I was able to get some more measurements done for the PRM and SRM estimators, so I'll note them and then summarize the current measurement filenames because there's a lot (previous measurements taken 87801 and 87950)

PRM
DAMP Y gain @ 20%
I was able to finish taking the final few DAMP Y @ 20% gain for H1SUSPRM M1 to M1. 

Settings
- PRM aligned
- DAMP Y gain to 20% (L and P gains nominal)
- CD state to 1
- M1 TEST bank gains all at 1 (nominally P and Y have a gain other than 1)
Measurements
2025-11-11_1700_H1SUSPRM_M1toM1_CDState1_M1YawDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml r12789
    - I took the measurements for V, R, P, and Y today since Jeff had taken L and T a couple weeks ago for this configuration
    - To try and lessen confusion, I changed date/time of all M1 to M1 PRM DAMP Y gain @ 20% measurements to 2025-11-11_1700 so they're all together. This means the M1 to M1 L and T measurements from a couple weeks ago now have this as the date/time

SRM
DAMP {L,P,Y} gain at 20%
I took HAM5 SUSPOINT to SRM M1 measurements

Settings
- SRM aligned
- DAMP {L,P,Y} gain to 20%
- CD state to 1
Measurements
2025-11-11_1630_H1ISIHAM5_ST1_SRMSusPoint_M1LPYDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml r12790
    - P and Y don't have very good coherence, but I ran out of time to try larger gains

Big measurement list:
PRM measurements:
DAMP gain LPY @ 20% (-0.1)
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/
    SUSPOINT to M1
    Common/Data/2025-11-04_1800_H1ISIHAM2_ST1_PRMSusPoint_M1LPYDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
    M1 to M1
    SAGM1/Data/2025-10-28_H1SUSPRM_M1toM1_CDState1_M1LPYDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
    M2 to M1
    SAGM2/Data/2025-10-28_H1SUSPRM_M2toM1_CDState2_M1LPYDampingGain0p1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
    M3 to M1
    SAGM3/Data/2025-10-28_H1SUSPRM_M3toM1_CDState2_M1LPYDampingGain0p1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml

DAMP gain Y @ 20% (-0.1)
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/
    SUSPOINT to M1
    Common/Data/2025-11-04_1930_H1ISIHAM2_ST1_PRMSusPoint_M1YawDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
    M1 to M1
    SAGM1/Data/2025-11-11_1700_H1SUSPRM_M1toM1_CDState1_M1YawDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml
    M2 to M1
    SAGM2/Data/2025-10-28_H1SUSPRM_M2toM1_CDState2_M1YawDampingGain0p1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml
    M3 to M1
    SAGM3/Data/2025-10-28_H1SUSPRM_M3toM1_CDState2_M1YawDampingGain0p1_WhiteNoise_{L,P,Y}_0p02to50Hz.xml

SRM (so far)
DAMP gain LPY @ 20% (-0.1)
/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/SRM/
    SUSPOINT to M1
    Common/Data/2025-11-11_1630_H1ISIHAM5_ST1_SRMSusPoint_M1LPYDampingGain0p1_WhiteNoise_{L,T,V,R,P,Y}_0p02to50Hz.xml

[Jenne, Alicia, Joan-Rene, with suggestions from Sheila]

Today we tested using ETMY to transition the ETMX ESD, rather than the usual locking procedure of ITMX.  I had checked on the guardian code for this last week, alog 87997.  It worked!  The first time we tried transitionining back to ETMX, we lost lock, but the second time that also worked.  We are currently locked at NLN and observing, having gotten here using ETMY and not any stages of ITMX for the ESD transition. This means that we're ready to try grounding the ITM ESDs, to see if that helps reduce the combs that Alicia and Joan-Rene have been investigating. 

