david.barker@LIGO.ORG - posted 10:21, Sunday 22 February 2026 (89224)
Sun CP1 Fill
Sun Feb 22 10:10:32 2026 INFO: Fill completed in 10min 28secs
Images attached to this report
Sun Feb 22 10:10:32 2026 INFO: Fill completed in 10min 28secs
Sat Feb 21 10:11:00 2026 INFO: Fill completed in 10min 56secs
When checking the Kobelco unit this afternoon, I found there was a standing puddle of water (~1/4in deep) on the right side (looking at control screen) of the enclosure. Moving to the back side it was found to be a leak in the aftercooler auto drain line, right at the isolation ball valve. There was a continuous spray of water coming from the threads on the upstream side of the ball valve.
The dewpoint at the drying towers was still -81C, same value as this morning, so it did not cause any issues downstream of the compressed air line. The drained water was simply collecting in the bottom of the enclosure instead of flowing out of the drain line.
There was no in-chamber work happening at HAM1 at the time of discovery so after a phone call with Gerardo, I shut down the compressor unit and isolated the air line between the compressor and the receiving tank. I then closed the purge air inlet valve at the HAM1 chamber.
There is currently no purge air going to the LVEA.
The compressor remains off, the new leak, a coolant leak was found at a ball valve, and it needs to be fixed. We have contacted the vendor and are awaiting on a response.
HAM1 remains closed for business until further notice, or a work around can be established.
Caution, watch out for volume on your device, lots of noise present on attached video.
2/21/26
A tech from Roger's Machinery came out to the the site today to diagnose the issue. It was indeed the ball valve on the aftercooler drain line, the valve body had cracked right through the threads. He swapped the ball valve and cleaned the water from the bottom of the cabinet.
Compressor was restarted, open to the receiving tank and drying towers, but the purge air outlet valve was not opened. No other issues found, the dewpoint at the drying towers dropped quickly (currently at -56C and still dropping).
There is still no purge air going out to the LVEA/HAM1, the compressor/dry air skid will continue to run over the weekend before opening back up to the LVEA purge air line.
Closing WP 13038
Here is a trend of the dew point from 17:00 Fri 20th Feb through to 09:00 Sun 22nd Feb.
(Jordan, Brandon (Rogers Machinery tech), Richard, Betsy, Gerardo)
Checked the Kobelco unit and the system is running normal, nothing to report. Dryer tower reports a dew point reading of -76.0 °C. I opened the purge air to the LVEA, took an initial dew point measurement at the HAM1 purge port, sorry no photo of reading, but it read -41.2 °C, and after one hour and 30 minutes of purging, a second measurement was taken, dew point reading of -48.2 °C.
Purge admittance valve for HAM1 is open now.
A reminder for others HAM1 has double soft covers for both doors. We were instructed to install the second one on the +Y door.
Note and reminder for others, sometime this week Rogers Machinery technicians are to return to replace the oil pump for the compressor.
Leaving site now.
Dewpoints were checked this morning before anyone entered HAM1. See pics for dewpoints at the dryer skid and at the relief valve for HAM1.
Jennie W, Keita K, Rahul K, Ryan S,
This morning Keita turned the power up to 1 W and the purge air down in order to scan the OMC and measure the modulation index.
We had some work to do to lock the JAC, the cavity wouldn't scan properly when managed by the guardian code.
Ryan and I have looked back at it and think there may be something wrong with the feedback to the PZT. It can't be the PZT itself though, because Keita and I were able to lock on the TRANS PD signal with the dither locking done manually by tuning the PZT offset to find the resonance and then turning on the feedback.
I have enclosed a picture to aid problem solving next week.
We then had problems keeping the IMC locked so Keita had to change the threshold used to check if the cavity is locked down to 2. This was changed at line 133 in ISC_library.py at userapps/h1/isc/guardian/.
trans_pd_lock_threshold = 2
We then managed to do three scans,
one with 45 MHz off, one with both on, and one with 9 MHz off. Detailed analysis in progress.
After turning the power back down Keita and Rahul swapped the mirror we currently have in front of the TRANS PD, with the uncoated laser window that is meant to be there (JACT_BS1).
They had to top gun and swab it to remove two dust particles first.
This replacement means the power to the PD is lower and so we needed to power up to 1W to check this alignment.
