| [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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| [1007] | 26 | // $Id: G4LivermorePolarizedComptonModel.cc,v 1.1 2008/10/30 14:16:35 sincerti Exp $
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| 27 | // GEANT4 tag $Name: geant4-09-02 $
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| [968] | 28 | //
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| 29 |
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| 30 | #include "G4LivermorePolarizedComptonModel.hh"
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| 31 |
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| 32 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 33 |
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| 34 | using namespace std;
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| 35 |
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| 36 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 37 |
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| 38 | G4LivermorePolarizedComptonModel::G4LivermorePolarizedComptonModel(const G4ParticleDefinition*,
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| 39 | const G4String& nam)
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| [1007] | 40 | :G4VEmModel(nam),isInitialised(false)
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| [968] | 41 | {
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| 42 | lowEnergyLimit = 250 * eV; // SI - Could be 10 eV ?
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| 43 | highEnergyLimit = 100 * GeV;
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| 44 | SetLowEnergyLimit(lowEnergyLimit);
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| 45 | SetHighEnergyLimit(highEnergyLimit);
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| 46 |
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| 47 | verboseLevel= 0;
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| 48 | // Verbosity scale:
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| 49 | // 0 = nothing
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| 50 | // 1 = warning for energy non-conservation
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| 51 | // 2 = details of energy budget
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| 52 | // 3 = calculation of cross sections, file openings, sampling of atoms
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| 53 | // 4 = entering in methods
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| 54 |
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| 55 | G4cout << "Livermore Polarized Compton is constructed " << G4endl
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| 56 | << "Energy range: "
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| 57 | << lowEnergyLimit / keV << " keV - "
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| 58 | << highEnergyLimit / GeV << " GeV"
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| 59 | << G4endl;
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| 60 |
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| 61 | }
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| 62 |
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| 63 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 64 |
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| 65 | G4LivermorePolarizedComptonModel::~G4LivermorePolarizedComptonModel()
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| 66 | {
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| [1007] | 67 | delete meanFreePathTable;
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| 68 | delete crossSectionHandler;
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| 69 | delete scatterFunctionData;
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| [968] | 70 | }
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| 71 |
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| 72 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 73 |
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| 74 | void G4LivermorePolarizedComptonModel::Initialise(const G4ParticleDefinition* particle,
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| 75 | const G4DataVector& cuts)
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| 76 | {
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| 77 | if (verboseLevel > 3)
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| 78 | G4cout << "Calling G4LivermorePolarizedComptonModel::Initialise()" << G4endl;
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| 79 |
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| [1007] | 80 | InitialiseElementSelectors(particle,cuts);
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| [968] | 81 |
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| 82 | // Energy limits
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| 83 |
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| 84 | if (LowEnergyLimit() < lowEnergyLimit)
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| 85 | {
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| 86 | G4cout << "G4LivermorePolarizedComptonModel: low energy limit increased from " <<
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| 87 | LowEnergyLimit()/eV << " eV to " << lowEnergyLimit << " eV" << G4endl;
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| 88 | SetLowEnergyLimit(lowEnergyLimit);
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| 89 | }
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| 90 |
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| 91 | if (HighEnergyLimit() > highEnergyLimit)
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| 92 | {
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| 93 | G4cout << "G4LivermorePolarizedComptonModel: high energy limit decreased from " <<
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| 94 | HighEnergyLimit()/GeV << " GeV to " << highEnergyLimit << " GeV" << G4endl;
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| 95 | SetHighEnergyLimit(highEnergyLimit);
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| 96 | }
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| 97 |
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| 98 | // Reading of data files - all materials are read
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| 99 |
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| 100 | crossSectionHandler = new G4CrossSectionHandler;
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| 101 | crossSectionHandler->Clear();
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| 102 | G4String crossSectionFile = "comp/ce-cs-";
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| 103 | crossSectionHandler->LoadData(crossSectionFile);
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| 104 |
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| 105 | meanFreePathTable = 0;
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| 106 | meanFreePathTable = crossSectionHandler->BuildMeanFreePathForMaterials();
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| 107 |
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| 108 | G4VDataSetAlgorithm* scatterInterpolation = new G4LogLogInterpolation;
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| 109 | G4String scatterFile = "comp/ce-sf-";
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| 110 | scatterFunctionData = new G4CompositeEMDataSet(scatterInterpolation, 1., 1.);
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| 111 | scatterFunctionData->LoadData(scatterFile);
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| 112 |
