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Reports until 07:35, Thursday 18 June 2026
LHO General
thomas.shaffer@LIGO.ORG - posted 07:35, Thursday 18 June 2026 (90664)
Ops Day Shift Start

TITLE: 06/18 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 9mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.14 μm/s 
QUICK SUMMARY: The LVEA is still in laser hazard, but the light pipe is currently closed. SPI, BBS, SQZ chamber work continues today.

H1 CDS
david.barker@LIGO.ORG - posted 07:07, Thursday 18 June 2026 (90663)
Extended edc_green_ioc to include missing PWREX

While Patrick is upgrading the EX Beckhoff power monitor IOC I have added these channels to the temporary edc_green_ioc.py to "green up" the EDC by supplying the missing 82 channels. IOC was restarted at 07:03

LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 01:26, Thursday 18 June 2026 - last comment - 18:41, Thursday 18 June 2026(90662)
CP1 Cooldown Started

(Jordan, Travis, Jake, Owen, Gerardo)

After taking some RGA scans of CP1, and pushing nitrogen gas through the cryotrap (we injected nitrogen gas at the top sensor line for about 10 minutes), then we started the cooldown, or did we?  First, we opened the "bypass" valve (fully open) to measure the number of turns to guesstimate a less than 10% open valve, per procedure E960127. Then we opened the bottom draw valve to release LN2 out of the dewar.  We opened both valves around 2:00 pm, bottom draw fully open and bypass valve only 10%, but by 7:40 pm local time we terminated the cooldown, we didn't want to risk for something to go array overnight. 

We did not see a sign that the cryotrap was getting nitrogen, nothing on the exhaust (the exhaust pressure remained the same), nothing on the cryotrap level (remained at zero), pressure internal to the cryotrap remain level, and the consumption remained level at the dewar for CP1.  We are going to look more into this Thursday.

 

Comments related to this report
gerardo.moreno@LIGO.ORG - 18:41, Thursday 18 June 2026 (90677)VE

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

CP1 cooldown re-start, apparently one or both of the valves did not respond as they should have, either the "bottom draw" and the "bypass" valves did not open yesterday, or one of them did not open, do not know which.

This morning I opened the valves in a different manner, and paid close attention to their behavior, the "bottom draw" valve made a small pop as I opened it, so I closed the valve and then opened it again, I had to do that about 3 different times, the last time there was no pop, it seems as if the valve was letting go of the sealing component, on the third attempt I was able to hear the LN2 rush thru.  Same for the "bypass" valve, opened it with care and paid attention to the sounds it made, no pops noted, but to make sure I opened and closed the valve 3 times, never opening it more than 1/2 turn.  Then set it the same way as yesterday, the guestimate of 10% open, about 0.8 turns.  Then I was able to hear the nitrogen gas out of the exhaust line.  Left CP1 and went to check on the progress via MEDM screens and plots.  Soon we had the first numbers on the pump level % full, we started with a very tiny number but little by little the cryotrap started to fill.  Because of the experience of with the above mentioned valves I decided to actuate early the LLCV, but only opening it up to 2%, eventually with time and two cell phones I was able to note that the LLCV was indeed actuating good.  Soon the 85% came along and it was time to hand over the controls to the PID, which it did not have any issues, well 1 issue, the 15% output low limit was to high, the PID railed, so I lowered it to 10%, this number will be assessed on the upcoming days to see if we leave it or not.  We left the RGA scanning during and post the cryotrap cooldown.

Vacuum pressure in CP1 has dropped and currently we are at 3.8x10-09 Torr, from about 4.0x10-08 Torr this morning.

The consumption of LN2 was good, the dewar dropped about 2.24% to fill the cryotrap.

The turbo pump continues to pump on the system and it will until we reach at least 1.0x10-09 Torr or better.

