Dry air skid checks, water pump, kobelco, drying towers all nominal.

Dew point measurement at HAM1 -43.9 °C.

FAMIS - 26378 Checking HVAC Fans Vibrometers.

Fans dont look too bad aside from H0:VAC-MY_FAN_270_1_ACC_INCHSEC which seems to be a  Noisier fan.

TITLE: 05/15 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: 12mph Gusts, 8mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.08 μm/s
QUICK SUMMARY:

LVEA is LASER Safe. Hartman Lasers are on but are Eye safe and are ~780nm green/blue in color.

HAM1 ISI is currently unlocked.

Today's  Agenda:
CS:
HAM1 optical Alignment checks
HAM1's Glamour shots.
HAM1 Ground Checks.
Cable Tray work.
GOUI phase measurements in the output arm
TCS work?
 

EX
More wind fence work.

EY
SEI BRS work.

Now that ISC is done with their alignment, I have been working on testing the ISI. Last night TJ and I unlocked and balanced the ISI, I did some quick tests to make sure the actuators were pushing where I expected them and found the horizontal and vertical actuator for each corner was swapped, so I switched the cables at the chamber. This morning I did some tests like range of motion and CPS linearity and some quick spectra to check that all of the sensors looked more or less the same and a quick set of tfs to look for rubbing. Now starting my long overnight tfs, so hopefully there are no big eqs overnight. If those go well, I hope to have everything for the testing report by the afternoon tomorrow.

Attached images are some of the tests I did today. First image is CPS linearity, which looks kind of ratty because I think the purge was too high, but otherwise looks okay. Second image shows unlocked asds for the CPS, GS13s and L4Cs. No glaring issues, but the kind of noisy V2 GS13 and CPS made me think some rubbing or high purge was happening. Last image is a set of tfs I used for chamber closeout comparing the measurements on HAM8 from last year to HAM1 today. Looks okay for a quick measurement.

Fil, TJ, Camilla. WP 12533

We turned back on the RH and SR3 heater chassis which were turned off for venting. After these were turned on, ITMX came back to it's nominal value of 0.44W/segment.

TJ and I played with the inverse RH filters for a while on ITMX (instructions 50777),  turning ITMX up to 0.5W for a couple of hours, it doesn't really make sense to us what it was doing as it drops the power lower than the requested power which seems un-intuitive 68549. Now back at nominal 0.44W/segment with the RH inverse filter guardian back to NOMINAL (off). 

ETMY had come back to the incorrect value after the April power outage (last saved Beckhoff value maybe), so TJ turned that back to the nominal 1.3W/segment on ETMY too. 

TITLE: 05/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
HAM1 Purge air has been turned Down.
HAM1 ISI is Currently Unlocked.
It got too windy to work on the Wind Fence  while elevated at EX, so wind fence work was postponed.
SEI BRS team found a broken cable on the BRS System.

TCS team Turned on the Hartman Wave front lasers. These are Eye safe lasers that have a power output of less than a mW. So if you see a blue-green ~780nm beam it MAY be from that.

Bees are still at EX.

LOG:                                                                                                                                                                 

Sheila D, TJ S.

Summary: the ALS arm guardians will now log the Beckhoff fiber locking error messages (untested though, testing later), and I've relaxed some of the thresholds set in Beckhoff. This is all nice, but I don't anticipate major gains from this.

Why: Our ALS locking has not been as reliable as it once was and has been one of the primary reasons for our locking not being fully autonomous. We have been discussing ways to help our ALS locking without large scale ALS table mode matching efforts, that would be very time and resource heavy, and has the chance to impact the ALS system negatively while we are still in a run. One issue that Sheila pointed out was that there were some times before this recent break that the Beckhoff automation code would flag some type of error and then stop the locking automation, the guardian node would see this and drop to the unlocked state and then start over. Sheila thinks that the Beckhoff errors are often based on far too strict of thresholds, and we should rely more on the guardian node for the error checking.

Guardian Changes: While the Beckhoff error codes for fiber locking are in the DAQ (H1:ALS-X_FIBR_LOCK_ERROR_CODE), this binary value needs a map to convert it back to something human readable. The guardian node doesn't look at these directly either, so we don't currently have an easy way to see what the Beckhoff automation is failing on...until now! The binary first has to be converted to hex, then the hex values and their associated error codes were found in a table from E1300482. I wrote a quick dictionary with a string message for the different binary values that are in epics. I've added this into the ALS nodes as a decorator to many different locking states. It will frequently check if there are any errors and log them so we can track what is happening a bit better. It won't be perfect though since it's just a decorator and it's possible that we will miss some of these error messages.

