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Dear Mr. Midwood,
many years ago I worked with ion pumps in stable isotope gas MS.
Normally they clean itself, if they become really hot.
For that purpose you must increase the pressure. The higher ioncurrent will heat the pump.
Do it at least for one hour.
After that, it should be ok. Cleaning of the pump by other methods is not possible, at least to my
knowledge.

Regards,

Stephan Hoernes

On Fri, 12 Nov 1999 09:51:44 -0000, Andy Midwood wrote:

>Dear List Members -
>
>
>I'm looking for advice on Ion pumps.
>
>
>The source ion pump our VG354 thermal ionisation mass spec appears to have
>
>partially stopped working, leaving the vacuum just below 10-6 mBar. I've
>
>baked out the system with no improvement. The pump controller is common to
>
>a smaller ion pump on the analyser bench which appears to be working
>
>correctly so I suspect the actual pump itself. There are also worrying
>
>flickers on the meter of the power supply if we monitor the current being
>
>drawn by the pump.
>
>
>Does anyone know if the pump can be dismantled and cleaned ?
>
>Any advice on dealing with this type of problem would be gratefully
>
>received !
>
>
>Thanks
>
>Andy Midwood
>
>
>
><nofill>
>___________________________________________________
>
>Dr Andy Midwood,
>Analytical Group,
>Macaulay Land Use Research Institute,
>Craigiebuckler,
>ABERDEEN,
>AB15 8QH,
>UK
>
>Tel: +44 (0) 1224 318611
>Fax: +44 (0) 1224 311556
>
>Email: [log in to unmask]
>http://www.mluri.sari.ac.uk


*******************************************************
Prof. Dr. Stephan Hoernes
Mineralogisch-Petrologisches Institut
Poppelsdorfer Schloss
D-53115 Bonn
Germany
Tel: (0)228 73 2733 Fax: (0)228 73 2763
E-Mail: [log in to unmask] or:
               [log in to unmask]
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