[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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| 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: G4BetheBlochModel.cc,v 1.13 2007/05/22 17:34:36 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 header file |
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| 32 | // |
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| 33 | // |
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| 34 | // File name: G4BetheBlochModel |
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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: 03.01.2002 |
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| 39 | // |
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| 40 | // Modifications: |
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| 41 | // |
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| 42 | // 04-12-02 Fix problem of G4DynamicParticle constructor (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 | // 27-01-03 Make models region aware (V.Ivanchenko) |
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| 45 | // 13-02-03 Add name (V.Ivanchenko) |
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| 46 | // 24-03-05 Add G4EmCorrections (V.Ivanchenko) |
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| 47 | // 11-04-05 Major optimisation of internal interfaces (V.Ivantchenko) |
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| 48 | // 11-02-06 ComputeCrossSectionPerElectron, ComputeCrossSectionPerAtom (mma) |
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| 49 | // 12-02-06 move G4LossTableManager::Instance()->EmCorrections() |
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| 50 | // in constructor (mma) |
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| 51 | // |
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| 52 | // ------------------------------------------------------------------- |
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| 53 | // |
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| 54 | |
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| 55 | |
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| 56 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 57 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 58 | |
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| 59 | #include "G4BetheBlochModel.hh" |
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| 60 | #include "Randomize.hh" |
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| 61 | #include "G4Electron.hh" |
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| 62 | #include "G4LossTableManager.hh" |
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| 63 | #include "G4EmCorrections.hh" |
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| 64 | #include "G4ParticleChangeForLoss.hh" |
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| 65 | |
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| 66 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 67 | |
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| 68 | using namespace std; |
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| 69 | |
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| 70 | G4BetheBlochModel::G4BetheBlochModel(const G4ParticleDefinition* p, |
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| 71 | const G4String& nam) |
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| 72 | : G4VEmModel(nam), |
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| 73 | particle(0), |
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| 74 | tlimit(DBL_MAX), |
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| 75 | twoln10(2.0*log(10.0)), |
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| 76 | bg2lim(0.0169), |
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| 77 | taulim(8.4146e-3), |
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| 78 | isIon(false) |
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| 79 | { |
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| 80 | if(p) SetParticle(p); |
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| 81 | theElectron = G4Electron::Electron(); |
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| 82 | corr = G4LossTableManager::Instance()->EmCorrections(); |
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| 83 | } |
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| 84 | |
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| 85 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 86 | |
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| 87 | G4BetheBlochModel::~G4BetheBlochModel() |
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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 G4BetheBlochModel::MinEnergyCut(const G4ParticleDefinition*, |
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| 93 | const G4MaterialCutsCouple* couple) |
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| 94 | { |
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| 95 | return couple->GetMaterial()->GetIonisation()->GetMeanExcitationEnergy(); |
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| 96 | } |
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| 97 | |
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| 98 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 99 | |
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| 100 | void G4BetheBlochModel::Initialise(const G4ParticleDefinition* p, |
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| 101 | const G4DataVector&) |
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| 102 | { |
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| 103 | if (!particle) SetParticle(p); |
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| 104 | G4String pname = particle->GetParticleName(); |
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| 105 | if (particle->GetParticleType() == "nucleus" && |
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| 106 | pname != "deuteron" && pname != "triton") isIon = true; |
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| 107 | |
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| 108 | if (pParticleChange) |
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| 109 | fParticleChange = reinterpret_cast<G4ParticleChangeForLoss*> |
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| 110 | (pParticleChange); |
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| 111 | else |
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| 112 | fParticleChange = new G4ParticleChangeForLoss(); |
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| 113 | } |
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| 114 | |
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| 115 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 116 | |
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| 117 | G4double G4BetheBlochModel::ComputeCrossSectionPerElectron( |
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| 118 | const G4ParticleDefinition* p, |
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| 119 | G4double kineticEnergy, |
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| 120 | G4double cutEnergy, |
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| 121 | G4double maxKinEnergy) |
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| 122 | { |
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| 123 | G4double cross = 0.0; |
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| 124 | G4double tmax = MaxSecondaryEnergy(p, kineticEnergy); |
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| 125 | G4double maxEnergy = min(tmax,maxKinEnergy); |
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| 126 | if(cutEnergy < maxEnergy) { |
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| 127 | |
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| 128 | G4double totEnergy = kineticEnergy + mass; |
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| 129 | G4double energy2 = totEnergy*totEnergy; |
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| 130 | G4double beta2 = kineticEnergy*(kineticEnergy + 2.0*mass)/energy2; |
