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CalcZAF and Standard / Re: Fast and Easy Modeling of Matrix Corrections in Standard.exe (Penfluor/Fanal)
« Last post by Probeman on February 23, 2021, 03:22:27 PM »The latest release of CalcZAF includes the most recent matrix.mdb k-ratio database, which now contains over half a million (565K) k-ratio intensities. This database can be found in the C:\ProgramData\Probe Software\Probe for EPMA folder.
The matrix.mdb is a Microsoft Access (2000) relational database which contains k-ratio intensities calculated from binary compounds and pure elements from Penepma (Penfluor/Fanal). These binary compositions range from 1% to 99% with 11 compositions per binary for electron beam energies between 5 and 50 keV for elements carbon to californium. More details are found in this topic above. For calculations using the full Penepma code see here:
https://probesoftware.com/smf/index.php?topic=151.0
There are a number of benefits to these intensity calculations, the primary one being that the Penepma code is not "tuned" to a particular dataset, as is the case for the analytical expressions that we normally utilize in our matrix corrections. These intensity calculations are purely based on the best quantum mechanical models (and fundamental parameters) available at the time.
So one possible use of this intensity database could be in comparing these "untuned" calculated intensities with calculations from our analytical expressions, and note where we see significant discrepancies, which we could possibly resolve through empirical measurements.
In addition this matrix.mdb database is also utilized for matrix corrections in Probe for EPMA (and CalcZAF) by fitting the intensities to hyperbolic expressions via so called "alpha factors". This is described in more detail here in the forum:
https://probesoftware.com/smf/index.php?topic=47.0
And also in a paper published by Donovan, Pinard and Demers which describes this method in detail here:
https://epmalab.uoregon.edu/publ/high_speed_matrix_corrections_for_quantitative_xray_microanalysis_based_on_monte_carlo_simulated_kratio_intensities.pdf
The main takeaway from the above work is that the alpha factor method works quite well, except in cases of extreme fluorescence, so in some instances where the analytical expressions fail, this method might be somewhat useful.
On a more adventurous note, it might also be interesting to attempt to utilize this database of k-ratio intensities to train a neural net. However, the database is still incomplete with some areas of the periodic table still being calculated. But if someone is interested in pursuing this line of inquiry, I'd be pleased to participate.
The matrix.mdb is a Microsoft Access (2000) relational database which contains k-ratio intensities calculated from binary compounds and pure elements from Penepma (Penfluor/Fanal). These binary compositions range from 1% to 99% with 11 compositions per binary for electron beam energies between 5 and 50 keV for elements carbon to californium. More details are found in this topic above. For calculations using the full Penepma code see here:
https://probesoftware.com/smf/index.php?topic=151.0
There are a number of benefits to these intensity calculations, the primary one being that the Penepma code is not "tuned" to a particular dataset, as is the case for the analytical expressions that we normally utilize in our matrix corrections. These intensity calculations are purely based on the best quantum mechanical models (and fundamental parameters) available at the time.
So one possible use of this intensity database could be in comparing these "untuned" calculated intensities with calculations from our analytical expressions, and note where we see significant discrepancies, which we could possibly resolve through empirical measurements.
In addition this matrix.mdb database is also utilized for matrix corrections in Probe for EPMA (and CalcZAF) by fitting the intensities to hyperbolic expressions via so called "alpha factors". This is described in more detail here in the forum:
https://probesoftware.com/smf/index.php?topic=47.0
And also in a paper published by Donovan, Pinard and Demers which describes this method in detail here:
https://epmalab.uoregon.edu/publ/high_speed_matrix_corrections_for_quantitative_xray_microanalysis_based_on_monte_carlo_simulated_kratio_intensities.pdf
The main takeaway from the above work is that the alpha factor method works quite well, except in cases of extreme fluorescence, so in some instances where the analytical expressions fail, this method might be somewhat useful.
On a more adventurous note, it might also be interesting to attempt to utilize this database of k-ratio intensities to train a neural net. However, the database is still incomplete with some areas of the periodic table still being calculated. But if someone is interested in pursuing this line of inquiry, I'd be pleased to participate.