h1suslo12 model now temporarily running as the BBSS model alongside the original (but slightly modified) BSFM h1susbs model

WP13213 Jeff, Tom, Oli, Dave:

h1susbs (the original BSFM model) was changed slightly to no longer drive the 2nd LIGO-DAC chans 08-11. This frees these up for use by the BBSS model. At the same time 4 IPC senders and 11 IPC receivers were removed.

Instead of replacing h1suslo12 with a brand new h1susbbss model, with all the associated RGC/DAQ/puppet changes, we chose to keep the h1suslo12 model essentially in name only, but change its function to drive the BBSS and test QOSEMS.

To do this, Oli changed the h1susbbss.mdl file to:

 - use h1suslo12's dcuid=188

 - remove all IPC senders

 - reduce the number of DAC channels, only using those freed up by the h1susbs changes

This approach means the H1.ipc and testpoint.par files are unchanged. The H1SUSLO12.txt filterfile and safe.snap files are substantially changed, but these had not been commissioned. The H1SUSLO12.ini file was also essentially rewritten for BBSS with the exception of some FEC channels.

There were no issues with rebuilding and installing the new h1susbs and h1suslo12 models. The old versions were stopped before the new ones were started because we are swapping DAC drives between these models.

DAQ Restart

The DAQ was restarted for the model changes. There were no issues found.

CDS Overview

The h1suslo12 entry on the CDS Overview has a new color/label to denote its current usage as the BBSS model. Also note the removal of some IPC senders from h1susbs means we have continuous IPC receive errors on the h1susmc2 and h1seiproc models.

HAM3 D3 feedthru swapped

The D3 feedthru on HAM3 was swapped from the 3-port version with 3x Dual DB25 feedthrus to the single piece 12x DB25 connector feedthru.  We re-attached the in-vac cables that were originally in that port and Betsy re-attached the in-air cables so that the SUSes can be controlled overnight. 

Cables were unplugged on both the vac and air sides, so keeping track was a bit tedious.  I have started an AS-BUILT cheatsheet which tracks the serial numbers as we go on the main LHO HAM3 Flange Layout DCC page https://dcc.ligo.org/D1002874-v10, see the google doc.  Attached is a snapshot of the sheet with the D3 work logged so far.  
TBC...

Note, for the 24hours that this feedthru work and recabling was happening, I turned off the chassis that powers this ISC/IO_245 cable to POPA/POPB at the transimpedence amp  SLot U25 of the ISC_R4 rack near the PSL (Thanks Kissel for the consult to get me there).  Per Fil, the picomotors had already been "turned off" when their plug in was disconnected at the ISCT2 picomotor "box", so I didn't do anything for that one. 

OMC QPD sense pin problem: Solved

Summary:

The problem of "Sense" pin of OMCA QPD1 short-circuited to the BHDS structure (alog 90029 from yesterday) was tracked down to the free "sense" wire inside the QPD enclosure touching the aluminum part inside the enclosure. We solved the problem by trimming the wire short.

Merely opening the QPD enclosure broke the short circuit temporarily:

We lifted the OMCA QPD1 from the BHDS while QPD2 is still attached to the BHDS and confirmed that the sense pin for the QPD1 is conductive to the QPD1 enclosure but not to the BHDS. As soon as we opened the back of the QPD1 enclosure, the short-circuit to the enclosure was broken. 

It seemed that the free part of the sense wire was a bit too long and bowed in the enclosure, allowing the tip of that wire to touch the inside wall of the enclosure itself (see Elenna's first image in her comments).

Cutting the sense wire short broke the short circuit permanently:

I cut the wire short such that it cannot touch the enclosure (Elenna's second picture), reassembled the enclosure and confirmed that there's no short circuit between the sense pin and anything else. 

Repeating the tests:

We put the QPD1 back on the BHDS and connected the cable to the transimpedance amplifier. On the oscilloscope, it was immediately apparent that the terrible 60Hz noise (which was 6.5V p-p) was gone (Elenna's 3rd picture).

We repeated the flashlight test, all segments responded with O(1)mV negative voltage (i.e. positive output minus negative output from the TIA amplifier was negative few mV maximum) while the dark offset was O(0.1mV).

We also measured the dark noise. It seems that all measurements for both QPD1 and QPD2 were limited by the noise of the TIA. Low frequency noise especially 60Hz and its harmonics varied from channel to channel, but in all cases it seemed that there's very little difference between the noise measured with QPD connected VS the noise without QPD. As such, I'll just show here a few examples. First attachment is the QPD1 segment 1 noise with the QPD attached, the second is the same thing but without QPD connected to the front panel of the TIA. They look identical. The third one is the QPD1 segment 4 (with QPD attached, not much different without QPD). The fourth one is the QPD2 segment 3 (with QPD attached, not much different without QPD).

