[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 | // $Id: G4MuBremsstrahlungModel.cc,v 1.24 2007/11/08 11:48:28 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-01-patch-02 $ |
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| 28 | // |
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| 29 | // ------------------------------------------------------------------- |
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| 30 | // |
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| 31 | // GEANT4 Class file |
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| 32 | // |
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| 33 | // |
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| 34 | // File name: G4MuBremsstrahlungModel |
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| 35 | // |
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| 36 | // Author: Vladimir Ivanchenko on base of Laszlo Urban code |
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| 37 | // |
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| 38 | // Creation date: 24.06.2002 |
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| 39 | // |
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| 40 | // Modifications: |
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| 41 | // |
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| 42 | // 04-12-02 Change G4DynamicParticle constructor in PostStepDoIt (V.Ivanchenko) |
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| 43 | // 23-12-02 Change interface in order to move to cut per region (V.Ivanchenko) |
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| 44 | // 24-01-03 Fix for compounds (V.Ivanchenko) |
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| 45 | // 27-01-03 Make models region aware (V.Ivanchenko) |
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| 46 | // 13-02-03 Add name (V.Ivanchenko) |
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| 47 | // 10-02-04 Add lowestKinEnergy (V.Ivanchenko) |
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| 48 | // 08-04-05 Major optimisation of internal interfaces (V.Ivantchenko) |
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| 49 | // 03-08-05 Angular correlations according to PRM (V.Ivantchenko) |
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| 50 | // 13-02-06 add ComputeCrossSectionPerAtom (mma) |
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| 51 | // 21-03-06 Fix problem of initialisation in case when cuts are not defined (VI) |
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| 52 | // 07-11-07 Improve sampling of final state (A.Bogdanov) |
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| 53 | // |
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| 54 | |
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| 55 | // |
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| 56 | // Class Description: |
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| 57 | // |
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| 58 | // |
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| 59 | // ------------------------------------------------------------------- |
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| 60 | // |
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| 61 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 62 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 63 | |
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| 64 | #include "G4MuBremsstrahlungModel.hh" |
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| 65 | #include "G4Gamma.hh" |
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| 66 | #include "G4MuonMinus.hh" |
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| 67 | #include "G4MuonPlus.hh" |
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| 68 | #include "Randomize.hh" |
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| 69 | #include "G4Material.hh" |
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| 70 | #include "G4Element.hh" |
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| 71 | #include "G4ElementVector.hh" |
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| 72 | #include "G4ProductionCutsTable.hh" |
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| 73 | #include "G4ParticleChangeForLoss.hh" |
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| 74 | |
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| 75 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 76 | |
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| 77 | // static members |
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| 78 | // |
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| 79 | G4double G4MuBremsstrahlungModel::zdat[]={1., 4., 13., 29., 92.}; |
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| 80 | G4double G4MuBremsstrahlungModel::adat[]={1.01, 9.01, 26.98, 63.55, 238.03}; |
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| 81 | G4double G4MuBremsstrahlungModel::tdat[]={1.e3, 1.e4, 1.e5, 1.e6, 1.e7, 1.e8, |
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| 82 | 1.e9, 1.e10}; |
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| 83 | |
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| 84 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 85 | |
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| 86 | using namespace std; |
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| 87 | |
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| 88 | G4MuBremsstrahlungModel::G4MuBremsstrahlungModel(const G4ParticleDefinition* p, |
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| 89 | const G4String& nam) |
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| 90 | : G4VEmModel(nam), |
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| 91 | particle(0), |
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| 92 | lowestKinEnergy(1.0*GeV), |
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| 93 | minThreshold(1.0*keV), |
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| 94 | nzdat(5), |
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| 95 | ntdat(8), |
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| 96 | NBIN(1000), |
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| 97 | cutFixed(0.98*keV), |
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| 98 | ignoreCut(false), |
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| 99 | samplingTablesAreFilled(false) |
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| 100 | { |
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| 101 | theGamma = G4Gamma::Gamma(); |
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| 102 | if(p) SetParticle(p); |
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| 103 | } |
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| 104 | |
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| 105 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 106 | |
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| 107 | G4MuBremsstrahlungModel::~G4MuBremsstrahlungModel() |
