Rick and I went to EndY to do the PCAL Tx module maintanence today.
We followed Mostly followed the procedure outlined in DCC doc T1600436-v11 which was printed out and attached to the ALOG.
I have also updated the PCALTxMaintenanceLogBook spreadsheet with the latest information from today's activity. This is information is now in the DCC with an updated version number.
Attached a picture of the OLTF taken with the SR785 .
And a beam spot with both beams after we were finished cleaning and measuring.

[Rahul Betsy Keita Ali Koji]

The extraction of the old OMC (Unit #3) and installation of the new OMC (Unit #1) went exceptionally well.

= OMC Extraction =

Tuesday morning, we resumed HAM6 work from the OMC extraction.
Rahul and Koji went into the chamber. Rahul positioned close to HAM5, and Koji was on the other side.
They followed the extraction procedure (E1600164) after some rehearsals.

• Unhooked the wire clamps on Rahul's side.
• Unhooked the wire clamps on Koji's side.
• Lifted the OMC from both sides and extracted it to Koji's side.

During the OMC extraction, assistance from two others was very effective in supporting wires from both HAM6 openings, preventing the wires from touching the OMC. (The procedure to be updated)
The extracted OMC was placed in the fixture on the ISI and moved back to the work table for further action.

= Balance Mass Migration =

Balancing masses were transferred from the previous OMC to the new one (Attachment 1). At the same time, a Viton ring and a 10g mass were added to each corner for the body mode damping (See T1700471).
The mass distribution differed from what Koji had figured out from the past unclear photos. But the masses could be fixed to the OMC using various 1/4-20 screws that were prepared for this.
Only light torque was applied to the fixing screws to avoid delamination/fracture of the mounting brackets below the mass mount.

= Final OMC cleaning =

All the optical surfaces were cleaned by FirstContact except for a couple of surfaces where the access was quite limited. (Attachment 2)

We let the FC paint dry during lunch and then resumed peeling them off, combined with discharging with Top Gun.
The surfaces were checked with a flashlight to find any residual.
A FC residual was located not on the optical surface but on the corner of a tombstone prism. It was cleaned with additional FC paint.

In parallel with the cleaning work, Ali and Keita worked on the review of DCPD-related cable shielding in HAM6.

= OMC Installation =

The reverse process of the extraction has been performed.

• Brought the OMC in the OMCS frame
• Hooked the wire clamps on Rahul's side.
• Hooked the wire clamps on Koji's side.

When inserting the clamps into the clamp hooks, sometimes incomplete mating happens due to friction between the copper cone and the frosted glass cup.
This can be fixed by pushing the clamp into the slit by a small flat-head driver, while the tension on the wire was released by lifting that side of the OMC.

= EQ stop release =

Reverse process of the OMCS mass clamping.

• OMC EQ stops were released:
  We noticed a corner of the OMC on the HAM5 side was bottoming on an EQ stop.
  We decided to lower the EQ stop by releasing the fixing screws for the EQ stop holder. The holder was tilted, and the OMC became free.
• IM blade stops (Qty 4) released
• IM EQ stops 1/4-20 hex nuts (Qty 2) released
• IM EQ stops (Qty 12) released
• Top blade stops (Qty 2) released

This made the OMC free. Rahul quickly checked the transfer functions of the OMCS as well as the damping control.

We decided to stop here. (Attachment 3)

Next Steps:

• Beam alignment
• Possible suspension alignment
• Check electrical connections
• Reinstall the OMC shroud panels

[Julian, Naoki, Camilla, Sheila, Vicky]

Summary to get SQZ alignment beam: Launched 76mW into seed fiber, ~25 mW incident on opo cavity, ~0.85 mW transmitted through opo cavity. Had to find opo transmission past the VIP, for this we used green SK path as a reference. This ~0.85 mW opo transmission was bright on an IR card at the HAM5 gate valve, and enough to iris the SQZ beam in HAM7 and HAM6 (for OMC work 75512). DC 3/4 centering loops engaged easily, then OMC A/B QPD's saw the sqz beam.

----------- Notes from today ------------------------------------------

Launched power into SEED fiber (SQZT0): 76 mW

OPO IR REFL (CLF_TRIG_REFL_DC_POWERMON @ SQZT7): 24.8mW   (when opo is dither-locked).

