DISCLAIMER:
1) I am NOT claiming that I have built a real proton pack. After all, I posted a topic on this very board that explains why a backpack-sized cyclotron is impossible, so, claiming of being able to build a real proton pack would be just stupid.
2) I am NOT claiming that the device I built influences ghosts in any way. All the experiments I did with it concern the effects of ion streams on normal objects. To drive the point home, this is also why I'm posting this here and not in the Paranormal forum: because what I did has very much to do with practicing electronics as a hobby, and NOTHING to do with the paranormal.

Now that everything is clear: even though it's impossible to build a backpack-sized cyclotron, there is a real device that comes very close to the operating principle of a proton pack: the ion ray gun. It's basically a portable pulsed high voltage power supply where the signals from two 555 timers are amplified through a transistor, two step-up transformers and a Cockcroft-Walton multiplier. This creates enough voltage to ionize the air near the discharge terminal; the positive ions so obtained are repelled by the terminal because it has a positive charge too.

I built an ion ray gun from the plans on Robert Iannini's book Electronic Gadgets for the Evil Genius and made a video where I show some of the interesting effects that can be obtained with it:
http://www.youtube.com/watch?v=LabLee1My-A
The video also shows what is my absolutely favorite part from any episode of The Real Ghostbusters, because it's the one that comes the closest to describing an ion ray gun. And after that clip, I repeat the experiment it showed! (of course, without any ghost :-D )

A guy could do some real “Van-Dammage” with that thing…

Nix;171161
A guy could do some real “Van-Dammage” with that thing…

Um… why did you make a Van Damme pun in a topic about an ion ray gun?

Devil Master;171182
Um… why did you make a Van Damme pun in a topic about an ion ray gun?

Oh, that's just what I always say when I see a potentially-very-dangerous new gizmo and am highly impressed with it…I immediately start speculating on what I could do with it. The pun comes from National Lampoon's Senior Trip.