Displaying reports 8661-8680 of 83922.Go to page Start 430 431 432 433 434 435 436 437 438 End
Reports until 16:00, Tuesday 30 April 2024
LHO General
ryan.short@LIGO.ORG - posted 16:00, Tuesday 30 April 2024 (77521)
Ops Day Shift Summary

TITLE: 04/30 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Oli
SHIFT SUMMARY: Busy maintenance day, but the initial alignment and lock acquisition that followed were straightforward. Lost lock shortly after starting to observe.

The LVEA remains Laser HAZARD for more potential viewport tests during commissioning time this week.

LOG:

Start Time System Name Location Lazer_Haz Task Time End
14:30 FAC Chris, Tyler MX, MY - HVAC fan greasing 15:35
15:00 CAL Jeff LVEA - HAM6 racks 15:45
15:01 FAC Kim, Karen FCES - Technical cleaning 15:33
15:03 FAC Mitchell MX - Grabbing case 15:18
15:10 VAC Gerardo MX, EX - Turbopump checks 17:40
15:11 SAF LASER HAZARD LVEA YES LVEA is LASER HAZARD Ongoing
15:13 SAF TJ LVEA YES Transition to HAZARD 15:19
15:15 FAC Eric MER - Heating coil maintenance 17:22
15:16 ISC Sheila, Jennie, Minhyo CR - Single bounce measurements 20:40
15:18 VAC Jordan, Janos All - CP tank repairs 17:05
15:18 VAC - EY - Dewar jacket pumping 17:05
15:22 ISC Jenne +1 LVEA - Tour 15:50
15:26 IAS Jason, RyanC LVEA - FARO surveying 18:46
15:28 SAF Travis All - Captial inventory 16:56
15:33 FAC Karen EY - Technical cleaning 16:30
15:33 FAC Kim EX - Technical cleaning 17:21
15:34 SEI Jim, Mitchell, TJ LVEA - Craning 3IFO storage container 17:15
15:35 FAC Tyler OSB Roof - Inspection 16:00
15:37 PEM Robert, Anamaria LVEA YES Beam hunting (VIEWPORTS OFF) 20:09
15:51 FAC Ken FCTE, LVEA - Cable tray installation 19:02
15:51 SAF Fil All - Interlock checks 18:35
16:01 FAC Tyler EX - Checking for bees 17:22
16:02 CAL Jeff LVEA - Getting SR785 data 16:07
16:41 SQZ Camilla, Naoki, Andrei LVEA - SQZT0 YES Adjust SHG pump AOM/fiber 18:10
17:21 FAC Karen, Kim LVEA - Tech clean 18:45
17:22 FAC Tyler OSB roof n Checking roof status 17:28
17:40 VAC Gerardo LVEA - Capital inventory 18:52
17:44 ISC Sheila LVEA - Turning off sidebands 17:50
17:52 SEI Jim FCES - Troubleshooting HAM8 GS13 18:56
18:15 IAS Tyler LVEA - FARO surveying 18:40
18:49 SUS Jason LVEA YES Troubleshooting ITMX oplev 18:59
19:00 ISC Sheila LVEA - Turning sidebands back on 19:04
19:37 SQZ Terry, Kar Meng Opt Lab LOCAL SHG work Ongoing
19:52 VAC Gerardo MY - Capital inventory 21:09
20:12 FAC Ken FCTE - Electrical work 21:12
20:20 PEM Robert, Anamaria LVEA - Cleanup & sweep 21:39
20:00 CDS Dave EX, EY, CER - Looking for laptops 20:54
H1 General
oli.patane@LIGO.ORG - posted 15:53, Tuesday 30 April 2024 - last comment - 16:53, Tuesday 30 April 2024(77528)
Lockloss

Lockloss at 04/30 22:50 UTC from unknown cause

Comments related to this report
oli.patane@LIGO.ORG - 16:53, Tuesday 30 April 2024 (77531)

23:52UTC Observing

H1 General
oli.patane@LIGO.ORG - posted 15:50, Tuesday 30 April 2024 (77527)
Ops EVE Shift Start

TITLE: 04/30 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 6mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.23 μm/s
QUICK SUMMARY:

Have been Locked for 52 minutes and just got to Observing

LHO VE (VE)
gerardo.moreno@LIGO.ORG - posted 15:45, Tuesday 30 April 2024 (77525)
X-Mid and X-End FAMIS Task for Turbo Pumps

Functionality test was done on the following stations:

X-Mid turbo pump station;
     Scroll pump hours: 215.2
     Turbo pump hours: 125
     Crash bearing life is at 100%

X-End turbo pump station;
     Scroll pump hours: 7143.2
     Turbo pump hours: 1093
     Crash bearing life is at 100%

FAMIS tasks 24850 and 24874.