Fiber rejected power PD in HAM7 (CLF_REFL_REJ) is 5.3 mW.
  -->  Seed fiber coupling: ~34% of the seed fiber launched power was incident on the opo cavity. 
  -->  40% coupling through fiber, ~6% mispolarized and rejected after fiber. This is similar to recent fiber alignment 75344, even after more recent on-table work 75486.

We had to find the OPO IR transmitted beam after the VIP. Nothing at first despite restoring suspensions 75502. Notes to self on what worked to find the SQZ beam post-vent:

• Started with no opo trans after the VIP, despite checking SQZT7 periscopes and the HAM7 RLF QPD's (which we use for FC WFS).
• 75502 saw ZMs had shifted after vent. Naoki 1) offloaded all FC+SQZ ASC and set all PSAMS offsets back to "nominal", then 2) he and Austin restored ZM1-6 + FC1 slider values to the same P/Y damp values as we last had in observe. Still did not see beam past the VIP (nothing on RLF QPD's, nothing on SQZT7 IR camera).
• SK path was helpful to find the VIP transmitted beam.
• Looking at the bottom SK periscope mirror on SQZT7 like here, we walked FC1 P/Y sliders to overlap FC_GR_REFL (which sees FC REFL), with OPO_REFL (which does not see FC REFL, and thus is a good alignment reference for the FC REFL path including ZM1-2-3-FC1).
• Used FC1 P/Y sliders to overlap FC_GR_REFL with OPO_REFL (looking at an IR card on the periscope lower mirror). While doing this, we found OPO IR TRANS on the RLF QPD's.
• Then we walked FC1 and ZM3 to maximize transmitted power, ie OPO_IR_DC_POWERMON. Not totally optimized, but seemed reasonable to keep going.

OPO IR TRANS (OPO_IR_PD_DC_POWERMON @ SQZT7): 0.85 mW  -- Just before opening the HAM7/5 gate valves. Opened the beam diverter, SQZ beam was bright on an IR card held at the HAM5 gate valve.

After opening gate valve, immediately saw the beam on AS A/B/C QPDs.

ASC-AS_A/B_DC_SUM_OUTPUT ~ 60.  ASC-AS_C_NSUM_OUT16 ~ 0.65-0.67.  

HAM6 crew irising SQZ beam, 75512.

HAM7 crew irising SQZ beam. Julian has some photos of HAM6 and HAM7 irses. Sheila -- looks like there is some clipping on the VIP (we have not totally optimized FC_REFL path slider alignments post-vent, just found the beam). Revisit this FC REFL alignment later.

Engaged DC 3/4 centering. It just worked. Control signals near 0. 

We see the beam on the OMC QPD's, power is consistent with ASC-AS_C power, around 300-400e-6 on each OMC QPD A/B. Power goes away when SQZ beam diverter is closed. See omc powers screenshot with as_wfs powers.

TO-DO SQZ work later:

• more photos of HAM7 irises
• measure sqz beam powers with power meter
• undo VIP clipping (using e.g. FC1/ZM3) - we didn't fully optimize this FC REFL alignment yet after venting.

Today's activities:
- The RGA tree at EX was leak-checked, and multiple flanges were leaky, possibly because of some overheating during a bakeout in the past. The gaskets will be redone, and the all-metal angle valve will be also replaced
- EX was vented
- The VPW vacuum chamber was opened, after the 2 stuck screw was removed
- Both 2 spare roughing stations are entirely finished
- All the Hepta header filter works were finished in the LVEA

TITLE: 01/23 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

• Today focused on OMC work with LVEA switching to laser SAFE for the day.
• EX vented for baffle work tomorrow.  
• EY is Laser HAZARD for PCAL work (and transitioned back to SAFE afterward).
• LVEA back to HAZARD

LOG:

