Naoki, Eric, Camilla
We continued the PSAMS coarse scan in 76925. Yesterday, IFO was not thermalized, but today IFO is thermalized at least for 7 hours. It seems our nominal 140/90 (strain voltage 7.22/-0.71) would be close to optimal. The detail analysis will follow.
This time, after we moved PSAMS, we compensated the alignment change caused by the PSAMS change by looking at OSEM. This works well for ZM4, but not for ZM5 and we need to touch ZM5 in addition to the compensation. This might be related to the beam miscentering in ZM5 as reported in 75770.
no sqz (10 min)
PDT: 2024-04-04 08:06:30 PDT
UTC: 2024-04-04 15:06:30 UTC
GPS: 1396278408
asqz 200/115 (strain voltage 9.59/-0.702) (5 min)
PDT: 2024-04-04 08:41:34 PDT
UTC: 2024-04-04 15:41:34 UTC
GPS: 1396280512
sqz 200/115 (5 min)
PDT: 2024-04-04 08:49:14 PDT
UTC: 2024-04-04 15:49:14 UTC
GPS: 1396280972
asqz 200/200 (strain voltage: 9.59/2.67) (5 min)
PDT: 2024-04-04 09:28:12 PDT
UTC: 2024-04-04 16:28:12 UTC
GPS: 1396283310
sqz 200/200 (5 min)
PDT: 2024-04-04 09:36:04 PDT
UTC: 2024-04-04 16:36:04 UTC
GPS: 1396283782
asqz 100/200 (strain voltage 6.83/2.72) (5 min)
PDT: 2024-04-04 09:55:09 PDT
UTC: 2024-04-04 16:55:09 UTC
GPS: 1396284927
sqz 100/200 (5 min)
PDT: 2024-04-04 10:02:23 PDT
UTC: 2024-04-04 17:02:23 UTC
GPS: 1396285361
asqz 0/200 (strain voltage 2.2/2.72) (5 min)
PDT: 2024-04-04 10:27:25 PDT
UTC: 2024-04-04 17:27:25 UTC
GPS: 1396286863
sqz 0/200 (5 min)
PDT: 2024-04-04 10:35:27 PDT
UTC: 2024-04-04 17:35:27 UTC
GPS: 1396287345
asqz 140/90 (strain voltage 7.22/-0.71) (5 min)
PDT: 2024-04-04 11:04:22 PDT
UTC: 2024-04-04 18:04:22 UTC
GPS: 1396289080
sqz 140/90 (5 min)
PDT: 2024-04-04 11:12:41 PDT
UTC: 2024-04-04 18:12:41 UTC
GPS: 1396289579
asqz 170/90 (strain voltage 8.80/-0.70) (5 min)
PDT: 2024-04-04 11:55:59 PDT
UTC: 2024-04-04 18:55:59 UTC
GPS: 1396292177
sqz 170/90 (5 min)
PDT: 2024-04-04 12:03:26 PDT
UTC: 2024-04-04 19:03:26 UTC
GPS: 1396292624
asqz 75/90 (strain voltage 5.77/-0.71) (5 min)
PDT: 2024-04-04 12:24:44 PDT
UTC: 2024-04-04 19:24:44 UTC
GPS: 1396293902
sqz 75/90 (5 min)
PDT: 2024-04-04 12:31:39 PDT
UTC: 2024-04-04 19:31:39 UTC
GPS: 1396294317
asqz 130/125 (strain voltage 7.21/0.26) (5 min)
PDT: 2024-04-04 14:58:24 PDT
UTC: 2024-04-04 21:58:24 UTC
GPS: 1396303122
sqz 130/125 (5 min)
PDT: 2024-04-04 15:06:03 PDT
UTC: 2024-04-04 22:06:03 UTC
GPS: 1396303581
asqz 130/83 (strain voltage 7.22/-1.2) (5 min)
PDT: 2024-04-04 15:39:41 PDT
UTC: 2024-04-04 22:39:41 UTC
GPS: 1396305599
sqz 130/83 (5 min)
PDT: 2024-04-04 15:46:36 PDT
UTC: 2024-04-04 22:46:36 UTC
GPS: 1396306014
On April 9th, we took one more PSAMS data. This PSAMS setting might be better than the nominal 170/95 (strain voltage 8.8/-0.66) as reported in 77074. We may come back to this setting later.
asqz 125/136 (strain voltage 7.5/0.5) (5 min)
PDT: 2024-04-09 15:36:49 PDT
UTC: 2024-04-09 22:36:49 UTC
GPS: 1396737427
sqz 125/136 (5 min)
PDT: 2024-04-09 15:43:59 PDT
UTC: 2024-04-09 22:43:59 UTC
GPS: 1396737857
Subtracted SQZ dB's for the various PSAMS settings last week: course trial #1: 76925, and course trial #2: 76949, and the previous optimzations in LHO:76507, which used SQZ ASC to hold alignments when moving PSAMS before ZM alignment scripts 76757.
I sorted the PSAMS tests by positive and negative ZM5 strain gauge voltages.
Some takeaways: hard to interpret what's happening. Could be interesting to try ZM5 strains around 0 - 0.5 V, and scan with e.g. ~0.1 V steps. I wonder if reviving the psams scanning scripts, and doing fine optimizations, would be productive at this point. I'm not sure if there's a tension between good squeezing at 1 kHz vs. 100 Hz. But some settings that give the most kHz squeezing (negative ZM5 strain) don't necessarily show the best 100 Hz squeezing (positive ZM5 strain), and vice-versa. It may just be that the optimal point is narrow, and we're taking big steps?
Attachment 1 - positive ZM5 strain - potentially more SQZ at 100 Hz, and less sqz at 1 kHz?
Attachment 2 - negative ZM5 strain - more kHz SQZ, but kinda looks lossier below the DARM pole at e.g. 100 Hz.
Linking LHO:75749 with the in-chamber beam profiles at various PSAMS settings, as we continue working to reconcile the models and measurements.