Images attached to this comment
H1 SPI
jennifer.wright@LIGO.ORG - posted 17:52, Wednesday 17 June 2026 (90660)
SPI QPD B and A calibration

Jennie W, Josh F, Jeff K

Today we centred the beam on both QPDA and QPDB (see Josh's alog # 90659). In the process we calibrated the picomotors we use to steer onto QPD A in HAM3 and QPDB in HAM2.

We calibrated the beam steering to M_C1 (QPDA) using the picomotor M_M1 on the ISIK breadboard in HAM3.

The beam moves across the mirror (~2 inches) which corresponds to 3000 steps on the picomotor.

For future reference to move in -y global coordinates direction on QPD you move the M_M1 pciomotor down. This moves it in positive yaw or left on the photodiode, as we did small steps of 100 across the surface in yaw letting the QPD readout settle in between each step.

In the other degree of freedom, the beam moves across the mirror 2 inches with 2000 counts right on the picomotor. This move is in +z in global coordinates, and therefore down in pitch on the QPD.

I took another short calibration series of steps to calibrate the QPD with the picomotor and moving up or right with the picomotor moves up in pitch on QPD A.


Then we moved to HAM3 and did the same calibration for pitch and yaw on M_B4 and QPDB.

The calibration in M_B4 is 1500 counts of picomotor drive for the 1 inch optic. When driving up on picomotor, you drive in -z direction on M_B4, which should be up in pitch on QPD

We got another calibration in the x direction, with 1700 counts of picomotor to go across the optic, when driving picomotor right you move in +x on M_B4. which should be down in yaw on QPD.

Images attached to this report
H1 SPI
joshua.freed@LIGO.ORG - posted 17:31, Wednesday 17 June 2026 (90659)
SPI, ISIK Install Day 5

J. Freed, J. Kissel, J, Wright,

Continuing from 90645(Notes are stored here). Today we calibrated the picos on M_M1 and M_C1, got the beams centered on both QPDs, saw our first beat notes in the Meas IFO.

In order we did:

Images attached to this report
LHO General
thomas.shaffer@LIGO.ORG - posted 16:33, Wednesday 17 June 2026 (90657)
Ops Day Shift End

TITLE: 06/17 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
SHIFT SUMMARY: SPI workmain beam in vac checks, and HAM7 work keeping the LVEA in laser hazard today. CP1 cool down began. Other various activities throughout the day.
LOG:                                                                                                                                                                                                                                                

Start Time System Name Location Lazer_Haz Task Time End
20:18 SAF LVEA IS LASER HAZARD LVEA YES LVEA IS LASER HAZARD 12:18
14:36 FAC Kim LVEA Y Tech clean 17:44
15:29 TCS Camilla LVEA n Take picture 15:34
15:51 SAF Tony LVEA N->Y Transition the LVEA to laser HAZARD 16:12
16:13 VAC Jordan LVEA y Checking on HAM2 annulus 16:30
16:16 SPI Jeff, Josh, Jennie LVEA YES HAM3/2 SPI work 20:06
16:31 VAC Gerardo LVEA Y Check on systems post power glitch 16:37
16:39 CC Ryan C LVEA Y Bringing dust mon charger out 16:44
16:58 CRS Jim, Shoshana LVEA - H2 Y CRS work 18:12
17:19 HWS Camilla, Madi Opt Lab n Looking for lenses, Camilla then going to HAM7 18:07
17:19 SQZ Camilla, Ryan S LVEA - HAM7 Y SQZ work 19:43
17:20 - Randy LVEA Y Talking with Jim 17:30
18:13 VAC Jordan LVEA Y CP1 RGA scan 18:40
19:26 VAC Gerardo LVEA Y Deliver N2 bottle 19:34
20:08 IFO Betsy, Keita, Ibrahim LVEA Y Checking on main beam in vac 22:35
20:09 VAC Jordan, Jake, Owen LVEA Y CP1 cool down prep (Jordan out @2105) 21:17
20:33 EE Fil EX & EY N Checking High Voltage to the ESDs at both End Stations. 22:33
20:37 VAC Gerardo LVEA Y Joining CP1 cooldown team 21:17
20:55 cds Tony CER n pluggin in a cds laptop charger to the cds laptop vault. 21:04
20:57 VAC Travis LVEA y Checking on CP1 21:30
21:12 SUS Oli CER n Looking at cables 21:24
21:24 HWS Camilla, Madi LVEA Y TCS cabinet lens hunt 21:43
21:25 CDS Patrick EX n Reimage Beckhoff computer 23:25
21:26 SEI Jim, Shoshana EY n BRSY troubleshooting 22:35
21:38 SQZ RyanS LVEA YES Working on HAM7 ongoing
21:40 SQZ Camilla LVEA - HAM7 Y HAM7 work ongoing
22:48 CDS JennieW CER N Returning a laptop to the CDS laptop Vault to charge. 23:08
22:49 - Tom, Cory LVEA Y Touring, filming ongoing
H1 SUS (SUS)
ibrahim.abouelfettouh@LIGO.ORG - posted 16:32, Wednesday 17 June 2026 - last comment - 17:21, Wednesday 17 June 2026(90656)
BBSS Gross Alignment Efforts

