On Jan 16, 2006, at 3:55 PM, gdaught6@stanford.edu wrote:
> Hi all,
>
> A few days ago, someone asked "where is the getter on a thoriated
> tungsten filament tube?" [as opposed to an oxide cathode tube...]
>
> I just spent the morning with an expert in rebuilding of thoriated
> tungsten filament tubes, and asked him that exact question. He told
> me "it depends on the tube." Then he showed me a few examples: one
> type was a small disc (zirconium) near the base of the filament
> support pedestal; another was a zirconium wire helically wound on a
> molybdenum pedestal at the center (coaxial with) of the filament
> structure. He told me "it's almost always zirconium, because that
> stuff LOVES to mop up gases, especially oxygen."
George -- What gettering material is use to mop up nitrogen?
>
> Then came what I consider very important knowledge:
>
> "The getters are heated by their proximity to the filament structure.
> That's why you should run the tubes at the full rated filament
> voltage for about a hundred hours. Then you can reduce the filament
> voltage a bit while still maintaining the desired output."
>
> 73,
>
>
>
>
> George T. Daughters, K6GT
>
>
>
>
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>
>
Richard L. Measures, AG6K, 805.386.3734. www.somis.org
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