What codes have we been seeing? So in terms of error codes, what has been happening? In 2025, there was a trend in the X arm error codes that was seen during some times where ALS was fussy. Attachment 1 is an example where there is a "beat note out of range of frequency comparator" followed by a "laser error" code. This generally only lasts a few minutes though, and it looks like there were issues before these codes popped up. For the Y arm, the error codes are up for <1second and will often happen a minute or more after the arm loses lock, so I don't think this is too useful. The most common error codes that pop up are: Reference cavity transmission PD error, Reference cavity transmission below the limit, Beat note power too low.

Threshold Changes: One thing that has already been done was lower the PLL reference cavity transmission low limit (ref cav trans low limit) - alog83547. Today, I changed the PLL beat note frequency range from 3MHz-150Mhz to 2MHz-350MHz. The max frequency I saw was near 300MHz, so 350  seemed like enough to get it out of the way. Beat note minimum was already at -40dB, well out of the way already (see attachment 2 for examples). There might be some more places to relax the Beckhoff thresholds, but these related to the most common errors that we saw. Except for the very vague "Laser error" code. This will need more time to look into.

Ibrahim, Betsy, Oli

Yesterday Betsy and Ibrahim swapped the wire loops for gold-plated wire loops (84378), so today Ibrahim took some top to top transfer function measurements and I've analyzed them (2025-05-14_1400_X1SUSBS_M1_ALL_TFs).

I have also made plots comparing them to our last measurements from February (83075). The new wire makes basically no difference (NoPlatingvsAuPlating).

I've also compared this latest measurement to LLO's latest measurement, and they are matching pretty well (AcceptanceReview).

These have all been committed to svn as r12307 and r12308 for the loop plating comparison.

(CoreyG, MitchR, ChrisS, RandyT, JimW)

This week's wind fence work continues. With a couple of issues that continued from last week and were addressed:

1. Soft Sand-- This has been an issue because it is fairly easy to get aerial lift wheels stuck in the sand.  Because of this, and since the big rental aerial lift was in position near the 1st panel (or "southernmost panel"), it was decided to do this panel's rework in one shot (vs the usual procedure of doing a step for all panel positions, and then moving to next steps for all positions, and so on)
2. Bee Hive--Last Thursday, a beehive swarmed the wooden spool for the large wire.  A beekeeper was phoned in to help rehome this hive.  A beehive box was placed near the spool and today, this box was moved so the spool could be reinstalled in the trailer for use.

The first panel is mostly complete (on Tues) with one vertical cable remaining to be installed.  Old panels had thinner cables removed and are folded up for future availability and storage.

A water tank was delivered to EX (Tues) to allow daily soaks of the sand to help improve travel.

Today (Wed) was a windy day with sustained winds of around 15mph, so this morning mostly focused on non-at-height work.  The thick cables were cut for the remaining 3-panel locations

Attached below are the first set of transfer function measurement results for the Tip Tilt suspension PM1 in HAM1 chamber. The purge air flow in chamber was reduced to enable good coherence value and minimum cross coupling for this in-air measurements, and the results are very much visible when compared to earlier data (not posted here) which was very noisy. The plots attached below are for Length, Pitch and Yaw degree of freedom. Yaw dof. still shows some cross coupling/unwanted peak at 1.28Hz approximately, however it should go away in vacuum.

The templates for this measurement are stored at the following location,

/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/PM1/SAGM1/Data

2025-05-14_2100_H1SUSPM1_M1_WhiteNoise_L_0p01to50Hz.xml
2025-05-14_2100_H1SUSPM1_M1_WhiteNoise_P_0p01to50Hz.xml
2025-05-14_2100_H1SUSPM1_M1_WhiteNoise_Y_0p01to50Hz.xml

Hence, I can confirm that the suspension and the electronics chain is healthy.

Chiller pump 1 at Mid X was overhauled; bearings and seal were replaced, stator was cleaned, and impeller was inspected. Current wear ring is in decent shape and was left in place. Pump was reinstalled this morning. 

I branched and added some functionality to my misaligned GUI located on ASC IFO_ALIGN_COMPACTEST. I wrote another script to take a lock start and end and run the GUI every 5 minutes, take a screenshot then stitch them all together to make a gif of the lock so that we can see the changing alignments throughout lock stretches. It's a little slow, it was taking 20 minutes per hour till I realized I was redoing a large calculation each iteration unnecessarily, changing that brought it down to ~10 mins/hour of lock.

