Author Topic: Matrix Corrections For Boron  (Read 10427 times)

Probeman

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    • John Donovan
Re: Matrix Corrections For Boron
« Reply #15 on: February 19, 2016, 02:31:10 PM »
What publications do the references "JD" and "ES" refer to?  When I press F1 with the X-ray database window open, I only see a list of the older publications.

Good questions.

The database file is XRAY.MDB and is in the ProgramData folder.  ES stands for Eric Steele. I think he tabulated the first order lines when he was at NIST. JD stands for me because I calculated the higher order reflections using this code:

Const HIGHERORDERFACTOREVEN! = 0.8
Const HIGHERORDERFACTORODD! = 0.5

' Even orders
If j% Mod 2 = 0 Then
txints1# = txints1# * HIGHERORDERFACTOREVEN!
If txints1# < 0.005 Then GoTo nextline
txints# = txints1#

' Odd orders
Else
txints2# = txints2# * HIGHERORDERFACTORODD!
If txints2# < 0.005 Then GoTo nextline
txints# = txints2#
End If

This is just a rough guess as obviously the intensities depend on lots of parameters.
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Brian Joy

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Re: Matrix Corrections For Boron
« Reply #16 on: February 20, 2016, 09:24:41 AM »
For a dose of reality, I’ve sumperimposed the peak determined by Bastin and Heijligers (1997) (solid curve in their plot) for B Ka in ZrB2 using the OVH pseudocrystal (Mo/B4C) with 2d ~ 147 angstroms.  (In plotting the peak, I used the wavelength scale at the top of the B&H plot in order to avoid the refraction correction necessary to convert from L-value to energy.)  Note the peak shift with crystal orientation in the plot from B&H (ZrB2 is in the hexagonal system).  Also note that B&H used peak integrals to determine k-ratios.

« Last Edit: April 14, 2020, 11:31:05 AM by John Donovan »
Brian Joy
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Probeman

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    • John Donovan
Re: Matrix Corrections For Boron
« Reply #17 on: February 21, 2016, 07:38:05 AM »
For a dose of reality, I’ve sumperimposed the peak determined by Bastin and Heijligers (1997) (solid curve in their plot) for B Ka in ZrB2 using the OVH pseudocrystal (Mo/B4C) with 2d ~ 147 angstroms.  (In plotting the peak, I used the wavelength scale at the top of the B&H plot in order to avoid the refraction correction necessary to convert from L-value to energy.)  Note the peak shift with crystal orientation in the plot from B&H (ZrB2 is in the hexagonal system).  Also note that B&H used peak integrals to determine k-ratios.



It appears to me that the empirical determinations (by Bastin and Pouchou) of these MACs are essentially "averaging" the mass absorption coefficients on both sides of the Zr absorption edge.   Which makes some sense since they are measurements using the integrated intensities. Though I suppose it depends on exactly what the boron ka emission line energy is (183 eV vs. 185 eV vs. ?)

It would be cool to plot the predicted *natural* line width of boron Ka on the same plot as above.

A *much* more nasty situation is boron Ka absorbed by Mg.  Here the MACs are in the range of 50,000 to 60,000! See the attached document below which is my first attempt to understand the MAC and APF effects in such a system.
john
« Last Edit: April 13, 2020, 10:36:55 PM by John Donovan »
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