TITLE: 01/09 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 124Mpc
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 9mph Gusts, 5mph 3min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.63 μm/s
QUICK SUMMARY: Locked for 16 hours, useism up slightly from yesterday. The range has been trending down and we've been going in and out of Observing since Tony had to intervene. Looks like something in the squeezer is unlocking. It just unlocked again as I'm typing this up. Investigation ongoing.

TITLE: 01/09 Owl Shift: 0600-1530 UTC (2200-0730 PST), all times posted in UTC
STATE of H1: Observing at 155Mpc
CURRENT ENVIRONMENT:
    SEI_ENV state: USEISM
    Wind: 6mph Gusts, 4mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.53 μm/s
QUICK SUMMARY:
When I was first woken by the H1, we were in Nominal_Low_Noise, but not observing.
I noticed that the SQZ_MANAGER had an issue.
I was Very much not awake yet, So I just watched SQZ_MANAGER LOG and the SZQ_MAN states and observed the following:
SQZ_MANAGER couldn't get all the way up to FREQ_DEP_SQZ[100] and would hit FC_WAIT_FDS[64] and then drop down to FDS_READY_IFO[50] again.
I then started to read read the error messages we were getting, some beam diverter messages that would flash up quickly.
I then started to read some alog about recent SQZ issues.
I saw this alog from Camilla, which links to Oli's, but I wasn't sure if I was having the same exact issue.

But it did kinda point me in A direction.
I then checked the SQZ_LO_LR and the SQZ_OPO_LR  Guardian nodes & Logs and Init'ed SQZ_LO_LR. This did not solve the issue, but I tried other things from Oli's alog like requesting RESET_SQZ_ASC & RESET SQZ_ANG . I stepped away after hitting init on SQZ_Manager, to wash the sleep from my eyes and it was relocked when I came back. 

TITLE: 01/09 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 157Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Very quiet shift with H1 staying locked the whole shift and one BBH candidate event. H1 has now been locked for almost 7 hours.

• 01:06 - Candidate event S250109f

TITLE: 01/09 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 158Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: One lock loss with an automated relock, and some SQZ tuning on the prior lock. Other than that it was a quiet shift.
LOG:

• 1633-1635 Out of Observing to adjust SQZ OPO temp
• 1808-1812 Out of Observing due to SQZ unlock
• 2130 lock loss
• 2312 Observing                                                                      

TITLE: 01/09 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 161Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 4mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.48 μm/s
QUICK SUMMARY: H1 has been locked for just over an hour.

• Wind is low, microseism just around 90th percentile
• All other systems nominal

For reference here is a link with a summary of somewhat recent status for the LIGO SUS Fiber Puller:  alog #80406

Fiber pulling was on a bit of a hiatus with a busy Fall/Winter of Ops Shifts and travel.  This week, returned to the Fiber Puller lab  to pull as many fibers as possible (have some free days this/next week).  Thought I would note today's work because of some odd behavior.

Yesterday ended up spending most of the time making new Fiber Stock (we were down to 2, and about 12 more were made).  Also packaged up Fiber Cartridge hardware returned from LLO and stored here to get re-Class-B-ed.  Ended the day yesterday (Jan7) pulling 2025's first fiber:  S2500002.  This fiber was totally fine and no issues.

Today, I did some more lab clean-up but then around lunch I worked on pulling another fiber. 

Issue with RESET Position

The first odd occurrence was with the Fiber Puller/Labview app.  When I RESET the system to take a fresh new Fiber Stock, the Fiber Puller/Labview moved the Upper & Lower Stages to a spot where the Upper Stage/Fiber Cartridge Bracket was too "high" wrt the Fixed Lower Bracket---so I was not able to install a new Fiber Stock.  Closing the Labview App, and a couple of "dry pulls" later, I was FINALLY! able to get the system to the correct RESET position.  (not sure what was the issue here!)

Laser Power Looks Low

Now that the Fiber Stock was set to be POLISHED & PULLED, I worked on getting the Fiber Stock Aligned (this is a step unique to our set up here at LHO).  As I put CO2 beam on the Fiber Stock, the first thing I noticed was very dim light on the stock (as seen via both cameras of the Fiber Puller).  This was at a laser power of 55.5% (of the 200W "2018-new" laser installed for the Fiber Puller last summer).  The alignment should not have changed for the system.  I wondered if there were issues with the laser settings.  I notice I had the laser controller at the "ANV" setting---it should be "MANUAL".  But nothing improved the laser power.  

