[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 | // $Id: G4CoulombScatteringModel.cc,v 1.29 2007/11/09 11:45:45 vnivanch Exp $ |
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| 27 | // GEANT4 tag $Name: geant4-09-01-patch-02 $ |
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| 28 | // |
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| 29 | // ------------------------------------------------------------------- |
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| 30 | // |
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| 31 | // GEANT4 Class file |
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| 32 | // |
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| 33 | // |
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| 34 | // File name: G4CoulombScatteringModel |
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| 35 | // |
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| 36 | // Author: Vladimir Ivanchenko |
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| 37 | // |
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| 38 | // Creation date: 22.08.2005 |
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| 39 | // |
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| 40 | // Modifications: |
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| 41 | // 01.08.06 V.Ivanchenko extend upper limit of table to TeV and review the |
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| 42 | // logic of building - only elements from G4ElementTable |
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| 43 | // 08.08.06 V.Ivanchenko build internal table in ekin scale, introduce faclim |
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| 44 | // 19.10.06 V.Ivanchenko use inheritance from G4eCoulombScatteringModel |
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| 45 | // 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e- |
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| 46 | // |
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| 47 | // Class Description: |
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| 48 | // |
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| 49 | // ------------------------------------------------------------------- |
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| 50 | // |
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| 51 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 52 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 53 | |
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| 54 | #include "G4CoulombScatteringModel.hh" |
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| 55 | #include "Randomize.hh" |
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| 56 | #include "G4ParticleChangeForGamma.hh" |
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| 57 | #include "G4NistManager.hh" |
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| 58 | #include "G4ParticleTable.hh" |
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| 59 | #include "G4IonTable.hh" |
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| 60 | #include "G4Proton.hh" |
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| 61 | |
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| 62 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 63 | |
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| 64 | using namespace std; |
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| 65 | |
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| 66 | G4CoulombScatteringModel::G4CoulombScatteringModel( |
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| 67 | G4double thetaMin, G4double thetaMax, G4bool build, |
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| 68 | G4double tlim, const G4String& nam) |
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| 69 | : G4eCoulombScatteringModel(thetaMin,thetaMax,build,tlim,nam) |
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| 70 | { |
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| 71 | theMatManager = G4NistManager::Instance(); |
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| 72 | theParticleTable = G4ParticleTable::GetParticleTable(); |
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| 73 | } |
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| 74 | |
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| 75 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 76 | |
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| 77 | G4CoulombScatteringModel::~G4CoulombScatteringModel() |
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| 78 | {} |
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| 79 | |
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| 80 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 81 | |
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| 82 | G4double G4CoulombScatteringModel::ComputeCrossSectionPerAtom( |
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| 83 | const G4ParticleDefinition* p, |
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| 84 | G4double kinEnergy, |
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| 85 | G4double Z, |
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| 86 | G4double A, |
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| 87 | G4double cutEnergy, |
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| 88 | G4double) |
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| 89 | { |
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| 90 | if(p == particle && kinEnergy == tkin && Z == targetZ && |
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| 91 | A == targetA && cutEnergy == ecut) return nucXSection; |
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| 92 | |
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| 93 | // Lab system |
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| 94 | G4double ekin = std::max(keV, kinEnergy); |
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| 95 | nucXSection = ComputeElectronXSectionPerAtom(p,ekin,Z,A,cutEnergy); |
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| 96 | |
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| 97 | // CM system |
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| 98 | G4int iz = G4int(Z); |
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| 99 | G4double m1 = theMatManager->GetAtomicMassAmu(iz)*amu_c2; |
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| 100 | G4double etot = tkin + mass; |
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| 101 | G4double ptot = sqrt(mom2); |
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| 102 | G4double bet = ptot/(etot + m1); |
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| 103 | G4double gam = 1.0/sqrt((1.0 - bet)*(1.0 + bet)); |
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| 104 | G4double momCM= gam*(ptot - bet*etot); |
