[819] | 1 | // |
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| 2 | // ******************************************************************** |
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| 3 | // * License and Disclaimer * |
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| 4 | // * * |
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| 5 | // * The Geant4 software is copyright of the Copyright Holders of * |
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| 6 | // * the Geant4 Collaboration. It is provided under the terms and * |
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| 7 | // * conditions of the Geant4 Software License, included in the file * |
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| 8 | // * LICENSE and available at http://cern.ch/geant4/license . These * |
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| 9 | // * include a list of copyright holders. * |
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| 10 | // * * |
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| 11 | // * Neither the authors of this software system, nor their employing * |
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| 12 | // * institutes,nor the agencies providing financial support for this * |
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| 13 | // * work make any representation or warranty, express or implied, * |
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| 14 | // * regarding this software system or assume any liability for its * |
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| 15 | // * use. Please see the license in the file LICENSE and URL above * |
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| 16 | // * for the full disclaimer and the limitation of liability. * |
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| 17 | // * * |
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| 18 | // * This code implementation is the result of the scientific and * |
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| 19 | // * technical work of the GEANT4 collaboration. * |
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| 20 | // * By using, copying, modifying or distributing the software (or * |
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| 21 | // * any work based on the software) you agree to acknowledge its * |
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| 22 | // * use in resulting scientific publications, and indicate your * |
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| 23 | // * acceptance of all terms of the Geant4 Software license. * |
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| 24 | // ******************************************************************** |
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| 25 | // |
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| 26 | // -------------------------------------------------------------------- |
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| 27 | // |
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| 28 | // |
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| 29 | // |
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| 30 | // -------------------------------------------------------------- |
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| 31 | // |
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| 32 | // Author: L.Pandola |
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| 33 | // History: |
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| 34 | // -------- |
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| 35 | // 02 Dec 2002 L.Pandola 1st implementation |
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| 36 | // 12 Feb 2003 MG Pia Migration to "cuts per region" |
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| 37 | // 10 Mar 2003 V.Ivanchenko Remove CutPerMaterial warning |
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| 38 | // 13 Mar 2003 L.Pandola Code "cleaned" |
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| 39 | // 25 Mar 2003 L.Pandola Changed the name of the database file to read |
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| 40 | // 24 Apr 2003 V.Ivanchenko Cut per region mfpt |
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| 41 | // 17 Mar 2004 L.Pandola Removed unnecessary calls to std::pow(a,b) |
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| 42 | // -------------------------------------------------------------- |
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| 43 | |
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| 44 | #include "G4PenelopeGammaConversion.hh" |
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| 45 | |
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| 46 | #include "Randomize.hh" |
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| 47 | #include "G4ParticleDefinition.hh" |
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| 48 | #include "G4Track.hh" |
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| 49 | #include "G4Step.hh" |
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| 50 | #include "G4ForceCondition.hh" |
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| 51 | #include "G4Gamma.hh" |
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| 52 | #include "G4Electron.hh" |
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| 53 | #include "G4DynamicParticle.hh" |
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| 54 | #include "G4VParticleChange.hh" |
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| 55 | #include "G4ThreeVector.hh" |
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| 56 | #include "G4Positron.hh" |
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| 57 | #include "G4IonisParamElm.hh" |
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| 58 | #include "G4Material.hh" |
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| 59 | #include "G4VCrossSectionHandler.hh" |
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| 60 | #include "G4CrossSectionHandler.hh" |
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| 61 | #include "G4VEMDataSet.hh" |
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| 62 | #include "G4VDataSetAlgorithm.hh" |
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| 63 | #include "G4LogLogInterpolation.hh" |
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| 64 | #include "G4VRangeTest.hh" |
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| 65 | #include "G4RangeTest.hh" |
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| 66 | #include "G4MaterialCutsCouple.hh" |
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| 67 | |
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| 68 | |
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| 69 | G4PenelopeGammaConversion::G4PenelopeGammaConversion(const G4String& processName) |
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| 70 | : G4VDiscreteProcess(processName), |
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| 71 | lowEnergyLimit(1.022000*MeV), |
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| 72 | highEnergyLimit(100*GeV), |
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| 73 | intrinsicLowEnergyLimit(1.022000*MeV), |
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| 74 | intrinsicHighEnergyLimit(100*GeV), |
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| 75 | smallEnergy(1.1*MeV) |