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| 131 | |
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| 132 | cross = 1.0/cutEnergy - 1.0/maxEnergy - beta2*log(maxEnergy/cutEnergy)/tmax; |
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| 133 | |
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| 134 | // +term for spin=1/2 particle |
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| 135 | if( 0.5 == spin ) cross += 0.5*(maxEnergy - cutEnergy)/energy2; |
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| 136 | |
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| 137 | cross *= twopi_mc2_rcl2*chargeSquare/beta2; |
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| 138 | } |
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| 139 | |
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| 140 | // G4cout << "BB: e= " << kineticEnergy << " tmin= " << cutEnergy |
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| 141 | // << " tmax= " << tmax << " cross= " << cross << G4endl; |
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| 142 | |
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| 143 | return cross; |
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| 144 | } |
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| 145 | |
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| 146 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 147 | |
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| 148 | G4double G4BetheBlochModel::ComputeCrossSectionPerAtom( |
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| 149 | const G4ParticleDefinition* p, |
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| 150 | G4double kineticEnergy, |
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| 151 | G4double Z, G4double, |
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| 152 | G4double cutEnergy, |
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| 153 | G4double maxEnergy) |
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| 154 | { |
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| 155 | G4double cross = Z*ComputeCrossSectionPerElectron |
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| 156 | (p,kineticEnergy,cutEnergy,maxEnergy); |
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| 157 | return cross; |
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| 158 | } |
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| 159 | |
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| 160 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 161 | |
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| 162 | G4double G4BetheBlochModel::CrossSectionPerVolume( |
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| 163 | const G4Material* material, |
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| 164 | const G4ParticleDefinition* p, |
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| 165 | G4double kineticEnergy, |
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| 166 | G4double cutEnergy, |
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| 167 | G4double maxEnergy) |
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| 168 | { |
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| 169 | G4double eDensity = material->GetElectronDensity(); |
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| 170 | G4double cross = eDensity*ComputeCrossSectionPerElectron |
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| 171 | (p,kineticEnergy,cutEnergy,maxEnergy); |
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| 172 | return cross; |
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| 173 | } |
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| 174 | |
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| 175 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 176 | |
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| 177 | G4double G4BetheBlochModel::ComputeDEDXPerVolume(const G4Material* material, |
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| 178 | const G4ParticleDefinition* p, |
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| 179 | G4double kineticEnergy, |
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| 180 | G4double cut) |
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| 181 | { |
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| 182 | G4double tmax = MaxSecondaryEnergy(p, kineticEnergy); |
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| 183 | G4double cutEnergy = min(cut,tmax); |
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| 184 | |
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| 185 | G4double tau = kineticEnergy/mass; |
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| 186 | G4double gam = tau + 1.0; |
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| 187 | G4double bg2 = tau * (tau+2.0); |
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| 188 | G4double beta2 = bg2/(gam*gam); |
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| 189 | |
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| 190 | G4double eexc = material->GetIonisation()->GetMeanExcitationEnergy(); |
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| 191 | G4double eexc2 = eexc*eexc; |
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| 192 | G4double cden = material->GetIonisation()->GetCdensity(); |
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| 193 | G4double mden = material->GetIonisation()->GetMdensity(); |
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| 194 | G4double aden = material->GetIonisation()->GetAdensity(); |
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| 195 | G4double x0den = material->GetIonisation()->GetX0density(); |
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| 196 | G4double x1den = material->GetIonisation()->GetX1density(); |
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| 197 | |
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| 198 | G4double eDensity = material->GetElectronDensity(); |
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| 199 | |
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| 200 | G4double dedx = log(2.0*electron_mass_c2*bg2*cutEnergy/eexc2) |
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| 201 | - (1.0 + cutEnergy/tmax)*beta2; |
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| 202 | |
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| 203 | if(0.5 == spin) { |
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| 204 | G4double del = 0.5*cutEnergy/(kineticEnergy + mass); |
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| 205 | dedx += del*del; |
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| 206 | } |
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| 207 | |
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| 208 | // density correction |
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| 209 | G4double x = log(bg2)/twoln10; |
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| 210 | if ( x >= x0den ) { |
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| 211 | dedx -= twoln10*x - cden ; |
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| 212 | if ( x < x1den ) dedx -= aden*pow((x1den-x),mden) ; |
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| 213 | } |
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| 214 | |
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| 215 | // shell correction |
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| 216 | dedx -= 2.0*corr->ShellCorrection(p,material,kineticEnergy); |
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| 217 | |
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| 218 | // now compute the total ionization loss |
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| 219 | |
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| 220 | if (dedx < 0.0) dedx = 0.0 ; |
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| 221 | |
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| 222 | dedx *= twopi_mc2_rcl2*chargeSquare*eDensity/beta2; |