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| 105 | |
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| 106 | // G4cout << "ptot= " << ptot << " etot= " << etot << " beta= " |
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| 107 | // << bet << " gam= " << gam << " Z= " << Z << " A= " << A << G4endl; |
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| 108 | // G4cout << " CM. mom= " << momCM << " m= " << m |
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| 109 | // << " m1= " << m1 << " iz= " << iz <<G4endl; |
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| 110 | |
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| 111 | G4double momCM2 = momCM*momCM; |
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| 112 | cosTetMaxNuc = std::max(cosThetaMax, 1.0 - 0.5*q2Limit/momCM2); |
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| 113 | if(1.5 > targetA && p == theProton && cosTetMaxNuc < 0.0) cosTetMaxNuc = 0.0; |
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| 114 | //G4cout << " ctmax= " << cosTetMaxNuc |
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| 115 | //<< " ctmin= " << cosThetaMin << G4endl; |
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| 116 | |
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| 117 | // Cross section in CM system |
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| 118 | if(cosTetMaxNuc < cosThetaMin) { |
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| 119 | G4double effmass = mass*m1/(mass + m1); |
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| 120 | G4double x1 = 1.0 - cosThetaMin; |
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| 121 | G4double x2 = 1.0 - cosTetMaxNuc; |
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| 122 | G4double z1 = x1 + screenZ; |
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| 123 | G4double z2 = x2 + screenZ; |
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| 124 | G4double d = 1.0/formfactA; |
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| 125 | G4double zn1= x1 + d; |
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| 126 | G4double zn2= x2 + d; |
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| 127 | nucXSection += coeff*Z*Z*chargeSquare*(1.0 + effmass*effmass/momCM2) |
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| 128 | *(1./z1 - 1./z2 + 1./zn1 - 1./zn2 + |
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| 129 | 2.0*formfactA*std::log(z1*zn2/(z2*zn1)))/momCM2; |
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| 130 | //G4cout << "XS: x1= " << x1 << " x2= " << x2 |
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| 131 | //<< " cross= " << cross << G4endl; |
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| 132 | //G4cout << "momCM2= " << momCM2 << " invbeta2= " << invbeta2 |
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| 133 | // << " coeff= " << coeff << G4endl; |
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| 134 | } |
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| 135 | if(nucXSection < 0.0) nucXSection = 0.0; |
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| 136 | return nucXSection; |
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| 137 | } |
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| 138 | |
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| 139 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 140 | |
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| 141 | G4double G4CoulombScatteringModel::SelectIsotope(const G4Element* elm) |
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| 142 | { |
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| 143 | G4double N = elm->GetN(); |
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| 144 | G4int ni = elm->GetNumberOfIsotopes(); |
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| 145 | if(ni > 0) { |
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| 146 | G4double* ab = elm->GetRelativeAbundanceVector(); |
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| 147 | G4double x = G4UniformRand(); |
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| 148 | G4int idx; |
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| 149 | for(idx=0; idx<ni; idx++) { |
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| 150 | x -= ab[idx]; |
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| 151 | if (x <= 0.0) break; |
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| 152 | } |
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| 153 | if(idx >= ni) { |
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| 154 | G4cout << "G4CoulombScatteringModel::SelectIsotope WARNING: " |
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| 155 | << "abandance vector for" |
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| 156 | << elm->GetName() << " is not normalised to unit" << G4endl; |
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| 157 | } else { |
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| 158 | N = G4double(elm->GetIsotope(idx)->GetN()); |
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| 159 | } |
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| 160 | } |
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| 161 | return N; |
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| 162 | } |
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| 163 | |
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| 164 | //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.... |
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| 165 | |
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| 166 | void G4CoulombScatteringModel::SampleSecondaries( |
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| 167 | std::vector<G4DynamicParticle*>* fvect, |
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| 168 | const G4MaterialCutsCouple* couple, |
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| 169 | const G4DynamicParticle* dp, |
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| 170 | G4double cutEnergy, |
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| 171 | G4double maxEnergy) |
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| 172 | { |
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| 173 | const G4Material* aMaterial = couple->GetMaterial(); |
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| 174 | const G4ParticleDefinition* p = dp->GetDefinition(); |
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| 175 | G4double kinEnergy = dp->GetKineticEnergy(); |
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| 176 | |
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| 177 | // Select isotope and setup |
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| 178 | SetupParticle(p); |
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| 179 | const G4Element* elm = |
