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In Reply to: Re: Have you looked at your 211's....? posted by Dave-A on July 7, 2006 at 19:34:51:
You posted giving some information which is contrary to the information in all the sources I have read*.This means it is either new to me (and very interesting) or wrong. I'd like to know which.
I'm leaning towards wrong because you have offered no supporting evidence and your follow up doesn't make sense - there is no nickel on the filaments of my 211s, they operate at too high a temperature for any nickel alloy or salt (including the oxide) to survive. Although monoatomic layers of emissive materials can survive above their bulk melting points (this is the basis of the action of thorium) it makes no sense to do this with nickel as the work function is higher than that of tungsten.
If you can support your claim I'll be the first to acknowledge that you have brought some new information.
*The only reference to emission from nickel that I can find is a graph in Spangenberg's "Vacuum Tubes" which shows that the emission efficiency of a nickel filament peaks at around 0.2 (roughly half of pure tungsten, the least efficient emitter in normal use) and that's at a dangerously high temperature of around 1400 C, very close to the melting point of nickel.
Mark Kelly
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Follow Ups
- I'm not picking nits. - Mark Kelly 20:18:26 07/07/06 (5)
- Re: I'm sorry I forgot about the drains... - Dave-A 21:09:14 07/07/06 (4)
- Now I see the problem - Mark Kelly 23:06:23 07/07/06 (3)
- Re: Another example - Dave-A 06:27:29 07/08/06 (2)
- Just for consistency - Mark Kelly 16:11:40 07/08/06 (1)
- Re: Just for my understanding... - Dave-A 09:34:21 07/09/06 (0)
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