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| 113 | // For Doppler broadening
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| 114 | shellData.SetOccupancyData();
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| 115 | G4String file = "/doppler/shell-doppler";
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| 116 | shellData.LoadData(file);
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| 117 |
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| 118 | //
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| 119 | if (verboseLevel > 2)
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| 120 | G4cout << "Loaded cross section files for Livermore Polarized Compton model" << G4endl;
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| 121 |
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| 122 | G4cout << "Livermore Polarized Compton model is initialized " << G4endl
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| 123 | << "Energy range: "
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| 124 | << LowEnergyLimit() / keV << " keV - "
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| 125 | << HighEnergyLimit() / GeV << " GeV"
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| 126 | << G4endl;
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| 127 |
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| 128 | //
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| 129 |
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| 130 | if(isInitialised) return;
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| 131 |
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| 132 | if(pParticleChange)
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| 133 | fParticleChange = reinterpret_cast<G4ParticleChangeForGamma*>(pParticleChange);
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| 134 | else
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| 135 | fParticleChange = new G4ParticleChangeForGamma();
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| 136 |
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| 137 | isInitialised = true;
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| 138 | }
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| 139 |
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| 140 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 141 |
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| 142 | G4double G4LivermorePolarizedComptonModel::ComputeCrossSectionPerAtom(
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| 143 | const G4ParticleDefinition*,
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| 144 | G4double GammaEnergy,
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| 145 | G4double Z, G4double,
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| 146 | G4double, G4double)
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| 147 | {
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| 148 | if (verboseLevel > 3)
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| 149 | G4cout << "Calling ComputeCrossSectionPerAtom() of G4LivermorePolarizedComptonModel" << G4endl;
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| 150 |
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| 151 | G4double cs = crossSectionHandler->FindValue(G4int(Z), GammaEnergy);
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| 152 | return cs;
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| 153 | }
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| 154 |
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| 155 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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| 156 |
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| 157 | void G4LivermorePolarizedComptonModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
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| 158 | const G4MaterialCutsCouple* couple,
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| 159 | const G4DynamicParticle* aDynamicGamma,
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| 160 | G4double,
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| 161 | G4double)
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| 162 | {
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| 163 | // The scattered gamma energy is sampled according to Klein - Nishina formula.
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| 164 | // The random number techniques of Butcher & Messel are used (Nuc Phys 20(1960),15).
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| 165 | // GEANT4 internal units
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| 166 | //
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| 167 | // Note : Effects due to binding of atomic electrons are negliged.
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| 168 |
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| 169 | if (verboseLevel > 3)
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| 170 | G4cout << "Calling SampleSecondaries() of G4LivermorePolarizedComptonModel" << G4endl;
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| 171 |
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| 172 | G4double gammaEnergy0 = aDynamicGamma->GetKineticEnergy();
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| 173 | G4ThreeVector gammaPolarization0 = aDynamicGamma->GetPolarization();
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| 174 |
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| 175 | // Protection: a polarisation parallel to the
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| 176 | // direction causes problems;
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| 177 | // in that case find a random polarization
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| 178 |
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| 179 | G4ThreeVector gammaDirection0 = aDynamicGamma->GetMomentumDirection();
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| 180 |
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| 181 | // Make sure that the polarization vector is perpendicular to the
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| 182 | // gamma direction. If not
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| 183 |
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| 184 | if(!(gammaPolarization0.isOrthogonal(gammaDirection0, 1e-6))||(gammaPolarization0.mag()==0))
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| 185 | { // only for testing now
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| 186 | gammaPolarization0 = GetRandomPolarization(gammaDirection0);
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| 187 | }
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| 188 | else
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| 189 | {
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| 190 | if ( gammaPolarization0.howOrthogonal(gammaDirection0) != 0)
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| 191 | {
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| 192 | gammaPolarization0 = GetPerpendicularPolarization(gammaDirection0, gammaPolarization0);
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| 193 | }
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| 194 | }
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| 195 |
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| 196 | // End of Protection
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| 197 |
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| 198 | // Within energy limit?
