[Yokozawa, Enomoto]

We observed the infrared flash of X arm cavity!!!

= What we did =
-- restore the alignmnet of IMMTs and PR2.
-- swpet the angle of PR3 (for PIT, 0.3Hz +/- 500 urad. for YAW, ramping throughout the oplev range), while monitoring the baffle PD signal.
-- found some spikes in BAFFLEPD_A/D_OUTPUT. The angle of PR3 when we found them was different from the angle good for green, mainly in YAW (~ -700urad).
-- in order to deliver IR and green to X end at the same time, rotated PR2 to compensate the difference described above. In this process, we moved the oplev QPD for PR2 horizontally, and rotated the whole suspension of PR2 with the traverser.
-- even though we only see the signals from baffle PDs A and D, roughly tried to center the IR beam on ETMX
-- confirmed I/ETMX are aligned and form a cavity for green.
-- went to X end to hopefully find the flash by an IR card.
-- just after EXT chamber, very very very faint flash was, I think, observed with an IR card, but we were not sure at that time.
-- checked the signal of PD on TMSX table for IR transmission, and it was there! Found RESONANT peaks!!! (How did TMS guys aligne IR optics without IR beam? What a miracle!)
-- covered the optics for IR with aluminum foil to reduce ambient light (see the photo).