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| 180 | SelectRandomAtom(aMaterial,p,kinEnergy,cutEnergy,maxEnergy); |
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| 181 | G4double Z = elm->GetZ(); |
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| 182 | G4double A = SelectIsotope(elm); |
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| 183 | G4int iz = G4int(Z); |
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| 184 | G4int ia = G4int(A + 0.5); |
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| 185 | |
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| 186 | G4double cross = |
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| 187 | ComputeCrossSectionPerAtom(p,kinEnergy,Z,A,cutEnergy,maxEnergy); |
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| 188 | |
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| 189 | G4double costm = cosTetMaxNuc; |
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| 190 | G4double formf = formfactA; |
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| 191 | if(G4UniformRand()*cross < elecXSection) { |
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| 192 | costm = cosTetMaxElec; |
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| 193 | formf = 0.0; |
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| 194 | } |
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| 195 | |
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| 196 | // G4cout << "SampleSec: Ekin= " << kinEnergy << " m1= " << m1 |
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| 197 | // << " Z= "<< Z << " A= " <<A<< G4endl; |
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| 198 | |
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| 199 | if(costm >= cosThetaMin) return; |
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| 200 | |
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| 201 | // kinematics in CM system |
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| 202 | G4double m1 = theParticleTable->GetIonTable()->GetNucleusMass(iz, ia); |
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| 203 | G4double etot = kinEnergy + mass; |
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| 204 | G4double ptot = sqrt(mom2); |
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| 205 | G4double bet = ptot/(etot + m1); |
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| 206 | G4double gam = 1.0/sqrt((1.0 - bet)*(1.0 + bet)); |
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| 207 | G4double pCM = gam*(ptot - bet*etot); |
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| 208 | G4double eCM = gam*(etot - bet*ptot); |
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| 209 | |
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| 210 | G4double x1 = 1. - cosThetaMin + screenZ; |
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| 211 | G4double x2 = 1. - costm; |
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| 212 | G4double x3 = cosThetaMin - costm; |
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| 213 | |
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| 214 | G4double grej, z, z1; |
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| 215 | do { |
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| 216 | z = G4UniformRand()*x3; |
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| 217 | z1 = (x1*x2 - screenZ*z)/(x1 + z); |
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| 218 | if(z1 < 0.0) z1 = 0.0; |
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| 219 | else if(z1 > 2.0) z1 = 2.0; |
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| 220 | grej = 1.0/(1.0 + formf*z1); |
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| 221 | } while ( G4UniformRand() > grej*grej ); |
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| 222 | |
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| 223 | G4double cost = 1.0 - z1; |
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| 224 | G4double sint= sqrt(z1*(2.0 - z1)); |
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| 225 | |
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| 226 | G4double phi = twopi * G4UniformRand(); |
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| 227 | |
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| 228 | // projectile after scattering |
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| 229 | G4double pzCM = pCM*cost; |
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| 230 | G4ThreeVector v1(pCM*cos(phi)*sint,pCM*sin(phi)*sint,gam*(pzCM + bet*eCM)); |
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| 231 | G4ThreeVector dir = dp->GetMomentumDirection(); |
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| 232 | G4ThreeVector newDirection = v1.unit(); |
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| 233 | newDirection.rotateUz(dir); |
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| 234 | fParticleChange->ProposeMomentumDirection(newDirection); |
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| 235 | G4double elab = gam*(eCM + bet*pzCM); |
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| 236 | G4double ekin = elab - mass; |
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| 237 | if(ekin < 0.0) ekin = 0.0; |
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| 238 | G4double plab = sqrt(ekin*(ekin + 2.0*mass)); |
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| 239 | fParticleChange->SetProposedKineticEnergy(ekin); |
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| 240 | |
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| 241 | // recoil |
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| 242 | G4double erec = kinEnergy - ekin; |
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| 243 | if(erec > Z*aMaterial->GetIonisation()->GetMeanExcitationEnergy()) { |
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| 244 | G4ParticleDefinition* ion = theParticleTable->FindIon(iz, ia, 0, iz); |
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| 245 | G4ThreeVector p2 = (ptot*dir - plab*newDirection).unit(); |
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| 246 | G4DynamicParticle* newdp = new G4DynamicParticle(ion, p2, erec); |
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| 247 | fvect->push_back(newdp); |
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| 248 | } else if(erec > 0.0) { |
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| 249 | fParticleChange->ProposeLocalEnergyDeposit(erec); |
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| 250 | fParticleChange->ProposeNonIonizingEnergyDeposit(erec); |
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| 251 | } |
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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 | |
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