[Uchiyama, Ushiba]

Abstract:

We investigated GRY beam at POS table and in front of SR2 and SR3 with targets.
We could not find any significant failure at POS table but beam spots in front of SR2 and SR3 seems high from their center.
It is necessary to discuss the procedure to recover the alignment.

Detal:

First, we checked POS table but no significant issue was found (fig1 and fig2).
Then, we checked the beam spot on SR3 by using the target, and it is obviously high (fig3).
Next, we checked the beam spot on SR2 by using the target, and it seems slightly high (fig4).

We are not so sure which mirror was moved but since beam spots on both SR2 and SR3 are shifted up, we could recover them by moving steering mirror on the suspended table inside SR2 chamber and/or steering mirrors on the POS table.