[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: G4WentzelVIModel.cc,v 1.32 2009/05/10 16:09:29 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-03-beta-cand-01 $ |
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[968] | 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: G4WentzelVIModel |
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| 35 | // |
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| 36 | // Author: V.Ivanchenko |
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| 37 | // |
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| 38 | // Creation date: 09.04.2008 from G4MuMscModel |
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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 | // Class Description: |
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| 44 | // |
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| 45 | // Implementation of the model of multiple scattering based on |
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| 46 | // G.Wentzel, Z. Phys. 40 (1927) 590. |
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| 47 | // H.W.Lewis, Phys Rev 78 (1950) 526. |
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| 48 | // J.M. Fernandez-Varea et al., NIM B73 (1993) 447. |
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| 49 | // L.Urban, CERN-OPEN-2006-077. |
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| 50 | |
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| 51 | // ------------------------------------------------------------------- |
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| 52 | // |
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| 53 | |
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| 54 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 55 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 56 | |
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| 57 | #include "G4WentzelVIModel.hh" |
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| 58 | #include "Randomize.hh" |
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| 59 | #include "G4LossTableManager.hh" |
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| 60 | #include "G4ParticleChangeForMSC.hh" |
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| 61 | #include "G4PhysicsTableHelper.hh" |
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| 62 | #include "G4ElementVector.hh" |
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| 63 | #include "G4ProductionCutsTable.hh" |
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| 64 | #include "G4PhysicsLogVector.hh" |
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| 65 | #include "G4Electron.hh" |
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| 66 | #include "G4Positron.hh" |
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| 67 | #include "G4Proton.hh" |
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| 68 | |
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| 69 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 70 | |
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[1055] | 71 | G4double G4WentzelVIModel::ScreenRSquare[] = {0.0}; |
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| 72 | G4double G4WentzelVIModel::FormFactor[] = {0.0}; |
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| 73 | |
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[968] | 74 | using namespace std; |
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| 75 | |
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| 76 | G4WentzelVIModel::G4WentzelVIModel(const G4String& nam) : |
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| 77 | G4VMscModel(nam), |
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| 78 | theLambdaTable(0), |
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| 79 | theLambda2Table(0), |
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| 80 | numlimit(0.2), |
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| 81 | nbins(60), |
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| 82 | nwarnings(0), |
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| 83 | nwarnlimit(50), |
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| 84 | currentCouple(0), |
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| 85 | cosThetaMin(1.0), |
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| 86 | q2Limit(TeV*TeV), |
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| 87 | alpha2(fine_structure_const*fine_structure_const), |
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| 88 | isInitialized(false), |
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| 89 | inside(false) |
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| 90 | { |
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| 91 | invsqrt12 = 1./sqrt(12.); |
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| 92 | tlimitminfix = 1.e-6*mm; |
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| 93 | theManager = G4LossTableManager::Instance(); |
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| 94 | fNistManager = G4NistManager::Instance(); |
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| 95 | theElectron = G4Electron::Electron(); |
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| 96 | thePositron = G4Positron::Positron(); |
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| 97 | theProton = G4Proton::Proton(); |
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[1055] | 98 | lowEnergyLimit = 0.1*keV; |
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[968] | 99 | G4double p0 = electron_mass_c2*classic_electr_radius; |
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| 100 | coeff = twopi*p0*p0; |
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| 101 | tkin = targetZ = mom2 = DBL_MIN; |
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| 102 | ecut = etag = DBL_MAX; |
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| 103 | particle = 0; |
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| 104 | nelments = 5; |
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| 105 | xsecn.resize(nelments); |
