JAC mode-matching correction from the LDWFS-measured injection beam

Using the injection beam measured with LDWFS, I computed an IO_MB lens layout that improves the JAC mode-match at 62 W from 1.8 % to ~0.1 %. 
LDWFS method and measurement results: LIGO-P2600491

Move the two injection mode-matching lenses upstream:

• IO_MB_L1: 21.3 mm (0.84")
• IO_MB_L2: 48.3 mm (1.90")

(common shift −34.8 mm sets the waist position; differential +13.5 mm sets the waist size.)

Figure: beam radius w(z) along the injection path — cavity eigenmode, injected beam, and the beam after the L1/L2 correction.

X-End Prep Work for Vent

(Travis S., Gerardo M.)

The cleanroom above BSC9 is on, 2:45 pm today.
The purge air system is on, compressor and dryer towers are on, but only in the vacuum support equipment room, the valve to deliver air to the VEA is closed.
We delivered two ISP-1000 scroll pumps and an electrical bang box, we left them inside the receiving area.

HAM7 Vent Recovery Update

(Jordan V., Travis S., Gerardo M.)
The turbo pump and SS-500 cart are off now, since HAM7 ion pump is able to maintain the chamber's vacuum pressure, and the ion pump continues to pump down the chamber, see atached plot.  So, we decided to introduce the HAM7 volume to the main vacuum envelope at the corner station.  The filter cavity tube also is part of the main vacuum envelope.
We only need to move the vacuum equipment near HAM7; SS-500 cart, two CUBE aux carts and flex hoses. The SS-500 still cabled to the turbo pump since it needs to spun down.

A quick summary of ALS diff attempts

Oli, Louis, Caroline, Sheila, Elenna, Gabriele

At the start of the day I did a check by measuring the ETMX M0 L2L transfer function and saw that with the alignment offsets ON and the R0 yaw offset of -25000 ct, we still see no evidence of rubbing in the transfer function.

Then, I locked ALS on both arms, and was able to drive tidal feedback and WFS feedback to ETMX.

Louis and I proceeded to lock ALS diff on ETMX and started troubleshooting the issues with ALS diff on ETMY.

In short, we still have no idea what the issue is. I measured a transfer function of ETMX L1 to DARM err and compared it to the same transfer function from ETMY L1. They are the same except for an overall minus sign, which is expected.

We then tried to do the sam measurement of the ETMY L3 feedback, but held in down due to an earthquake. After the earthquake, I found we could not lock ALSX and send tidal feedback to ETMX L1. This indicated rubbing again, but the transfer function showed no rubbing.

I was able to turn on the WFS control to ETMX, which drives L2 and M0, and this works fine. The problem seems to be confined to ETMX L1.

I have attached some screenshots and also SDFs that came up during the day- I had to SDF the ETMY L2 length feedback switch OFF and I SDFed the ETMX R0 yaw offset.

Fri Ops DAY Shift Summary

TITLE: 09/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Tony
SHIFT SUMMARY:

Some prep work started for a vent of EX for in-chamber work on Monday (to address ETMx rubbing which returned yesterday).

Commissioners worked on mostly ALS work to possibly allow for DRMI work next week.

HAM7 + Filter Cavity added to the main volume!

LOG:

• (all-day) beam tube enclosure patch work with manlift (randy)
• 1500-1526 JAC remote measurements (masayuki)
• 1638 Aligned Green Y-arm (ALS_YARM to INITIAL ALIGNMENT OFFLOADED)
  • Elenna will be working on X-arm (I had touched up green X-arm flashes, but I backed this out because Elenna will be working on X-arm)
• 1734-1752 dustmonitor huddle test in optics lab (ryanC)
• 1909-1947 JAC measurements (masayuki)
• 2025-2114 Opening HAM7 + Filter Cavity into the main volume & turning off HAM7 turbo (gerardo)
  • 2056 looking for gerardo
• 2052-2213 Taking pelican case to H2PSL room and loading it with CRS parts for LLO (jim)
• 2055-2116 measurements around BSC3 (jenne)
• 2119-2158 Moving equipment from LVEA to EX in prep for vent (gerardo.travis)
• 2142 M6.6 Christmas Island EQ notification
  • 2144 EQ mode activated
  • 2215 EQ mode activated
• 2151-2227 Scoping out plumbing for tcs (tj)
• 2145 EX cleanroom turned ON -and- purge air compressor + dryer tower turned ON for EX vent (gerardo)

