[Yasui, Yokozawa, Matteo, Akutsu]

Abstract:
IR Xarm alignment has been recovered.

Detail:
Alternating the use of PR3 target and checking beam position around IFI and REFL, we recovered some very weak flashes of Xarm by adjusting the position of IMMT2 and PR2. At this stage the IR Xarm transmission could reach at maximum 0.4. Then, we closed all the vacuum chambers and put sinusoidal excitation on IMMT2 and PR2 to further improve the alignment. By selecting good values, the Xarm transmission could reach at maximum 1.4. This was enough to try to lock. The Xarm could lock, but was not very stable due to the still not perfect alignment. The alignment was later improved engaging the dithering system by Ushiba-san.