Lock loss 1948 UTC

ETMX sees an odd move ~100ms before the lock loss just like yesterday. The lock loss tool also has a DCPD tag.

Back to Observing 1932 UTC

Observing at 1932UTC. A bit of a delay wrapping up commissioning today, but we're back to observing and locked for 20 hours.

Retuned SRM position and SRC1 offsets to increase coupled cavity pole

Jennie W, Keita, Sheila

Sheila suggested we move SRM to increase the coupled cavity pole as this got worse in the previous week.

Keita and I opened the SRC1_P and SRC1_Y loops (and turned off the offsets) then walked SRM in yaw and looked at the coupled cavity pole.

See image of the loop medm screen.

Its hard to see but moving down in SRM yaw on the sliders made the f_cc higher. We stopped due to the end of the commissioning period so maybe we could do more optimisation of this.

See the attached trend.

I set the offsets in the two loops to cancel out the INMON values at this new alignment, before closing them again.

These offsets have been changed in lscparams.py on lines 551 and 552 and accepted in OBSERVE.snap by TJ.

turned ITMY ESD bias to 0V

Robet mentioned while he was here that there was coherence with the ground current clamp in the vertex and DARM, and suggested that we try having both ITM biases set to 0V.  I did that today, and accepted the bias gain of 0 in OBSERVE and SAFE.snaps.

Robert also found that we need to change the bias at EX, which we haven't done yet.

DARM offset step

I ran the DARM offset step code starting at:

2024 Jun 13 16:13:20 UTC (GPS 1402330418)

Before recording this time stamp it records the PCAL current line settings and makes sure notches for 2 PCAL frequencies are set in the DARM2 filter bank.

It then puts all the PCAL power into these lines at 410.3 and 255Hz (giving them both a height of 4000 counts), and measures the current DARM offset value.

It then steps the DARM offset and waits for 120s each time.

The script stopped at 2024 Jun 13 16:27:48 UTC (GPS 1402331286).

In the analysis the PCAL lines can be used to calculate how the optical gain changes at each offset.

See the attached traces, where you can see that H1:OMC-READOUT_X0_OFFSET is stepped and the OMC-DCPD_SUM and ASC-AS_C respond to this change.

Watch this space for analysed data.

The script sets all the PCAL settings back to nominal after the test from the record it ook at the start.

The script lives here:

/ligo/gitcommon/labutils/darm_offset_step/auto_darm_offset_step.py

The data lives here:

/ligo/gitcommon/labutils/darm_offset_step/data/darm_offset_steps_2024_Jun_13_16_13_20_UTC.txt

 

 total_dcpd_light
 (dcpd_sum = 40mA)

 contrast_defect

 homodyne_angle

# craig lho:65000
contrast_defect   = 0.88    # mW  # measured on 2024 June 14, lho78413, 0.88 ± 0.019 mW
total_dcpd_light  = 46.6    # mW  # from dcpd_sum = 40mA/(0.8582 A/W) = 46.6 mW
import numpy as np
darm_offset_power = total_dcpd_light - contrast_defect
homodyne_angle_rad = np.arctan2(np.sqrt(contrast_defect), np.sqrt(darm_offset_power))
homodyne_angle_deg = homodyne_angle_rad*180/np.pi # degrees
print(f"homodyne_angle = {homodyne_angle_deg:0.5f} deg\n")

# using the photodetector responsivity (like R = 0.8582 A/W for 1064nm)
from scipy import constants as scc
responsivity = scc.e * (1064e-9) / (scc.c * scc.h)
total_dcpd_light = 40/responsivity  # so dcpd_sum 40mA is 46.6mW

Thu CP1 Fill

Thu Jun 13 10:10:35 2024 INFO: Fill completed in 10min 32secs

Gerardo confirmed a good fill curbside.

Calibration Sweep 1538 UTC

Ran the usual broadband and simulines sweep starting at 1538UTC.

Simulines start:

PDT: 2024-06-13 08:46:11.048813 PDT
UTC: 2024-06-13 15:46:11.048813 UTC
GPS: 1402328789.048813

Simulines end:
PDT: 2024-06-13 09:07:41.142373 PDT
UTC: 2024-06-13 16:07:41.142373 UTC
GPS: 1402330079.142373
 

Files:

024-06-13 16:07:41,052 | INFO | File written out to: /ligo/groups/cal/H1/measurements/DARMOLG_SS/DARMOLG_SS_20240
613T154612Z.hdf5
2024-06-13 16:07:41,060 | INFO | File written out to: /ligo/groups/cal/H1/measurements/PCALY2DARM_SS/PCALY2DARM_SS
_20240613T154612Z.hdf5
2024-06-13 16:07:41,066 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L1_SS/SUSETMX_L1_SS
_20240613T154612Z.hdf5
2024-06-13 16:07:41,071 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L2_SS/SUSETMX_L2_SS
_20240613T154612Z.hdf5
2024-06-13 16:07:41,076 | INFO | File written out to: /ligo/groups/cal/H1/measurements/SUSETMX_L3_SS/SUSETMX_L3_SS
_20240613T154612Z.hdf5

Ops Day Shift Start

TITLE: 06/13 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 5mph Gusts, 3mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.12 μm/s
QUICK SUMMARY: Locked for 15 hours, calm environment. Planned calibration and commissioning today from 830-1200PT.

Ops Eve Shift Summary

TITLE: 06/13 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY: Fairly quiet shift with H1 observing most of the time. H1 has now been locked for 8.5 hours.

• 23:28 - Started observing
• 02:07 - SQZ dropped out, ran SQZ angle scan
• 02:13 - Back to observing
• 03:13 - EQ mode activated from errant Picket Fence trigger
  • 03:23 - SEI back to CALM
• 04:04 - EQ mode activated from errant Picket Fence trigger again
  • 04:14 - SEI back to CALM

LOG:

No log for this shift.

 

Script to Get Optical Gain for a given GPS time in mA/pm

I was asked what needs to be done to convert kappa c into real physical units [mA/pm]. 

KappaC is a dimensionless number that represents the current optical gain as a fraction of what it was at some point in the past. In O4 that time corresponds to when the front end calibration was last updated (or 'exported'). You can see a list of calibration reports that have been exported to the front end on the H1 cal page. The entries with the 'exported' tag were used to update the front end and are used as reference for KappaC afterwards until the front end is updated once again. 

Since the meaning of KappaC=1 changes over time, you cannot easily trend the KappaC channel over long periods of time to compare optical gain values (yet*). You have to be sure to look at the most recently exported report and look up the optical gain (shown on the first page of the report PDF and in the enclosed pydarm_H1.ini file as "coupled_cavity_optical_gain). 

Moreover, the optical gain is reported in [DARM_ERR counts/m], not in physical units. To convert to mA/m (or mA/pm) we need to take the transfer function OMC-DCPD_SUM_OUT/DARM_IN1 [mA/ct]. However, this TF can change from lock to lock (see LHO:76000 for some discussion of this). So, given a particular GPS time, if you want to convert KappaC to mA/m you need to get the latest exported report to figure out what KappaC is in DARM_ERR cts/m, measure the OMC-DCPD_SUM_OUT/DARM_IN1 [mA/cts] transfer function (this is pretty flat so really you can condense this to a single number instead of a frequency dependent array) and multiply them. 

Ultimately, you end up with the following conversion:

KappaC * Opt gain [DARM_ERR cts/m] * OMC-DCPD_SUM_OUT/DARM_IN1 [mA/cts] = Opt gain [mA/m]


I've written a script that does this. It takes a single argument: the time at which to evaluate the optical gain. It uses the functionality I set up for a component of the noise budget (first mentioned in LHO:76000).

On gitlab the script lives at https://git.ligo.org/louis.dartez/pydarm-utils/-/blob/4018924870892f1f3ecd2fb7281e47f5df2a3f29/scripts/optical_gain.py. 

On the workstation, it currently lives at /ligo/home/louis.dartez/repos/pydarm-utils/scripts/optical_gain.py

To run the script:
  1.) activate the pydarm-utils environment: conda activate /ligo/home/louis.dartez/conda/pydarm-utils
  2.) run python /ligo/home/louis.dartez/repos/pydarm-utils/scripts/optical_gain.py TIME, where TIME is either a GPS time or a date string (use the -h option for formatting)

It will download 10 minutes of data starting at the provided time so it may take a short while.

Here is what the output should look like:

(/ligo/home/louis.dartez/conda/pydarm-utils) louis.dartez@cdsws22: python optical_gain.py 1397102112.6
Using reference report: 20240330T211519Z
Reference optical gain [DARM_ERR cts/m]: 3438377.6611055154
________________________________________________________________________________
[Memory] Calling pydarm_utils.io.gwpy_utils.get_data...
get_data([ 'H1:OMC-DCPD_SUM_OUT_DQ',
  'H1:LSC-DARM1_IN1_DQ',
  'H1:CAL-CS_TDEP_KAPPA_C_OUTPUT'], 
1397102112.6, 1397102712.6)
Opening new connection to nds.ligo-wa.caltech.edu... connected
    [nds.ligo-wa.caltech.edu] set ALLOW_DATA_ON_TAPE='True'
Checking channels list against NDS2 database... done
Downloading data: |█████████████████████████████████████████████████████████████| 601.0/601.0 (100%) ETA 00:00 _________________________________________________________get_data - 9.4s, 0.2min
KappaC: 1.0068259239196777
Optical gain [DARM_ERR cts/m]: 3461847.765427341
DARM_IN1/OMC-DCPD_SUM_OUT [DARM_ERR cts/mA]: 4.0557094393989246e-07
optical gain [mA/pm]: 8.535739103490618

Ops Eve Mid Shift Report

State of H1: Observing at 156Mpc and locked for 4 hours.