SEI ground seismometer mass position check - Monthly

FAMIS64118

2026-09-11 16:05:55.288609

There are 21 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -2.315 [V]
ETMX T240 2 DOF Y/V = -2.182 [V]
ETMX T240 2 DOF Z/W = -1.542 [V]
ITMX T240 1 DOF X/U = -2.689 [V]
ITMX T240 1 DOF Z/W = 0.374 [V]
ITMX T240 3 DOF X/U = -2.979 [V]
ITMY T240 1 DOF X/U = -0.499 [V]
ITMY T240 1 DOF Y/V = 0.328 [V]
ITMY T240 2 DOF Y/V = 0.347 [V]
ITMY T240 2 DOF Z/W = -0.417 [V]
ITMY T240 3 DOF X/U = -1.206 [V]
ITMY T240 3 DOF Y/V = -0.47 [V]
ITMY T240 3 DOF Z/W = -3.195 [V]
BS T240 1 DOF X/U = -1.427 [V]
BS T240 1 DOF Z/W = 0.638 [V]
BS T240 2 DOF X/U = 0.764 [V]
BS T240 2 DOF Y/V = 0.335 [V]
BS T240 2 DOF Z/W = -1.276 [V]
BS T240 3 DOF Y/V = -1.523 [V]
HAM8 1 DOF Y/V = -0.535 [V]
HAM8 1 DOF Z/W = -0.873 [V]

All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.149 [V]
ETMX T240 1 DOF Y/V = -0.205 [V]
ETMX T240 1 DOF Z/W = -0.224 [V]
ETMX T240 3 DOF X/U = -0.192 [V]
ETMX T240 3 DOF Y/V = -0.251 [V]
ETMX T240 3 DOF Z/W = -0.228 [V]
ETMY T240 1 DOF X/U = -0.1 [V]
ETMY T240 1 DOF Y/V = 0.123 [V]
ETMY T240 1 DOF Z/W = 0.164 [V]
ETMY T240 2 DOF X/U = -0.147 [V]
ETMY T240 2 DOF Y/V = 0.161 [V]
ETMY T240 2 DOF Z/W = -0.051 [V]
ETMY T240 3 DOF X/U = 0.167 [V]
ETMY T240 3 DOF Y/V = -0.084 [V]
ETMY T240 3 DOF Z/W = 0.052 [V]
ITMX T240 1 DOF Y/V = 0.064 [V]
ITMX T240 2 DOF X/U = -0.04 [V]
ITMX T240 2 DOF Y/V = 0.183 [V]
ITMX T240 2 DOF Z/W = 0.216 [V]
ITMX T240 3 DOF Y/V = 0.1 [V]
ITMX T240 3 DOF Z/W = -0.099 [V]
ITMY T240 1 DOF Z/W = 0.095 [V]
ITMY T240 2 DOF X/U = 0.227 [V]
BS T240 1 DOF Y/V = 0.284 [V]
BS T240 3 DOF X/U = 0.106 [V]
BS T240 3 DOF Z/W = 0.3 [V]
HAM8 1 DOF X/U = -0.189 [V]
 

2026-09-11 16:06:07.290491
There are 5 STS proof masses out of range ( > 2.0 [V] )!
STS C DOF X/U = 10.0 [V]
STS C DOF Y/V = -10.0 [V]
STS C DOF Z/W = -2.641 [V]
STS EY DOF X/U = -5.513 [V]
STS EY DOF Z/W = 4.467 [V]

All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.465 [V]
STS A DOF Y/V = -0.803 [V]
STS A DOF Z/W = -0.603 [V]
STS B DOF X/U = 0.033 [V]
STS B DOF Y/V = 0.979 [V]
STS B DOF Z/W = -0.355 [V]
STS EX DOF X/U = 0.457 [V]
STS EX DOF Y/V = -0.708 [V]
STS EX DOF Z/W = -0.483 [V]
STS EY DOF Y/V = -0.036 [V]
STS FC DOF X/U = 0.165 [V]
STS FC DOF Y/V = -1.218 [V]
STS FC DOF Z/W = 0.589 [V]
 

ISI CPS

FAMIS62990

Last time this was run seems to be in May (90233). ETMY ST1 H2 seems more elevated compared to last time this was run. Everythign else looks okay to me.