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| 108 | { |
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| 109 | size_t n = partialSumSigma.size(); |
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| 110 | if(n > 0) { |
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| 111 | for(size_t i=0; i<n; i++) { |
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| 112 | delete partialSumSigma[i]; |
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| 113 | } |
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| 114 | } |
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| 115 | } |
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| 116 | |
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| 117 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 118 | |
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| 119 | G4double G4MuBremsstrahlungModel::MinEnergyCut(const G4ParticleDefinition*, |
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| 120 | const G4MaterialCutsCouple*) |
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| 121 | { |
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| 122 | return minThreshold; |
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| 123 | } |
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| 124 | |
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| 125 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 126 | |
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| 127 | void G4MuBremsstrahlungModel::SetParticle(const G4ParticleDefinition* p) |
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| 128 | { |
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| 129 | if(!particle) { |
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| 130 | particle = p; |
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| 131 | mass = particle->GetPDGMass(); |
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| 132 | } |
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| 133 | } |
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| 134 | |
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| 135 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 136 | |
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| 137 | void G4MuBremsstrahlungModel::Initialise(const G4ParticleDefinition* p, |
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| 138 | const G4DataVector& cuts) |
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| 139 | { |
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| 140 | if(p) SetParticle(p); |
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| 141 | |
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| 142 | highKinEnergy = HighEnergyLimit(); |
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| 143 | |
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| 144 | G4double fixedEnergy = 0.5*highKinEnergy; |
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| 145 | |
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| 146 | const G4ProductionCutsTable* theCoupleTable= |
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| 147 | G4ProductionCutsTable::GetProductionCutsTable(); |
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| 148 | if(theCoupleTable) { |
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| 149 | G4int numOfCouples = theCoupleTable->GetTableSize(); |
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| 150 | |
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| 151 | G4int nn = partialSumSigma.size(); |
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| 152 | G4int nc = cuts.size(); |
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| 153 | if(nn > 0) { |
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| 154 | for (G4int ii=0; ii<nn; ii++){ |
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| 155 | G4DataVector* a=partialSumSigma[ii]; |
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| 156 | if ( a ) delete a; |
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| 157 | } |
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| 158 | partialSumSigma.clear(); |
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| 159 | } |
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| 160 | if (numOfCouples>0) { |
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| 161 | for (G4int i=0; i<numOfCouples; i++) { |
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| 162 | G4double cute = DBL_MAX; |
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| 163 | if(i < nc) cute = cuts[i]; |
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| 164 | if(cute < cutFixed || ignoreCut) cute = cutFixed; |
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| 165 | const G4MaterialCutsCouple* couple = |
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| 166 | theCoupleTable->GetMaterialCutsCouple(i); |
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| 167 | const G4Material* material = couple->GetMaterial(); |
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| 168 | G4DataVector* dv = ComputePartialSumSigma(material,fixedEnergy,cute); |
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| 169 | partialSumSigma.push_back(dv); |
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| 170 | } |
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| 171 | } |
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| 172 | } |
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| 173 | if(!samplingTablesAreFilled) MakeSamplingTables(); |
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| 174 | if(pParticleChange) |
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| 175 | fParticleChange = |
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| 176 | reinterpret_cast<G4ParticleChangeForLoss*>(pParticleChange); |
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| 177 | else |
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| 178 | fParticleChange = new G4ParticleChangeForLoss(); |
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| 179 | } |
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| 180 | |
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| 181 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 182 | |
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| 183 | G4double G4MuBremsstrahlungModel::ComputeDEDXPerVolume( |
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| 184 | const G4Material* material, |
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| 185 | const G4ParticleDefinition*, |
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| 186 | G4double kineticEnergy, |
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| 187 | G4double cutEnergy) |
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| 188 | { |
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| 189 | G4double dedx = 0.0; |
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| 190 | if (kineticEnergy <= lowestKinEnergy || ignoreCut) return dedx; |
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| 191 | |
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| 192 | G4double tmax = kineticEnergy; |