Miraculously, the laser power (as seen with the cameras) returned to what I saw yesterday for S2500002, so I figured it was a glitch and then moved on to a POLISH, but within a few minutes and being mindful of the laser power on the stock on the cameras, once again the laser spot became dim.  But I did nothing and just let the POLISH finish (about 15min).  Fearing there was power-related issue, I decided to run the Pull (takes less than a minute), but at a higher power (75% vs 65% which had been the norm the last few months).  

S2500003 pulled fine and passed.

I thought we were good, but when I set up for S2500004, I noticed more low and variable laser power.  I worked on this fiber later in the afternoon after lunch.  This one started with power which looked good to me (qualitatively), so I continued with set-up.  But in a case of déjà vu, the laser power noticeably dipped in power as seen via the cameras.  For this fiber I decided to continue, but since S2500003 had a "low-ish" violin fundamental freq (~498Hz), I figured I would return to a power of 65% for the Pull (hoping the laser power was hot enough for the pull (and not cool enough to cause the fiber to break during the pull---something which happened with our old and dying 100W laser we replaced in 2024).

Pulled the fiber and it all looked fine, profiled the fiber, and then ran an analysis on the fiber:  it FAILED.

This is fine.  Fibers fail.  Since Aug we have pulled 29 fibers and this was the 5th FAIL we have had. 

This is where I ended the day, but I'm logging this work only for some early suspicions with the laser.  Stay Tuned For More!

During yesterday's maintenance period, we removed the Inficon BCG450-SE pressure gauge that was on the C1 cross in the FC. This gauge has not been in use since the inital pumpdown of the filter cavity tube and was used in conjunction with the SS500 pump cart.

The +X RAV was closed, along with the redundant RAV before the inficon gauge. Gauge volume was vented and replaced with an o-ring angle vavle and KF40 to CF adapter. Newly install joints were pumped down and leak tested with HLD, and showed no He signal above the leak detector background, <1E-11 Torr-l/s. After leak check was complete, the +X RAV was opened to the main FC volume, redundant RAV remains closed as a pump-out port.

This gauge is now a spare for the HAM6 gauge replacement to follow.

FAMIS 28456

Both CO2 lasers have generally been increasing in output power on each relock. The increased CO2-Y laser temperature lines up clearly with decreasing chiller flow rate on a few occasions in the past month.

1420407046

ETMX glitches in the output drive <1s before lock loss.

Famis 26025

CPS_spectra_13:25-01_08_2025.pdf

Wed Jan 08 10:07:22 2025 INFO: Fill completed in 7min 19secs

Gerardo confirmed a good fill curbside. TCtrip=-60C, TCmins = [-93C, -90C] OAT (2C, 36F)

Our range has been slowly falling, so I followed alog80461 to adjust the OPO temperature. We dropped Observing during this time (out from 16:33:14-16:35:14 UTC), and it looks to have helped out range a bit.

In 81863 we looked a the RIN of the CO2 lasers on vs off. Today we repeated with PWM (from Synrad UC-2000), the noise level is considerably higher when PWM is on. Note that this isn't really the RIN as we're not dividing by the DC power.

Data saved to camilla.compton/Documents/tcs/templates/dtt/20250107_CO2_RIN.xml and 20250107_CO2Y_RIN.xml

• Refs 0-3: Laser on CW
• Refs 4-7: Laser off.
• Refs 8-11: 50% PWM (CO2X laser locked, CO2Y unlocked)
• Refs 12-15: 25% PWM (CO2X laser unlocked)
• Refs 16-19: 95% PWM (CO2X laser relocking)
• Refs 20-23: Laser on CW

The CO2Y plots also show the dark noise as there is no photo detector plugged into CO2Y_ISS_IN.

• CO2Y plots: AC only, DC only, all.
• CO2X plots: AC only, DC only
  • It's strange that there more CO2X DC noise with the laser off and that the 25%, 50%, 95% PWM's are the opposite way around for the AC and DC outputs.

