This errata is the SR3 version of [LHO: 87160] that dealt with PR3. 

While double-checking the PR3/SR3 OSEM calibration script, I noticed a typo on the printing output of the function that generated the logpost [LHO: 85907].

No changes need to be made because the calculated M1 OSEM calibrations and M1_DAMP gains are both correct. Plots and other visual documentation is all correct too.

However, the expected alignments posted in [LHO: 85907] were wrong, as the (old EUL) to (new EUL) transformation matrix was accidentally inverted.

I post here the corrected script output for the SR3 OSEM calibration for the sake of documentation and transparency. Note that the theoretically calculated alignment values match the observed ones for SR3 too [see attached screenshot]

_____________________________________________________

OSEM calibration of H1:SUS-SR3
Stage: M1
2025-07-22_1530 (UTC).

The suggested (calibrated) M1 OSEMINF gains are
(new T1) = 2.174 * (old T1) = 3.213
(new T2) = 1.610 * (old T2) = 1.517
(new T3) = 1.569 * (old T3) = 1.494
(new LF) = 1.331 * (old LF) = 1.733
(new RT) = 1.374 * (old RT) = 1.494
(new SD) = 1.390 * (old SD) = 1.793

To compensate for the OSEM gain changes, we estimate that the H1:SUS-SR3_M1_DAMP loops must be changed by factors of:
L gain = 0.740 * (old L gain)
T gain = 0.719 * (old T gain)
V gain = 0.545 * (old V gain)
R gain = 0.545 * (old R gain)
P gain = 0.629 * (old P gain)
Y gain = 0.740 * (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 2025-07-22_1530 (UTC) as a reference, the new apparent alingments are:

DOF        Previous value       New value            Apparent change
---------------------------------------------------------------------------------
L          -5.0 um              -7.7 um                 -2.8 um
T          -21.6 um             -30.0 um                -8.4 um
V           11.8 um              10.6 um                -1.2 um
R          -576.3 urad          -1036.9 urad         -460.6 urad
P          -266.5 urad          -447.4 urad          -180.8 urad
Y          -585.0 urad          -792.6 urad          -207.6 urad

We have estimated a OSEM calibration of H1 SR3 M1 using HAM5 ST1 drives from 2025-05-21_0000 (UTC).
We fit the response M1_DAMP/HAM5_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 2025-09-26 21:16:58.591270+00:00 UTC

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

EXTRA INFORMATION

The H1:SUS-SR3_M1_OSEMINF gains at the time of measurement were:
(old) T1: 1.478
(old) T2: 0.942
(old) T3: 0.952
(old) LF: 1.302
(old) RT: 1.087
(old) SD: 1.290

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

+1.353    +0.0    -0.0    +0.0    -0.0    +0.002
+0.0    +1.39    +0.0    -0.0    -0.0    +0.0
+0.0    +0.0    +1.882    +0.02    -0.0    -0.0
+0.0    -0.0    +4.175    +1.882    +0.007    +0.0
-0.0    -0.0    -0.454    +0.032    +1.59    +0.0
+0.27    -0.0    -0.0    +0.0    +0.0    +1.353

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

While double-checking the PR3 OSEM calibration script, I noticed a typo on the printing output of the function that generated the logpost [LHO: 86222].

No changes need to be made because the calculated M1 OSEM calibrations and M1_DAMP gains are both correct.

However, the expected alignments posted in [LHO: 86222] were wrong, as the (old EUL) to (new EUL) transformation matrix was accidentally inverted.

I post here the corrected script output for the PR3 OSEM calibration for the sake of documentation and transparency. Note that the theoretically expected alignment values are in line with the observed ones [see attached screenshot]

____

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             -97.3 um               -40.2 um
T          -101.3 um            -156.3 um              -55.0 um
V           62.4 um              106.7 um              +44.4 um
R           433.5 urad           819.6 urad          +386.1 urad
P          -631.8 urad          -981.5 urad          -349.7 urad
Y          -166.7 urad          -345.9 urad          -179.3 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 2025-09-26 20:41:09.411215+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:

+1.682    +0.0    -0.0    +0.0    -0.0    +0.007
+0.0    +1.543    +0.0    -0.0    -0.0    +0.0
+0.0    +0.0    +1.633    +0.01    -0.001    -0.0
+0.0    -0.0    +1.964    +1.633    +0.017    +0.0
-0.0    -0.0    -1.154    +0.081    +1.495    +0.0
+1.148    -0.0    -0.0    +0.0    +0.0    +1.682

