This walkthrough will help you to re-start the pumps in the molecular beam instrument at US 4.1 after either a planned or an unplanned power outage.
Planned power outage
Preliminary remarks
This walkthrough applies only when there is no nitrogen flow available during the power outage. The turbopumps will be pre-set to ‘Venting mode: 1 = no venting’. The setup must not be vented as the detectors should not be exposed to air.
Shutdown procedure (before the power is out)
- Close the valves between the two forepumps and the remainder of the vacuum system (see pictures below).
- Turn off the forepumps. The power buttons are located on the side of the pumps.
- Turn off the turbo pumps. For instructions, see here.
Unplanned power outage
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.
When the power is back up
When the power is back, please follow this procedure:
- Close the nitrogen valve.
- Make sure the backing pumps are on and the pump valves are open (see picture). The backing pumps should automatically turn on when the power comes back and they were not turned off.
- Wait until FSRC and MEMB pressures reach 1E-1 mbar.
- Turn on the turbo pumps.
Turning 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.
