[968] | 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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[1055] | 26 | // $Id: G4eeToPGammaModel.cc,v 1.2 2009/02/20 16:38:33 vnivanch Exp $ |
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[1228] | 27 | // GEANT4 tag $Name: geant4-09-03 $ |
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[968] | 28 | // |
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| 29 | // ------------------------------------------------------------------- |
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| 30 | // |
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| 31 | // GEANT4 Class header file |
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| 32 | // |
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| 33 | // |
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| 34 | // File name: G4eeToPGammaModel |
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| 35 | // |
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| 36 | // Author: Vladimir Ivanchenko |
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| 37 | // |
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| 38 | // Creation date: 25.10.2003 |
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| 39 | // |
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| 40 | // Modifications: |
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| 41 | // |
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| 42 | // |
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| 43 | // ------------------------------------------------------------------- |
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| 44 | // |
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| 45 | |
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| 46 | |
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| 47 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 48 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 49 | |
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| 50 | #include "G4eeToPGammaModel.hh" |
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| 51 | #include "Randomize.hh" |
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| 52 | #include "G4PionZero.hh" |
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| 53 | #include "G4Eta.hh" |
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| 54 | #include "G4Gamma.hh" |
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| 55 | #include "G4DynamicParticle.hh" |
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| 56 | #include "G4PhysicsVector.hh" |
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| 57 | #include "G4PhysicsLinearVector.hh" |
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| 58 | #include "G4eeCrossSections.hh" |
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| 59 | |
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| 60 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 61 | |
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| 62 | using namespace std; |
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| 63 | |
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| 64 | G4eeToPGammaModel::G4eeToPGammaModel(G4eeCrossSections* cr, const G4String& npart): |
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| 65 | cross(cr) |
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| 66 | { |
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| 67 | pi0 = G4PionZero::PionZero(); |
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| 68 | if(npart == "pi0") { |
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| 69 | massR = 782.62*MeV; |
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| 70 | particle = pi0; |
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| 71 | } else { |
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| 72 | massR = 1019.46*MeV; |
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| 73 | particle = G4Eta::Eta(); |
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| 74 | } |
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| 75 | massP = particle->GetPDGMass(); |
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| 76 | } |
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| 77 | |
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| 78 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 79 | |
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| 80 | G4eeToPGammaModel::~G4eeToPGammaModel() |
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| 81 | {} |
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| 82 | |
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| 83 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 84 | |
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[1055] | 85 | G4double G4eeToPGammaModel::ThresholdEnergy() const |
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| 86 | { |
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| 87 | return LowEnergy(); |
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| 88 | } |
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| 89 | |
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| 90 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 91 | |
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| 92 | G4double G4eeToPGammaModel::PeakEnergy() const |
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| 93 | { |
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| 94 | return massR; |
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| 95 | } |
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| 96 | |
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| 97 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 98 | |
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| 99 | G4double G4eeToPGammaModel::ComputeCrossSection(G4double e) const |
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| 100 | { |
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| 101 | G4double ee = std::min(HighEnergy(),e); |
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| 102 | G4double xs; |
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| 103 | if(particle == pi0) xs = cross->CrossSectionPi0G(ee); |
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| 104 | else xs = cross->CrossSectionEtaG(ee); |
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| 105 | return xs; |
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| 106 | } |
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| 107 | |
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| 108 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 109 | |
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[968] | 110 | G4PhysicsVector* G4eeToPGammaModel::PhysicsVector(G4double emin, |
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| 111 | G4double emax) const |
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| 112 | { |
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| 113 | G4double tmin = std::max(emin, ThresholdEnergy()); |
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| 114 | G4double tmax = std::max(tmin, emax); |
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| 115 | G4int nbins = (G4int)((tmax - tmin)/(5.*MeV)); |
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| 116 | G4PhysicsVector* v = new G4PhysicsLinearVector(emin,emax,nbins); |
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| 117 | v->SetSpline(true); |
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| 118 | return v; |
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| 119 | } |
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| 120 | |
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| 121 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 122 | |
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| 123 | void G4eeToPGammaModel::SampleSecondaries(std::vector<G4DynamicParticle*>* newp, |
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| 124 | G4double e, const G4ThreeVector& direction) |
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| 125 | { |
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| 126 | G4double egam = 0.5*e*(1.0 - massP*massP/(massR*massR)); |
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| 127 | G4double tkin = e - egam - massP; |
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| 128 | if(tkin < 0.0) tkin = 0.0; |
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| 129 | G4double cost; |
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| 130 | do { |
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| 131 | cost = 2.0*G4UniformRand() - 1.0; |
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| 132 | } while( 2.0*G4UniformRand() > 1.0 + cost*cost ); |
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| 133 | |
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| 134 | G4double sint = sqrt(1.0 - cost*cost); |
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| 135 | G4double phi = twopi * G4UniformRand(); |
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| 136 | |
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| 137 | G4ThreeVector dir(sint*cos(phi),sint*sin(phi), cost); |
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| 138 | dir.rotateUz(direction); |
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| 139 | |
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| 140 | // create G4DynamicParticle objects |
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| 141 | G4DynamicParticle* p1 = |
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| 142 | new G4DynamicParticle(particle,dir,tkin); |
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| 143 | G4DynamicParticle* p2 = |
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| 144 | new G4DynamicParticle(G4Gamma::Gamma(),-dir,egam); |
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| 145 | newp->push_back(p1); |
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| 146 | newp->push_back(p2); |
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| 147 | } |
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| 148 | |
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| 149 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 150 | |
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