HEPI Pump Trends (FAMIS #63076 )

Attached are trends for 45 days of HEPI pressure signals and they are pretty flat.  (This is for FAMIS 63076.)

(NOTE: Recently restarted Operator FAMIS checks and this one's ndscope template originally did not run due to "old" channels--this is because of the because Beckhoff switch for the HEPI pumps earlier this year--new template updated and mentioned this to Jim.)

Fri Ops Day Transition

TITLE: 09/11 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 4mph Gusts, 1mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.13 μm/s 
QUICK SUMMARY:

Focus will be for prep & venting EX for ETMx (with 2nd round of TMDS (Test Mass Discharge System [aka "Rai Gun"] or in-chamber incursion).

QOSEM Noise Hunting - Coil Driver & DAC Noise

Summary: It seems like noise from the coil driver and DACs cannot explain the excess noise seen on the BBSS QOSEMs. The old 18Bit DACs would be limiting in R,P,Y DOFs below 10Hz, The new 32Bit DACs and coil driver are subdominant to ISI noise.

This is one in a series of posts investigating the excess noise seen on the BBSS M1 QOSEMs. In short, at both LHO and LLO, the noisefloor of the QOSEMs appears to be around 8pm/rtHz at 100Hz, quickly increasing to 50pm/rtHz by 1Hz; where we expect the noisefloor to be flat at ~5pm/rtHz across this bandwidth. See more details in LHO alog 91466. 

Attached in Figure 1, is a noise budget for the BBSS M1, showing contributions from ISI motion as measured by the stage 2 GS13's (more details in LHO alog 91744), coil driver output noise, and DAC output noise (both 18 and 32 bit variants). Here we see that the DAC and Coil driver noise should not be limiting the QOSEM noisefloor, particularly above 10Hz. The 18bit DAC may be dominant below 10Hz in the R, P, Y DOFs. It's my understanding that LHO is using the 32Bit DACs, while LLO is using 18Bit DACs for the BBSS M1.

The conclusions here is more evidence that it is something in the QOSEM itself limiting the noisefloor of the BBSS M1. The leading theory is that its due to excess intensity noise from the QOSEM LED. We are currently investigating solutions, like upping the gain on the sat amps LED intensity feedback loop. More details can be found in the follow ticket: 39047

ETMX is rubbing (again)

Keita, Elenna, Louis, Sheila, Oli

It turns out that ETMX IS actually still showing signs of rubbing. We thought we had been in the clear but it looks like we had just found temporary relief from it.

Over the course of trying to lock in the afternoon, ALSX started losing lock more and more frequently in similar looking ways. We couldn't find any quick obvious causes and landed on taking ETMX M0 transfer functions again (reminder that ETMX was looking healthy 2 days ago: 91833). I took an M0 to M0 transfer function measurement with the OPTICALIGN OFFSETs ON, and we saw that we were rubbing >:(. We tried different checks like turning the alignment sliders OFF and ON and eventually we stopped seeing rubbing with the OFFSETs ON (appearently what dislodged it is that we put excitations in the M0 OPTICALIGN filter bank?? I don't remember doing this), but would still see the rubbing when we turned the alignment offsets OFF. This became consistant even while we kept messing with L1 COILOUTF OFFSETs, M0 TEST OFFSETs, and R0 TEST OFFSETs. While we were doing all these tests we were occasionally seeing jolts of movement while ramping stuff on and off, something that I had seen last time and what I imagine is whatever is touching catching an edge on something else before pushing past it.

Keita and I eventually were able to find an offset in R0 Yaw that pulled the LL OSEM away from the LL flag and allowed L1 to swing freely with OFFSETs both ON and OFF. However, when we tried turning the alignment sliders off ~30 minutes later, we found that we were rubbing again even though the R0 Y offset was still on. We also then found that we were now rubbing with the alignment sliders ON, which was strange since we had thought that we had gotten it unstuck when the alignment sliders were ON. Turning R0 Y OFFSET back on did unstick us though, so we are currently free-swinging.

