Reports until 04:34, Thursday 06 February 2025
H1 SQZ
oli.patane@LIGO.ORG - posted 04:34, Thursday 06 February 2025 (82662)
OWL Intervention

H1 Manager contacted me because we couldn't get into squeezing. the filter cavity was having trouble locking even green. It was locking on the wrong modes(02 and 01), with FC_TRANS_C_LF_OUTPUT reading below 100. Referencing 72084, I paused the FC guardian, closed the servo for SQZ green, and checked the FC2 driftmon. FC2 had drifted A LOT in the past hours (ndscope). I tried moving the sliders until we were back in the location where we were 4 hours ago when our squeezing was good, but this wasn't enough to let us get back to a 00 mode, and moving the sliders around more in other directions didn't get me closer either. I then checked the SQZ troubleshooting wiki and plotted the M3 witness channels along with the driftmon for both FC1 and FC2. I adjusted the sliders according to the witness channels for FC1 and we got back to a 00 mode! I then fiddled back and forth between using the driftmon channels and using the witness channels to maximize FC_TRANS_C_LF_OUTPUT until we looked good, then I unpaused the FC node and we were able to enter FDS and then Observing!

Images attached to this report