Ryan S, Sheila, Jennie W, Elenna
Using PR2_SPOT_MOVE, I moved PR3 to increase the flashes on LSC POP LF, with 10W input we are getting flashes of up to 400 counts on POP LF (compared to 2-3 counts yesterday). To do this I had to iterate between PR2_SPOT_MOVE and using PRX to touch up the PRMI flashes (I also adjusted for MICH DARK, but the main thing that was getting misaligned was PRX).
After that the flashes were hitting the top periscope mirror on the very edge on ISCT1, I moved the mirror about an inch in the -X direction, and also moved the bottom mirror also in the -X direction. I then adjusted the alignment of the periscope mirrors to get a beam to POPAIR B, this was difficult with flashes and we may still be clipping. There are flashes on POPAIR 18, much lower than normal, but they could be used to try to lock PRMI. It would be easier to align this path with a locked PRMI.
After Sheila performed this realignment, I locked PRX and MICH to check how things looked. The PRX swept sine measurement shows that the PRX gain is about 30% too low compared to the template. I didn't make any changes.
The MICH template showed that the MICH gain is now a factor of 2 too low- remember yesterday we had to drop this gain by a factor of 6.7. I increased the MICH gain to 2400 in both bright and dark align in the ALIGN IFO guardian. I don't understand this change.
Sheila and I tried further moving the PR2 spot around. There are some alignments that give decent flashes on POP A LF and some small flashes on POPAIR B. However, at 2 W these flashes are too small to trigger a PRMI lock.
I briefly went to the table- it looks like maybe the beam is in danger of clipping in yaw on the shutter as it comes of the periscope, but I'm not sure.
We can see beam flashes on both POP A LF and on POP X WFS DC. Seg 3 of the WFS is much larger than the other three segments, but I haven't been able to improve the centering with PM1 scanning.
Jennie, Ryan, and I took the power to 10 W, where the flashes on POPAIR B around between 10 and 20. However, we couldn't figure out how to trick the trigger matrix into locking PRMI.
Attached are screenshots of the swept sine results and the alignment sliders after PRX and MICH locking.
