by Doug Coulter » Tue Nov 30, 2010 12:25 pm
If you get one, remember they are efficient enough to do some damage, like your Hg bulbs! You might get enough field emission off a pointy broken filament end to see it, but yes, nothing like a working tube makes, and probably not a well focused point source. Else, it's all too easy to just make X rays, all you need are some electrons and some high voltages, as you find when you make a fusor. You get more, hotter ones with a high Z target, but copper, stainless steel, etc will make plenty.
I've got one from a dental unit I bought for the transformer, but haven't had a reason to fire it up, I get enough X rays already.
For a long time there has been stuff up on the web about making X rays by simply overvolting some old TV tube types, and yes, it works. The old shunt regulators (6BK4) were best (And you can control the current to reasonable values with the grid) but even an old 1B3 will do if you keep the filament voltage down so as not to just short your power supply. But neither makes a nice point source useful for making pictures.
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.