Science/Engineering/Technical forums

I have an old Eureka xray tube and holder, 3-200-p. Looks like for dental use. The filament is blown. Will it still work to an significant degree without it?


Eureka X-Ray tube by macona, on Flickr

Jerry
It will work as well as blown light bulb produces light!!
I have seen comments that overvolted some produce a few x-rays through field emission but nowhere near what it did when the filament was OK

Thats kind of what I was thinking. Figured I might get a touch from field emission but wasnt sure how much.

For fun I looked on ebay and found all sorts of new tube out of russia cheap. Kinda neat.

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.