Ibrahim, Betsy, Keita

The BBSS Oplevs aren't to be trusted (alog 90648). 

Today, we went into BSC2 to attempt to use ITMX and ITMY as a lever using the PSL beam. We put in 500mW flashes with the rotation stage locked out.

We found the beam nicely (multiple modes) on both ITMs, albeit a bit yawed. We moved PR3 from -233 to -583 in Yaw, which recovered the beam on the center of both ITMX and ITMY.

For context, we had already centered the BBSS to the structure on the test stand but found that we were not on the oplev once we went back into the cartridge.

We're now working on seeing if we can trust this BBSS alignment, or if we have to make mechanical or offset changes.

Comments related to this report
keita.kawabe@LIGO.ORG - 17:21, Wednesday 17 June 2026 (90661)

At the end of the day, PSL waveplate rotator was set to 200mW and then denergized and locked, and the light pipe was closed.

I made the following changes for the whitening and didn't change them back. I will, later.

  Used to be Temporarily changed for now
ASC-AS_C 18dB, 2 whitening stages 18dB, 3 whitening stages
ASC-OMC_A and B 0dB, 2 whitening stages 27dB, 3 whitening stages
ASC-POP_A and B 12dB, no whitening 9dB, 2 whitening stages

ASC-AS_A_DC and B gain were high and I didn't change them.

LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 08:09, Wednesday 17 June 2026 (90649)
HAM2 Doors Installation

(Randy, Jordan, Jake, Owen, Travis, Gerardo)

Both doors were installed on HAM2, no issues to report.  The usual dance, take one door off, to then move the cleanroom to be able to remove the other door, thank you all for the help moving this cleanroom.  

There are some pecularities that we like to note about the doors, we noted some rust on both flanges of HAM2 -Y and +Y, and some embeded particulate on some of the O-rings, metal type all over, the particles were removed with a clean wipe, however there was a "green" fiber on the +Y door O-ring, outer O-ring, around 11 O'clock, this fiber runs with the seal and not across, so we did not poke at it.

Then we connected an aux cart to the annulus system, and started the pump down, we will add second aux cart to help with pump down.

Next, we like to inspect the viewports on this chamber, but this job is going to require laser safe and no table near the door.  We did note something on the central high quality viewport and we like to take a closer look at it.

