[Kimura, Hirata, mTakahashi, Yasui, Ushiba]

Abstract:
We checked beam spot on PR2.
Both IR and GR beam sopt seem fine.

Detail:
We set target plate in front of PR2 and check beam spot of IR and GR beams.
Figure 1 shows the beam spot of GR, which is taken from PR2 side.
Figure 2 shows the beam spot of IR, which is taken from  PRM side.
GR beam seems almost center while IR seems slightly off to +Y side.

However, this beam spot differences does not mean IR and GR beams are not overlap because GR beam path used for the measurement was from PR2 to PR3 while IR beam path was from PRM to PR2.
Since the distance between PR2 HR surface and the target plate is 165.5 mm, and injection beam axis​ to PR2 is 0.686 degrees according to the wiki (https://gwwiki.icrr.u-tokyo.ac.jp/JGWwiki/KAGRA/Subgroups/IOO/OptParam), IR beam spot in this measurement should be off by several mm to + Y side with respect to GR beam position.​
So, current beam position seems fine.

After the confirmation of beam spot, we closed the side flange of PR2 chamber for vacuum evacuation.​​