More recently, a posting about the details of handling Kr doped tubes... https://groups.google.com/d/msg/neonixie-l/WutNWZBDMAo/WVOJ-VmwNBoJ
The tubes had 0.5 μCi (micro-Curies) of 85Kr (half-life is 10.7 years) - a tiny amount. Generally, 1milli-Curie ingested will be fatal - so that's about 2,000 5092A nixie tubes when they were "hot" off the press - today, assuming the tube was made in 1970 (the 122P224 tubes I have are dated around there), that original 0.5 μCi would have decayed down to 0.028 μCi (overwhelmingly by β (beta) decay at 687 keV <http://en.wikipedia.org/wiki/KeV>), i.e. only 5.7% of the original radioactivity remains (see http://www.radprocalculator.com/Decay.aspx or http://ordose.ornl.gov/decay.cfm) 1 μCi = 3.7 × 104 disintegrations per second. Decent UV light (shorter wavelength = higher energy) certainly helps striking, IME. In the absence of daylight, you need something to kick the ionisation off - Panaplex devices had a keep-alive cathode to help, as do a lot of cold-cathode trigger tubes... Nick -- 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/c03f6caf-cf6a-4cda-b816-842c9c8e4513%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
