I have designed an electron gun that incorporates a faraday cage setup and I would like anyone's opinion if this setup could actually work. See attachment for image or here is a link to the image of the electron gun http://yfrog.com/j7electrongundesignbj Explanation of image There is a faraday cage which is connected to a negative high voltage source. A wire which is shielded from the electric field of the faraday cage is going into the faraday cage to supply power to the cathode (electron emitter). Since the faraday cage has the principles that when there is only an electric field on the outside there is no electric field on the inside but when there is an electric field on the inside there will be an equal an opposite charge on the inside of the faraday cage surface. So if the cathode has a voltage of -100 then the inside of the faraday cage will be +100 volts even though the outside of the faraday cage may be at negative 10 kilovolts. By the way the area around the cathode and the outside tube on the faraday cage are in a high vacuum My question would be is this setup possible, is it possible to emit electrons inside a faraday cage accelerate them to a positive voltage on the inside of the faraday cage and exit through a hole in the faraday cage and be then accelerated again by the negative voltage on the outside of the faraday cage. My idea is very similar to the setup of an van de graaff accelerator (http://www.lbl.gov/abc/wallchart/chapters/11/2.html) which has a penning ion source to generate positively or negatively charged ions and to accelerate them. I can not however find very much information on the design of penning ion sources other then extremely complicated designs. Any ideas/suggestions are highly appreciated.