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Dear Anthony,

I would like to try helping you with your beam focussing problem, but there
are some things that I should know before I can say something:

- What happens if you raise the beam focus again after it drops? Does it
stay fixed or does it raise along according to how you set it?
- Is it possible that the beam focus is ok, but the software is not
following? I have had the problem sometimes that when I raised the beam
focus, saved the source file and the reloaded it, some funny beam focussing
numbers appeared.
- How do your beam signals look like (compared for example with when you
didn't have this problem)?
- Is only the beam focus acting strange, or do you have other source
parameters doing weird things?

Best regards,

Peter



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Peter Vervloedt
Laboratory of Applied Physical Chemistry
Faculty of Agricultural and Applied Biological sciences
Ghent University
Coupure, 653
9000 Gent
Belgium

tel.: +32 (0)9 264 6048
fax.: +32 (0)9 264 6230
http://fltbwww.rug.ac.be/isofys

"I have not failed. I've just found 10000 ways that won't work"
- Thomas Alva Edison (1847-1931)
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-----Original Message-----
From: Stable Isotope Geochemistry [mailto:[log in to unmask]]On
Behalf Of Anthony Michaud
Sent: Thursday, January 18, 2001 10:32 PM
To: [log in to unmask]
Subject: [ISOGEOCHEM] Europa 20/20 beam focus


Hello all. I'm using a Europa 20/20 and am having problems with the beam
focus. Here is a description of the problem:

- In all of the following situations the beam focus was set to 87%.

When the HT is set to 4000V, the beam focus goes to 30%.
When the HT is set to 3000V, the beam focus goes to 54%.
When the HT is set to 2000V, the beam focus goes to 65-67%.
When the HT is set to 1000V, the beam focus goes to 86%.
When the HT is set to 0V, the beam focus goes to 50%.

I am hoping that somebody out there has had this problem before and knows
of a quick fix so that I don't have to wait until tomorrow to get help from
tech support.

Thanks!

Anthony