Images attached to this report
H1 SUS
betsy.weaver@LIGO.ORG - posted 07:43, Wednesday 17 June 2026 (90648)
BBSS Oplev back alive

On Tues Oli tracked down and made the final move step to get the BBSS (still now named the BS in controls) Oplev signal live.  I uncovered the Oplev and released any errant stops.  SInce the sum was 2k instead of it's nominal 20k, Oli tried driving the BBSS sliders around, no luck, so we went out and looked for the beam in the Oplev box with Jason.  The Oplev Beam is offset in Pitch by a beam diameter at at the diode and roughly centered in yaw.  We are chewing on this.  Since we did not restore the plane of the BBBS to the exact same spot as the BS was we should not have expected the beam to be on the Oplev even if it's pit/yaw is correct, due to translation of the beam.  That said, I would have expected more of a yeaw error, less pitch.  Today we are going to take a peek at the in-air PSL MC flashes to see if we can see anything heading to the output arm which gives us confidence in our IAS pointing alignment on the test stand (and can therefore ignore the oplev).

LHO General
thomas.shaffer@LIGO.ORG - posted 07:27, Wednesday 17 June 2026 (90647)
Ops Day Shift Start

TITLE: 06/17 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 7mph Gusts, 5mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.12 μm/s 
QUICK SUMMARY: The LVEA is in the laser safe bifurcated state at the moment. SPI, SQZ, BBS, FARO work continues.

H1 SPI
joshua.freed@LIGO.ORG - posted 17:07, Tuesday 16 June 2026 (90645)
SPI, ISIK Install Day 4

J. Freed, J. Kissel, J, Wright, F. Clara

Continuing from 90621 (Notes are stored here). Today we brought the SPI picomoters into play, got caught up on our backlog of alogs, and began probably our toughest opical alignment during install. The periscope...

In order we did:

H1 SPI
joshua.freed@LIGO.ORG - posted 16:57, Tuesday 16 June 2026 (90644)
SPI, Pathfinder Install, First hints of efficiency drift in IFO REF

J. Freed,

At 9:18:50 this morning our aligned REF IFO started to fluctuate in efficency. (SPI_REFIFO_Efficency_Oscilation_Start.png) This happened before while building SPI in the optics lab; however, then it was happening contiuously, while now our REF IFO was fine until it started happening. 

SPI_REFIFO_Efficency_Oscilation_Start_C.png At the exact same time as when this started, the REF PWR MON fliped to negative power for a split second. (The second time we have discovered negative power). I have no clue to what caused this flip
 
SPI_REFIFO_Efficency_Oscilation_Start_NC.png I checked other possible causes: (set frequency changes and pico moter movements) but they were minutes before this occured so unlikly to be the cause.
Images attached to this report
H1 SQZ
camilla.compton@LIGO.ORG - posted 16:53, Tuesday 16 June 2026 (90629)
HAM7 Vent - Tuesday June 16th - realigned to FC and swapped FC WFS A, co-alignment found bad
Ryan S, Madi, Camilla
 
Realign to FC
Yesterday we unlocked the OPO SUS 90623 but released this slightly shifted the alignment coming off the OPO SUS towards the FC. Today, we moved A:M3 to center on the ZM3 iris and ZM3 for the retro-reflection. Sliders attached. ZM3 went from P -150, Y -660 to  P -130, Y -620.  We mainly moved in YAW (A:M3 only in YAW) and double checked that the height at ZM3 and FC1 was around 6.25" still. After this, beam was centered on ZM4 iris, we did not touch B:M4. 
Once we did this, the beam was getting to the SQZT7 PD with minimal clipping dips, there were still some dips from max level but we compared this to nighttime June 2nd (with chamber open and OPO SUS unlocked) and it is the same.
 
Power through OPO SUS Check 
Similar to in 90573, where we measured between 2% and 5.5% power drop. Today, total of around 1.38 to 1.44mW out of OPO, before A:DC1. Measured drop of between 0.02 and 0.08mW though to off OPO after B:M4. This is between 2% and 5.8% power drop. We expect at least 3% (1% for each SFI and 1% at B:BS1) and our power budget  has 4.7% measured.
 
Green Misalignment 
Before we started we noticed that the green beam towards FC is grossly misaligned in Pitch, attached photos at ZM1 iris (green beam low) and ZM3 iris (green beam high). We are not sure when this happened, as the SK path was very off yesterday, it could have happened before the OPO was unlocked. We will check everything is secure and then attempt to use a single pico-motor to fix this as the is the most likely thing to have got bumped. 
 
