[Hirata, Ushiba]

Abstract:

We checked the input alignment and confirmed it seemed healthy.
After that, we centered POP FORWARD QPDs and closed GV between PRM and PR3.

Detail:

First, we aligned XARM with almost the same procedure written in klog29346 (since GRX lock is somehow not so stable, PR3 is manually aligned instead of GRX ADS).
Then, we checked the beam spot in front of PR2 (fig1: IR, fig2:GR): looks good.

After that, we centered POP forward QPDs (fig3).
Then, we closed GV between PRM nd PR3 and checked POP FORWARD QPDs again (fig4).
Only QPD2 pitch value was changed from 0.
Since amount of the change is not so large and final condition should be the same as before closing the GV, we didn't move QPDs after GV close.