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| 193 | G4double cut = min(cutEnergy,tmax); |
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| 194 | if(cut < cutFixed) cut = cutFixed; |
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| 195 | |
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| 196 | const G4ElementVector* theElementVector = material->GetElementVector(); |
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| 197 | const G4double* theAtomicNumDensityVector = |
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| 198 | material->GetAtomicNumDensityVector(); |
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| 199 | |
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| 200 | // loop for elements in the material |
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| 201 | for (size_t i=0; i<material->GetNumberOfElements(); i++) { |
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| 202 | |
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| 203 | G4double Z = (*theElementVector)[i]->GetZ(); |
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| 204 | G4double A = (*theElementVector)[i]->GetA()/(g/mole) ; |
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| 205 | |
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| 206 | G4double loss = ComputMuBremLoss(Z, A, kineticEnergy, cut); |
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| 207 | |
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| 208 | dedx += loss*theAtomicNumDensityVector[i]; |
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| 209 | } |
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| 210 | if(dedx < 0.) dedx = 0.; |
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| 211 | return dedx; |
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| 212 | } |
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| 213 | |
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| 214 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 215 | |
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| 216 | G4double G4MuBremsstrahlungModel::ComputMuBremLoss(G4double Z, G4double A, |
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| 217 | G4double tkin, G4double cut) |
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| 218 | { |
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| 219 | G4double totalEnergy = mass + tkin; |
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| 220 | G4double ak1 = 0.05; |
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| 221 | G4int k2=5; |
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| 222 | G4double xgi[]={0.03377,0.16940,0.38069,0.61931,0.83060,0.96623}; |
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| 223 | G4double wgi[]={0.08566,0.18038,0.23396,0.23396,0.18038,0.08566}; |
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| 224 | G4double loss = 0.; |
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| 225 | |
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| 226 | G4double vcut = cut/totalEnergy; |
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| 227 | G4double vmax = tkin/totalEnergy; |
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| 228 | |
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| 229 | G4double aaa = 0.; |
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| 230 | G4double bbb = vcut; |
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| 231 | if(vcut>vmax) bbb=vmax ; |
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| 232 | G4int kkk = (G4int)((bbb-aaa)/ak1)+k2 ; |
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| 233 | G4double hhh=(bbb-aaa)/float(kkk) ; |
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| 234 | |
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| 235 | G4double aa = aaa; |
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| 236 | for(G4int l=0; l<kkk; l++) |
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| 237 | { |
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| 238 | for(G4int i=0; i<6; i++) |
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| 239 | { |
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| 240 | G4double ep = (aa + xgi[i]*hhh)*totalEnergy; |
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| 241 | loss += ep*wgi[i]*ComputeDMicroscopicCrossSection(tkin, Z, A, ep); |
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| 242 | } |
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| 243 | aa += hhh; |
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| 244 | } |
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| 245 | |
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| 246 | loss *=hhh*totalEnergy ; |
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| 247 | |
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| 248 | return loss; |
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| 249 | } |
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| 250 | |
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| 251 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 252 | |
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| 253 | G4double G4MuBremsstrahlungModel::ComputeMicroscopicCrossSection( |
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| 254 | G4double tkin, |
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| 255 | G4double Z, |
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| 256 | G4double A, |
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| 257 | G4double cut) |
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| 258 | { |
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| 259 | G4double totalEnergy = tkin + mass; |
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| 260 | G4double ak1 = 2.3; |
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| 261 | G4int k2 = 4; |
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| 262 | G4double xgi[]={0.03377,0.16940,0.38069,0.61931,0.83060,0.96623}; |
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| 263 | G4double wgi[]={0.08566,0.18038,0.23396,0.23396,0.18038,0.08566}; |
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| 264 | G4double cross = 0.; |
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| 265 | |
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| 266 | if(cut >= tkin) return cross; |
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| 267 | |
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| 268 | G4double vcut = cut/totalEnergy; |
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| 269 | G4double vmax = tkin/totalEnergy; |
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| 270 | |
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| 271 | G4double aaa = log(vcut); |
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| 272 | G4double bbb = log(vmax); |
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| 273 | G4int kkk = (G4int)((bbb-aaa)/ak1)+k2 ; |
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| 274 | G4double hhh = (bbb-aaa)/float(kkk); |
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| 275 | |
