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>> 26 // $Id: G4PairProductionRelModel.hh 73607 2013-09-02 10:04:03Z gcosmo $
26 // 27 //
27 // ------------------------------------------- 28 // -------------------------------------------------------------------
28 // 29 //
29 // GEANT4 Class header file 30 // GEANT4 Class header file
30 // 31 //
31 // 32 //
32 // File name: G4PairProductionRelModel 33 // File name: G4PairProductionRelModel
33 // 34 //
34 // Author: Andreas Schaelicke 35 // Author: Andreas Schaelicke
35 // 36 //
36 // Creation date: 02.04.2009 37 // Creation date: 02.04.2009
37 // 38 //
38 // Modifications: 39 // Modifications:
39 // 28-05-18 New version with improved screenin <<
40 // LPM function approximation, effici <<
41 // Corrected call to selecting target <<
42 // (M. Novak) <<
43 // 40 //
44 // Class Description: 41 // Class Description:
45 // 42 //
46 // Implementation of gamma conversion to e+e- << 43 // Implementation of gamma convertion to e+e- in the field of a nucleus
47 // relativistic approximation 44 // relativistic approximation
48 // 45 //
49 46
50 // ------------------------------------------- 47 // -------------------------------------------------------------------
51 // 48 //
52 49
53 #ifndef G4PairProductionRelModel_h 50 #ifndef G4PairProductionRelModel_h
54 #define G4PairProductionRelModel_h 1 51 #define G4PairProductionRelModel_h 1
55 52
56 #include <CLHEP/Units/PhysicalConstants.h> 53 #include <CLHEP/Units/PhysicalConstants.h>
57 54
58 #include "G4VEmModel.hh" 55 #include "G4VEmModel.hh"
59 #include "G4Log.hh" << 56 #include "G4PhysicsTable.hh"
60 #include <vector> << 57 #include "G4NistManager.hh"
61 58
62 class G4ParticleChangeForGamma; 59 class G4ParticleChangeForGamma;
63 class G4Pow; <<
64 60
65 class G4PairProductionRelModel : public G4VEmM 61 class G4PairProductionRelModel : public G4VEmModel
66 { 62 {
67 63
68 public: 64 public:
69 65
70 explicit G4PairProductionRelModel(const G4Pa << 66 G4PairProductionRelModel(const G4ParticleDefinition* p = 0,
71 const G4St << 67 const G4String& nam = "BetheHeitlerLPM");
72 68
73 ~G4PairProductionRelModel() override; << 69 virtual ~G4PairProductionRelModel();
74 70
75 void Initialise(const G4ParticleDefinition*, << 71 virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);
76 72
77 void InitialiseLocal(const G4ParticleDefinit << 73 virtual void InitialiseLocal(const G4ParticleDefinition*,
78 G4VEmModel* masterModel) override; << 74 G4VEmModel* masterModel);
79 75
80 G4double ComputeCrossSectionPerAtom(const G4 << 76 virtual G4double ComputeCrossSectionPerAtom(
81 G4double kinEnergy, << 77 const G4ParticleDefinition*,
82 G4double Z, << 78 G4double kinEnergy,
83 G4double A=0., << 79 G4double Z,
84 G4double cut=0., << 80 G4double A=0.,
85 G4double emax=DBL_MAX) override; << 81 G4double cut=0.,
86 << 82 G4double emax=DBL_MAX);
87 void SampleSecondaries(std::vector<G4Dynamic << 83
88 const G4MaterialCutsCouple*, << 84 virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*,
89 const G4DynamicParticle*, << 85 const G4MaterialCutsCouple*,
90 G4double tmin, << 86 const G4DynamicParticle*,
91 G4double maxEnergy) override; << 87 G4double tmin,
92 << 88 G4double maxEnergy);
93 void SetupForMaterial(const G4ParticleDefini << 89
94 const G4Material*,G4double) override; << 90 virtual void SetupForMaterial(const G4ParticleDefinition*,
95 << 91 const G4Material*,G4double);
96 inline void SetLPMflag(G4bool val) { fIsUs << 92
97 inline G4bool LPMflag() const { retur << 93 // * fast inline functions *
98 << 94 inline void SetCurrentElement(G4double /*Z*/);
99 G4PairProductionRelModel & operator= << 95
100 (const G4PairProductionRelModel &right) = de << 96 // set / get methods
101 G4PairProductionRelModel(const G4PairProduc << 97 inline void SetLPMconstant(G4double val);
>> 98 inline G4double LPMconstant() const;
>> 99
