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*

Alfred,
     The biggest problems with using the Li borate fusion technique  
are that precisions are greatly reduced and the sample is much more  
easily beam damaged.
eric


On Apr 5, 2007, at 10:27 AM, Alfred Kracher wrote:

> JEOL Probe Users Listserver
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> Moderator: Ellery Frahm, [log in to unmask],
> Electron Microprobe Lab, University of Minnesota
>
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> *
>
> Hello Ron,
>
> At 4/4/2007 11:23 PM, you wrote:
>> When is it possible to do a quantitative analysis on a probe with a
>> rastered beam on an inhomogeneous sample?
>
> I sometimes use a defocussed beam, but for the reason mentioned by  
> Andy Buckley I stay away from rastering. The JEOL 8200 has a "beam  
> diameter" parameter in its EOS setup, which is fairly accurate  
> judging from materials that show the "burn" spot.
>
> Right now I am engaged in a quantitative study how well that works  
> for various alloys. One thing I am still missing is a probe that  
> would allow me to measure the beam intensity across a defocussed  
> beam, although I think it will be more uniform than across a raster.
>
> Many years ago we also tried Li-borate fusion for rock analysis (on  
> samples too small for our XRF), which seemed to work o.k., but  
> didn't pursue it past the initial tests.
>
> Alfred
>
> Alfred Kracher
> Ames Laboratory (USDOE)
> Iowa State University
> 227 Wilhelm Hall
> Ames, IA 50011-3020
> Tel.: 515 294 7097
>
>