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

STATE of H1: Observing at 152Mpc

• We've been locked for just under 5 hours
• The bounce mode has damped below the reference
• Secondary microseism has started to increase over the past hour
  • The range has slightly dropped over a similar timescale, the SQZ blrms look like its maybe from low frequency (RATIO_{1,2}_DB_MON, red and orange)

Fri Sep 26 10:09:31 2025 INFO: Fill completed in 9min 27secs

Gerardo confirmed a good fill curbside.

Closes FAMIS26663, last checked in alog87026

Laser Status:
    NPRO output power is 1.858W
    AMP1 output power is 70.03W
    AMP2 output power is 139.0W
    NPRO watchdog is GREEN
    AMP1 watchdog is GREEN
    AMP2 watchdog is GREEN
    PDWD watchdog is GREEN

PMC:
    It has been locked 2 days, 20 hr 56 minutes
    Reflected power = 24.91W
    Transmitted power = 104.2W
    PowerSum = 129.2W

FSS:
    It has been locked for 0 days 2 hr and 13 min
    TPD[V] = 0.5372V

ISS:
    The diffracted power is around 4.2%
    Last saturation event was 0 days 2 hours and 13 minutes ago

Possible Issues:
    PMC reflected power is high

TITLE: 09/26 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 9mph Gusts, 6mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.21 μm/s 
QUICK SUMMARY:

• We've been locked for about 10 minutes following a 12:51 UTC lockloss
  • 14:20 UTC Observing
• Local earthquake overnight from Oregon, plus high winds
   

Got notified again and since I hadn't slept yet, was still logged in with some ideas of what was causing issues.

H1 got stuck at input align and a quick looksy through the alog found this parcel of frustration from TJ's alog 86095. Using the wiki and following this, I found that indeed:

IM's did not quite restore to an aligned state post EQ so I trended back OSEMs and moved sliders:

• IM1: 
  • P: 3160 to 3140
  • Y: -680 to -681
• IM2:
  • P: 943 to 913
  • Y: -218 to -224
• IM3:
  • P: 67 to 57
  • Y: -1633 to -1630
• IM4:
  • P: -2829 to -2835
  • Y: -14 to 1

This worked! 

But as then I couldn't lock SRY, so I moved SRM a bit in order to maximize AS_A centering peaks!

This also worked!

Back to LOCKING

A 5.9 EQ from Oregon hit H1 quite violently and tripped:

HAM1 ISI, HAM2 ISI, HAM2

IM1 (M1), IM2 (M1), IM3 (M1), IM4 (M1)

MC1 (M1), MC2 (M1), MC3 (M1)

PRM (M1,2,3), PR2 (M1), SRM (M1,2,3), SR2 (M1), SR3 (M1)

FC1 (M1,2,3), FC2 (M1,3)

Along with their respective ISIs (ST1) and the QUAD ISIs (though I untripped a bit too quickly to note the exact ISIs I untripped so will append this tomorrow when I can trend without lag).

A few guardians also stalled so I unstalled them. I attached an overview of verbal trips and overview screen.

IFO is back to LOCKING and EQ is mostly passed. I've reset myself as the OWL.

TITLE: 09/26 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Wind
INCOMING OPERATOR: Ibrahim
SHIFT SUMMARY: Currently relocking and in LASER_NOISE_SUPPRESSION. One lockloss today due to the wind, and relocking has been taking a while because of the wind. We were worried about the ETMY Roll mode earlier, but it ended up coming back down on its own. Maybe we should keep an eye on it over the weekend, but it seemed like the current setting are doing okay. The ion pump is still running in the LVEA - since the lockloss was so late in the evening, there were no vacuum people on site to turn it off, but that's okay. 
LOG:

23:30 UTC Observing and Locked for over 11 hours
    00:22 GRB-Short E603710
02:27 Lockloss
    - ALSY needed help
    - Constant ALS locklosses because of high wind, so sitting in DOWN for a while

Lockloss at 2025-09-26 02:37 UTC after 14.5 locked due to high wind :( We were riding it out really well up until now 

