include/Geant4/G4NeutronElectronElXsc.hh

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0025 //
0026 // Neutron-electron elastic cross section base on the integration of
0027 // the Rosenbluth differential xsc
0028 //
0029 // 16.05.17 V. Grichine
0030 //
0031 //
0032
0033 #ifndef G4NeutronElectronElXsc_h
0034 #define G4NeutronElectronElXsc_h
0035
0036
0037 #include "globals.hh"
0038 #include "G4VCrossSectionDataSet.hh"
0039 #include "G4DynamicParticle.hh"
0040
0041 // class G4ParticleDefinition;
0042 class G4PhysicsLogVector;
0043 class G4PhysicsTable;
0044
0045 class G4NeutronElectronElXsc : public G4VCrossSectionDataSet
0046 {
0047 public:
0048
0049   G4NeutronElectronElXsc();
0050   ~G4NeutronElectronElXsc();
0051
0052   void Initialise();
0053
0054   virtual
0055   G4bool IsElementApplicable(const G4DynamicParticle*, G4int Z, const G4Material*);
0056
0057
0058   virtual
0059   G4double GetElementCrossSection(const G4DynamicParticle*,
0060                   G4int Z, const G4Material*);
0061
0062   G4double GetRosenbluthXsc(const G4DynamicParticle*,
0063                   G4int Z, const G4Material*);
0064
0065   G4double XscIntegrand(G4double x);
0066
0067    G4double GetElementNonRelXsc(const G4DynamicParticle*,
0068                   G4int Z, const G4Material*);
0069
0070   G4double CalculateAm( G4double momentum);
0071
0072   inline G4double GetAm(){return fAm;};
0073
0074   void SetCutEnergy(G4double ec){fCutEnergy=ec;};
0075   G4double GetCutEnergy(){return fCutEnergy;};
0076
0077   void SetBiasingFactor(G4double bf){fBiasingFactor=bf;};
0078
0079 protected:
0080   G4double fM, fM2, fMv2, fme, fme2, fee, fee2;
0081   G4double fCofXsc;    //
0082   G4double fAm;    //
0083   G4int fEnergyBin;
0084   G4double fMinEnergy, fMaxEnergy, fCutEnergy; // minimal recoil electron energy detected
0085   G4double fBiasingFactor; // biasing xsc up
0086
0087   G4PhysicsLogVector* fEnergyXscVector;
0088   static const G4double fXscArray[200];
0089 };
0090
0091
0092
0093 ////////////////////////////////////////////////////////////////////
0094 //
0095 // return Wentzel atom screening correction for neutron-electron scattering
0096
0097 inline  G4double G4NeutronElectronElXsc::CalculateAm( G4double momentum)
0098 {
0099   G4double k   = momentum/CLHEP::hbarc;
0100   G4double ch  = 1.13;
0101   G4double zn  = 1.77*k*CLHEP::Bohr_radius;
0102   G4double zn2 = zn*zn;
0103   fAm          = ch/zn2;
0104
0105   return fAm;
0106 }
0107
0108 ////////////////////////////////////////////////////
0109 //
0110 // Slow electron (Tkin << me_c2) in the neutron rest frame
0111
0112 inline G4double G4NeutronElectronElXsc::
0113 GetElementNonRelXsc(const G4DynamicParticle* aPart, G4int ZZ,
0114                const G4Material*)
0115 {
0116   G4double result(0.), te(0.), momentum(0.);
0117
0118   te = aPart->GetKineticEnergy()*fme/fM;
0119   momentum = std::sqrt( te*(te + 2.*fme) );
0120   fAm = CalculateAm(momentum);
0121
0122   result = 1. + std::log(1. +1./fAm);
0123   result *= fCofXsc; //*energy;
0124   result *= ZZ;  // incoherent sum over  all element electrons
0125
0126   return result;
0127 }
0128
0129 #endif