Recent Posts

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Probe for EPMA / Re: Z-focus on rectangular grids
« Last post by John Donovan on October 18, 2017, 09:59:13 pm »
OK, I see the issue.  Z-interpolation for the rectangular grid would be useful, however.  Perhaps, you could use the X-Y positions of UL/LR to choose either UR/LL, drive the stage to one of those position, focus Z and then use the polygon feature to fit a plane and interpolate Z.

Thanks!

Hi Rick,
That's a good idea. 

I'll have it default to one of the other corners with the current Z, but also allow the user to update that third point to something different, just in case that corner is not good for stage focusing.
john
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Probe for EPMA / Re: Z-focus on rectangular grids
« Last post by Falling Man on October 18, 2017, 08:44:41 pm »
OK, I see the issue.  Z-interpolation for the rectangular grid would be useful, however.  Perhaps, you could use the X-Y positions of UL/LR to choose either UR/LL, drive the stage to one of those position, focus Z and then use the polygon feature to fit a plane and interpolate Z.

Thanks!
3
Probe for EPMA / Re: Z-focus on rectangular grids
« Last post by Probeman on October 18, 2017, 08:03:00 pm »
I'm running PFE on a JEOL 8200 and setting up analyses on a rectangular grid.  The "Start" and "Stop" positions have different Z-axis positions.  However, when PFE calculates the Z position for the points on the grid it uses the value for the "Stop" point and assigns that to all of the points on the grid.  As such, most of the points, with the exception of "Stop" are out of focus.  Has anyone seen this problem?  Solutions?

Hi Rick,
You are correct.  The two point rectangular grid assumes the current position for all z values. 

The Z position interpolation works for the traverse because two points define a line, though not a plane. But we probably could make an assumption about the slope of the plane and interpolate the Z positions when the Z positions of the two rectangular corners are different.

In the meantime just use the polygon grid dialog in the Digitize window. Define 4 points for a rectangle (at least three or more for any shape polygon) and the app fits either an average Z position or plane fit interpolated Z for all Z positions.
john
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EPMA Laboratory Management / Re: EPMA Positions Open
« Last post by Julien on October 18, 2017, 07:19:42 pm »
Dear microprobe community,

I have recently accepted a lab manager position at the ETH Zurich in Switzerland, and therefore the Electron Microprobe Lab at the University fo Colorado Boulder will soon need a new manager (Research Associate) for the JEOL-8230 by Spring 2018. Ideal candidate should be a motivated scientists with knowledge of Probe for EPMA and with interest in trace element analysis by EPMA and in analyzing beam sensitive material (carbonate, phosphate, hydrated sulfateā€¦). More information about the lab available here: http://geode.colorado.edu/~jallaz/index.php?page=microprobe

There is no official ad to share yet but it will be coming very soon. However, Kevin Mahan, the lab director, will be at the GSA meeting in Seattle next week (October 22-25, 2017) if anyone interested would like to talk more about this position. Please send Kevin an email separately to Kevin.Mahan@colorado.edu to arrange something. Otherwise, please look for the ad coming soon!
 
Julien & Kevin
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Probe for EPMA / Z-focus on rectangular grids
« Last post by Falling Man on October 18, 2017, 06:23:05 pm »
I'm running PFE on a JEOL 8200 and setting up analyses on a rectangular grid.  The "Start" and "Stop" positions have different Z-axis positions.  However, when PFE calculates the Z position for the points on the grid it uses the value for the "Stop" point and assigns that to all of the points on the grid.  As such, most of the points, with the exception of "Stop" are out of focus.  Has anyone seen this problem?  Solutions?
6
A student in our geology department, David Zakharov, has an interesting blog on petrography called, appropriately enough, "The Petrographer":

http://opticalmineralogy.blogspot.com

He recently wrote some scripts to output chemical maps without Surfer:

http://opticalmineralogy.blogspot.com/2017/10/automated-petrography-electron.html

john
7
I recently modified the scripting output code to set the "Project Folder" for Surfer, to the folder of the currently open CalcImage project, when a Surfer script is being output.  This is done by editing the registry settings for the Surfer application "Project Folder".

The practical  benefit is merely that when running a "slice" or "polygon" feature extraction script, when the user clicks the Save As menu for the digitized slice or polygon outline, as seen here:



Surfer will now open the current CalcImage project folder by default.  As opposed to having to browse to the correct project folder manually.  Please update to 12.0.1 and you will obtain this small improvement to the CalcImage script processing in Surfer.
john
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Discussion of General EPMA Issues / Best CL imaging techniques
« Last post by Probeman on October 14, 2017, 10:13:33 am »
Although obviously it will depend significantly on the sample, I'm wondering in general what beam conditions and imaging parameters will produce the most sensitive high resolution panchromatic CL images. For example I seem to see on both my Cameca SX100 and FEI Quanta SEM that slowing down the beam scan does reduce the pixel to pixel noise. But if the beam (or stage) scan is very slow, the intensity of the CL output seems to be reduced. 

I recently took some video images on my Sx1200 and the images were OK, but the slowest scan speed on the Cameca video system is speed 7, which depending the image size is roughly a 60 sec frame time.  That means the pixel dwell times were roughly 1 msec per pixel.

Switching to the mapping system I then ran some CL stage scans using 100 msec pixel dwell times and I was quite disappointed with the CL image quality. 

I can understand that as the scan speed is reduced, the sample (recently I've been looking at quartz with some geologists) will experience greater beam damage, but I also wonder if one can "saturate" the CL emission by keeping the outer electron shells excited with enough electron flux?

Does it make any sense that slower beam (or stage) scans will result in less CL output?  I'm also wondering what combination of beam conditions and imaging parameters do others use to get good quality panchromatic CL images?
john
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We recently released v. 12.0.1 of Probe for EPMA.   

The main features of this new release are integrated support for JEOL EDS systems (8230/8530) for quant integration of EDS and WDS using full k-ratios and standards for optimum accuracy, and also GUI improvements which will allow better scaling when running on high resolution monitors (e.g., 4K) and also for non-default DPI settings (e.g., for teaching and demonstration).
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Probe for EPMA / Re: Quant Analysis of Carbon Using MAN backgrounds
« Last post by BenjaminWade on October 11, 2017, 06:32:45 pm »
Yes I did think about it, but I stuck with the PC0 as the F content is quite low, usually less than 500ppm or so. So thought I might be better off with the higher count rate on PC0 and less interferences? In hindsight I guess I should have probably tried it out anyway.
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