[Uchiyama, Izumi, Enomoto]

As the pressure of EX reached ~ 10^-3 Pa, Uchiyama-san opened the GV at X end.
Before and after the open, alignment of the reflection from X end did not changed so much; within 10 urad.
After the open of the GV, the light power coming back from EX got doubled, to reach ~1700 cnts in REFLAIR_B_LF.
Then we checked the visibility of the Michelson, and found that it reaches as high as ~ 99%. (min: 80 cnts (BG=15 cnts), max: ~5000cnts)