• The first time we tried locking, we went through the state LOWNOISE_ESD_ETMY by hand, so that we could transition ETMX -> ETMY slowly and measure the DARM loop along the way.  
  • We measured the DARM open loop gain before any transitioning, then after 25%, after 50%, after 75%, and after we were fully on ETMY.  See attached plot with the measurements labeled on the right side with percent of actuation on ETMY.
  • When we tried to transition back ETMY -> ETMX 25% of the way, (doing the state LOWNOISE_ESD_ETMX by hand), we lost lock.
    • After looking through the settings, it could be that the ETMX L1 Lock L filter bank wasn't set correctly (FM2 not on), even though I see that in my guardian shell I told it to turn on. 
    • Or, as Sheila points out to us, it could be that this transition back to ETMX is rather delicate, and we're going from using 2 stages of the temporary (ETMY) suspension to 3 stages on low noise ETMX, and we just can't do that part way.  
• The second time we tried locking, we let the guardian go through LOWNOISE_ESD_ETMY, which was successful.  We also checked that the ETMX L1 LOCK L filter bank was set up correctly. Since we were worried about going partially back to ETMX being delicate, we just ran the LOWNOISE_ESD_ETMX state to ramp all the way back to ETMX at once, and that was also successful. 
  • It turns out that I had forgotten that we'd need to disable the ETMY L3 Length actuation after we were done using it, since ETMY is used as part of our LSC FF actuation path, and that signal is only supposed to go to L2.  We had a funny bump in the DARM spectrum, and also some SDF diffs on ETMY that helped us find that easily.  
  • I have added (but not tested) a few lines in LOWNOISE_ESD_ETMX to reset the ETMY L3 settings to match the Observe.snap SDF, which should also fix the lump from improper feedforwarding. 

As of now, the guardian is set to acquire lock still using the nominal ITMX ESD.  So, before we ground the ITM ESDs we'll need to modify the weights in the guardian path, to make it so that the nominal path uses the ETMY and not ITMX.

Gerardo, Jordan, Travis

Today, we finished the installation of the replacement purge air piping at EY.  The system still needs to be tested for gross leaks, new filter elements on the supply line installed, an additional support added to the mechanical room side of the purge piping, and the new compressor and purge line validated via FTIR testing.  We plan to finish these installations and tests in the next week or two.  

20:00 UTC I swept the LVEA, I didn't see anything of note.

M. Todd, Kar Meng, S. Dwyer

We took more OMC scans today with OM2 hot. We measured a quadratic mismatch of about 6.8%, but the HG10 peak (misalignment) has enough power that I think this could be an underestimate by a percent or so. 

We struggled a lot to get good measurements at first, though we followed the directions I wrote last time to the letter. So I'm adding some "bewares" for future reference.

1. The OPO IR locked on 0.2 counts when last time we had a level of around 1 count. We didn't catch this right away but this was essentially locking on a 10 mode and sending that to the OMC and it was giving REALLY strange OMC scans. 

2. Once we figured this out, it ensured that we had enough power on the OMC QPDs and the OMA/OMB WFS-DC to get a pretty good centering. Once we ran the OMC scan, we found much better data compared to last week, though we notice here that the 10 peak still has about 50% of the power as the 20 peak (which we're after). This means that the estimate of quadratic mismatch using the P00/(P00+P20+P02) is probably underestimating the mismatch a bit. Note, using the cursors to calculate the power in the peaks means it is just the 00peak/(00peak+20peak) because the power in the 20peak contains both HG20 and HG02 as the OMC has very little astigmatism.

Tue Nov 11 10:04:05 2025 INFO: Fill completed in 4min 2secs

M. Todd

Summary: I do not think the ISS is limited by the input jitter (IMC PZT) from 1-1000 Hz. I have attached the injections I've made to the IMC PZT here. Below 1Hz I suspect the ISS is dominated by the IMC motion.

I unlocked the ifo at 2025-11-11 16:03:17 UTC so we could start maintenance Tuesday

TITLE: 11/11 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 3mph Gusts, 2mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.29 μm/s 
QUICK SUMMARY:

Currently Observing and have been Locked for over 11 hours. Today is maintenance day. It's also super foggy outside

Workstations were updated and rebooted.  This was an os packages update.  Conda packages were not updated.

TITLE: 11/11 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 153Mpc
INCOMING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 6mph Gusts, 3mph 3min avg
    Primary useism: 0.02 μm/s
    Secondary useism: 0.29 μm/s
SHIFT SUMMARY:
After a lockloss early tonight relocking was simple after an Iniital_Alignement.
H1 has been locked for 1.5 hours. everything seems like it should be running well for the rest of the night.

LOG:
No log.

02:44:29 Lockloss
ETMX_L3 Master out looks to have had a glitch about 300 ms before hand and then was the first channel to deviate at 146ms before the lockloss.
Obligitory Lockloss ndscopes attached.
 

TITLE: 11/11 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: Ibrahim
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 5mph Gusts, 2mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.30 μm/s 
QUICK SUMMARY:
H1 has been locked and Observing for 5.5 hours.
Violins, secondary microseism & the wind forecast  are all looking great! 
The range seems to have settled down too.
Looks to be a great night for Observing.
 

TITLE: 11/11 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY:

IFO is in NLN and OBSERVING as of 19:45 UTC (but locked at 19:09). 

Very well behaved IFO today with short reacquisition. Wind is still low and microseism continues to fall.

