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Reports until 10:18, Friday 30 January 2026
LHO VE
david.barker@LIGO.ORG - posted 10:18, Friday 30 January 2026 (88969)
Fri CP1 Fill

Fri Jan 30 10:07:58 2026 INFO: Fill completed in 7min 54secs

 

Images attached to this report
H1 General
anthony.sanchez@LIGO.ORG - posted 08:00, Friday 30 January 2026 (88967)
Friday Ops

TITLE: 01/30 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: 0.04 μm/s
    Secondary useism: 0.40 μm/s 
QUICK SUMMARY:
LVEA is LASER HAZARD with HAM1 & HAM7 still open for in chamber work.

Potential HAM7 work: 
 Tweak Alignment from cable Rubbing, OBO & TF

Potential HAM1 work: 
Align Path out
IOT2L Beam profile measurement at 100 mW
Replace JM1/JM3 fixed mirrors with HTTS
Lock MC with HAM1 in air
Bifricate LVEA HAM1/South Bay/Work at Height all Laser Haz, rest of LVEA Laser Safe



 

 

H1 SQZ
sheila.dwyer@LIGO.ORG - posted 21:39, Thursday 29 January 2026 (88966)
HAM7 work today

This morning Rahul took a transfer function of the OPO suspension and found that adding a zip tie to the new connector didn't help the transfer function, which is still similar to 88921.  We decided with Jeff to live with this as it is, and we spent the rest of the day working on resolving the clipping through the VIP introduced by alignment shifts that happened as we were addressing the cables.  

We moved A:M3 enough that we no longer see evidence of clipping in the SFI1 both passes, we measure 0.96mW out of the OPO and about the same power in transmission from SFI1 on the the return from the filter cavity.  We then saw that the beam was clipping in SFI2, and adjusted B:M1 until we were measuring about 0.88- 0.9mW after SFI2, but we had clipping on the aperture attached to B:L2.  We had nearly lost the beam to SQZT7 by this time, so we spent some time restoring that by adjusting pitch on B:M3 and yaw on B:M4 (with the platform unlocked it is difficult to adjust pitch on the tough pitch knob for B:M4).  This brought us to a point where we can see 0.7 counts on the OPO IR PD on SQZT7.  

At the end of the day, we were still seeing loss at B:L2, where the beam was only about 0.82mW.  We also need to restore the alignment onto the irises on SQZT7.  

We will need to readjust the alignment onto the filter cavity QPDs before we close the chamber. 

 

H1 ISC (EPO, INS, ISC)
keita.kawabe@LIGO.ORG - posted 16:55, Thursday 29 January 2026 - last comment - 07:58, Friday 30 January 2026(88963)
JAC EOM Thursday (Jennie, Elenna, Jason, Masayuki, Betsy, Keita)
  1. EOM was put in chamber and moved to its final location. One temporary iris, a cable bracket for the picomotors and one dog clamp for the last lens for JAC needed to be relocated as they interfered with the EOM pivot base.
  2. In-vac cables were identified and were connected to the EOM. Minor annoyance about the cable strain relief.
  3. EOM S11 coefficients were measured and were acceptable though the dip frequencies were not the same as in the lab, so we haven't retuned it.
  4. EOM was connected to the RF sources (now we're modulating!).
  5. The light goes into and comes out of the EOM.
  6. We forgot that the EOM wedge has a big effect to deflect the beam. We started working on the alignment downstream of the EOM and this will continue tomorrow.

Details to follow.

Comments related to this report
keita.kawabe@LIGO.ORG - 21:04, Thursday 29 January 2026 (88964)

EOM tuning results

It's worth noting that we haven't done any tuning after EOM was transported from the lab to HAM1. Frequencies changed a bit but nothing to worry about.

Below is a table of the dip frequencies and S11 coefficients when the EOM was placed in its final location. They aren't bad, 9 and 45 are as good as anybody can do.

