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Greetings All,

While waiting for the workday to end, I found an interesting link on that X-Ray
question from a few days ago. In the case of this document, it is discussing
E-Beam welding inside a vacuum chamber. Might I be correct in assuming that my
simple neon sign transformer is Substantially less energetic than the E-Beam
gun, with regards to X-Ray formation?

Here's the link,

On a related note, I ran the final leak test last night with the filament array
and electrical pass thru's installed, and things are looking very favorable for
first evaporation tonight :)

Amazingly the new chamber actually holds a much better vacuum over time, while
valved off. With the old chamber, after sitting over-night, the thermocouple
gauge would read 'off-scale high' by the next morning. The new chamber is
reading 0.1 torr after being valved off over night!

Take Care,
James Lerch
(My telescope construction,testing, and coating site)

"Anything that can happen, will happen" -Stephen Pollock from:
"Particle Physics for Non-Physicists: A Tour of the Microcosmos"

" Press on: nothing in the world can take the place of perseverance.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent. "
Calvin Coolidge

--- In VacuumX@..., "James Lerch" <jlerch1@t...> wrote:

Greetings All,

While waiting for the workday to end, I found an interesting link

on that X-Ray

question from a few days ago. In the case of this document, it is

discussing

E-Beam welding inside a vacuum chamber. Might I be correct in

assuming that my

simple neon sign transformer is Substantially less energetic than

the E-Beam

gun, with regards to X-Ray formation?

I have some background in the medical xray field. It is my opinion
that you are safe from this risk while using a neon sign transformer
for glow discharge cleaning operations. Reasons being:

1) 15kv of acceleration under hard vacuum (<1e-6 Torr) will produce
at most a very soft xray radiation which will be only barely able to
penetrate (or even fluoresce) very thin glass. If you are seeing
the glow discharge within the chamber volume then your pressure is
much higher than 1e-6 Torr. This pressure greatly increases the
number of collisions between electrons and gas molecules. Thus the
final electron impact energy with the anode (which produces x-rays)
is rather low.

2) The medical x-ray systems I designed years ago operated under a
hard vacuum with a heated, coated cathode filament. Tube voltages
started at 40kv (up to 140 kv) at beam currents of 40-500 mA. The
40kv x-rays were hardly able to penetrate much of anything. From
memory about 1/4 inch of paper would block most of the energy.

Since your neon transformer is much lower voltage, and the pressure
is much higher, I think you have nothing to worry about.

Incidentally our system could image (detect) a strip of black vinyl
electrical tape adhered to a block of aluminum over 1 inch thick!

-Bill