• 1545-1642 LVEA cleaning & HAM6 all clean (karen.kim)
  • 1715-1818 EX maintenance cleaning (kim)
  • 1738-1921 EY.MY maintenance cleaning (karen)
  • 1838-1953 More LVEA cleaning (kim)
• 1600 Snow removal for Y-arm/EY (randy)
• 1608 FAMIS checks in LVEA and then down Yarm and then Xarm (Chris)
• 1612 Fire alarm contractor arrives for Tyler
• 1622-1641 Transitioning LVEA to Laser (Upgrade) SAFE! (tj)
  • Also moved a dust monitor near HAM3 (tj)
• 1632-1647 Parts check in East Bay (jordan)
• 1655-1709 TCS Chiller checks/fill (corey)
• 1701 OMC swap @HAM6 (keita, betsy, rahul, koji)
  • 1748-1807 High dust counts noticed, TJ heading out to check.  (Mentioned counts were low/normal when he came back.)
  • Lunch break around 1945
• 1723-1741 Dew point measurements in lvea (gerardo)
• 1723-1729 Grabbing parts in LVEA (jordan)
• 1727-2330 Prep for EX baffle work (robert)
  • Needs to wait until VAC team is done venting
• 1741-1956 RGA work at EX (gerardo, jordan)
  • 1956 lunch break
• 1745-1917 Slow controls upgrade + DAQ restart (daniel, dave)
• 1754-1935 LN2 delivery for MX (norco)
• 1812 VAC work while laser SAFE (janos)
• 1817-1848 Squeezer slow controls power supply swap (marc)
• 1827-1845 Grabbing part from Filter Cavity Tube Enclosure (travis)
• 1842-1901 LVEA walkthru (richard)
• 1845-1911 Looking at removed OMC (tj, oli, austin, ryanC)
  • 1916-1932 Another look (ryanS,vicky, naoki)
• 1907-2011 FARO work (jason, ryanC)
• 1925-2252 EX lights (ken)
• 1928-1946 LVEA recon (travis)
• 1943/afternoon:  Moving equipment to EY for Wind Fence (randy)
• 2007-2012 Checking on patch panels at CER (jonathan)
• 2010 PCal Maintenance at EX & EY (tony, rick)
• 2040-2254 Baffle assy work in lvea (mitch)
• 2103-2327 Optics Lab and then off to SQZT7 (vicky, daniel, naoki)
• 2103-2303 HAM6 OMC team return (rahul, koji, keita, betsy, Ali)
• 2112-2146 Disabling high Voltage at EX (fil)
  • Confirmed EX Picomotor 
• 2114-2344 FARO work (jason, ryanC, tyler)
• 2128-2300 TCS Laser swap prep (tj, camilla)
• 2129-2300 Checking out electronics for accelerometer for making a work permit (marc.jamari)
• 2152 Venting EX (travis.janos.gerardo.jordan)
  • Took EX ISI to:  ISI_DAMPED_HEPI_OFFLINE 
• 2245 EY to laser HAZARD (tony)
• 2303-2348 Rahul running OMC SUS rubbing measurements
• 2345-2350 Transitioning LVEA back to HAZARD (camilla)
• 2345-0000 Searching for vacuum cleaner in lvea (tj)
• 2347 Restoring purge air (Betsy)
• 2351 Turning on the Squeezer laser (camilla)
• 2354 SQZT0 & maybe SQZT7 work  (vicky, daniel, naoki) 

WP 11645
Procedure M1300464

The following high voltage power supplies/electronics were powered off in preparation for the EX vent.

1. EX ESD HV and Low Voltage Chassis
2. EX Ring Heater

F. Clara, G. Moreno

Late entry. Activities on Jan 22nd:
- The HAM7 X+ and X- doors have been removed
- The purge air was switched on at EX
- GV20 (at EX) was closed - the GV struggled with closing, but in the end it seems to be OK
- Electrically 1, mechanically both 2 spare roughing stations are finished
- VPW C+B door issue - 2 screws stuck, tomorrow will open it: this load has some blanks and new Hepta headers, which will be also needed

At 10:33 the DAQ 0-leg was restarted, followed at 10:38 by the 1-leg. The DAQ restart was for two EDC changes: Daniel's new slow controls CS_SQZ channels and Patrick's additional FMCS channels.

The EDC was restarted at 10:33.

A new SQZ SDF monitor.req file was installed the and h1syscssqzsdf service was restarted.

Tue Jan 23 10:06:58 2024 INFO: Fill completed in 6min 54secs

Gerardo confirmed a good fill curbside.

Addressed TCS Chillers (Tues [Jan23] 855-910pm local) & CLOSED FAMIS #26166:

• TCSx Chiller:  Had level of 29.4 cm.  Added 310mL for 30.2cm.
• TCSy Chiller:  Had level of 9.8 cm.  Added 85mL for 10.0cm.
• There was no water in the small cup under the slow leak.

TITLE: 01/23 Day Shift: 16:00-00:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: EARTHQUAKE
    Wind: 6mph Gusts, 3mph 5min avg
    Primary useism: 0.22 μm/s
    Secondary useism: 0.15 μm/s
QUICK SUMMARY:

• LVEA transitions to SAFE today!!
• HAM7 SQZ work continues today.
• HAM6 OMC swap continues with extraction next.
• About 90min ago we had a 6.3M EQ from Vanuatu area.

