 INFO: Fill completed in 11min 52secs

Images attached to this report

H1 IOO - Multiple beams mostly in PIT coming out of EOM (pictures)

keita.kawabe@ligo.org — Sat, 07 Feb 2026 15:55:27 -0800

Author: keita.kawabe@ligo.org

Report ID: 89076

Multiple beams mostly in PIT coming out of EOM (pictures and history)

1W into HAM1, otherwise it's hard to photograph these clearly.

The first picture is right after the YAW adjustment was made but before adjusting PIT. The card is held just ABOVE the main beam, you can see four blobs that look like some kind of ghost beams. (If you try to picture the main beam, it's so bright these ghosts become hard to capture.)

The second picture is after the first PIT adjustment. You can only see maybe two blobs, but later we found that the rest went below the main beam (sorry no "below" picture).

So, to recap the history of the beam quality,

Feb/03-04 (alog 89041).
- The beam had horisontal line that was clearly visible even at 100mW input (horizontalstreak.jpg).
- JAC beam was found to be higher than 1mm relative to the EOM, the latter was raised, the horizontal line was gone but I noted "but there was still a vertical streak that was hard to photograph".
- Then the EOM was adjusted in YAW, I still noted "not sure if it's great though, it's hard to photograph but something faint might be coming out of the EOM". But note that the power was 100mW.
Feb/05 (alog 89059)
- With 1W input, Jason and Masayuki clearly saw multiple ghost beams in PIT above the main beam.
Feb/06 (this alog)
- EOM was adjusted in YAW, seemingly no change i.e.there were still multiple ghost beams in PIT.
- Adjusting the EOM PIT angle made ghost beams go up and down relative to the main beam, but they didn't seem to go away.

Other things.

Just to make sure, we turned down the 9MHz and 45MHz RF power to 3dBm and disconnected the 118MHz and 24MHz cables and nothing changed.

We know that the crystal wedge is supposed to be horizontal and we know that the wedge orientation is correct. When we first installed the EOM in chamber, the EOM transmission was deflected horizontally in +Y direction.

INS, ISC, SYS

Images attached to this report

H1 IOO - Horizontal beam position offset on the EOM input and output aperture (on the side plates)

keita.kawabe@ligo.org — Sat, 07 Feb 2026 15:25:34 -0800

Author: keita.kawabe@ligo.org

Report ID: 89075

Horizontal beam position offset on the EOM input and output aperture on the side plates.

We realized that the nominal beam position on the EOM input and output aperture is NOT centered on the crystal cross section projected onto the side plate face, the beam is horizontally offset in +Y direction.

Look at the first cartoon (cartoon.jpg) and references therein. The beam spot offsets are 0.91mm on the input side plate and 0.54mm on the output side plate, respectively, assuming that the beam deflection angle per surface of EOM is 2.35 degrees as implied in D2500130.

0.91mm is not a small offset, it's almost 1/4 of the crystal thickness (it's 4x4x40mm).

This means that the beam should be (see nominal_sideplate.png, note that the drawing scale of the input aperture in this is twice that of the output aperture):

~3.9mm from the left (+Y) edge of the visual alignment aid notch on the input side plate,

~3.2mm from the right (again +Y) edge of the aperture hole on the output side plate.

Measurements, adjustments and measurements made the beam closer to the nominal location.

Based on the above knowledge, we took pictures of the beam position on the input/output aperture, paying attention to the errors that could arise from the parallax (which is unavoidable), i.e. the sensor card should be as close to the face of the side plate as possible and the beam spot on the sensor card should be as close to the sentor of the camera sensor as possible. This was a tougher job than you think.

Anyway, in the first round of measurements, we convinced ourselves that the beam was:

off in -Y direction by 0.7mm relative to the nominal beam position on the input plate of the EOM,

off in +Y direction by 0.5mm on the output,

give or take 0.2mm or so (the error is based on two pictures for the input beam position with random variation in parallax coming from camera position and the distance between the side plate surface and the viewer card).

We rotated the entire EOM base by using two dog clamps against the EOM base and inserting appropriate shims (EOM_rotation.png). We didn't use the YAW adjustment feature for the EOM pivot plate because there's no way to rotate it in a controlled manner.

After the first adjustment we thought that the beam coming out of the EOM looked better (which might have been false). On the second adjustment the beam looked the same or slightly worse (which might have been false) and we reverted back to the same position as the first adjustment.

