Dan, Evan

Some housekeeping for DRMI locking:

• We unlocked the IMC, then measured the dark offsets for POPAIR_B_RF18. This is because Kiwamu reduced the whitening gain of this channel in LHO#15272. The offset adjustments we made were −14.5 ct → −4.2 ct for I, and 48.0 ct → 13.3 ct for Q.
• For some reason the SRM M1 damping loops had been turned off. We turned them back on.
• We found that SRY had trouble locking and trouble staying locked. So we turned down the SRCL gain from −10 000 ct/ct to −1000 ct/ct. We also reduced the WFS loops gains by a factor of two.
• We removed the PDA255 and its lens on ISCT6, which were used for the ringdown measurements in LHO#15524. It was plocking ASAIR B.
• By driving SRM pitch at 141 Hz and 10000 ct, we were able to verify that the alignment signal shows up in RF36I&Q for AS A and AS B.

We wanted to reimplement the SRC WFS loops, but so far we are unable to get DRMI locks that are long enough to do anything useful with.