Workstations were updated and rebooted.  This was an OS package update.  Conda packages were not updated.

[Rahul, Keita, Betsy, Koji]

Preparation work to extract the existing OMC has been completed. We will continue with the OMC extraction tomorrow morning.
The overall work procedure for the OMC replacement is summarized in G231106 https://dcc.ligo.org/LIGO-G231106.

= OMC shroud panel removal =

While waiting for the beam from the squeezer to come, we started the removal of the OMC shroud panel in parallel. The work was done along with the procedure E1600164.
The removed panels were placed on a stainless steel table in the HEPA booth of HAM6 (Attachment 1). The panels were not covered to prevent accidental placement of objects on them.

During the work, a beam dump was removed from the table to make the removal work possible. This beam dump is to kill one of the weak transmissions of the OMC.
Betsy took the photo record of the location, but it is safely trivial how it should be aligned.

= SQZ beam marking and alignment =

The beam was delivered to HAM6 and was pinned down with two irises on the ISI table.
The irises were placed just after the beam entered HAM6 (next to OM2) and just before OM1 (next to the fast shutter).
This means that these indicators are not affected by the alignment in HAM6.
They were placed by eyeballing, so their precision was as such. By default, both the irises were set to the maximum opening.

Next, the beam alignment was servoed towards the WFS heads using the DC centering ASC loops.
As soon as the control was applied, both QPDA and QPDB of OMC showed significant signals with total light level of ~1e-3 (Attachment 2).
When the light was blocked (at the squeezer?), the value dropped to almost zero, confirming that this was a real beam.
This is very good news as we'll be able to find the beam arrival using the OMC QPDs when we try to align the new OMC.

= Holding suspension mass =

Next, we proceeded to hold the suspension masses. Rahul and Koji worked in the chamber on the ISI table for the following operations.

To hold the intermediate mass:

• First, the top blade was fixed with stopper screws.
• Next, we tried to fix the middle mass with two 1/4-20 nuts, but this caused some wobbling of the suspension. So, we first decided to fix the middle mass with smaller side EQ-stops. This process has not been described in E1600164. (to be updated)
• Once the middle mass was fixed horizontally, the vertical dof was also fixed firmly with the small EQ-stops and the 1/4-20 hex nuts.

Then, moved onto fixing the OMC:

• The bottom EQ stop for the OMC was left as they could not touch the OMC. The side (long side) EQ stops were extended and are holding the OMC horizontally.
• The Top EQ stops for the OMC were removed by removing the L-shaped brackets on both sides.

= Removing the electronic cables from the OMC =

Upon removing the electronics cables, one person held the cable harness on the OMC breadboard to prevent the OMC from wobbling too much.
The removed cables were wrapped around the top part of the suspension frame to keep them out of the way of the further work.

At this point, it was just at 5pm, so we exited from the chamber.

Next Steps:

• Extraction of the OMC
• Migration of the balance masses to the new OMC
• Final cleaning of the new OMC
• New OMC installation

WP 11635
WP 11637

The following high voltage power supplies were powered on this morning:

1. HAM7 - PZT and P-Sams
2. HAM6 - PZT and Fast Shutter

The pressure interlock system bypassed.

Ibrahim, TJ, Camilla, Naoki,

Looking at how the ZM4,5,6 alignment has shifted both with the vent and recent temperature changes in the LVEA.

Attached is ZM4/5 P/Y alignment since the last time we were SQZing to vented now,  there is large changes of ZM5 (470urad in Pit and 230urad in Yaw). Alignment sliders haven't changed but SQZ ASC would have been changing some alignment when the IFO was locked.

ZM6 has large changes (1300urad in Pit and 280urad in Yaw). Currently DAMPED but alignment sliders are the same. Edit: DAMPED turns off the alignment sliders, once Austin brought back to ALIGNED it had moved <100urad.

We expect some changes from bouyancy of air. The HAM7 SUS are currently  "aligned" with the doors being taken off HAM7. Jim hasn't locked the ISI yet. Looking at ZM4,5,6 alignment, last vent, IFO locked, and now.

Ibrahim is looking at temperatures and alignment since our last vent.

