Used ionization gauge looks burnt out?

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RobertMendelsohn
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Real name: Robert Mendelsohn

Used ionization gauge looks burnt out?

Post by RobertMendelsohn »

Hello,

I am looking to buy an apparatus that includes this used hot filament ionization gauge (picture attached). It seems a bit burnt out, and seems to be missing the silvery getter typical of these gauges.
Does this look OK to the veteran ion gauge users on this forum, or should I plan on replacing it? Only use will tell, but I would appreciate any advice/opinions/speculations anyone has.

Sincerely,

Robert
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Maciek Szymanski
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Re: Used ionization gauge looks burnt out?

Post by Maciek Szymanski »

It's hard to see on the photo if the filament is burned or not. But as long as the filament is not damaged the gauge should work. The deposits on the glass envelope are normal especially if used with oil pumps. I never seen the bayard-alpert gauge with a getter. Do not forget to outgass the gauge before taking the readings, one that was exposed to the air for a long time may be miss-reading by few orders of magnitude until properly outgassed.
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Richard Hull
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Re: Used ionization gauge looks burnt out?

Post by Richard Hull »

Likwise no Getter in an ion gauge. Sealed vacuum tubes, yes. I'll go along with Maciek, I am not able to determine by the image you provide if the filament is intact. The normal reason ion gauges are found loose is burned out fils.

Richard Hull
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RobertMendelsohn
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Joined: Mon Jul 20, 2020 4:58 pm
Real name: Robert Mendelsohn

Re: Used ionization gauge looks burnt out?

Post by RobertMendelsohn »

Thank you all! Yes, it now makes sense that a gauge would not have a getter, since it would be regularly brought up to atmosphere. I'm going to take a gamble on it. Thanks again.

Sincerely,

Robert
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Dennis P Brown
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Re: Used ionization gauge looks burnt out?

Post by Dennis P Brown »

As I tell anyone buying electronic equipment; if the seller allows returns (two weeks min.) then its worthwhile considering; if not, don't ever buy from them. Of course, ask if tested and/or working. Not that that is essential if they allow returns. Testing is simple (even w/o vacuum.) Use an ohm meter for continuity on the filament. Note how it couples to the vacuum system - that appears to use copper gaskets (but can be converted to 0-ring use.) Many ion gauges have two filaments (one is a backup) - both should work.
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