H1 ISC
jennifer.wright@LIGO.ORG - posted 15:45, Tuesday 30 April 2024 - last comment - 04:52, Friday 10 May 2024(77520)
OMC Scans to investigate possible OFI bad throughput

Jennie W, Sheila

 

Today we took OMC scans to help diagnose what is going on with our alignment through the OFI - that is, what is the mode-matching at our the old alignment (as of Monday 22nd) and our new alignment (as of this morning).

 

Sheila turned off the sidebands before the test and we had the ETMs and the ITMX mis-aligned initially for single bounce configuration.

 

Old alignment: SR3 M1 YAW OFFSET = -125 microradians

SR3 M1 PIT OFFSET = -437 microradians

SR2 M1 YAW OFFSET = -421 microradians

SR2 M1 PIT OFFSET = -64 microradians

 

Due to PEM measurements we switched from single bounce off ITMY to single bounce off ITMX.

 

Locked time = 1 minute from GPS 1398534847

Unlocked time = 1 minute from GPS 1398534984

Scan = 200 s starting at 1398535070 GPS

 

New alignment: SR3 M1 YAW OFFSET =  120.2 microradians

SR3 M1 PIT OFFSET = 437.9 microradians

SR2 M1 YAW OFFSET = 2061.7 microradians

SR2 M1 PIT OFFSET = -5.5 microradians

 

Locked time = 1 minute from 1398538330 GPS

Unlocked time = 1 minute from 1398538461 GPS

Scan = 200 s starting at 1398537927 GPS

Dark time with IMC offline and fast shutter closed = 1398538774 GPS

 

Mode mis-match measurments pending...

 

Images attached to this report
Comments related to this report
jennifer.wright@LIGO.ORG - 21:40, Monday 06 May 2024 (77673)

The loss through the OMC appears to have increased after whatever happened to the output path on April 22nd.

I use again Sheila's OMC loss calculation code as we previously used in this entry.

Power on refl diode when cavity is off resonance: 29.698 mW

Incident power on OMC breadboard (before QPD pickoff): 30.143 mW

Power on refl diode on resonance: 5.153 mW

Measured effiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 56.5 %

assumed QE: 100 %

power in transmission (for this QE) 17.029 mW

HOM content infered: 14.415 %

Cavity transmission infered: 66.501 %

predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 56.494 %

omc efficency for 00 mode (including pick off BS, cavity transmission, and QE): 66.009 %

round trip loss: 3495 (ppm)

Finesse: 335.598

We compare these values to that found from our scans on the 16th April and it seems like the HOM content has increased substantially, the incident power has decreased, and the measured and predicted cavity efficiency has decreased by 3%.

It would be good to cross-check these figures against the other methods of checking the losses, such as DARM offset step and the mode mis-match I still need to calculate from the mode scan taken on the same day.

jennifer.wright@LIGO.ORG - 04:52, Friday 10 May 2024 (77749)

I forgot to run the same analysis for the locked and unlocked measurements we got at the old (pre April 23rd) alignment of SR2 and SR3.

Power on refl diode when cavity is off resonance: 25.306 mW

Incident power on OMC breadboard (before QPD pickoff): 25.685 mW

Power on refl diode on resonance: 5.658 mW

Measured effiency (DCPD current/responsivity if QE=1)/ incident power on OMC breadboard: 54.1 %

assumed QE: 100 %

power in transmission (for this QE) 13.885 mW

HOM content infered: 19.870 %

Cavity transmission infered: 67.970 %

predicted efficiency () (R_inputBS * mode_matching * cavity_transmission * QE): 54.061 %

omc efficency for 00 mode (including pick off BS, cavity transmission, and QE): 67.467 %

round trip loss: 3289 (ppm)

Finesse: 339.266

H1 ISC (AOS, SUS)
anamaria.effler@LIGO.ORG - posted 15:35, Tuesday 30 April 2024 (77522)
ITMX and ITMY oplev shifts after incursion

Robert, Jason, Anamaria

Today we used the oplev to determine the CP alignment for both ITMX and ITMY. We had to move the sender around to find all the beams so here I mark the shift in the beam location in case someone later wants to look at drifts. The ITMs were realigned slightly after our test so it's not good to 1urad but the oplevs drift around more than that anyway. I also had to choose times after lockloss and before relocking, to not have ASC interfere.