[SQZ] SQZ dropped out at 02:07 UTC, but Guardians were able to bring everything back on their own. After that, since H1 was already out of observing, I ran SQZ_MANAGER through SCAN_SQZANG since it had been noted earlier that SQZ could be better. I saw marginal improvements in DARM and range (only about 1-2Mpc), and H1 resumed observing at 02:13 UTC.

[SEI] H1 entered earthquake mode at 03:13 UTC suddenly from a Picket Fence network peak. I noticed the US.HWUT.00.BHZ station channel was highlighted in orange and the trend was drifting around in a non-real ground motion-like way, so I expect this to be a false alarm trigger as no on-site ground motion sensors saw any sudden motion. Seismic configuration went back to CALM 10 minutes later at 03:23 UTC.

Drivealign L2L gain script using kappa_tst

SheilaD, ThomasS, FranciscoL

Wrote a script to change

H1:SUS-ETMX_L3_DRIVEALIGN_L2L_GAIN
H1:CAL-CS_DARM_FE_ETMX_L3_DRIVEALIGN_L2L_GAIN

using the mean of the last 30 minutes of H1:CAL-CS_TDEP_KAPPA_TST_OUTPUT. This script will be tested before making calibration measurements, next Thursday (manifest a locked IFO).

The reason we are changing the gains is because we want to maintain the DARM open loop the same, and SRCL and MICH feedforward stable. We use KAPPA_TST because it is a monitor of how much the gains are changing - it should be 1, ideally.

The script filters the data where KAPPA_TST does not change for more than 20 seconds - see drivealign_kappa_tst_1401031920-1401044520.pdf - to avoid weighting the mean, and changes the gains with respect to the percentage that KAPPA_TST is from 1. The attached plots were used to test the script at different gps times. "drivealign_allchannels_*.pdf" plots the retreived channels from gwpy.  "drivealign_kappa_tst*.pdf" plots the results from the filtering process. The top plot is subtracting the values of KAPPA_TST, if the difference is zero it will start filtering (after 20 seconds). The two bottom-left figures show KAPPA_TST, one (top) without filtering and the other one (bottom) filtering the data. The bottom left are histograms taking (top) all the data, and (bottom) the filtered data. The script has arguments to run without plotting, or without changing the values. The output of the script that produced the attached plots is saved on terminal.txt. The script is currently in: /ligo/home/francisco.llamas/commissioning/KappaToDrivealign.py

April 22nd Output Arm Shift: Check on VAC trends and OFI tempurature

Following on from Sheila's alog 77427, checked on VAC trends and OFI temperature around April 22nd.

I checked (maybe a repeat of someone else) that there were no vacuum spikes during the locks when Kappa_C dropped or the locklosses afterwards. Plot of Kappa_ C with VAC channels attached.

Looking at the OFI TEC readbacks during that time, they were significantly noisier than usual during Tuesday maintenance after the 5% optical gain drop, before out alignment shift.  Noisy between 6:30am and 4pm. This is before any Tuesday maintenance 77363 or injections start. Plot attached, including zoom out and zoom in. It also happened the May 28th to May 30th.

Ops Day Shift End

TITLE: 06/12 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: Locked most of the shift then a lockloss with a suspicious ETMX signal  just before lockloss ended a 18 hour lock. We just got back to low noise again.

Relocking:

DRMI, PRMI, and MICH wouldn't lock with poor alignment, so I ran an initial alignment, all automatic. After initial alignment it went up to PREP_DC_READOUT_TRANSITION and then ran into the same issue Tony saw last night (alog78383). Ryan and I discussed a way to fix this in ISC_LOCK and he will make a change to remove ISC_LOCK's requesting of OMC_LOCK to Down too early.

