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?

Tony, Ibrahim, Sheila

While we are observing, the OFI temperature will be stepped once an hour for the next 7 hours.  I wouldn't expect this to impact the IFO or noise much, but tagging Detcahr just in case.  

The script is running on cdsws39, I'll leave the terminal open on the 1st workspace.  I'm hoping to get 7 hours of data from this with the IFO locked, but if the IFO unlocks this script shouldn't interfere with relocking so it can just be left running. 

Here is how the PR3 and SR3 signals show up at various ports.

I drove a pitch line from PR3 M3 and SR3 M3 at 8.125 Hz with the ASC notches on. I was able to see at signal with a 10 ct drive on PR3 pitch and 60 ct drive on SR3 pitch.

Templates saved as {PR3,SR3}_M3_injection_all_ports.xml in /ligo/home/elenna.capote/POPX_test in case the data is useful to you.

PR3 appears strongly at REFL and POP in I and at AS in Q. SR3 appears strongly at AS in Q and POP in Q.

Will try to repeat for yaw.

Lockloss during commissioning (though not due to commissioning). Lockloss Tool

No immediately obvious cause other than first kicks being EX Osems ~86ms pre-lockloss. DARM IN1 also saw a kick ~-92ms (attached)

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,

FAMIS 31111

I adjusted the ISS refsignal last Tuesday to bring the diffracted power back up to around 4%, which is clearly seen in the stabilization trends in a reduction in PMC transmitted power. No other major events of note this week.

started with running scan alignment and scan SQZ ANG.  Moved filter cavity detuning to 3100 Hz

• 	UTC time	start gps time	RF6 phase (really RF3)
  SQZ (ref0)	16:45 16:50 UTC	1446828330	192.2
  mid sqz - (ref1)	16:53:30 - 16:57:30	1446828830	241
  a sqz (ref2)	17:05  -17:09 30	1446829499	237.1 (CLF +)

  Lockloss while tuning phase for the other mid sqz, we don't have a no sqz referecnce for this data set.  If someone wants to try to salvage this, a recent no sqz time is here.  

TITLE: 11/10 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 148Mpc
OUTGOING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 4mph Gusts, 2mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.34 μm/s 
QUICK SUMMARY:

IFO is in NLN and OBSERVING as of 10:07 UTC (5 hr lock)

Wind is good. Microseism is still very (very) slowly coming down.

We have planned comissioning from 8:30 and 11:30 AM PT Today.

Link to report here.

• Observing performance:
  H1 achieved an average observing duty cycle of 48.77% for the week. Operations started with several issues but showed a notable recovery toward the weekend, reaching 87.1% on Saturday and Sunday.

• Environmental disturbances:
  The main causes of lock losses were earthquake-band and wind-band motion. Three significant seismic events were recorded: a magnitude 6.0 earthquake in Russia on Tuesday, 6.6 in Japan on Sunday, and 5.7 in Mexico on Friday. Additionally, there was considerable microseismic activity throughout the week.

• Spectral features:
  Persistent violin modes were observed, particularly the fundamental around 500 Hz.

• Notable noise events:
  Tuesday exhibited multiple BNS range drops and broadband noise excess across all frequencies starting around 10 UTC. Probably related with ETMX violin mode ring-up which caused excess noise in DARM, leading to lock loss. This day also registered the highest line count of the week, reaching approximately 5000.

• Detchar tab:
  Hveto pages were not generated for the last three days of the week.
  FSCAN plots reported the lowest line count on Friday (~1900 lines) and the highest on Tuesday (~5000 lines) above treshold.

• Relevant Round Winners:

  • No winners in monday, but H1:LSC-POP_A_LF_OUT_DQ repeated 3rd place in the past 7 days.

  • Tuesday: H1:SUS-ETMX_L3_OPLEV_PIT_OUT_DQ top 1 for second time in 7 days.

Below is the summary of the DQ shift for the week from 2025-10-13 to 2025-10-19

• The average range was 150 Mpc during the first few days, and later it improved to 155 Mpc.
• Glitchgram and glitch rate were normal and comparable to the previous day, with a few exceptions.
• Some low-frequency features were visible in the strain spectrogram throughout the week.
• Earthquake band and wind band motion were the main reasons for lock loss most of the time.
• Hveto pages were not created for the last three days of the week.
• Fscan- for the whole week, the line count was below the threshold.
• The Interactive spectrum is not created throughout the week.