  ITMX P ITMX Y ITMY P ITMY Y
Before -8 -1 -20 1
After -10 5 6 2

Since people don't open the receiver box or the sender box very often we note:  
a) The beams on the oplevs are as large as the QPD which is not great, but depends what they're used for.
b) We found the ITMX oplev beam to be clipping on the nozzle baffle. Jason helped us shift the QPD and then we realigned to this new, more central location.
c) Replacing the sender cover is very difficult without causing a shift in the oplev beam, though we were quite careful to not touch the telescope while doing that. This is why we were not able to center them better.
d) I suppose the last few urad should be done with the QPD stages, but one has to be careful to check from time to time that it doesn't walk out of the aperture over time (which is smaller since the installation of nozzle baffles).

Images attached to this report
H1 ISC (ISC)
jennifer.wright@LIGO.ORG - posted 14:55, Tuesday 30 April 2024 (77513)
Walking the beam on the OFI

Jennie W, Sheila, Minhyo

 

Summary: We tried to walk the beam on the OFI with SR2 and 3 and cannot find another 'good spot' at least with moves in yaw of the SRC cavity axis.

 

Today we set the IFO up in single bounce with 10W input and ITMX mis-aligned. Then we moved the sliders back to what they were before Jenne made changes to them on Wednesday

Then we stepped SR2 down in yaw in steps of about 0.6 - 1.0 uradians and compensated for this movement on AS_C QPD by moving SR3 down in yaw also to recentre. Eevery few steps we had to tweak the pitch of SR2 or 3 in pitch as well as pitch motions of the SRs are slightly cross-coupled with yaw motions on the QPD.

Jeff then pointed out we should be moving SR3 first, as this is the mirror closest to the OFI so I switched to moving this mirror first and then SR2 to compensate. We tried to move the same amount down on SR3 that Jenne moved. The power got worse on AS_C, only imrpoving when we were very mis-centred in yaw on this QPD so that is not a good reference.

See a zoomed in image of the steps in SR2 and 3 and the effect they had on ASC-AS_A_DC_NSUM and ASC-AS_C_NSUM.

From this it looks as though the power throughput to ASC-AS_C (anti-symmetric port) was maximum when we were well-centred on ASC-AS_C just after the first cursor before we had started walking the beam.

I think this suggests that there is no small burnt spot in this degree of freedom across the OFI surface that we can walk to the other side of and see our throughput improve.

However the beam looked cleaner at points when it was positive in yaw on the QPD - not sure if this was real or not.

After these moves we reverted back (first cursor) to the alignment sliders we had before Jenne's moves on Wednesday 24th and took an OMC scan.

Then we went back to the 'nominal' alignment from this morning (second cursor) before maintenance started and took another OMC scan.

 

Images attached to this report
H1 ISC (SQZ)
camilla.compton@LIGO.ORG - posted 14:52, Tuesday 30 April 2024 - last comment - 16:42, Tuesday 30 April 2024(77518)
Translating SQZ beam for better AS_C alignment adn OMC thoughput

Naoki, Sheila, Camilla

After the output alignment shift reported in 77427, we tried to revert SQZ to the last successful SQZ-OMC scan in 77515 but when we increased throughput, AS_C alignment was bad. Today we translated the beam to get good throughput on AS_A/B and AS_C and a centered beam on AS_C with OMC DC centering loop running. This was a move of ZM4 -1000urad, ZM5 -650urad in yaw as reported by DAMP_Y_INMON channels

Attached shows previous April 16th OMC-SQZ scan compared to during today's translation and how we left the ZMs:

We're not sure how this change will effect in-lock SQZ as Vicky had to make big changed in 77400  and we may have seen that good OMC scan alignment isn't good SQZ alignment?