I have left the mirror we took out on the table on the -Y side labelled as 'HR mirror taken out of JACT-BS1'. Need to check which exact mirror this is with Masayuki on Monday.
Keita locked the cavity manually with the REFL PD and optimised the amount of light falling onto the TRANS PD.
I powered down to 100mW and de-energised the rotation stage and closed the light pipe at the end of the day. We also had the rotation stage de-energised and locked out when we were working in chamber.
FSR = 265 MHz (see this ref and table on P.110).
FSR in s on scan = 8.39 s
For the 9 MHz on the measurement with both sb at nominal power: : 0.0103mA is the upper 9 MHz sb vs. 0.745 mA carrier (left-hand TM00 peak).
m_9 = 2*sqrt(0.0103/0.745) = 0.235
For 45 MHZ in same measurementdata : 0.0151 mA is the upper 45MHz carrier vs. 0.745 mA carrier (left-hand TM00 peak).
m_45 = 2*sqrt(0.0151/0.745) = 0.285
The 9MHz seems similar to this (alog #89001) measurement with the previous crystal (0.26) but the 45MHz is different (0.31).
Modulation index measurement for 45M and 9M, they're healthy.
1W into JAC, no WFS for IMC, ITMY single bounce. Scanned OMC with both 45MHz minimal power (~4dBm) and 9MHz full (~27dBm), then both in full power, then only 45MHz in full (see screen shot).
Jennie will post the modulation index later, but the peaks look healthy to me.
The alignment into IMC was rather off in PIT and the guardian had a hard time locking IMC (I changed the lock threshold in the guardian). We didn't move MC, didn't bother to do any thorough investigation, but either JAC or MC mirrors moved. Maybe we have to lock IMC, use WFS for MC, and steer JM3 and see if the MC mirrors will be driven far from where they are. If they are we might have to touch up in-chamber alignment again.
JAC TRANS BS was swapped with the real one (laser window with AR only on one surface).
We replaced the JAC TRANS BS (which was a temporary high reflector until today) with the real one that is just a bare glass (the reflectivity is 7% or so depending on AOI).
We locked JAC with RF, was able to see the beam coming to the TRANS PD but wasn't able to see the reflection of PD, so we raised the power to 1W.
Initially the beam was missing the PD because the new optic is thinner than the temporary one. We realigned the optic to steer the beam back to PD. Since we could not directly see the PD surface, we just steered the beam up and down, left and right until the PD output starts to drop, and put the beam roughly in the middle.
We were able to see the PD reflection using an IR card and an IR viewer. There were two reflection blobs (which was the case before, too), and I moved the JAC TRANS BD in +X direction by 1/4~3/8" to catch both.
See results here (alolg #89230).
TITLE: 02/20 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
IFO is in IDLE for PLANNED MAINTENANCE
Calm day. HAM1 work continued.
LOG:
| Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
|---|---|---|---|---|---|---|
| 22:49 | SAF | LVEA is Laser SAFE | LVEA | NO* | LVEA is Laser SAFE *Bifurcated HAM1/2* | 16:49 |
| 15:42 | FAC | Randy | LVEA | N | Looking at test stand | 16:15 |
| 15:42 | FAC | Nellie | LVEA | Y | Technical Cleaning | 18:35 |
| 16:48 | VAC | Jordan | LVEA | N | Checking on HAM7 | 16:53 |
| 17:33 | ISC | Keita | LVEA | Y | HAM1 Lightpipe | 18:33 |
| 18:35 | EPO | Maggie + 30 | Overpass | N | Touring | 19:24 |
| 19:40 | EPO | Cassidy | Overpass +30 | N | Touring | 20:31 |
| 20:31 | PEM | Robert | EX | N | Grounding measurement | 21:44 |
| 21:07 | OPS | Ryan S | Optics Lab | Y | SPI Work | 23:17 |
| 21:23 | ISC | Rahul, Keita | LVEA | Y | HAM1, rahul out at 23:15UTC | 23:24 |
| 21:47 | ISC | Jennie | LVEA | Y | HAM1 | 23:47 |
| 23:36 | PEM | Robert | EX | N | Grounding measurement | 01:36 |
Famis 39976 Inspect quarterly trends of HWWD bits for indication of negative function.
All traces have had some motion on it in the last 91 days.
