JEOL Probe Users Listserver
Moderator: Ellery Frahm, [log in to unmask],
Electron Microprobe Lab, University of Minnesota
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First of all. There is a description of analysis methods in the ISO
Standard 14594, "Microbeam analysis- Electron prope microanalysis-
Guidelines for the determination of experimental parameters for
wavelength dispersive spectroscopy".
It will give basic but important points of view how to make the
procedure. Not detailed things but basics, and they should be
followed, there has been a lot of epma-specialists all around the
world preparing this "compromise".
University of Oulu
institute of Electron Optics
At 05:49 4.6.2008, you 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]
>On-line help and FAQ: http://probelab.geo.umn.edu/listserver.html
>I am working on a project that attempts to evaluate the effects of
>choices made in EMPA on the data and ultimately on the geological
>interpretations. I want to analyze a set of geological specimens
>using three, four, maybe five analytical schemes, and I'll see how
>those different schemes affect the data and ultimate interpretations.
>Two or three of these schemes will be based on common approaches in
>the relevant literature. The main goal is essentially to determine
>the robustness of the geological interpretations. Can these
>interpretations withstand variations introduced by different
>analysts? Are the ultimate interpretations vulnerable to the
>different "cultures" or analytical "traditions" of different labs?
>Analysts carry out a series of actions and make a series of choices
>while doing an analysis. This is considered an "operational sequence"
>by anthropologists who study technology, and such anthropologists are
>interested in the choices people make and the reasons for those
>choices. Some of these choices, even in EMPA, are made for very
>technical and logical reasons (e.g., an accelerating voltage of 15 kV
>optimizes the overvoltage ratio for the main elements of interest),
>whereas other choices are made for outdated, arbitrary, or other
>reasons (e.g., we use Correction Method A, not Correction Method B, in
>this lab because it is what we've always done). Both types of choices
>can be equally important in obtaining accurate data.
>Back to my research project, I have ideas about what choices are most
>important and common in EMPA when deciding how to analyze a geological
>specimen. But I'd like to not bias my project by investigating only
>my own ideas about important and common choices. I haven't spent very
>much time in other microprobe labs, so I am embedded in the "culture"
>of the lab here at the University of Minnesota.
>So I'd like to hear from my colleagues on this issue. What do you
>think are the most important and common choices made when approaching
>an analysis? Are there choices that you think almost all of your
>colleagues would make the same way? Have researchers from other labs
>asked you to use conditions that boggle you? If you have spent a lot
>of time in multiple labs, have you recognized the different "cultures"
>of the labs? What choices do you think analysts make that aren't
>really important today but are based on habits or traditions from
>older machines or correction routines? I will use any comments and
>criticisms I receive to select the choices on which this project
>should focus, probably just by tabulating the responses.
>I apologize for being a bit vague, but I'm trying not to bias anyone's
>responses. I welcome all input and opinions either on- or off-list.
>All comments or criticisms will remain anonymous unless you either
>respond on-list or give me explicit permission to cite you.
>Thank you for your time and assistance. I apologize if you have
>received this email more than once due to cross-list posting.
>Ellery E. Frahm
>Research Fellow & Manager
>Electron Microprobe Laboratory
>University of Minnesota - Twin Cities
>Department of Geology & Geophysics
>Lab Website: http://probelab.geo.umn.edu
>Personal Website: http://umn.edu/~frah0010