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| 106 | prob.resize(nelments); |
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[1055] | 107 | |
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| 108 | // Thomas-Fermi screening radii |
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| 109 | // Formfactors from A.V. Butkevich et al., NIM A 488 (2002) 282 |
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| 110 | |
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| 111 | if(0.0 == ScreenRSquare[0]) { |
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| 112 | G4double a0 = electron_mass_c2/0.88534; |
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| 113 | G4double constn = 6.937e-6/(MeV*MeV); |
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| 114 | |
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| 115 | ScreenRSquare[0] = alpha2*a0*a0; |
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| 116 | for(G4int j=1; j<100; j++) { |
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| 117 | G4double x = a0*fNistManager->GetZ13(j); |
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| 118 | ScreenRSquare[j] = alpha2*x*x; |
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| 119 | x = fNistManager->GetA27(j); |
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| 120 | FormFactor[j] = constn*x*x; |
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| 121 | } |
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| 122 | } |
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[968] | 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 | G4WentzelVIModel::~G4WentzelVIModel() |
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| 128 | {} |
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| 129 | |
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| 130 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 131 | |
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| 132 | void G4WentzelVIModel::Initialise(const G4ParticleDefinition* p, |
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| 133 | const G4DataVector& cuts) |
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| 134 | { |
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| 135 | // reset parameters |
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| 136 | SetupParticle(p); |
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| 137 | tkin = targetZ = mom2 = DBL_MIN; |
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| 138 | ecut = etag = DBL_MAX; |
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| 139 | currentRange = 0.0; |
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| 140 | cosThetaMax = cos(PolarAngleLimit()); |
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| 141 | currentCuts = &cuts; |
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| 142 | |
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| 143 | // set values of some data members |
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| 144 | if(!isInitialized) { |
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| 145 | isInitialized = true; |
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[1055] | 146 | fParticleChange = GetParticleChangeForMSC(); |
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| 147 | InitialiseSafetyHelper(); |
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[968] | 148 | } |
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| 149 | } |
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| 150 | |
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| 151 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 152 | |
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| 153 | G4double G4WentzelVIModel::ComputeCrossSectionPerAtom( |
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| 154 | const G4ParticleDefinition* p, |
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| 155 | G4double kinEnergy, |
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| 156 | G4double Z, G4double, |
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| 157 | G4double cutEnergy, G4double) |
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| 158 | { |
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| 159 | SetupParticle(p); |
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| 160 | G4double ekin = std::max(lowEnergyLimit, kinEnergy); |
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| 161 | SetupKinematic(ekin, cutEnergy); |
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| 162 | SetupTarget(Z, ekin); |
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[1055] | 163 | G4double xsec = ComputeTransportXSectionPerAtom(); |
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[968] | 164 | /* |
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| 165 | G4cout << "CS: e= " << tkin << " cosEl= " << cosTetMaxElec2 |
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| 166 | << " cosN= " << cosTetMaxNuc2 << " xsec(bn)= " << xsec/barn |
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| 167 | << " " << particle->GetParticleName() << G4endl; |
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| 168 | */ |
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| 169 | return xsec; |
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| 170 | } |
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| 171 | |
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| 172 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 173 | |
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[1055] | 174 | G4double G4WentzelVIModel::ComputeTransportXSectionPerAtom() |
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[968] | 175 | { |
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| 176 | G4double xSection = 0.0; |
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| 177 | G4double x, y, x1, x2, x3, x4; |
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| 178 | |
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| 179 | // scattering off electrons |
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| 180 | if(cosTetMaxElec2 < 1.0) { |
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| 181 | x = (1.0 - cosTetMaxElec2)/screenZ; |