I haven't been able to find definitive proof that ALSX was losing lock because of L1 LL rubbing, though. Looking back through all those short locks, we see that it looks like ALSX DOF2 P (TMSX) seems to grow before we lose lock, but it's not larger than anything that it's able to handle other times during the same locks. This observation also doesn't point to ETMX, but the ETMX channels I looked at didn't show anything that would cause ALSX to drop out.

TF Settings:
- In HEALTH_CHECK, except OPTICALIGN OFFSETs ON in some situations
- DAMP OFF

Table of TFs:
Measurements can be found in $(sustrunk)/QUAD/H1/ETMX/SAG{M0,R0}/Data/
Measurements have been svn'd as: r13143 for M0 and r13143 for R0

	M0	R0
Measurement	OPTICALIGN OFFSETs	TEST Y OFFSET	Rubbing?	Comments
2026-09-10_2145   M0   L	ON	0	YES	Rubbing seen on M0 when alignment sliders were ON
2026-09-10_2145   M0   P	ON	0	YES
2026-09-10_2145   M0   Y	ON	0	YES
Got L1 LL unstuck for when the OPTICALIGN OFFSETs were ON
2026-09-10_2245   M0   L	ON	0	NO	After messing around with different offsets we suddenly were no longer rubbing on M0 when the alignment slider offsets were ON
2026-09-10_2245   M0   P	ON	0	NO
2026-09-10_2300   R0   L	ON	0	NO	Not rubbing on R0 either!
2026-09-10_2300   R0   P	ON	0	NO
2026-09-10_2310   R0   L	OFF	0	YES	Alignment sliders OFF showed rubbing on R0
2026-09-10_2310   R0   P	OFF	0	YES
2026-09-10_2342   M0   L	OFF	-25000	NO	Found the right R0 offset that made it so we were unstuck with alignment sliders both OFF and ON
2026-09-10_2348   M0   L	ON	-25000	NO

Vent Recovery, HAM5-HAM7 Relay Tube Done, HAM7 Ongoing

(Jordan V., Travis S., Gerardo M.)

Installation of the relay tube that connects HAM5 to HAM7 is done.  For the installation we started with the flange on the HAM7 side, only hand tighten the bolts, then moved to the HAM5 side flange.  For that side the compression tool made it easy to handle the bellows, however when we released the bellows no spring back was noted from the bellows because we noticed a gap between both of the flanges involved, the gap was not noted during the removal of the relay tube, we had to compress the bellows some to be able to separate the flanges.  Once the flanges were closed and torqued the volume of the relay tube was pumpdown with a small can turbo backed with a leak detector.  The pressure internal to the relay tube dropped fast, and yesterday afternoon the pressure was low enough to allow us to leak test the joints with the new copper gaskets, and no helium signal was detected by the leak detector above the background that was <1.0X10^-10 Torr*l/sec.

Taking the relay tube volume to a lower pressure
After more relay tube pumping the pressure was low enough to incorporate the its volume to HAM7, this configuration took the pressure down at the the relay tube without affecting much the pressure inside HAM7, see attached plot.  At this time we introduced its ion pump to HAM7, while pumping with the turbo pump, this configuration remained over night.  Today we checked the pressure at the relay tube and it was low enough to change the configuration again, we isolated the relay tube from HAM7 and introduced its volume to HAM5 + main vacuum volume, this is noted on the attached plot.  This was done remove the scattering that RV1 causes to the interferometer.

HAM7 Pumpdown
Today to help the pumpdown at HAM7, and proceed to a nominal configuration, we isolated the turbo pump and allowed its main ion pump to try and maintain the vacuum pressure on the chamber, at the same time we included the volume of section FC-A by opening FC-V1 to aide with its additional 150 ion pump, FC-A section still has FC-V2 closed at BSC3.  As of this afternoon the vacuum pressure at HAM7 leveled and it is turning around.

Thursday OPS Report

TITLE: 09/11 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Commissioning
OUTGOING OPERATOR: Corey
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 26mph Gusts, 17mph 3min avg
    Primary useism: 0.14 μm/s
    Secondary useism: 0.11 μm/s 
QUICK SUMMARY:
More ETMX transfer Functions are currently being ran to determine if ETMX is rubbing.
VAC team is setting up for this potenial vent.

