Tony and I have been troubleshooting the relocking issues since 08:00UTC, and have had no luck. We have been stuck not able to get past ACQUIRE_PRMI due to the ~10-30Hz wiggle that starts a few seconds into PRMI catching. So far:
08:05 Got on to Tony trying to lock the ifo but having trouble getting past PRMI
08:29 Took us to DOWN to revert to previous alignment values that Ryan C used earlier (1400036418 aka 05/18/24 03:00 UTC)
08:30 Started an Initial Alignment
08:55 Initial Alignment finished
- lscparams:
- PRMI_MICH W_ALS changed 3.2 -> 2.6 and NO_ARMS changed 2.8 -> 2.6 (didn't help)
- PRMI_PRCL W_ALS changed 6 -> 2 (didn't help)
- ISC_LOCK and ISC_DRMI reloaded, starting relocking
- Couldn't get DRMI, went straight down to MICH instead of trying PRMI first
- Couldn't get PRMI to lock for more than ~3 seconds, then we get the wiggle between 10 and 30 Hz and lose it
09:47 Earthquake mode activated due to incoming earthquake from Alaska
10:33 Ground mostly settled after earthquake
The oscillations seem to start a couple of seconds after getting PRMI, right before ISC_DRMI's PRMI_LOCKED gets into .run. We wanted to see if it was related to the ramp times and/or value changes happening at the same time, so we have increased the gain ramp times for lines 518 (LSC_MICH1) and 519 (LSC_PRCL1) in ISC_DRMI from 2 to 4 seconds for each, and if that doesn't work I'll be adding in timers between these lines and around the other value changes and gain ramps between those lines and the end of PRMI_LOCKED .main in ISC_DRMI.
11:18 Lines 518 and 519 in ISC_DRMI gain ramp time was increased from 2 to 4 seconds, reloaded, relocking
- didn't work, still lost lock at same place
I added 5 second sleep timers after each line where a filter value or ramp time was changed between ACQUIRE_PRMI LSC_MICH1 gain ramp time (line 518) to the end of .main in PRMI_LOCKED, and the oscillations started 3 seconds after LSC_MICH1 (this is still with ramp time set to 4s instead of 2s).
Then I changed LSC_MICH1 ramp time back to 2
- Not sure what happened this time - didn't seem to oscillate, just a short lock
Putting the detector in DOWN for the next hour until I can wake people up
Ryan C has come in for his shift this morning, so right before he came in I reverted all changes made to lscparams and the ISC_DRMI script during our troubleshooting this past night and reloaded both ISC_DRMI and ISC_LOCK. This means that the PRMI_MICH and PRMI_PRCL gains in lscparams are back to where they were at the beginning of my shift (and I believe should also match what they were at the beginning of Tony's shift, since he said he also reverted everything back to how it was originally?).