[Jenne, Sheila, Tony]
The PMC swap work earlier today (alog 78813) resulted in a slight shift of the alignment of the beams coming out of the PMC.
After Ryan and Jason finished getting the ref cav aligned and locked, the IMC alignment looked poor. I was able to mostly get it back by hand-moving the sliders for the PZT at the PSL periscope. I touched MC2 a tiny bit, and then the IMC was able to lock. I lowered the IMC WFS thresholds (eg H1:IMC-IMC_TRIGGER_THRESH_ON and _OFF) so that it would take over alignment. Once the alignment was pretty nearly finished, I used the IMC_LOCK guardian to offload the IMC WFS. I saved in the safe.snap file for IMCASC the PZT offsets that had been offloaded.
In parallel, Sheila worked on the ALS system. The initial goal was to check and adjust the PSL pickoff portion of the COMM beatnote, however Sheila noted that the ALS Xarm couldn't lock, since the end station PLLs weren't getting enough light from the PSL. Sheila lowered the threshold of H1:ALS-C_FIBR_INTERNAL_DC_LOW from 0.05mW to 0.02mW, and also lowered H1:ALS-X_FIBR_LOCK_FIBER_LAUNCHLIM from 0.3 to 0.2 . After this, the ALS Xarm was able to lock, and Sheila went out to ISCT1 and got the COMM beatnote up to about -1 dBm. We then convinced ALS Yarm to lock after lowering H1:ALS-Y_FIBR_LOCK_FIBER_LAUNCHLIM from 0.3 to 0.2. Sheila also changed H1:SQZ-FIBR_TRANS_DC_LOW from 0.2 to 0.05 mW and H1:SQZ-FIBR_LOCK_FIBER_LAUNCHLIM from 0.3 to 0.15, after which she was able to get the squeezer all locked up, so it seems like the squeezer should work fine when we get to that point this evening.
Attached is the SDF screenshot that Sheila took for the squeezer thresholds. The other ALS thresholds were also accepted in their safe.snap files. All of these will need to be accepted in the Observe.snap SDFs in order for us to get to Observing.
I helped the initial alignment a bit, by moving IM4 and PR2 a bit for the Input_align, and then moving PRM for PRC_align. After that, initial alignment seemed to finish on its own.
Particularly since we have been having ALS beatnote issues lately (see alog 78806 for some notes), we will almost certainly want to go into the PSL tomorrow to tweak the alignment of the optic that directs the beam to the fiber for the fiber distribution box, so that we can undo all these threshold changes. Jason makes the good point that the longest part of doing that tweak will be garbing up for going into the PSL, so it should be quite easy.
[RyanC, Jenne]
We lost DRMI lock 3 times in a row at the same place (without losing ALS lock), so it seemed like we had some DRMI alignment issues. It turns out that we are barely on POP A QPD, which is not at all the same place that the offsets are set to. For now, it seems to work well to take PRC1 out of the loop. We'll need to take a look at it in the morning though.
Our 2W power recycling gain, before full IFO alignment is complete, is already above 60. Usually in this state it is as high as 58, so this is unusually good.
We are very near the edge of IM4 trans, so dividing by a too-small number, which then makes our PRG artificially high. That makes more sense, particularly since the arm transmissions aren't higher than usual.
After Tony and I brought alignment sliders from HAM2 WD trip back 78823, the IMC locked and we moved IM3 (alot) to center the beam back on IM4 trans. Plot attached, IM3 sliders moved 450urad in Yaw, 40urad in Pitch. Jaosn is currently in the PSL so temperature changes may mean we need to readjust again later. May need to pico once we're at full lock with good range.
Usually with the IFO down and IMC locked, we have 1.91 on the IM4 trans nsum and centered beam (0.04 P, 0 in Y), plot. After the PSL alignment change yesterday we had 1.69 on the IM4 trans nsum and the beam mis-centered, mainly in yaw (0.3 P, 1 in Y) plot. See overall change here.
