[Nakano, Kokeyama, Enomoto]

After we changed the length between PR2 and PR3 (9266 9268), we measured the Gouy phase of the PRC again, by the cavity scan with the inertia locking method (9246).

We tried the cavity scan 4 times, and 3 of them showed good results.
The average Gouy phase inferred from the separation between the fundamental mode and the first order mode was:

31.4 +/- 1.2 deg.

The plots for the three trial of the cavity scans are attached.
The plots for the three trial of the cavity scans are attached.
(1st&2nd plots --> 1st trial
 3rd&4th plots --> 2nd trial
 5th&6th plots --> 3rd trial)