There's no reason to suspect that QPD1 for OMCA is broken (nor QPD2).

Removed, Tested, and Reinstalled the two 8 Channel Satellite Amps in SUS-R2

We pulled, tested, and reinstalled the two 8 channel satellite amplifiers in SUS-R2.

S1106058, S1200173.

1 of 4 HEPI Corner station pumps have been off since Dec 14 2025 power outage, remaining 3 pumpstations were running at ~95% to cover since

Last week I tripped the HEPI pump controller valving out the BSC2 actuators, it took me until today to try to recover it. In the process of investigating this I found that one of the 4 corner station HEPI pump carts has been more or less off since a power outage in December. The remaining pump stations have been running at about 95% drive to cover for the lost cart. I am working on some revisions to the famis and asking to Tony to add a verbal notification if there is a mismatch in the manifold pressures for the 4 corner pump stations.

Nice to know that we have overhead to lose one pump station and still supply the corner HEPI with pressure. Drive is much lower now that all 4 are running again.

Attached image shows how long we have been running with only 3 pumps. Crosshair in the upper left plot shows approximate time of the power outage. Bottom right shows we have been running at ~1900 cts drive out of 2048 total available since then. We are back around 1100 cts drive now.

HAM3 chamber vent work - SLiC, BAFFLE ASSY attached to both PR2 and MC2

Mitchell, Rahul

This morning we entered HAM3 chamber and attached the baffles (for stray light control) to both PR2 (HSTS) and MC2 (HSTS) suspensions. The baffle assembly design is shown D1700257_V5. These baffles were attached (directly mounted on the HSTS structure) on both the sides of the optic, i.e  HR and AR side.

Before attaching the baffles I inspected both the optics and they looked nice and clean, hence didn't needed any First Contact cleaning. 

I am attaching pictures below for reference.

We found that both PR2 and MC2 had two missing 1/4-20 threads on the HR side for attaching the mounting rail (D1700249_v1) of the baffle (Mitchell will attach a picture showing the same). Typically, these rail need four holes on the structure for securing them. However, we used the lower two threaded holes for attaching these mounting rail and they were rigidly secured. On the DCC I found that both PR2 and MC2 have D020023_V3 of the HSTS_Structural Weldment Assembly, latest D020023_V7 has more holes on the frame.

We also noted that one of the Siskiyou mount is very close to the MC2 baffle (AR side) as shown in the picture here. However, I can confirm that they are not touching and there is a decent amount of clearance between them. 

I still need to perform health checks on both the suspensions to rule out any rubbing and will post the results as a comment over here.

Note - counts on dust monitor were in single digit before and after entering/exiting the chamber (Thanks to Ryan C for arranging this). 

Generating an SHA Key and posting it to git.ligo.org so you can clone repos on a new laptop

J. Kissel, J. Freed

It's not the "right" place to find this information, but I was helping Josh get started with git, and I found my 2022 LHO:63463. We needed that step of generating an SSH key and posting it to his git.ligo.org profile. Of course, in 4 years, a minor detail has changed -- the location of where you put it on the web.

So, here's the 2026 version of the instructions on how to generate an SSH (SHA256) key and get ligo.org to recognize it enough to give you permissions to clone a project:

##ALL THE SAME
     jeffrey.kissel@opslogin0:/ligo/gitcommon/Calibration/ifo$ ssh-keygen 
     Generating public/private rsa key pair.
     Enter file in which to save the key (/ligo/home/jeffrey.kissel/.ssh/id_rsa): 
     /ligo/home/jeffrey.kissel/.ssh/id_rsa already exists.
     Overwrite (y/n)? y
     Enter passphrase (empty for no passphrase): 
     Enter same passphrase again: 
     Your identification has been saved in /ligo/home/jeffrey.kissel/.ssh/id_rsa.
     Your public key has been saved in /ligo/home/jeffrey.kissel/.ssh/id_rsa.pub.
     The key fingerprint is:
     SHA256:XQnWdPoBVmHwdsX3i+qpeTvANGQHFiI7zTXFN1oF7ew jeffrey.kissel@opslogin0
     The key's randomart image is:
     +---[RSA 2048]----+
     |     . . *B+=+O+.|
     |      = ++.=.@ .+|
     |     o oo . B B +|
     |      .  + o o =.|
     |        S o   + .|
     |         o   . E |
     |          . .    |
     |          .+.    |
     |         o++o    |
     +----[SHA256]-----+
     jeffrey.kissel@opslogin0:/ligo/gitcommon/Calibration/ifo$ cat /ligo/home/jeffrey.kissel/.ssh/id_rsa.pub 
     ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCebNagyBGRjYsoP4RT8KZ74HLONo6B4VOwBNUQpOPrNnMvQTD3NfTQJHWTgkcAFiCB2yLeioqJQmrigTd9BjnKx/1Eo4z1wvhC/hvCvD07IcvLgogP1lujyDyx7qYHBw46W1pFXXt1wqkFYFiDxcsNRgqhFqFBvdyVJdfPZs+GHqK8Df6AfKKZTWqrYgzpqYbvzl9q21E3vEUyTQamoftBimCZVSj1cz7+5W7giWBcBNmcuHzrV2/Af7pfzj8zoveXv/9qISyLKp0F4zlB52/lih9TzxTg36l8MCzIb2592xVsRaYtuxb8SA4Sst8bUqVvUFclj/rCD1ytEDfMvKyp jeffrey.kissel@opslogin0

