DQ Shifters: Riley McNeil and Emil Lofquist-Fabris.

• Daily observing duty cycle: 57.91%, 38.96%, 38.57%, 51.84%, 53.67%, 89.90%, 55.83%. Week average: 55.24% Observing.

• This week was plagued by earthquakes, most notably the 8.8 magnitude earthquake from Russia and its subsequent aftershocks.

  • These really hindered the duty cycle of the detector.

  • The elevated ground motion in the earthquake band appears to be related to light scattering just above 20 Hz.

• BNS range was consistently around 150-155 Mpc throughout the week, with 1 exception being on Sunday, when the detector ran without the squeezer for 2 and a half hours, dropping the range by about 15 Mpc.

• There were also multiple days where the SQZ had issues staying locked, causing the detector to drop out of observing.

• Throughout the shift there has been recurring glitching/noise in the 20-40 Hz range, seen both in the glitch and strain plots. However, they were less significant in the last two days.

  • This has been seen in previous shifts, however relatively inconsistently.

• There was a recurring spike in noise in the H1 Y-manifold beam tube motion [X] at the exact same time every day this week (right after 17:00)

• For the first 4 days of the shift, there was a recurring noise from ~11:00-13:00 in the corner station accelerometers (all degrees of freedom), however starting Friday it stopped showing up.

• There was a low chi-squared PyCBC trigger that appears to be a blip, with the new SNR being the same as its original SNR on August 2.

See the full report here: https://wiki.ligo.org/DetChar/DataQuality/DQShiftLHO20250728

19:50 UTC

While I was trying to damp the highest modes, the pair around 1008 on ETMX (newish modes that were discovered in 2023 alog68650) which have been above 10^-16 on DARM I noticed that the other pair from ETMY (16 & 17) were not being monitored. I went into SUSPROC and unmonitored FM1, and the gain for the BL and RMSLP banks for EY 16 & 17, I turned on FM1 then ramped up the gains  starting with BL then RMSLP, then I accepted and remonitored them all.

State of H1: Observing at 150Mpc

Quiet morning with H1 staying locked throughout; current lock stretch is almost up to 21 hours. There was one brief drop from observing at 15:34 UTC when the SQZ PMC unlocked, but everything recovered automatically and H1 resumed observing a few minutes later.

Oli, Ivey, Edgard.

We used Oli's measurements from [LHO: 86204] to do an OSEM calibration for the PR3 M1 OSEMs. Here are the outputs of the calibration script.
_______________________________________

OSEM calibration of H1:SUS-PR3
Stage: M1
2025-08-05_1700 (UTC).

The suggested (calibrated) M1 OSEMINF gains are
(new T1) = 1.770 * (old T1) = 2.055
(new T2) = 1.547 * (old T2) = 1.544
(new T3) = 1.443 * (old T3) = 1.511
(new LF) = 1.590 * (old LF) = 1.862
(new RT) = 1.774 * (old RT) = 2.063
(new SD) = 1.543 * (old SD) = 1.639

To compensate for the OSEM gain changes, we estimate that the H1:SUS-PR3_M1_DAMP loops must be changed by factors of:
L gain = 0.596 * (old L gain)
T gain = 0.648 * (old T gain)
V gain = 0.617 * (old V gain)
R gain = 0.617 * (old R gain)
P gain = 0.670 * (old P gain)
Y gain = 0.596 * (old Y gain)

The calibration will change the apparent alignment of the suspension as seen by the at the M1 OSEMs
NOTE: The actual alignment of the suspension will NOT change as a result of the calibration process

The changes are computed as (osem2eul) * gain * inv(osem2eul).
Using the alignments from 2025-08-05_1700 (UTC) as a reference, the new apparent alingments are:

DOF        Previous value       New value            Apparent change
---------------------------------------------------------------------------------
L          -57.1 um             -33.6 um               +23.5 um
T          -101.3 um            -65.6 um               +35.7 um
V           62.4 um              36.6 um               -25.8 um
R           433.5 urad           225.7 urad          -207.8 urad
P          -631.8 urad          -406.5 urad          +225.2 urad
Y          -166.7 urad          -76.1 urad           +90.5 urad

