Package PhotonAttenuation provides set of functions for modeling of photons (x-ray, gamma-ray, etc.), passing through different materials. The tools are based on attenuation and energy absorption coefficients of photons in various materials. The tables of absorption coefficients were copied from NIST and embedded in the MATLAB code.
Package consist of 4 functions:
PhotonAttenuation - the main function returning variuos physical quantaties for photons of various energies passing through different materials of different thickness
PhotonAttenuationQ - the helper function providing bare-bones access to NIST tables hardwired into the code. Simpler version of PhotonAttenuation function with much fiewer input and output options.
ParseChemicalFormula - converts many different styles of names used for elements, compounds and mixtures to uniform list of elements and their weight ratios.
PhysProps - provides physical properties (like ratio of atomic number to mass or density), needed by PhotonAttenuation function, for all elements and some selected compounds.
Tables are based on "X-Ray Attenuation and Absorption for Materials of Dosimetric Interest" (XAAMDI) database (NIST 5632 report): J. Hubbell and S.M. Seltzer, "Tables of X-Ray Mass Attenuation Coefficients and Mass Energy-Absorption Coefficients 1 keV to 20 MeV for Elements Z = 1 to 92 and 48 Additional Substances of Dosimetric Interest, "National Institute of Standards and Technology report NISTIR 5632 (1995). http://physics.nist.gov/PhysRefData/XrayMassCoef/cover.html
MAC values for elements 93 to 100 (Neptunium to Fermium) came from XCOM: Photon Cross Sections Database (NBSIR 87-3597): Those tables give photon's "total attenuation coefficients" for elements with atomic number (Z) smaller than 100. Photon energy range is from 0.001 MeV to 100 GeV. http://physics.nist.gov/PhysRefData/Xcom/Text/XCOM.html
Written by Jarek Tuszynski (SAIC), 2006
Inspired by John Schweppe Mathematica code available at http://library.wolfram.com/infocenter/MathSource/4267/
Jaroslaw Tuszynski (2021). PhotonAttenuation (https://www.mathworks.com/matlabcentral/fileexchange/12092-photonattenuation), MATLAB Central File Exchange. Retrieved .
The Tutorial.m worked for me the first time. Nice work.
Very useful code.
@Yi and Jarek,
The easy solution, which worked for me, is to simply initiate mu with the line
'mu = ;'
This can be inserted into line 160 just before the loop starts.
Why when I run the PhotonAttenuation_Tutorial.m directly, it will display the error information as:
Error: File: PhotonAttenuation.m Line: 192 Column: 3
"mu" previously appeared to be used as a function or command, conflicting with its use here as the name of a variable.
A possible cause of this error is that you forgot to initialize the
variable, or you have initialized it implicitly using load or eval.
Error in test_YZ (line 10)
mac = PhotonAttenuation(Z, E, 'mac');
Excellent work Jarek!
There is still one small problem with the plot of the attenuation curves - the edges should be "vertical" but in the plot they are not. This could be improved by adding the "NIST raw data" to the vector that is to be plotted before plotting (using vertcat and sortrows). Just a suggestion...
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