TITLE: 08/01 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Corrective Maintenance
INCOMING OPERATOR: None
SHIFT SUMMARY: Today's work was mostly lots of final checks/cleaning before we can close the enclosures. Doors are not on, but HAM6 TFs show that we are good to go(SUS, SEI), and we are having problems with one of the OSEMs on SRM M1 on HAM5, so we'll be looking at that more tomorrow.
LOG:

Tony, Fil, Erik, Jonathan, Dave:

On the outside of the north-east corner of the LVEA PSL enclosure there is a wall display computer which shows the enclosure camera images.

Today we replaced this aging mac-mini computer with an Intel NUC configured as a FOM machine.

The new machine is called lveapslfom. It is currently configured to show the same camera images as the PSL FOM in the control room.

The computer's display is snapshotted and can be viewed on the CDS web server

lveapslfom-1.png

I took the SR3 transfer functions this afternoon. I took SUS_SR3 to damped then reengaged the test filter outputs and set gains to 1, and turned off the damping filter outputs and set the M1 coil driver state from 2 to 1.

While taking the V TF Rahul and I noticed the shapes looked weird, from this we noticed that the T1 analog dewhitening coil driver wasn't switching on and off which led to the investigations in alog79419.

Data lives here 
    /ligo/svncommon/SusSVN/sus/trunk/HLTS/H1/SR3/SAGM1/Data/
        2024-08-01_2000_H1SUSZM6_M1_WhiteNoise_L_0p02to50Hz.xml
        2024-08-01_2000_H1SUSZM6_M1_WhiteNoise_P_0p02to50Hz.xml
        2024-08-01_2000_H1SUSZM6_M1_WhiteNoise_Y_0p02to50Hz.xml
        2024-08-01_2000_H1SUSZM6_M1_WhiteNoise_T_0p02to50Hz.xml
        2024-08-01_2000_H1SUSZM6_M1_WhiteNoise_R_0p02to50Hz.xml
        2024-08-01_2000_H1SUSZM6_M1_WhiteNoise_V_0p02to50Hz.xml

Plots:
    - all DOFs to all DOFs compared against the model for this measurement (2024-08-01_2000_H1SUSSR3_M1_ALL_TFs.pdf), and then
    - a comparison between this measurement and the 2 most recently available known-good measurement (2024-08-01_H1SUSSR3_M1_Phase4b_unDamped_ALL_ZOOMED_TFs.pdf).

After my discovery in this alog that the phase and gain margins were pretty tight on HAM2, I did a bunch of olg measurements on HAM2&3 and tweaked the loop gains and boost filters to reduce the gain peaking around 40 hz. More or less all DOFs on these chambers had ugfs around 35hz and phase margins around 5 degrees. Kinda suprised this was stable, I haven't looked at these in a long time. I do wonder if something is funky with the measurement, but I don't know what that would be. Attached image shows one of the worst, the Z dof on HAM3. Blue and yellow are the new loops gain and sensitivity, red and purple are the old loop. The filter changes might make things slightly worse in the 10-20 hz region, but that should be somewhat compensated by the HEPI to ISI feedforward. Should improve the  30-40 hz motion somewhat though.

J. Kissel

Executive Summary: Took SUS ZM6 (a HAM "Simple" Double Suspension, or HSDS) health-check transfer functions. Looks good. H1SUSZM6 is GO FOR DOORS

Here're the results of pre-doors health check of the suspended dynamics and OSEM electronics of H1 SUS ZM6 after the vent to repair the OFI. 
ZM6 wasn't mechanically touched at all during the vent, so we expect everything to be just as excellent as before, and this is indeed the case.

Attached are the usual plot collections showing 
    - all DOFs to all DOFs compared against the model for this measurement (2024-08-01_1937_H1SUSZM6_M1_ALL_TFs.pdf), and then 
    - a comparison between this measurement and most recently available known-good measurement (allhxdss_2024-08-01_H1SUSZM6_Phase3a_PreDoorsCloseout_ALL_ZOOMED_TFs.pdf).