Here's an example gif of a short 2 hour lock starting at 03/30/25 18:13

Betsy, Ibrahim

Today, Betsy and I replaced the non-plated BBSS bottom wire loop with the gold plated wire loop, which was done successfully and took roughly two hours. We've confirmed the BBSS is centered and aligned. We will monitor and inspect the BBSS in the next few days and coming week. Stay tuned for new transfer functions etc.

Gallery of the wire loop below!

[Shoshana, Michael]

We've started preparing to install the BRS mass adjuster to the End-Y BRS. The plan is to follow the same procedure/same parts as the End-X install outlined in LIGO-T2400043 and SEI log 1886 (https://alog.ligo-la.caltech.edu/SEI/index.php?callRep=1886).
 We've taken apart the BRS and discovered that doesn't match the designs on the DCC. How the parts are arranged blocks access to where the pico-motor mount should attach, but we think we have a work around that should work.
The electronics/wiring of the BRS is as expected and we've finished all the wiring for the pico-motor so that it should attach to the feed through.
Assuming all goes well we plan on installing the mass adjuster parts and begin testin.

Sheila, Betsy, Tyler, Oli, Jennie, Camilla, 

Day 1: 84193, Day 2: 84228, Day 3: 84230 and 84239, Day 4: 84274, Day 5: 84292, Day 6: 84314, Day 7: 84334

PSL ALS: we decided that the PSL ALS path was too close to the edge to the VP (84334) we tried moving M13 so the beam traveled in-between M11 and L2 but this didn't give enough separation at the bottom pericope mirror of ISCT1. We then put M1 back to a similar position to wear we started an decided that it was good enough away form clipping the VP. Photos attached of M15 location, beam on M15, beam next to L2, VP simulator, UPM, LPM.

Betsy, Camilla, Keita

We ended up using pico in HAM3 to bring down green ALS beam as well as IR POP rather than raising the top periscope mirror after confirming that it was safe to do so.

We first confirmed that the X arm and corner alignment were still the same as yesterday. X arm was still locked to 00 green, and when I misaligned PRM the IR flash in H1:LSC-TR_X_IN1 was reaching 0.8 or more.

We convinced ourselves that the alignmernt was reasonable and probably similar to the alignment before the vent, that the ALS beams were pretty high but was still hitting the top periscope mirror before just like ALSX beam is as of now. We discussed the use of the pico in HAM3 (instead of moving the top periscope mirror up) and decided that it's OK to do so as far as the IR beam is far from clipping somewhere in HAM2.

We moved the HAM3 pico for PIT in "Down" direction by 700 counts and the IR beam position looked about right. We moved the pico further down by 1000 counts (that's the total of 1700 counts down from the initial state) and the IR beam missed the bottom of the top periscope mirror but no sign of clipping in HAM2, so we were comfortable to go 1000 counts "UP" and search for an optimum positision. In the end we ended up going back to 700 counts "Down" relative to where we started.

Sheila and Camilla adjusted top and bottom periscope mirror. M10 (dichroich) was also touched up. Steering mirrors for in-air beams were also roughly adjusted, These are M7 (for REFL air), M11 (for green ALS), M13 (for IR ALS beam from the PSL) and M16 (for POP air).

Now we're ready to move ISCT1L in position to confirm that all beams hit the periscope mirrors on the table.

Betsy, Camilla, Keita, Jason This morning, we took a closer look at eh small PSL-ALS beam path hitting the 1 and only mirror in HAM1 before heading to IOT1. It looked a bit clipped/elongated and was coming out of the light pipe toward the -Y side and veering off course onto the table (when compared to the new layout map). Given work on the path on the PSL table (for SPI), Jason and Keita went in to the PSL and revisited how the beam launches at the periscope. They could see scatter somewhere in the light pipe so it was probably clipping in there. Using the top ALS periscope mirror, Jason was able to yaw the beam back to the designed position of the mirror in HAM1 (Keita on the phone with Jason in the box, relaying to Betsy who moved the mirror and beam dump on HAM1). Now the beam looks nicely round, more centered in the entry viewport window, and runs along the table per the map we are aligning to D1000313-v19. We pointed the steering mirror so the beam leaves the table to also match the map. 

Next up is the X-arm peek and tweaking of alignments to get onto the IOT1 periscope mirrors.