Images attached to this report
Comments related to this report
camilla.compton@LIGO.ORG - 16:42, Tuesday 30 April 2024 (77530)

Naoki, Sheila, Camilla

This alignment didn't give us good in-vac SQZ.

We tried taking SQZ sliders to before the output arm alinement shift when we had these PSAMS (2024/04/17 23:38 UTC) with the addition of the -1000urad, -650urad offsets on ZM4 and ZM5. This made SQZ worse.

We moved ZM6 to maximize RF3 and RF6 adn then went to anti-sqz and ran SCAN_ALIGMENT_FDS twice. SDFs attached.

Naoki adjusted the SQZ angle to squeezing and reran SCAN_SQZANG, this got us back to 4+dB of SQZ and over 150MPc of range, still room for improvement but much better than last week.

Images attached to this comment
LHO FMCS (PEM)
ibrahim.abouelfettouh@LIGO.ORG - posted 14:34, Tuesday 30 April 2024 (77519)
HVAC Fan Vibrometers Check - FAMIS 26299

Closes FAMIS 26299, last checked in alog 77457

Corner Station Fans (Screenshot 1)

- No notable increases in noise beyond threshold.

- Around 4.5 days ago, what looks to be a restart occured in all fans. Notably:

Outbuilding Fans ( Screenshot 2)

- No notable increases in noise beyond threshold.

- MX_FAN1_370 still producing pulses of higher and lower noise (long standing feature since at least alog 76942 (April 3 2024)

- MY FAN 1 was turned on while FAN 2 was turned off. MX Fan 2 was turned on while FAN 1 was turned off. This is expected and logged through Tyler's WP 11819, which is the "Quarterly lubrication of Axivane fans".

Images attached to this report
H1 ISC
sheila.dwyer@LIGO.ORG - posted 14:27, Tuesday 30 April 2024 - last comment - 15:50, Tuesday 30 April 2024(77517)
re-ran A2L script

This morning I came into the control room as the magnetic injections were finishing, and ran the a2l script while the charge measurements ran.

I did this because after Jennie Wright ran A2L yesterday afternoon it was not well tuned: 77495

When Jennie ran it yesterday, the coherence was over the threshold for all 8 gains, so all 8 were adjusted.  This morning I ran it and the coherence was below threshold for ITMX P2L and ETMY Y2L, so those were not updated.  I increased their amplitudes in the run_all_a2L.sh script, but as I was re-running the IFO unlocked due to the charge measurements.

The attached screenshots show how it changed the optics that it did run for, this is a large difference from the values that Jennie got yesterday.  Jennie W ran the script 20 hours into the lock, while I ran it 37 hours into the same lock, so these were both with a well thermalized IFO. 

It seems that there may be two problems we are facing with tuning A2L, one that our process doesn't seem to always work well to minimize A2L, and second that it seems that the values may be changing over the course of a lock.

Images attached to this report
Comments related to this report
sheila.dwyer@LIGO.ORG - 15:50, Tuesday 30 April 2024 (77526)

Ran again right at the start of the lock this time, with higer amplitudes.

The coherence improved but is still bad.

We will have to look into this tomorow.

Images attached to this comment
H1 General
minhyo.kim@LIGO.ORG - posted 14:03, Tuesday 30 April 2024 - last comment - 11:32, Monday 03 June 2024(77511)
OMC beam profile measurement-single bounce beam

Minhyo

Tried move the beam on OMC QPD using single bounce beam (ITMX misaligned). Changed OM3 PIT & YAW from 18:04:45 UTC (gps: 1398534729).
- Tried same task with OM3, with turning off ASC centering, OMC centering, started new from 18:21:00 UTC (gps: 1398536470).
 

After finishing with OMC QPD, reverted all settings with OM3 and then moved to OM2.
- Moved OM2 PIT&YAW to check ASC-AS_A & B. Finished at 18:35:00 UTC (gps: 1398537318)

Same job was done (moving OM3 -> OM2) with SQZ beam on OMC (from 20:12:05 UTC to 20:24:00 UTC, gps:1398543158-1398543858)

Screenshots (ndscope) are: 1) Measurement with single bounce beam, 2) Measurement with SQZ beam
 

 

Images attached to this report
Comments related to this report
minhyo.kim@LIGO.ORG - 09:36, Monday 03 June 2024 (78203)

Summary of OMC-QPD profile measurement

Qualitative comparison of beam profile between single bounce (SB) beam and squeezer (SQZ) beam, arriving at the OMC-QPD. These measurement are done by comparing PIT and YAW response with OM3 movements. PIT and YAW response at around the center is expected to be inversely proportional to the beam diameter.