Yesterday afternoon I glued prisms to the LO2 optic for HRTS - see pictures attached.
This optic (D2100495-V5-LO2-M1-0002) will be shipped to LLO.
Famis 38888 SEI seismometer mass position check - Monthly :
Checking T240
Checking STS
Finished
Averaging Mass Centering channels for 10 [sec] ...
2026-02-20 11:36:02.279522
There are 12 T240 proof masses out of range ( > 0.3 [V] )!
ETMX T240 2 DOF X/U = -1.716 [V]
ETMX T240 2 DOF Y/V = -1.819 [V]
ETMX T240 2 DOF Z/W = -0.998 [V]
ITMX T240 1 DOF X/U = -2.377 [V]
ITMX T240 1 DOF Z/W = 0.459 [V]
ITMX T240 3 DOF X/U = -2.547 [V]
ITMY T240 3 DOF X/U = -1.089 [V]
ITMY T240 3 DOF Z/W = -3.077 [V]
BS T240 2 DOF Z/W = 0.346 [V]
BS T240 3 DOF X/U = -0.518 [V]
HAM8 1 DOF Y/V = -0.428 [V]
HAM8 1 DOF Z/W = -0.728 [V]
All other proof masses are within range ( < 0.3 [V] ):
ETMX T240 1 DOF X/U = -0.006 [V]
ETMX T240 1 DOF Y/V = -0.037 [V]
ETMX T240 1 DOF Z/W = -0.03 [V]
ETMX T240 3 DOF X/U = -0.024 [V]
ETMX T240 3 DOF Y/V = -0.07 [V]
ETMX T240 3 DOF Z/W = -0.043 [V]
ETMY T240 1 DOF X/U = 0.057 [V]
ETMY T240 1 DOF Y/V = 0.198 [V]
ETMY T240 1 DOF Z/W = 0.253 [V]
ETMY T240 2 DOF X/U = -0.087 [V]
ETMY T240 2 DOF Y/V = 0.215 [V]
ETMY T240 2 DOF Z/W = 0.046 [V]
ETMY T240 3 DOF X/U = 0.268 [V]
ETMY T240 3 DOF Y/V = 0.085 [V]
ETMY T240 3 DOF Z/W = 0.136 [V]
ITMX T240 1 DOF Y/V = 0.289 [V]
ITMX T240 2 DOF X/U = 0.131 [V]
ITMX T240 2 DOF Y/V = 0.257 [V]
ITMX T240 2 DOF Z/W = 0.242 [V]
ITMX T240 3 DOF Y/V = 0.119 [V]
ITMX T240 3 DOF Z/W = 0.061 [V]
ITMY T240 1 DOF X/U = 0.062 [V]
ITMY T240 1 DOF Y/V = 0.159 [V]
ITMY T240 1 DOF Z/W = 0.027 [V]
ITMY T240 2 DOF X/U = 0.021 [V]
ITMY T240 2 DOF Y/V = 0.243 [V]
ITMY T240 2 DOF Z/W = 0.16 [V]
ITMY T240 3 DOF Y/V = 0.082 [V]
BS T240 1 DOF X/U = 0.261 [V]
BS T240 1 DOF Y/V = -0.212 [V]
BS T240 1 DOF Z/W = -0.179 [V]
BS T240 2 DOF X/U = 0.142 [V]
BS T240 2 DOF Y/V = -0.271 [V]
BS T240 3 DOF Y/V = 0.061 [V]
BS T240 3 DOF Z/W = -0.263 [V]
HAM8 1 DOF X/U = -0.3 [V]
Assessment complete.
Averaging Mass Centering channels for 10 [sec] ...
2026-02-20 11:36:14.268587
There are 2 STS proof masses out of range ( > 2.0 [V] )!
STS EY DOF X/U = -4.582 [V]
STS EY DOF Z/W = 2.384 [V]
All other proof masses are within range ( < 2.0 [V] ):
STS A DOF X/U = -0.51 [V]
STS A DOF Y/V = -0.798 [V]
STS A DOF Z/W = -0.581 [V]
STS B DOF X/U = 0.108 [V]
STS B DOF Y/V = 0.953 [V]
STS B DOF Z/W = -0.309 [V]
STS C DOF X/U = -0.871 [V]
STS C DOF Y/V = 0.868 [V]
STS C DOF Z/W = 0.593 [V]
STS EX DOF X/U = 0.507 [V]
STS EX DOF Y/V = -0.551 [V]
STS EX DOF Z/W = -0.392 [V]
STS EY DOF Y/V = 1.204 [V]
STS FC DOF X/U = 0.153 [V]
STS FC DOF Y/V = -1.174 [V]
STS FC DOF Z/W = 0.637 [V]
Assessment complete.
