Uh, screen name: Klystron : means a drift tube that bunches electrons as they travel, not unlike a gun barrel. Used to be a RADAR tech. While joining the Physics Forum (PF), "magnetron" was already taken, so I chose a different amplitron tube: a klystron. Haven't been able to insert avatar yet but it'll probably be a USAF TAC (tactical air command) patch pic. Thanks.