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25 //
26 // Neutron-electron elastic cross section base on the integration of
27 // the Rosenbluth differential xsc
28 //
29 // 16.05.17 V. Grichine
30 //
31 //
32
33 #ifndef G4NeutronElectronElXsc_h
34 #define G4NeutronElectronElXsc_h
35
36
37 #include "globals.hh"
38 #include "G4VCrossSectionDataSet.hh"
39 #include "G4DynamicParticle.hh"
40
41 // class G4ParticleDefinition;
42 class G4PhysicsLogVector;
43 class G4PhysicsTable;
44
45 class G4NeutronElectronElXsc : public G4VCrossSectionDataSet
46 {
47 public:
48
49 G4NeutronElectronElXsc();
50 ~G4NeutronElectronElXsc();
51
52 void Initialise();
53
54 virtual
55 G4bool IsElementApplicable(const G4DynamicParticle*, G4int Z, const G4Material*);
56
57
58 virtual
59 G4double GetElementCrossSection(const G4DynamicParticle*,
60 G4int Z, const G4Material*);
61
62 G4double GetRosenbluthXsc(const G4DynamicParticle*,
63 G4int Z, const G4Material*);
64
65 G4double XscIntegrand(G4double x);
66
67 G4double GetElementNonRelXsc(const G4DynamicParticle*,
68 G4int Z, const G4Material*);
69
70 G4double CalculateAm( G4double momentum);
71
72 inline G4double GetAm(){return fAm;};
73
74 void SetCutEnergy(G4double ec){fCutEnergy=ec;};
75 G4double GetCutEnergy(){return fCutEnergy;};
76
77 void SetBiasingFactor(G4double bf){fBiasingFactor=bf;};
78
79 protected:
80 G4double fM, fM2, fMv2, fme, fme2, fee, fee2;
81 G4double fCofXsc; //
82 G4double fAm; //
83 G4int fEnergyBin;
84 G4double fMinEnergy, fMaxEnergy, fCutEnergy; // minimal recoil electron energy detected
85 G4double fBiasingFactor; // biasing xsc up
86
87 G4PhysicsLogVector* fEnergyXscVector;
88 static const G4double fXscArray[200];
89 };
90
91
92
93 ////////////////////////////////////////////////////////////////////
94 //
95 // return Wentzel atom screening correction for neutron-electron scattering
96
97 inline G4double G4NeutronElectronElXsc::CalculateAm( G4double momentum)
98 {
99 G4double k = momentum/CLHEP::hbarc;
100 G4double ch = 1.13;
101 G4double zn = 1.77*k*CLHEP::Bohr_radius;
102 G4double zn2 = zn*zn;
103 fAm = ch/zn2;
104
105 return fAm;
106 }
107
108 ////////////////////////////////////////////////////
109 //
110 // Slow electron (Tkin << me_c2) in the neutron rest frame
111
112 inline G4double G4NeutronElectronElXsc::
113 GetElementNonRelXsc(const G4DynamicParticle* aPart, G4int ZZ,
114 const G4Material*)
115 {
116 G4double result(0.), te(0.), momentum(0.);
117
118 te = aPart->GetKineticEnergy()*fme/fM;
119 momentum = std::sqrt( te*(te + 2.*fme) );
120 fAm = CalculateAm(momentum);
121
122 result = 1. + std::log(1. +1./fAm);
123 result *= fCofXsc; //*energy;
124 result *= ZZ; // incoherent sum over all element electrons
125
126 return result;
127 }
128
129 #endif
130