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| 199 |
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| 200 | if(gammaEnergy0 <= lowEnergyLimit)
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| 201 | {
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| 202 | fParticleChange->ProposeTrackStatus(fStopAndKill);
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| 203 | fParticleChange->SetProposedKineticEnergy(0.);
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| 204 | fParticleChange->ProposeLocalEnergyDeposit(gammaEnergy0);
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| [1007] | 205 | // SI - IS THE FOLLOWING RETURN NECESSARY ?
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| [968] | 206 | return;
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| 207 | }
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| 208 |
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| 209 | G4double E0_m = gammaEnergy0 / electron_mass_c2 ;
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| 210 |
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| 211 | // Select randomly one element in the current material
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| 212 |
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| 213 | G4int Z = crossSectionHandler->SelectRandomAtom(couple,gammaEnergy0);
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| 214 |
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| 215 | // Sample the energy and the polarization of the scattered photon
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| 216 |
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| 217 | G4double epsilon, epsilonSq, onecost, sinThetaSqr, greject ;
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| 218 |
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| 219 | G4double epsilon0 = 1./(1. + 2*E0_m);
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| 220 | G4double epsilon0Sq = epsilon0*epsilon0;
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| 221 | G4double alpha1 = - std::log(epsilon0);
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| 222 | G4double alpha2 = 0.5*(1.- epsilon0Sq);
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| 223 |
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| 224 | G4double wlGamma = h_Planck*c_light/gammaEnergy0;
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| 225 | G4double gammaEnergy1;
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| 226 | G4ThreeVector gammaDirection1;
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| 227 |
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| 228 | do {
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| 229 | if ( alpha1/(alpha1+alpha2) > G4UniformRand() )
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| 230 | {
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| 231 | epsilon = std::exp(-alpha1*G4UniformRand());
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| 232 | epsilonSq = epsilon*epsilon;
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| 233 | }
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| 234 | else
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| 235 | {
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| 236 | epsilonSq = epsilon0Sq + (1.- epsilon0Sq)*G4UniformRand();
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| 237 | epsilon = std::sqrt(epsilonSq);
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| 238 | }
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| 239 |
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| 240 | onecost = (1.- epsilon)/(epsilon*E0_m);
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| 241 | sinThetaSqr = onecost*(2.-onecost);
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| 242 |
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| 243 | // Protection
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| 244 | if (sinThetaSqr > 1.)
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| 245 | {
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| 246 | G4cout
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| 247 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
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| 248 | << "sin(theta)**2 = "
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| 249 | << sinThetaSqr
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| 250 | << "; set to 1"
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| 251 | << G4endl;
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| 252 | sinThetaSqr = 1.;
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| 253 | }
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| 254 | if (sinThetaSqr < 0.)
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| 255 | {
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| 256 | G4cout
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| 257 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
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| 258 | << "sin(theta)**2 = "
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| 259 | << sinThetaSqr
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| 260 | << "; set to 0"
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| 261 | << G4endl;
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| 262 | sinThetaSqr = 0.;
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| 263 | }
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| 264 | // End protection
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| 265 |
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| 266 | G4double x = std::sqrt(onecost/2.) / (wlGamma/cm);;
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| 267 | G4double scatteringFunction = scatterFunctionData->FindValue(x,Z-1);
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| 268 | greject = (1. - epsilon*sinThetaSqr/(1.+ epsilonSq))*scatteringFunction;
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| 269 |
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| 270 | } while(greject < G4UniformRand()*Z);
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| 271 |
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| 272 |
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| 273 | // ****************************************************
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| 274 | // Phi determination
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| 275 | // ****************************************************
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| 276 |
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| 277 | G4double phi = SetPhi(epsilon,sinThetaSqr);
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| 278 |
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| 279 | //
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| 280 | // scattered gamma angles. ( Z - axis along the parent gamma)
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| 281 | //
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| 282 |
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| 283 | G4double cosTheta = 1. - onecost;
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| 284 |
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| 285 | // Protection
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| 286 |
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| 287 | if (cosTheta > 1.)
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| 288 | {
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| 289 | G4cout
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| 290 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
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| 291 | << "cosTheta = "
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| 292 | << cosTheta
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| 293 | << "; set to 1"
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| 294 | << G4endl;
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| 295 | cosTheta = 1.;
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| 296 | }
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| 297 | if (cosTheta < -1.)