According to the pictures (input_measured.jpg and output_measured.jpg), the beam position is

0.2mm off in -Y direction on the input,

0.6mm off in -Y direction on the output,

again give or take 0.2mm or so. Apparently the input got much better, we overshot for the output but it's not worse.

This is the last measurement done based on the pictures. After this, we reset the dog clamps without shims and used them as the YAW reference.

ISC, SYS

Images attached to this report

LHO VE - Sat CP1 Fill

david.barker@ligo.org — Sat, 07 Feb 2026 10:34:15 -0800

Author: david.barker@ligo.org

Report ID: 89074

Sat Feb 07 10:09:46 2026 INFO: Fill completed in 9min 42secs

Images attached to this report

aLIGO LHO Logbook

H1 IOO - Comment to RTP test, ghosts from the new batch spare crystal, no ghost from the old batch spare (Elenna, Betsy, Keita)

H1 General - OPS Wednesday Day shift summary

H1 IOO - RTP test, ghosts from the new batch spare crystal, no ghost from the old batch spare (Elenna, Betsy, Keita)

H1 IOO - Comment to RTP test beam path in the OSB optics lab (Elenna, Betsy, Jenne, Keita)

H1 SEI - SPI Fiber Collimator: Refined Collimation / Lens Position / Beam Waist Diameter Measurement Setup

LHO General - Mid Station chilled water trending

LHO VE - Wed CP1 Fill

H1 CDS - All models on h1sush7 stopped. Restarted models and reset HAM7 SWWD.

H1 General - OPS Wednesday Day shift start

LHO VE - HAM7 Pumpdown Update

H1 IOO - RTP test beam path in the OSB optics lab (Elenna, Betsy, Jenne, Keita)

H1 IOO - Comment to IMC beam alignment, power to HAM6 looks OK

H1 CDS - Cables staged in LVEA

LHO VE - Comment to HAM7 Viewport Inspection

X1 SUS - Four HRTS moved to the VPW for storage

H1 CDS - Comment to CDS Maintenance Summary: Tuesday 10th February 2026

H1 CDS - CDS Maintenance Summary: Tuesday 10th February 2026

LHO VE - HAM7 Viewport Inspection

H1 IOO - IMC beam alignment, power to HAM6 looks OK

H1 CAL - Comment to PCAL EX Endstation measurement

LHO General - Tues DAY Ops Summary

H1 ISC - Comment to IMC cavity axis now vs pre-vent

H1 SEI - Setting Lens Position for SPI In-vac SuK Fiber Collimator Beam Profile: No Systematic Error; Waist Position is just *extremely* Sensitive to Lens position

H1 CAL - PCAL EX Endstation measurement

LHO VE - Tue CP1 Fill

H1 ISC - PSL +/-12V Kepco Supply Replacement (Dome Camera Supply)

H1 ISC - Turned off HV for HAM7

LHO VE - HAM7 Pumpdown

LHO General - Tues DAY Ops Transition

H1 IOO - Comment to Checking EOM crystal

H1 IOO - Comment to Checking EOM crystal

H1 CDS - h1sush7 timing glitch, models restarted

H1 SQZ - SUSSQZIN and SUSFC1 SDFs before restart

LHO General - Mon Day Ops Summary

H1 ISC - Comment to EX Ion Pump X-8 Scanned

H1 ISC - EX Ion Pump X-8 Scanned

H1 IOO - Checking EOM crystal

H1 SQZ - Comment to Recabling OPO in HAM7

X1 SUS - BBSS Put in Can

H1 PSL - PSL 10-Day Trends

LHO VE - Mon CP1 Fill

H1 IOO - Comment to Vertical splited beam investigation

LHO General - Comment to Mon Day Ops Transition

H1 SEI - H1 ISI CPS Noise Spectra Check - Weekly (FAMIS #39337)

H1 CDS - mains minor power glitch 06:49:45

LHO General - Mon Day Ops Transition

LHO VE - HAM3 Annulus Ion Pump Replacement

LHO VE - Sun CP1 Fill

H1 IOO - Multiple beams mostly in PIT coming out of EOM (pictures)

H1 IOO - Horizontal beam position offset on the EOM input and output aperture (on the side plates)

LHO VE - Sat CP1 Fill

H1 SEI - Setting Lens Position for SPI In-vac SuK Fiber Collimator Beam Profile: No Systematic Error; Waist Position is just extremely Sensitive to Lens position