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| 223 | |
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| 224 | //High order correction only for hadrons |
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| 225 | if(!isIon) dedx += corr->HighOrderCorrections(p,material,kineticEnergy); |
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| 226 | |
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| 227 | return dedx; |
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| 228 | } |
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| 229 | |
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| 230 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 231 | |
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| 232 | void G4BetheBlochModel::SampleSecondaries(vector<G4DynamicParticle*>* vdp, |
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| 233 | const G4MaterialCutsCouple*, |
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| 234 | const G4DynamicParticle* dp, |
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| 235 | G4double minKinEnergy, |
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| 236 | G4double maxEnergy) |
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| 237 | { |
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| 238 | G4double kineticEnergy = dp->GetKineticEnergy(); |
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| 239 | G4double tmax = MaxSecondaryEnergy(dp->GetDefinition(),kineticEnergy); |
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| 240 | |
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| 241 | G4double maxKinEnergy = min(maxEnergy,tmax); |
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| 242 | if(minKinEnergy >= maxKinEnergy) return; |
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| 243 | |
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| 244 | G4double totEnergy = kineticEnergy + mass; |
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| 245 | G4double etot2 = totEnergy*totEnergy; |
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| 246 | G4double beta2 = kineticEnergy*(kineticEnergy + 2.0*mass)/etot2; |
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| 247 | |
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| 248 | G4double deltaKinEnergy, f; |
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| 249 | |
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| 250 | // sampling follows ... |
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| 251 | do { |
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| 252 | G4double q = G4UniformRand(); |
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| 253 | deltaKinEnergy = minKinEnergy*maxKinEnergy |
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| 254 | /(minKinEnergy*(1.0 - q) + maxKinEnergy*q); |
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| 255 | |
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| 256 | f = 1.0 - beta2*deltaKinEnergy/tmax; |
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| 257 | if( 0.5 == spin ) f += 0.5*deltaKinEnergy*deltaKinEnergy/etot2; |
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| 258 | |
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| 259 | if(f > 1.0) { |
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| 260 | G4cout << "G4BetheBlochModel::SampleSecondary Warning! " |
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| 261 | << "Majorant 1.0 < " |
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| 262 | << f << " for Edelta= " << deltaKinEnergy |
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| 263 | << G4endl; |
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| 264 | } |
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| 265 | |
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| 266 | } while( G4UniformRand() > f ); |
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| 267 | |
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| 268 | G4double totMomentum = totEnergy*sqrt(beta2); |
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| 269 | G4double deltaMomentum = |
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| 270 | sqrt(deltaKinEnergy * (deltaKinEnergy + 2.0*electron_mass_c2)); |
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| 271 | G4double cost = deltaKinEnergy * (totEnergy + electron_mass_c2) / |
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| 272 | (deltaMomentum * totMomentum); |
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| 273 | if(cost > 1.0) { |
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| 274 | G4cout << "### G4BetheBlochModel WARNING: cost= " |
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| 275 | << cost << " > 1 for " |
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| 276 | << dp->GetDefinition()->GetParticleName() |
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| 277 | << " Ekin(MeV)= " << kineticEnergy |
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| 278 | << " p(MeV/c)= " << totMomentum |
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| 279 | << " delEkin(MeV)= " << deltaKinEnergy |
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| 280 | << " delMom(MeV/c)= " << deltaMomentum |
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| 281 | << " tmin(MeV)= " << minKinEnergy |
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| 282 | << " tmax(MeV)= " << maxKinEnergy |
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| 283 | << " dir= " << dp->GetMomentumDirection() |
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| 284 | << G4endl; |
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| 285 | cost = 1.0; |
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| 286 | } |
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| 287 | G4double sint = sqrt((1.0 - cost)*(1.0 + cost)); |
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| 288 | |
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| 289 | G4double phi = twopi * G4UniformRand() ; |
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| 290 | |
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| 291 | |
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| 292 | G4ThreeVector deltaDirection(sint*cos(phi),sint*sin(phi), cost); |
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| 293 | G4ThreeVector direction = dp->GetMomentumDirection(); |
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| 294 | deltaDirection.rotateUz(direction); |
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| 295 | |
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| 296 | // create G4DynamicParticle object for delta ray |
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| 297 | G4DynamicParticle* delta = new G4DynamicParticle(theElectron, |
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| 298 | deltaDirection,deltaKinEnergy); |
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| 299 | |
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| 300 | vdp->push_back(delta); |
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| 301 | |
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| 302 | // Change kinematics of primary particle |
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| 303 | kineticEnergy -= deltaKinEnergy; |
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| 304 | G4ThreeVector finalP = direction*totMomentum - deltaDirection*deltaMomentum; |
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| 305 | finalP = finalP.unit(); |
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| 306 | |
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| 307 | fParticleChange->SetProposedKineticEnergy(kineticEnergy); |
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| 308 | fParticleChange->SetProposedMomentumDirection(finalP); |
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| 309 | } |
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| 310 | |
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| 311 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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