Here is my thought-contruction; I take a metal vacuum part with a little volume to it (say, a tee) and I plug one opening with a high temp plastic with a fine hole running through it for about 1". I then fit a fine metal tube, into the hole facing the volume, in one end of that plastic part, but only half-way through it. I then attach electrical connections to that fine metal tube and feed them out, say through a feedthrough made through a blanking piece in one of the other ports of the tee.
Now I hook this tee up to my vac system with the chamber on the side of the plastic only, and the gas supply facing the side with the metal tube sticking in/out a little. I then apply an ionising +ve voltage to the metal tube, with respect to the tee.
What I am trying to do here is to control the flow of gas through the tube by ionising and electrotatically repelling ions away from the tube. Some ions will enter the tube, become neutralised (no e-field within it) pass out of the other end of the tube and on to the vac system. Turn up the voltage, less flow, turn down the voltage, more flow.
What could possibly go wrong!?!?