Re: x-ray with small Tesla coil as driver

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips" <evp-at-pacbell-dot-net> 

"I faced this same situation six years ago when I also had a punctured
large
x-ray tube.  I eventually sold it at an excellent price to a
radiologist,
but the options I came up with were:
a) Check with local glassblowers, esp. those who make neon signs.
Sometimes
they will have a vacuum pump that will evacuate down to the level
needed;
b) After a lot of searching, I finally did find someone on the web
(don't
know who now, but I found them by careful searching) who offered to do
the
evacuation and sealing at a reasonable price, although there was slight
concern about the tube's age and fragile nature.  I think it was a
glassblower who did vacuum work;
c)  The vol. 4, no. 2 issue of "The Bell Jar" featured an article on a
sorption pumped x-ray tube, with vacuum created without a vacuum pump.
Your
tube could probably be evacuated this way, but you'd still be left with
the
sealing issue.

Hope this helps....
Jack"

	The key to the problem is "the tube's age and fragile nature".  It's a
valuable artifact as it stands, so I'd rather leave it as it is than
take a chance on losing it.  I suspect it might be annealed in an oven
before work started, but I don't know what that would do to something
which is already down to air.  Pumping is no problem, just the (old and
brittle) glass work part of it.

	A note on the subject of small X-ray tubes.  I have one with a 2" bulb
which was made by a friend of mine.  When he gave it to me the pressure
was too high to be useful (just a diffuse blow glow when exposed to HV.
I cut the exhaust tube a bit and have operated it on a small diffusion
pump.  By carefully playing around with the pressure I can get it to
produce a reasonable X-ray flux operating from a 1" spark coil, but when
I hooked it to a small TC it almost melted into a puddle!

Ed

Ed