The FMCS team has their own set of alarms for the reverse osmosis (RO) system. I've removed this alarm in the Alarm Handler system in the control room. Operators will no longer need to alert the FMCS team of RO related issues unless there are major problems.

The file for this is symlinked in /opt/rtcds/lho/h1/alh/fmcs/ to /opt/rtcds/userapps/release/cds/h1/alarmfiles/fmcs.alhConfig and is under svn control.

4 pressure gauges were replaced today after the previous set was damaged during the runaway of EY Chiller 1. (2 per supply and return line)

There is some ambiguity between most of these gauges across all AHU's. Because the new gauges all read nearly exact pressures I will likely replace most/all others in the near future.

I also observed about 10psi of pressure loss since replenishing on friday. Glycol was added via the makeup tank to get back to a 30psi operating pressure. The EY makeup tank now has about 50% capacity.

T. Guidry

2053 Lock loss (1377550449) after exactly 27 hours. No immediate cause.

L. Dartez, J. Kissel

More details to come, but as of 2023-08-31 19:10:00 UTC (12:10 PDT), we've updated several corners of the calibration for the first time since Jun 21 2023 (see LHO:70693) in order to:
    - Update the static model of the test mass actuation strength, to better match the current time-dependent-correction factor value (because it had gotten large enough that approximations used in all TDCF calculations would have started to breakdown) (LHO:72416)
    - Update the "DARM loop modeled transfer functions at calibration line frequencies" EPICs records in order to account for the new DARM2 FM8 boost (LHO:72562 and LHO:72569)
    - Update the sensing function (only a little bit) because we're now regularly operating with OM2 "hot" as of 2023-07-19 (LHO:72523)
    - start using the newly re-organized pydarm librarianship, including the use of new simulines-measured IFO sening and actuation function data. (aLOG pending)
    - fixed an unimpactful bug in the front-end computed version of the live measured response function systematic error, in which the local oscillator frequency for the demod that was demodulating the recently changed 102.13 to 104.23 Hz calibration had not been updated. (to be commented below)

The exciting news is that, with all the metrics we have on hand, these calibration updates made everything better.
    - 1st attachment: at the boundary of the change, we see the "relative" time-dependent correction factors change rapidly from non-unity values to unity values (and the cavity pole doesn't change, as expected).
    - 2nd attachment: at the boundary of the change, we see the front-end computed live measured response function systematic error goes from large values to values close to unity magnitude and zero phase.

We're still tracking down some bugs in the *modeled* systematic error budget that has been broken since yesterday, Aug 20 2023 19:50 UTC *and* we're not sure if the *GDS* processed live measured response function systematic error is running yet, but we'll keep you posted.

The comments below will also contain some updated details on the process for this update.

Following the usual instructions on the wiki, I took a broadband measurement followed by the simulines.

Start time:

PDT: 2023-08-31 12:35:20.025399 PDT
UTC: 2023-08-31 19:35:20.025399 UTC
GPS: 1377545738.025399
 

End time:

PDT: 2023-08-31 12:57:25.118313 PDT
UTC: 2023-08-31 19:57:25.118313 UTC
GPS: 1377547063.118313

2023-08-31 19:57:24,730 | INFO | File written out to: /ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOL
G_SS_20230831T193521Z.hdf5
2023-08-31 19:57:24,760 | INFO | File written out to: /ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCA
LY2DARM_SS_20230831T193521Z.hdf5
2023-08-31 19:57:24,771 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUS
ETMX_L1_SS_20230831T193521Z.hdf5
2023-08-31 19:57:24,782 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUS
ETMX_L2_SS_20230831T193521Z.hdf5
2023-08-31 19:57:24,793 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUS
ETMX_L3_SS_20230831T193521Z.hdf5

While running initial alignments, we have been getting saturations for OM1 and OM2 when running through the DOWN state of ALIGN_IFO. These have been traced back to the yaw integrators for each suspension's top mass not being properly cleared. Since it seems like the integrators are, in fact, being cleared but then immediately filled up again, I've moved the clear integrators step to be the last step done in the DOWN state and added a one second wait timer right before it. This hopefully gives more time for everything to settle before the top mass integrators are cleared, but we'll see the next time an initial alignment is run.

ALIGN_IFO has been loaded and changes committed to svn.

All dust monitor pumps are operating within temp and pressure specs.

Thu Aug 31 10:07:07 2023 INFO: Fill completed in 7min 3secs

TITLE: 08/31 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Observing at 154Mpc
OUTGOING OPERATOR: Austin
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 5mph 5min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.11 μm/s
QUICK SUMMARY: Locked for 21 hours. PR2, SR2, MC2 saturation at 1132 UTC, but no obvious seismic or other enviromental noise a that time.

