Andrei, Naoki, Sheila

For the upcoming measurement of the FC backscattering, we need to calibrate the length change of the FC. To do this, we calculated the transfer function from the GS_SL FC control signal [Hz] to FC2 displacement [μm]. We followed the steps in Diagram.png to get to result. The plot bode_all_datasets.png contains all the used datasets.

The resulting transfer function is presented here: Tranfer_func.png (where Result curve is the transfer function). The result was exported to frequency/magnitude/phase dataset and can be found in result_data.txt. The remaining .txt files contain all the used datasets for this calculation.

Assuming that the frequency of the FC resonance shift Δf equal to c/2L corresponds to the FC length change ΔL equal to λ/2. (λ = 532 nm, L = 300 m), then Δf/ΔL = c/(L * λ) = 1.88*10¹²  [Hz/m] = 1.88*10⁶  [Hz/μm]. Multiplying Transfer function by this coefficient will get us the open loop unity gain frequency of 39.4 Hz. Open-loop gain plot (after multiplication) can be found in the following figure: openloop_gain.png.

TITLE: 06/28 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 5mph 5min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY: H1 has been locked and observing for over 4 hours.

• Wind and microseism are low
• All other systems nominal

For Robert's tests of changing the ITM L3 bias, I unmonitored a few things to allow him to make changes while we are in observing as approved. These will need to be remonitored at the end of teh weekend. I made the changes while in observing, which didn't knock us out of observing, but I failed to notice that the offset switch was monitored and when Robert changed it we did go out of Observing. Good to know that we can unmonitor channels while in observing.

Unmonitored:

H1:SUS-{ITMX, ITMY}_L3_LOCK_BIAS_{GAIN, TRAMP, OFFSET}

H1:SUS-{ITMX, ITMY}_L3_LOCK_INBIAS

Fri Jun 28 10:09:37 2024 INFO: Fill completed in 9min 33secs

Jordan confirmed a good fill curbside.

While restarting an IOC on cdsioc0 this morning I ran into the IETF GPS leap seconds missing web page issue (reported a year ago in alog71075)

   RuntimeError: Error loading leap file: https://www.ietf.org/timezones/data/leap-seconds.list

The local leapsconds file is managed by the tzdata package, after upgrading this on cdsioc0 the problem was resolved. I checked the leapsecond files are correct on workstations and h1guardian1, it looks like cdsioc0 slipped through.

A rather short lock, no immediate cause. This lock loss (1403628990) did NOT see the DARM wiggle that we have been seeing frequently, but rather it looks like all of the quads start to move before DARM.

After a night of earthquakes, we are back to Observing. Fully auto from me after I requested an initial alignment.

TITLE: 06/28 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Earthquake
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 2mph Gusts, 1mph 5min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.06 μm/s
QUICK SUMMARY: Ground just getting calm after the 5.7 Tonga earthquake, which followed a 7.0 from Peru. I'll start initial alingment now.

TITLE: 06/28 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Earthquake
INCOMING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: EARTHQUAKE
    Wind: 13mph Gusts, 10mph 5min avg
    Primary useism: 0.46 μm/s
    Secondary useism: 0.06 μm/s
SHIFT SUMMARY:
H1 was locked for 6 + hours before a 7.2 Mag eathquake unlocked the IFO.
When the 7.2 Mag quake hit the ITMY ISI's tripped.  I was able to simply untrip them with out any issue.
Ive been sitting in Idle for a while and it seems like the IFO needs more time to allow the shaking to stop.

ISC_Lock is currently in Initial_alignment.

LOG:

 

TITLE: 06/28 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Earthquake
CURRENT ENVIRONMENT:
    SEI_ENV state: EARTHQUAKE
    Wind: 23mph Gusts, 18mph 5min avg
    Primary useism: 0.95 μm/s
    Secondary useism: 0.48 μm/s
QUICK SUMMARY:

Incoming Earthquake 7.0 mag from Peru.
Lockloss at 5:48 UTC ended the 6 hour 45 minute lock we had.
Holding in ISC_Lock in IDLE  for a while.

Repeat the same measurement (as 78686) on SHG1, all the phase matching curve was measured in cavity.

The measurement was done twice, the mode matching was 85% for the first measurement and 93% for the second measurement. The alignment optimization does not affect the curve.

Next: remove one of the cavity mirror and measure the phase matching curve in single pass setup.

TITLE: 06/27 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Currently Observing and have been Locked for 21 minutes. Lots of issues with ALSX PLL today (78703), as a continuation/extension of the problems we have been having with ALSX the past few days. After troubleshooting and multiple hours down after the 17:08 lockloss, we seemed to be clear of the PLL unlocking issue after I noticed that the PLL had managed to stay locked for 25 minutes, and then relocking went just like normal.
LOG:

14:30 Detector Observing at 155Mpc and has been Locked for almost 5 hours

15:32 Out of Observing for calibration measurements (78699) and commissioning
    15:39 bb done
    16:01 Simulines done
16:03 Lockloss right at beginning of commissioning
16:04 Started an initial alignment
    - had to touch up ALSY because increase flashes couldn't catch it
16:41 Initial alignment done, going to sit in DOWN for commissioning test
17:08 Starting relocking
    - Lockloss from LOCKING_ARMS_GREEN x2
    - earthquake starts rolling through
    - Lockloss from ACQUIRE_PRMI
    - Held in GREEN_ARMS_MANUAL to check for issues with ALSX PLL
    - Lockloss from FIND_IR x3
18:06 I started another initial alignment, skipping over green GREEN_ARMS_MANUAL
18:19 Initial alignment done, relocking
    - CHECK_CRYSTAL_FREQUENCY for ALSX
    - lockloss from LOCKING_ALS
    - CHECK_CRYSTAL_FREQUENCY for ALSX
    - Lockloss from FIND_IR x 2
- Sitting in GREEN_ARMS_MANUAL due to ALSX PLL unable to stay locked, even when ALSX is in the UNLOCKED state 

