Incoming operator: Jeff B.

Microseism has gone over the 90 percentile.

SUMMARY:

Sheila, Jenne, Keita, Kiwamu, Robert, Evan G., Heather (new fellow) and Jeff K. were all here today. They helped find and fix two problems. The first is that the dither align scripts that I ran yesterday changed the offsets for the misalignment of ITMY. This became apparent when we saw fringes on the AS AIR camera during input align. When Keita moved ITMY, the fringes changed and then disappeared. I used Conlog to see if the misalignment offsets had changed. They had during my shift yesterday. I hypothesised that perhaps the dither alignment scripts I ran might have changed them. Jenne looked at the scripts and confirmed that they would. She has modified them so that they will not do this in the future. The second problem was that after losing lock from INCREASE_POWER (when Jenne engaged a filter?) and then again while waiting for DRMI to lock on 1f, I noticed that the alignment of ITMY jumped. Keita hypothesised that this could be a result of rubbing, and Sheila looked at the spectrum of the quad suspensions when set to SAFE (free swinging). From these it was apparent that ITMY was different. This seems to have been fixed by changing the vertical offset of the ITMY suspension relative to the ISI. After this I ran another initial alignment and was able to make it to NLN, so perhaps this also fixed the lock losses from LOWNOISE_ASC.

Once at NLN Jenne helped me set up to damp the 4735 Hz ETMY violin mode. We increased the gain for the ETMY mode 10 from .02 to .1 and then to .2. The output later began to ring up and we set it back down to .1. I accepted the SDF differences for this and earlier changes and went to observing. Almost immediately PI mode 28 rang up. I was able to damp it by changing the phase and both the sign and magnitude of the gain. When this mode was damped, PI mode 27 started ringing up. For a long period I could only bring it back down to around 1. In the process of doing so I dropped out of observing to change the PLL set frequency (H1:SUS-PI_PROC_COMPUTE_MODE27_PLL_SET_FREQ) to match the frequency count (H1:SUS-PI_PROC_COMPUTE_MODE27_PLL_FREQ_COUNT_OUTPUT). It was 238.5 and I changed it to 240.2. Eventually it came down further on its own. I then accepted this change in SDF and went back to observing. Then I noticed that the ETMY mode 10 damping output was ringing up again. I dropped out of observing again to drop the gain from .1 back to the original .02. I left it out of observing and handed the IFO over to Jeff B.

LOG:

17:06 UTC Power in arms is too low to lock ALS. Starting initial alignment.
17:14 UTC Restarted video2. CDS overview frozen.
17:31 UTC Stopping at INPUT_ALIGN_OFFLOADED to investigate fringes on AS AIR camera.
19:00 UTC Jeff K., Heather and Casey to LVEA for tour.
19:37 UTC Granted Gerardo remote access to address CP3 filling.
19:46 UTC Initial alignment done
19:47 UTC Jeff K., Heather and Casey out of LVEA
20:33 UTC Lock loss from INCREASE_POWER after Jenne engaged filter. ITMY came back very misaligned.
20:56 UTC Lock loss while waiting for DRMI to lock on 1f. ITMY moved alot again.
22:17 UTC Starting initial alignment
23:15 UTC Sheila and Evan to roof
23:49 UTC Observing
00:21 UTC Observing