We have estimated a OSEM calibration of H1 PR3 M1 using HAM2 ST1 drives from 2025-05-21_0000 (UTC).
We fit the response M1_DAMP/HAM2_SUSPOINT between 5 and 15 Hz to get a calibration in [OSEM m]/[GS13 m]

This message was generated automatically by OSEM_calibration_SR3.py on 2025-08-06 01:07:57.985744+00:00 UTC

%%%%%%%%%%%%%%%%%%%%%%%%%%%%

EXTRA INFORMATION

The H1:SUS-PR3_M1_OSEMINF gains at the time of measurement were:
(old) T1: 1.161
(old) T2: 0.998
(old) T3: 1.047
(old) LF: 1.171
(old) RT: 1.163
(old) SD: 1.062

The matrix to convert from the old Euler dofs to the (calibrated) new Euler dofs is:

+0.596    -0.0    +0.0    -0.0    +0.0    -0.003
+0.0    +0.648    -0.0    +0.0    +0.0    -0.0
-0.0    +0.0    +0.617    -0.004    +0.001    +0.0
+0.0    +0.0    -0.748    +0.617    -0.007    -0.0
+0.0    +0.0    +0.517    -0.036    +0.67    -0.0
-0.407    +0.0    -0.0    +0.0    -0.0    +0.596

The matrix is used as (M) * (old EUL dof) = (new EUL dof)
The dof ordering is ('L', 'T', 'V', 'R', 'P', 'Y')

FAMIS 26579

pH of PSL chiller water was measured to be between 10.0 and 10.5 according to the color of the test strip.

Wed Aug 06 10:06:40 2025 INFO: Fill completed in 6min 37secs

Gerardo confirmed a good fill curbside.

TITLE: 08/06 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 8mph Gusts, 4mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY: H1 has been locked and observing for 16 hours with some slight variations in range overnight as a few earthquakes rolled through. Planning for a quiet day of observing.

• Wind low, microseism still low but on the rise
• All other systems nominal

TITLE: 08/06 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY:

IFO is in NLN and OBSERVING since 22:22 UTC (6 hr 30 min lock!)

Extremely uneventful shift where we stayed locked the entire time. Range was somewhat low at the start of the lock but picked up and stabilized ~2 hours in.

Temps have effectively stabilized since the drill.

PSL dust was high but this seems to be wind driven and going down. Counts have been higher in last 3 days as well so likely not a cause for concern.

LOG:

The SUS-R6 field rack for SUS ITMY, BS, and the ESD Driver was moved a few inches towards BSC3. This was to clear for the installation of the BSC2 platform.

On July 28, Sheila and I increased the ESD bias, report in 86027. We noticed that despite rescaling the drivealign gain to match, there was a frequency-dependent change in the response function.

I used data from the simulines measurement on 7/19 (nominal bias time) and on 7/31 (double bias time) to make some comparisons. For reference, the calibration model we are currently using was generated from the 7/19 report.

The four plots attached show the ratio of the double bias measurement over the nominal bias measurement for the DARM loop suppression, response function, sensing function, and L3 actuation function.

The L3 actuation function is unchanged, indicating that we have appropriately adjusted the drivealign gain to compensate for the bias change.

The DARM loop suppression function (1/1+G) shows a frequency dependent change, which is expected.

The sensing function (C) shows some frequency dependent change. It's unclear if this is due to the change in bias, or unrelated.

The response function change (1+G /C) follows the change in both the loop suppression and sensing together.

I think a good follow up measurement is to rerun simulines with multiple ESD biases and corrected drivealign gains.

