Nixie tubes have an internal pressure of about 1/100 atmospheric (basically a vacuum), so I would be more concerned about atmospheric gases, such as oxygen, leaking-in rather than the neon leaking out. I suppose you could buy some spares and store them in a container pressurized with Neon; I wouldn't be surprised if they would last thousands of years under those conditions.. Many of my nixies are 50 years old, and all of them work fine, so I wouldn't worry about gas-retention for tubes made in the 1980's.
If you are concerned about the radioactive decay of the Krypton-85 (half-life of 10 years), just run the tubes at a higher voltage, with an appropriately upsized series resistor. My anode supplies (+225 to +350VDC) are significantly higher than the ionization voltage (about 170V). Yes, it does waste some energy (about 2.5 watts on my clocks). I'm hoping to fix that on my wristwatch, which reduces the anode supply after ionization to improve battery-life. -- 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/4d3e1d53-2af3-4640-9505-3f057496ed1a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