Vicky Daniel

Today we swapped the beamsplitter in the squeezer laser path that transmits a sample beam to the IR PD (which monitors the laser power). The old splitter was 98:2 for p-polarization and transmitted about 0.1% in s-polarization. We replaced it with a 98:2 meant for s-polarization that transmitted just shy of 1%. After a turning mirror, another 50:50 splitter was installed. The transmitted beam is used for the IR PD, whereas the reflected beam passes through a half wave plate, a polarizing beam splitter, a quarter and a half waveplate, and two additional turning mirrors into a fiber coupler. The other end of the fiber was connected to the squeezer laser input of the fiber beat note box. We also moved the fiber PSL sample beam from the table feedthrough to the PSL input of the fiber beat note box. This allowed us to lock the TTFSS with the new setup.

A slight realignment was required for the CLF, seed and SHG paths. The power coupled into these fibers came back to near the values where they were.

The channels H1:SQZ-FIBR_TRANS_DC and H1:SQZ_FIBR_REJECTED_DC are now monitoring the power in the fibers of the PSL and squeezer lasers, respectively.

The squeezer laser has been turned off and locked out again after the work was finished.

Camilla, Naoki, Sheila, Nutsinee

We did a repeat of the measurement set from 73621 with OM2 cold.  For a summary, Camilla's plot shows 200V/200V PSAMs setting with solid lines and 120V/120V as dashed lines. There is a stronger frequency dependence for the 120V/120V settings, which confirms what we saw with OM2 hot, that 200V/200V has better mode matching and less frequency dependent SQZ rotation. (This plot is a direct comparison to October's data. )

The third attachment is a plot that shows that the squeezing angle that maximizes the squeezing at 2kHz is not the same as the one that maximizes the squeezing at 200Hz, (green traces are optimized for 2kHz, blue traces are optimized for 200Hz, solid is 200V/200V and dashed is 120V/120V), you can see that the frequency dependence is larger for 120V/120V.

The fith attachment compares OM2 hot vs OM2 cold for antisqueeze and squeezing, with PSAMS at 200V/200V.  There is less anti-squeezing with OM2 hot, which could be due to a difference in nonlinear gain or reduced readout losses.  The green traces show that the squeezing level is similar, although the no sqz spectra is also different between the two times. 

times:

• NO SQZ: 2023/12/20 18:00:16- 18:20:40 UTC  (during this time we reset AS42 offsets see attached, and measured NLG 18.1) ref0
• SQZ: PSAMS 200/200 CLF RF6 203.85 deg 18:24:30- 18:31:33 (ASC running) ref19
• ASQZ:PSAMS 200/200 CLF RF6 270.22 deg 18:35:00-18:40:00 (ASC IFO and FC off) ref20
• MID SQZ+: PSAMS200/200 CLF RF6 237.04 deg 18:42:00-18:47:10 ref 21
• MID SQZ-: PSAMS 200/200 CLF RF 89.13 deg 18:50:40-18:56:00 ref 22
• repeat sqz slightly better at low F worse at high F: PSAMS 200/200 CLF RF6 194.37 deg 19:00:30-19:07:20 ref 23 (a couple of glitches happened)  (suggests we should be watching 100Hz to tune SQZ ANG instead of 1kHz)
• turned ASC back on, moved PSAMS to 120/120, waited about 3 minutes for the AS42 to converge. 
• SQZ PSAMs 120/120 CLF RF6 214.28 deg 19:18:30-19:24:00 ref 24(This is the DEMOD angle that gave the best sqz at 2kHz, changing the PSAMs changes which demod angle this best squeezing is at)
• SQZ PSAMs 120/120 CLF RF6 194.37 deg 19:27:40-19:33:20 ref 25  (better SQZ at 200Hz)
• ASQZ PSAMS 120/120 CLF RF6 100.5 deg CLF servo sign flipped 19:42:20-19:47:40 ref 26
• MID SQZ PSAMS 120/120 CLF RF6 237.04 deg 19:49:10- 19-54:50 ref 27
• MID SQZ PSAMS 120/120 CLF RF6 89.13 deg 19:56:10 - 20:01:40 ref 28

Since our ASQZ with PSAMS 200/200 was a little lower than with 120/120, and that seemed inconsistent with our sqz data and our previous measurement with OM2 hot, we went back to SQZ with PSAMS 200/200, ran ASC then turned it off, and checked the sqz angle carefully. This did give a little more anti-sqz to replace the reference 20 above:

• ASQZ PSAMS 200/200 CLF RF6 100.5 deg CLF servo flipped 20:13:15- 20:19:30 ref 29

Camilla saved these references in userapps/sqz/Templates/dtt/DARM/PSAMS_tests_Dec2023.xml