Miranda, Dave:

Friday afternoon we updated the cable labeling for the ACC BNC coax cables at EX, MX and MY. EY cables were already complete.

At EX we reconnected the BNC for H1:PEM-EX_ACC_OPLEV_ETMX_Y_DQ which we had found to be disconnected. Plot shows it had a signal until the 23rd June of this year.

Miranda, Dave:

Over the past week we have documented the LHO PEM accelerometers and produced an as-built  wiring drawing

This was in response to a possible misreading of accelerometer(s) with the wrong channel names.

We found three accelerometers with incorrect names, which date back to pre-O4, so I'm tagging DETCHAR.

We fixed this at 16:00 Thursday 13th August 2026 PDT by remapping the BNC connections on the front panel of APC1. The cable going to port12 was moved to port13, that going to port13 was moved to port14 and that going to port14 was moved to port12.

We tap-tested the EBAY_FLOOR accelerometer at 16:10 and this showed up on H1:PEM-CS_ACC_EBAY_FLOOR_Z_DQ

I reconnected the vacuum lines used to pull air through the dust monitors that are stationed in the PSL laser room and ante room. Back in September 2025 (alog87005) they were disconnected because the old pump had been running in reverse after a power glitch and the carbon graphite vanes blew air through the lines as well as little bits of the vanes. Since then we have replaced all of these pumps with ones that cannot contaminate the areas they are trying to sample. The corner station is running on a scroll pump with a automated back flow valve and the end stations are on diaphragm pumps. 

Dust counts in the PSL laser room and ante room should now be considered real.

Pending Filter Files:

h1calcs had a modified filter file waiting to the loaded. The running filter file was last loaded 16jul2026, H1CALCS.txt was modified at 10:52 27jul2026 and not loaded. I made a local copy of the modified file, then removed the changes by doing a subversion revert. This cleared the CFC flag on h1calcs.

SDF Diffs:

Several models have outstanding SDF diffs (screen shots attached below)

Links to all of the B&K'ing that has happened this year to wrap up the vent. List is in reverse cronilogical order.

Rahul K, TJ S

Numerous beam dumps and other coated panels were added to HAM3 to mitigate stray light in the area. While we couldn't spend the time to test all of them, we chose the few that seemed like they would be the worst offenders.  The best map I know of for the newly added parts is in D2600134. Accelerometer locations marked on the last attachment of this log.

Accelerometer location 1 -  -X+Y corner of optical table. Acc dofs = IFO dofs

Meas 1 - On the table baffle mount in -X
Meas 2 - -Y 
Meas 3 - -Z

Location 2 - On the table next to the scraper baffle addition. Dofs = IFO

Meas 4 - Hitting the mount of the scraper baffle addition. +Y direction
Meas 5 - +X hit on same mount
Meas 6 - -Z on same mount

Since we couldn't mount the accelerometer directly to any of these new beam dumps and panels, we had to mount it to the table and pick up all of the other table noises. That said, I don't see anything terrible in these, so it looks okay to move on.

[Nathan Holland, Jenne Driggers]

TL;DR

DC to 30 mHz BLRMS have been working as of 2022 - see LIGO-T2200025. These can be added to the BLRMS monitoring screen, and hopefully will be useful. They may need appropriate calibration. See attachment 1 for an example.

More Information

Historically the DC to 30mHz BLRMS did not work - they would diverge to +/- infinity after some time. This was corrected as of 2022, see LIGO-T2200025, by changing the C code in the RTCDS. This RTCDS change was approved in ECR LIGO-E2200027 and has been active for some time. One example of the relevant channels is H1:PEM-CS_SEIS_LVEA_VERTEX_X_BLRMS_0MHZ30, e.g. for the DC to 30 mHz seismic BLRMS at the LVEA along the x direction. Attachment 1 shows a 5 minute trace of the second trends for this channel.

Possibly this has been discussed in the past at the Friday SEI meetings, and no use yet, has been found for this BLRMS band. It may be interesting to properly calibrate these channels, place them on the monitoring screens, and then see if they are of use.

Just noticed DM 10 has been steadly going up for last 6 hours. So has the wind - could be an unpropped door? Just adding it here for log. Screenshot attached.

TITLE: 05/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Work continued today in HAM2 and currently there is still work going on at the test stand on the BBSS.

The LVEA is currently LASER SAFE

LOG:

Mitchell and I placed the new central beard baffle with a cutout for SPI on HAM2. It went on without issue after Mitch reminded me how to adjust the panels.

I then attached the accelerometer to the L bracket and tried hammering in various places. There wasn't much real estate, so I'm not sure how this will turn out. Data still needs to be analyzed, and I'll post pictures of hit locations then as well.

J. Kissel, J. Warner
ECR: E2400026
WPs: 13237, LHO:13238
Final Design Doc: T2400145
Relevant Systems Level Drawings:
    . Mechanical Assemblies
        :: ISIJ Reflector D2400102
        :: HAM Table Baffles D1700335
        :: HAM2 Systems Layout D0901083 (not yet-inclusive-of-SPI)
    . Electronics Wiring Diagram 
    . Cable Routing In-vac Cable Routing Plan from G2401479 (pages )
    . Flange Layout D1002873-v11

Executive summary:
    - Removed ISIJ +X-side, center, HAM2 ISI table baffle from D1700265-v4 Type 2 
        :: Bracket mounting bolts left screwed into ISI optical table for this will eventually become a D1700265-v4 Type 3 and remounted.
    - Installed ISIJ Reflector + QPD Assembly D2400102 on +X ISI side wall (D071057-v2), with its shroud (D2500030) in place
        :: We didn't weigh it, but the SW Assembly predicts a mass of 1.96 [kg], which we can likely round up to 2.0 [kg] with the shroud installed.
    - Routed and connected QPD read-out cable system to D3 flange, F10 spigot.
    - Routed and connected picomotor cable system to existing D1101515 quadrupus leg Cable #3, J4 
        :: Cable #4, J5 is connected to IO PM5 mirror, Cables #2 J3 and #1 J2 were reset in neat coil with connectors floating to avoid electrical grounding as before.
    - Nudged make-shift baffle system using D1700261 ballast mass baffle mounted vertically on the +X / +Y / Beam Height corner of the chamber wall upon entry into beamtube.
        :: the will DEFINITELY need a technically-minded reset.