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| 276 | G4double aa = aaa; |
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| 277 | |
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| 278 | for(G4int l=0; l<kkk; l++) |
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| 279 | { |
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| 280 | for(G4int i=0; i<6; i++) |
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| 281 | { |
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| 282 | G4double ep = exp(aa + xgi[i]*hhh)*totalEnergy; |
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| 283 | cross += ep*wgi[i]*ComputeDMicroscopicCrossSection(tkin, Z, A, ep); |
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| 284 | } |
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| 285 | aa += hhh; |
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| 286 | } |
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| 287 | |
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| 288 | cross *=hhh; |
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| 289 | |
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| 290 | return cross; |
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| 291 | } |
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| 292 | |
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| 293 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 294 | |
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| 295 | G4double G4MuBremsstrahlungModel::ComputeDMicroscopicCrossSection( |
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| 296 | G4double tkin, |
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| 297 | G4double Z, |
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| 298 | G4double A, |
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| 299 | G4double gammaEnergy) |
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| 300 | // differential cross section |
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| 301 | { |
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| 302 | static const G4double sqrte=sqrt(exp(1.)) ; |
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| 303 | static const G4double bh=202.4,bh1=446.,btf=183.,btf1=1429. ; |
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| 304 | static const G4double rmass=mass/electron_mass_c2 ; |
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| 305 | static const G4double cc=classic_electr_radius/rmass ; |
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| 306 | static const G4double coeff= 16.*fine_structure_const*cc*cc/3. ; |
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| 307 | |
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| 308 | G4double dxsection = 0.; |
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| 309 | |
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| 310 | if( gammaEnergy > tkin) return dxsection ; |
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| 311 | |
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| 312 | G4double E = tkin + mass ; |
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| 313 | G4double v = gammaEnergy/E ; |
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| 314 | G4double delta = 0.5*mass*mass*v/(E-gammaEnergy) ; |
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| 315 | G4double rab0=delta*sqrte ; |
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| 316 | |
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| 317 | G4double z13 = exp(-log(Z)/3.) ; |
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| 318 | G4double dn = 1.54*exp(0.27*log(A)) ; |
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| 319 | |
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| 320 | G4double b,b1,dnstar ; |
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| 321 | |
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| 322 | if(Z<1.5) |
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| 323 | { |
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| 324 | b=bh; |
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| 325 | b1=bh1; |
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| 326 | dnstar=dn ; |
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| 327 | } |
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| 328 | else |
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| 329 | { |
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| 330 | b=btf; |
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| 331 | b1=btf1; |
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| 332 | dnstar = exp((1.-1./Z)*log(dn)) ; |
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| 333 | } |
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| 334 | |
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| 335 | // nucleus contribution logarithm |
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| 336 | G4double rab1=b*z13; |
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| 337 | G4double fn=log(rab1/(dnstar*(electron_mass_c2+rab0*rab1))* |
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| 338 | (mass+delta*(dnstar*sqrte-2.))) ; |
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| 339 | if(fn <0.) fn = 0. ; |
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| 340 | // electron contribution logarithm |
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| 341 | G4double epmax1=E/(1.+0.5*mass*rmass/E) ; |
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| 342 | G4double fe=0.; |
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| 343 | if(gammaEnergy<epmax1) |
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| 344 | { |
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| 345 | G4double rab2=b1*z13*z13 ; |
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| 346 | fe=log(rab2*mass/((1.+delta*rmass/(electron_mass_c2*sqrte))* |
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| 347 | (electron_mass_c2+rab0*rab2))) ; |
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| 348 | if(fe<0.) fe=0. ; |
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| 349 | } |
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| 350 | |
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| 351 | dxsection = coeff*(1.-v*(1. - 0.75*v))*Z*(fn*Z + fe)/gammaEnergy; |
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| 352 | |
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| 353 | return dxsection; |
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| 354 | } |
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| 355 | |
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| 356 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 357 | |
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| 358 | G4double G4MuBremsstrahlungModel::ComputeCrossSectionPerAtom( |
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| 359 | const G4ParticleDefinition*, |
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| 360 | G4double kineticEnergy, |
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| 361 | G4double Z, G4double A, |
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| 362 | G4double cutEnergy, |