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| 298 | {
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| 299 | G4cout
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| 300 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
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| 301 | << "cosTheta = "
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| 302 | << cosTheta
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| 303 | << "; set to -1"
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| 304 | << G4endl;
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| 305 | cosTheta = -1.;
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| 306 | }
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| 307 | // End protection
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| 308 |
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| 309 |
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| 310 | G4double sinTheta = std::sqrt (sinThetaSqr);
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| 311 |
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| 312 | // Protection
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| 313 | if (sinTheta > 1.)
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| 314 | {
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| 315 | G4cout
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| 316 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
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| 317 | << "sinTheta = "
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| 318 | << sinTheta
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| 319 | << "; set to 1"
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| 320 | << G4endl;
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| 321 | sinTheta = 1.;
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| 322 | }
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| 323 | if (sinTheta < -1.)
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| 324 | {
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| 325 | G4cout
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| 326 | << " -- Warning -- G4LivermorePolarizedComptonModel::SampleSecondaries "
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| 327 | << "sinTheta = "
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| 328 | << sinTheta
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| 329 | << "; set to -1"
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| 330 | << G4endl;
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| 331 | sinTheta = -1.;
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| 332 | }
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| 333 | // End protection
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| 334 |
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| 335 |
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| 336 | G4double dirx = sinTheta*std::cos(phi);
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| 337 | G4double diry = sinTheta*std::sin(phi);
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| 338 | G4double dirz = cosTheta ;
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| 339 |
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| 340 |
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| 341 | // oneCosT , eom
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| 342 |
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| 343 | // Doppler broadening - Method based on:
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| 344 | // Y. Namito, S. Ban and H. Hirayama,
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| 345 | // "Implementation of the Doppler Broadening of a Compton-Scattered Photon Into the EGS4 Code"
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| 346 | // NIM A 349, pp. 489-494, 1994
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| 347 |
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| 348 | // Maximum number of sampling iterations
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| 349 |
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| 350 | G4int maxDopplerIterations = 1000;
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| 351 | G4double bindingE = 0.;
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| 352 | G4double photonEoriginal = epsilon * gammaEnergy0;
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| 353 | G4double photonE = -1.;
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| 354 | G4int iteration = 0;
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| 355 | G4double eMax = gammaEnergy0;
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| 356 |
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| 357 | do
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| 358 | {
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| 359 | iteration++;
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| 360 | // Select shell based on shell occupancy
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| 361 | G4int shell = shellData.SelectRandomShell(Z);
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| 362 | bindingE = shellData.BindingEnergy(Z,shell);
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| 363 |
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| 364 | eMax = gammaEnergy0 - bindingE;
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| 365 |
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| 366 | // Randomly sample bound electron momentum (memento: the data set is in Atomic Units)
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| 367 | G4double pSample = profileData.RandomSelectMomentum(Z,shell);
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| 368 | // Rescale from atomic units
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| 369 | G4double pDoppler = pSample * fine_structure_const;
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| 370 | G4double pDoppler2 = pDoppler * pDoppler;
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| 371 | G4double var2 = 1. + onecost * E0_m;
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| 372 | G4double var3 = var2*var2 - pDoppler2;
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| 373 | G4double var4 = var2 - pDoppler2 * cosTheta;
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| 374 | G4double var = var4*var4 - var3 + pDoppler2 * var3;
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| 375 | if (var > 0.)
