NAOJ GW Elog Logbook 3.2
[Takahashi, Aritomi, Yuhang]
Since the BS picomotor did not move, we opened the BS chamber and checked the BS picomotor. The BS picomotors for pitch and yaw were connected to the motors A and B in driver 1, respectively. However, we found that the motors A and B in driver 1 were broken. We decided to use the motor C in driver 1 for both BS pitch and yaw temporarily.
We noticed that the BS picomotor did not move in yaw direction although we heard the sound of the picomotor. Takahashi-san found that it was because the BS was touching the stopper of the mirror. After Takahashi-san fixed it, the BS picomotor could move in yaw.
After we adjusted the BS picomotor, the green beam is hitting on center of the first target. Finally, we started to evacuate the PR/BS chambers.
We firstly used Rotary Vane Vacuum Pump (Alcatel 2100A) to evacuate. The speed is controlled to be less than 1mbar/s to avoid large pressure applied on in-vacuum components. Its ultimate achievable pressure is 0.03mbar.
Since the turbo pump (STP1003) requires outlet pressure smaller than 0.1torr (0.13mbar), we waited for rotary pump to evacuate PR/BS chambers until pressure reached 0.1mbar.
The small rotary pump and turbo pump were kept on with gate valve closed between turbo pump and PR/BS chambers. So we just opened the gate valve after PR/BS chambers pressure is lower than 0.1mbar.
We will keep turbo pump on until the PR/BS chambers pressure reaches 1e-6 mbar. Then we will open the gate valve between PR/BS chambers and input mirror chamber.