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

tel.: +32 (0)9 264 6048
fax.: +32 (0)9 264 6230

"I have not failed. I've just found 10000 ways that won't work"
- Thomas Alva Edison (1847-1931)

-----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.