###HERE'S WHERE IT'S DIFFERENT

Then I 
- went to https://git.ligo.org/-/user_settings/ssh_keys/ (####INSTEAD OF https://git.ligo.org/-/profile/keys)
- copied the above public id_rsa.pub hash into the "Key" field, 
- then let it auto-title the key,
- change the with expiration date something in the year 2080, and 
- hit the blue "add key" button.


Now, you can, say go to the https://git.ligo.org/spi/simulation/ page, and hit the blue "Code" button (####it's no longer called "Clone"), hit the two squares icon for copy in the "Clone with SSH" address, then in a (new or refreshed) terminal type

    $ git clone git@git.ligo.org:spi/simulation.git

and you're in business. 
From there, the CONTRIBUTING guide to pydarm is a place that I found the most helpful in how to develop / interact with a git project.

Tue CP1 Fill

Tue Apr 28 10:09:03 2026 INFO: Fill completed in 9min 0secs

 

Ops Tuesday Morning report

TITLE: 04/28 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 9mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.12 μm/s 
QUICK SUMMARY:

When I arrived there was an alarm for the Fire Pumps sounding on the verbals machine. Fire Pump 1 was on at 14:28 today possibly because of Work permit 13207.

LVEA temp is climbing and hasn't returned yet. Perhaps this is just the mega cleanroom affecting the temperature, but I will keep an "I" on it.

 

 

Workstations updated

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

OMCA-QPD1 sense pin is shorted to the suspension platform, causing massive 60Hz problem (Elenna, Keita)

Problem

We started checking the health of QPDs and were puzzled that all four quadrants of the OMCA QPDA are much, much noisier than OMCA QPDB.

Note, there's a naming inconsistency about the QPD numbering between D2200276 wiring diagram and D0981811 (see "cartoon version"). 

D0981811	OMCA QPD-1	OMCA QPD-2	OMCB QPD-1	OMCB QPD-2
D2200276	QPD-2	QPD-1	QPD-8	QPD-7

Cause of the problem

Anyway, the problem was tracked down to short-circuit of common mode noise sensing line for OMCA-QPD1 (pin 11 of DB25 inside the vacuum, pin 3 outside of the vacuum, see attached) to the metal part of the suspension structure (i.e. ISI surface and the chamber) which in turn is grounded to the lab ground.

OMCA QPD-2 as well as both of the QPDs for OMCB are fine.

All QPD segments (incl. OMCA QPD1) responded to the flashlight.

Dark noise test: OMCB QPDs looks OK, not sure about OMCA QPDs

We connected a dual-QPD trans impedance chassis (S1102832, which is the original version of D1002481) to the OMCB QPDs like this:

QPDs-DB25 assy - in-vac cable (DB25F-DB25F)  - feedthrough simulator - DB25F-to-DB25M-cable - S1102832 front panel.

We looked at the output of the TIA with SR785 when there's only ambient light on QPDs (not much), segment by segment. No segment was extra noisy or anything.

OMCA QPDs are a different story because of the 60Hz problem. 

We'll see if the problem could be solved by somehow reassembling the QPD or cutting the noise line. 

ISCT1 and JAC Table Enclosures

Cabling to the ISCT1 and JAC table enclosures complete. Use caution when moving the cleanroom, one of the legs is close to the patch panel/cables on ISCT1.