Here is a summary of some results from the open loop gain measurements of DHARD Y and CHARD Y, and the implementation of a new CHARD P low pass:

DHARD Y

I measured the DHARD Y open loop gain, results shown here. The dark blue trace shows the original measurement, showing 17 degrees of phase margin and gain peaking of 10 dB. Looking at the loop design, there are three different boost filters applied to DHARD Y, compared here. These boosts in combination seem to be destroying all the phase of the loop. I took a measurement with the 0.9 Hz boost disengaged (FM3), which is shown in the green trace. Then, I disengaged the 0.5 Hz boost (FM4) and remeasured, shown in the red trace. This improved the phase margin to 32 degrees. This obviously resulted in less microseismic suppression. I adjusted the 0.5 Hz boost (FM4) and decided we should operate without the boost in FM3. This plot compares the original loop error signal and RMS with all three boosts (gold), the error signal and RMS without FM3 and FM4 boosts (green) and then error signal and RMS with the updated FM4 boost (red). The RMS increased 50% without both boosts on, the improved boost returns the RMS to that value. There is now more phase margin in the loop. Updated in guardian and ASC high gain script, SDFed (1,2).

CHARD Y

I measured the CHARD Y open loop gain, results shown here. The file had an old reference trace from 2023, shown in bluegreen in the reference. The gray trace shows the first measurement I made today of CHARD Y. The gain appeared to be way too low. I raised the gain to match the old reference, which was a gain increase of 6 dB. Here is a comparison of the RMS of CHARD Y from 14 hours ago (bluegreen reference) and now (red live). The microseism level is the same between these two measurements. Overall, this reduces the RMS of the loop, so I think this is a good adjustment. This is updated in the guardian and ASC high gain script, also SDFed.

CHARD P

I implemented a new CHARD P low pass filter to reduce CHARD P coupling that is apparent in coherence measurements (example).

Here is a comparison of the old controller (red) with the new controller (blue). This replaces the lowpass filter in FM8 with the filter in FM9. I also disengaged the old 200 Hz lowpass that was previously in FM10, as it wasn't doing much. SDFs (1,2). Guardian code and ASC high gain script updated.

The coherence of DARM with CHARD P has reduced, as expected, and increased for CHARD Y, also as expected. I have since created a new lowpass for CHARD Y that should reduce the coherence and is ready for testing at the next opportunity (comparison).

TITLE: 09/25 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 147Mpc
INCOMING OPERATOR: Oli
SHIFT SUMMARY: H1 has been locked the whole day so far; current lock stretch is up to almost 11.5 hours. The ETMY roll mode is slightly more rung up than it has been in the past few days, but maybe not egregiously so; Oli will keep an eye on it this evening. Other than commissioning time this morning, it's been a quiet shift.

• 15:30 - Dropped observing for calibration sweeps
• 16:00 - Calibration finished, starting commissioning
• 17:04 - GRB-Short E603626 (was not observing)
• 20:02 - Commissioning finished, resuming observing

LOG:

Today I adjusted the DHARD gain and asked Ryan to rerun the simulines measurements to see if changing the DHARD gain has any measureable effect on the sensing function. This tests possible L2A2L coupling present in the sensing function.

Based on recent OLGs of the HARD loops, I decided we could probably lower each gain by 3 dB. For DHARD P, this takes the gain from -30 to -18 and DHARD Y from -40 to -24.

We ran one simulines with DHARD P gain lowered and one with DHARD Y gain lowered. These measurements can be compared with this morning usual calibration measurement.

The results seem a bit inconclusive to me. There might be some change in the phase below 10 Hz. First I compare the three sensing measurements, then I take the ratio of each measurement with the "nominal settings" measurement.

TITLE: 09/25 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: Ryan S
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 19mph Gusts, 14mph 3min avg
    Primary useism: 0.06 μm/s
    Secondary useism: 0.16 μm/s 
QUICK SUMMARY:

Observing at 150 Mpc and have been Locked for almost 11 hours. Wind has increased recently, but shouldn't get too bad. ETMY roll mode has been slowly increasing over the past ~few hours, so I'll be keeping an eye on it.

Since maintenance will start early next Tuesday, I've updated the PEM_MAG_INJ node to start its injections at 6:00am (13:00 UTC) and the SUS_CHARGE node will start at 6:25am (13:25 UTC). These should all be finished by 6:45am (13:45 UTC).