Swapping FC WFS A 
When we started the beam was misaligned in pitch on the FC WFS, very low on the lens. We moved the picos in Pitch to get the beam on both A and B. The picos both still have plenty of range. We then verified which QPD was A, marked its location with a dog, and at the chassis turned off the +/- 18V for WFS before unplugging both WFS cables. We then unplugged the WFS A and removed it, removed the diode detector holder D2000384 from the enclosure D2000246 (marked part #4) and swapped it to the new diode housing (add ICS link) and reinstalled.
Ryan caught we needed to put H1:SQZ-RLF_QPD_A_SEG_C_OFFSET back to nominal (I'd changed it in March), then everything then seemed as expected. We need to better center onto these QPDs tomorrow. 
Images attached to this report
H1 SPI
joshua.freed@LIGO.ORG - posted 16:45, Tuesday 16 June 2026 - last comment - 09:05, Wednesday 17 June 2026(90642)
SPI, Pathfinder Install, Issues with Saturating Oscillating FBR_PWRIN_REF.

J. Freed,

WE HAVE DISCOVERED NEGATIVE POWER

The FBR_PWRIN_REF PD that monitors the Power coming from the REF beam of the interferometer has gains alot of noise during certain intervals. Sometimes the noise even goes negative power. The noise is corelated with the frequency difference between the ref beam and the meas beam we set. The lower the frequency difference the higher the noise

SPI_PW_REF_Noise_Pt3.png Shows the correlation between Set fequency and the noise
 
SPI_PW_REF_Noise_Pt1.png is a close up of the transition. Since we have a 1sec ramp time the noise starts one second after setting a new frequency difference.
 
SPI_PW_REF_Noise_Pt2.png Shows that the noise is sawtooth at a frequency double the set frequncy. 
 
I currently have no evidence of what this could be.
Images attached to this report
Comments related to this report
jeffrey.kissel@LIGO.ORG - 09:05, Wednesday 17 June 2026 (90651)
Here's a screenshot of the oscillations stopping at 09:08:08 PDT (16:08:08 UTC).
There's something in the MEAS signal as well, but the amplitude is less (at least with this 32 kHz sampling rate).

Of course, nothing changed in the signal readout chains at this time. But lots of things are happening surrounding it.

Also, the oscillations are different frequency in the MEAS vs. REF path (again, with the "this is clearly aliasing" grain of salt).

But, since we're not saturating when the oscillations are NOT present, I don't think it's an issue with the transimpedance *resistor*; it's probably just that we need to double the capacitance, dropping the pole frequency from 13.5 kHz to 6.7 kHz.

We'll put an analog o-scope on the signal this morning to confirm.
Images attached to this comment
H1 SEI (SEI)
shoshana.apple@LIGO.ORG - posted 10:26, Friday 12 June 2026 - last comment - 09:55, Tuesday 23 June 2026(90607)
ETMY BRS not damping down

The ETMY BRS seems to be continuously ringing up. I've tried to make the changes to the thresholds which was the previous fix outlined in 87634 for the same BRS, and will check back in on it later to see if just increasing the thresholds helped at all.

 

Changed thresholds:

H1:ISI-GND_BRS_ETMY_LOWTHRESHOLD 800-->2000

H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD 2000-->4000 Changed

Additonally I changed the ETMX BRS drift control to 6.00V and the ETMY BRS to 2.00V to try and better center them

Images attached to this report
Comments related to this report
shoshana.apple@LIGO.ORG - 15:55, Wednesday 17 June 2026 (90654)

[Shoshana, Jim]

Shut off the damping for ~2 hours hoping it would damp down somewhat but the ringing just got worse

Jim recaptured the ETMY BRS frame to see if that would solve the problem, but it did not.

