Frank wrote:
Generally speaking, X ray production is considered to possibly occur above 15KV.
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Perhaps one of the most famous X ray tubes was the Lenard's tube. Again, there was no collision of electrons against a target to produce X rays.
What's the physics mechanism for X-ray production? electrons hitting the envelope (or air) and slowing down to emit X-rays? Or is there something else going on?
If you still had a radium hand watch, you would be more at risk.The first color televisions used around 25-35KV and X rays were observed in the flyback/ HV rectifier section of the set. Hence the warning on some of the later tube sets in the flyback section. The actual CRT posed no danger and I am unaware of the face ever being leaded glass. Yes it was thick but this was to protect from implosion and glass dangers.Frank
Hmm.. electrons moving at 30 keV speeds, hitting 2nd anode on front of screen. Sure they give up some of the energy exciting the phosphors, but I suspect that there's going to be some bremsstrahlung going on. Lead in the faceplate (and it *is* there, viz issues of hazmat disposal of CRTs) seems a good idea. Lead in glass also makes it clearer and less brittle (good in a huge flat plate with 15 psi on it). Might also help with other mechanical properties.
Agree, though, that the HV rectifier was the notorious source. More current, etc.. More modern tubes (even of the same number) had leaded glass envelopes to reduce the xray hazard. "the BellJar" had an article about this, as did the "Amateur Scientist".
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