[Amps] 2 ways of Gettering...
Fuqua, Bill L
wlfuqu00 at uky.edu
Tue Sep 13 22:20:45 PDT 2011
High vacuum systems use getters that get very hot, but they slowly evaporate over a very long time, years sometimes.
The metallic vapor collides with the gas molecules and they both become deposited on the walls of the iion pump.
Heating the surfaces (bakeing) drives off the gas molecules that are pumped by the these ion pumps.
To increase the chances of collisions magnets are used to increase the path that the ions take before they collide
with the walls. Hot is good in this case.
From: amps-bounces at contesting.com [amps-bounces at contesting.com] On Behalf Of Carl [km1h at jeremy.mv.com]
Sent: Tuesday, September 13, 2011 5:32 PM
To: jtml at vla.com; amps at contesting.com
Subject: Re: [Amps] 2 ways of Gettering...
----- Original Message -----
From: "John Lyles" <jtml at losalamos.com>
To: <amps at contesting.com>; <amps at contesting.com>
Sent: Tuesday, September 13, 2011 3:40 PM
Subject: [Amps] 2 ways of Gettering...
> Actually the getter is there all the time and what you are speaking about
> is how to reactivate the gettering process.
> By heating "some" metallic getters such as coated plates, they attract
> more ions and molecules of gas in vacuum device. Running the plate with
> is risky in itself as it may liberate additional molecules from the plate
> which then have to be absorbed. Some tubes may be
> worsened after this process.
But this doesnt apply to the ham type tubes in service today. A 3-500 doesnt
outgas at a red color and I havent found any decrease in a hi-pot even after
an extended bright orange.
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