The big issue with diffusion pumps is backstreaming of oil vapors from the pump to the chamber when the high vac side of the system is in molecular flow (occurring at about 1 mTorr and less). The only way to get around this is to have a trap between the diff pump and the chamber.
However, a fusor is a device that works with gas flow (D2 into the chamber and then into the pump). This flow of gas raises the pressure into the transition regime and pretty well prevents backstreaming, at least while the gas is flowing.
So, what do you need?
Chamber, diff pump and mech pump in line A vent and gas inlet at the chamber A throttle valve of some sort between the diff pump and the chamber. Pirani gauge at the chamber Ion gauge between the throttle valve and the diff pump
Steve
Created on Wednesday, March 21, 2001 11:01 AM EDT by Steve Hansen