Sat Feb 14 10:14:53 2026 INFO: Fill completed in 14min 49secs

FW0 spontaneously restarted itself at 17:49 Friday 13th February 2026.

The DAQ was last restarted 16:05 Thursday 12th February, and FW0 had been running 1day 1hour 44minutes at the time it restarted. There have been no further restarts.

TITLE: 02/14 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Productive day with the HAM1 EOM being adjusted to recover IMC alignment, which locked easily and has a good REFL demod phase. Sounds like the EOM needs to be moved again slightly next week, but that's been prepped for this afternoon. A few AUX carts were disconnected in the LVEA as well today.
LOG:

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

Late entry-

Late Wednesday we vented the annulus system for HAM4 using nitrogen.  On Thursday, we removed and replaced the ion pump, a very uncomfortable location for this pump, it is surrounded by cable trays, see photos.

We have not been able to fasten the mounting bolts that hold the ion pump body in place, we have noticed that the pipes for the annulus system leading up to the mounting flange are not parallel to the ion pump flange they are |/ and they should be ||.  So, we have to twist the pipe to be able get it parallel to the pump.  We have a mechanical block supporting the pump as a temporary support, we'll replace it as soon as possible.

T. Sanchez, J. Oberling

This afternoon we took a look at the JAC Refl path and positioning of IOT1.  We ended up pushing IOT1 in the +X direction by ~1"; new marks were made on the floor to represent this position.

From here we used JACR-M1 and JACR-M2 to align the beam through the viewport simulator and onto the top periscope mirror of IOT1.  This only took a couple of iterations before things looked mostly OK.  The beam is currently a little low in the viewport simulator, maybe 0.5" to 1" (rough measurement by eye) and is hitting the top periscope mirror.  We finished by measuring the beam height at 2 places on the ISI table roughly 28" apart, to give us an idea of how the beam is pitched.

• Point 1: 109.0 mm
• Point 2: 108.25 mm
• Pitch: ~1.05 mrad down

This seems OK for now, but on some reflection while sitting in my office typing this alog we may want to briefly revisit this.  The beam is slightly pitched down and is high on JACR-M2 (~0.5" on a 2" diameter optic), so I think there is some room to improve this, to get the beam closer to center on JACR-M2 while still passing through the viewport simulator and onto the top periscope mirror of IOT1.  More to come.

I checked the IMC REFL demod phase. Locking the IMC was very easy- with 100 mW coming from the PSL, I selected "locked" on the guardian and it locked right away, good work from the team in alog 89106!

I injected a 400 ct line into IMC L at 50 Hz, following similar steps done by the JAC crew here.

I only saw the line in I phase, so I tried taking a no injection reference and also bumping up the injection to 800 ct to see if there is signal in Q phase. There is no visible signal in Q phase. Therefore, I declare that the IMC refl demod phase is just fine at 20.87 deg.

The attached plot shows the injection time in the red and blue live traces in I and Q, and the no injection reference time in pink and blue.

I ran another excitation at 10000 ct to generate the second plot attached.

Richard asked for a one-day trend of the dust monitor at BSC2 since he moved it from the floor up to the dome platform (alog89137); see attached. Heightened counts from today likely from cable pulling activities around/on top of HAM3 nearby.

Morning report.

Pictured the beam position on the input and the output side plate of the EOM.

We'll see if it's off or not, doesn't look bad but we'll see once I have time to look at the pictures.

We realigned the beam into IMC, mode mismatch < 0.4%.

I just assumed that the MC alignment itself was good. I found MC2 in misaligned state and changed it to aligned.

We had to work both on PIT and YAW, but mostly in PIT (i.e. the difference in horizontal beam deflection between the old batch crystal that we're using and the new batch crystal is smaller than the difference in vertical deflection). 

Good news is that the mode matching is still pretty good. Attached is the MC2 trans VS time while the PSL frequency was ramped. Assuming that the tiny thing pointed by the green arrow is actually 2nd order HOM peak, the mismatch is 0.036/9.4~0.4%. Consider this as an upper limit, because it's hard to tell if the "peak" is actually a peak, could be noise fluctuation.

Fri Feb 13 10:15:27 2026 INFO: Fill completed in 15min 23secs

Gerardo confirmed a good fill curbside.