TITLE: 08/05 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: Relatively straightforward maintenance day where we were able to get back to observing before 1pm local time before a fire alarm caused a lockloss. Relocking was a bit of a struggle with DRMI taking a long time, but after running another initial alignment, H1 relocked without issue on its own. H1 has been locked and observing for just over an hour.
LOG:

• 14:54 - Lockloss during charge measurements - alog86196
  • Start of maintenance period; SEI sensor correction OFF
• 18:05 - Many maintenance tasks finished, going to try and start alignment
  • SEI sensor correction ON
  • Having to pause before INPUT_ALIGN for SR3 measurements to finish
• 18:56 - Initial alignment finished, starting lock acquisition
• 19:50 - Observing; fully automatic acquisition
• 20:00 - Lockloss from fire alarm - alog86206
• 21:14 - Starting lock acquisition
  • 21:12 - Locking has been frustrating with several low-state locklosses and DRMI not locking despite good flashes; starting initial alignment
  • 21:29 - Alignment finished
• 22:22 - Observing; fully automatic acquisiton

TITLE: 08/05 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 146Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 14mph Gusts, 7mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.12 μm/s
QUICK SUMMARY:

IFO is in NLN and OBSERVING as of 22:22 UTC

Only handoff details are that maintenance was light with a fire drill taking place:

• VAC work today involved pressure in an emergency pump going down, which should continue to go down since it's stil running post-maintenance. Channel: H0:VAC-MX_X1_PT343B_PRESS_TORR. Will continue monitoring.
• The fire drill turns off air handlers temporarily so the LVEA and VEA temps are somewhat all over the place but should be returning to nominal. Continuing to monitor.

I posted LHO:81917 regarding the calibrated ASC coupling functions. At the time, my results seemed wildly large and I was certain I had made some calibration error somewhere, and indeed I had. Lee reached out last week since he is working on something similar for his optimal controls work, see LLO:77901. These are the calibration errors I made:

• my old calibration for PUM: 20 V /2**20 ct [DAC] * 0.268 mA / V [drive strength] * 0.0309 N / A [force coeff] * 70.7 mm [lever arm]
  • the bolded term is technically correct because we do have a 20 bit DAC, however, there is a sneaky factor of 4 gain filter in the coil output filters bank, which was added to avoid everything changing by a factor of 4 when the DACs were upgraded from 18 bit to 20 bit
• There is an additional euler to osem gain value of 3.5355, and factor of 4 for four coils

The full counts of drive to Nm of torque conversion factor is therefore: (20 / 2**20) * 0.268e-3 * 0.0309 * 70.7e-3 * 4 * 3.5355 * 4 = 6.317e-10 Nm/ct

Lee also pointed out instead of using the modeled free suspension plant, I should be using the radiation pressure modified plant. This is correct, however for the purposes of calibrating the coupling function the effect is mostly the same, since we know that the rad/Nm transfer function is the same at 10 Hz within a few percent for zero power and high power.

However, for completeness, and because it matters for other calibrations, I did this instead:

• Gabriele fitted HARD loop OLGs to determine the hard plants at high power in 77857 and 71848. These fits are in counts, so they need to be scaled to real units
• Using the same modeled free plants, in T2300299, I scaled the high power plant to the modeled plant at 20 Hz
• I used this scaled high power plant to calibrate the m (DARM)/Nm (ASC) coupling function to m (DARM)/ rad (ASC)

The end result is much more sensible, resulting in a coupling function around 30 Hz that is about 1 mm/rad for both pitch and yaw. This is still "high" in the sense that Matt and Lisa assumed a coupling on the order of 0.1 mm/rad in T0900511.

I went a step further to check the linearity of the coupling. I measured the transfer function of ASC to DARM during the noise budget injection times. However, the noise budget is usually calculated with an excess power projection, so we have both quiet and injection times taken. Using the same calibration method, I compare the excess power coupling function with the linear transfer function coupling function. They appear to be nearly the same, showing that the ASC coupling is dominated by linear behavior.

Functionality test for the corner station turbo pumps, see notes below:

Output mode cleaner tube turbo station;
Scroll pump hours: 7282.4
Turbo pump hours: 7303
Crash bearing life is at 100%

X beam manifold turbo station;
Scroll pump hours: 3384.8
Turbo pump hours: 3388
Crash bearing life is at 100%

Y beam manifold turbo station;
Scroll pump hours: 4155.4
Turbo pump hours: 2823
Crash bearing life is at 100%

FAMIS tasks 31338, 31330 and 31346.

