Sheila, Betsy, Keita, Camilla. Continuing from 79373. Measured in 2021 in the lab in 59410.

Betsy and Sheila set up of the power meter in location B of 79373 with the wave-plate rotated such that the beam is visible. Distance between OM1 and retro-mirror is ~350mm, before the fast shutter.

The retro-refection wasn't perfect. Betsy and Sheila found that the HAM5 iris centered on the forward aux laser isn't well centered on the beam retro-reflected from the mirror in HAM6. This made it hard to block the ghost beam (direct reflection, no change in polarization) without also blocking the retro-beam that we want to measure. There is also a bright rejected beam headed to ZM6 which is only there as the waveplate is changing polarization is making some of the beam rejected by the TFP.  They touched the retro mirror to improve it.

They alternated power measurements from position B (the beam that should be isolated by the OFI) and then position A (to measure the power from the laser). Used 10 seconds of statistics mode data for each with the Thorlabs power meter.

Starting measurements at 10:01 PT:

• Position B (isolated by the OFI): 1) mean 1.025uW stdev 25.55nW, Blocked/Background 809.0nW stdev 2.227nW, 2) mean 1.056uW stdev 12.11nW, Blocked/Background 845nW stdev 8nW, 3) mean 1.015uW stdev 1212nW, Blocked/Background 822nW stdev 4nW
• Position A (power from the laser): 1) mean 7.589mW, stdev 96.83uW. Blocked/Background 685.7nW stdev 12nW 2) mean 7.708mW, stdev 41.13uW 3) mean 7.742mW, stdev 47.93uW

Similar measurements by LLO in 58791 and 2021 from LHO in lab 59410.

AS_C sees this beam, measuring 360uW. It is not centered, -0.4 in Pit and -0.4 Yaw, see attached. When we set up the aux laser it was also off in this direction (-0.6, -0.6) 79300: similar enough.

Betsy and Shieal added a waveplate before the OFI in the AUX path and checked that the forward KTP rejected beam to OFI_B was seen, attached.

In parallel, we turned on the SQZ laser and checked that the SQZ dither lock was stable (0.94mW on OPO_IR_PD) with 75mW of SEED injected. Keita and I opened SQZT7 and adjusted ZM4 and ZM5 to be better centered on the irises. We still didn't have much beam on AS_C but after I further adjusted ZM4 (sdf's not saved), we could see it, see attached.

Betsy is working on replacing the osem magnet I knocked from it's correct position in 79316.

LVEA LASER Safe transition:
Oli and Ibrihim have transitioned the LVEA to LASER safe.
Work Permit: 12011

Dew point measurement taken this morning read at -43.9 ^oC.  Measurement taken before any activity inside chambers.  Soft covers were on HAM5 and HAM6, HAM7 is isolated and a bit pressurized.

Wed Jul 31 08:08:59 2024 INFO: Fill completed in 8min 55secs

Gerardo confirmed a good fill curbside.

TITLE: 07/31 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 10mph Gusts, 6mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.07 μm/s
QUICK SUMMARY:
H1 is still down for maintenance:
Expected LVEA work today as descriped in the LHO  HAM5 V1 Document ES400260: 

Measure Isolation - new simpler plan suggestion from LLO (cube between SRM and OFI…)  Backup - Need Aux laser in HAM6 as LLO#58791, 58848
If out of spec, adjust TGG crystal location (slots in mount)
Inspect/deal with beam dumps if not done already

Before closeout
Robert in-chamber pictures
Finish testing Fast Shutter, trigger HV
See HAM6 closeout checklist
Rebal OFI
Reinstall OFI Glass shroud
Check AS and WFS, Viewport simulator to check beams coming out
Unlock ISI
Unlock retest SUS/SEI
HAM5 closeout FIRST CONTACT ON SRM 1” WITNESS OPTIC, RH READER

Opportunistic Tasks during vent and pump down work (see Betsy for coordination after July 29th:

ZnSe Window install(s) - would need to vent manifold section(s)
HAM8 in-vac cable troubleshooting
HAM2 SEI controls tune-up

In the afternoon we started placing components on HAM6 and HAM5 to measure the isolation ratio (green components in the attached).

