Aw shucks, it weren't much. I just happened to have half a dozen scrapped microwave ovens (BillF) and the need for some CW microwaves to make an Electron Cyclotron Resonance ion source.
I guess I should re-post that stuff (perhaps re written) up on ion source forum. I've not written much more about it because I haven't had to think about it much -- it just works. That's actually pretty uncommon for a source that makes copious monatomic ions at low pressures, but you know human nature -- if it works, you move on to the things that don't.
I think he means
this, on my old web page.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.