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| 76 | |
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| 77 | { |
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| 78 | if (lowEnergyLimit < intrinsicLowEnergyLimit || |
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| 79 | highEnergyLimit > intrinsicHighEnergyLimit) |
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| 80 | { |
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| 81 | G4Exception("G4PenelopeGammaConversion::G4PenelopeGammaConversion - energy limit outside intrinsic process validity range"); |
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| 82 | } |
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| 83 | |
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| 84 | // The following pointer is owned by G4DataHandler |
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| 85 | crossSectionHandler = new G4CrossSectionHandler(); |
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| 86 | // Log log interpolation (default) |
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| 87 | crossSectionHandler->Initialise(0,1.0220*MeV,100.*GeV,400); |
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| 88 | meanFreePathTable = 0; |
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| 89 | rangeTest = new G4RangeTest; |
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| 90 | |
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| 91 | if (verboseLevel > 0) |
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| 92 | { |
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| 93 | G4cout << GetProcessName() << " is created " << G4endl |
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| 94 | << "Energy range: " |
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| 95 | << lowEnergyLimit / MeV << " MeV - " |
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| 96 | << highEnergyLimit / GeV << " GeV" |
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| 97 | << G4endl; |
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| 98 | } |
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[1055] | 99 | |
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| 100 | G4cout << G4endl; |
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| 101 | G4cout << "*******************************************************************************" << G4endl; |
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| 102 | G4cout << "*******************************************************************************" << G4endl; |
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| 103 | G4cout << " The class G4PenelopeGammaConversion is NOT SUPPORTED ANYMORE. " << G4endl; |
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| 104 | G4cout << " It will be REMOVED with the next major release of Geant4. " << G4endl; |
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| 105 | G4cout << " Please consult: https://twiki.cern.ch/twiki/bin/view/Geant4/LoweProcesses" << G4endl; |
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| 106 | G4cout << "*******************************************************************************" << G4endl; |
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| 107 | G4cout << "*******************************************************************************" << G4endl; |
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| 108 | G4cout << G4endl; |
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[819] | 109 | } |
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| 110 | |
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| 111 | G4PenelopeGammaConversion::~G4PenelopeGammaConversion() |
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| 112 | { |
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| 113 | delete meanFreePathTable; |
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| 114 | delete crossSectionHandler; |
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| 115 | delete rangeTest; |
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| 116 | } |
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| 117 | |
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| 118 | void G4PenelopeGammaConversion::BuildPhysicsTable(const G4ParticleDefinition& ) |
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| 119 | { |
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| 120 | |
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| 121 | crossSectionHandler->Clear(); |
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| 122 | G4String crossSectionFile = "penelope/pp-cs-pen-"; |
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| 123 | crossSectionHandler->LoadData(crossSectionFile); |
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| 124 | delete meanFreePathTable; |
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| 125 | meanFreePathTable = crossSectionHandler->BuildMeanFreePathForMaterials(); |
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| 126 | } |
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| 127 | |
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| 128 | G4VParticleChange* G4PenelopeGammaConversion::PostStepDoIt(const G4Track& aTrack, |
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| 129 | const G4Step& aStep) |
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| 130 | { |
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| 131 | aParticleChange.Initialize(aTrack); |
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| 132 | |
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| 133 | const G4MaterialCutsCouple* couple = aTrack.GetMaterialCutsCouple(); |
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| 134 | |
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| 135 | const G4DynamicParticle* incidentPhoton = aTrack.GetDynamicParticle(); |
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| 136 | G4double photonEnergy = incidentPhoton->GetKineticEnergy(); |
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| 137 | G4ParticleMomentum photonDirection = incidentPhoton->GetMomentumDirection(); |
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| 138 | |
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| 139 | G4double eps ; |
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| 140 | G4double eki = electron_mass_c2 / photonEnergy ; |
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| 141 | |
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| 142 | // Do it fast if photon energy < 1.1 MeV |
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| 143 | if (photonEnergy < smallEnergy ) |
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| 144 | { |
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| 145 | eps = eki + (1-2*eki) * G4UniformRand(); |
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| 146 | } |
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| 147 | else |
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| 148 | { |
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| 149 | // Select randomly one element in the current material |
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| 150 | const G4Element* element = crossSectionHandler->SelectRandomElement(couple,photonEnergy); |
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| 151 | |
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| 152 | if (element == 0) |