We went down to the BRS to test if the dampers were wired correctly/making contact. We checked the voltage going through and applied a voltage directly to the dampers to make sure the wires in vacuum were connected to the plates. We found that the 2 pin (+ direction) and 5 pin (- direction) (diagram below) were the pins which applied voltage to the dampers, were applying voltage as expected (maxing out at around 2.9V). It looks like applying a voltage directly made the BRS move as expected (we applied 3V to each pin one at a time in order to ring it up or damp it down), so we don't think there is an issue with the connection, and voltage was making it through the cable. 

After watching the signal and the voltage going through the cable for a while, my best guess is that the + damping doesn't turn off fast enough when the BRS switches directions which causes it to continuously oscillate, but switches off eventually so it doesn't continue ringing up?

Michael Ross (who wrote the Beckhoff code) will be here next week, so we will ask him to take a look at it.

Images attached to this comment
shoshana.apple@LIGO.ORG - 09:55, Tuesday 23 June 2026 (90706)

Michael is in this week and fixed the EMTY BRS by raising the upper threshold (H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD) from 4000-->8000 for 20 minutes, see 90693

Current Thresholds:

H1:ISI-GND_BRS_ETMY_HIGHTHRESHOLD: 4000

H1:ISI-GND_BRS_ETMY_LOWTHRESHOLD: 2000

 

Looking through ndscope it the same changes were made to the ETMX BRS, raising the thresholds

 

H1 COC (COC)
ibrahim.abouelfettouh@LIGO.ORG - posted 16:36, Thursday 11 June 2026 - last comment - 17:35, Tuesday 16 June 2026(90600)
Mystery Spots/Streaks on BBS01 AR Side

Ibrahim, Betsy, Anamaria

Upon first in-chamber BBS01 inspection, we found 3 large clumps of spots approximately 100mm from the edge. We're consulting GariLynn at CIT for steps on how to clean.

Acetone swab: We tried to go over the spots with a cotton swab with acetone, but the spots remained.

First contact: We then tried to first contact a small portion with one thin layer, but the spots remained.

While there's no evidence that the beamsplitter was contacted, dinked, touched or scratched in anyway, this might be a cause for the damage. There is texture to the spots upon brushing them with a swab and while it seems more likely that these are above the surface, we are not totally sure.

Hypotheses (and their problems)

1. Peek In-Vac cable scratch: maybe an in-vac cable fell on that area but they would have had to imprint multiple times with some force to show something like this. 

2. Falling foil: maybe a piece of foil fell onto the surface and scratched it that way? No foil was used or wrapped at height during BBS and again, the foil would have had to fall with some heft.

3. There-the-whole-time: Maybe the spots were there the whole time and are invisible to non-chamber conditions. Because this is on the AR side, there is no good scatter plot of the surface. Since we did not see this in normal light conditions, but immediately saw this in chamber (dark) conditions, this may have been there all along. The spots are quite large (as attachments show), so this makes that less likely.

4. Dry first contact: Maybe it's dry first contact? We went over some of the spot with acetone but it stayed. We also first contacted a thin layer on one part but it stayed. The nature of the spots do look like they're small first contact bubbles. We found the first contact sheet that we used on that side and indeed, there are some similar streaks in size but nothing conclusive. We're looking at matching the spot with the first contact to see if there is a streak in this region. Problem is - first contact wouldve come off quick with the acetone treatment. So this is also not likely it.

What to do next:

- Analyze with Dino-Lite: We're going to zoom in on the spots with our DinoLite mount to get a better look. This could tell us if they are truly scratches or stuck particulate.

- Match first contact sheet with spots: Seeing if these spots were visible during FC (done on May 6) - alog 90149. Nothing visible. 

- Anamaria suggested at any rate shining a gaussian beam at it to analyze the damage in a short experiment to characterize. 