 

 

 

Summary of today's DRMI attempts

Sheila, Elenna, Oli

Starting with a quick summary that I will update later.

In short, the problem in DRMI appears to be some cross coupling between MICH and PRCL.

Jenne noted yesterday that the BS M2/M3 crossover seems odd, but I locked MICH dark and PRMI today and checked the BS M2/M3 crossover and it is fine, as is the MICH OLG in both states. However, once we lock DRMI, the MICH OLG and the crossover look strange. We cannot proceed through the DRMI locking process and 3f switch because we can't engage our normal DRMI filters because MICH is not stable.

Our conclusion is that this comes from PRCL because we change the PRCL gain and see a change in the MICH OLG. We also have tried adjusting the phase of the REFLAIR 45 diode and this changes the MICH olg.

I was in the process of moving the phase of REFLAIR 45 and removing the PRCL from REFLAIR 45 Q, but then we realized we had a much bigger problem with ETMX, alog incoming on that later.

Unfortunately it seems the REFLAIR phasing that Jenne and I did yesterday was incorrect because we could not lock PRMI with that phasing. I reverted that phasing, and we have tried going to more positive phase on the diode instead, which is also helping.

It would be good if we could decouple PRCL and MICH. After that, I think it would be helpful if we could increase the MICH gain and bring the UGF closer to 15 Hz. Sheila and I think we can bump SRCL up to 35 Hz.

Thurs DAY Ops Summary

TITLE: 09/10 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Commissioning
INCOMING OPERATOR: Tony
SHIFT SUMMARY:

DRMI locking work continued, but the afternoon focused on ETMx investigation/troubleshooting (look for an alog on this later).

The Relay Tube was opened up to the main volume (HAM7 & "downstream" remain isolated and pumping down).
LOG:

• All Day:  BT Enclosure patch work; just passed the +3km mark (randy)
• 1500-1540 Morning Alignment:  Started aligning of cavities noted in Elenna's alog notes);  Took ISC_LOCK to MANUAL_INTIAL_ALIGNMENT: 
  • Green Arms:  Used INIT_ALIGN & selected GREEN_ARMS_OFFLOADED
    • Y-arm had decent flashes, but X-arm was not as good--tried tweaking a little by hand but SCAN ALIGNMENT took over & finished the alignment.
• NOTE:  After Green Arms, used ALIGN_IFO to select different states for aligning other cavities
  • Xarm IR: (completed WFS CENTERING XARM)
    • When Elenna arrived, we checked this again at XARM_IR_LOCKED (I think this was at 1, so no changes made)
  • PRX: (completed WFS CENTERING PRX),
    • Elenna had me redo PRX alignment:  Since no WFS, because rfpds need to get rephased after DRMI work
    • Hand Tweaks:  Went to PRX_LOCKED & then tweaked PRM to maximize AS_A_DC
  • Mich Dark: (lockloss at MICH DARK ALIGN, so I skipped this after 2nd attempt). 
    • Hand Tweaks:  Then just tweaked BS by hand by taking to MICH DARK LOCKED and tweaking BS to optimize Dark spot for AS AIR (or minimize AS_A_DC)
  • SR Align: (This is when Elenna arrived and helped me)   edit:  (completed to PREP SRC ALIGN)
  • SRY:  Go to SRY_LOCKED
    • Hand Tweaks:  While locking, SRM tweaked-up fringes (highs high/low low) 
    • SRY locks and then continue SRM tweaks to maximize AS_A_DC
  • SR2 (completed OFFLOAD SR2 ALIGNMENT)
  • PRX Again:  Make sure PRM is tweaked up (with Elenna)
    • PRM used to maximize AS_A_DC
• 1500-1548 optics lab (kim)
• 1613-1825 spackle 2hrs (chris)
• 1600-1710 TCS Property sorting (tj,christina)
• 1749-1758 H2 room clean (kim)
• 1815-1845 checking on key for a door (tj,richard)
• 1846-1909 Connect Relay Tube to Main Volume (HAM7 will remain valved off to continue pumping down) [gerardo.jordan]
• 2101 Moving parts from Corner to H2 Bldg & MY (fil + marc joining)
• 2125 Plugging in cable at psl racks for JAC measurement; but it was already connected (sheila)