The valid data of each beam can be obtained
1) SB: 18:08:00 ~ 18:19:48 (UTC) -- with WFS centering on
2) SQZ: 20:12:00 ~ 20:18:00 (UTC) -- w/o WFS centering (mistake)

Since AS_C centering was off, it would be not perfect data, but judging from those measurement, SQZ beam is smaller than the SB beam. The 
Below table is showing the relative ratio between SB and SQZ, with PIT and YAW individually.

  QPD A QPD B
PIT  14.4%  25.3%
YAW  30%  31%

Added screenshots of comparison: 1) PIT comparison, 2) YAW comparison
Red lines are the plots that applied with the low-pass filter, and dashed lines are linear fitted lines in the range of (-1, 1) for both PIT and YAW.
 

Images attached to this comment
minhyo.kim@LIGO.ORG - 10:35, Monday 03 June 2024 (78210)

Minhyo, Keita

As the PIT response on both QPD A and B are noisy, Keita and I checked for the source of that noise. By looking at multiple channel (1st screenshot), we found that ASC-AS_C PIT is also showing large noises. 

Keita checked on the witness sensors of the mirrors before ASC-AS_C, and found out that beam splitter (BS) mirror is also showing large oscillation at around the SB measurement time (2nd screenshot). Checking with the ITMX(Y) status, it seems that BS is noisy after making single bounce (SB) beam condition.

After checking with the power spectrum data of SUS-BS_OPLEV_PIT_OUT_DQ (3rd screenshot), we noticed that the noise is higher during the SB measurement under 10 Hz, which is also showing large coherence with ASC-AS_C_PIT. We still don't know the exact origin of this noise, but it have definitely affected the beam's PIT movement beyond BS.

 

Images attached to this comment
minhyo.kim@LIGO.ORG - 11:32, Monday 03 June 2024 (78213)

Minhyo, Keita
(Accidently didn't write alog about this, so I'm posting this in the comment)

We tried to measure the beam diameter that falls onto OMC-QPD (T1000276). The theory is to use the center gap of QPD as a calibration source, measuring the QPD SUM output data can give the information about the beam radius, since the power loss will occur due to the center gap in the QPD. It is expected that the SUM output will be minimum at the center, and gradually increase in respect to the offset from the center of QPD. 

The measurement was done with single-bounce (SB) beam condition, during 2024-03-19, 18:30:00 ~ 19:30:00 (UTC). At first, we tried to center the beam by using SR2, AS_C centering loop and WFS centering. After that, tried to center the beam with using OMC servo with mastergain=0.1. The actual measurement time is in between 19:04:30 ~ 19:22:00 (UTC), and moved OM1 and OM2 manually, to move the beam off from the center (1st figure).

However, by checking on H1:ASC-OMC_A(B)_SUM_OUT16 channels, it didn't show the trend what we were expected. In almost all times, the power output showed consistent trend, and QPD A even showed highest value around the center of QPD (2nd, 3rd figure). Whereas, WFS sensor (AS_A and B) showed the expected increasing trend of power in respect to the offset from the center (4th figure), even though they are using same photo diode model.

From discussion, we suspect two origin for the descrepancy from the expected trend; 1) The center gap of QPD model (InGaAs-Q3000) is different from the cataloue (0.045 mm), 2) Quantum efficiency of QPD is not consistent in near the edge of each quadrant diode.

In conclusion, the quatitative measurement of beam profile of OMC using the center is limited due to the uncertainty of the QPD.

Attached figures are: 1) Visualization of the beam movement and power in each OMC-QPD, 2) Time series data of QPD channels, 3) OMC-QPD SUM_OUTPUT data in respect to the offset from the center, 4) WFS (AS_A and B), and AS_C OUTPUT data in respect to the offset from the center

Images attached to this comment
H1 SEI (SEI, SUS)
ibrahim.abouelfettouh@LIGO.ORG - posted 13:47, Tuesday 30 April 2024 (77516)
Quarterly Inspection of HWWD Trends - FAMIS 26507

Closes FAMIS 26507

All channels had switches in the last quarter (screenshot 1)

EX had considerably less switches up until March 8th. I looked at the alog for this time but found nothing in particular. (screenshot 2).

