Procedure for using the Pfeiffer HiCube 80 Eco turbo pumping station to pump the magnetometer to vacuum.
It is necessary to do so if there are issues with drift associated with the SQuIDs not staying at low temperature and should be done anytime the magnetometer has been at room temperature for an extended period of time. This procedure needs to be done while the magnetometer is at room temperature. The magnetometer can be pumped on at room temperature and pumping can continue while the magnetometer is cooling back to operating temperature.
The procedure is as follows:
- Take cover off magnetometer hi-vac valve (leave valve closed!).
- Attach T junction with thermocouple to magnetometer hi-vac valve.
- Attach bellows (looks like flex line) between T junction and the turbo pump.
- Turn turbo pump station on with the green switch, press push button to start pumping
- Scroll to #309 Actual Speed menu item and wait until the read out is 1500 Hz
- Leave at 1500 Hz for ~1 minute and then crack open hi-vac valve 1/4 turn. If Actual Speed drops, close valve immediately. If Actual Speed doesn’t decrease turn open another 1/2 turn, if doesn’t drop open until resistance is felt and then rotate back an 1/8 turn.
- Watch for ~5 minutes while pumping to make sure it maintains 1500 Hz.
- Now toggle to pressure (#340). Want to get the pressure down to E-3 mbar. When pressure is down to that range, turn the Cryomech compressor on to begin cooling. After cooling the pressure should be down to E-4 mbar.
- When done pumping (i.e. happy with the pressure), close the valve!
- After valve is closed, turn off the pump using the push button (leave the green power button on). What until the Actual Speed on the pump is below 100 Hz before disconnecting the pump from the flex line.
- When putting the turbo pump back in storage, be cognizant that it is quite important that it is kept dust free as dust can damage its operation. The pump is quite expensive ~$8k so care should be taken with it.