BSC9 Leak Check Done

(Jordan V., Travis S., Gerardo M.)
Transported all the equipment to X-End this morning, leak detector and helium in a small bottle.  Connected the leak detector to the main turbo pump and left the leak detector pumping for some time to warm up.  Isolated the X-End large ion pump from the main volume.  Tested the small Conflat by spraying it with helium, this CF blank is installed on the TMDS injection port of BSC9 -Y door.  The leak detector registered a background of 2.0x10^-10 Torr*l/Sec, no leak was detected by the leak detector.  The leak detector was decoupled from the main turbo pump and the isolation valve was opened for large ion pump.  At this point we collected all items, 2 ISP-1000, 1 electrical bang box, and 1 leak detector, all were transported back to the corner station.

We noted that when we isolated the main ion pump for X-End the pressure dropped at the X-End main vacuum volume, and once we opened the isolation valve the pressure at the X-End main vacuum volume went up, head scratching, perhaps the ion pump is not as effective any more.  Also, the background at the leak detector was different, with the ion pump part of the volume the background was at 2.0x10^-10 Torr*l/Sec, without the ion pump the background was very low, <1.0x10^-12 Torr*l/Sec.  No RGA data available of this station, no remote connection to it was possible, and to do that locally it takes some time to setup, and we did not want to delay the GV20 opening more.

ISI HAM2 and HAM3 Driven in X for SPI H23 Calibration Run

J. Kissel

After tuning up an excitation with color that roughly matches the shape of the quiescent HAM2 and HAM3 displacement, I drove ISI HAM2 and ISI HAM3 in X as a calibration run for H1SPIH23. I'll process and post the results and conclusions tomorrow. 

MEASUREMENT CONFIG NOTES:
Input Mode Cleaner was LOCKED, but no IFO.

The SPI 
   - QPDs were well centered, with their latest calibration installed. Their normalized spot positions remained well below 0.1 [V/V] throughout the excitation. QPDA's dark noise is still terrible; that hasn't yet been resolved. QPDB should be functioning as normal.
   - MEAS and REF IFOs had their nominal contrast of ~75% and 100% respectively, and they remained as such all throughout the excitation.
   - phase unwrapper algo was reset prior to each measurement run to be sure.

HAM ISIs were isolated the entire time, with sensor correction ON. HAM3 was using the CRS in RY.
Blend configurations are screenshotted and attached.

All Suspensions in HAM2 and HAM3 were DAMPED and aligned. PR3 had its Estimators L, P, and Y ON.

(big big 6.something EQ at 11:23 UTC in Alaska / Alutians)
Reference Time  2026-09-03 17:09:49 UTC 
HAM2 excitation 2026-09-03 18:34:14 UTC - 18:58:09 UTC
HAM3 excitation 2026-09-03 18:59:31 UTC - 19:23:26 UTC

Excitation parameters and frequency dependence attached in the screenshots.
Used the same exact excitation for both platforms.
excitation bandwidth was from 0.005 to 200 Hz, but I rolled off the excitation band at either end with a 5th order elliptic with corners at 0.01 and 50 Hz.
Frequency resolution was therefore 0.005 Hz.
Took 10 avgs.

Corner station Sensor correction mode was WINDY during the HAM2 excitation.
Interestingly? Sadly? there was an 5.3 mag Alaskan earthquake in the middle of the HAM3 excitation (started at 18:59:31 UTC). That automatically changed the corner station sensor correction configuration to CONFIG_EQ at 19:05:17 UTC, then back to CONFIG_WINDY at 19:15:18 UTC.

The typical total RMS of each ISI X motion during the the excitation was ~1e-6 [m]_RMS. 

DTT Templates and results are saved to the following DTT templates
   /ligo/svncommon/SeiSVN/seismic/Common/SPI/Data
       2026-09-03_170949UTC_H1SPIH23_DIFF_DISP_ASD.xml
       2026-09-03_183414UTC_H1SPIH23_DIFF_DISP_ASD_HAM2Drive_X.xml
       2026-09-03_185931UTC_H1SPIH23_DIFF_DISP_ASD_HAM3Drive_X.xml