Since all channels have switched in the last quarter, no further action is needed (per FAMIS task instructions).

Images attached to this report
LHO General
ryan.short@LIGO.ORG - posted 13:29, Tuesday 30 April 2024 (77514)
Ops Day Mid Shift Report

Maintenance activities have wrapped up (was extended by ~1 hour) and now starting an initial alignment. Robert will do an LVEA sweep shortly.

The LVEA remains Laser HAZARD.

H1 SEI
jim.warner@LIGO.ORG - posted 12:18, Tuesday 30 April 2024 - last comment - 09:49, Friday 10 May 2024(77512)
HAM8 H1 GS13 troubleshooting today

I went to FCES this morning to try to troubleshoot the sort of busted H1 GS13 on HAM8. I suspect there is something going on with the cable or interface chassis, but it's not something I think I've seen before. I tried swapping cables at both the rack and the chamber, and whenever the corner 1 chassis was connected to the H1 sensor, the transfer function from the H1 CPS to the H1 sensor would be half the magnitude of the other two sensor pairs. ASDs also show the H1 GS13 has half gain when the corner 1 sensors are connected to the corner 1 chassis. However, when the H1 sensor was plugged into the corner 2 or 3 chassis, all three sensor pair tfs would have the same amplitude. I could repeat this consistently, didn't matter how I swapped the cables around, as long as the H1 sensor wasn't plugged into the correct chassis all the l2l sensor tfs would look normal.

Attached plot shows two sets of data I took during this period, red blue and light green are the normal config, dark green, pink and light blue are with the H1 sensor on the corner 3 chassis, H3 sensor on the corner 1 chassis.

I will talk to Fil, but maybe in a couple weeks we can try running a temp cable from the FC mezzanine to the chamber, and see if that changes anything.

Images attached to this report
Comments related to this report
brian.lantz@LIGO.ORG - 09:49, Friday 10 May 2024 (77758)

Issue is tracked in FRS 31005

H1 SQZ
andrei.danilin@LIGO.ORG - posted 11:52, Tuesday 30 April 2024 (77507)
Fiber polarization aligned

Andrei, Camilla

We aligned the fiber polarization to minimize the H1:SQZ-SHG_GR_DC_POWERMON channel, following the instructions of Report 71761 on rotating the waveplates.

The reduction in monitor power is depicted in the attached screenshot (POWERMON_lesser_timespan.png), showing a decrease from 0.24 [a.u.] to 0.03 [a.u.].

The fiber currently in use (Fiber.png) is SM980-5.8-125 - Single Mode Optical Fiber, 980 - 1550 nm, Ø125 µm Cladding. As it seems from the figure POWERMON_large_timespan.png, power is unstable in the long term. We propose to change the fiber to PS-PM980 - 970 - 1550 nm PM Photosensitive Fiber, 0.12 NA, 6.6 µm MFD and to tightly fixate the optical cable on the optical table to furhter reduce polarization shift.

Images attached to this report
H1 SQZ
naoki.aritomi@LIGO.ORG - posted 11:48, Tuesday 30 April 2024 (77508)
Pump AOM and fiber alignment

Naoki, Andrei, Camilla

We aligned the pump AOM and fiber following 72081.

We set the ISS drivepoint at 0V and measured the AOM throughput. The throughput was 34 mW/59 mW = 58%. We aligned the AOM and got 65 mW/69 mW = 94% throughput.

Then we set the ISS drivepoint at 5V and aligned the AOM to maximize the 1st order beam. The 1st order beam improved from 4.5 mW to 15.7 mW. The 0th order beam is 34.9 mW.

We set the ISS drivepoint at 0V and measured the AOM throughput again. The throughput is 51.7 mW/77 mW = 67%. Although the throughput is improved by 10%, we could not improve more than that.

Then we aligned the pump fiber. The H1:SQZ-OPO_REFL_DC_POWER improved from 3.4 to 3.7.

