TITLE: 09/03 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 152Mpc
INCOMING OPERATOR: Tony
SHIFT SUMMARY: Very quiet shift with H1 locked and observing throughout; lock stretch is currently up to 8 hours. A M5.3 EQ out of Japan rolled through about an hour ago but didn't even put us into EQ mode.

Bi-weekly Histograms of Locking statew times.

Histogram of time spent at NLN or higher:
Length of data 22
max Duration 2613 Min
Average 770.5 Min
% below 5 minutes : 0.0
Between 2025-08-20 00:27:34  and  2025-09-03 00:27:34
 

PowerUp Histogram
Length of data 30
max Duration 39 Min
Average 24.966666666666665 Min
% above 30 minutes 73.33333333333333
Between 2025-08-20 00:45:04  and  2025-09-03 00:45:04
 

DRMI-Histogram
Length of data 51
max Duration 49 Min
Average 11.647058823529411 Min
% above 5 minutes 54.90196078431373
Between 2025-08-20 00:46:03  and  2025-09-03 00:46:03
 

ALS Histogram
Length of data 53
max Duration 30 Min
Average 5.471698113207547 Min
% above 5 minutes 32.075471698113205
Between 2025-08-20 00:46:40  and  2025-09-03 00:46:40

TITLE: 09/02 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Observing at 149Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: A fair amount of work done even though it was looking to be a slower maintenance day. We managed to stay locked for a few hours into it, while staying in light maintenance mode. We relocked automatically with an initial alignment, then lost lock 39 seconds later from an ETMX glitch. On the way up the second time, Elenna opportunistically tuned up PRMI ASC since it has shown some signs of non-convergence (alog86694). We have now been locked for 2.5 hours while a small dropout when the SQZr unlocked.
LOG:

• 1627 Lock loss from maintenance activities
• 1734 ISI BS WD tripped
• 1846 GRB short - Fermi E596650
• 1941 Back to NLN
• 1942 Lock loss
• 2109 Observing
• 2204-2207 Briefly out of observing while the squeezer unlocked and relocked

TITLE: 09/02 Eve Shift: 2330-0500 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Observing at 150Mpc
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
    SEI_ENV state: CALM
    Wind: 10mph Gusts, 5mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.11 μm/s
QUICK SUMMARY: H1 has been locked for 2 hours.

• Dust monitors for the Optics Lab and Diode Room both report counts have not changed
• Wind and ground motion low
• All other systems nominal

FAMIS 31101

The fire alarm yesterday briefly shut off air handlers, so we see some temperature changes in several places that appear to have all settled back to nominal. Also, Jason's PMC, RefCav, and ISS adjustments this morning are seen clearly. No other major events of note in the past week.

FAMIS 26684

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

TonyS and RickS

Today, we measured the transmissivity of one of the SPI HR mirrors and the AR surface reflectivity of one of the SPI beamsplitters, as requested by Jeff Kissel.  The reflectivities of the beamsplitters were measured earlier, see this aLog entry.

HR mirror reflectivity:  We used a set of Gentec power meters procured for the Pcal effort.  An SPI HR mirror (see attached photo for details).  Aligned at 45 deg. AOI with s-polarized light, the power transmissivity (P_trans/P_inc) was measured to be 23 e-6 W/ 567 e-3 W or 4.1e-5 (0.004%). 

BS AR surface reflectivity: The reflectivity of the AR surface of a 50/50 beamsplitter was measured in two ways, both after mounting the BS with the AR surface closest to the input beam.

1. Using the PS5 Pcal power sensor and blocking the beam reflected from the 50 % reflectivity surface near the beamsplitter, the output voltage (after zeroing the no-laser-light level) was - 0.387 mV.  With both the main reflected beam (~ 50 % of the incident light) and the beam reflected from the AR surface, the voltage was - 1.3699 V.  Doubling the voltage for what would have been expected with the full incident power, the estimated AR reflectivity is  0.387 e-3 / (2 x 1.3699) = 1.4 e-4 or  0.014 %.

2. Using power meters to measure the power in the beam reflected from the AR surface and the power incident on the BS, we measure 52.6 e-6 W / 564 mW = 9 e-5 or about 0.01 %.

Fil, Camilla, Sheila. WP#12784

In 86323 we noticed a high pitched noise in SQZT7. Today we found the SQZT7 picos were enabled. When Sheila disabled them, the noise disappeared. It did not come back when they were re-enabled. 

All picos should be off in Obserivng so I monitored the sdf. However, even when enabled, the picos should not make this noise. Fil suggests we watch this pico controller closely as when used it it might intermittently get stuck trying to drive and start to make this noise again. 