20:03 Trying relocking after I saw that the last PLL error was from 25 minutes ago
    - Everything worked perfectly
20:45 NOMINAL_LOW_NOISE
20:48 Observing

21:45 Lockloss
21:48 Initial alignment
22:09 IA done, relocking
23:01 NOMINAL_LOW_NOISE
23:04 Observing                                                                                                                                                                                                                                                                                                                                                               

TITLE: 06/27 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
OUTGOING OPERATOR: Oli
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 11mph Gusts, 8mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.07 μm/s
QUICK SUMMARY:

H1 is currently observing and every thing seems to be functioning as expected.
 

RyanC, Oli, Rahul

As reported before (LHO alog 78574 and 76635) we have assembled and characterized in total five A+ HRTS Freestanding version for O5. In this alog I am posting a comparison plot of all five suspensions (assembly S/N 03, 08, 01, 02, 11 ) for their transfer function measurements, please find them attached below (the second file is the zoomed-in version of the first. Looking at their resonant peaks, shapes and magnitude, I think all five suspensions are very much on top of each other. These results also ties up very well with the model (blue trace). The Y_dof for suspension assembly SN 11 (green trace - see page 6) has slightly higher magnitude above 3Hz. I am still investigation what could be the reason for that.

Lockloss 06/27 @ 21:45UTC

Oli, Sheila, Jim, Camilla

We've been having trouble keeping the ALS X arm locked, so Oli put the request for the X arm guardian to "UNLOCKED" which means that it asks the PLL to lock and nothing else.  We've been sitting here for 15 minutes and see that the PLL can't stay locked in this configuration where the ground motion doesn't matter and the laser should easily stay locked.

The second two attachments show how much the fiber beatnote depends on outdoor temperature, it is now varying by more than 20dBm, while last summer with similar temperature swings it would only vary by 4dBm.  This year the problem seems to be coming and going, for about a week at a time the temperature dependence seems to go away. 

We won't be able to lock the IFO while the PLL is not staying locked like this, this problem seems to be coming and going recently, so it may explain a lot of IFO downtime.

Jennie W, Sheila

We want to do an OMC scan after unlocked today so we can estimate the mode-matching into the OMC with a hot OM2.

Set SRM, ITMX and ETMs to mis-aligned, IMC locked in guardian.

Ran DC centering loops 3 and 4 to centre on AS_A and AS_B QPDs, then ran OMC ASC to align into OMC_A and OMC_B QPDs. Waited for this to converge spots in centre of QPDs with current nominal QPD offsets.

Made sure that OMC guardian was paused then moved PZT2 slider to bottom of its range on ther OMC_Control screen and ran scan with template:

Did scan but sidebands are still on so can't do visibility measurement easily.

Ref 12-14 are today's scan measurements saved in /ligo/home/jennifer.wright/Documents/OMC_scan/2024_06_27_OMC_scan.xml.

Analysis ongoing.

The first attachment shows spectra (GDS CALIB STRAIN clean, so with calibration corrections and jitter cleaning updated and SRCL FF retuned) with OM2 hot vs cold this week, without squeezing injected.  The shot noise is slightly worse with OM2 hot, while the noise from 20-50Hz does seem slightly better with OM2 hot.  This is not as large of a low frequency improvement as was seen in December.  The next attachment shows the same no squeezing times, but with coherences between PRCL and SRCL and CAL DELTAL.  MICH is not plotted since it's coherence was low in both cases.  This suggests that some of the low frequency noise with OM2 cold could be due to PRCL coherence. 

The optical gain is 0.3% worse with OM2 hot than it was cold (3rd attachment), before the OMC swap we saw a 2% decrease in optical gain when heating OM2 in Decmeber 74916 and last July 71087.  This seems to suggest that there has been a change in the OMC mode matching situation since last time we did this test. 

The last attachment shows our sensitivity (GDS CALIB STRAIN CLEAN) with squeezing injected.  The worse range with OM2 hot can largely be attributed to worse squeezing, the time shown here was right after the PSAMs change this morning 78636 which seems to have improved the range to roughly 155Mpc with cleaning; it's possible that more psams tuning would improve the squeezing further. 

Times used for these comparisons (from Camilla):

• no sqz OM2 hot  cold 24/06/2024 12:18:00 UTC
• no sqz OM2 cold hot 24/06/24 23:52:10 UTC
• sqz with psams adjusted OM2 hot 25/06/2024 13:34:52 UTC
• sqz OM2 cold 16/06/2024 11:51:20 UTC

At the start of commissioning today, before we got to NLN and were having trouble locking the OMC, I took an OMC mode scan when we were locked at 10W.

We manually move the OMC_PZT2_OFFSET to its lowest slider value then run the template which does two 100s ramps of this PZT.

Posting for posterity.

Time of Scan = 15:23:43 UTC

200s length. See template in /ligo/home/jennifer.wright/Documents/OMC_scan/2024_06_06_OMC_Scan_15-23UTC.xml