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| 363 | G4double) |
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| 364 | { |
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| 365 | G4double cut = min(cutEnergy, kineticEnergy); |
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| 366 | if(cut < cutFixed || ignoreCut) cut = cutFixed; |
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| 367 | G4double cross = |
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| 368 | ComputeMicroscopicCrossSection (kineticEnergy, Z, A/(g/mole), cut); |
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| 369 | return cross; |
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| 370 | } |
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| 371 | |
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| 372 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 373 | |
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| 374 | G4double G4MuBremsstrahlungModel::CrossSectionPerVolume( |
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| 375 | const G4Material* material, |
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| 376 | const G4ParticleDefinition*, |
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| 377 | G4double kineticEnergy, |
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| 378 | G4double cutEnergy, |
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| 379 | G4double maxEnergy) |
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| 380 | { |
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| 381 | G4double cross = 0.0; |
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| 382 | if (cutEnergy >= maxEnergy || kineticEnergy <= lowestKinEnergy) return cross; |
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| 383 | |
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| 384 | G4double tmax = min(maxEnergy, kineticEnergy); |
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| 385 | G4double cut = min(cutEnergy, tmax); |
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| 386 | if(cut < cutFixed || ignoreCut) cut = cutFixed; |
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| 387 | |
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| 388 | const G4ElementVector* theElementVector = material->GetElementVector(); |
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| 389 | const G4double* theAtomNumDensityVector = |
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| 390 | material->GetAtomicNumDensityVector(); |
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| 391 | |
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| 392 | for (size_t i=0; i<material->GetNumberOfElements(); i++) { |
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| 393 | |
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| 394 | G4double Z = (*theElementVector)[i]->GetZ(); |
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| 395 | G4double A = (*theElementVector)[i]->GetA()/(g/mole); |
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| 396 | |
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| 397 | G4double cr = ComputeMicroscopicCrossSection(kineticEnergy, Z, A, cut); |
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| 398 | |
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| 399 | if(tmax < kineticEnergy) { |
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| 400 | cr -= ComputeMicroscopicCrossSection(kineticEnergy, Z, A, tmax); |
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| 401 | } |
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| 402 | cross += theAtomNumDensityVector[i] * cr; |
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| 403 | } |
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| 404 | |
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| 405 | return cross; |
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| 406 | } |
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| 407 | |
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| 408 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 409 | |
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| 410 | G4DataVector* G4MuBremsstrahlungModel::ComputePartialSumSigma( |
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| 411 | const G4Material* material, |
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| 412 | G4double kineticEnergy, |
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| 413 | G4double cut) |
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| 414 | |
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| 415 | // Build the table of cross section per element. The table is built for MATERIAL |
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| 416 | // This table is used by DoIt to select randomly an element in the material. |
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| 417 | { |
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| 418 | G4int nElements = material->GetNumberOfElements(); |
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| 419 | const G4ElementVector* theElementVector = material->GetElementVector(); |
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| 420 | const G4double* theAtomNumDensityVector = |
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| 421 | material->GetAtomicNumDensityVector(); |
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| 422 | |
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| 423 | G4DataVector* dv = new G4DataVector(); |
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| 424 | |
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| 425 | G4double cross = 0.0; |
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| 426 | |
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| 427 | for (G4int i=0; i<nElements; i++ ) { |
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| 428 | |
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| 429 | G4double Z = (*theElementVector)[i]->GetZ(); |
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| 430 | G4double A = (*theElementVector)[i]->GetA()/(g/mole) ; |
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| 431 | cross += theAtomNumDensityVector[i] |
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| 432 | * ComputeMicroscopicCrossSection(kineticEnergy, Z, A, cut); |
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| 433 | dv->push_back(cross); |
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| 434 | } |
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| 435 | return dv; |
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| 436 | } |
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| 437 | |
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| 438 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 439 | |
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| 440 | void G4MuBremsstrahlungModel::MakeSamplingTables() |
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| 441 | { |
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| 442 | |
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| 443 | G4double AtomicNumber,AtomicWeight,KineticEnergy, |
