elenna.capote@LIGO.ORG - posted 15:11, Wednesday 13 November 2024 - last comment - 16:11, Wednesday 13 November 2024(81260)
ETMX transition still a problem
Unfortunately, changing the ramp time in the IX L3 to EX L3 transition to 2 seconds (from 10 seconds), seems to overall have made things worse. The first lock attempt through this state was successful, but there were four locklosses last night in state 558, each with 1 second state duration and none tagged as IMC.
Sheila and I changed the ramp time to 20 seconds, to test if ramping slower is better. Besides that, it seems like we should measure the loops before and after the transition on the way up to check the stability of the DARM loop.
The 20 second ramp appears to have worked. Still an oscillation, but with a much lower amplitude.
We tried to make an OLG measurement before and after the transition, but the template we used before the transition caused a big wiggle in the buildups so we didn't actually get any data. We ran the template after the transition and noticed the gain was low by about 15%.
Attached screenshot shows two OLG measurements because I forgot to add the most recent measurement as a reference. Upper left red measurement was taken Jun 20, 2024. Lower right red measurement was today.