14 Mar
2013
14 Mar
'13
11:18 a.m.
I have wondered what the rate of gas infusion through
glass is at
STP, i.e. how long before the vacuum is reduced enough to affect tube
parameters. 200 years? 1000 years? 10,000 years?
Depends on the gas, among other things. Hydrogen, for exmaple,
diffuses annoyingly fast through pretty much anything. (Annoyingly
fast for those who want to contain it, at least.)
I suspect it also depends on how much getter function is left. The
getter's whole point is to capture stray bits of gas; as long as it
lasts, it'll be scavenging up any stray molecules that do find their
way in. I suspect internal outgassing is more significant than
diffusion through the body of the thing, in most cases, though.
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