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| 182 | if(x < numlimit) y = 0.5*x*x*(1.0 - 1.3333333*x + 1.5*x*x); |
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| 183 | else y = log(1.0 + x) - x/(1.0 + x); |
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| 184 | if(y < 0.0) { |
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| 185 | nwarnings++; |
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| 186 | if(nwarnings < nwarnlimit /*&& y < -1.e-10*/) { |
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| 187 | G4cout << "Electron scattering <0 for L1 " << y |
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| 188 | << " e(MeV)= " << tkin << " p(MeV/c)= " << sqrt(mom2) |
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| 189 | << " Z= " << targetZ << " " |
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| 190 | << particle->GetParticleName() << G4endl; |
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| 191 | G4cout << " z= " << 1.0-cosTetMaxElec2 << " screenZ= " << screenZ |
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| 192 | << " x= " << x << G4endl; |
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| 193 | } |
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| 194 | y = 0.0; |
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| 195 | } |
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[1055] | 196 | xSection = y; |
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[968] | 197 | } |
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[1055] | 198 | /* |
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| 199 | G4cout << "G4WentzelVI:XS per A " << " Z= " << targetZ |
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| 200 | << " e(MeV)= " << tkin/MeV << " XSel= " << xSection |
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[968] | 201 | << " cut(MeV)= " << ecut/MeV |
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| 202 | << " zmaxE= " << (1.0 - cosTetMaxElec)/screenZ |
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[1055] | 203 | << " zmaxN= " << (1.0 - cosTetMaxNuc2)/screenZ |
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| 204 | << " costm= " << cosTetMaxNuc2 << G4endl; |
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[968] | 205 | */ |
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| 206 | // scattering off nucleus |
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| 207 | if(cosTetMaxNuc2 < 1.0) { |
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| 208 | x = 1.0 - cosTetMaxNuc2; |
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| 209 | x1 = screenZ*formfactA; |
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[1055] | 210 | x2 = 1.0 - x1; |
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[968] | 211 | x3 = x/screenZ; |
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| 212 | x4 = formfactA*x; |
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| 213 | // low-energy limit |
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| 214 | if(x3 < numlimit && x1 < numlimit) { |
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[1055] | 215 | y = 0.5*x3*x3*(1.0 - 1.3333333*x3 + 1.5*x3*x3 - 1.5*x1 |
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| 216 | + 3.0*x1*x1 + 2.666666*x3*x1)/(x2*x2*x2); |
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[968] | 217 | // high energy limit |
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[1055] | 218 | } else if(x2 <= 0.0) { |
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[968] | 219 | x4 = x1*(1.0 + x3); |
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| 220 | y = x3*(1.0 + 0.5*x3 - (2.0 - x1)*(1.0 + x3 + x3*x3/3.0)/x4)/(x4*x4); |
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| 221 | // middle energy |
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| 222 | } else { |
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| 223 | y = ((1.0 + x1)*x2*log((1. + x3)/(1. + x4)) |
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[1055] | 224 | - x3/(1. + x3) - x4/(1. + x4))/(x2*x2); |
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[968] | 225 | } |
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[1055] | 226 | //G4cout << "y= " << y << " x1= " <<x1<<" x2= " <<x2 |
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| 227 | // <<" x3= "<<x3<<" x4= " << x4<<G4endl; |
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[968] | 228 | if(y < 0.0) { |
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| 229 | nwarnings++; |
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| 230 | if(nwarnings < nwarnlimit /*&& y < -1.e-10*/) { |
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| 231 | G4cout << "Nuclear scattering <0 for L1 " << y |
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| 232 | << " e(MeV)= " << tkin << " Z= " << targetZ << " " |
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| 233 | << particle->GetParticleName() << G4endl; |
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| 234 | G4cout << " formfactA= " << formfactA << " screenZ= " << screenZ |
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| 235 | << " x= " << " x1= " << x1 << " x2= " << x2 |
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| 236 | << " x3= " << x3 << " x4= " << x4 <<G4endl; |
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| 237 | } |
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| 238 | y = 0.0; |
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| 239 | } |
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[1055] | 240 | xSection += y*targetZ; |
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[968] | 241 | } |
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[1055] | 242 | xSection *= kinFactor; |
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| 243 | /* |
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| 244 | G4cout << "Z= " << targetZ << " XStot= " << xSection/barn |
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| 245 | << " screenZ= " << screenZ << " formF= " << formfactA |
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| 246 | << " for " << particle->GetParticleName() |
