"It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife"

- Jane Austen, opening line of Pride and Prejudice

But unfortunately for both us and them, sometimes those men are winged termites in the Optics Lab.

As Elenna and I were cleaning up our work in the back optics table this afternoon, we noticed a few winged termites, and ended up finding maybe almost 10 in total walking around on the floor in the back area of the optics lab near the wall mounted cabinets between the two cleanrooms. We got rid of them but couldn't find where they had come from. I'm wondering if they're maybe coming from an opening under one of those cabinets? Last year this happened but those came out from under the flow benches along the wall - not sure if this is part of that same colony that survived or a different colony.

To summarize the ongoing issues from yesterday:

• we determined that the cables (DCPD and PZT) attached to each OMC are mixed up
• one cable has incorrect wiring, because the ground pins are not where they should be (pin 2 and 5 are ground instead of 6 and 9)
• we're not sure if the polarity is correct on the diode

Keita and I have decided that swapping cables can possibly be done without removing the DCPDs. We're going to determine OMC A and OMC B based off of the PZT cable, and then swap the DCPD cables. We're waiting to hear the final verdict on the diode polarity to do pin adjustments and cable swapping.

In the meantime, Oli and I installed OMCB on the suspension and bolted it down using the OMC alignment template. We have placed the butterdishes over OMCA and B, but we haven't secured them yet with viton clamps while we continue to do work on the OMCs. The cables are only loosely clamped.

Next, Oli and I worked first contacting the remaining optics for BHSS- two HRs and one 50/50 splitter. The HRs were finished today, installed in their mounts, and placed randomly on the platform. The 50/50 splitter is still being FCed and should be ready in the morning. Once that optic is installed, we will proceed with the alignment of the OMCs and optics.

One vertical clamp is still missing from OMCB, but we should be able to install it once the helicoils and such arrive.

Sheila, Camilla.

We decided to pause on looking for the FC alignment and look at SQZ alignment into the IFO. To check our irises and possibly look for scattering shelves. 

Locked SEED_DITHER with 75mW into fiber. Moved ZM3 to get OPO_IR PD up to max 0.9mW. Opened BeamDiv and after aligning SRM, mis-aligning SR2, could see beams on AS_A,B and C. AS_A and B had a similar size ~60 to reported before (e.g. 86965), but there was less power on AS_C: 4e-4 rather than the previous 7e-4.

We used Ryan's DRMI time from 89573 to put OM1, OM2 and SRM back. The with the SQZ SEED injected, we tried to use SQZ centering loops to center on AS_A and AS_B, this didn't work quite as expected. ZM4 kept saturating although these loops had worked Janaury 19th, before moves were done on the VOPO to help with clipping e.g. 88966.

Then went back to alignment on Jan 31st with 88976 with ZM1,2,3, 4,5,6 FC1. And took OM1,2,SRM to the January 19th positions. However here we saw no light on SQZT7 OPO IR PD, HAM7 WFs or in HAM6 on the AS_A,B,C diodes. This was done at 23:10 UTC. Comparisons of osems attached. The sliders to get these osems values are fairly different, see attached, so I also tried going to these slider values, that gave me some light on SQZT7 IR PD, HAM7 WFS and FCES with SEED injected, see attached. HAM6 AS diodes saw nothing. 

TITLE: 03/25 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: GV7 is still broken and will not hard close, HAM1 vent prep work, the PSL incursion was completed, and the BHSS work continues in the Optics lab.
LOG:

• 19:19 UTC Tony keyed off TCSY

J. Kissel, M. Pirello

While in SUS-R2 and thinking SPI, and looking at the proposed rack layout from G2401479, and accounting for all the SUS (BBSS, LO1, LO2) that's incoming for O5 -- I found that SPI can have a bit more space if we just move the SUS-PR3 optical lever whitening chassis up 5 U-heights from "32" to "27." I put the u-height in quotes because this is an old style rack with the u-heights labeled from top down, rather than the bottom up per industry convention. I would have and could have gone higher, but the 27 slot already had mounting clips in it, so I went there. We can go as high as "25" if need be in the future.

Pics of before vs. after are attached.