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| 376 | {
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| 377 | G4double varSqrt = std::sqrt(var);
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| 378 | G4double scale = gammaEnergy0 / var3;
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| 379 | // Random select either root
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| 380 | if (G4UniformRand() < 0.5) photonE = (var4 - varSqrt) * scale;
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| 381 | else photonE = (var4 + varSqrt) * scale;
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| 382 | }
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| 383 | else
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| 384 | {
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| 385 | photonE = -1.;
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| 386 | }
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| 387 | } while ( iteration <= maxDopplerIterations &&
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| 388 | (photonE < 0. || photonE > eMax || photonE < eMax*G4UniformRand()) );
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| 389 |
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| 390 | // End of recalculation of photon energy with Doppler broadening
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| 391 | // Revert to original if maximum number of iterations threshold has been reached
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| 392 | if (iteration >= maxDopplerIterations)
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| 393 | {
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| 394 | photonE = photonEoriginal;
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| 395 | bindingE = 0.;
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| 396 | }
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| 397 |
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| 398 | gammaEnergy1 = photonE;
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| 399 |
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| 400 | //
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| 401 | // update G4VParticleChange for the scattered photon
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| 402 | //
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| 403 |
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| 404 | // gammaEnergy1 = epsilon*gammaEnergy0;
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| 405 |
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| 406 |
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| 407 | // New polarization
|
|---|
| 408 |
|
|---|
| 409 | G4ThreeVector gammaPolarization1 = SetNewPolarization(epsilon,
|
|---|
| 410 | sinThetaSqr,
|
|---|
| 411 | phi,
|
|---|
| 412 | cosTheta);
|
|---|
| 413 |
|
|---|
| 414 | // Set new direction
|
|---|
| 415 | G4ThreeVector tmpDirection1( dirx,diry,dirz );
|
|---|
| 416 | gammaDirection1 = tmpDirection1;
|
|---|
| 417 |
|
|---|
| 418 | // Change reference frame.
|
|---|
| 419 |
|
|---|
| 420 | SystemOfRefChange(gammaDirection0,gammaDirection1,
|
|---|
| 421 | gammaPolarization0,gammaPolarization1);
|
|---|
| 422 |
|
|---|
| 423 | if (gammaEnergy1 > 0.)
|
|---|
| 424 | {
|
|---|
| 425 | fParticleChange->SetProposedKineticEnergy( gammaEnergy1 ) ;
|
|---|
| 426 | fParticleChange->ProposeMomentumDirection( gammaDirection1 );
|
|---|
| 427 | fParticleChange->ProposePolarization( gammaPolarization1 );
|
|---|
| 428 | }
|
|---|
| 429 | else
|
|---|
| 430 | {
|
|---|
| 431 | fParticleChange->SetProposedKineticEnergy(0.) ;
|
|---|
| 432 | fParticleChange->ProposeTrackStatus(fStopAndKill);
|
|---|
| 433 | }
|
|---|
| 434 |
|
|---|
| 435 | //
|
|---|
| 436 | // kinematic of the scattered electron
|
|---|
| 437 | //
|
|---|
| 438 |
|
|---|
| 439 | G4double ElecKineEnergy = gammaEnergy0 - gammaEnergy1 -bindingE;
|
|---|
| 440 |
|
|---|
| 441 | // SI - Removed range test
|
|---|
| 442 |
|
|---|
