--- In NEONIXIE-L@..., Morgan Gangwere <0.fractalus@...> wrote:
<snip>
I've picked up some Burroughs B5092A's (From what I can tell from
one of their catalogs, a long-life high-visibility one) for $4 a
piece and am working on schematics for a simple clock I want to
build.
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[W]hy is there a radioactivity symbol on these?/ On all my little
nixies there's a radioactive symbol next to the name -- I can
assume because they've got amounts of 85Kr in them
(according to the label on one).
Welcome to the group, Morgan! The 85Kr is present in a few nixie types to reduce what is known as the "dark effect". Several factors affect the time it takes a nixie to ionize and light up from cold, one of the more significant of which is the amount of ambient radiation (usually light). Manufacturers added a small amount of mildly radioactive Krypton gas as a source of ions to a few types, for use in situations where they might be required to light up immediately in dark locations. Most of the radiation produced by 85Kr is low-energy Beta, which can not penetrate glass. Also, the amount present is so low that you'd literally have to smash and inhale from thousands (perhaps millions?) of new tubes at once to have any significant increased risk of harm above that from everyday background radiation. Finally, the half-life of 85Kr is less than a decade, so those tubes now have less than a tenth the radioactivity that they did when they were made. So, nothing to worry about at all, really. The radioactivity labeling is only there because the U.S. government required it.
Third, not so major question, is does anyone know of a source for
sockets? I dont want to have to solder new nixies every time one
burns out
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Firstly, nixies with rigid pins should not be soldered, and you'd probably have a difficult time of it if you tried. Second, and most importantly, type B-5092-A uses one of the most common types of nixie sockets (13-pin round), which are fairly readily available from several sources usually including Jan Wuesten, Sphere Research, and Ebay. Properly driven nixie tubes (except the earliest types) can last for decades of continuous use, so you probably won't be doing much replacing anyway.
A.J.
