Date: Mon, 11 Oct 93 15:35:14 CDT
Subject: Re: SX50 Users and Auto xyz routine
From: "Ray Guillemette"

Dear John,
Thanks for the info on the progress of forming an SX50 Users Group. As I
indicated to you earlier, I'd be very much interested in participating in such a
group. I don't have any major suggestions on how to go about forming a users
group. On the question of sharing new software contributions among SX50 users,
we might consider setting up anonymous FTP servers on our SUNs, and placing any
such software that we might have in our respective pub FTP directories. Each of
us could periodically e-mail a note to all other members of the users group
informing them of our contributions, notes, etc. and inviting them to connect
and transfer files that might interest them. Or, we might make some arrangement
with MAS to see if we could add our contributions to an SX50 directory at their
FTP site.
In regard to your question about generating x & y information from images
generated on the SX50: I've been doing this myself in a couple of different ways
for about a year now. I've appended a Stuffed, Binhexed Mac MSWord 4.0 document
that summarizes the steps necessary to process an image and generate the
automatic xyzpos.dat file.
Briefly, I've been using this procedure to pick out zircons in heavy-mineral
separates and to analyze those zircons. I've tried both x-ray and BSE images,
and have found the latter to almost always be far preferable; I can use shorter
acquisition times and lower beam currents to mininmize volatile generation from
epoxy-potted grain mounts, and the quality of the grain outlines is better.
I've also experimented with the procedure for quartz-feldspar-amphibole
mixtures, and BSE discrimination also worked well here, provided the sample was
thoroughly polished over the entire surface (especially important for cases
where the area scanned is a centimeter or larger, where differences in quality
of polish cause variations in BSE signal intensity from one area of an image to
another)
After using this procedure to generate the xyzpos.dat file, I've found it
crucial to review each stored position using the updpos program (update
points/lines in the analysis menu). This program may not be present on your
version of software; Cameca eliminated it from the menu about two versions ago,
but I found it so useful that I recovered from my old backup tapes. Let me know
if you need more information on it. This quick poiny-by-point review helps you
to avoid cracks, internal pits, etc.
I've recently been working to apply the visilog xyz method to SEM images of
grains on adhesive surfaces. Here, I've been trying to use Quantiview in
EDS-only mode for qualitative applications.
Good luck, and let me know if you run into any problems.
Regards,
Ray




Dr. Renald N. Guillemette (rng5840@geopsun.tamu.edu)
Electron Microprobe Lab
Dept. of Geology
Texas A&M University
College Station, TX 77843-3115



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