Images attached to this report
Comments related to this report
ibrahim.abouelfettouh@LIGO.ORG - 17:35, Tuesday 16 June 2026 (90639)

Ibrahim, Betsy

First, we imaged the spot, which yeilded these attached pictures of what look like... specks. No idea what these may be.

We then went over the spot with some thicker first contact, which did not remove any of the specks.

We recieved the procedure for spot-water cleaning which is the only last thing that we're thinking of trying.

In the attachment, the thinner lines are dry acetone and can be removed. Focus on the brighter dots instead.

Also adding a "map" of our AR side features thus far. I will digitize it and add this as an alog/DCC of its own once we're done with optic inspection.

Images attached to this comment
H1 CDS (SPI)
filiberto.clara@LIGO.ORG - posted 17:19, Wednesday 10 June 2026 - last comment - 21:28, Tuesday 16 June 2026(90585)
SPI Fiber Cover Installed

A plexi security cover was installed over the SPI Laser Chassis. Cover will be locked under normal operating conditions.

Images attached to this report
Comments related to this report
jeffrey.kissel@LIGO.ORG - 21:28, Tuesday 16 June 2026 (90646)
More pictures of the plexi-glass hatch. It secures to the chassis via screws and stand-offs, and has side openings. The box is merely trying to satisfy the "requires a tool to detach the fibers" criteria to make the system laser safe. The key will live in the control room lock box with all the other laser safety keys.
Images attached to this comment
H1 TCS
ibrahim.abouelfettouh@LIGO.ORG - posted 16:04, Thursday 16 April 2026 - last comment - 08:38, Wednesday 17 June 2026(89926)
TCS Chiller Water Level Top-Off - BiWeekly FAMIS 28639

Closes FAMIS 28639

Last checked in alog 89720

TCSX read 30.8 - nothing added

TCSY read 10.6 - nothing added\

No water in small cup under the slow leak

TCSX is reading HIGH PRESSURE FAULT. See attached picture. 

Images attached to this report
Comments related to this report
camilla.compton@LIGO.ORG - 17:25, Thursday 16 April 2026 (89931)

Betsy and I locked and tagged out the CO2X chiller, it will remain off until all needed repairs and safety documents have been completed next week. 

At 15:44UTC the chiller tripped off with a HIGH PRESSURE fault, as found by Ibrahim.  The CR verbal machine also alerted Ryan with a "low flow" warning.

I went out to the LVEA inspecting the pipes and found that the outgoing CO2X line was disconnected at the quick-connect, image. There was no water on the floor, so the quick-connect did it's job. Maybe this was already loose and we need to add the the pipe inspection FAMIS to inspect these connections, but. there was also lot of work in that area today. I inspected and reconnected the quick-connect, it did not seem damaged.

At out weak point in the chiller lines at the flexible baffle in the pipe bridge, the plastic sheeting that had been attached to catch any spilled water had a small amount of water in it photo, but none leaking out. Expect this water would have been pushed out a small break in the rubber while the chiller was trying to push water around the incomplete lines before the high pressure sensor in the chiller tripped it off. We will inspect and probably repair this part next week. In the meantime with water dripping out of the pipe bridge connection, we are fine to leave the chiller locked out with water in the lines. 

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camilla.compton@LIGO.ORG - 11:07, Monday 20 April 2026 (89949)

TJ, Camilla. Trending the pressure values doesn't tell us much. The chiller appears to go to the high pressure fault and trip off before the  pressure channels register a high pressure, see attached. ANALOG1 PSI starts at 65 PSI and ANOLOG2 started at 26 PSI, after the chiller trips off, these increase to 6500 PSI (unphysicial) and 44 PSI. The chiller must have an additional pressure sensor it uses to trip off. Current settings are to trip off at 80 PSI, see FRS 30283.

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camilla.compton@LIGO.ORG - 08:38, Wednesday 17 June 2026 (90650)

Randy built a unistrut protective barrier around both CO2X and CO2Y water pipes to protect them from this happening in the future. Photos attached. 

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