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| 247 | << " m= " << mass << " 1/v= " << sqrt(invbeta2) << " p= " << sqrt(mom2) |
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| 248 | << " x= " << x |
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| 249 | << G4endl; |
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| 250 | */ |
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[968] | 251 | return xSection; |
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| 252 | } |
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| 253 | |
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| 254 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 255 | |
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| 256 | G4double G4WentzelVIModel::ComputeTruePathLengthLimit( |
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| 257 | const G4Track& track, |
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| 258 | G4PhysicsTable* theTable, |
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| 259 | G4double currentMinimalStep) |
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| 260 | { |
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| 261 | G4double tlimit = currentMinimalStep; |
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| 262 | const G4DynamicParticle* dp = track.GetDynamicParticle(); |
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| 263 | G4StepPoint* sp = track.GetStep()->GetPreStepPoint(); |
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| 264 | G4StepStatus stepStatus = sp->GetStepStatus(); |
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| 265 | |
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| 266 | // initialisation for 1st step |
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| 267 | if(stepStatus == fUndefined) { |
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| 268 | inside = false; |
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| 269 | SetupParticle(dp->GetDefinition()); |
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| 270 | theLambdaTable = theTable; |
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| 271 | } |
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| 272 | |
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| 273 | // initialisation for each step, lambda may be computed from scratch |
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| 274 | preKinEnergy = dp->GetKineticEnergy(); |
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| 275 | DefineMaterial(track.GetMaterialCutsCouple()); |
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| 276 | lambda0 = GetLambda(preKinEnergy); |
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| 277 | currentRange = |
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| 278 | theManager->GetRangeFromRestricteDEDX(particle,preKinEnergy,currentCouple); |
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| 279 | |
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| 280 | // extra check for abnormal situation |
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| 281 | // this check needed to run MSC with eIoni and eBrem inactivated |
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| 282 | if(tlimit > currentRange) tlimit = currentRange; |
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| 283 | |
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| 284 | // stop here if small range particle |
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| 285 | if(inside) return tlimit; |
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| 286 | |
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| 287 | // pre step |
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| 288 | G4double presafety = sp->GetSafety(); |
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| 289 | |
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| 290 | // compute presafety again if presafety <= 0 and no boundary |
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| 291 | // i.e. when it is needed for optimization purposes |
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| 292 | if(stepStatus != fGeomBoundary && presafety < tlimitminfix) |
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[1055] | 293 | presafety = ComputeSafety(sp->GetPosition(), tlimit); |
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[968] | 294 | /* |
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| 295 | G4cout << "G4WentzelVIModel::ComputeTruePathLengthLimit tlimit= " |
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| 296 | <<tlimit<<" safety= " << presafety |
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| 297 | << " range= " <<currentRange<<G4endl; |
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| 298 | */ |
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| 299 | // far from geometry boundary |
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| 300 | if(currentRange < presafety) { |
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| 301 | inside = true; |
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| 302 | |
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| 303 | // limit mean scattering angle |
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| 304 | } else { |
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| 305 | G4double rlimit = facrange*lambda0; |
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| 306 | G4double rcut = currentCouple->GetProductionCuts()->GetProductionCut(1); |
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[1055] | 307 | if(rcut > rlimit) rlimit = std::pow(rcut*rcut*rlimit,0.33333333); |
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| 308 | rlimit = std::min(rlimit, facgeom*currentMaterial->GetRadlen()); |
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[968] | 309 | if(rlimit < tlimit) tlimit = rlimit; |
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| 310 | } |
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| 311 | /* |
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| 312 | G4cout << particle->GetParticleName() << " e= " << preKinEnergy |
