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.