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| 153 | { |
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| 154 | G4cout << "G4PenelopeGammaConversion::PostStepDoIt - element = 0" << G4endl; |
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| 155 | } |
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| 156 | G4IonisParamElm* ionisation = element->GetIonisation(); |
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| 157 | if (ionisation == 0) |
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| 158 | { |
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| 159 | G4cout << "G4PenelopeGammaConversion::PostStepDoIt - ionisation = 0" << G4endl; |
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| 160 | } |
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| 161 | |
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| 162 | //Low energy and Coulomb corrections |
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| 163 | G4double Z=ionisation->GetZ(); |
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| 164 | G4double ZAlpha = Z*fine_structure_const; |
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| 165 | G4double ScreenRadius = GetScreeningRadius(Z); |
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| 166 | G4double funct1=0,g0=0; |
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| 167 | G4double g1min=0,g2min=0; |
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| 168 | funct1 = 4.0*std::log(ScreenRadius); |
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| 169 | g0 = funct1-4*CoulombCorrection(ZAlpha)+LowEnergyCorrection(ZAlpha,eki); |
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| 170 | G4double bmin = 2*eki*ScreenRadius; |
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| 171 | g1min=g0+ScreenFunction(bmin,1); |
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| 172 | g2min=g0+ScreenFunction(bmin,2); |
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| 173 | G4double xr,a1,p1; |
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| 174 | xr=0.5-eki; |
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| 175 | a1=(2.0/3.0)*g1min*xr*xr; |
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| 176 | p1=a1/(a1+g2min); |
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| 177 | |
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| 178 | //Random sampling of eps |
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| 179 | G4double rand1,rand2,rand3,b; |
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| 180 | G4double g1; |
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| 181 | |
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| 182 | do{ |
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| 183 | rand1 = G4UniformRand(); |
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| 184 | if (rand1 < p1) { |
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| 185 | rand2 = 2.0*G4UniformRand()-1.0; |
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| 186 | if (rand2 < 0) { |
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| 187 | eps = 0.5 - xr*std::pow(std::abs(rand2),(1./3.)); |
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| 188 | } |
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| 189 | else |
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| 190 | { |
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| 191 | eps = 0.5 + xr*std::pow(rand2,(1./3.)); |
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| 192 | } |
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| 193 | b = (eki*ScreenRadius)/(2*eps*(1.0-eps)); |
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| 194 | g1 = g0+ScreenFunction(b,1); |
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| 195 | if (g1 < 0) g1=0; |
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| 196 | rand3 = G4UniformRand()*g1min; |
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| 197 | } |
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| 198 | else |
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| 199 | { |
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| 200 | eps = eki+2.0*xr*G4UniformRand(); |
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| 201 | b = (eki*ScreenRadius)/(2*eps*(1.0-eps)); |
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| 202 | g1 = g0+ScreenFunction(b,2); |
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| 203 | if (g1 < 0) g1=0; |
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| 204 | rand3 = G4UniformRand()*g2min; |
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| 205 | } |
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| 206 | } while (rand3>g1); |
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| 207 | } //End of eps sampling |
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| 208 | |
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| 209 | G4double electronTotEnergy; |
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| 210 | G4double positronTotEnergy; |
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| 211 | |
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| 212 | electronTotEnergy = eps*photonEnergy; |
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| 213 | positronTotEnergy = (1.0-eps)*photonEnergy; |
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| 214 | |
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| 215 | // Scattered electron (positron) angles. ( Z - axis along the parent photon) |
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| 216 | |
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| 217 | //electron kinematics |
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| 218 | G4double costheta_el,costheta_po; |
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| 219 | G4double phi_el,phi_po; |
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| 220 | G4double electronKineEnergy = std::max(0.,electronTotEnergy - electron_mass_c2) ; |
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| 221 | costheta_el = G4UniformRand()*2.0-1.0; |
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| 222 | G4double kk = std::sqrt(electronKineEnergy*(electronKineEnergy+2.*electron_mass_c2)); |
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| 223 | costheta_el = (costheta_el*electronTotEnergy+kk)/(electronTotEnergy+costheta_el*kk); |
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| 224 | phi_el = twopi * G4UniformRand() ; |
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| 225 | G4double dirX_el = std::sqrt(1.-costheta_el*costheta_el) * std::cos(phi_el); |
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| 226 | G4double dirY_el = std::sqrt(1.-costheta_el*costheta_el) * std::sin(phi_el); |
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| 227 | G4double dirZ_el = costheta_el; |
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| 228 | |
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| 229 | //positron kinematics |
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| 230 | G4double positronKineEnergy = std::max(0.,positronTotEnergy - electron_mass_c2) ; |
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| 231 | costheta_po = G4UniformRand()*2.0-1.0; |
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| 232 | kk = std::sqrt(positronKineEnergy*(positronKineEnergy+2.*electron_mass_c2)); |