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| 313 | << " L0= " << lambda0 << " R= " << currentRange |
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| 314 | << "tlimit= " << tlimit |
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| 315 | << " currentMinimalStep= " << currentMinimalStep << G4endl; |
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| 316 | */ |
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| 317 | return tlimit; |
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| 318 | } |
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| 319 | |
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| 320 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 321 | |
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| 322 | G4double G4WentzelVIModel::ComputeGeomPathLength(G4double truelength) |
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| 323 | { |
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| 324 | tPathLength = truelength; |
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| 325 | zPathLength = tPathLength; |
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| 326 | lambdaeff = lambda0; |
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| 327 | |
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| 328 | if(lambda0 > 0.0) { |
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| 329 | G4double tau = tPathLength/lambda0; |
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| 330 | //G4cout << "ComputeGeomPathLength: tLength= " << tPathLength |
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| 331 | // << " lambda0= " << lambda0 << " tau= " << tau << G4endl; |
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| 332 | // small step |
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| 333 | if(tau < numlimit) { |
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| 334 | zPathLength *= (1.0 - 0.5*tau + tau*tau/6.0); |
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| 335 | |
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| 336 | // medium step |
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| 337 | } else { |
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| 338 | // zPathLength = lambda0*(1.0 - exp(-tPathLength/lambda0)); |
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| 339 | G4double e1 = 0.0; |
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| 340 | if(currentRange > tPathLength) { |
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| 341 | e1 = theManager->GetEnergy(particle, |
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| 342 | currentRange-tPathLength, |
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| 343 | currentCouple); |
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| 344 | } |
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| 345 | lambdaeff = GetLambda(0.5*(e1 + preKinEnergy)); |
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| 346 | zPathLength = lambdaeff*(1.0 - exp(-tPathLength/lambdaeff)); |
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| 347 | } |
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| 348 | } |
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| 349 | //G4cout<<"Comp.geom: zLength= "<<zPathLength<<" tLength= "<<tPathLength<<G4endl; |
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| 350 | return zPathLength; |
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| 351 | } |
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| 352 | |
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| 353 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 354 | |
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| 355 | G4double G4WentzelVIModel::ComputeTrueStepLength(G4double geomStepLength) |
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| 356 | { |
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| 357 | // step defined other than transportation |
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| 358 | if(geomStepLength == zPathLength) return tPathLength; |
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| 359 | |
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| 360 | // step defined by transportation |
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| 361 | tPathLength = geomStepLength; |
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| 362 | zPathLength = geomStepLength; |
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| 363 | G4double tau = zPathLength/lambdaeff; |
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| 364 | tPathLength *= (1.0 + 0.5*tau + tau*tau/3.0); |
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| 365 | |
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| 366 | if(tau > numlimit) { |
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| 367 | G4double e1 = 0.0; |
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| 368 | if(currentRange > tPathLength) { |
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| 369 | e1 = theManager->GetEnergy(particle, |
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| 370 | currentRange-tPathLength, |
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| 371 | currentCouple); |
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| 372 | } |
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| 373 | lambdaeff = GetLambda(0.5*(e1 + preKinEnergy)); |
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| 374 | tau = zPathLength/lambdaeff; |
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| 375 | |
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| 376 | if(tau < 0.999999) tPathLength = -lambdaeff*log(1.0 - tau); |
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| 377 | else tPathLength = currentRange; |
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| 378 | |
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| 379 | if(tPathLength < zPathLength) tPathLength = zPathLength; |
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| 380 | } |
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| 381 | if(tPathLength > currentRange) tPathLength = currentRange; |