Jennie W, Sheila D

I have been updating my mode-matching calculations for the output chain of the interferometer to include the measurements we took where we heated up and cooled down SR3 (alog #84432), doing a single bounce measurement of the interferometer in each state.

Making a grid of possible values for the q parameter just before OM2 (8.8cm before, as this is the refernce I used when I was looking at single bounce measurements with hot OM2)we get the blue dots shown in the first image. If we assume that SR3 when heated has a curvature of 36.0087m, as calculated in alog #86184, then we can work out an ABCD matrix from just before SR3 to just before OM2 for both cases (SR3 cold and SR3 hot).

The beam parameter is a function of the distance to the waist  z - z₀ and the Rayleigh range z_R.

q_in = z - z₀ + jz_R

q_in = [ q_in

            1]

F_SR3 M q_in = q_out          when F is the transfer matrix of the SR3 in its cold state, and M is the transfer matrix after SR3 to the point at which we get the beam parameter q_out (8.8 cm before OM2).

q_in = M ^-1F_SR3 ^-1 q_out 

F_SR3,hot M q_in = q_out,hot when F_SR3,hot is the transfer matrix of the SR3 in its hot state and q_out,hot is the beam parameter 8.8cm before OM2 for this case.

If we substitute in the equation for q_in we can get an expression for q_out,hot:

q_out,hot  = F_SR3,hot M M ^-1 F_SR3 ^-1 q_out

In the first image the red dots are the possible q_out,hot values obtained from my grid of q_out values given in blue. The other colored dots are possible q values that are consistent with single bounce measurements while changing the heating of the SR3 (see alog #85988 for details) and OM2 (see alog #84255 for details).

The second plot shows arrows which start at all the grid points/measurements for the cold state, and end at the grid points/measurements when SR3 is heated.

WP 12696
ECR E2400330
Drawing D0901284-v5
Drawing D1900217-v3
Modified List T2500232

The following SUS SAT Amps were upgraded per ECR E2400330. Modification improves the whitening stage to reduce ADC noise from 0.05 to 10 Hz.

F. Clara, J. Kissel, O. Patane

TITLE: 08/05 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 12mph Gusts, 6mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.09 μm/s
QUICK SUMMARY: H1 has been locked for 17 hours, but looks like there were three brief drops from observing between 11:33 and 11:40 UTC (I'm assuming SQZ-related, but will look into it). Magnetic injections are running and in-lock charge measurements will happen right after before maintenance begins at 15:00 UTC.

• Wind and ground motion low
• All other systems nominal

We have many peaks below 40 Hz that couple, at least partly, through input beam jitter. Last summer Sam and Genevieve determined that a wide variety of site equipment produced these peaks, including the office area air handler, mini-splits in the CER, and chiller compressors for the main HVAC (LIGO-G2402140).  The figure shows that there is coherence between DARM and the IMC WFS that might be used to clean these low frequency peaks, but that they are currently not being cleaned.

Eventually, we would rather not have peaks that need cleaning, but instead, reduce the source vibration and/or the vibration coupling to DARM. I think that the best plan is to reduce the source vibration of the largest peaks, but to mainly focus on reducing the coupling, because many of these peaks are just 2-5 times the vibration background at the coupling sites, so even eliminating the vibration of the sources will not be enough to get us to our design sensitivity.

The coupling of relatively low amplitude vibrations at low frequencies seems to be associated with coupling resonances. For example, when one of the frequencies of the office area air handler drifted into the 35Hz peak frequency of one of these coupling resonances, the peak in DARM was huge, but was greatly reduced by changing the operation frequency of the air handler (82986).  Ill try to map out these low frequency coupling resonances during commissioning periods as a step in understanding their cause.  But for now, it would be nice to see how much we can reduce the peaks with cleaning.