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Electron Microprobe Lab, University of Minnesota

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*

Henry,
     One can see reaction to the electron beam in apatite by the loss  
of CL, evidence of physical damage even with a scanning beam, and  
orientation-dependent migration of halogens that was well documented  
by Stormer et al. (1993, Am. Min.).  We have confirmed Stormer's  
observations in our lab.  I would recommend a 5 micron scanning beam  
at 5 nA and 15 kV for apatite analyses.
eric


On Sep 6, 2006, at 3:01 PM, Henry Barwood wrote:

> JEOL Probe Users Listserver
> Moderator: Ellery Frahm, [log in to unmask], Electron Microprobe Lab,  
> University of Minnesota
>
> Post a message: send your message to [log in to unmask]
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> *
> Dear Eric,
>
>
>
> Thanks. I had not noticed significant beam damage in my apatites,  
> but then Iím a (very) modest user of the probe. I do usually try  
> and use as large a spot size as possible. Some phosphates are  
> significantly degraded under the beam no matter how careful you are.
>
>
>
> Henry
>
>
>
> Henry Barwood
>
> Associate Professor of Science, Earth Sciences
>
> Department of Math and Physics
>
> MSCX 312G
>
> Troy University
>
> Troy, Alabama
>
> [log in to unmask]
>
>
>
> From: JEOL-Focused Probe Users List  
> [mailto:[log in to unmask]] On Behalf Of Eric J Essene 1
> Sent: Wednesday, September 06, 2006 12:02 PM
> To: [log in to unmask]
> Subject: Re: [PROBE-USERS] Help with probe analysis of minerals
>
>
>
> Henry,
>
> Microprobe analysis of both the apatite- and bastnaesite-group  
> phases is quite touchy. Beam damage, degassing and elemental  
> migration (potential F and Cl increase in apatite with time) are  
> significant problems for these minerals.
>
> eric
>
>
>
>
>
> On Sep 6, 2006, at 11:52 AM, Henry Barwood wrote:
>
>
>
>
> JEOL Probe Users Listserver
>
>
>
> Moderator: Ellery Frahm, [log in to unmask],
>
> Electron Microprobe Lab, University of Minnesota
>
>
>
> Post a message: send your message to [log in to unmask]
>
>
>
> Unsubscribe: send "SIGNOFF PROBEUSERS" to [log in to unmask]
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>
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> On-line help and FAQ: http://probelab.geo.umn.edu/listserver.html
>
>
>
>
>
>
>
> *
>
>
>
> Perhaps someone on the list would be interested in collaborating  
> with me on
>
> the analysis of some mineral specimens for publication. I have been
>
> conducting studies of syenite minerals from the Arkansas alkalic  
> syenites
>
> for over 20 years and would like to work on some of the  
> accumulation of
>
> unknowns that has built up. Unfortunately, here at Troy, my research
>
> capabilities are somewhat limited. If there is anyone who would  
> like to
>
> analyze some of the specimens as a co-author, please let me know.  
> Some of
>
> the partially completed studies that I have waiting include:
>
>
>
> Analysis of brithiolite and silician fluorapatites
>
> Mosandrite analysis
>
> Examination of the eudialites from Magnet Cove and Jones Mills
>
> Reexamination of the rare-earth fluorocarbonates from several  
> locations
>
>
>
> Thanks.
>
>
>
> Henry Barwood
>
> Associate Professor of Science, Earth Sciences
>
> Department of Math and Physics
>
> MSCX 312G
>
> Troy University
>
> Troy, Alabama
>
> [log in to unmask]
>
>
>
>
>
>
>
>
>