For some of the CO2X data, the CO2 guardian was relocking (sweeping PZT), noted above.

WP12271

We investigated the SHV cable connectivity between the Ion Pump Controller at EY and the Ion Pump at Y2-8 checking for faults.  We did not detect any obvious faults, we did detect the prior splice which was installed back in 2016.  We used the Fieldfox in TDR mode with a 1.2 meter launch cable in low pass mode. I have attached scans of these findings:

First photo is a shot from the Controller, there is a large impedance change at 19 meters from the connection point, this is the same location of the splice made in 2016, the repair looks like we would expect a splice to look.
https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=28847

Second photo is a shot from the Ion Pump back to the end station.  There is a very small bump at 20 meters from the ion pump that is real, but is very very tiny, could be a kinked cable, but not enough to cause issues.

Otherwise, the cable looks fine.  Future testing is warranted.

M. Pirello, G. Moreno, J. Vanosky

Looked at the spectum of th 50W CO2 lasers on the fast VIGO PVM 10.6 ISS detectors when the CO2 is locked (using the laser's PZT) and unlocked/ free running: time series attached. Small differences <6Hz, see spectrum attached. 

Because we moved the OPO crystal position yesterday, 8045, the crystal absorption will be changing for a few weeks, and we will need to adjust the temperature setting for the OPO until it settles, as Tony and I did last night. 80455.  Here are two sets of instructions, one that can be used while in observing to adjust this, and one that can be done when we loose lock or are out of observing for some other reason. 

For these first few days, please follow the out of observing instructions when relocking, if this hasn't been done in the last few hours, and please try to do it in the last few hours of the evening shift so that the temperature is close to well tuned at the start of the owl shift.

Out of observing instructions (to be done while recovering from a lockloss, can be done while ISC_LOCK is locking the IFO) (screenshot) :

• Make sure that ISC_LOCK will not set SQZ_MANAGER request to INJECT_SQZ, by setting the request to ADS_TO_CAMERAs or any lower state.
• From sitemap, SQZ_OVERVIEW, set SQZ MANGER request to LOCKED_SEED_NLG.
• from the purple !SQZ scopes button, open the NLG scope
• Once the SQZ manger is in LOCKED_SEED_NLG, you should see that the red OPO_IR_TRANS trace on the scope is oscillating.  Adjust the OPO temperature using the slider which is right under the purple SQZ scopes button, to maximize the peak of the oscillations. 
• SET_SQZ MANGER request back to FDS_READY_IFO, and once that's ready you can set the ISC_LOCK request to nominal low noise.
• Before going to observing, you can adjust the squeezing angle by requesting SQZ_MANAGER to SCAN_SQZANG.  It is best practice to do this after the IFO has thermalized, but it can be done early in the lock.  If lock stretches are long and this has been done only early in the lock, it may need adjusting for a thermalized IFO.  Right now the squeezing angle has a strong frequency dependence early in the lock stretch, so let's not adjust it until the IFO has been locked for at least an hour.

In observing instructions:

Both the OPO temperature and the SQZ phase are ignored in SDF and can be adjusted while we are in observing, but it's important to log the times of any adjustments made. 

• To adjust the temperature in full lock, go to the purple SQZ_SCOPE button and choose the OPO temp scope, adjust the OPO temperature to maximize CLF_REFL_RF6_ABS (the green trace). 
• After doing this it might be necessary to adjust the SQZ PHASE, which can be adjusted in steps of 5 degrees or so.  Set this to maximize the squeezing level, which you can do by watching the DARM FDS dtt template.  It is available from the SQZ DTT purple button, or on NUC33.  It is easiest to adjust this for high frequency squeezing (around 1kHz), this should get you close to good squeezing at 100 Hz.

Changes made to make this easier (Thanks Corey for beta testing the instructions):

•  I've commented out the request to SQZ_MANGER that ISC_LOCK makes in low noise length control, because that took control of the squeezer from Corey when he was giving these instructions a trial.
• The OPO temp is not monitored in SDF
• I removed the goto= True from the LOCK_FSS state.  This will force SQZ_MANAGER to go through down after the NLG measurement (and turn off the seed PZT ramp).