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| 382 | //G4cout<<"Comp.true: zLength= "<<zPathLength<<" tLength= "<<tPathLength<<G4endl; |
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| 383 | return tPathLength; |
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| 384 | } |
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| 385 | |
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| 386 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
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| 387 | |
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| 388 | void G4WentzelVIModel::SampleScattering(const G4DynamicParticle* dynParticle, |
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| 389 | G4double safety) |
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| 390 | { |
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| 391 | //G4cout << "!##! G4WentzelVIModel::SampleScattering for " |
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| 392 | // << particle->GetParticleName() << G4endl; |
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| 393 | G4double kinEnergy = dynParticle->GetKineticEnergy(); |
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| 394 | if(kinEnergy <= DBL_MIN || tPathLength <= DBL_MIN) return; |
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| 395 | |
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| 396 | G4double ekin = preKinEnergy; |
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| 397 | if(ekin - kinEnergy > ekin*dtrl) { |
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| 398 | ekin = 0.5*(preKinEnergy + kinEnergy); |
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| 399 | lambdaeff = GetLambda(ekin); |
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| 400 | } |
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| 401 | |
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| 402 | G4double x1 = 0.5*tPathLength/lambdaeff; |
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| 403 | G4double cut= (*currentCuts)[currentMaterialIndex]; |
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| 404 | /* |
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| 405 | G4cout <<"SampleScat: E0(MeV)= "<< preKinEnergy<<" Eeff(MeV)= "<<ekin/MeV |
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| 406 | << " L0= " << lambda0 << " Leff= " << lambdaeff |
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| 407 | << " x1= " << x1 << " safety= " << safety << G4endl; |
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| 408 | */ |
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| 409 | |
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| 410 | G4double xsec = 0.0; |
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| 411 | G4bool largeAng = false; |
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| 412 | |
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| 413 | // large scattering angle case |
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| 414 | if(x1 > 0.5) { |
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| 415 | x1 *= 0.5; |
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| 416 | largeAng = true; |
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| 417 | |
---|
| 418 | // normal case |
---|
| 419 | } else { |
---|
| 420 | |
---|
[1055] | 421 | // define threshold angle between single and multiple scattering |
---|
[968] | 422 | cosThetaMin = 1.0 - 3.0*x1; |
---|
| 423 | |
---|
| 424 | // for low-energy e-,e+ no limit |
---|
| 425 | ekin = std::max(ekin, lowEnergyLimit); |
---|
| 426 | SetupKinematic(ekin, cut); |
---|
| 427 | |
---|
| 428 | // recompute transport cross section |
---|
| 429 | if(cosThetaMin > cosTetMaxNuc) { |
---|
| 430 | |
---|
| 431 | xsec = ComputeXSectionPerVolume(); |
---|
| 432 | |
---|
| 433 | if(xtsec > DBL_MIN) x1 = 0.5*tPathLength*xtsec; |
---|
| 434 | else x1 = 0.0; |
---|
| 435 | |
---|
| 436 | /* |
---|
| 437 | G4cout << "cosTetMaxNuc= " << cosTetMaxNuc |
---|
| 438 | << " cosThetaMin= " << cosThetaMin |
---|
| 439 | << " cosThetaMax= " << cosThetaMax |
---|
| 440 | << " cosTetMaxElec2= " << cosTetMaxElec2 << G4endl; |
---|
| 441 | G4cout << "Recomputed xsec(1/mm)= " << xsec << " x1= " << x1 << G4endl; |
---|
| 442 | */ |
---|
| 443 | } |
---|
| 444 | } |
---|
| 445 | |
---|
| 446 | // result of central part sampling |
---|
| 447 | G4double z; |
---|
| 448 | do { |
---|
| 449 | z = -x1*log(G4UniformRand()); |
---|
| 450 | } while (z > 1.0); |
---|
| 451 | |
---|
| 452 | // cost is sampled ------------------------------ |
---|
| 453 | G4double cost = 1.0 - 2.0*z; |
---|
| 454 | if(cost < -1.0) cost = -1.0; |
---|
| 455 | else if(cost > 1.0) cost = 1.0; |
---|
| 456 | G4double sint = sqrt((1.0 - cost)*(1.0 + cost)); |
---|
| 457 | |
---|
| 458 | G4double phi = twopi*G4UniformRand(); |
---|
| 459 | |
---|
| 460 | G4double dirx = sint*cos(phi); |
---|
| 461 | G4double diry = sint*sin(phi); |
---|
| 462 | |
---|
| 463 | //G4cout << "G4WentzelVIModel: step(mm)= " << tPathLength/mm |
---|
| 464 | // << " sint= " << sint << " cost= " << cost<< G4endl; |
---|
| 465 | |
---|
| 466 | G4ThreeVector oldDirection = dynParticle->GetMomentumDirection(); |
---|
| 467 | G4ThreeVector newDirection(dirx,diry,cost); |
---|
| 468 | G4ThreeVector temp(0.0,0.0,1.0); |
---|
| 469 | G4ThreeVector pos(0.0,0.0,-zPathLength); |
---|
| 470 | G4ThreeVector dir(0.0,0.0,1.0); |
---|
| 471 | G4bool isscat = false; |
---|
| 472 | |
---|
| 473 | // sample MSC scattering for large angle |
---|
| 474 | // extra central scattering for holf step |
---|
| 475 | if(largeAng) { |
---|
| 476 | isscat = true; |
---|
| 477 | pos.setZ(-0.5*zPathLength); |
---|
| 478 | do { |
---|
| 479 | z = -x1*log(G4UniformRand()); |
---|
| 480 | } while (z > 1.0); |
---|
| 481 | cost = 1.0 - 2.0*z; |
---|
| 482 | if(std::abs(cost) > 1.0) cost = 1.0; |
---|
| 483 | |
---|
| 484 | sint = sqrt((1.0 - cost)*(1.0 + cost)); |
---|
| 485 | phi = twopi*G4UniformRand(); |
---|
| 486 | |
---|
| 487 | // position and direction for secondary scattering |
---|
| 488 | dir.set(sint*cos(phi),sint*sin(phi),cost); |
---|
| 489 | pos += 0.5*dir*zPathLength; |
---|
| 490 | x1 *= 2.0; |
---|
| 491 | } |
---|
| 492 | |
---|
