Ion Pump Standard Operating Procedure

Initial Startup

1. Attach the ion pump's CF 2.75" flange to some sort of valve which is connected to the main vacuum inside.

2. If it is not attached, attach the (black and silver colored) permanent magnet around the (matte gold colored) ion pump

3. With the controller unplugged from the wall outlet, plug in the ends of the SHV cable to the ion pump and ion pump controller

4. Plug in a BNC cable from the front of the ion pump controller to an voltmeter (or digital multimeter). The voltage output, usually in the hundreds of mV but up to 2 V, monitors the current once the ion pump is on. We will later document "normal" values.

5. Plug in the ion pump controller to the wall outlet. The light above "off" should turn on and the output voltage from the front BNC should be 9V. The wall outlet draws 0.03A.

6. Hit the "enable" button so that the controller is ready to supply voltage. Note that this button cannot be turned off.

7. While the turbo is still running, hit the "on" button to supply voltage to the ion pump. The voltage from the BNC should drop to 2V and the pressure should spike to ~1E-4 Torr before quickly dropping.

8. The light above the "on" button might briefly light up and then click off. The inside of the ion pump is dirty/has water. Initial power on heats up the elements, releases the water, which forces the ion pump to draw too much current and trip. This gas release is why we keep the turbo on; there might be a brief pressure increase. After the pressure goes a little back down (doesn't need to be all the way), hit "on" again. Repeat this process until the light above "on" stays on. It might go off after a few minutes but it should eventually stay on indefinitely.

9. Once the light above "on" stays on indefinitely (give it at least an hour), if the turbo pump and the rest of the vacuum chamber can be independently vented, close the valve to the turbo pump.

10. Turn off the turbo pump.

11. Monitor the pressure. If the outgassing/leaking is too much, the ion pump will eventaully trip. If there is a leak causing the trip, it has to be fixed. If it is outgassing, then additional pumping with the turbo on (and valve open) might be needed before the ion pump can pump out alone. The target stable pressure for the ion pump is ~10^-7 Torr.

Temporary Shut Down

Follow these instructions when you want to open up the vacuum system, say to adjust the optics inside.

1. Hit the "off" button on the ion pump controller.

2. Make note of the pressure in the vacuum chamber.

Need to confirm these steps:

3. Shut the valve to the ion pump. DO NOT OPEN THE VALVE UNLESS THE SIDES HAVE ROUGHTLY EQUAL PRESSURE.

Alternatively:

3. Vent with dry nitrogen. This will allow for the ion pump to start up easier next time.

Start up after initial sucess

Assuming everything is plugged in and the turbo gets the pressure down to ~10^-7 Torr.

1. With valves to the turbo and ion pump open, press the "on" and then the "enable" button. If all goes well, the light above "enable" stays on indefinitely.

2. If the turbo pump and the rest of the vacuum chamber can be independently vented, close the valve to the turbo pump.

3. Turn off the turbo pump.

4.. Monitor the pressure. If the outgassing/leaking is too much, the ion pump will eventaully trip. If there is a leak causing the trip, it has to be fixed. If it is outgassing, then additional pumping with the turbo on (and valve open) might be needed before the ion pump can pump out alone. The target stable pressure for the ion pump is ~10^-7 Torr.

Perminant Shut Down

1. Hit the "off" button on the ion pump controller.

2. Make note of the pressure in the vacuum chamber.

3. With the valve open, vent the vacuum chamber to atmospheric pressure

4. Close the valve to prevent contamination

5. Unplug the ion pump controller from the wall outlet

6. Disconnect the ends of the SHV cable

7. Potneitally remove the perminant magnet if needed