H1 CDS
david.barker@LIGO.ORG - posted 10:22, Sunday 28 April 2024 - last comment - 15:40, Tuesday 30 April 2024(77473)
Restarted picket-fence, it has stopped 03:37:04 UTC Sun 28 April 2024

Another picket fence issue at 03:37 UTC, I think the third in the past few weeks. I restarted the process on nuc5.

Comments related to this report
david.barker@LIGO.ORG - 11:29, Monday 29 April 2024 (77485)
edgard.bonilla@LIGO.ORG - 15:40, Tuesday 30 April 2024 (77524)

Thank you for this summary. I will go dig in the code to see what is happening.

On first glance: the array of data should never be empty on an update, but somehow it is happening some times. I will add a failsafe (or an assert) so that the code can handle this exception and hopefully be more robust.
 

H1 ISC
sheila.dwyer@LIGO.ORG - posted 07:34, Saturday 27 April 2024 - last comment - 15:38, Tuesday 30 April 2024(77460)
Step in Clean range around 5:20 this morning

There was a drop in clean range around 5:20 this monrning, which doesn't seem to be a reapeat of the output arm shift we had earlier this week. 

Attached is a trend of the DARM blrms (based on DARM error, no calibration corrections or cleaning) and comparison of the cleaned and corrected range against the CAL-DELTAL range, only the cleaned channel sees the drop.  This made me concerned that we had a drop in optical gain, but the trend of the time dependent calibration correction factors doesn't show anything happening at this time. 

I don't know what would cause a sudden change in the clean range, since I don't think that the jitter subtraction would cause a sudden change like this.

Images attached to this report
Comments related to this report
jenne.driggers@LIGO.ORG - 15:38, Tuesday 30 April 2024 (77523)CAL

I'm still not at all sure why this drop happened, particularly if Sheila notes that there were no changes in the calibration TDCFs.  However, the drop is seen in all of the GDS-CALIB_STRAIN channels, not just a drop in the _CLEAN channel.  This indicates that the range drop comes from earlier in the process than the line subtraction or the cleaning. 

The crosshair in the attached plot is the same time as the crosshair in Sheila's plot, just to make it a little easier to orient and compare the plots.

Blue: Range from CAL-DELTAL_EXTERNAL

Green: Range from GDS-CALIB_STRAIN

Red: Range from GDS-CALIB_STRAIN_NOLINES

Orange: Range from GDS-CALIB_STRAIN_CLEAN

Images attached to this comment
H1 ISC (SQZ)
camilla.compton@LIGO.ORG - posted 15:48, Wednesday 24 April 2024 - last comment - 13:38, Tuesday 30 April 2024(77389)
Checking on SQZ to OMC power, can only get power back with ~200urad offsets

Sheila, Camilla, Jennie + CR

After Jenne got AS port power back with large SR2/3 yaw offsets in 77388, Sheila wanted to check we could get our SQZ beam back to the power levels we had during the SQZ to OMC scan in 77213 (~75 counts on AS_A and AS_B NSUMs).

We revered ZMs (alignment and PSAMs), SRM, OM1, OM2 to that scan time: April 16th 19:10UTC. But in the old alignment we can only see ~10 on AS_A AS_B NSUM, plot from Sheila attached. So something has changed in the alignment in the SQZ to OMC path too: SQZ, ZM4,5,6, OFI, SRM, OFI, OM1, OM2.

From this old OMC-SQZ scan alignment, by pitching ZM5 200urad (sliders) we could get back to 75 on NSUM plot (AS_AIR beam too low off camera). OR  by yawing ZM5 ~150urad (190urad on sliders/ 130urad on osems) we could get back to 70 on NSUMs plot (AS_AIR camera looks better). 

Reverting PSAMs back to nominal. 

Images attached to this report
Comments related to this report
camilla.compton@LIGO.ORG - 13:38, Tuesday 30 April 2024 (77515)

Sheila, Camilla. Relooked at the times from the original SQZ_OMC scan (04/16) to the checked alignment back to this scan last week (04/24): when we moved ZM5 to increase power on AS_C, the alignment onto AS_C gets much worse, plot attached. AS_A/B can;t be trusted as much as the OM3_P is different. Today we translated he beam in yaw to investigate this, alog pending.

Images attached to this comment
Displaying reports 8661-8680 of 83922.Go to page Start 430 431 432 433 434 435 436 437 438 End