corey.gray@LIGO.ORG - posted 05:25, Friday 14 June 2024 - last comment - 10:27, Monday 17 June 2024(78428)
SQZ OPO ISS Hit Its Limit and Took H1 Out Of Observing
Woke up to see that the SQZ_OPO_LR Guardian had the message:
"disabled pump iss after 10 locklosses. Reset SQZ-OPO_ISS_LIMITCOUNT to clear message"
Followed 73053, but did NOT need to touch up the OPO temp (it was already at its max value); then took SQZ Manager back to FRE_DEP_SQZ, and H1 went back to OBSERVING.
Received wake-up call at 440amPDT (1140utc). Took a few minutes to wake up, then log into NoMachine. Spent some time figuring out the issue, and ultimately doing an alog search to find steps to restore SQZ (found an alog by Oli which pointed to 73053). Once SQZ relocked, automatically taken back to OBSERVING at 517am(1217utc).
Sheila, Naoki, Camilla. We've adjusted this so it should automacally relock the ISS.
IFO went out of observing from the OPO without the OPO Guardian going down as the OPO stayed locked, just turned it's ISS off. We're not sure what the issue with the ISS was, SHG power was fine as the controlmon was 3.5 which is near the middle of the range. Plot attached. It didn't reset until Corey intervened.
* this isn't really a lockloss counter, more of a count of how many seconds the ISS is saturating.
Worryingly the squeezing got BETTER while the ISS was unlocked, plot attached of DARM, SQZ BLRMs and range BLMS.
In the current lock, the SQZ BLRMs are back to the good values plot, why was the ISS injecting noise last night? Has this been a common occurrence? What is a good way of monitoring this? Coherence with DARM and the ISS
Check on this is 78486. Think that the SQZ OPO temperature or angle wasn't well tuned for the green OPO power at this time, when the OPO ISS was off, the SHG launch power dropped from 28.8mW to 24.5mW, plot. it was just chance that SQZ was happier here.