Tagging DetChar:  this pico has been on in Observing from 24th June until 2nd September.

We made it up to NLN at 1941UTC but this only lasted 39 seconds before an ETMX glitch took us out. On the way back up we noticed that it would need to go through PRMI, so Elenna took the time to fix it since we ran into some issues with it last week (alog86618). We wrapped up a few SDFs that were left over from maintenance day activities, and then to observing at 2109 UTC.

After problems with PRC1 ASC, reported here, I checked the PRC1 P error signal and saw that the REFL signal seems to have a small offset. However, it appears that the POP X I signal has no offset, so I updated the error signal and tested the sign. The ISC DRMI code is updated with this new matrix.

Sheila, Matt, Camilla

As the interferometer stayed locked during the early part of maintence day, we did some injections into the filter cavity length to try to measure the noise caused by backscatter.  (Previous measurements 78579 and 78262, recent range drops that we think are filter cavity related: 86596)

The attached screenshot from Camilla shows the excitations and their appearance in DARM. (Compare to Naoki's measurement here, and to the time with no injection but elevated noise here).   I made a simple script to make the projection based on this injection, which is available here.  It does show about a factor of 3 a higher level of noise in DARM than Naoki's projection 78579, this is large enough that we should add it to our noise budget but far too small to explain our low range times last week.

• Dtt file is userapps/sqz/h1/Templates/dtt/filter_cavity/backscatter_20250825.xml
• reference 14-16 no excitation
• 17-18 amplitude 1000
• ref 20-22 amplitude 3000
• ref 23-25 amplitude 10000 start to see
• ref 26-28 amplitude 20000 pretty linear, maybe I unlocked FC

M. Todd

I did a sweep of the LVEA, everything looked fine.

I unplugged an extension cord from outside the PSL racks, and noted that a forklift by the 3IFO racks was left plugged it. I left it plugged in as it was.

Robert was still in there while I was doing my sweep, and he was notified that he was the last one.

TITLE: 09/02 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Preventive Maintenance
OUTGOING OPERATOR: Tony
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 5mph Gusts, 2mph 3min avg
    Primary useism: 0.30 μm/s
    Secondary useism: 0.13 μm/s
QUICK SUMMARY: A bit delayed of a entry, but we are in maintenance mode. We stayed locked until 1627 UTC (927PT) before we were knocked out by some maintenance activities.

The FSS TPD has been slowly trending down again, so I did a quick remote adjustment of beam alignment into both the PMC and FSS RefCav today.

Starting with the PMC, I turned the ISS OFF, then adjusted the beam alignment from the Control Room using our picomotor mirrors.  Unfortunately, I did not get any improvement in either PMC Trans or PMC Refl.  PMC Refl has been very slowly increasing over the last couple of months, it may be time to take a look at adjusting the amplifier pump currents; we'll monitor this over the next week or two and move forward from there as necessary.  To end the PMC adjustments, I turned the ISS back ON.  It was diffracting ~4.2% (jumping between 4% and 4.5%), so I decreased the ISS RefSignal -1.99 V (from -1.98 V) to lower this a small bit.  The ISS diffracted power is now hanging around 3.8% (jumping between 3.6% and 4%); at this new diffracted power, PMC Trans is ~105.7 W.

Moving on to the FSS RefCav, with the IMC unlocked the TPD began at ~0.78 V.  I was able to get the TPD up to ~0.809 V, an OK improvement but not back where it was at the end of the last on-table alignment.  With the IMC locked the TPD is ~0.813 V.

Tue Sep 02 10:08:32 2025 INFO: Fill completed in 8min 29secs

Gerardo confirmed a good fill curbside.

No new issues found.

Rinse and repeat.

During the commissioning window this morning, I worked on the St0 to St1 feedforward for the HAM1 ISI. This time I borrowed some code from Huyen to try the RIFF frequency domain fitting package from Nikhil. This required using matlab 2023b which seems to have a lot of computationally heavy stuff like code suggestions added so it was kind of clunky to use and I'm not sure what all of the different fitting options do, so each dof took multiple rounds of fitting to get working. I also had to add an ac-coupling high pass after the fact to the filters because they all went to 1 at 0hz. Still the results I got for HAM1 seem to work pretty well. Attached spectra are the on-off data I collected for the X,Y and Z dofs. Refs are the ff off, live traces ff on spectra. Top of each image are the asds for the ff on & off, bottom is the magnitude of the st0 l4c to st1 gs13 tf. The improvement is broad ~10x less motion from 5 hz up to ~50hz. I'm looking at the rotational dofs still, but there is less coherence there, so not as much to win.

Elenna has said this seemed to have improved chard asc, maybe she has some plots to add.