(We also measured them when EOM was placed at the edge of the table, there were measurable differences but nothing disastrous.) 

nominal / measured center frequency [MHz] measured S11 coeff [dB]
at nominal / center frequency
9.100230 / 9.1015282 -21.96 / -22.29
24.078360 / 24.074976 -25.84 / -26.74
45.501139 / 45.499614 -23.19 / -23.15
118.30299 / 118.294670 -25.29 / -26.0

Connection

FieldFox network analyzer was connected to the modulation patch panel at the bottom of PSL rack (which is kind of hard to find, see the first picture). Back of that panel is connected to the in-air cable that runs all the way to the vacuum feedthrough on HAM1.

By connecting 50 Ohm terminator to each in-vac cable, we confirmed from FieldFox that ISC_RF5-B1, B2, B3 and B4 correspond to 9, 45, 118 and 24MHz as specified in D1900511-v12 page 43 and 24.

Before connecting the cables to the EOM, we performed S11 calibration by connecting a short plug, 50 Ohm plug and nothing to the SMA connector of in-vac cables via class B SMA elbow.

After the EOM was relocated to its final location, RF sources were connected to the front of the patch panel.

RF levels of the signals directly coming from the 118MHz and 24MHz RF patch panel were: 10.76dBm for 118MHz, 14.2dBm for 24MHz according to FieldFox. 

45MHz and 9MHz come from the EOM driver and I didn't bother to measure the power.

Other things

In three_persons_untangling.jpg, Jennie, Jason and Elena (left to right) are untangling JAC EOM cables together.

Images attached to this comment
elenna.capote@LIGO.ORG - 17:07, Thursday 29 January 2026 (88965)

About the cable strain relief posts:

The four SMA cables were connected to the SMA elbow connectors on the EOM. The strain relief posts appear to be designed such that each cable is sandwiched between the two viton pieces, with one screw above and one screw below. I was a bit confused about how exactly to use the screws with hex nuts attached. I instead used the third bottom screw to loosen to slide the cable in, and then tighten. It was helpful to have someone else pinch the viton at the top while I tightened the screw. This is how it looks.

The two cables on the right hand side of the EOM mount feed straight through the strain relief into the SMA connection, this is fine. However, the placement of the post on the left hand side is a bit short of where the SMA connections are, so the cable bends a bit to make it through the strain relief post and go to the connector. This is tricky because the SMA cable is also very stiff. I don't know if this is a problem. I took several pictures of how this looks just in case. You can see how one side is straight and the other side is "S" shaped through here.

There are two more angled shots of the EOM in its place on the table.

About EOM placement:

Jason and I lifted and placed the EOM carefully together while Jennie held the cables. We roughly dog-clamped the cables to the table for now. Jason fine-tuned the EOM alignment by lining up the mechanical mount to holes on the table.

Overall, not bad for placement. We opened the light pipe after placement, locked the JAC and saw the beam go in to the EOM and then come out of the EOM on the other side!

To confirm, we used the thorlabs power meter to check. We measured about 82-84 mW before the EOM, and then 79-80 mW coming out of the EOM.

Further alignment work:

We proceeded to try to realign the beam from JM2 to JM3, given the significant deflection of the beam due to the EOM crystal. There are two irises between the mirrors to guide the alignment. Jason found it very tricky to align the beam to both. During the process, JM2 was knocked over and now has some scratching and cracks near the edge of the mirror. It is fine to use it for alignment now, but the mirror will need to be replaced. The team is working on finding a spare now.

Images attached to this comment
corey.gray@LIGO.ORG - 07:58, Friday 30 January 2026 (88968)EPO

EPO Tagged.

