[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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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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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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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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| 26 | // |
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| 27 | // $Id: G4RToEConvForGamma.cc,v 1.4 2006/06/29 19:30:24 gunter Exp $ |
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[1007] | 28 | // GEANT4 tag $Name: geant4-09-02 $ |
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[819] | 29 | // |
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| 30 | // |
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| 31 | // -------------------------------------------------------------- |
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| 32 | // GEANT 4 class implementation file/ History: |
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| 33 | // 5 Oct. 2002, H.Kuirashige : Structure created based on object model |
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| 34 | // -------------------------------------------------------------- |
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| 35 | |
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| 36 | #include "G4RToEConvForGamma.hh" |
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| 37 | #include "G4ParticleDefinition.hh" |
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| 38 | #include "G4ParticleTable.hh" |
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| 39 | #include "G4Material.hh" |
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| 40 | #include "G4PhysicsLogVector.hh" |
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| 41 | |
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| 42 | #include "G4ios.hh" |
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| 43 | |
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| 44 | G4RToEConvForGamma::G4RToEConvForGamma() : G4VRangeToEnergyConverter() |
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| 45 | { |
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| 46 | theParticle = G4ParticleTable::GetParticleTable()->FindParticle("gamma"); |
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| 47 | if (theParticle ==0) { |
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| 48 | #ifdef G4VERBOSE |
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| 49 | if (GetVerboseLevel()>0) { |
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| 50 | G4cout << " G4RToEConvForGamma::G4RToEConvForGamma() "; |
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| 51 | G4cout << " Gamma is not defined !!" << G4endl; |
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| 52 | } |
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| 53 | #endif |
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| 54 | } |
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| 55 | TotBin = 100; |
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| 56 | } |
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| 57 | |
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| 58 | G4RToEConvForGamma::~G4RToEConvForGamma() |
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| 59 | { |
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| 60 | } |
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| 61 | |
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| 62 | |
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| 63 | // *********************************************************************** |
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| 64 | // ******************* BuildAbsorptionLengthVector *********************** |
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| 65 | // *********************************************************************** |
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| 66 | void G4RToEConvForGamma::BuildAbsorptionLengthVector( |
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| 67 | const G4Material* aMaterial, |
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| 68 | G4double , |
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| 69 | G4double , |
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| 70 | G4RangeVector* absorptionLengthVector ) |
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| 71 | { |
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| 72 | // fill the absorption length vector for this material |
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| 73 | // absorption length is defined here as |
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| 74 | // |
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| 75 | // absorption length = 5./ macroscopic absorption cross section |
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| 76 | // |
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| 77 | const G4CrossSectionTable* aCrossSectionTable = (G4CrossSectionTable*)(theLossTable); |
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| 78 | const G4ElementVector* elementVector = aMaterial->GetElementVector(); |
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| 79 | const G4double* atomicNumDensityVector = aMaterial->GetAtomicNumDensityVector(); |
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| 80 | |
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| 81 | // fill absorption length vector |
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| 82 | G4int NumEl = aMaterial->GetNumberOfElements(); |
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| 83 | G4double absorptionLengthMax = 0.0; |
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| 84 | for (size_t ibin=0; ibin<size_t(TotBin); ibin++) { |
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| 85 | G4double lowEdgeEnergy = absorptionLengthVector->GetLowEdgeEnergy(ibin); |
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| 86 | |
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| 87 | G4double SIGMA = 0. ; |
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| 88 | |
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| 89 | for (size_t iel=0; iel<size_t(NumEl); iel++) { |
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| 90 | G4bool isOut; |
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| 91 | G4int IndEl = (*elementVector)[iel]->GetIndex(); |
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| 92 | SIGMA += atomicNumDensityVector[iel]* |