The full DQ shift report with day-by-day details and plots is available here.

TITLE: 11/10 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 145Mpc
INCOMING OPERATOR: Ryan C
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 5mph Gusts, 3mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.35 μm/s
SHIFT SUMMARY:
H1 Has been locked all night, for 16.5 hours now.
Everything seems to be running very smoothly. Violins looking Fantastic!
Wind forecast is perfect for observing throughout the night.
And the Secondary microseism is on the way down.

LOG:
No Log

Famis 27546 Inspect quarterly trends of HWWD bits for indication of negative function.

I believe I'm just looking for channels that have no bit switching (motion) on them, which would indicate that the HWWD is no longer working properly.

First image is how the trends display on the ndscope, it's a bit hard to see all of the channels here.
But in the second image I just scaled the channels by enough to see that there is motion on all 4 channels.
ETMX HWWD apparently has the least amount of HWWD bit switching action, but there are bits being switched.
But ETMY has been a bit busy switching bits!

The test system for 4k Ethernet was moved from EY to EX, ending the test at EY.  

The link was tested between the MSR and EX at 100G for a short itme.  The link tested at 80G, the maximum the software can test.

The link is now being tested long-term at 25G.  So far, no issues.

Earlier log entry about test at EY https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=87811

M. Todd, S. Dwyer

As derived in previous alogs, we are able to relate the HOM spacing observed in each arm to the surface defocus of the test masses -- which is a combination of self-heating and ring heater power (ignoring CO2 affects on the ITM RoC). From the fits we've made of the HOM spacing / surface defocus change as a function of ring heater power we can get a value for the ring heater to surface defocus coupling factor.

Theoretically from this we should be able to solve for the self heating contribution in the test masses as well -- allowing us to constrain things like the coupling of absorbed power to surface defocus at the ITMs if we assume to know the arm power and absorption values (from HWS).

Upper Limits

If we assume no absorption in ETMs (obviously not physical), and we assume the HWS values for the ITM absorptions are correct, then with a HOM spacing measurement from each arm we can get an upper limit of the coupling factor of self-heating to surface defocus for each ITM (they shouldn't be different but this is a good exercise).

Assuming alpha is the absorption coefficient, i subscript is for the ITM, and x/y is which arm. P_y,i_rh is the itmy ring-heater. G-factors are the product of ITM and ETM g-factors. Then from the formula in section 1.2 of the notes file : Gy = Gyc - B*L*gyic*(Pyerh+Pyirh) - L*(Ai*alpha_yi*Pyarm*gyec + beta*Ai*alpha_e*Pyarm*gyic), we can solve for Ai which is the coupling factor of self-heating to surface defocus.

Middling Values

If we assume quoted absorption in ETMs (measured by LIGO, on galaxy), and we assume the HWS values for the ITM absorptions are correct, then with a HOM spacing measurement from each arm we can get a more realistic value of the coupling factor of self-heating to surface defocus for each ITM (they shouldn't be different but this is a good exercise).

Assuming alpha is the absorption coefficient, i subscript is for the ITM, and x/y is which arm. P_y,i_rh is the itmy ring-heater. G-factors are the product of ITM and ETM g-factors. Then from the formula in the notes file : Gy = Gyc - B*L*gyic*(Pyerh+Pyirh) - L*(Ai*alpha_yi*Pyarm*gyec + beta*Ai*alpha_e*Pyarm*gyic), we can solve for Ai which is the coupling factor of self-heating to surface defocus.

Summary

Both of these values indicate there is certainly an overestimation of the self-heating impact on surface defocus.

For reference, the current TCS-SIM values for this coupling factor are Ai_y = Ai_x = -36.5 uD/W.   More examination is required into this.

Links to previous alogs:

1. Estimating HOM spacing shift from self-heating alone:  https://alog.ligo-wa.caltech.edu/aLOG/index.php?callRep=84172