| 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 | // GEANT4 tag $Name: hadr-cross-V09-03-12 $ |
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| 28 | // |
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| 29 | // |
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| 30 | // GEANT4 physics class: G4ElectroNuclearCrossSection -- header file |
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| 31 | // M.V. Kossov, ITEP(Moscow), 24-OCT-01 |
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| 32 | // The last update: M.V. Kossov, CERN/ITEP (Moscow) 25-Sept-03 |
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| 33 | // |
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| 34 | |
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| 35 | #ifndef G4ElectroNuclearCrossSection_h |
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| 36 | #define G4ElectroNuclearCrossSection_h 1 |
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| 37 | |
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| 38 | #include "G4VCrossSectionDataSet.hh" |
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| 39 | #include "G4DynamicParticle.hh" |
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| 40 | #include "G4Element.hh" |
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| 41 | #include "G4ParticleTable.hh" |
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| 42 | #include "G4NucleiProperties.hh" |
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| 43 | #include <vector> |
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| 44 | #include "Randomize.hh" |
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| 45 | #include "G4Electron.hh" |
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| 46 | #include "G4Positron.hh" |
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| 47 | |
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| 48 | class G4ElectroNuclearCrossSection : public G4VCrossSectionDataSet |
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| 49 | { |
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| 50 | public: |
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| 51 | |
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| 52 | G4ElectroNuclearCrossSection(); |
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| 53 | virtual ~G4ElectroNuclearCrossSection(); |
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| 54 | |
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| 55 | G4bool IsApplicable(const G4DynamicParticle* aParticle, const G4Element* ) |
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| 56 | { |
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| 57 | return IsIsoApplicable(aParticle, 0, 0); |
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| 58 | } |
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| 59 | |
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| 60 | G4bool IsIsoApplicable(const G4DynamicParticle* aParticle, |
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| 61 | G4int /*ZZ*/, G4int /*AA*/) |
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| 62 | { |
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| 63 | G4bool result = false; |
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| 64 | if (aParticle->GetDefinition() == G4Electron::ElectronDefinition()) |
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| 65 | result = true; |
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| 66 | if (aParticle->GetDefinition() == G4Positron::PositronDefinition()) |
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| 67 | result = true; |
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| 68 | return result; |
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| 69 | } |
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| 70 | |
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| 71 | |
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| 72 | G4double GetCrossSection(const G4DynamicParticle* aParticle, |
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| 73 | const G4Element* anElement, G4double T=0.); |
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| 74 | |
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| 75 | G4double GetZandACrossSection(const G4DynamicParticle* aParticle, |
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| 76 | G4int ZZ, G4int AA, G4double T=0.); |
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| 77 | |
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| 78 | G4double GetEquivalentPhotonEnergy(); |
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| 79 | |
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| 80 | G4double GetVirtualFactor(G4double nu, G4double Q2); |
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| 81 | |
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| 82 | G4double GetEquivalentPhotonQ2(G4double nu); |
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| 83 | |
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| 84 | void BuildPhysicsTable(const G4ParticleDefinition&) {} |
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| 85 | |
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| 86 | void DumpPhysicsTable(const G4ParticleDefinition&) {} |
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| 87 | |
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| 88 | private: |
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| 89 | G4int GetFunctions(G4double a, G4double* x, G4double* y, G4double* z); |
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| 90 | |
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| 91 | G4double ThresholdEnergy(G4int Z, G4int N); |
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| 92 | G4double HighEnergyJ1(G4double lE); |
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| 93 | G4double HighEnergyJ2(G4double lE); |
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| 94 | G4double HighEnergyJ3(G4double lE); |
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| 95 | G4double SolveTheEquation(G4double f); |
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| 96 | G4double Fun(G4double x); |
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| 97 | G4double DFun(G4double x); |
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| 98 | |
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| 99 | // Body |
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| 100 | private: |
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| 101 | static G4int lastN; // The last N of calculated nucleus |
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| 102 | static G4int lastZ; // The last Z of calculated nucleus |
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| 103 | static G4int lastF; // Last used in the cross section TheFirstBin |
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| 104 | static G4double* lastJ1; // Pointer to the last array of the J1 function |
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| 105 | static G4double* lastJ2; // Pointer to the last array of the J2 function |
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| 106 | static G4double* lastJ3; // Pointer to the last array of the J3 function |
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| 107 | static G4int lastL; // Last used in the cross section TheLastBin |
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| 108 | static G4double lastE; // Last used in the cross section Energy |
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| 109 | static G4double lastTH; // Last value of the Energy Threshold |
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| 110 | static G4double lastSig; // Last value of the Cross Section |
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| 111 | static G4double lastG; // Last value of gamma=lnE-ln(me) |
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| 112 | static G4double lastH; // Last value of the High energy A-dependence |
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| 113 | |
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| 114 | // Vector of pointers to the J1 tabulated functions |