HAM5 ISI was floating and damped with HEPI locked.
Coil Driver configuration requested to be in State 2, to correctly compensate the analog HAM-A driver that's permanently jumpered to have its low pass ON.
No alignment offsets were on during the measurement.

Data lives here 
    /ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/ZM6/SAGM1/Data/
        2024-08-01_1937_H1SUSZM6_M1_WhiteNoise_L_0p02to50Hz.xml
        2024-08-01_1937_H1SUSZM6_M1_WhiteNoise_P_0p02to50Hz.xml
        2024-08-01_1937_H1SUSZM6_M1_WhiteNoise_Y_0p02to50Hz.xml

Comparison script -- svn up'd prior to changes, and then with this data added -- has been committed to
    /ligo/svncommon/SusSVN/sus/trunk/HXDS/Common/MatlabTools/
        plotallhxds_tfs_M1.m     rev 11913

Fil, RyanC, Rahul

We have replaced the triple top coil driver for SUS SR3 after finding  binary issues with T1 channel on the M1 stage - see pic attached. T1 LP filter was not switching OFF and was stuck at ON. We looked at the SUS HAM5-6 system wiring diagram on D1002740 and found out that the chassis is at slot41, Rack C7. At first Fil tried re-setting the chassis (binary chasiss was power cycled) and then replaced cable no 44 and 45 (page 1 0f D1002740), which didn't give us the desired results, i.e T1 was still stuck at On, while channel LF and RT (Test/COIL) turned Red at the AI chassis.

Fil then decided to replace the Top Triple coil drive and this fixed the issue. Given below are the s/n of the old and new coil driver,

New - S1001082

Old - S1100192

I have added the above information on the e-traveler.

J. Kissel

Executive Summary: Took SUS OFI health-check transfer functions. Looks good. H1SUSOFI is GO FOR DOORS.

Here're the results of pre-doors health check of the suspended dynamics and OSEM electronics after we've swapped the KTP crystal (LHO:79344) and Fused-Silica Wedge (LHO:79363) to repair the OFI. Note, this is also after the SD OSEM was pulled and replaced (see LHO:79387). 

Attached are 
    - the individually processed full DOF to DOF plots -- 2024-08-01_1741_H1SUSOFI_M1_ALL_TFs.pdf
    - the comparison between the most-recent pre-vent data from LHO:79198 -- allofiss_2024-08-01_H1SUSOFI_Phase3a_PreDoorsCloseout_ALL_ZOOMED_TFs.pdf

The OFI suspension and electronics look healthy, with a similar frequency response to the 2024-07-17 data with the expected lower coherence that one gets in air with purge running. 

ISI was floating and damped during this measurement. Digital request of coil driver state was 2, matching the analog electronics (a HAM-A driver) that has been jumpered with the low pass filter ON. No alignment offsets were on during the measurement.

Data lives here:
    /ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data/
        2024-08-01_1741_H1SUSOFI_M1_WhiteNoise_L_0p02to50Hz.xml
        2024-08-01_1741_H1SUSOFI_M1_WhiteNoise_T_0p02to50Hz.xml
        2024-08-01_1741_H1SUSOFI_M1_WhiteNoise_Y_0p02to50Hz.xml

Data comparison script with this data added to it has been updated and committed to
/ligo/svncommon/SusSVN/sus/trunk/OFIS/Common/MatlabTools/
    plotallofis_tfs_M1.m  [rev 11909]

SUS HAM 5-6 System Wiring Diagrams D1002740
Grounding and Shielding at LIGO T1200131

Things to note:

1. HAM6 ISC cabling was not checked for ground loops
2. Short found on the OFI (cable SUS_SQ_30). Pin 13 shorting to ground. In-chamber ground NOT resolved.
3. All cables listed below passed testing:

SUS_HAM5_001 (SR3 Top)
SUS_HAM5_002 (SRM/SR3 Shared)
SUS_HAM5_019 (SR3 Middle)
SUS_HAM5_020 (SR3 Bottom)
SUS_HAM5_003 (SRM Top)
SUS_HAM5_025 (SRM Middle)
SUS_HAM5_026 (SRM Bottom)
SUS_ZM6_21 (ZM6)
SUS_HAM6_10 (OMC Top/Left)
SUS_HAM6_11 (OMC Right/Side)
ISC_236 (OM1)
ISC_237 (OM2)
ISC_238 (OM3)

After OFI shroud was put back on Mitch and I unlocked HAM5 ISI. Shifts from the range of reference position were all less than 7urad. Looking at trends CPS RX and RY locations changed up to 15 urad while the OFI work was being done and the table was locked. I will change the reference postion to be in the middle of that range, but should be very close to where the table is hanging now.