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| 233 | costheta_po = (costheta_po*positronTotEnergy+kk)/(positronTotEnergy+costheta_po*kk); |
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| 234 | phi_po = twopi * G4UniformRand() ; |
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| 235 | G4double dirX_po = std::sqrt(1.-costheta_po*costheta_po) * std::cos(phi_po); |
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| 236 | G4double dirY_po = std::sqrt(1.-costheta_po*costheta_po) * std::sin(phi_po); |
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| 237 | G4double dirZ_po = costheta_po; |
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| 238 | |
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| 239 | // Kinematics of the created pair: |
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| 240 | // the electron and positron are assumed to have a symetric angular |
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| 241 | // distribution with respect to the Z axis along the parent photon |
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| 242 | |
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| 243 | G4double localEnergyDeposit = 0. ; |
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| 244 | |
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| 245 | aParticleChange.SetNumberOfSecondaries(2) ; |
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| 246 | |
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| 247 | |
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| 248 | // Generate the electron only if with large enough range w.r.t. cuts and safety |
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| 249 | |
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| 250 | G4double safety = aStep.GetPostStepPoint()->GetSafety(); |
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| 251 | |
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| 252 | if (rangeTest->Escape(G4Electron::Electron(),couple,electronKineEnergy,safety)) |
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| 253 | { |
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| 254 | G4ThreeVector electronDirection ( dirX_el, dirY_el, dirZ_el); |
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| 255 | electronDirection.rotateUz(photonDirection); |
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| 256 | G4DynamicParticle* particle1 = new G4DynamicParticle (G4Electron::Electron(), |
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| 257 | electronDirection, |
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| 258 | electronKineEnergy); |
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| 259 | aParticleChange.AddSecondary(particle1) ; |
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| 260 | } |
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| 261 | else |
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| 262 | { |
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| 263 | localEnergyDeposit += electronKineEnergy ; |
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| 264 | } |
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| 265 | |
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| 266 | |
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| 267 | if (! (rangeTest->Escape(G4Positron::Positron(),couple,positronKineEnergy,safety))) |
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| 268 | { |
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| 269 | localEnergyDeposit += positronKineEnergy ; |
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| 270 | positronKineEnergy = 0. ; |
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| 271 | } |
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| 272 | G4ThreeVector positronDirection(dirX_po,dirY_po,dirZ_po); |
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| 273 | positronDirection.rotateUz(photonDirection); |
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| 274 | |
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| 275 | // Create G4DynamicParticle object for the particle2 |
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| 276 | G4DynamicParticle* particle2 = new G4DynamicParticle(G4Positron::Positron(), |
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| 277 | positronDirection, positronKineEnergy); |
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| 278 | aParticleChange.AddSecondary(particle2) ; |
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| 279 | |
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| 280 | aParticleChange.ProposeLocalEnergyDeposit(localEnergyDeposit) ; |
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| 281 | |
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| 282 | // Kill the incident photon |
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| 283 | aParticleChange.ProposeMomentumDirection(0.,0.,0.) ; |
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| 284 | aParticleChange.ProposeEnergy(0.) ; |
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| 285 | aParticleChange.ProposeTrackStatus(fStopAndKill) ; |
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| 286 | |
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| 287 | // Reset NbOfInteractionLengthLeft and return aParticleChange |
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| 288 | return G4VDiscreteProcess::PostStepDoIt(aTrack,aStep); |
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| 289 | } |
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| 290 | |
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| 291 | G4bool G4PenelopeGammaConversion::IsApplicable(const G4ParticleDefinition& particle) |
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| 292 | { |
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| 293 | return ( &particle == G4Gamma::Gamma() ); |
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| 294 | } |
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| 295 | |
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| 296 | G4double G4PenelopeGammaConversion::GetMeanFreePath(const G4Track& track, |
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| 297 | G4double, // previousStepSize |
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| 298 | G4ForceCondition*) |
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| 299 | { |
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| 300 | const G4DynamicParticle* photon = track.GetDynamicParticle(); |
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| 301 | G4double energy = photon->GetKineticEnergy(); |
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| 302 | const G4MaterialCutsCouple* couple = track.GetMaterialCutsCouple(); |
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| 303 | size_t materialIndex = couple->GetIndex(); |
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| 304 | |
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| 305 | G4double meanFreePath; |
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| 306 | if (energy > highEnergyLimit) meanFreePath = meanFreePathTable->FindValue(highEnergyLimit,materialIndex); |
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| 307 | else if (energy < lowEnergyLimit) meanFreePath = DBL_MAX; |
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| 308 | else meanFreePath = meanFreePathTable->FindValue(energy,materialIndex); |
