[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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[961] | 26 | // $Id: G4CrossSectionExcitationEmfietzoglouPartial.cc,v 1.3 2008/07/14 20:47:34 sincerti Exp $ |
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[991] | 27 | // GEANT4 tag $Name: geant4-09-02 $ |
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[819] | 28 | |
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| 29 | #include "G4CrossSectionExcitationEmfietzoglouPartial.hh" |
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| 30 | |
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[961] | 31 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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[819] | 32 | |
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| 33 | G4CrossSectionExcitationEmfietzoglouPartial::G4CrossSectionExcitationEmfietzoglouPartial() |
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| 34 | { |
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| 35 | nLevels = waterExcitation.NumberOfLevels(); |
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| 36 | } |
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| 37 | |
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[961] | 38 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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[819] | 39 | |
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| 40 | G4CrossSectionExcitationEmfietzoglouPartial::~G4CrossSectionExcitationEmfietzoglouPartial() |
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[961] | 41 | {} |
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[819] | 42 | |
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[961] | 43 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 44 | |
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[819] | 45 | G4double G4CrossSectionExcitationEmfietzoglouPartial::CrossSection(G4double t, G4int level) |
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| 46 | { |
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| 47 | // Aj T |
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| 48 | // Sigma(T) = ------------- (Bj / T) ln(Cj ---) [1 - Bj / T]^Pj |
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| 49 | // 2 pi alpha0 R |
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| 50 | // |
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| 51 | // Sigma is the macroscopic cross section = N sigma, where N = number of target particles per unit volume |
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| 52 | // and sigma is the microscopic cross section |
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| 53 | // T is the incoming electron kinetic energy |
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| 54 | // alpha0 is the Bohr Radius (Bohr_radius) |
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| 55 | // Aj, Bj, Cj & Pj are parameters that can be found in Emfietzoglou's papers |
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| 56 | // |
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| 57 | // From Phys. Med. Biol. 48 (2003) 2355-2371, D.Emfietzoglou, |
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| 58 | // Monte Carlo Simulation of the energy loss of low energy electrons in liquid Water |
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[961] | 59 | // |
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[819] | 60 | // Scaling for macroscopic cross section: number of water moleculs per unit volume |
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[961] | 61 | // const G4double sigma0 = (10. / 3.343e22) * cm2; |
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| 62 | |
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[819] | 63 | const G4double density = 3.34192e+19 * mm3; |
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| 64 | |
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| 65 | const G4double aj[]={0.0205, 0.0209, 0.0130, 0.0026, 0.0025}; |
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| 66 | const G4double cj[]={4.9801, 3.3850, 2.8095, 1.9242, 3.4624}; |
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| 67 | const G4double pj[]={0.4757, 0.3483, 0.4443, 0.3429, 0.4379}; |
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| 68 | const G4double r = 13.6 * eV; |
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| 69 | |
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| 70 | G4double sigma = 0.; |
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| 71 | |
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| 72 | G4double exc = waterExcitation.ExcitationEnergy(level); |
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[961] | 73 | |
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[819] | 74 | if (t >= exc) |
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| 75 | { |
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| 76 | G4double excitationSigma = ( aj[level] / (2.*pi*Bohr_radius)) |
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| 77 | * (exc / t) |
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| 78 | * std::log(cj[level]*(t/r)) |
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| 79 | * std::pow((1.- (exc/t)), pj[level]); |
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| 80 | sigma = excitationSigma / density; |
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| 81 | } |
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| 82 | return sigma; |
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| 83 | } |
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| 84 | |
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[961] | 85 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 86 | |
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[819] | 87 | G4int G4CrossSectionExcitationEmfietzoglouPartial::RandomSelect(G4double k) |
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| 88 | { |
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| 89 | G4int i = nLevels; |
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| 90 | G4double value = 0.; |
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| 91 | std::deque<double> values; |
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| 92 | |
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[961] | 93 | // ---- MGP ---- The following algorithm is wrong: it works if the cross section |
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[819] | 94 | // is a monotone increasing function. |
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| 95 | // The algorithm should be corrected by building the cumulative function |
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| 96 | // of the cross section and comparing a random number in the range 0-1 against |
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| 97 | // the cumulative value at each bin |
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| 98 | |
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| 99 | while (i > 0) |
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[961] | 100 | { |
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| 101 | i--; |
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| 102 | G4double partial = CrossSection(k,i); |
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| 103 | values.push_front(partial); |
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| 104 | value += partial; |
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| 105 | } |
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[819] | 106 | |
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[961] | 107 | value *= G4UniformRand(); |
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[819] | 108 | |
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[961] | 109 | i = nLevels; |
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[819] | 110 | |
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[961] | 111 | while (i > 0) |
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| 112 | { |
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| 113 | i--; |
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| 114 | if (values[i] > value) return i; |
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| 115 | value -= values[i]; |
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| 116 | } |
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[819] | 117 | |
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[961] | 118 | return 0; |
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[819] | 119 | } |
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| 120 | |
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[961] | 121 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 122 | |
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[819] | 123 | G4double G4CrossSectionExcitationEmfietzoglouPartial::Sum(G4double k) |
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| 124 | { |
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| 125 | G4double totalCrossSection = 0.; |
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| 126 | |
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| 127 | for (G4int i=0; i<nLevels; i++) |
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[961] | 128 | { |
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| 129 | totalCrossSection += CrossSection(k,i); |
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| 130 | } |
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[819] | 131 | return totalCrossSection; |
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| 132 | } |
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