H1 General
oli.patane@LIGO.ORG - posted 16:32, Thursday 29 January 2026 (88962)
Ops Day Shift End

TITLE: 01/30 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: EOM is in!! Still some work to be done for HAM1 and HAM7. LVEA IS LASER HAZARD
LOG:                                                                                                                                                                                                                                                                    

Start Time System Name Location Lazer_Haz Task Time End
15:44   Corey LVEA YES Running HAM1 cable brackets out 15:52
16:18 FAC Kim, Nellie LVEA YES Tech clean (Nellie out 16:30) 17:48
16:22 FAC Randy LVEA YES Measuring on BSC2 platform 16:52
16:29 FAC Nelllie EY, MY n Tech clean 17:39
17:28 JAC Keita OptLab/LVEA n EOM work 19:35
17:31 SQZ Rahul, Sheila LVEA YES HAM7 alignment 19:59
17:34 FAC Randy LVEA YES BSC2 platform work 19:37
17:38 VAC Jordan MY n Looking for parts 17:56
17:51 JAC Betsy, RyanS LVEA YES Moving IOT1 away from chamber (RyanS out 19:35) 19:43
17:57 SPI Jim OptLab n SPI work 19:11
18:01 EE Fil, Marc LVEA YES Pulling cables 19:14
18:03 JAC Elenna OptLab/LVEA n EOM work 19:35
18:04 FAC Kim LVEA YES Tech clean 18:24
18:10 JAC Masayuki LVEA YES EOM 19:35
20:30 FAC Randy LVEA YES BSC2 platform work 22:49
20:43 EE Fil LVEA YES Cabling for BHD 21:56
20:43 JAC Keita LVEA YES EOM installation work 20:58
20:49 JAC/VAC Jason, Jennie, Jordan, Keita LVEA YES Replacing septum cover (Jordan out 21:13) ongoing
21:02 EE Marc LVEA YES Helping with JAC 21:21
21:10 JAC Elenna LVEA YES JAC ongoing
21:26 SQZ Sheila, Rahul LVEA YES HAM7 aligning 00:01
22:25 EE Marc, Yuri LVEA YES Looking around 23:25
22:39 BHD Betsy, Jenne OptLab n BHD things 23:54
23:19 JAC Masayuki LVEA YES JAC work ongoing
23:27   Richard LVEA YES Checking in on everything and being nice to people 22:57
00:21 FIT Matt YARM n Running ongoing
LHO VE
david.barker@LIGO.ORG - posted 10:21, Thursday 29 January 2026 (88959)
Thu CP1 Fill

Thu Jan 29 10:07:23 2026 INFO: Fill completed in 7min 20secs

 

Images attached to this report
LHO FMCS (PEM)
oli.patane@LIGO.ORG - posted 09:12, Thursday 29 January 2026 (88958)
HVAC Fan Vibrometers Check FAMIS

Closes FAMIS#39852, last checked 88845

Corner Station Fans (attachment1)
- MR FAN1_170 has been relatively loud since it was turned on on Tuesday.
- All other fans are looking normal and within range.

Outbuilding Fans (attachment2)
- MY FAN1_270_1 is quite noisy, but since it's at the midstation I think that's okay
- All other fans are looking normal and are within range.

Images attached to this report
H1 SUS (SUS)
rahul.kumar@LIGO.ORG - posted 09:07, Thursday 29 January 2026 (88957)
HAM7 OPO cable dressing (round 2) - Yaw shows no further improvement

Sheila, Jeff, Rahul

Yesterday afternoon we moved around two more cables on the OPO (see picture attached for reference). For the first cable (marked by circle) we lifted the cable connector from the OPO and attached it to the nearby pillar using a PEEK tie. For the second cable (marked by arrows in my picture) I provided more relief to it.

This morning I took transfer function measurements for Y dof (0.02Hz bw and 5 averages, with Yaw dof. un-damped and other dof. being damped during the measurement) - see screenshot attached below. I don't see any improvement (in frequencies splitting) - red trace is the latest measurement and blue is the previous one taken by Jeff two days ago.

Images attached to this report
H1 SQZ
sheila.dwyer@LIGO.ORG - posted 08:49, Thursday 29 January 2026 (88956)
OPO suspension cabling and clipping in HAM7

Yesterday Rahul and I went to HAM7 and adjusted A:M3 in the negative pitch direction to relive the saturation of ZM1 noted in 88939.  This was partially sucsesful, after the shift the beam was no longer clipping on the SQZT7 periscope without offsets on ZM1, but it was a little low in pitch on the first iris and the power on the OPO IR trans PD was 0.4 rather than 0.6 counts.  With the power meter we can see that there is still clipping between the input to SFI1 and the return beam from the filter cavity out of SFI1. 