I don't have time to analyze these for now, so I'm just dumping the pictures here.

On Tuesday Sep/23 RyanS and I went to the PSL room to do two things.

• Measure the beam size downstream of the bottom periscope mirror with two different settings. Wincam was put at the same place as the measurement on Sept/15 (alog 86949).
  • The new nominal setting where PMC receives the full power but EOM receives the reduced power (PSL-PWR_PMC_TRANS~103W, IMC-PWR_EOM~86.6W or so, and IMC-PWR_IN=2W at the time of measurement). See the 1st photo. Note that IMC-PWR_EOM calibration is known to be bad, it's only useful for making the ratio of two power levels.
  • PMC power is reduced but the EOM receives the same power as the nominal setting (PSL-PWR_PMC_TRANS~77W, IMC-PWR_EOM~86.6W or so, and IMC-PWR_IN=2W at the time of measurement). See the 2nd photo.
• Look through the EOM with a help of green flashlight to see if there's something apparently wrong, which we didn't find though we found some specks which might be far from the beam.
  • We put a 45 degree mirror on the PSL table right after the EOM and look through the EOM (i.e. the camera is downstream of EOM, looking into upstream direction). In the third photo (DSC_0776.jpg) the focus is on the output aperture of the EOM. As I shifted focus closer towards PMC, somewhere close to the input face of the crystal, two specks (maybe one is the ghost image of the other?) became visible. See DSC_0778.jpg.
  • We also tried to see the EOM from the input aperture side, which was not at all productive due to tight space. DSC_0782.jpg was the best view we got but we still couldn't even see the entire front surface of the crystal.
  • We also tested hand-holding a USB microscope but was hopeless. It might have been better with some kind of rigid structure to rest a hand/microscope on (but the space is very tight).

J. Kissel

In prep for measuring the absolute calibration PRM and SRM OSEMs, I've changed the ISI HAM2 / HAM5 suspension point drive matrices to project from the PRM and SRM suspension points rather than PR3 and SR3 what we used when calibrating those top mass OSEMs.

Here's the method for installing these matrices:

>> addpath /ligo/svncommon/SeiSVN/seismic/Common/MatlabTools/
>> load /opt/rtcds/userapps/trunk/isc/common/projections/ISI2SUS_projection_file.mat;
>> ham2 = ISI2SUSprojections.h1.prm.EUL2CART;
>> fill_matrix_values('H1:ISI-HAM2_SUSPOINT_EUL2CART',ham2)
>> ham5 = ISI2SUSprojections.h1.srm.EUL2CART;
>> fill_matrix_values('H1:ISI-HAM5_SUSPOINT_EUL2CART',ham5)

Attached are screenshots of the matrix MEDM screens themselves and the SDF accept in the OBSERVE .snap files. 
Since these are used and moved around to calibrate each of the SUS in the chamber, and it's so simple to restore if lost, I'm not bothering to save the values in the ISI's safe.snap.

Elenna Capote, Camilla Compton, Sheila Dwyer, Derek Davis

This afternoon we had a repeat of the bad low frequency noise that we have been suspecting was from filter cavity backscatter 86596.  We saw that the symptom of elevated noise in the filter cavity error signal was similar to previous incidents plot. 

We compared squeezing with and without the filter cavity, and no squeezing, and see that this noise is there when squeezing is injected no matter what the filter cavity state is.  plot and plot with mean sqz and anti squeezing. 

We repeated the fringe wrapping measurements, we saw a higher scattered amplitude when moving ZM5 than last week. (shelf is higher by 10dB). the ZM2 shelf is about the same. plot

We also did some 30 Hz excitations in ZM5 + ZM2, we can see a bilinear coupling of these but the background didn't change during this excitation. plot

Derek and Elenna looked at the glitches in DARM that showed up at the time of the noise.  Derek ran some hveto runs for times with frequency dependent squeezing and frequecy independent squeezing, and saw that filter cavity length signals are a good witness when the filter cavity is locked, when the filter cavity is not locked the giltches stay but aren't witnessed by the FC error signal. 

Camilla found that she could reproduceably make the noise go away by moving the ZM4 +5 PSAMs small amounts.  She moved the PSAMs and adjusted the alignment to get a good level of high frequency squeezing back.  She also tried to do this with alignment only. 

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')