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| 444 | TotalEnergy,Maxep; |
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| 445 | |
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| 446 | for (G4int iz=0; iz<nzdat; iz++) |
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| 447 | { |
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| 448 | AtomicNumber = zdat[iz]; |
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| 449 | AtomicWeight = adat[iz]*g/mole ; |
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| 450 | |
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| 451 | for (G4int it=0; it<ntdat; it++) |
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| 452 | { |
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| 453 | KineticEnergy = tdat[it]; |
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| 454 | TotalEnergy = KineticEnergy + mass; |
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| 455 | Maxep = KineticEnergy ; |
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| 456 | |
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| 457 | G4double CrossSection = 0.0 ; |
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| 458 | |
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| 459 | // calculate the differential cross section |
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| 460 | // numerical integration in |
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| 461 | // log ............... |
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| 462 | G4double c = log(Maxep/cutFixed) ; |
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| 463 | G4double ymin = -5. ; |
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| 464 | G4double ymax = 0. ; |
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| 465 | G4double dy = (ymax-ymin)/NBIN ; |
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| 466 | |
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| 467 | G4double y = ymin - 0.5*dy ; |
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| 468 | G4double yy = ymin - dy ; |
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| 469 | G4double x = exp(y); |
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| 470 | G4double fac = exp(dy); |
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| 471 | G4double dx = exp(yy)*(fac - 1.0); |
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| 472 | |
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| 473 | for (G4int i=0 ; i<NBIN; i++) |
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| 474 | { |
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| 475 | y += dy ; |
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| 476 | x *= fac; |
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| 477 | dx*= fac; |
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| 478 | G4double ep = cutFixed*exp(c*x) ; |
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| 479 | |
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| 480 | CrossSection += ep*dx*ComputeDMicroscopicCrossSection( |
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| 481 | KineticEnergy,AtomicNumber, |
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| 482 | AtomicWeight,ep) ; |
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| 483 | ya[i]=y ; |
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| 484 | proba[iz][it][i] = CrossSection ; |
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| 485 | |
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| 486 | } |
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| 487 | |
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| 488 | proba[iz][it][NBIN] = CrossSection ; |
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| 489 | ya[NBIN] = 0. ; // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! |
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| 490 | |
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| 491 | if(CrossSection > 0.) |
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| 492 | { |
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| 493 | for(G4int ib=0; ib<=NBIN; ib++) |
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| 494 | { |
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| 495 | proba[iz][it][ib] /= CrossSection ; |
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| 496 | } |
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| 497 | } |
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| 498 | } |
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| 499 | } |
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| 500 | samplingTablesAreFilled = true; |
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| 501 | } |
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| 502 | |
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| 503 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 504 | |
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| 505 | void G4MuBremsstrahlungModel::SampleSecondaries(std::vector<G4DynamicParticle*>* vdp, |
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| 506 | const G4MaterialCutsCouple* couple, |
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| 507 | const G4DynamicParticle* dp, |
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| 508 | G4double minEnergy, |
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| 509 | G4double maxEnergy) |
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| 510 | { |
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| 511 | G4double kineticEnergy = dp->GetKineticEnergy(); |
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| 512 | // check against insufficient energy |
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| 513 | G4double tmax = min(kineticEnergy, maxEnergy); |
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| 514 | G4double tmin = min(kineticEnergy, minEnergy); |
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| 515 | if(tmin < cutFixed || ignoreCut) tmin = cutFixed; |
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| 516 | if(tmin >= tmax) return; |
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| 517 | |
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| 518 | // ===== the begining of a new code ====== |
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| 519 | // ===== sampling of energy transfer ====== |
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| 520 | |
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| 521 | G4ParticleMomentum partDirection = dp->GetMomentumDirection(); |
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| 522 | |
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| 523 | // select randomly one element constituing the material |
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| 524 | const G4Element* anElement = SelectRandomAtom(couple); |
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| 525 | |
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| 526 | G4double totalEnergy = kineticEnergy + mass; |
