Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx> At 04:52 PM 2/3/2007, Tesla list wrote:
Original poster: westland <westland@xxxxxx>It's interesting how they use it as an electron gun ... they break off the top part of the ceramic, and they pull off the anode ... I guess leaving them with a cathode gun and a grid to modulate it.
As the fascinating tome on building your own lab gear ("Building Laboratory Apparatus" by Moore, et al.) says: "Don't build your own electron guns. They're a commodity item, and a lot of time and money has been spent by the mfrs figuring out how to make them."
To that, I will add some observations of how they design and build things like TWTs.. designing and *building* a high performance electron source is very much an art. Sure, any competent hardware hacker who can run a vacuum pump can go out and heat a hot filament up and spew some electrons through an anode to make a beam. Heck, Thomson did that back in the 19th century. But to get a consistent flux, with good life, etc. is definitely non trivial.
If I knew of a tube that had the right electron optics configuration, I'd do exactly the same thing. (hey, is it any different than sawing the can off a transistor to make a photo detector)
Jim Lux