In at 10:30a PT and out by 12:30a PT. It's so lovely when everything goes to plan!

Pictures and further info to follow in the comments below.

FAMIS 39862 Vibration Sensors To Gauge Health Of HVAC Fans Site Wide
 

Closes FAMIS37263

No new issues (LAB2 and LVEA5 are not connected currently), or unreasonable/concerning counts at any location.

Samantha Callos, Genevieve Connolly, Robert Schofield, Ryan Short, Carlos Campos

The detchar presentation summarizing the injection analysis can be found on the DCC at: https://dcc.ligo.org/LIGO-G2600768

A PDF of this report has also been attached to this alog along with a spreadsheet of the injections.

An earthquake tripped the SWWDs for ETMY, ITMX and ETMY at 18:30 PDT yesterday evening. I untripped these 07:40 this morning.

TITLE: 04/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

Iluminators for HAM3 BSC1 and 2 are now on.
HEPI and ISI for BSC2 is locked out. tagging PEM. and there is now a Red H1:SYS-ETHERCAT_DEVICE_1_SLAVECOUNTACTUAL due to the iluminator Chassis device that Fil turned on between BSC1 and BSC1 in the beergarden to allow the illuminators to turn on. tagging CDS. 

PCAL troubleshooting: 
Dripta and I were trying to take FFT's of PCAL Lines for more Power budget work and we noticed that the PCAL Y laser is off with no current on H1:CAL-PCALY_LASERDIODECURRENT. I trended the channel back and compared it with some channels that I thought may link it to the IOP restarts. 
Dripta went to EY to toggle the Laser power rocker switch just in case it was just a simple issue of a turn it off and back on again.  Tagging CDS again.

I noticed that MC1 & 3 were saturating. 
IMC H1:IMC-WFS_GAIN was set to 0 and the history was cleared to solve the problem of MC1 & MC3 were being saturated.
Trending some channels that were suspected to perhaps  be the cause of the junk signal and thus the cause of the saturations.
The IMC ASC has it's own block to do power normalization, different from the LSC power normalization. The output of this block is "INNORM" used to normalize MC2 NSUM for the IMC WFS triggering.
Relavent FRS ticket: 
https://services1.ligo-la.caltech.edu/FRS/show_bug.cgi?id=9387

More IOP model restarts happening again for HAMS 7,8 then HAM 5,6, & BSCs 1,2, & 3.
Please see the attached SDF Diffs for HAMs 5, 6 and the BS: 
SUSSR3
SUSRM
SUSIFOOUT
SUSSQZOUT
SUSBS (my bad I had sort on substring selected with an old Optical Align string in the search field.)
All SDFs were accepted before the IOP restart. 
ITMS  IOPs have not been rebooted yet. Tagging SUS, SQZ & ISC

MC2_trans Beam Dump twas Twissled today, then put back into original place. 

The ITMs had their IOP's restarted after a time cable swap today as well.
All SUS were turned back to Aligned.
SEI for HAM 2,3,4  and BSC 1 & 2 still have their HEPI's and or their ISI's WD tripped or other wise in a ISI Damped Hepi offline state.

As you can see from this ITMY trend, Jim went inside to lock the ISI and tripped the ISI, then Jason went in and tripped it again, then there was an IOP restart. 

A slightly less exciting trend of ITMX.


LOG:
 

(Jordan V, Corey G)

In prep for upcoming BBSS Install, "broke" bolts (which is slang for loosened them) on:

• BSC1's +Y Door in the Beer Garden
• BSC2's Dome (to see if giving the Dome's O-Ring some time to "decompress" helps us out at all with removal next week).  

BSC1's +Y Door Bolts (mostly) Removed & Accelerometer Cable Disconnected

BSC1's door had all bolts but (4) removed.  Sadly, I removed the bottom (easy ones) bolts first and then when I got to the top bolts they were very hard to loosen because of some sag.  Additionally, their access is horrible with:  a stiffening plate for the chamber right above the rear access to these bolts, then there are cable trays also in the way, and the C3 fabric cover is draped in your face the whole time.  Jordan helped out and we were able to get the last top bolt removed.  We also loosened the (4) bolts 1-turn which is the typical procedure.

There was an accelerometer still cabled up to this door.  I disconnected the cable (labeled "PEM:BSC1_ACC_X") and stuffed the cable into the cable tray above this door.

Time lapse of me removing half the bolts in this LINK (since we only files allowed in alog have to be smaller than 15Mb.)  :(

BSC2's Dome Bolts (mostly) Removed, But Have A Galled Bolt!

BSC2's dome bolts were removed.  4-bolts were left in place (they were loosened and then tightened up a little).  One notable, is there is 1-galled dome bolt.  Jordan and I used the long wrenches to see if we could use more force to help it break loose, but no luck.  We did not try pouring some alcohol on the bolt to help as a lubricant.  The bolt is loose and has about 1-2mm of a gap on it.  So, the pros could try use even longer cheater bars, a saw cutter, or they were also chatting about a tool to cut the nut off.  At any rate,