Date: Tue, 01 Nov 94 08:28:31 pst
Subject: Re[2]: xray mapping
From: "michael shaffer"

Hi John,

The gist I get from Dana Johnson is that he'd like to measure boron
in granitic melts -- personally, I have no experience with what levels
he might find, and I don't think he knows exactly either. I did get a
chance to speak with David London at GSA, and he implied measurements
of 0.4wt% with a PC2, and that he wanted to change over to a PC3
because of an obtrusive satellite peak. I think he may have another
type of problem as I can't imagine a different xtal getting rid of his
problem -- altho the dispersion might be different. Regarding
sensitivity, I noticed the ODPB xtal can see boron in the 2theta range
which typically offers good dispersion and actually has a higher S/N
ratio than any of the PC xtals. What is the problem with ODPB???

Let me know what you think, and thanx again.

Michael shaffer, RA


______________________________ Reply Separator _________________________________
Subject: Re: xray mapping
Author: johnf@geology.wisc.edu at gateway
Date: 11/01/94 09:50 AM


Michael:

Thanks for the info on the xray mapping. George Morgan from U of OK is
going
to be here in a couple of days so I'll ask what they did there.

Re: Boron. We have an LPC3 for Be and B. We have done a little work with
the PC crystals and see their limitations. The main one is that the peaks
are _very_broad and thus can overlap with long wavelength multiple order
reflections, L lines, etc. (Of course, the corrections can be large)

What level are you looking at? If you want to send something to me to check
out, no problem.
\
john

John Fournelle
Electron Microprobe Lab Internet:johnf@geology.wisc.edu
Dept of Geology & Geophysics Telephone: (608) 262-7964
University of Wisconsin Fax: (608) 262-0693
1215 West Dayton Street Amateur radio: WA3BTA/9
Madison, WI 53706