#include <math.h>
#include <iostream.h>
#include <string>
Go to the source code of this file.
Functions | |
| double | U235flux (double) |
| double | RMPflux (double) |
| double | InverseBeta (double, double, int order=1) |
| void | PositronRange (double, double &, double &) |
| double | GammaComptonRange (std::string, double) |
| Returns the mean free path of photons through a given material. More... | |
| void | MyGdDecayModel (double, int &, double *) |
| void | NeutronPropagator (double R0, double R2, double &ke, double &a, double &pass, double *pn, double *rn, double &tn) |
The individual functions are implimented in their respective cpp files.
Author: Tim Bolton
Definition in file ReactorXC.hh.
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Returns the mean free path of photons through a given material. The function GammaComptonRange is implimented in GammaComptonRange.cpp. The first input is a string defining the material through which the photon propogates. The supported materials are "scintillator" and "oil" which are defined by ReactorConstants.hh. The second input is the energy of the photon entering the material. The function returns a double equal to the mean free path calculated with the Klein-Nishina cross section. Definition at line 13 of file GammaComptonRange.cpp.
00013 {
00014
00015 //cout << "gamma propogating through " << material << endl;
00016 //
00017 // Compute the mean free path for Compton scattering.
00018 //
00019 static ReactorConstants k;
00020 static double pi = k.pi;
00021 static double m = k.Melectron;
00022 static double alpha = 1/k.alphainv;
00023 static double Units = k.XcMeVtoCmsqrd;
00024 //
00025 // Overall cross section scale
00026 //
00027 static double Thomson = 8*pi*alpha*alpha/3/m/m*Units;
00028 double w = egamma/m;
00029 //
00030 // Klein-Nishina cross section
00031 //
00032 double XC = 3*Thomson/4*
00033 ((1+w)/w/w/w*(2*w*(1+w)/(1+2*w)-log(1+2*w))
00034 +log(1+2*w)/2/w-(1+3*w)/(1+2*w)/(1+2*w));
00035 //
00036 // Need electron density to get mfp. Get H and C contributions.
00037 //
00038 static double density = k.density;
00039 static double Na = k.Navogadro;
00040 static double A[2] = {k.A0,k.A1};
00041 static double Z[2] = {k.Z0,k.Z1};
00042 static double f[2];
00043 if(material == "scintillator"){
00044 f[0] = k.f0;
00045 f[1] = k.f1;
00046 }
00047 else if(material == "oil"){
00048 f[0] = k.f4;
00049 f[1] = k.f5;
00050 }
00051 else{
00052 cout << "GammaComptonRange: " << material
00053 << " is an unknown material! Assuming scintillator." << endl;
00054 f[0] = k.f0;
00055 f[1] = k.f1;
00056 }
00057 //for(int i=0;i<2;i++) cout << "f["<<i<<"] " << f[i] << endl;
00058 static double nel[2];
00059 static bool first = 1;
00060 for(int i=0;i<2;i++){
00061 nel[i]=Na*density*f[i]*Z[i]/A[i];
00062 first = 0;
00063 }
00064 //
00065 // Compute mean free path.
00066 //
00067 return 1/((nel[0]+nel[1])*XC);
00068 }
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1.2.14 written by Dimitri van Heesch,
© 1997-2002