ibrahim.abouelfettouh@LIGO.ORG - posted 07:32, Wednesday 04 June 2025 - last comment - 10:11, Wednesday 04 June 2025(84786)
OPS Day Shift Start
TITLE: 06/04 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: TJ
CURRENT ENVIRONMENT:
SEI_ENV state: CALM
Wind: 11mph Gusts, 6mph 3min avg
Primary useism: 0.02 μm/s
Secondary useism: 0.15 μm/s
QUICK SUMMARY:
IFO is in DOWN and PLANNED ENGINEERING
Plan today is to continue lock acquisition. Might attempt an initial alignment whilst the comissioners arrive.
HAM1 ISI WD has been tripped since yesterday morning. This seems to be related to lock stability issues in the last DAY and EVE.
Sheila, Ibrahim, Julia
We lost lock after 6 minutes at LOWNOISE_ASC, this wasn't clearly a CSOFT/DSOFT ringup and appears ~equally in PIT and YAW. Adjusting DSOFT gains didn't help. We are suspicious of a 1Hz instability in DC1 centering loop, plot attached.
We initially thought the 1Hz was due to HAM1 bring tripped but it didn't completely go away in the DC1 spectrum after HAM1 untripped. See attached spectra: references are with HAM1 tripped, live traces are HAM1 damped, red trace is DC1 with large 1Hz artifact.