sheila.dwyer@LIGO.ORG - posted 20:23, Friday 28 August 2020 - last comment - 11:32, Sunday 30 August 2020(56632)
IFO left without squeezing for a cross correlation measurement post TMDS
Starting just before 3:15 UTC on August 29th, I am leaving the IFO alone without squeezing injected so that we can try to get a long strech of data with for a cross correlation post TMDS. I requested NO_SQUEEZING from the SQZ_MANAGER guardian, then paused the squeezing guardian to prevent ISC_LOCK from re-requesting squeezing.
From the summary pages (20200829), we got about 3 hours of cross correlation time Friday night.
The IFO relocked to low noise (without the squeezer) 2 times, which seems to have been autonomous unless someone logged in and helped it out. In the second lock we got about 8 hours of data for the cross correlation. In the third lock ETMY MODE1 violin mode rang up and eventually broke the lock. Cheryl observed that this mode rings up when the damping is reapplied after we change the coil driver state 56630. For now I've set the gain for ETMY MODE1 to 0 in the guardian, so we will need to damp it by hand.
When I logged in this morning, the IMC would not lock. The problem was that the LASER POWER guardian was stuck in GO_TO_POWER_10W. I have never seen this problem before, it was solved by re-requesting POWER_2W (which had already been set as the request).