// // ******************************************************************** // * License and Disclaimer * // * * // * The Geant4 software is copyright of the Copyright Holders of * // * the Geant4 Collaboration. It is provided under the terms and * // * conditions of the Geant4 Software License, included in the file * // * LICENSE and available at http://cern.ch/geant4/license . These * // * include a list of copyright holders. * // * * // * Neither the authors of this software system, nor their employing * // * institutes,nor the agencies providing financial support for this * // * work make any representation or warranty, express or implied, * // * regarding this software system or assume any liability for its * // * use. Please see the license in the file LICENSE and URL above * // * for the full disclaimer and the limitation of liability. * // * * // * This code implementation is the result of the scientific and * // * technical work of the GEANT4 collaboration. * // * By using, copying, modifying or distributing the software (or * // * any work based on the software) you agree to acknowledge its * // * use in resulting scientific publications, and indicate your * // * acceptance of all terms of the Geant4 Software license. * // ******************************************************************** // // // GEANT4 tag $Name: geant4-09-03-beta-cand-01 $ // // // GEANT4 physics class: G4QElectronNuclearCrossSection -- header file // M.V. Kossov, ITEP(Moscow), 24-OCT-01 // The last update: M.V. Kossov, CERN/ITEP (Moscow) 25-Sept-03 // // -------------------------------------------------------------------------------- // Short description: reaction cross-sections for electron-nuclear reactions, which // are integrals over virtual equivalent photons photons. // -------------------------------------------------------------------------------- #ifndef G4QElectronNuclearCrossSection_h #define G4QElectronNuclearCrossSection_h 1 #include "G4VCrossSectionDataSet.hh" #include "G4DynamicParticle.hh" #include "G4Element.hh" #include "G4ParticleTable.hh" #include "G4NucleiProperties.hh" #include #include "Randomize.hh" #include "G4Electron.hh" #include "G4Positron.hh" #include "G4VQCrossSection.hh" class G4QElectronNuclearCrossSection : public G4VQCrossSection { protected: G4QElectronNuclearCrossSection() {} // Constructor public: ~G4QElectronNuclearCrossSection() {} static G4VQCrossSection* GetPointer(); // Gives a pointer to this singletone G4double ThresholdEnergy(G4int Z, G4int N, G4int PDG=11); // At present momentum (pMom) must be in GeV (@@ Units) virtual G4double GetCrossSection(G4bool fCS, G4double pMom, G4int tgZ, G4int tgN, G4int pPDG=0); G4double CalculateCrossSection(G4bool CS, G4int F, G4int I, G4int PDG, G4int Z, G4int N, G4double Momentum); G4int GetExchangePDGCode(); G4double GetExchangeEnergy(); G4double GetVirtualFactor(G4double nu, G4double Q2); G4double GetExchangeQ2(G4double nu); private: G4int GetFunctions(G4double a, G4double* x, G4double* y, G4double* z); G4double HighEnergyJ1(G4double lE); G4double HighEnergyJ2(G4double lE); G4double HighEnergyJ3(G4double lE); G4double SolveTheEquation(G4double f); G4double Fun(G4double x); G4double DFun(G4double x); // Body private: static G4bool onlyCS; // flag to calculate only CrossSection static G4double lastSig; // Last calculated cross section static G4int lastL; // Last used in the cross section TheLastBin static G4double lastE; // Last used in the cross section Energy static G4int lastF; // Last used in the cross section TheFirstBin static G4double lastG; // Last value of gamma=lnE-ln(m) static G4double lastH; // Last value of the High energy A-dependence static G4double* lastJ1; // Pointer to the last array of the J1 function static G4double* lastJ2; // Pointer to the last array of the J2 function static G4double* lastJ3; // Pointer to the last array of the J3 function static G4int lastPDG; // The last projectile PDG static G4int lastN; // The last N of calculated nucleus static G4int lastZ; // The last Z of calculated nucleus static G4double lastP; // Last used in the cross section Momentum static G4double lastTH; // Last value of the Momentum Threshold static G4double lastCS; // Last value of the Cross Section static G4int lastI; // The last position in the DAMDB }; inline G4double G4QElectronNuclearCrossSection::DFun(G4double x)//PhotoNucCSParametrization { static const G4double shd=1.0734; // HE PomShadowing(D) static const G4double poc=0.0375; // HE Pomeron coefficient static const G4double pos=16.5; // HE Pomeron shift static const G4double reg=.11; // HE Reggeon slope static const G4double mel=0.5109989; // Mass of an electron in MeV static const G4double lmel=std::log(mel); // Log of an electron mass G4double y=std::exp(x-lastG-lmel); // y for the x G4double flux=lastG*(2.-y*(2.-y))-1.; // flux factor return (poc*(x-pos)+shd*std::exp(-reg*x))*flux; } inline G4double G4QElectronNuclearCrossSection::Fun(G4double x) // Integrated PhoNucCS { G4double dlg1=lastG+lastG-1.; G4double lgoe=lastG/lastE; G4double HE2=HighEnergyJ2(x); return dlg1*HighEnergyJ1(x)-lgoe*(HE2+HE2-HighEnergyJ3(x)/lastE); } inline G4double G4QElectronNuclearCrossSection::HighEnergyJ1(G4double lEn) { static const G4double le=std::log(50000.); // log(E0) static const G4double le2=le*le; // log(E0)^2 static const G4double a=.0375; // a static const G4double ha=a*.5; // a/2 static const G4double ab=a*16.5; // a*b static const G4double d=0.11; // d static const G4double cd=1.0734/d; // c/d static const G4double ele=std::exp(-d*le); // E0^(-d) return ha*(lEn*lEn-le2)-ab*(lEn-le)-cd*(std::exp(-d*lEn)-ele); } inline G4double G4QElectronNuclearCrossSection::HighEnergyJ2(G4double lEn) { static const G4double e=50000.; // E0 static const G4double le=std::log(e); // log(E0) static const G4double le1=(le-1.)*e; // (log(E0)-1)*E0 static const G4double a=.0375; // a static const G4double ab=a*16.5; // a*b static const G4double d=1.-0.11; // 1-d static const G4double cd=1.0734/d; // c/(1-d) static const G4double ele=std::exp(d*le); // E0^(1-d) G4double En=std::exp(lEn); return a*((lEn-1.)*En-le1)-ab*(En-e)+cd*(std::exp(d*lEn)-ele); } inline G4double G4QElectronNuclearCrossSection::HighEnergyJ3(G4double lEn) { static const G4double e=50000.; // E0 static const G4double le=std::log(e); // log(E0) static const G4double e2=e*e; // E0^2 static const G4double leh=(le-.5)*e2; // (log(E0)-.5)*E0^2 static const G4double ha=.0375*.5; // a/2 static const G4double hab=ha*16.5; // a*b/2 static const G4double d=2.-.11; // 2-d static const G4double cd=1.0734/d; // c/(2-d) static const G4double ele=std::exp(d*le); // E0^(2-d) G4double lastE2=std::exp(lEn+lEn); return ha*((lEn-.5)*lastE2-leh)-hab*(lastE2-e2)+cd*(std::exp(d*lEn)-ele); } #endif