The idea is to use the AUX laser we used for alignment, which will give us ~13mW through the SRM, and retroreflect the beam downstream of the OM1 so the return beam will be about 4mm in diameter at SRM (input beam is ~3mm in diameter, the IFO beam is ~4.4mm, so the return beam will be closer to the IFO beam in size).

Back-propagating return beam was located by inserting a HWP (not in the attached) between TFP and TGG, it's hitting the 50:50 cube and is going in the direction of point B in the first attachment. We blocked the forward propagating beam downstream and confirmed that the return beam went away.

The return beam is supposed to be colinear with the input beam but we haven't made any assessment of that. We will set up a temporary power meter holder at point B (haven't done that today). The HWP is still there in HAM5 but make sure to remove it when you measure the return beam power at point B.

The iris is roughly centered to the forward-propagating beam, but it's not very accurate. It's good enough to block the back-propagating rejected beam that is deflected away into -X direction.

50% of the input beam comes into the direction of point A, and we put a power meter holder there. You still have to adjust the height of the power meter but it's easy to see from the -X door using IR camera.

We misaligned SRM to see if we can locate the SRM reflection of back-propagating return beam in the direction of point A, but couldn't find any. We might try locating it again tomorrow.

The PCAL team (Tony S. & Cervane G.)  went down to End X today, Did an ES measurement. This End Station measurement analysis tool: 
python3 generate_measurement_data.py --WS "PS4" --date "2024-06-27" was before we even left the End Station.
This is almost ideal.
There was a little bit of git configuration to do as this was the first evocation of git on that particular laptop after that it worked.

There are a few notes that need to be added to the document though.
To run the Analysis code a date must be entered into to script. This date is the latest measurement date of the working standard you took with you to the End Station.
To find this date, one must go to

/ligo/gitcommon/Calibration/pcal/O4/lab/measurements/

git pull

gedit O4PSparams.yaml and search for PS4. the last date in the PS4 section will git you the date you need.

At a certain point I realized that it is easier to sign in to your own account or just use the following command to switch users within the terminal :

su 
Then answer the prompt for credentials.
From there I was able to very easily

git pull
git add 
git commit
and git push   all from the End Station.

The trend data was then ran from my laptop once I made it back to the Corner Station. This trend data still has the Latex embeded into the python code and will eventually be removed in next iterations.
https://git.ligo.org/Calibration/pcal/-/tree/master/O4/ES/measurements/LHO_EndX/tD20240730?ref_type=heads

Pictures of before and after beam spots look like this due to a beam movement done by Francisco.

TITLE: 07/30 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
SHIFT SUMMARY: This morning the fused silica piece for the OFI was installed, and afterwords the LVEA was transitioned to Laser HAZARD for alignment checks and to set up for an isolation measurement.
LOG:

Sheila, Keita, Jennie, Camilla

After practicing with the damaged Fused Silica (FS) wedge, Sheila and I installed the new FS wedge. Labeled E1900361 S/N 07 Run# P20-378, 379. We noticed some dust/fiber on the FS after install (didn't inspect before) so Keita wiped with a clean swab. Photo's after cleaning are first and second attachments.

Yesterday 79351 we found indium foil between part (3) and (5) of the FS assembly D2000037 where the (6) screw contacts. Rodica reccommended we add a new piece of indium foil. Third photo attached.

Keita installed the FS holder ot the assembly and we adjusted roll by eye. We installed the assembly onto the OFI. We reinstalled the beamdump bar (never moved dumps on it but wiped them yesterday) and the baffle bar and baffle. Baffle was installed in the same location, touching the double thick beamdump. We then unlocked the OFI and reinstalled the nominal motion limiter screws.

We then transitioned to laser hazard, the retroflection of the aux beam looked good and we checked that SRM was in it's nominal position. No reason to go to SR2.

The beam through the OFI started very (50mm?) low and was hitting the fast shutter. We then adjusted the roll of the FS wedge assembly to correct for any pitch,  it was hard to make fine adjustments and tightening the screw moved the beam. It was a little off in yaw. Keita has photos of the beam position.

