Recent Posts

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As many of you know, a distribution of Penepma 2012 is included for use with the Penepma GUI in the Standard program.

Recently we completed modeling the pure elements from Li to Cm at electron beam energies from 5 to 30 keV in 5 keV steps utilizing 1 eV bins for fine spectral details. These pure element spectra are used by Probe for EPMA to create synthetic WDS spectra as described here:

https://probesoftware.com/smf/index.php?topic=837.msg9198#msg9198

Also note that the spectra for Li, be and B were calculated utilizing Penepma 2016 which is not normally distributed, but see the previous two posts in this topic for instructions on downloading Penepma 2016 to your computer which can then be utilized with the Standard Penepma GUI.

Finally, once you are updated to the most recent Penepma distribution, the "pe-spect-01.dat" and "pe-intens-01.dat" files for each pure element are stored in these folders shown here:



To download the most recent version of the Penepma 2012 distribution, simply use the "Update Penepma Monte-Carlo Files Only" check box from the CalcZAF or Probe for EPMA Help menus as shown in this post:

https://probesoftware.com/smf/index.php?topic=366.msg1936#msg1936
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Probe for EPMA / Re: Wish List for PFE Features
« Last post by John Donovan on November 24, 2020, 07:40:04 AM »
So it fits a function to the whole wavescan range is that right?

So Parabolic and Gaussian only work if wavescan range is restricted to the width of the peak, whereas Brent Maxima always works, as its using a parabolic interpolation to find the maxima -

Hi Ben,
Yes I noticed that also.

We will try to modify the fitting code to only utilize the current "zoom" range.  Give us a few days.
john
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Probe for EPMA / Re: Mineral formula calculations
« Last post by Joseph_Shaw on November 24, 2020, 05:37:48 AM »
Hi John,
You are right - the crystals are very easily damaged. Unfortunately the samples are fine grained (generally sub-10 microns), with voids between grains. We have been getting reasonable results with a 2 micron, 3nA beam and applying a TDI correction.
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Probe for EPMA / Re: Wish List for PFE Features
« Last post by Ben Buse on November 24, 2020, 04:05:53 AM »
Hi John,

Thanks, you learn something new everyday.

So it fits a function to the whole wavescan range is that right?

So Parabolic and Gaussian only work if wavescan range is restricted to the width of the peak, whereas Brent Maxima always works, as its using a parabolic interpolation to find the maxima -

Thanks

Ben
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Discussion of General EPMA Issues / bcr2-g sulphur composition
« Last post by Ben Buse on November 24, 2020, 03:52:24 AM »
Hi,
I was looking for standard values for sulphur in bcr2-g

Any ideas?

GeoRem quote 3 papers - 20-40ppm, one of which ICPMS, the others EPMA with large errors.

Whereas Agnès Michel and Benoît Villemant have 158-165, although this may be the rock rather than the glass
https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1751-908X.2003.tb00643.x

And Xu-Jie Shu and Cin-Ty A. Lee have 159 ppm for the glass



Thanks

Ben
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Probe for EPMA / Re: Wish List for PFE Features
« Last post by John Donovan on November 23, 2020, 09:39:34 AM »
Hi Ben,
Well, you can either uncheck the "Relative Position" checkbox in the Plot! window and use the mouse cursor to display in spectrometer units, as shown here:



Or you can use one of the peak fitting methods in the Model Backgrounds dialog as seen here:

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Probe for EPMA / Re: Wish List for PFE Features
« Last post by Ben Buse on November 23, 2020, 07:09:40 AM »
Hi John,

We often use the wavescan function to identify the peak position for S on vg2, with ca. 1000ppm,

Would it be difficult to have a peak fitting function - to read the peak position within the plot window?

Thanks

Ben
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Discussion of General EPMA Issues / ARL Probe News and other old newsletters
« Last post by JohnF on November 22, 2020, 04:40:50 PM »
History: "The past is never dead. It's not even past."--Hemingway

I am the archivist of the Microanalysis Society (formerly Microbeam Analysis Society and back in the ancient times, the Electron Probe Analysis Society of America) and recently in sorting through old files left by my predecessor Everett Glover (1917-2017), I came across a page cut out of “ARL Probe News, a quarterly newsletter published by Applied Research Laboratories’ Research Instruments Product Group, Stephen O. Friend, Editor”. By any chance, does anyone happen to have any copies of this newsletter, which they would be willing to donate to the MAS Archives? (We will be installing our archives at the Science History Institute in Philadelphia in 2021.) Or if you have any other historical materials from the 1960s onward that document our field (newsletters, correspondence, white papers, etc).

Thanks.

John
johnf@geology.wisc.edu
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EPMA Laboratory Planning and Design / Re: humidity control
« Last post by Mike Jercinovic on November 21, 2020, 07:55:44 AM »
Thanks for the info Anette.  We tried a stand alone humidifier too, not even close to keeping up in our case, and filling constantly like you say.
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EPMA Laboratory Planning and Design / Re: humidity control
« Last post by Anette von der Handt on November 20, 2020, 06:51:02 PM »
I was told (and had specified for my lab) that keeping humidity between 30% and 60% as the target. Of course the architects of our building nodded and then did nothing (because it is expensive or they just didn't care),. So now my lab has no humidity control and I often have a humidity of 10% in the dry Midwest winter and feel I need to drink gallons of water besides getting shocked often. On the upside, the machine reaches a good vacuum in no time after sample change :)

I had bought the largest stand-alone humidifier I could find but it would only raise the humidity by 5% (large lab though) and made a giant ruckus and needed to be refilled constantly so I eventually gave up on it. To get proper humidity control, I was told I need to tap into the steam system which was too expensive. A different lab in the building did that though and now they have controlled humidity but the controllers in their hallway generate so much heat that the heat load is causing other problems for them.

I have dissipative flooring though, so it could be worse. I also got these 5$ anti-static key chain eliminators that you can find on Amazon/ebay.

Would be interested to learn if there are other solutions. Obviously it depends strongly on the humidity range in the region how difficult it is to maintain within a range.
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