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| 309 | return meanFreePath; |
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| 310 | } |
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| 311 | |
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| 312 | G4double G4PenelopeGammaConversion::ScreenFunction(G4double b,G4int icase) |
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| 313 | { |
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| 314 | G4double bsquare=b*b; |
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| 315 | G4double a0,f1,f2,g1,g2; |
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| 316 | f1=2.0-2*std::log(1+bsquare); |
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| 317 | f2=f1-(2.0/3.0); |
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| 318 | if (b < 1.0e-10) |
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| 319 | { |
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| 320 | f1=f1-twopi*b; |
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| 321 | } |
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| 322 | else |
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| 323 | { |
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| 324 | a0 = 4*b*std::atan(1.0/b); |
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| 325 | f1 = f1 - a0; |
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| 326 | f2 = f2+2*bsquare*(4.0-a0-3*std::log((1+bsquare)/bsquare)); |
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| 327 | } |
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| 328 | g1=0.5*(3*f1-f2); |
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| 329 | g2=0.25*(3*f1+f2); |
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| 330 | if (icase==1) { |
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| 331 | return g1; |
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| 332 | } |
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| 333 | else |
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| 334 | { |
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| 335 | return g2; |
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| 336 | } |
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| 337 | } |
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| 338 | |
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| 339 | G4double G4PenelopeGammaConversion::CoulombCorrection(G4double a) |
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| 340 | { |
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| 341 | G4double fc=0; |
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| 342 | G4double b[7] = {0.202059,-0.03693,0.00835,-0.00201,0.00049,-0.00012,0.00003}; |
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| 343 | G4double aSquared = a*a; |
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| 344 | G4double aFourth = aSquared*aSquared; |
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| 345 | G4double aEighth = aFourth*aFourth; |
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| 346 | |
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| 347 | fc = ((1.0/(1.0+a*a))+b[0]+b[1]*aSquared+b[2]*aFourth+b[3]*(aSquared*aFourth)+ |
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| 348 | b[4]*aEighth+b[5]*(aEighth*aSquared)+b[6]*(aEighth*aFourth)); |
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| 349 | fc=aSquared*fc; |
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| 350 | return fc; |
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| 351 | } |
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| 352 | |
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| 353 | G4double G4PenelopeGammaConversion::LowEnergyCorrection(G4double a,G4double eki) |
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| 354 | { |
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| 355 | G4double f0=0,t=0; |
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| 356 | G4double b[12] = {-1.744,-12.10,11.18,8.523,73.26,-41.41,-13.52,-121.1,94.41,8.946,62.05,-63.41}; |
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| 357 | t=std::sqrt(2.0*eki); |
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| 358 | G4double tSq = t*t; |
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| 359 | f0=(b[0]+b[1]*a+b[2]*a*a)*t+(b[3]+b[4]*a+b[5]*a*a)*(tSq)+(b[6]+b[7]*a+b[8]*a*a)*(tSq*t)+ |
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| 360 | (b[9]+b[10]*a+b[11]*a*a)*(tSq*tSq); |
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| 361 | return f0; |
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| 362 | } |
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| 363 | |
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| 364 | G4double G4PenelopeGammaConversion::GetScreeningRadius(G4double Z) |
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| 365 | { |
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| 366 | char* path = getenv("G4LEDATA"); |
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| 367 | if (!path) |
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| 368 | { |
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| 369 | G4String excep = "G4PenelopeGammaConversion - G4LEDATA environment variable not set!"; |
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| 370 | G4Exception(excep); |
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| 371 | } |
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| 372 | G4String pathString(path); |
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| 373 | G4String pathFile = pathString + "/penelope/pp-pen.dat"; |
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| 374 | std::ifstream file(pathFile); |
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| 375 | std::filebuf* lsdp = file.rdbuf(); |
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| 376 | |
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| 377 | if (!(lsdp->is_open())) |
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| 378 | { |
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| 379 | G4String excep = "G4PenelopeGammaConversion - data file " + pathFile + "not found!"; |
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| 380 | G4Exception(excep); |
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| 381 | } |
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| 382 | G4int k; |
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| 383 | G4double a1,a2; |
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| 384 | while(!file.eof()) { |
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| 385 | file >> k >> a1 >> a2; |
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| 386 | if ((G4double) k == Z) |
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| 387 | { |
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| 388 | return a1; |
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| 389 | } |
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| 390 | } |
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| 391 | G4String excep = "G4PenelopeGammaConversion - Screening Radius for not found in the data file"; |
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| 392 | G4Exception(excep); |
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| 393 | return 0; |
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| 394 | } |
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