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| 93 | (*aCrossSectionTable)[IndEl]->GetValue(lowEdgeEnergy,isOut); |
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| 94 | } |
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| 95 | // absorption length=5./SIGMA |
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| 96 | absorptionLengthVector->PutValue(ibin, 5./SIGMA); |
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| 97 | if (absorptionLengthMax < 5./SIGMA ) absorptionLengthMax = 5./SIGMA; |
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| 98 | } |
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| 99 | } |
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| 100 | |
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| 101 | |
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| 102 | |
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| 103 | // *********************************************************************** |
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| 104 | // ********************** ComputeCrossSection **************************** |
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| 105 | // *********************************************************************** |
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| 106 | G4double G4RToEConvForGamma::ComputeCrossSection(G4double AtomicNumber, |
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| 107 | G4double KineticEnergy) const |
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| 108 | { |
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| 109 | // Compute the "absorption" cross section of the photon "absorption" |
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| 110 | // cross section means here the sum of the cross sections of the |
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| 111 | // pair production, Compton scattering and photoelectric processes |
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| 112 | static G4double Z; |
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| 113 | const G4double t1keV = 1.*keV; |
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| 114 | const G4double t200keV = 200.*keV; |
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| 115 | const G4double t100MeV = 100.*MeV; |
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| 116 | |
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| 117 | static G4double s200keV, s1keV; |
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| 118 | static G4double tmin, tlow; |
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| 119 | static G4double smin, slow; |
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| 120 | static G4double cmin, clow, chigh; |
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| 121 | // compute Z dependent quantities in the case of a new AtomicNumber |
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| 122 | if(std::abs(AtomicNumber-Z)>0.1) { |
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| 123 | Z = AtomicNumber; |
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| 124 | G4double Zsquare = Z*Z; |
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| 125 | G4double Zlog = std::log(Z); |
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| 126 | G4double Zlogsquare = Zlog*Zlog; |
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| 127 | |
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| 128 | s200keV = (0.2651-0.1501*Zlog+0.02283*Zlogsquare)*Zsquare; |
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| 129 | tmin = (0.552+218.5/Z+557.17/Zsquare)*MeV; |
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| 130 | smin = (0.01239+0.005585*Zlog-0.000923*Zlogsquare)*std::exp(1.5*Zlog); |
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| 131 | cmin=std::log(s200keV/smin)/(std::log(tmin/t200keV)*std::log(tmin/t200keV)); |
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| 132 | tlow = 0.2*std::exp(-7.355/std::sqrt(Z))*MeV; |
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| 133 | slow = s200keV*std::exp(0.042*Z*std::log(t200keV/tlow)*std::log(t200keV/tlow)); |
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| 134 | s1keV = 300.*Zsquare; |
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| 135 | clow =std::log(s1keV/slow)/std::log(tlow/t1keV); |
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| 136 | |
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| 137 | chigh=(7.55e-5-0.0542e-5*Z)*Zsquare*Z/std::log(t100MeV/tmin); |
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| 138 | } |
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| 139 | |
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| 140 | // calculate the cross section (using an approximate empirical formula) |
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| 141 | G4double s; |
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| 142 | if ( KineticEnergy<tlow ) { |
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| 143 | if(KineticEnergy<t1keV) s = slow*std::exp(clow*std::log(tlow/t1keV)); |
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| 144 | else s = slow*std::exp(clow*std::log(tlow/KineticEnergy)); |
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| 145 | |
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| 146 | } else if ( KineticEnergy<t200keV ) { |
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| 147 | s = s200keV |
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| 148 | * std::exp(0.042*Z*std::log(t200keV/KineticEnergy)*std::log(t200keV/KineticEnergy)); |
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| 149 | |
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| 150 | } else if( KineticEnergy<tmin ){ |
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| 151 | s = smin |
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| 152 | * std::exp(cmin*std::log(tmin/KineticEnergy)*std::log(tmin/KineticEnergy)); |
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| 153 | |
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| 154 | } else { |
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| 155 | s = smin + chigh*std::log(KineticEnergy/tmin); |
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| 156 | |
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| 157 | } |
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| 158 | return s * barn; |
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| 159 | } |
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| 160 | |
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