We repeated yesterday's 79344 throughput power measurements with more laser power:

• Before OFI after SRM, 1) mean 9.627mW, stdev 198.1uW over 10sec 2) mean 9.862mW, stdev 289.6uW over 10sec 3) mean 9.901mW, stdev 287.8uW over 10sec
• SQZ beam power to ZM6: 1) mean 20.71uW stdev 367.3nW, Blocked/Background 200.1nW stdev 1.387nW, 2) mean 21.84uW stdev 481.9nW, Blocked/Background 251.1nW stdev 2.457nW, 3) mean 22.69uW stdev 548.6nW, Blocked/Background 228.9nW stdev 1.547nW,
• Input to HAM6 1) mean 11.10mW, stdev 306.4uW over 10sec 2) mean 11.10mW, stdev 268.0uW over 10sec 3) mean 11.50mW, stdev 270.3uW over 10sec
• Repeat before OFI after SRM @11:52PT (as laser power/polarization appears to be drifting), 1) mean 11.36mW, stdev 274.9uW over 10sec 2) mean 11.35mW, stdev 184.9uW over 10sec 3) mean 11.45mW, stdev 207.8uW over 10sec
• Repeat Input to HAM6 1) mean 11.49mW, stdev 255.6uW over 10sec 2) mean 11.46mW, stdev 217.1uW over 10sec 3) mean 11.55mW, stdev 195.4uW over 10sec
• Sheila will calculate the throughput and post in a comment.

The rejected beam to SQZ goes through ZM6 baffles, and around the middle of the HAM7 GV.

Sheila then headed to SR2 and checked that the beam was centered in pitch and yaw.

Dew point measurement taken this morning read at -43.8 ^oC.  Measurement taken before any activity inside chambers.  Soft covers were on HAM5 and HAM6, HAM7 is isolated and a bit pressurized.

Betsy, Camilla, Sheila, Jennie W, Keita, Robert

21:30 UTC Camilla and Betsy figuring out new way to lock diwn the OFI.

22:05 Placing peak sheet to shield ofi while they unscrew bars from FS assembly.

22:40 Took mount with bar and beam dumps still attached out of HAM5. One of the bolts for the bar was stuck in the mount so they unscrewed it chamber side.

22:42 Sheila dis-assembled FS wedge mount

Sheila left at 23:00 UTC

Camilla and Betsy taking photos and videos of damage and wiping beam dumps and mounts.

We found indium foil in the top screw hole of the mount which would sit on top of the wedge.

23:00 UTC Robert came to take photos between HAM5 and 4 from outside chamber.

23:14 Keita joined.

Lots of discussion about what to do about mounts as there was lots of the black coating in the screw holes and so Betsy and I washed the holes on the FS mount with isopropanol and she tapped the holes again.

00:10 Camilla and I put beam dumps back onto OFI.

Mount and old FS wedge covered up chamberside and cover back on.

Everyone out by 00:15 UTC.

Camilla to add pics.

Noticed that GV5 had hard closed on Saturday at 19:59 utc time, no human intervention.  It appears as if the instrument air pressure left for soft close GV5 was enough to hard close it.  According to PEM instruments near GV5 made lots of noise, see attached plot, accelerometer and microphone data.

I checked the dial on the gauge to measure the instrument air at GV5, and indeed there was only about 10 psi, this value is within the "usual" pressure used for soft clossing pneumatic gate valves and per procedure.

No interaction is required at this moment from the vacuum team.

Tagging ISC, since sensitive equipment is hanging near this gate valve, like cameras and OpLevs.

Keita, Sheila

Summary:  We chipped the spare KTP crystal this morning, and this afternoon installed the back up spare that Rodica had shipped.  We've adjusted the roll, and the pitch angle seems better than the crystal that we removed.  So this should be ready to go into the chamber first thing Monday morning.  We have many photos from today, which will be attached and annotated to this alog later. 