LOG:

• 2134 Lock loss ending a 18 hour lock
• 2328 Observing

Ops Eve Shift Start

TITLE: 06/12 Eve Shift: 2300-0800 UTC (1600-0100 PST), all times posted in UTC
STATE of H1: Lock Acquisition
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 9mph Gusts, 6mph 5min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.14 μm/s
QUICK SUMMARY: H1 is in the process of relocking and currently up to PREP_DC_READOUT_TRANSITION. We ran into the issue with the OMC DCPDs not having the same gains after the whitening change again, so TJ and I are looking into a fix.

• Wind is low and microseism is trending down
• All other systems nominal

Spot position measurements on SRC optics - summary from April-June

Sheila and Keita have double-checked the sign convention of what beam positions mean given some A2L gain on an optic.  Since we have had some errors in the past few weeks, I'm summarizing their findings in this alog (and will link to this alog from the 3 measurements we have over the last few weeks).

• P2L gains that are positive mean beam is below center of optic (all optics)
• Y2L gains that are positive on SR3 mean beam is on the -X side of SR3
• Y2L gains that are positive on SR2 mean beam is on the +X side of SR2
• Y2L gains that are positive on SRM mean beam is on the -X side of SRM

Here is a summary table, in units of A2L gain:

	alog 77443, 26 Apr 2024	alog 78119, 29 May 2024	alog 78283, 6 June 2024
SR2 P2L gain	+5.5	-1.0	+8.0
SR2 Y2L gain	-4.5	+0.3	+1.5
SRM P2L gain	-3.4	-5.5	-1.0
SRM Y2L gain	+3.6	+1.85	+6.0

Here is that data translated into inferred position on the SRC optics, in mm:

	26 Apr 2024	29 May 2024	6 June 2024
SR2 Pit position [mm]	11.1 mm below center	2.0 mm above center	16.1 mm below center
SR2 Yaw position [mm]	9.1 mm -X of center	0.6 mm +X of center	3.0 mm +X of center
SRM Pit position [mm]	6.8 mm above center	11.1 mm above center	2.0 mm above center
SRM Yaw position [mm]	7.2 mm -X of center	3.7 mm -X of center	12.1 mm -X of center

 

 

Ran A2L scripts to reduce A2L coupling

Jennie W, Sheila, TJ

 

This is done to reduce the coupling we get to length from having off-centre spot positions on the mirrors.

The script can be found in userapps/isc/common/scripts/decoup/a2l_min_generic_LHO.py .

See the steps the script runs in the bottom two plots and the reponse of the ADS demodulated signals in the top plots.

I ran ETMX P and Y first by calling the script with

python a2l_min_generic_LHO ETMX BOTH

changed P and Y

H1:SUS-ETMX_L2_DRIVEALIGN_P2L_SPOT_GAIN => 3.22

H1:SUS-ETMX_L2_DRIVEALIGN_Y2L_SPOT_GAIN => 4.99

 

ETMY

both P and Y changed

H1:SUS-ETMY_L2_DRIVEALIGN_P2L_SPOT_GAIN => 4.3

H1:SUS-ETMY_L2_DRIVEALIGN_Y2L_SPOT_GAIN => 0.92

 

ITMX

both P and Y changed

H1:SUS-ITMX_L2_DRIVEALIGN_P2L_SPOT_GAIN => -0.99

H1:SUS-ITMX_L2_DRIVEALIGN_Y2L_SPOT_GAIN => 2.88

 

ITMY

H1:SUS-ITMY_L2_DRIVEALIGN_P2L_SPOT_GAIN => -0.36

H1:SUS-ITMY_L2_DRIVEALIGN_Y2L_SPOT_GAIN => -2.5
 

16:35:52 UTC all A2L gains set and script finished.

 

pressure spikes and HAM6 powers

Keita, Sheila,Robert, TJ, Jennie, Corey, Tony

Dave and Gerardo alerted us that there have been vacuum spikes after locklosses in HAM6 yesterday.  We are looking at what circulating powers were and what the lockloss transient was at the time of locklosses that caused and didn't cause a vacuum spike in HAM6.  Here is a comparison table:

time	AS_C peak	POP A LF	which alignment	spike?
6/7 1:12:35	0.938*10 = 9.378	5505	bad	3.6e-8
6/7 3:04:08	1.35*60 = 81	26739	bad	4.28e-8
6/7 03:51:29	1.05*60 = 63	27032	bad	1.5e-7
6/7 23:15:54 UTC	0.342*2 =0.684	1109	good	no
6/7 20:54 UTC	1.58*2= 3.16	651	good, PRG was tanking	no

In the bad alignment, the beam was clipped on it's way to AS_C, so that diode wasn't catching all the power it would have in the good alignment.  AS_A and AS_B saturate at the time of locklosses. 

The spike in vacuum pressure was higher with each successive lockloss, although the power on AS_C was largest in the second one.