| 443 | G4double ElecMomentum = std::sqrt(ElecKineEnergy*(ElecKineEnergy+2.*electron_mass_c2));
|
|---|
| 444 |
|
|---|
| 445 | G4ThreeVector ElecDirection((gammaEnergy0 * gammaDirection0 -
|
|---|
| 446 | gammaEnergy1 * gammaDirection1) * (1./ElecMomentum));
|
|---|
| 447 |
|
|---|
| 448 | fParticleChange->ProposeLocalEnergyDeposit(bindingE);
|
|---|
| 449 |
|
|---|
| 450 | G4DynamicParticle* dp = new G4DynamicParticle (G4Electron::Electron(),ElecDirection.unit(),ElecKineEnergy) ;
|
|---|
| 451 | fvect->push_back(dp);
|
|---|
| 452 |
|
|---|
| 453 | }
|
|---|
| 454 |
|
|---|
| 455 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 456 |
|
|---|
| 457 | G4double G4LivermorePolarizedComptonModel::SetPhi(G4double energyRate,
|
|---|
| 458 | G4double sinSqrTh)
|
|---|
| 459 | {
|
|---|
| 460 | G4double rand1;
|
|---|
| 461 | G4double rand2;
|
|---|
| 462 | G4double phiProbability;
|
|---|
| 463 | G4double phi;
|
|---|
| 464 | G4double a, b;
|
|---|
| 465 |
|
|---|
| 466 | do
|
|---|
| 467 | {
|
|---|
| 468 | rand1 = G4UniformRand();
|
|---|
| 469 | rand2 = G4UniformRand();
|
|---|
| 470 | phiProbability=0.;
|
|---|
| 471 | phi = twopi*rand1;
|
|---|
| 472 |
|
|---|
| 473 | a = 2*sinSqrTh;
|
|---|
| 474 | b = energyRate + 1/energyRate;
|
|---|
| 475 |
|
|---|
| 476 | phiProbability = 1 - (a/b)*(std::cos(phi)*std::cos(phi));
|
|---|
| 477 |
|
|---|
| 478 |
|
|---|
| 479 |
|
|---|
| 480 | }
|
|---|
| 481 | while ( rand2 > phiProbability );
|
|---|
| 482 | return phi;
|
|---|
| 483 | }
|
|---|
| 484 |
|
|---|
| 485 |
|
|---|
| 486 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 487 |
|
|---|
| 488 | G4ThreeVector G4LivermorePolarizedComptonModel::SetPerpendicularVector(G4ThreeVector& a)
|
|---|
| 489 | {
|
|---|
| 490 | G4double dx = a.x();
|
|---|
| 491 | G4double dy = a.y();
|
|---|
| 492 | G4double dz = a.z();
|
|---|
| 493 | G4double x = dx < 0.0 ? -dx : dx;
|
|---|
| 494 | G4double y = dy < 0.0 ? -dy : dy;
|
|---|
| 495 | G4double z = dz < 0.0 ? -dz : dz;
|
|---|
| 496 | if (x < y) {
|
|---|
| 497 | return x < z ? G4ThreeVector(-dy,dx,0) : G4ThreeVector(0,-dz,dy);
|
|---|
| 498 | }else{
|
|---|
| 499 | return y < z ? G4ThreeVector(dz,0,-dx) : G4ThreeVector(-dy,dx,0);
|
|---|
| 500 | }
|
|---|
| 501 | }
|
|---|
| 502 |
|
|---|
| 503 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 504 |
|
|---|
| 505 | G4ThreeVector G4LivermorePolarizedComptonModel::GetRandomPolarization(G4ThreeVector& direction0)
|
|---|
| 506 | {
|
|---|
| 507 | G4ThreeVector d0 = direction0.unit();
|
|---|
| 508 | G4ThreeVector a1 = SetPerpendicularVector(d0); //different orthogonal
|
|---|
| 509 | G4ThreeVector a0 = a1.unit(); // unit vector
|
|---|
| 510 |
|
|---|
| 511 | G4double rand1 = G4UniformRand();
|
|---|
| 512 |
|
|---|
| 513 | G4double angle = twopi*rand1; // random polar angle
|
|---|
| 514 | G4ThreeVector b0 = d0.cross(a0); // cross product
|
|---|
| 515 |
|
|---|
| 516 | G4ThreeVector c;
|
|---|
| 517 |
|
|---|
| 518 | c.setX(std::cos(angle)*(a0.x())+std::sin(angle)*b0.x());
|
|---|
| 519 | c.setY(std::cos(angle)*(a0.y())+std::sin(angle)*b0.y());
|
|---|
| 520 | c.setZ(std::cos(angle)*(a0.z())+std::sin(angle)*b0.z());
|
|---|
| 521 |
|
|---|
| 522 | G4ThreeVector c0 = c.unit();
|
|---|
| 523 |
|
|---|
| 524 | return c0;
|
|---|
| 525 |
|
|---|
| 526 | }
|
|---|
| 527 |
|
|---|
| 528 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 529 |
|
|---|
| 530 | G4ThreeVector G4LivermorePolarizedComptonModel::GetPerpendicularPolarization
|
|---|
| 531 | (const G4ThreeVector& gammaDirection, const G4ThreeVector& gammaPolarization) const
|
|---|
| 532 | {
|
|---|
| 533 |
|
|---|
| 534 | //
|
|---|
| 535 | // The polarization of a photon is always perpendicular to its momentum direction.
|
|---|
| 536 | // Therefore this function removes those vector component of gammaPolarization, which
|
|---|
| 537 | // points in direction of gammaDirection
|
|---|
| 538 | //
|
|---|
| 539 | // Mathematically we search the projection of the vector a on the plane E, where n is the
|
|---|
| 540 | // plains normal vector.