| 493 | // sample Reserford scattering for large angle |
---|
| 494 | if(xsec > DBL_MIN) { |
---|
| 495 | G4double t = tPathLength; |
---|
| 496 | G4int nelm = currentMaterial->GetNumberOfElements(); |
---|
| 497 | const G4ElementVector* theElementVector = |
---|
| 498 | currentMaterial->GetElementVector(); |
---|
| 499 | do{ |
---|
| 500 | G4double x = -log(G4UniformRand())/xsec; |
---|
| 501 | pos += dir*(zPathLength*std::min(x,t)/tPathLength); |
---|
| 502 | t -= x; |
---|
| 503 | if(t > 0.0) { |
---|
| 504 | G4double zz1 = 1.0; |
---|
| 505 | G4double qsec = G4UniformRand()*xsec; |
---|
| 506 | |
---|
| 507 | // scattering off nucleus |
---|
| 508 | G4int i = 0; |
---|
| 509 | if(nelm > 1) { |
---|
| 510 | for (; i<nelm; i++) {if(xsecn[i] >= qsec) break;} |
---|
| 511 | if(i >= nelm) i = nelm - 1; |
---|
| 512 | } |
---|
| 513 | SetupTarget((*theElementVector)[i]->GetZ(), tkin); |
---|
| 514 | G4double formf = formfactA; |
---|
| 515 | G4double costm = cosTetMaxNuc2; |
---|
| 516 | if(prob[i] > 0.0) { |
---|
| 517 | if(G4UniformRand() <= prob[i]) { |
---|
| 518 | formf = 0.0; |
---|
| 519 | costm = cosTetMaxElec2; |
---|
| 520 | } |
---|
| 521 | } |
---|
| 522 | if(cosThetaMin > costm) { |
---|
| 523 | |
---|
| 524 | G4double w1 = 1. - cosThetaMin + screenZ; |
---|
| 525 | G4double w2 = 1. - costm + screenZ; |
---|
| 526 | G4double w3 = cosThetaMin - costm; |
---|
| 527 | G4double grej, zz; |
---|
| 528 | do { |
---|
| 529 | zz = w1*w2/(w1 + G4UniformRand()*w3) - screenZ; |
---|
| 530 | grej = 1.0/(1.0 + formf*zz); |
---|
| 531 | } while ( G4UniformRand() > grej*grej ); |
---|
| 532 | if(zz < 0.0) zz = 0.0; |
---|
| 533 | else if(zz > 2.0) zz = 2.0; |
---|
| 534 | zz1 = 1.0 - zz; |
---|
| 535 | } |
---|
| 536 | if(zz1 < 1.0) { |
---|
| 537 | isscat = true; |
---|
| 538 | //G4cout << "Reserford zz1= " << zz1 << " t= " << t << G4endl; |
---|
| 539 | sint = sqrt((1.0 - zz1)*(1.0 + zz1)); |
---|
| 540 | //G4cout << "sint= " << sint << G4endl; |
---|
| 541 | phi = twopi*G4UniformRand(); |
---|
| 542 | G4double vx1 = sint*cos(phi); |
---|
| 543 | G4double vy1 = sint*sin(phi); |
---|
| 544 | temp.set(vx1,vy1,zz1); |
---|
| 545 | temp.rotateUz(dir); |
---|
| 546 | dir = temp; |
---|
| 547 | } |
---|
| 548 | } |
---|
| 549 | } while (t > 0.0); |
---|
| 550 | } |
---|
| 551 | if(isscat) newDirection.rotateUz(dir); |
---|
| 552 | newDirection.rotateUz(oldDirection); |
---|
| 553 | |
---|
| 554 | //G4cout << "G4WentzelVIModel sampling of scattering is done" << G4endl; |
---|
| 555 | // end of sampling ------------------------------- |
---|
| 556 | |
---|
| 557 | fParticleChange->ProposeMomentumDirection(newDirection); |
---|
| 558 | |
---|
| 559 | if (latDisplasment && safety > tlimitminfix) { |
---|
| 560 | G4double rms = invsqrt12*sqrt(2.0*x1); |
---|
| 561 | G4double dx = zPathLength*(0.5*dirx + rms*G4RandGauss::shoot(0.0,1.0)); |
---|
| 562 | G4double dy = zPathLength*(0.5*diry + rms*G4RandGauss::shoot(0.0,1.0)); |
---|
| 563 | G4double dz; |
---|
| 564 | G4double d = (dx*dx + dy*dy)/(zPathLength*zPathLength); |
---|
| 565 | if(d < numlimit) dz = -0.5*zPathLength*d*(1.0 + 0.25*d); |
---|
| 566 | else if(d < 1.0) dz = -zPathLength*(1.0 - sqrt(1.0 - d)); |
---|
| 567 | else { |
---|
| 568 | dx = dy = dz = 0.0; |
---|
| 569 | } |
---|
| 570 | |
---|
| 571 | temp.set(dx,dy,dz); |
---|
| 572 | if(isscat) temp.rotateUz(dir); |
---|
| 573 | pos += temp; |
---|
| 574 | |
---|
| 575 | pos.rotateUz(oldDirection); |
---|
| 576 | |
---|
| 577 | G4double r = pos.mag(); |
---|
| 578 | |
---|
| 579 | /* |
---|
| 580 | G4cout << " r(mm)= " << r << " safety= " << safety |
---|
| 581 | << " trueStep(mm)= " << tPathLength |
---|
| 582 | << " geomStep(mm)= " << zPathLength |
---|
| 583 | << G4endl; |
---|
| 584 | */ |
---|
| 585 | |
---|
| 586 | if(r > tlimitminfix) { |
---|
[1055] | 587 | pos /= r; |
---|
| 588 | ComputeDisplacement(fParticleChange, pos, r, safety); |
---|
[968] | 589 | } |
---|
| 590 | } |
---|
| 591 | //G4cout << "G4WentzelVIModel::SampleScattering end" << G4endl; |
---|
| 592 | } |
---|
| 593 | |
---|
| 594 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 595 | |
---|
| 596 | G4double G4WentzelVIModel::ComputeXSectionPerVolume() |
---|
| 597 | { |
---|
| 598 | const G4ElementVector* theElementVector = |
---|
| 599 | currentMaterial->GetElementVector(); |
---|
| 600 | const G4double* theAtomNumDensityVector = |
---|
| 601 | currentMaterial->GetVecNbOfAtomsPerVolume(); |
---|
| 602 | G4int nelm = currentMaterial->GetNumberOfElements(); |
---|
| 603 | if(nelm > nelments) { |
---|
| 604 | nelments = nelm; |
---|
| 605 | xsecn.resize(nelments); |
---|
| 606 | prob.resize(nelments); |
---|
| 607 | } |
---|
| 608 | |
---|
| 609 | xtsec = 0.0; |
---|
| 610 | G4double xs = 0.0; |
---|
| 611 | |
---|
| 612 | for (G4int i=0; i<nelm; i++) { |
---|
| 613 | SetupTarget((*theElementVector)[i]->GetZ(), tkin); |
---|
| 614 | G4double density = theAtomNumDensityVector[i]; |
---|
| 615 | G4double cosnm = cosTetMaxNuc2; |
---|
| 616 | G4double cosem = cosTetMaxElec2; |
---|
| 617 | |
---|
| 618 | // recompute the angular limit |
---|
| 619 | cosTetMaxNuc2 = std::max(cosnm,cosThetaMin); |
---|
| 620 | cosTetMaxElec2 = std::max(cosem,cosThetaMin); |
---|
[1055] | 621 | xtsec += ComputeTransportXSectionPerAtom()*density; |
---|
[968] | 622 | // return limit back |
---|
| 623 | cosTetMaxElec2 = cosem; |
---|
| 624 | cosTetMaxNuc2 = cosnm; |
---|
| 625 | |
---|
| 626 | G4double esec = 0.0; |
---|
| 627 | G4double nsec = 0.0; |
---|
| 628 | G4double x1 = 1.0 - cosThetaMin + screenZ; |
---|
[1055] | 629 | G4double f = kinFactor*density; |
---|
[968] | 630 | |
---|
| 631 | // scattering off electrons |
---|
| 632 | if(cosThetaMin > cosem) { |
---|
| 633 | esec = f*(cosThetaMin - cosem)/(x1*(1.0 - cosem + screenZ)); |
---|
| 634 | } |
---|
| 635 | |
---|
| 636 | // scattering off nucleaus |
---|
| 637 | if(cosThetaMin > cosnm) { |
---|
| 638 | |
---|
| 639 | // Reserford part |
---|
| 640 | G4double s = screenZ*formfactA; |
---|
| 641 | G4double z1 = 1.0 - cosnm + screenZ; |
---|
[1055] | 642 | G4double s1 = 1.0 - s; |
---|
| 643 | G4double d = s1/formfactA; |
---|
[968] | 644 | |
---|
| 645 | // check numerical limit |
