Power failure procedure: molecular beam setup US 4.1

This walkthrough will help you to re-start the pumps in the molecular beam instrument at US4.

Normal pressures. NB: the TOF pressure will reach the 10E-8 mbar range only after some time. Directly after the pumps have reached maximum speed the pressure is likely to be about 1E-7 mbar.

When the power is out

Should a power outage occur and the setup vents, please open the nitrogen valve [pictured below]. Call/message Olga at +31 627168702.

Nitrogen valve (closed) located at the back of the setup.

When the power is back up

When the power is back, please follow this procedure:

1. Close the nitrogen valve.

2. Make sure the backing pumps are on and the pump valve is open (see picture). The backing pumps should automatically turn on when the power comes back.

3. Wait until FSRC and MEMB pressures reach 1E-1 mbar.

4. Turn on the turbo pumps.

To turn on the Pfeiffer pumps (DCU 600 and the bottom left DCU), press the rightmost button (see picture). For the Edwards pump (bottom right) open the system control menu and change TURBO: OFF to TURBO: ON. All the turbo pumps should be pre-programmed and there should be no need to change any of the settings. The set rotation speed for the pumps is 660 Hz for the big turbo (DCU 600) and 1000 Hz for the small turbos.

Turbo pumps at US 4.1

Make sure this valve is open and the pump is running.

Should the pump not turn on on its own, please turn it on.