Had one LL during commissioning (lockloss alog 88043)

OFI temp is stepping once an hour for the next 4ish hours - should not interfere with relocking or anything, Alog 88046.

Additionally, there was a power glitch (not on-site but in town) that flickered lights and caused IY to saturate until power came back a few ms later. Alog 88049.

LOG:

Ibrahim, Ryan S, Tony

H1 saw a power glitch after lights flickered (Ryan S noticed NUC21 flickered) and IY SUS saturated. Dave confirms GC UPS saw the glitch.

Power has gone out (temporarily?) in-town according to friends.

Plots attached.

I noticed that in the high-frequency spectra (2000–5000 Hz) of both detectors from O4a data, there are spectral lines exactly at 2048 and 4096 Hz. They are so narrow that only the power at the exact frequency bins of 2048 Hz and 4096 Hz is significantly elevated.

This might be due to artifacts from the data-acquisition process. I searched the aLOGs for H1 and L1 but haven’t found relevant entries. Does anyone know the origin of these two lines?

Keita, Rahul

We received three mirrors (JM1, 2 and 3) for the Jitter Attenuation Cavity (JAC) from CIT and were asked to characterize these mirrors before installing them in HAM1 chamber for the upcoming vent at LHO. JM1 and JM3 optics will be used in Tip Tilt supension and JM2 optic will be on a fixed mount inside the HAM1 chamber. Given below are the details of our setup and the results after characterizing them in the optics lab.

Aim of the experiment:- (a) to measure the reflectivity of the three mirrors as a function of its Angle Of Incidence (AOI) for P polarization of the input beam (1064nm laser), (b) measure the transmission of the optics at its AOI (defined in T2400360).

Experimental setup in Optics lab:- The optical layout is shown in figure1. We used a 1W 1064 nm laser (the power was reduced to 15mW approximately using a half wave plate). A polarizing beamsplitter was used to transmit P polarization waves to the steering mirror and the S polarization waves were reflected towards beam dump. The steering mirror used over here is dichroic (reflecting 1064nm light and transmitting/rejecting spurious green light emerging from the laser towards the beam dump). We used two lens to focus the input beam - one located upstream of the steering mirror and another one downstream of the same. The optic was installed on a Siskiyou mount, which was placed on a rotational stage - as shown in the picture. Thorlabs Power meter was used to measure the input, output and transmitted beam. 

Results:-

We did coarse and fine measurement to characterize the mirrors. For coarse measurement, we started at zero degree AOI (when the input beam was reflected back towards the iris) and then rotated the optic until the output power nulled - while recording the reflected power at every 5 degree interval. 

For fine measurements we set each optic at its AOI (as defined in T2400360) and then carefully measured the input, output and transmitted power. The results are given below,

Last week (87801) Jeff took a bunch of transfer function measurements for PRM for the PRM L, P, and Y estimators. There were some he wasn't able to take:

- H1ISIHAM2 to H1SUSPRM M1 for all dofs with DAMP L, P, and Y all with 20% gain

- H1ISIHAM2 to H1SUSPRM M1 for all dofs with DAMP Y at 20% gain

- H1SUSPRM M1 to M1 for V, R, P, Y with DAMP Y at 20% gain

Today I was able to get the first two bullet points done

Measurements:

First, I made sure the SUSPOINT matrix had the correct values for driving PRM, which it did. 

First set (L P Y DAMP gain at 20%):

L, P and Y DAMP gains were set to 20% of their nominal values, so they were set to -0.1, and T, V, and R were left at their nominal -0.5 gain values. 

Measurements can be found in 

/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/Common/Data/2025-11-04_1800_H1ISIHAM2_ST1_PRMSusPoint_M1LPYDampingGain0p1_WhiteNoise_*_0p02to50Hz.xml r12766

Second set (Y DAMP gain at 20%):

After those measurements were taken, I set the L and P DAMP gains back to their nominal values of -0.5 and took another set of SUSPOINT measurements with only the Y gain at 20%.

Those measurements can be found in 

/ligo/svncommon/SusSVN/sus/trunk/HSTS/H1/PRM/Common/Data/2025-11-04_1930_H1ISIHAM2_ST1_PRMSusPoint_M1YawDampingGain0p1_WhiteNoise_*_0p02to50Hz.xml r12767

I ran out of time and wasn't able to finish the four M1 to M1 dofs that were left for the reduced Y damping, so we'll have to get those next week.

I also wasn't able to get in any measurements for SRM, but that's okay since we're not in a rush.

J. Kissel

Gathered H1SUSPRM M3, M2, and M1 Drive to M1 Response TFs to inform the "drive" models for a future H1SUSPRM estimator. I'll post the locations / file names in the comments. Here in the main entry, I discuss the state of the control system for H1 SUS PRM so we understand with how much salt would should take these measurements.