This morning I took transfer function measurements on all of the suspensions in HAM6 chamber and they look healthy.

The templates are given below,

/ligo/svncommon/SusSVN/sus/trunk/OMCS/H1/OMC/SAGM1/Data

2024-08-01_1900_H1SUSOMC_M1_WhiteNoise_L_0p02to50Hz.xml
2024-08-01_1900_H1SUSOMC_M1_WhiteNoise_P_0p02to50Hz.xml
2024-08-01_1900_H1SUSOMC_M1_WhiteNoise_R_0p02to50Hz.xml
2024-08-01_1900_H1SUSOMC_M1_WhiteNoise_T_0p02to50Hz.xml
2024-08-01_1900_H1SUSOMC_M1_WhiteNoise_V_0p02to50Hz.xml
2024-08-01_1900_H1SUSOMC_M1_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/OM1/SAGM1/Data

2024-08-01_1900_H1SUSOM1_M1_WhiteNoise_L_0p02to50Hz.xml
2024-08-01_1900_H1SUSOM1_M1_WhiteNoise_P_0p02to50Hz.xml
2024-08-01_1900_H1SUSOM1_M1_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/HXDS/H1/OM2/SAGM1/Data

2024-08-01_1600_H1SUSOM2_M1_WhiteNoise_L_0p02to50Hz.xml
2024-08-01_1600_H1SUSOM2_M1_WhiteNoise_P_0p02to50Hz.xml
2024-08-01_1600_H1SUSOM2_M1_WhiteNoise_Y_0p02to50Hz.xml

/ligo/svncommon/SusSVN/sus/trunk/HTTS/H1/OM3/SAGM1/Data

2024-08-01_1630_H1SUSOM3_M1_WhiteNoise_L_0p02to50Hz.xml
2024-08-01_1630_H1SUSOM3_M1_WhiteNoise_P_0p02to50Hz.xml
2024-08-01_1630_H1SUSOM3_M1_WhiteNoise_Y_0p02to50Hz.xml

The postprocessing of the data is still ongoing and the plots will be posted soon.

Dew point measurement taken this morning read at -43.6 ^oC.  Measurement taken before any activity inside chambers.  Soft covers were on HAM5 and HAM6, HAM7 is isolated.

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.

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.

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.

J. Kissel
 
Executive Summary: In prep for the upcoming vent, I've measured the undamped dynamical transfer functions of the H1SUSOFI. The dynamics look healthy.

The rest of the story: The OFI's digital control system has had a sordid history (mostly the OSEM2EUL and EUL2OSEM matrices, but also the damping loops), and assessment of it's health has been person power limited over the years. I've fixed all that today, and restored the suspension's control system to good health -- such that the transfer functions match the model as they did (once) in 2023. More details explaining the plots later, but we're good to go for the vent. 

Today's data lives here
    /ligo/svncommon/SusSVN/sus/trunk/OFIS/H1/OFI/SAGM1/Data
        2024-07-17_1741_H1SUSOFI_M1_WhiteNoise_L_0p02to50Hz.xml % undamped
        2024-07-17_1741_H1SUSOFI_M1_WhiteNoise_T_0p02to50Hz.xml
        2024-07-17_1741_H1SUSOFI_M1_WhiteNoise_Y_0p02to50Hz.xml

        2024-07-17_1950_H1SUSOFI_M1_WhiteNoise_L_0p02to50Hz.xml % damped
        2024-07-17_1950_H1SUSOFI_M1_WhiteNoise_T_0p02to50Hz.xml
        2024-07-17_1950_H1SUSOFI_M1_WhiteNoise_Y_0p02to50Hz.xml