Hi, In the next week I am going to NPL for physics academy and I will be designing and building a prototype electron pump. I've tried to look for articles or books related to electron pumps or how to build them but I simply can't find anything at all. Does anyone have any material at all relating to electron pumps, how to build them or some of the mathematics behind them? If you do, please could you post it here? It would be greatly appreciated thank you. I apologise for the short notice, I just don't know what else I can do to prepare for it.