Executive summary :: there are some side quests we can launch -- especially on the actuation side of this suspension -- if we think that these measurements reveal "way too much cross coupling for an estimator to work." The first things I'd attack would be 
    - the frequency-dependent and scalar gain differences *between* the nominal low noise state of the coil drivers and the state we need to characterize the suspension. 
    - the very old coil balancing, which was done *without* first compensating for any frequency-dependent gain differences in the channels at the frequency used to balance the coils (see LHO:9453 for measurement technique.)

Here's the detailed summary of all the relevant things for these measurements:
    - The suspension was ALIGNED, with alignment offsets ON, with slider values (P,Y) = (-1629.783, -59.868) ["urad"] 
        :: ALIGNED is needed (rather than just DAMPED [where the alignment sliders are OFF] or MISALIGNED where extra large alignment offsets are ON; per discussion of how the alignment impacts the calibration in LHO:87102)
        :: the usual caveats about the slider calibration, which is still using the [DAC ct / "urad"] gains from LHO:4563).

    - The M1 damping loop were converted to Level 2.0 loop shaping in Jan 2023; LHO:66859, nominally designed to have an EPICs gain of -1.0. However in Aug 2023, the EPICs gains were lowered to -0.5, and have been that way for most of O4, and remain that way now. For all of these measurements, I set the L, P and Y gains to -0.1; the "20% of nominal" gain mantra we've used for the HLTS estimators. I also gathered *almost* all the measurements again with only the Y gain at -0.1, but ran out of time to complete that set for comparison. 

    - Even though it was maintenance day, when we typically turn site-wide sensor correction OFF, I manually turned ON sensor correction for ISI HAM2 to get better coherence below 1 Hz (using instructions in LHO:87790)

    - The M3 L to M3 P filter (and gain) in the M3 DRIVEALIGN frequency-dependent matrix is OFF, per LHO:87523. 

    - There are (M3 P to M3 L) = 1.7 and (M3 Y to M3 L) = 0.52 scalar gains ON in to off-diagonal elements of the M3 DRIVEALIGN matrix whose purpose is change the center of P and Y actuation to be around where the IFO's beam spot typically is.

    - There is a set of M1 L to M1 P filters, "M1L_M3P" and "invM1P_M3P," in the M1 DRIVEALIGN matrix, with a EPICs gain of -1. I think these came from LHO:42549. The measurements I took aren't impacted by this, as I drove from the M1 TEST bank which does not send excitation through the DRIVEALIGN Matrix. HOWEVER, we'll definitely need to consider this when we model the ISC drive which *does* go through the M1 DRIVEALIGN matrix.

    - All M1, M2, and M3 stages of OSEM PDs sat amp whitening filters have been upgraded with ECR E2400330's filter design, and compensated accordingly. 
        :: M1 stage LHO:85463
        :: M2 & M3 stages LHO:87103

    - All M1, M2, and M3 stages of OSEM PDs have been calibrated via the ISI GS13s, and calibrated in the ALIGNED state (LHO:87231)

    - In order to get decent coherence over the band of interest for the M3, M2, and M1 drives, I had to drive the suspension actuators in their highest range state, which is different from the state the IFO usually needs.
        :: M1 = State 1 "LP OFF" (a Triple TOP Driver)
        :: M2 = State 2 "Acq ON, LP OFF" (An ECR E1400369 Triple Acquisition Driver "TACQ" modified for an extra 10x actuation strength. Modified in Sep 2013 LHO:7630)
        :: M3 = State 2 "Acq ON, LP OFF" (An ECR E1400369 Triple Acquisition Driver "TACQ" modified for an extra 10x actuation strength. Modified in Sep 2014 LHO:13956)

        :: The nominal state for the switches are M1 = State 2 "LP ON," M2 = M3 = State 3 "ACQ OFF, LP ON."

    - No actuator channels have had any precise compensation for their coil driver's frequency response in any state.
        :: M1 state 1 channels are all compensated with (z:p) = (0.9 : 30.9996) Hz
        :: M2 state 2 channels are all compensated with (z:p) = (64.9966 : 13) Hz
        :: M3 state 2 channels are all compensated with (z:p) = (64.9966 : 13) Hz

    - There are scalar "coil balancing" non-unity magnitude gains on each of the M2 and M3 stage channels, but it's the same values that have been in play since Jan 2014 (LHO:9419; so, after the M2 TACQ driver mod, but before the M3 TACQ driver mod). There is no coil balancing gains on the M1 stage, they're all either +/- 1.0.