Rahul adjusted the cables a bit, adding more slack to the one for the OPO temperature controler (before photo shows this as the lighter colored  cable with the S routing on the nearby pillar).  The beam was still  After that the PSL FSS would not lock, preventing us from dither locking the OPO.  

Rahul moved the connector for the new translation stage from the lid of the OPO and zip tied it to the pillar on the rear blade spring.  

Oli and Jeff are looking at suspension transfer functions right now.  I was able to improve the power on the PD from the control room by pitching ZM1 + 400 urad and yawing +500 urad, but there is still not as much light as we expect on SQZT7 IR PD, so we will have to continue this in laser hazard today. 

H1 General
oli.patane@LIGO.ORG - posted 07:34, Thursday 29 January 2026 (88953)
Ops Day Shift Start

TITLE: 01/29 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: 4mph Gusts, 3mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.58 μm/s 
QUICK SUMMARY:

HAM1 and HAM7 work continuing today

H1 AOS
keita.kawabe@LIGO.ORG - posted 21:24, Wednesday 28 January 2026 - last comment - 11:55, Thursday 29 January 2026(88952)
Wed. Jan/28: JAC EOM is ready to be transported to the chamber (Elenna, Keita)

We've assembled the whole EOM assembly including the pivot base/plate assy and the strain relief post and confirmed that the EOM face/side/bottom plates are isolated from the pivot base/plate.

We've tuned the EOM such that S11 parameter at the modulation frequencies are all within 1dB of the bottom of the dip.

We still saw that the frequency shifted for 118 and 45MHz when we tapped the EOM body around, even though there was no appreciable change in 24 and 9MHz. Each jump was small, like 5kHz or 10kHz or nothing sometimes, but they jumped. Surprisingly, at least for 118MHz peak, after the frequency jumped in one direction due to my tapping on the side plate (e.g. the input side), I tapped the other side plate (e.g. the output side plate) and the frequency jumped back into the opposite direction. This was very consistent.

This means that my expectation was wrong. An expectation that somehow something (like coil wires) is caught by something else (like the core by the friction), and that tapping things will release these "something"s into lower potential state and that eventually they all settle.

Realizing this, we stopped tapping, we just tuned as good as we could and stopped.

Tools and parts were wrapped and bagged. EOM assy was wrapped in a foil. These things will be transported to HAM1 tomorrow. 

In the first two attachment, Elenna is tuning the trickiest frequency (118MHz). 

Following pictures show the fully assembled unit from the back (+Y), input (-X), output (+X) and front (-Y). In front.jpg, note that I'm only using one washer for the low profile 10-32 socket head cap screw. I used to use two, but the screw still stuck out just enough to make things tedious and inconvenient when lowering the pivot plate over the pivot base. Though the screw is 0.5" long and not the initially specified 10-32 x 0.375", with one washer it seems to work. 

Next, look at one 1/4-20 screw below the above mentioned 10-32 in caution.jpg. When tightening/loosening that screw, don't use a T-handle wrench unless it's a ball end tool, because you WILL damage the SMA connector thread. Even if you use an L-shaped tool, if you don't pay attention you can damage it. Be careful.

Last picture showcases a happy mood in the optics lab after the successful day.

Images attached to this report
Comments related to this report
keita.kawabe@LIGO.ORG - 08:36, Thursday 29 January 2026 (88954)

We modernized the measurement apparatus and used FieldFox (Agilent/Keysight's handheld network analyzer) instead of 4396B. This was really convenient and helpful because one person could hold the analyzer at a convenient position/angle for the other who was turning the trim cap.

