File:Photon Mean Free Path.png
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![File:Photon Mean Free Path.png](https://upload.wikimedia.org/wikipedia/commons/thumb/6/6f/Photon_Mean_Free_Path.png/769px-Photon_Mean_Free_Path.png)
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Summary
DescriptionPhoton Mean Free Path.png | Mean Free Path in cm, for photons in energy range from 1 keV to 20 MeV for Elements Z = 1 to 100. Based on data from [1]. The discontinuities are due to low density of gas elements. Six bands correspond to neighborhoods of six noble gases. Also shown are locations of photons absorption edges (and not Compton edges as mentioned in the comments from the Matlab code). |
Date | 10/04/2007 |
Source | Own work |
Author | Jarekt |
![](https://upload.wikimedia.org/wikipedia/commons/thumb/2/21/Matlab_Logo.png/25px-Matlab_Logo.png)
This diagram was created with MATLAB.
The image was generated using the following MATLAB code, with help of external library PhotonAtenuattion2:
%% Plot mean free path of photons in different media
% Plot as function of energy and atomic number of media/element
figure
Z = 1:99; % elements with Z in 1-100 range - number of columns
nr = 500; % number of rows to use in the plot
E = logspace(log10(0.001), log10(20), 500); % define energy grid
mfp = PhotonAttenuation(Z, E, 'mean free path');
colormap(jet(128)) % use hi-res color palette
imagesc(log10(mfp));
grid on;
axis xy; % put small numbers on y axis on the bottom
title('Mean free path of photons in different media (in cm)');
xlabel('Atomic number of elements');
ylabel('Energy in MeV');
% Add X-Axis
EPos = [6 16 26 35 47 55 65 74 82 94]; % define array to store label location
ELab = { '6-C','16-S','26-Fe','35-Br','47-Ag','55-Cs','65-Tb','74-W','82-Pb','94-Pu'}; %Define Energy labels for y-axis
set(gca,'XTick' ,EPos);
set(gca,'XTickLabel',ELab);
% Add Y-Axis
ELab = [0.001 0.003 0.01 0.03 0.1 0.3 1 3 10]; %Define Energy labels for y-axis
EPos = size(ELab); % define array to store label location
for i=1:length(ELab), [tmp EPos(i)]=min(abs(E-ELab(i))); end
set(gca,'YTick' ,EPos);
set(gca,'YTickLabel',ELab);
% add Colorbar
cbar_axes = colorbar;
set(cbar_axes,'YTick' , -5:5 ); % The image is a log10 of the MAC ...
set(cbar_axes,'YTickLabel',10.^(-5:5)); % ... so add proper labels
hold on
% Add Compton Edges to the plot
[tmp, CEdge] = PhotonAttenuationQ(Z, E);
ed = accumarray([CEdge(:,1),CEdge(:,2)],CEdge(:,3)); % get per element energies of 14 compton edges
ed = 500*(log(ed')-log(0.001))/(log(20)-log(0.001)); % convert energy to row numbers of the image
K=plot(ed(:,1) ,'m','LineWidth',3); %Plot K Compton edge
L=plot(ed(:, 2: 4),'r','LineWidth',2); %Plot 3 L Compton edges
M=plot(ed(:, 5: 9),'g','LineWidth',2); %Plot 5 M Compton edges
N=plot(ed(:,10:end),'y','LineWidth',2); %Plot first 5 N Compton edges
legend([K(1),L(1),M(1),N(1)], {'K','L','M','N'}, 'Location', 'NorthEast');
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Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue |
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 05:19, 15 August 2017 | ![]() | 1,097 × 855 (36 KB) | wikimediacommons>Mikhail Ryazanov | rm. excessive caps, crop top margin |
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