CDS overview - OK

Below is the summary of the DQ shift for the week of 21-27 August 2023

• Average range during observing was 140-152 Mpc. The duty cycle each day was M 95.8%, Tu 69.9%, W 75.7%, Th 100%, F 92.9%, Sa 71.4%, Su 86.0% for an average for the week of 85.5%. The long observing period from 22:55 UTC on 23 Aug to 20:19 UTC on 25 Aug of 45h 24m occurred during a record O4 lock of 60h 29m (see aLog 72446).
• The h(t) spectrogram looks clean although the line from 511 Hz violin mode fundamental (and sometimes higher harmonics) are visible and strong at the start of observing periods arising from an unlocked state. This is also true for the 102 Hz line.
• The squeezer (SQZ) system apparently caused the lock loss at 22:59 UTC on 21 August (see aLog 72363)
• As expected, there was excess ground motion during an unlocked period due human acitivity on Tuesday maintenance day.
• H1:PEM-EX_VMON_ETMX_ESDPOWER48_DQ was the hVeto Round 1 or 2 winner every day as it has been throughout O4. ETMX OPLEV channels (e.g., H1:SUS-ETMX_L3_OPLEV_YAW_OUT_DQ) also appeared frequently. On 22 Aug, the HVeto Round 1, Winner was H1:IMC-WFS_B_Q_YAW_OUT_DQ which seemed somewhat unusual. On 23 Aug, another uncommon winner was H1:PSL-ISS_PDB_REL_OUT_DQ. The rest of the week did not show any of these unusual channels.
• On 25 and 26 Aug, SEI/BLRMoverview data missing after 22:00 UTC. On 27 Aug, it stops (at least so far) at 20:00 UTC. This is probably true also for other SEI pages.
• One or both (all frequencies and up to 500 Hz) of the glitchgram and glitch rate plots did not complete starting on 24 Aug.
• A brief increase in the lowest SNR glitch rate was observed on 24, 25, and 27 Aug but only for the high frequency plot.
• A lock was ended due to the failure of a chiller on 25 August (see aLog 72369)
• LASSO picked out 2 potentially interesting channels that appear to correlate with the range drop : H1:HPI-HAM2_ISO_Y_OUT16 and H1:HPI-ITMY_TWIST_FB_Y_INMON. The first of these had many additional channels correlated with it. Both channels seemed to change with the range drop beginning at about 16:30 UTC on 26 August.
• A peculiar noise feature during Observing at about 14:10 UTC on 22 Aug looks like a possible injection.
• FScan Observing shows the number of lines was highest (higher than on 20 Aug) on 21 Aug but below the threshold and fluctuated at lower values throughout the week. Five combs were visible from 21 Aug through 25 Aug. Six combs were visible on 26 - 27 Aug. (It should be noted that the Interactive Spectrum plots do not load for those with slow internet.)

The complete DQ shift report may be found here.

TITLE: 08/31 Eve Shift: 23:00-07:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 154Mpc
INCOMING OPERATOR: Austin
SHIFT SUMMARY:

Very quiet evening with one candidate event, S230831e. H1 was locked and observing for the whole shift; current lock stretch is at 13 hours.

LOG:

No log for this shift.

State of H1: Observing at 151Mpc

H1 has been locked for 9 hours and observing the whole shift. One candidate event two hours ago, S230831e, quiet evening otherwise.

Elenna, Gabriele, Camilla 

This afternoon we updated the MICH Feedforward, it is now back to around the level it was last Friday, comparison attached. Last done in 72430. Maybe need to be done so soon because of the 72497 alignment changes on Friday.

The code for excitations and analysis has been moved to /opt/rtcds/userapps/release/lsc/h1/scripts/feedforward/

Elenna updated in guardian to engage FM1 rather than FM9 and sdf accepted. New filter attached. I forgot the accept this in h1lsc safe.snap and will ask the operators to accept MICHFF FM1 when we loose lock or come out of observe(72431), tagging OpsInfo.

Attached is a README file with instructions.

I ran a 2nd calibration sweep today, starting with broadband:

/ligo/groups/cal/H1/measurements/PCALY2DARM_BB/PCALY2DARM_BB_20230830T212846Z.xml

Simulines:

2023-08-30 21:58:00,615 | INFO | Commencing data processing.
2023-08-30 21:58:56,567 | INFO | File written out to: /ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOLG_SS_20230830T213653Z.hdf5
2023-08-30 21:58:56,585 | INFO | File written out to: /ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCALY2DARM_SS_20230830T213653Z.hdf5
2023-08-30 21:58:56,611 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUSETMX_L1_SS_20230830T213653Z.hdf5
2023-08-30 21:58:56,636 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUSETMX_L2_SS_20230830T213653Z.hdf5
2023-08-30 21:58:56,661 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUSETMX_L3_SS_20230830T213653Z.hdf5