---|
| 646 | if(d < numlimit*x1) { |
---|
| 647 | G4double x2 = x1*x1; |
---|
| 648 | G4double z2 = z1*z1; |
---|
| 649 | nsec = (1.0/(x1*x2) - 1.0/(z1*z2) - d*1.5*(1.0/(x2*x2) - 1.0/(z2*z2)))/ |
---|
| 650 | (3.0*formfactA*formfactA); |
---|
| 651 | } else { |
---|
| 652 | G4double x2 = x1 + d; |
---|
| 653 | G4double z2 = z1 + d; |
---|
[1055] | 654 | nsec = (1.0/x1 - 1.0/z1 + 1.0/x2 - 1.0/z2 - 2.0*log(z1*x2/(z2*x1))/d)/(s1*s1); |
---|
[968] | 655 | } |
---|
| 656 | nsec *= f*targetZ; |
---|
| 657 | } |
---|
| 658 | nsec += esec; |
---|
| 659 | if(nsec > 0.0) esec /= nsec; |
---|
| 660 | xs += nsec; |
---|
| 661 | xsecn[i] = xs; |
---|
| 662 | prob[i] = esec; |
---|
| 663 | //G4cout << i << " xs= " << xs << " cosThetaMin= " << cosThetaMin |
---|
| 664 | // << " costm= " << costm << G4endl; |
---|
| 665 | } |
---|
| 666 | |
---|
| 667 | //G4cout << "ComputeXS result: xsec(1/mm)= " << xs |
---|
| 668 | //<< " txsec(1/mm)= " << xtsec <<G4endl; |
---|
| 669 | return xs; |
---|
| 670 | } |
---|
| 671 | |
---|
| 672 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 673 | |
---|
| 674 | /* |
---|
| 675 | G4double G4MuMscModel::ComputeXSectionPerVolume() |
---|
| 676 | { |
---|
| 677 | const G4ElementVector* theElementVector = |
---|
| 678 | currentMaterial->GetElementVector(); |
---|
| 679 | const G4double* theAtomNumDensityVector = |
---|
| 680 | currentMaterial->GetVecNbOfAtomsPerVolume(); |
---|
| 681 | size_t nelm = currentMaterial->GetNumberOfElements(); |
---|
| 682 | |
---|
| 683 | xsece1 = 0.0; |
---|
| 684 | xsece2 = 0.0; |
---|
| 685 | xsecn2 = 0.0; |
---|
| 686 | zcorr = 0.0; |
---|
| 687 | |
---|
| 688 | G4double fac = coeff*chargeSquare*invbeta2/mom2; |
---|
| 689 | |
---|
| 690 | for (size_t i=0; i<nelm; i++) { |
---|
| 691 | const G4Element* elm = (*theElementVector)[i]; |
---|
| 692 | G4double Z = elm->GetZ(); |
---|
| 693 | SetupTarget(Z, tkin); |
---|
| 694 | G4double den = fac*theAtomNumDensityVector[i]*Z; |
---|
| 695 | |
---|
| 696 | G4double x = 1.0 - cosThetaMin; |
---|
| 697 | G4double x1 = x + screenZ; |
---|
| 698 | G4double x2 = 1.0/(x1*x1); |
---|
| 699 | G4double x3 = 1.0 + x*formfactA; |
---|
| 700 | |
---|
| 701 | //G4cout << "x= " << x << " den= " << den << " cosE= " << cosTetMaxElec << G4endl; |
---|
| 702 | //G4cout << "cosThtaMin= " << cosThetaMin << G4endl; |
---|
| 703 | //G4cout << "cosTetMaxNuc= " << cosTetMaxNuc << " q2Limit= " << q2Limit << G4endl; |
---|
| 704 | |
---|
| 705 | // scattering off electrons |
---|
| 706 | if(cosTetMaxElec < cosThetaMin) { |
---|
| 707 | |
---|
| 708 | // flat part |
---|
| 709 | G4double s = den*x2*x; |
---|
| 710 | xsece1 += s; |
---|
| 711 | zcorr += 0.5*x*s; |
---|
| 712 | |
---|
| 713 | // Reserford part |
---|
| 714 | G4double z1 = 1.0 - cosTetMaxElec + screenZ; |
---|
| 715 | G4double z2 = (cosThetaMin - cosTetMaxElec)/x1; |
---|
| 716 | if(z2 < 0.2) s = z2*(x - 0.5*z2*(x - screenZ))/x1; |
---|
| 717 | else s = log(1.0 + z2) - screenZ*z2/z1; |
---|
| 718 | xsece2 += den*z2/z1; |
---|
| 719 | zcorr += den*s; |
---|
| 720 | } |
---|
| 721 | den *= Z; |
---|
| 722 | |
---|
| 723 | //G4cout << "Z= " << Z<< " cosL= " << cosTetMaxNuc << " cosMin= " << cosThetaMin << G4endl; |
---|
| 724 | // scattering off nucleaus |
---|
| 725 | if(cosTetMaxNuc < cosThetaMin) { |
---|
| 726 | |
---|
| 727 | // flat part |
---|
| 728 | G4double s = den*x2*x/(x3*x3); |
---|
| 729 | xsece1 += s; |
---|
| 730 | zcorr += 0.5*x*s; |
---|
| 731 | |
---|
| 732 | // Reserford part |
---|
| 733 | s = screenZ*formfactA; |
---|
| 734 | G4double w = 1.0 + 2.0*s; |
---|
| 735 | G4double z1 = 1.0 - cosTetMaxNuc + screenZ; |
---|
| 736 | G4double d = (1.0 - s)/formfactA; |
---|
| 737 | G4double x4 = x1 + d; |
---|
| 738 | G4double z4 = z1 + d; |
---|
| 739 | G4double t1 = 1.0/(x1*z1); |
---|
| 740 | G4double t4 = 1.0/(x4*z4); |
---|
| 741 | G4double w1 = cosThetaMin - cosTetMaxNuc; |
---|
| 742 | G4double w2 = log(z1*x4/(x1*z4)); |
---|
| 743 | |
---|
| 744 | den *= w; |
---|
| 745 | xsecn2 += den*(w1*(t1 + t4) - 2.0*w2/d); |
---|
| 746 | zcorr += den*(w*w2 - w1*(screenZ*t1 + t4/formfactA)); |
---|
| 747 | } |
---|
| 748 | xsece[i] = xsece2; |
---|
| 749 | xsecn[i] = xsecn2; |
---|
| 750 | // G4cout << i << " xsece2= " << xsece2 << " xsecn2= " << xsecn2 << G4endl; |
---|
| 751 | } |
---|
| 752 | G4double xsec = xsece1 + xsece2 + xsecn2; |
---|
| 753 | |
---|
| 754 | //G4cout << "xsece1= " << xsece1 << " xsece2= " << xsece2 |
---|
| 755 | //<< " xsecn2= " << xsecn2 |
---|
| 756 | // << " zsec= " << zcorr*0.5*tPathLength << G4endl; |
---|
| 757 | zcorr *= 0.5*tPathLength; |
---|
| 758 | |
---|
| 759 | return xsec; |
---|
| 760 | } |
---|
| 761 | */ |
---|
| 762 | |
---|
| 763 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|
| 764 | |
---|
| 765 | void G4WentzelVIModel::ComputeMaxElectronScattering(G4double cutEnergy) |
---|
| 766 | { |
---|
| 767 | ecut = cutEnergy; |
---|
| 768 | G4double tmax = tkin; |
---|
| 769 | cosTetMaxElec = 1.0; |
---|
| 770 | if(mass > MeV) { |
---|
| 771 | G4double ratio = electron_mass_c2/mass; |
---|
| 772 | G4double tau = tkin/mass; |
---|
| 773 | tmax = 2.0*electron_mass_c2*tau*(tau + 2.)/ |
---|
| 774 | (1.0 + 2.0*ratio*(tau + 1.0) + ratio*ratio); |
---|
| 775 | cosTetMaxElec = 1.0 - std::min(cutEnergy, tmax)*electron_mass_c2/mom2; |
---|
| 776 | } else { |
---|
| 777 | |
---|
| 778 | if(particle == theElectron) tmax *= 0.5; |
---|
| 779 | G4double t = std::min(cutEnergy, tmax); |
---|
| 780 | G4double mom21 = t*(t + 2.0*electron_mass_c2); |
---|
| 781 | G4double t1 = tkin - t; |
---|
| 782 | //G4cout <<"tkin=" <<tkin<<" tmax= "<<tmax<<" t= " |
---|
| 783 | //<<t<< " t1= "<<t1<<" cut= "<<ecut<<G4endl; |
---|
| 784 | if(t1 > 0.0) { |
---|
| 785 | G4double mom22 = t1*(t1 + 2.0*mass); |
---|
| 786 | G4double ctm = (mom2 + mom22 - mom21)*0.5/sqrt(mom2*mom22); |
---|
[1055] | 787 | if(ctm < 1.0) cosTetMaxElec = ctm; |
---|
| 788 | if(ctm < -1.0) cosTetMaxElec = -1.0; |
---|
[968] | 789 | } |
---|
| 790 | } |
---|
| 791 | if(cosTetMaxElec < cosTetMaxNuc) cosTetMaxElec = cosTetMaxNuc; |
---|
| 792 | } |
---|
| 793 | |
---|
| 794 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo...... |
---|