source: trunk/source/processes/hadronic/cross_sections/include/G4ElectroNuclearCrossSection.hh@ 1347

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1//
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26//
27// GEANT4 tag $Name: hadr-cross-V09-03-12 $
28//
29//
30// GEANT4 physics class: G4ElectroNuclearCrossSection -- header file
31// M.V. Kossov, ITEP(Moscow), 24-OCT-01
32// The last update: M.V. Kossov, CERN/ITEP (Moscow) 25-Sept-03
33//
34
35#ifndef G4ElectroNuclearCrossSection_h
36#define G4ElectroNuclearCrossSection_h 1
37
38#include "G4VCrossSectionDataSet.hh"
39#include "G4DynamicParticle.hh"
40#include "G4Element.hh"
41#include "G4ParticleTable.hh"
42#include "G4NucleiProperties.hh"
43#include <vector>
44#include "Randomize.hh"
45#include "G4Electron.hh"
46#include "G4Positron.hh"
47
48class G4ElectroNuclearCrossSection : public G4VCrossSectionDataSet
49{
50public:
51
52 G4ElectroNuclearCrossSection();
53 virtual ~G4ElectroNuclearCrossSection();
54
55 G4bool IsApplicable(const G4DynamicParticle* aParticle, const G4Element* )
56 {
57 return IsIsoApplicable(aParticle, 0, 0);
58 }
59
60 G4bool IsIsoApplicable(const G4DynamicParticle* aParticle,
61 G4int /*ZZ*/, G4int /*AA*/)
62 {
63 G4bool result = false;
64 if (aParticle->GetDefinition() == G4Electron::ElectronDefinition())
65 result = true;
66 if (aParticle->GetDefinition() == G4Positron::PositronDefinition())
67 result = true;
68 return result;
69 }
70
71
72 G4double GetCrossSection(const G4DynamicParticle* aParticle,
73 const G4Element* anElement, G4double T=0.);
74
75 G4double GetZandACrossSection(const G4DynamicParticle* aParticle,
76 G4int ZZ, G4int AA, G4double T=0.);
77
78 G4double GetEquivalentPhotonEnergy();
79
80 G4double GetVirtualFactor(G4double nu, G4double Q2);
81
82 G4double GetEquivalentPhotonQ2(G4double nu);
83
84 void BuildPhysicsTable(const G4ParticleDefinition&) {}
85
86 void DumpPhysicsTable(const G4ParticleDefinition&) {}
87
88private:
89 G4int GetFunctions(G4double a, G4double* x, G4double* y, G4double* z);
90
91 G4double ThresholdEnergy(G4int Z, G4int N);
92 G4double HighEnergyJ1(G4double lE);
93 G4double HighEnergyJ2(G4double lE);
94 G4double HighEnergyJ3(G4double lE);
95 G4double SolveTheEquation(G4double f);
96 G4double Fun(G4double x);
97 G4double DFun(G4double x);
98
99// Body
100private:
101 static G4int lastN; // The last N of calculated nucleus
102 static G4int lastZ; // The last Z of calculated nucleus
103 static G4int lastF; // Last used in the cross section TheFirstBin
104 static G4double* lastJ1; // Pointer to the last array of the J1 function
105 static G4double* lastJ2; // Pointer to the last array of the J2 function
106 static G4double* lastJ3; // Pointer to the last array of the J3 function
107 static G4int lastL; // Last used in the cross section TheLastBin
108 static G4double lastE; // Last used in the cross section Energy
109 static G4double lastTH; // Last value of the Energy Threshold
110 static G4double lastSig; // Last value of the Cross Section
111 static G4double lastG; // Last value of gamma=lnE-ln(me)
112 static G4double lastH; // Last value of the High energy A-dependence
113
114 // Vector of pointers to the J1 tabulated functions
115 static std::vector <G4double*> J1;
116
117 // Vector of pointers to the J2 tabulated functions
118 static std::vector <G4double*> J2;
119
120 // Vector of pointers to the J3 tabulated functions
121 static std::vector <G4double*> J3;
122};
123
124
125inline G4double
126G4ElectroNuclearCrossSection::DFun(G4double x)
127{
128 // Parametrization of the PhotoNucCS
129 static const G4double shd=1.0734; // HE PomShadowing(D)
130 static const G4double poc=0.0375; // HE Pomeron coefficient
131 static const G4double pos=16.5; // HE Pomeron shift
132 static const G4double reg=.11; // HE Reggeon slope
133 static const G4double mel=0.5109989; // Mass of an electron in MeV
134 static const G4double lmel=std::log(mel); // Log of an electron mass
135 G4double y=std::exp(x-lastG-lmel); // y for the x
136 G4double flux=lastG*(2.-y*(2.-y))-1.; // flux factor
137 return (poc*(x-pos)+shd*std::exp(-reg*x))*flux;
138}
139
140
141inline G4double
142G4ElectroNuclearCrossSection::Fun(G4double x)
143{
144 // Integrated PhoNuc cross section
145 G4double dlg1=lastG+lastG-1.;
146 G4double lgoe=lastG/lastE;
147 G4double HE2=HighEnergyJ2(x);
148 return dlg1*HighEnergyJ1(x)-lgoe*(HE2+HE2-HighEnergyJ3(x)/lastE);
149}
150
151
152inline G4double
153G4ElectroNuclearCrossSection::HighEnergyJ1(G4double lEn)
154{
155 static const G4double le=std::log(50000.); // std::log(E0)
156 static const G4double le2=le*le; // std::log(E0)^2
157 static const G4double a=.0375; // a
158 static const G4double ha=a*.5; // a/2
159 static const G4double ab=a*16.5; // a*b
160 static const G4double d=0.11; // d
161 static const G4double cd=1.0734/d; // c/d
162 static const G4double ele=std::exp(-d*le); // E0^(-d)
163 return ha*(lEn*lEn-le2)-ab*(lEn-le)-cd*(std::exp(-d*lEn)-ele);
164}
165
166
167inline G4double
168G4ElectroNuclearCrossSection::HighEnergyJ2(G4double lEn)
169{
170 static const G4double e=50000.; // E0
171 static const G4double le=std::log(e); // std::log(E0)
172 static const G4double le1=(le-1.)*e; // (std::log(E0)-1)*E0
173 static const G4double a=.0375; // a
174 static const G4double ab=a*16.5; // a*b
175 static const G4double d=1.-0.11; // 1-d
176 static const G4double cd=1.0734/d; // c/(1-d)
177 static const G4double ele=std::exp(d*le); // E0^(1-d)
178 G4double En=std::exp(lEn);
179 return a*((lEn-1.)*En-le1)-ab*(En-e)+cd*(std::exp(d*lEn)-ele);
180}
181
182
183inline G4double
184G4ElectroNuclearCrossSection::HighEnergyJ3(G4double lEn)
185{
186 static const G4double e=50000.; // E0
187 static const G4double le=std::log(e); // std::log(E0)
188 static const G4double e2=e*e; // E0^2
189 static const G4double leh=(le-.5)*e2; // (std::log(E0)-.5)*E0^2
190 static const G4double ha=.0375*.5; // a/2
191 static const G4double hab=ha*16.5; // a*b/2
192 static const G4double d=2.-.11; // 2-d
193 static const G4double cd=1.0734/d; // c/(2-d)
194 static const G4double ele=std::exp(d*le); // E0^(2-d)
195 G4double lastE2=std::exp(lEn+lEn);
196 return ha*((lEn-.5)*lastE2-leh)-hab*(lastE2-e2)+cd*(std::exp(d*lEn)-ele);
197}
198
199#endif
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