Re: [neonixie-l] Abridged summary of neonixie-l@googlegroups.com - 10 Messages in 2 Topics

[ron]

Hello!
All the hoopla about uv from the 866 got me to set one up and measure
it. I operated the tube with a 30ma sign transformer so it was not
anywhere near its full capacity but it had a nice blue glow between the
cathode cylinder and the anode. Using an ultraviolet meter calibrated to
right at full scale when pointed at the sun, there was absolutely no
reading from the 866. (the meter has no response whatsoever to visible
light, no matter how bright) So, the glass used in making the tube is
apparently chosen to absorb all of the UV. To test this theory I cut
open the 866 (horrors!) and took a piece of the envelope glass out into
the sun with the meter. The glass had minimal effect on the UV! So much
for that theory! So the 866 glow apparently does not have much UV at 30
ma. Not much glow to look at either though. Be a lot better to repackage
the guts and fill it with argon for a display lamp I would think. I'll
do it when I get a chance and post a youtube on it.
Oh, by the way. To the horror of the mercury vapor, I took the mercury
vapor meter (yes, I have fantastic equipment!) and did some measurements
around the broken tube. Right at the tube glass the meter pegged full
scale on the least sensitive range. Moving back a foot the meter barely
moved on the most sensitive range. (factor of 1000 more sensitive)
Moving back 3 feet, there was no detectible mercury reading at all.
Mercury is a very heavy molecule. Like a rock sinks in a pond, mercury
vapor sinks in the atmosphere to form a thin layer along the floor.
Unless you have quite a draft it stays down there. I certainly do not
propose slopping mercury all over the place though!
ron (glasslinger)

[JohnK]

Well Done That Man !
When I hoped for some quantitative observations I really did not hold much
hope.

John K.

[Nick]

All good stuff, but the critical thing about UV is its wavelength - anywhere from 10nm to 400nm.

Below 300nm, dangerous to people - above that is mainly UV-A which is not too bad - its like cholesterol - there is bad (LDL or all UV *except* UV-A) and "not so bad" (HDL or UV-A) :)

I was discussing this on a valve (tube to everyone else) audio forum in the UK - I should point out its a very quirky forum full of strange people (like me), so the tone (of the discussions) is somewhat off-beat,,, random, even...

However, the thread moved into interesting territory as some of our members are professionally into serious lens design for photo-lithography etc and some really interesting contributions were forthcoming. 

If such things amuse you, you could do worse than have a look at http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=4920

Nick