Ops Day Shift Summary

TITLE: 04/27 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: The BSC2 cartridge has been flown over to the test stand in the West bay.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
15:16	FAC	Randy	LVEA	-	Prep for cartridge removal	15:44
15:28	FAC	Kim	LVEA	-	Technical cleaning	16:38
15:30	AOS	Tony	LVEA	-	Connecting headset	16:13
16:51	FAC	Kim	LVEA	-	Technical cleaning	17:58
16:58	IAS	Jason	LVEA	-	Grabbing laptop	17:06
17:07	AOS	Tony	LVEA	-	BSC2 cartridge removal	20:36
17:07	SEI	Jim	LVEA	-	BSC2 cartridge removal	20:36
17:11	FAC	Tyler	LVEA	-	BSC2 cartridge removal	20:33
17:13	VAC	Jordan	LVEA	-	BSC2 cartridge removal	20:36
17:14	FAC	Mitchell	LVEA	-	BSC2 cartridge removal	20:36
17:17	TCS	Camilla	Opt Lab	-	Looking for a lens	17:32
17:24	AOS	Betsy	LVEA	-	BSC2 cartridge removal	20:36
17:24	VAC	Gerardo	LVEA	-	BSC2 cartridge removal	20:36
17:26	VAC	Travis	LVEA	-	BSC2 cartridge removal	20:01
17:32	TCS	Camilla, Madi, Adrien	EX	YES	ALS/HWS table work	18:39
17:34	EE	Fil	LVEA	-	Cabling HAM1 tables	19:07
17:38	AOS	TJ	LVEA	-	BSC2 cartridge removal	20:32
17:43	FAC	Chris	LVEA	-	FAMIS checks	18:29
17:57	SUS	Tom	Vac Prep	-	Cable making prep	18:32
18:03	SUS	Rahul	FCES	-	Looking for a table	18:29
20:11	ISC	Keita, Elenna	Opt Lab	-	BHD OMC work	21:43
20:18	SUS	Oli, Tom	Vac Prep	-	QOSEM cables	Ongoing
20:43	EE	Fil	LVEA	-	Cabling HAM1 tables	22:18
21:08	PEM	Ryan C	LVEA	-	Setting up dust monitor at test stand	21:39
21:09	FAC	Randy	LVEA	-	Tidying up	21:18
21:46	TCS	Camilla, Madi	EX	YES	ALS/HWS table work	Ongoing
22:05	ISC	Elenna, Adrien	Opt Lab	-	Tour	22:46
22:58	IAS	Jason	LVEA	-	Prepping FARO for tomorrow	23:06
23:04	SEI	Jim	LVEA	-	Checking dial indicators on BSC2	23:27
23:06	ISC	Keita	Opt Lab	-	BHD OMc work	Ongoing
23:17	PEM	Ryan C	LVEA	-	Swapping dust monitor fuse	Ongoing

PSL 10-Day Trends

FAMIS 31135

The PSL was offline for a bit last Tuesday for chassis work that took down the interlock (alog89965), but came back up with only a few things being different. Most notably, the PMC is at a slightly different temperature, so the transmitted power is a bit lower while the reflected power is a bit higher.

BSC2 Cartridge on the Test Stand

The BSC2 cartridge was removed from the BSC2 chamber today and placed on the Test Stand in the West Bay (+Y bay).  The lift took 3 "test lifts" to make very minor adjustments to the CG prior to lift out of the chamber - on the 4th lift, we were very well balanced so embarked on the flight.
Like LLO, the BS had it's "Stay Leg" assemblies and Vibration Absorber Assemblies removed for the flight.  This means it was probably lighter than the 2013 time (alog 5689) when we did this which had the weight slightly heavier.  The cartridge plus 3-point lift fixture and load cell together all weighed 9380 lbs.  It was rotated 90deg Counterclockwise per the procedures and landed on the threaded rod in the test stand with little issue other than careful craning and spotting.
All went as expected and according to the procedures E1200433-v3, E1200971-v4 and associated docs.

Mitchell, Travis, Tyler, Randy (on crane) all up on the platform
Jim and Tony inside of BSC2
Gerardo, Jordan on the eMod as Support
TJ on the camera
Betsy soaking it all in (support)

A pre-lift meeting was held to go over the teams and maneuver details (again) at 9am prior to work starting.

Particle counts up at the dome level were all 0,0 before starting.
More photos and videos will be posted when those folks have them available.

Covers used - A BS/QUAD SUS tube cover up underneath, an ISI cover up on the ISI, the BSC Cartridge sock which encased the whole thing, dropped down to Jim and Tony once the lift was up a couple feet.  

The bulk of the work was from ~10:30am-1pm.  Most of the time before was getting folks in headsets and gear and getting equipment on.