> Thanks, is there any source how to calculate the amount of the mercury > needed? I would google it, but I am finding only "how much mercury in fish" > and other encouraging stuff ;-)
It gets interesting. You'll need to multiply the volume of your envelope by the partial pressure of mercury at the cool spot temperature. Then you'll have to figure out how much mercury this is. There's a good writeup on partial pressures of mercury here: http://www.physics.rutgers.edu/~eandrei/389/NISTIR.6643.pdf Note that this is slightly affected by the other gases in your enclosure, by Dalton's law: http://library.thinkquest.org/12596/dalton.html That said, it looks like the partial pressure of mercury is around 1e-3kPa at standard temperature. A mole of mercury vapor is 22.4 liters at standard pressure (101kPa) (ideal gas law) and weighs 200g. Assuming you had a volume of 10cc, you'd have 10/(22.4*1000) * 1e-3/101 = 4e-9 moles. That, times 200g/mole yields 9e-7g of mercury, about 1 microgram. So that's the amount of mercury vapor it would take to fill your 10cc volume at a cold spot temperature of "standard temperature" at equilibrium. That, unfortunately, doesn't do you a lot of good, as you'll need excess liquid mercury to maintain equilibrium, plus the amount of mercury required to actually adsorb to your cathodes to protect them, and get wasted sticking to other surfaces. And these amounts utterly dominate the amount present as vapor. As you pointed out earlier, commercial tubes seem to use on the order of 2.5mg of mercury, which is big enough to measure out, and certainly sufficient. I've seen liquid mercury beaded up in nixie tubes, so too much (within reason) doesn't seem to be a problem. I understanding not wanting to waste it, but I'd just kick in 2.5mg. Mercury is cheap, and if you have some left over, it costs much more to dispose of it than to obtain it in the first place! While researching the above, I found this lovely page that discusses gas discharges, and touches on mercury and its effects on ionization and resonance energies. It's a good read, and includes amusing phrases like "collision of the second kind". http://mysite.du.edu/~jcalvert/phys/dischg.htm - 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/4F1B74E2-284D-48FD-85D2-1C424936167D%40mac.com. For more options, visit https://groups.google.com/groups/opt_out.