|
|---|
| 541 | // The basic equation can be found in each geometry book (e.g. Bronstein):
|
|---|
| 542 | // p = a - (a o n)/(n o n)*n
|
|---|
| 543 |
|
|---|
| 544 | return gammaPolarization - gammaPolarization.dot(gammaDirection)/gammaDirection.dot(gammaDirection) * gammaDirection;
|
|---|
| 545 | }
|
|---|
| 546 |
|
|---|
| 547 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 548 |
|
|---|
| 549 | G4ThreeVector G4LivermorePolarizedComptonModel::SetNewPolarization(G4double epsilon,
|
|---|
| 550 | G4double sinSqrTh,
|
|---|
| 551 | G4double phi,
|
|---|
| 552 | G4double costheta)
|
|---|
| 553 | {
|
|---|
| 554 | G4double rand1;
|
|---|
| 555 | G4double rand2;
|
|---|
| 556 | G4double cosPhi = std::cos(phi);
|
|---|
| 557 | G4double sinPhi = std::sin(phi);
|
|---|
| 558 | G4double sinTheta = std::sqrt(sinSqrTh);
|
|---|
| 559 | G4double cosSqrPhi = cosPhi*cosPhi;
|
|---|
| 560 | // G4double cossqrth = 1.-sinSqrTh;
|
|---|
| 561 | // G4double sinsqrphi = sinPhi*sinPhi;
|
|---|
| 562 | G4double normalisation = std::sqrt(1. - cosSqrPhi*sinSqrTh);
|
|---|
| 563 |
|
|---|
| 564 |
|
|---|
| 565 | // Determination of Theta
|
|---|
| 566 |
|
|---|
| 567 | // ---- MGP ---- Commented out the following 3 lines to avoid compilation
|
|---|
| 568 | // warnings (unused variables)
|
|---|
| 569 | // G4double thetaProbability;
|
|---|
| 570 | G4double theta;
|
|---|
| 571 | // G4double a, b;
|
|---|
| 572 | // G4double cosTheta;
|
|---|
| 573 |
|
|---|
| 574 | /*
|
|---|
| 575 |
|
|---|
| 576 | depaola method
|
|---|
| 577 |
|
|---|
| 578 | do
|
|---|
| 579 | {
|
|---|
| 580 | rand1 = G4UniformRand();
|
|---|
| 581 | rand2 = G4UniformRand();
|
|---|
| 582 | thetaProbability=0.;
|
|---|
| 583 | theta = twopi*rand1;
|
|---|
| 584 | a = 4*normalisation*normalisation;
|
|---|
| 585 | b = (epsilon + 1/epsilon) - 2;
|
|---|
| 586 | thetaProbability = (b + a*std::cos(theta)*std::cos(theta))/(a+b);
|
|---|
| 587 | cosTheta = std::cos(theta);
|
|---|
| 588 | }
|
|---|
| 589 | while ( rand2 > thetaProbability );
|
|---|
| 590 |
|
|---|
| 591 | G4double cosBeta = cosTheta;
|
|---|
| 592 |
|
|---|
| 593 | */
|
|---|
| 594 |
|
|---|
| 595 |
|
|---|
| 596 | // Dan Xu method (IEEE TNS, 52, 1160 (2005))
|
|---|
| 597 |
|
|---|
| 598 | rand1 = G4UniformRand();
|
|---|
| 599 | rand2 = G4UniformRand();
|
|---|
| 600 |
|
|---|
| 601 | if (rand1<(epsilon+1.0/epsilon-2)/(2.0*(epsilon+1.0/epsilon)-4.0*sinSqrTh*cosSqrPhi))
|
|---|
| 602 | {
|
|---|
| 603 | if (rand2<0.5)
|
|---|
| 604 | theta = pi/2.0;
|
|---|
| 605 | else
|
|---|
| 606 | theta = 3.0*pi/2.0;
|
|---|
| 607 | }
|
|---|
| 608 | else
|
|---|
| 609 | {
|
|---|
| 610 | if (rand2<0.5)
|
|---|
| 611 | theta = 0;
|
|---|
| 612 | else
|
|---|
| 613 | theta = pi;
|
|---|
| 614 | }
|
|---|
| 615 | G4double cosBeta = std::cos(theta);
|
|---|
| 616 | G4double sinBeta = std::sqrt(1-cosBeta*cosBeta);
|
|---|
| 617 |
|
|---|
| 618 | G4ThreeVector gammaPolarization1;
|
|---|
| 619 |
|
|---|
| 620 | G4double xParallel = normalisation*cosBeta;
|
|---|
| 621 | G4double yParallel = -(sinSqrTh*cosPhi*sinPhi)*cosBeta/normalisation;
|
|---|