Also it has a splitter and a directional coupler built in so there's no need to connect any such external devices, it's just the analyzer, a cable and the EOM. (But of course you still have to calibrate with short/open/load like in 4396B, see alog 88887.

corey.gray@LIGO.ORG - 08:37, Thursday 29 January 2026 (88955)EPO

EPO tagged.

elenna.capote@LIGO.ORG - 11:55, Thursday 29 January 2026 (88961)

Just want to add some notes:

  • once the EOM was mounted on the base plate, we used a multimeter to check the isolation of the EOM assembly and the base plate. There was no continuity between the sides, face plate, and bottom of the EOM and the base plate
  • the strain relief posts required different amounts and types of washers to ensure that when the posts were screwed down they faced the correct direction according to the drawing. You can see this in the third image in Keita's original alog. The left side strain relief post uses one 0.025" washer and eight 0.002" washers. The right side post uses one of the given slotted washers and one thick washer, I can't remember the size (but not one of the already-mentioned washers). Figuring out which washer combination was correct was a very annoying process.
  • For tuning: this is a very tricky process because the trim pots are very sensitive. To make this extra hard, it's important to note that just bringing the yellow tool in to connect to the washer changes the capacitance significantly, and removing the tool and your hand changes it back. This means that you have to over/undershoot the tuning while your tool is in, and then check to see if you have it right by removing the tool. This requires a lot of trial and error to determine exactly how much overshoot is required. I'll admit that I got it mostly through guessing and luck. I don't see how it would be possible to do this tuning without being right next to the EOM, so in-chamber adjustments are going to be incredibly difficult.
H1 SQZ (EPO)
anthony.sanchez@LIGO.ORG - posted 16:55, Wednesday 28 January 2026 (88878)
Removed a few parts from HAM7

Friday Jan 23rd Sheila, Karmeng, & myself removed 3 Irises, and swapped out a PD for a beam dump.
First Karmeng & I Turnt up the purge air & took pictures of the table.  
Then we found all the irises Sheila wanted to remove:
Iris 1.... which was one of the 3 Sheila wanted to remove along with Iris 2 and Iris3 near by.

We decided to swap a Photodiode for a Beam Dump due to the scattered light documented in this here FRS ticket, as putting a beam dump infront of the PD was not possible due to Space constraints.
Swapping this PD out required some expert level HAM7 Yoga so Shelia did the switcheroo.

I'm sure it will be fine, but the PD was in place to catch light that is there when the IFO is locked.... and well since the IFO wasn't locked... we Eyeballed the placement of that beam dump that took it's place.  So we are fairly sure the Beam Dump is in the right place.  Oh! I took a few before pics of the PD too just to do some comparing with the after pics of the Beam Dump.
We did check all the beam paths in HAM 7, but that last beam dump we can't check so ¯\_(ツ)_/¯ Looked good to us.

Thanks to Jordan for the last minute purge air cram session.

Later!





 

Images attached to this report
H1 PSL (OpsInfo)
jennifer.wright@LIGO.ORG - posted 13:04, Wednesday 28 January 2026 - last comment - 11:57, Thursday 29 January 2026(88948)
Input power to HAM1 at 1W

Jennie W, Jason O

 

Jason and I added four beam dumps - two before we turned the power up, two after.

There were no beams leaving the table at 100mW but we dumped two beams going towards the PSL septum plate (one was transmission through JM1).

Jason saw one leaving the table after we were at one watt so this and the transmission throuhg JM3 + JM2 are now dumped.

 

Comments related to this report
jason.oberling@LIGO.ORG - 17:13, Wednesday 28 January 2026 (88951)

PSL power into HAM1 has been returned to ~100mW and the PSL rotation stage is de-energized and locked out once again.

jennifer.wright@LIGO.ORG - 11:57, Thursday 29 January 2026 (88960)

Pictures of the beam dump positions are attached.

BD one: BD for beam reflected towards PSL from JAC (-x direction).

BD two: beam transmitted through temporary JM3, BD (right one in photo) at edge of table nest to JM1 tip-tilt (in its temporary position in bottom right of photo).

BD three: BD in bottom of picture added for beam transmitted through temporary JM1.

Photo of both BD 1 and 3 zoomed out.

BD four: BD on -x side of table (towards HAM2) catching beam transmitted through JM2, shown in mid-left of photo.

Images attached to this comment
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