TITLE: 02/20 Eve Shift: 0030-0600 UTC (1630-2200 PST), all times posted in UTC
STATE of H1: Lock Acquisition
INCOMING OPERATOR: Ryan C
SHIFT SUMMARY:

IFO is LOCKING at LOCKING_ALS (Once again, we lose lock in the last few mins of shift...)

IFO is in NLN and OBSERVING as of 03:07 UTC.

Overall very calm shift in which we seem to have improved squeeze locking, improving range to what it was before last weekend.

We had one Lockloss seemingly caused by oscillations in PRCL in the seconds before the losing lock - alog 82916. According to the first OLG PRCL measurements from alog 82920, Elenna found that the PRCL2 gain was low by about 30-40%. Following this, she made a change to up the gain from 1 to 1.4 (alog 82917). Accepted SDF attached.

While 1.4 was a bit too high and caused a PRCL ring-up and a LL at LOWNOISE_LENGTH_CONTROL (where the gain switches on), the next setting of 1.2 worked! We were able to fully automatically re-lock and get to NLN and OBSERVING. Before I went into OBSERVING, I took another OLG PRCL measurement, which is the second measurement in alog 82920.

Other than this, the infamous IY Mode 5_6 Violin has been ringing up, visible in the top right screen of the attached screenshot, which shows mode 6 as slowly increasing since Lock. New settings may be needed for this.

Just as I was about to submit, we had a LL, though there wasn't the characteristic PRCL ring-up from the last few LLs. It also doesn't look environmentally caused since wind is low, there are no EQs and microseism is high, but unchanged mostly from the beginning of the day. Currently experiencing known ALS lock issues.

LOG:

None