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| 115 | static std::vector <G4double*> J1; |
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| 116 | |
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| 117 | // Vector of pointers to the J2 tabulated functions |
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| 118 | static std::vector <G4double*> J2; |
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| 119 | |
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| 120 | // Vector of pointers to the J3 tabulated functions |
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| 121 | static std::vector <G4double*> J3; |
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| 122 | }; |
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| 123 | |
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| 124 | |
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| 125 | inline G4double |
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| 126 | G4ElectroNuclearCrossSection::DFun(G4double x) |
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| 127 | { |
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| 128 | // Parametrization of the PhotoNucCS |
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| 129 | static const G4double shd=1.0734; // HE PomShadowing(D) |
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| 130 | static const G4double poc=0.0375; // HE Pomeron coefficient |
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| 131 | static const G4double pos=16.5; // HE Pomeron shift |
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| 132 | static const G4double reg=.11; // HE Reggeon slope |
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| 133 | static const G4double mel=0.5109989; // Mass of an electron in MeV |
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| 134 | static const G4double lmel=std::log(mel); // Log of an electron mass |
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| 135 | G4double y=std::exp(x-lastG-lmel); // y for the x |
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| 136 | G4double flux=lastG*(2.-y*(2.-y))-1.; // flux factor |
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| 137 | return (poc*(x-pos)+shd*std::exp(-reg*x))*flux; |
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| 138 | } |
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| 139 | |
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| 140 | |
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| 141 | inline G4double |
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| 142 | G4ElectroNuclearCrossSection::Fun(G4double x) |
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| 143 | { |
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| 144 | // Integrated PhoNuc cross section |
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| 145 | G4double dlg1=lastG+lastG-1.; |
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| 146 | G4double lgoe=lastG/lastE; |
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| 147 | G4double HE2=HighEnergyJ2(x); |
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| 148 | return dlg1*HighEnergyJ1(x)-lgoe*(HE2+HE2-HighEnergyJ3(x)/lastE); |
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| 149 | } |
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| 150 | |
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| 151 | |
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| 152 | inline G4double |
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| 153 | G4ElectroNuclearCrossSection::HighEnergyJ1(G4double lEn) |
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| 154 | { |
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| 155 | static const G4double le=std::log(50000.); // std::log(E0) |
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| 156 | static const G4double le2=le*le; // std::log(E0)^2 |
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| 157 | static const G4double a=.0375; // a |
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| 158 | static const G4double ha=a*.5; // a/2 |
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| 159 | static const G4double ab=a*16.5; // a*b |
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| 160 | static const G4double d=0.11; // d |
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| 161 | static const G4double cd=1.0734/d; // c/d |
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| 162 | static const G4double ele=std::exp(-d*le); // E0^(-d) |
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| 163 | return ha*(lEn*lEn-le2)-ab*(lEn-le)-cd*(std::exp(-d*lEn)-ele); |
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| 164 | } |
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| 165 | |
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| 166 | |
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| 167 | inline G4double |
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| 168 | G4ElectroNuclearCrossSection::HighEnergyJ2(G4double lEn) |
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| 169 | { |
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| 170 | static const G4double e=50000.; // E0 |
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| 171 | static const G4double le=std::log(e); // std::log(E0) |
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| 172 | static const G4double le1=(le-1.)*e; // (std::log(E0)-1)*E0 |
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| 173 | static const G4double a=.0375; // a |
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| 174 | static const G4double ab=a*16.5; // a*b |
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| 175 | static const G4double d=1.-0.11; // 1-d |
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| 176 | static const G4double cd=1.0734/d; // c/(1-d) |
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| 177 | static const G4double ele=std::exp(d*le); // E0^(1-d) |
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| 178 | G4double En=std::exp(lEn); |
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| 179 | return a*((lEn-1.)*En-le1)-ab*(En-e)+cd*(std::exp(d*lEn)-ele); |
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| 180 | } |
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| 181 | |
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| 182 | |
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| 183 | inline G4double |
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| 184 | G4ElectroNuclearCrossSection::HighEnergyJ3(G4double lEn) |
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| 185 | { |
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| 186 | static const G4double e=50000.; // E0 |
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| 187 | static const G4double le=std::log(e); // std::log(E0) |
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| 188 | static const G4double e2=e*e; // E0^2 |
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| 189 | static const G4double leh=(le-.5)*e2; // (std::log(E0)-.5)*E0^2 |
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| 190 | static const G4double ha=.0375*.5; // a/2 |
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| 191 | static const G4double hab=ha*16.5; // a*b/2 |
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| 192 | static const G4double d=2.-.11; // 2-d |
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| 193 | static const G4double cd=1.0734/d; // c/(2-d) |
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| 194 | static const G4double ele=std::exp(d*le); // E0^(2-d) |
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| 195 | G4double lastE2=std::exp(lEn+lEn); |
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| 196 | return ha*((lEn-.5)*lastE2-leh)-hab*(lastE2-e2)+cd*(std::exp(d*lEn)-ele); |
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| 197 | } |
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| 198 | |
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| 199 | #endif |
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