Following on From Jason's alog 79319

With this placement of the damaged KTP in it's assembly, where the assembly is bolted perpendictular to the beam path, and a wave plate to mix the polarizatoins upstream of the KTP,  we have 13.5mW in the p polarized beam (see first attachment which is a diagram Paul sent us this morning), 16.3mW in the s polarized beam, and 2.3 mW in the AR surface.  This is not set up with the AOI that the AR coating is designed for, which is why the AR beam is large, we can take advantage of this to set the pitch by setting the AR reflection parallel to the table.. 

With the original KTP in place, the AR reflection isn't parallel to the table it is pitched up by 10/(530 +405 mm) about 11 mrad. The optic lab beam is hitting the KTP a little below the burned spot, which would have been on the +X side in chamber.  The burned spots are on the side closer to our alignment laser.

Before taking it out of the mount we took a variety of photos showing the damage spots position.  We did not find any indium foil in the mount, Paul had warned us that there might be indium between part 5 and part 9 of D2000038. 

As we were placing the new crystal in the mount, we left the set screws (11) that hold the peek loose, and held the piece upsidedown while we screwed in the bolts labeled #10 to hold on the aliuminum plate.  It chipped as we were tightening the bolts labeled 10 in D2000038. After some discussion with Rodica, Paul, Gabriele, we went back to the lab to take photos of the chip and try to understand how the chip happened.  We have photos showing that the crystal was proud of the top of part 5, the orientation of the black metal piece.  After we removed the black front plate, we could see that the KTP was firmly stuck in part #5, with the wedge stuck.  Keita had to push on the back of the crystal to get it loose. 

Keita made a series of measurements using calibers:

Chipped KTP: (agrees well with the drawing: E1900284)

• height on thicker side: 0.8850 inches
• heght on thinner side: 0.8845 inches
• width (center to center): 0.8870 inches
• width from one corner to the other (longest width): 0.9360 inches
• thickness: 0.5055 for thicker side

part 5: https://dcc.ligo.org/DocDB/0171/D2000567/001/D2000567_A%2B_OFI_KTP_Wedge_Holder.pdf

• side to side width of the opening for the crystal (measured on the side where the black part attaches) 0.9225 inches
• depth of the slot 0.515 inches on the deeper side.
• depth of the slot 0.458 on the thinner side
• height of the slot, including space for peek, 1.003 inches

peek:

• thickest part 0.1105 inches
• thinnest part: 0.1095 inches

total height (max): crystal + peek = 0.885+0.1105 = 0.9955 inches, smaller than 0.2mm than the height of the slot.

cratered KTP:

• height of crystal at thick side 0.8855 inches
• height of crystal at thinner side: 0.8835 inches
• width (center to center): 0.887 inches
• width diagonal: 0.9345 inches
• thickness of thicker side: 0.5095 inches

We then did a trial run (using the chipped KTP) of an approach that we think avoids the problem of letting the KTP get wedged in the holder.  We set the KTP on several wipes on the bench, and set the peek underneath it.  We then slid the holder (part #5) over this whole thing, which went smoothly, and tightened the set screws.  After flipping it over, we can see that the KTP is not proud of part #5, and it sits nearly flush to the front of the holder.  We could then easily attach the black front plate.  We decided to do this with the final spare, which had 2 small chips on the edge. 

With that spare installed in the assembly, we adjusted roll using the alignment laser that Camilla and Jason set up.  We wanted to adjust roll so that the transmitted beams were level to the table, since we know that the laser bea we started with were parallel to the table.  The roll adjustment was sticky, and tightneing the set screw tended to lower the transmitted beams.  The beams transmitted are off in yaw compared to the ones from the cratered KTP, by about 7mm/870mm + about 8 mrad.  We had difficulty seeing the AR reflected beam, but we can see a tiny beam with all the lights off (this suggest that the reason the beam was so bright before was the coating damage, not the AOI of the crystal in our set up.). At 820 mm from the KTP, the AR beam was about 1 mm too low, so it's pitched down by 1mrad. 

We think this is about as good as we can do by adjusting with this mount, so we are satisfied and will leave the KTP assembly under wipes and foil to be reinstalled on Monday.