Robert, Dave:

Thursday 12th February 2026

h1pemex was changed, the newly installed AMON subsystem which reads the current to ground signal now drives the 4th channel of the 20bit-DAC via the GDS_3/DACOUTF_3 filter module chain.

h1pemey was modified to fix a typo I had made to the DACOUTF_3 filtermodules, it was missing the underscore.

Both models were restarted at 15:55, followed by a DAQ restart at 16:01-16:06

I created MEDMs for the new DAC drive system. I'll work with Ryan S on integrating this with his "GDS DAC DRIVE" screen, currently I've added buttons to the bottom of Ryan's MEDM to open mine.

TITLE: 02/13 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 3mph Gusts, 2mph 3min avg
    Primary useism: 0.07 μm/s
    Secondary useism: 0.59 μm/s 
QUICK SUMMARY: Another cold and foggy morning at LHO. Today, the EOM with its new crystal will continue to be aligned in HAM1 while the JAC reflected path is finalized pointing to IOT1. HAM7 continues to pump down as well.

Jennie W, Jason O, Keita K, Betsy W, Camilla C

Summary: EOM alignment and position captured, moved to opics lab for crystal replacment, JAC-REFL path alignment in progress.

This morning Jason, Keita and I checked the centering of the HAM1 irises after the JM3 alignment Olli and I did on Tuesday. We didn't move the irises right after JM3 as this seemed centred. We did reposition the iris right before the HAM2 septum plate in x and y.

This, along with the alignment of the IMC Olli, Jenne and I did on Tuesday, captures where the beam was with the current EOM installed.

Keita marked the EOM base position with a dog clamp and removed it to the optics lab for crystal replacement. The shims for the EOM and the screws that hold it to the table are in a foil packet on the +Y - X HEPI pier.

Betsy, Camilla and I rechecked the REFL path and spent some time moving JACR-M2 to centre it on the incoming and outgoing beams. Then we pitched down this mirror so the outgoing beam hit the upper periscope mirror. After this Betsy had some concerns that we were too close to where the JM3 tip-tilt will sit (we are  currently using a siskiyou mount for this mirror). So we yawed the JACR-M2 mirror so the beam hits the viewport slighly more to the right (as viewed from -Y side). Looking at the placement on the viewport simulator, the beam is low and right on the viewport, whereas it comes to the table, high and right in the bellows hole. This table it almost at the top of its adjustment range, so Jason and I plan to go in this afternoon and see it we can move up the table feet so the beam can move up in the viewport a bit. Betsy and I measured the tilt of the beaM from JACR_M2 off the table. The heigh is 103 mm at the table hole 8 inches from the -X edge and 8 inches from the +Y edge. It tilts up to 113mm at the last hole in this row on the -Y side.

Betsy and I also checked the pitch of the beam entering and leaving JAC after the EOM was removed. The input beam to the JAC was 102 mm above the table, the output beam before the L1 lens was the same height, and the beam height just before JAC_M3 was also 102mm. There is not a large distance between the JAC and JAC_M3 steering mirror so it is hard to get a good measurement of any small pitch in the beam. Pictures for this alog are coming.

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

Pumpdown was restarted this morning around 9:11 am local time.  After pressure inside HAM7 reached 0.5 Torr we switched over to the turbo, we had a very smooth transition.  After the internal pressure of HAM7 reached 5.0x10^-05 Torr all O-ring isolation valves were closed (we have one at the turbo pump, another at the chamber and one more at the relay tube).
HAM7 internal pressure after 12+ hours of pumping is 5.2x10^-06 Torr.  The attached plot has a small glitch at the 10 hour mark, likely due to the DAQ restart.

Annulus ion pump update.  The ion pump controller was turned on this morning, the ion pump controller struggled for some time as it was railed, but we did noticed that the pressure reading reported by the aux-cart (aux-cart remains connected and pumping on this system) dropped very slow, but after a some minutes the ion pump controller was not railed no more.

(Jordan V., Gerardo M.)

-Late entry

On Friday we removed and replaced the ion pump for HAM3.  We replaced the copper gasket twice, the first gasket seal had a bad leak, it was hard to see the mating surfaces due to visibility issues (laser safety goggles and not enough light).
After installing a second gasket, we started pumping down the annulus system and pressure went down fast.  Last pressure reading at the aux-cart was 4.63x10^-05 Torr.
BTW, we have other 4 (four) ion pumps to replace.