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| 527 | G4double totalMomentum = sqrt(kineticEnergy*(kineticEnergy + 2.0*mass)); |
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| 528 | |
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| 529 | G4double AtomicNumber = anElement->GetZ(); |
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| 530 | G4double AtomicWeight = anElement->GetA()/(g/mole); |
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| 531 | |
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| 532 | G4double func1 = tmin*ComputeDMicroscopicCrossSection( |
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| 533 | kineticEnergy,AtomicNumber, |
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| 534 | AtomicWeight,tmin); |
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| 535 | |
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| 536 | G4double lnepksi, epksi; |
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| 537 | G4double func2; |
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| 538 | G4double ksi2; |
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| 539 | |
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| 540 | do { |
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| 541 | lnepksi = log(tmin) + G4UniformRand()*log(kineticEnergy/tmin); |
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| 542 | epksi = exp(lnepksi); |
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| 543 | func2 = epksi*ComputeDMicroscopicCrossSection( |
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| 544 | kineticEnergy,AtomicNumber, |
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| 545 | AtomicWeight,epksi); |
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| 546 | ksi2 = G4UniformRand(); |
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| 547 | |
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| 548 | } while(func2/func1 < ksi2); |
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| 549 | |
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| 550 | // ===== the end of a new code ===== |
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| 551 | |
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| 552 | // create G4DynamicParticle object for the Gamma |
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| 553 | G4double gEnergy = epksi; |
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| 554 | |
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| 555 | // sample angle |
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| 556 | G4double gam = totalEnergy/mass; |
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| 557 | G4double rmax = gam*min(1.0, totalEnergy/gEnergy - 1.0); |
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| 558 | rmax *= rmax; |
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| 559 | G4double x = G4UniformRand()*rmax/(1.0 + rmax); |
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| 560 | |
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| 561 | G4double theta = sqrt(x/(1.0 - x))/gam; |
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| 562 | G4double sint = sin(theta); |
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| 563 | G4double phi = twopi * G4UniformRand() ; |
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| 564 | G4double dirx = sint*cos(phi), diry = sint*sin(phi), dirz = cos(theta) ; |
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| 565 | |
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| 566 | G4ThreeVector gDirection(dirx, diry, dirz); |
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| 567 | gDirection.rotateUz(partDirection); |
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| 568 | |
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| 569 | partDirection *= totalMomentum; |
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| 570 | partDirection -= gEnergy*gDirection; |
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| 571 | partDirection = partDirection.unit(); |
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| 572 | |
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| 573 | // primary change |
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| 574 | kineticEnergy -= gEnergy; |
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| 575 | fParticleChange->SetProposedKineticEnergy(kineticEnergy); |
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| 576 | fParticleChange->SetProposedMomentumDirection(partDirection); |
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| 577 | |
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| 578 | // save secondary |
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| 579 | G4DynamicParticle* aGamma = new G4DynamicParticle(theGamma,gDirection,gEnergy); |
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| 580 | vdp->push_back(aGamma); |
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| 581 | } |
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| 582 | |
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| 583 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 584 | |
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| 585 | const G4Element* G4MuBremsstrahlungModel::SelectRandomAtom( |
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| 586 | const G4MaterialCutsCouple* couple) const |
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| 587 | { |
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| 588 | // select randomly 1 element within the material |
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| 589 | |
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| 590 | const G4Material* material = couple->GetMaterial(); |
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| 591 | G4int nElements = material->GetNumberOfElements(); |
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| 592 | const G4ElementVector* theElementVector = material->GetElementVector(); |
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| 593 | if(1 == nElements) return (*theElementVector)[0]; |
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| 594 | else if(1 > nElements) return 0; |
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| 595 | |
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| 596 | G4DataVector* dv = partialSumSigma[couple->GetIndex()]; |
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| 597 | G4double rval = G4UniformRand()*((*dv)[nElements-1]); |
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| 598 | for (G4int i=0; i<nElements; i++) { |
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| 599 | if (rval <= (*dv)[i]) return (*theElementVector)[i]; |
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| 600 | } |
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| 601 | return (*theElementVector)[nElements-1]; |
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| 602 | } |
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| 603 | |
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| 604 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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