[Boatanchors] 2X2 question

[J. Forster]

Mark Foltarz wrote:

> I beleive that the blue gas itself indicates mercury.

Nope. There is no mercury in this tube. It's a high vacuum, high voltage, low
current device.

> The actual contamination is most likely just air.
> The air ionizes quite easily and also ionizes the mercury vapor - just not the
> way we would like...
>
> I like the idea about the osmotic qualities of helium however.

It's diffusion, not osmosis.

> Made me stop and
> think. Maybe it is atmospheric helium getting through a bad glass to metal
> seal.

Helium goes through glass. The rate depends on the glass type. Remember the
failures of early HeNe lasers?

> Even though helium ionizes with a 'watermelon pink' color, the ionized
> mercury vapor would surely override the more subtle helium.

There is NO mercury to ionize. Also gases glow colors depends on which ionization
potential is being excited.

> You could very well goto a local university physics teaching lab and talk them
> into setting up your tube in an optical spectrometer.  You could then find out
> if the there are only a few lines, sharp and distinct, indicating mercury and
> helium. Or if there are many lines, some sharp and others blurry, this would
> indicate air.

If you want to send me the tube, I'll run it for you.-John

> I just went through a similar fit with 866s. Turns out the tube wasn't the
> culprit at all in my situation. A feedthrough insulator was getting
> intermittant when it got hot. Go figure.
>
> de KA4JVY
> Mark