On Sept 4th we had a longer commissioning period to allow us to heat up OM2.  The main goal was to use this to characterize the mode matching of the arm cavities to the OMC, but we also made some other interesting measurements.

Summary:  heating up OM2 now costs us about 1% of optical gain, while it used to cost us 2%.  Heating up OM2 also changed the SRCL offset needed to get flat squeezing significantly, and reduced the amount of squeezing that we could get (without adjusting psams).

The interferometer unlocked (86727) while Jennie Wright was running the DARM offset step script with OM2 cold, to get a measurement of HAM6 throughput and look at OMC refl before heating up OM2.  As that link says, there wasn't an obvious connection between the DARM offset script which was in it's final steps (nearly back to normal) when the lockloss happened. 

We turned on the OM2 heater while relocking after some back and forth, then had an commissioning caused lockloss while trying to recover.  By the time we were relocked, OM2 was heated up according to thermistor 2, which is the thermistor who's timescale matched the timescale of optical gain changes in the past (see screenshot of June 2023 example).  We also had a large earthquake while relocking, so we paused after power up and before going to nominal low noise, so we do not have tracking of the optical gain using pcal in the first 30 minutes of this thermalization. 

The optical gain in this thermalization seemed to be fairly similar to the previous lock where OM2 was cold in the first hour.  The change in optical gain between OM2 hot and cold was much smaller this time around, so we needed to see the full thermalization in order to see what the gain change was.  We set the OM2 heater off 4 hours and 5 minutes after the power up, the attached screenshot shows a trend of optical gain during the previous thermalization while OM2 was cold, with a vertical cursor 4 hours 5 minutes into the lock.  The horizontal cursors show where the optical gain was at 4 hours and once the thermalization was complete, the optical gain continued to increase by 0.2% after the first 4 hours. The next screenshot shows vertical cursors also at the time of power up and 4 hours later, and the horizontal cursors are the same as on the previous screenshot (OM2 cold).   It seems that the optical gain was about 1.1% lower with OM2 hot than cold, although fitting these two thermalizations to an exponential might bring them closer by as much as 0.2%. Our current ring heater settings are 0W on ITMY, 1.5 W/segment on ETMY and 0.44W/segment on ITMX and 1W/segment on ETMX.

Since this is a different result than in the past times of OM2 changes, I've gone back to look at old times when we did this change.  One possible explanation for the difference could be ring heater settings being different. 

• 12/18/2023, cooled off while unlocked, optical gain increased 1.8% ETMX +ETMY RH 1W, ITMX 0.44W
• 9/19/2023, heated while unlocked, optical gain dropped 1.9%   (this time is confusing, it seems like the thermistors which had been disconnected were plugged in and looked to be thermalizing, but the set power was unchanged).
• 7/19/2023, heated in steps, 71484 ifo unlocked and relocked several times, perhaps calibration was reset making optical gain comparison confusing. (it did seem to drop by about 2%, but this seems more like a calibration reset) ETMX + ETMY RH 1W/segment, ITMX RH 0.44W/segment
• 7/12/2023 OM2 cooled off in lock, lockloss happened in the early part of the cooling (2% optical gain increase), ETMX + ETMY RH 1W/segment, ITMX RH 0.44W/segment
• 6/27/2023 OM2 heated while in lock, optical gain dropped by 2%, ETMX + ETMY RH 1W, ITMX RH 0.44W/segment, 0 on ITMY.

Once the OM2 heater was turned back on, the optical gain increased by nearly 1%, but the IFO lost lock before that thermalization finished.  There was a 2% decrease in POP18 during the cool off and a 3 urad shift in SRM top mass. 

While OM2 was hot, we did a few tests.

• We had a large change in the SRCL offset needed to reduce the squeezing rotation: 86739  This is interesting, in the past we have tried to change SRM alignment to see an impact on this number and it was a much smaller change.
• No squeezing time for a senstitivty comparison (not much change): 86788
• quick squeezer data set (before SRCL offset updated: 86736 with SRCL offset updated: 86739 ) , to see a comparison with OM2 cold see Camilla's plot from this morning
• Jennie Wright did DARM offset steps with OM2 hot, and cold.