> Read-up on Paschen's Law, which can explain why a leaky tube is harder to > ionize after it's pressure starts to increase. > > I wonder if we should store our nixies in a hyperbaric chamber with > neon/argon.
Both effects happen: the neon and argon leak out because even though they're at lower than atmospheric pressure, they're higher than the partial pressure of neon and argon outside the tube. And, more intuitively, oxygen and nitrogen leak in. Both of these effects are detrimental to the tube's operation. Old-style frit (or "soft") seal helium-neon laser tubes have a similar problem. The helium (a very slippery gas) would slowly leak out through the seals, so although the tube would still ionize and glow, laser action wasn't supported. The cure is surprisingly simple: "soak" the tubes in a trash bag with helium in it at atmospheric pressure. With the reversed (and much larger) partial pressure difference of helium, a few years' loss could be restored in a few days. The normal setup was to leave the tube running and monitor the laser output. It would slowly rise, then begin to drop when the helium pressure began to get too great. Take the tube out of the bag then and you could get a few more years out of it. In short, you don't need a hyperbaric chamber, atmospheric pressure will probably suffice, but you'd want to have the proper ratio of gases. - John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to neonixie-l+unsubscr...@googlegroups.com. To post to this group, send an email to neonixie-l@googlegroups.com. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/31C73C8F-B8DC-41DA-8A9A-301341F36960%40mac.com. For more options, visit https://groups.google.com/d/optout.