F. Clara, J. Kissel, S. Koehlenbeck, J. Oberling, M. Pirello
D2400110

Today we picked up where we left off with the install of SPI into H1. 
Where we last left things, we'd installed a new SPI pick-off of ALS/SQZ beam in Apr 2025 (see ECR E2400083 and results in LHO aLOGs 83989, 83996, 83978). Back then, we had ended the work with the input to the fiber collimator within the PSL dumped.

With Jason and Sina in the PSL, we confirmed that the SPI path was still blocked. 

However, we also realized/remembered/confirmed that the entire ALS/SQZ/SPI path had 25% less power -- We've been running the PSL at lower power allocation downstream of the PMC since Sep 2025 to prevent issues we'd found with the currently installed EOM after a power outage triggered a dust monitor to spew out dust into the PSL (see that saga in e.g. LHO:87109 LHO:86966). They found the power at the SPI pick-off was 140 [mW] instead of the 188 [mW] we left in Apr 2025 (see LHO:83996).

(Using labels in the half-up-to-date drawing D1300348)
Jason and Sina rotated ALS-HWP2 upstream of ALSPBS01 to restore the nominal 50 [mW] into the ALS/SQZ pick-off and ~200 [mW] (190 [mW] measured). This means there's ~50 [mW] less out to ALS / ISCT1 than before today.

Then with the SPI pickoff still dumped, we installed a 30 [m] patch cord*** from the PSL optical table, out the mouse hole between the +X wall of the PSL enclosure and HAM1, then up running along the upper racks to waterfall down at SUS-H2. The fiber sits within the typical orange tubing. Per D2400110, this is SPI_PSL_001, and it's labeled as such on both ends.

After install, I connected the SUS-R2 end to a Thorlabs S121C power meter with S120-APC2 fiber adapter. 
With this installed (making the system laser safe at SUS-R2 end), Jason/Sina unblocked the SPI pickoff input. 
With 190 [mW] in, we measure 187 [mW] out on the other end. 98% transmission, pretty excellent. Almost unbelievably excellent but we weren't rigorous with our uncertainty and systematics.

Happy with this result, we then blocked the SPI path again, and re-capped the SUS-R2 end for final dressing in the racks.
We'll unblock again when we're read to connect it to the Laser Prep Chassis.

***Patch cord details:
Manufacturer DIAMOND
DIAMOND Part Number: ENS/1094388
Customer Part Number: 9711228
Patchcord SM L=30 PM
2xFC 2mm APC (i.e. 2mm narrow key FC/APC on both ends)
tran 6,6/125/245 PAND 980nm



 

WP 13105
WP 13113

During the last two days CDS EE has completed the following:

1. SPI Optical Fiber pulled from the PSL enclosure to SUS-R2
2. Heliax cable pulled from ISC-C3 to SUS-R2, part of SPI
3. Two Heliax cables pulled from ISC-C4 to ISC-R2, part of JAC
4. Cabling disconnected to IOT1 and ISCT1

This completes dirty work over HAM1 and HAM2. In the next two weeks, will close out work in SUS-R2 before HAM3 is vented.

List of items needed for SUS-R2:

1. Install power supplies in CER Mezzanine
2. Terminate power cables and install junction box
3. Terminate Heliax cable
4. Test and install two SAT Amp Chassis
5. Installation of DC sequencer
6. Install QOSEM Sat Amp
7. Pull cabling from SUS-R2 to HAM3
8. Installation of SPI electronics

F. Clara, J. Kissel, J. Oberling, M. Pirello, T. Sanchez, and R. Thompson

S. Muusse, C. Compton

0920 QCL unit failure summary:

We were beam profiling the laser and I had the profiler ~8” from the laser head, with a steering mirror to steer onto the scanner. Laser was at 1A. I blocked and unblocked the beam but as it was unblocked there was a beep and there laser controller turned off with message “LD output voltage protection was tripped”.

I then turned controller off and back on again with power down to 0.5A and it would not turn on.

Camilla then came into the lab, we turned off and unplugged controller. It was turned on again, would not turn on. Remembering LLO's issues, on the Temperature Protection screen we eased the +-5 deg requirement to +-6. Laser then appeared to turn on with “laser current reading 0.500 A” and “laser voltage reading 10.440V”, temperature 25deg. However no beam was coming from the laser.

We then turned off and on laser. Again appeared on but no beam, slowly turned up current from 0.5A towards 1A, at 0.84A controller beeped with “LD output voltage protection was tripped” message again.