GPS start: 1377466629.697354

GPS stop: 1377467954.983395

Vicky, Naoki, Sheila, Daniel

Details of homodyne measurement:

This morning Daniel and Vicky reverted the cable change to allow us to lock the local oscillator loop on the homodyne (undoing change described in 69013).  Vicky then locked the OPO on the seed using the dither lock, and increased the power into the seed fiber to 75mW (it can't go above 100mW for the safety of the fiber switch).  We then reduced the LO power so that the seed and LO power were matched on PDA, and adjusted the alignment of the sqz path to get good (~97%) visibility measured on PDA.  We removed the half wave plate from the seed path, without adjusting the rotation.  With it removed, we checked the visibility on PDB, and saw that the powers were imbalanced.

Polarization issue (revisiting the polarization of sqz beam, same conclusion as previous work):

There is a PBS in the LO path close to the homodyne, so we believe that the polarization should be set to horizontal at the beamsplitter in that path.  The LO power on the two PDs is balanced (imbalanced by 0.4%), so we believe this means that the beamsplitter angle was set correctly for p polarized light as we found it, and there is no need to adjut the beamsplitter angle.  However, when we switched to the seed power, there is a 10% difference between the power on the two PDs without the halfwave plate in the path.  We put the halfwave plate back, and the powers were again balanced (with the HWP angle as we found it).  We believe this means that the polarization of the sqz path is not horizontal arriving at the homodyne, and that the half wave plate is restoring the polarization to horizontal. If the polarization rotation is happening on SQZT7, the half wave plate should be able to mitigate the problem, if it's happening in HAM7 it will look like a loss for squeezing in the IFO. Vicky re-adjusted the alignment of the sqz path after we put the HWP back in, because it slightly shifts the alignment.  After this the visibility measured on PDA is 95.7% (efficiency of 91.6%) and on PDB visibility is 96.9% (efficiency of 93.9%). 

SQZ measurements, unclipping:

While the IFO was relocking Vicky and Naoki measured SQZ, SN, ASQZ and mean SQZ on the homodyne and found 4.46dB sqz, 10.4dB mean sqz and 13.14dB anti-sqz measured from 500-550Hz.  Vicky then checked for clipping, and saw some evidence of small clipping (order 1% clipping with 10urad yaw dither on ZM2).  We went to the table to check that the problem wasn't in the path to the IR PD and camera, we adjusted the angle of the 50/50 beamsplitter that sends light to the camera, and set the angle of the camera to be more normal to the PD path.  This improved the image quality on the camera.  Vicky moved ZM3 to reduce the clipping seen by the IR PD slightly.  She restored good visibility by maximizing the ADF, and also adjusted both PSAMs, moving ZM4 from 100V to 95V.  (We use different PSAMs for the homodyne than the IFO).  After this, she re-measured sqz at 800-850Hz: 5.2dB sqz, 13.6dB anti-sqz, and 10.6dB mean sqz. 

Using the nonlinear gain of 11 (Naoki and Vicky checked it's calibration yesterday), and the equations from aoki, this sqz/asqz level implies total efficiency of 0.72 without phase noise, the mean sqz measurement implies a total efficiency of 0.704. From the sqz loss spreadsheet we have 6.13% known HAM7 losses, if we also use the lower visibility measured using PDA we should have a total efficiency for the homodyne of 0.916*0.9387 = 0.86.  This means that we would infer an extra 16-18% losses from these homodyne measurements, which seems too large for homodyne PD QE and optics losses in the path.  Since we believe that the polarization issue is reflected in the visibility, this means that these are extra losses in addition to any losses the IFO sees due to the polarization issue. 

Screenshot from Vicky shows the measurement made including the dark noise.

Since the results from yesterday's quarter bias test (66810) seem inconsistent with Wensday's test (66751), I'm trying a repeat of the test with lines on and off so that we can have the same number of averages for all these configurations. 

• full bias, lines off (NLN_CAL_MEAS) 19:49 UTC 1/14/2023 reference 46-50
• full bias, calibration and ADS lines on but awg lines off, 18:09:32 UTC 1/14/2023 reference 51-55
• 1/4 bias, calibration and ADS lines on (Awg lines still off) 18:33:30 UTC reference 56-60
• 1/4 bias, lines off 18:50 UTC reference 61-65

The SRCL cleaning probably needs retuning because of the ring heater change, we've got pretty high SRCL coherence up to 50Hz right now.  This does reproduce that the noise is higher with 1/4 bias, and the result doesn't seem to depend on having the lines on or off.  For now I've left the IFO with all the lines back on and full bias, Robert will try some injections in a little while.  I'll add a plot to this alog later on.