On Sunday, 19 May 2019 23:45:14 UTC+1, Cursitor Doom wrote:
On Sun, 19 May 2019 13:24:18 -0700, tabbypurr wrote:

You can eliminate all those with glass, vacuum & getter. Then you find
one day that the getter is oxidised & the bulb contains hydrogen.

I was under the impression that glass was impermeable even to omnipresent
hydrogen. Or is there a path via where the base pins protrude?

Glasslinger did a mass spec analysis to discover that gassy valves contain hydrogen. I don't know whether that permeates through the glass (unlikely since most valves stay hard), leaks in through pin sealing defects or is the result of remaining water vapour reacting with the getter. Either way a getter that could capture it would be a good thing probably.

https://www.youtube.com/watch?v=16vOoF_XUB8


NT