QCL Unit q-parameter dependance on laser temperature:

Unit failure happened while profiling the laser to check if the q-parameter of the QCL has a temperature dependence. This profiling was done largely at a 23mm offset with one point near the waist. However, there was not an opportunity to take more measurements around the waist in this new data because of the failure which may cause some inaccuracies in the fitted q. I used a non linear fit where M2=1. This is consistent with the fitting by Matt. His measurements were completed at 20 deg but after advisement from thorlabs we have increased operating temperature to 25 deg. 

With the new q factors there is slightly better agreement between the fitted q-parameter for L2 and the model.

Vertical

Horizontal

Wed Mar 25 10:11:55 2026 INFO: Fill completed in 11min 52secs

Sheila, Camilla

While we had good green (20) and IR (1) FC flashes, we had to move 100urad in ZM3 positive PIT to get any light on SQZT7 OPO IR PD, see -2h30 on screenshot.

We then walked ZM1 and ZM2 both in negative PIT (which seems a bit weird but worked) until we only had to move ZM3 13urad to get light on SQZT7. However in doing this move, we lost the majority of IR light and some green light, see t-cursor #1 of screenshot. I injected the SEED beam at this point and the IR FC camera looked again like a strange cross or swallow bird.  I hoped to move ZM3, FC1 and FC2 to bring back IR light but wasn't able to.

I was able to get good green flashes simultaneously with SQAT7 IR light but then I had no IR FC light,  see t-cursor #3 of screenshot, 22:35UTC.

Vicky reminded us of 2022 when we had to pico to get FC green/IR co-resonance: 66017, 66281

TITLE: 03/25 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: CALM
    Wind: 5mph Gusts, 2mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.23 μm/s 
QUICK SUMMARY:

• The JAC and IMC were held DOWN/OFFLINE overnight (IOT1 is disconnected)
• Test stand craning, cabling, SPI, and BHSS work continues
• The CEBEX workshop continues in the front MPR

The JAC seems to be failing to lock. I'm not sure why, but since it's just scanning I assume it's fine for the night. But, if someone with more JAC experience thinks it's useful to log in and set it to DOWN for the night, that would be good.

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

Last Friday we tried to "hard close" GV7, but we only achieved a "soft close" status.  After looking at the system that uses instrument air at the gate valve, we did noticed that the solenoid valve to "open" and "close" the gate valve was "leaking" air, lots of instrument air, to fix the air leak we decided to replace the solenoid valve with a new one.
Then when it was time to "hard close" GV7, its pressure regulator broke, we were not able to open the regulator.  We ordered a couple of new regulators and should be here on Wednesday.  Meanwhile we are going to "hard close" the gate valve using a bottle of nitrogen.
Attached is a photo of the broken regulator, yes the knob is off, but the metal piece within is free floating and not able to do its job.

We previously reported that the wiring to ground on the OMCA DCPD dsub9 cables seemed odd, see 89562. There appears to be two conflicting diagrams of the pin wiring, D2200276 and D2300119. Neither of these diagrams follow the correct pin naming practice either.

Today, Oli and I checked the ground connectivity for the OMCB DCPD dsub9. The case ground is wired to what is labeled pins 6 and 9, according to both of the diagrams above and also proper convention. However, this is different from OMCA, where the case ground is wired to pins 2 and 5 (following the incorrect naming of the diagrams above), or pins 1 and 4 (following correct naming conventions).

So either way, we have two different wiring set ups for OMCA and OMCB. We have only checked the ground pins so far, and it seems like we should confirm the cathode and anode wiring as well.

To summarize:

- we have two different diagrams for pin wiring

- OMCA and OMCB are wired differently from each other

- the diagrams are not following proper pin naming convention which is making this more confusing

Hepi Pump Trends (Monthly) Famis 39954:
 

On Jan 26th the HPI-PUMP_EX_PRESS1_PSI started rising in maximum pressure. and on  maybe feb 2nd it started getting worse. Seems like it has plateau-ed on Feb 16th, but the Pressure still remains elevated.

That channel back in Oct was between 92.4-92.6 PSI. 
And now it's between 91.9 - 93.5 PSI. I'm not sure if this is out of bounds for HEPI.