Results copied to clipboard
Fri Feb 20 10:13:20 2026 INFO: Fill completed in 13min 17secs
The slow controls software was updated to include the ChetaX electronics. The chassis is currently in the MSR for test purposes, but will be moved to the cheta lab next week.
Channels are located under H1:AWC-ITMX.
TITLE: 02/20 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: 14mph Gusts, 10mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.21 μm/s
QUICK SUMMARY:
IFO is IDLE for PLANNED MAINTENANCE
JAC/HAM1 work continues
At 17:26 Thursday 19feb2026 h1iopiscex had a timing glitch causing a TIM+ADC error in its state word.
At 20:00 I restarted all the models which cleared the error.
May have been due to in-rack work. Robert may have been working on ground investigations at the time, the EX lights were not turned off until 17:49 (+23 mins from glitch).
Beam dump for HAM1-HAM2 septum window AR reflection.
This was installed.
Beam dump for the -Y door viewport reflection.
Jason and Betsy installed it. There seems to be a discussion as to whether or not something else needs to be done.
EOM and JAC power budget again.
We measured the power at various places. While Jason held the power meter head still, I ran the statistics function of the power meter for a few seconds. I only list the mean and the standard deviation.
Wrong pol is king of large, ~0.2% of the main beam power coming out of EOM. That's 200mW when 100W goes through the EOM.
JAC throughput of 92% is not great, but Jason says the alignment and the matching are not really optimised.
| JAC input | 112mW+-462uW | |
| EOM input = JAC output | 103mW+-6.3mW |
JAC OUT/IN = 0.92+-0.06 |
| EOM front AR reflection | 57uW+-4.4uW |
EOM AR/IN = (5.5+0.5)*1e-4 |
| EOM output (including the wrong pol beam) | 96.9mW+-1.4mW | |
| EOM wrong pol beam | 226uW+-17uW |
EOM wrong pol/IN = (2.2+-0.2)*1e-3 |
| EOM main pol (= out total - wrong pol) | 96.7mW +-1.4mW |
EOM main pol/IN = .9978+-2e-4 |
Afternoon work, REFL path aligned, RF lock works (Jennie, Jason, Betsy, Daniel, Keita)
It seemed as if what was supposed to be TFP after HWP was not really TFP, it was temporarily set aside.
REFL path to the JAC REFL RFPD was aligned without TFP. 100mW into JAC was enough to see the REFL beam there.
DC responded as expected.
There was a confusion about which demod chassis was used for JAC, which was sorted out by Daniel who subsequently set the demod phase. I zero-ed the dark offset.
I copied the JAC lock filter from dither path to JAC-L_SERVO path, locked JAC with dither, disabled the input to the dither servo and enabled RF locking in parallel, which worked just fine. I made rough changes to the RF servo to bump up the UGF to ~400Hz without too much gain peaking, I haven't tried anything aggressive to squash the residual motion below 200Hz, you might want to tweak it further.
I didn't disable the dither itself for the JAC PZT so we can compare the spectrum of RF and dither side by side. See attached, this was measured with 100mW into JAC, note that the dither error signal is scaled. References are with the purge air on and current traces are with the purge air completely turned down.
Guardian needs to be changed to allow smooth locking with RF.
DAQ was restarted around 12:02 PM PST after restarting h1ascimc.
There were some issues with the new code, so we reverted h1ascimc back to its original code at 13:40. We will try again next week.
When h1ascimc was restarted by itself, h1iopasc0 ran long and reported a DAC error, though on the 16bit-DAC MEDM there were no associated FIFO errors reported.
When h1ascimc was started as part of a complete model restart (rtcds start --all) this DAC error does not appear.
The DAC error is clearable by DIAG-RESET'ing the IOP, but we are unsure if the DAC is a cycle behind at this point. At the moment the safest restart if DAC errors appear is a full restart of all models.