| 622 | G4double zParallel = -(costheta*sinTheta*cosPhi)*cosBeta/normalisation;
|
|---|
| 623 | G4double xPerpendicular = 0.;
|
|---|
| 624 | G4double yPerpendicular = (costheta)*sinBeta/normalisation;
|
|---|
| 625 | G4double zPerpendicular = -(sinTheta*sinPhi)*sinBeta/normalisation;
|
|---|
| 626 |
|
|---|
| 627 | G4double xTotal = (xParallel + xPerpendicular);
|
|---|
| 628 | G4double yTotal = (yParallel + yPerpendicular);
|
|---|
| 629 | G4double zTotal = (zParallel + zPerpendicular);
|
|---|
| 630 |
|
|---|
| 631 | gammaPolarization1.setX(xTotal);
|
|---|
| 632 | gammaPolarization1.setY(yTotal);
|
|---|
| 633 | gammaPolarization1.setZ(zTotal);
|
|---|
| 634 |
|
|---|
| 635 | return gammaPolarization1;
|
|---|
| 636 |
|
|---|
| 637 | }
|
|---|
| 638 |
|
|---|
| 639 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 640 |
|
|---|
| 641 | void G4LivermorePolarizedComptonModel::SystemOfRefChange(G4ThreeVector& direction0,
|
|---|
| 642 | G4ThreeVector& direction1,
|
|---|
| 643 | G4ThreeVector& polarization0,
|
|---|
| 644 | G4ThreeVector& polarization1)
|
|---|
| 645 | {
|
|---|
| 646 | // direction0 is the original photon direction ---> z
|
|---|
| 647 | // polarization0 is the original photon polarization ---> x
|
|---|
| 648 | // need to specify y axis in the real reference frame ---> y
|
|---|
| 649 | G4ThreeVector Axis_Z0 = direction0.unit();
|
|---|
| 650 | G4ThreeVector Axis_X0 = polarization0.unit();
|
|---|
| 651 | G4ThreeVector Axis_Y0 = (Axis_Z0.cross(Axis_X0)).unit(); // to be confirmed;
|
|---|
| 652 |
|
|---|
| 653 | G4double direction_x = direction1.getX();
|
|---|
| 654 | G4double direction_y = direction1.getY();
|
|---|
| 655 | G4double direction_z = direction1.getZ();
|
|---|
| 656 |
|
|---|
| 657 | direction1 = (direction_x*Axis_X0 + direction_y*Axis_Y0 + direction_z*Axis_Z0).unit();
|
|---|
| 658 | G4double polarization_x = polarization1.getX();
|
|---|
| 659 | G4double polarization_y = polarization1.getY();
|
|---|
| 660 | G4double polarization_z = polarization1.getZ();
|
|---|
| 661 |
|
|---|
| 662 | polarization1 = (polarization_x*Axis_X0 + polarization_y*Axis_Y0 + polarization_z*Axis_Z0).unit();
|
|---|
| 663 |
|
|---|
| 664 | }
|
|---|
| 665 |
|
|---|
| 666 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
|
|---|
| 667 |
|
|---|
| 668 | G4double G4LivermorePolarizedComptonModel::GetMeanFreePath(const G4Track& track,
|
|---|
| 669 | G4double,
|
|---|
| 670 | G4ForceCondition*)
|
|---|
| 671 | {
|
|---|
| 672 | const G4DynamicParticle* photon = track.GetDynamicParticle();
|
|---|
| 673 | G4double energy = photon->GetKineticEnergy();
|
|---|
| 674 | const G4MaterialCutsCouple* couple = track.GetMaterialCutsCouple();
|
|---|
| 675 | size_t materialIndex = couple->GetIndex();
|
|---|
| 676 | G4double meanFreePath;
|
|---|
| 677 | if (energy > highEnergyLimit) meanFreePath = meanFreePathTable->FindValue(highEnergyLimit,materialIndex);
|
|---|
| 678 | else if (energy < lowEnergyLimit) meanFreePath = DBL_MAX;
|
|---|
| 679 | else meanFreePath = meanFreePathTable->FindValue(energy,materialIndex);
|
|---|
| 680 | return meanFreePath;
|
|---|
| 681 | }
|
|---|
| 682 |
|
|---|
| 683 |
|
|---|