TITLE: 12/28 Eve Shift: 00:00-08:00 UTC (16:00-00:00 PST), all times posted in UTC
STATE of H1: Observing at 156Mpc
INCOMING OPERATOR: Ryan S
SHIFT SUMMARY: Currently Observing and have been Locked for 4 hours. Relocking took more than half of my shift today just because the violins were so high and then due to needing to step through each ISC_LOCK state one at a time, and the BS camera issue (75060). Once we were in Observing everything has been calm. Secondary microseism is going down a bit, and wind was below 15mph throughout my entire shift.
While damping the violins at 2W, the ITMY Mode 5/6 setting of FM6 and FM10 gain = -0.1 did not work, but I was able to find a new setting that did work - FM6 and FM10 with gain = +0.1. This new setting was updated in the Violin Damping google sheet in the RF Damping (2W) column.
I also spoke with RRT Shifters Maurice van Putten and Maryam Aghaei-Abchouyeh about the violins and their relationship to ground motion and ability to lock at higher powers. This is what was said in the RRT MM that sums up the discussion:
"Discussion with Oli Patane (LHO Control Room) re H1 prevented from locking by anomalous microseismic activity and (width and strength) of violin modes. Detailed (tuning of) damping of violin modes does not seem to ameliorate this issue. Conceivably, the violin modes themselves do not directly prevent locking, rather, they are (by their high Q) diagnostics of the HF tail of seismic activity.
The violin modes are challenging also since their damping time is long - it can take a long time and depends on whether we are trying to actively damp them or not.
This appears to be a typical issue during Winter.
Locking appears to be lost in ramp up to observing mode, before the 60W laster power setting is reached.
To better understand this challenge, it may be of interest to determine (if there is) a critical power level beyond which locking fails; and if there is a correlation between the microseismic activity seen by the seismic detectors and the (width and strength) of the violin modes."
LOG:
00:00 Detector in CHECK_VIOLINS_BEFORE_POWERUP
02:41 Violins were low enough that I felt okay taking us to POWER_10W
- Stepped through states one-by-one, allowing some time afterwards for things to settle
04:09 Back to NOMINAL_LOW_NOISE
04:12 Cannot get into Observing due to CAMERA_SERVO user message: ASC-CAM_{YAW1,PIT1}_INMON is stuck! Do not advance!
- Tried taking CAMERA_SERVOS to DOWN and then back to TURN_CAMERA_SERVO_ON, but it did not work
- Contacted Dave, and Naoki turned up in teamspeak to help as well.
- BS camera needed to be power cycled
04:49 Observing