>> 100 inline void SetLPMflag(G4bool);
>> 101 inline G4bool LPMflag() const;
102 102
103 protected: 103 protected:
104 104
105 // for evaluating screening related function << 105 // screening functions
106 inline void ComputePhi12(const G4double delt << 106 inline G4double Phi1(G4double delta) const;
107 G4double &phi1, G4double &phi2); << 107 inline G4double Phi2(G4double delta) const;
108 inline G4double ScreenFunction1(const G4doub << 108 inline G4double ScreenFunction1(G4double ScreenVariable);
109 inline G4double ScreenFunction2(const G4doub << 109 inline G4double ScreenFunction2(G4double ScreenVariable);
110 inline void ScreenFunction12(const G4double << 110 inline G4double DeltaMax() const;
111 G4double &f1, G4double &f2); << 111 inline G4double DeltaMin(G4double) const;
112 // helper methods for cross-section computat << 112
113 G4double ComputeParametrizedXSectionPerAtom( << 113 // lpm functions
114 G4double ComputeXSectionPerAtom(G4double gam << 114 void CalcLPMFunctions(G4double k, G4double eplus);
115 G4double ComputeDXSectionPerAtom(G4double ep << 115
116 G4double Z) << 116 G4double ComputeXSectionPerAtom(G4double totalEnergy, G4double Z);
117 G4double ComputeRelDXSectionPerAtom(G4double << 117
118 G4double gammaEnergy, G4double Z << 118 G4double ComputeDXSectionPerAtom(G4double eplusEnergy, G4double totalEnergy, G4double Z);
119 << 119 G4double ComputeRelDXSectionPerAtom(G4double eplusEnergy, G4double totalEnergy, G4double Z);
120 private: << 120
121 << 121 // hide assignment operator
122 // for creating some data structure per Z << 122 G4PairProductionRelModel & operator=(const G4PairProductionRelModel &right);
123 void InitialiseElementData(); << 123 G4PairProductionRelModel(const G4PairProductionRelModel&);
124 struct ElementData { << 124
125 G4double fLogZ13; << 125 G4NistManager* nist;
126 G4double fCoulomb; << 126
127 G4double fLradEl; << 127 G4ParticleDefinition* theGamma;
128 G4double fDeltaFactor; << 128 G4ParticleDefinition* theElectron;
129 G4double fDeltaMaxLow; << 129 G4ParticleDefinition* thePositron;
130 G4double fDeltaMaxHigh; << 130 G4ParticleChangeForGamma* fParticleChange;
131 G4double fEtaValue; << 131
132 G4double fLPMVarS1Cond; << 132 G4double fLPMconstant;
133 G4double fLPMILVarS1Cond; << 133 G4bool fLPMflag;
134 }; << 134
135 // for precomputing comp. intensive parts of << 135 // cash
136 // using them at run-time << 136 G4double z13, z23, lnZ;
137 void InitLPMFunctions(); << 137 G4double Fel, Finel, fCoulomb;
138 void ComputeLPMGsPhis(G4double &funcGS, G4do << 138 G4double currentZ;
139 const G4double varShat << 139
140 void GetLPMFunctions(G4double &lpmGs, G4doub << 140 // LPM effect
141 void ComputeLPMfunctions(G4double &fXiS, G4d << 141 G4double lpmEnergy;
142 const G4double eps, << 142 G4double xiLPM, phiLPM, gLPM;
143 const G4int izet); << 143
144 struct LPMFuncs { << 144 // consts
145 LPMFuncs() : fIsInitialized(false), fISDel << 145 G4bool use_completescreening;
146 G4bool fIsInitialized; << 146
147 G4double fISDelta; << 147 static const G4double xgi[8], wgi[8];
148 G4double fSLimit; << 148 static const G4double Fel_light[5];
149 std::vector<G4double> fLPMFuncG; << 149 static const G4double Finel_light[5];
150 std::vector<G4double> fLPMFuncPhi; << 150 static const G4double facFel;
151 }; << 151 static const G4double facFinel;
>> 152
>> 153 static const G4double preS1, logTwo;
152 154
153 protected: <<
154 static const G4int gMaxZet; <<
155 // <<
156 static const G4double gLPMconsta <<
157 // <<
158 static const G4double gXGL[8]; <<
159 static const G4double gWGL[8]; <<
160 static const G4double gFelLowZet <<
161 static const G4double gFinelLowZ <<
162 // <<
163 static const G4double gXSecFacto <<
164 static const G4double gEgLPMActi <<
165 // <<
166 static std::vector<ElementData*> gElementDa <<
167 static LPMFuncs gLPMFuncs; <<
168 // <<
169 G4bool isFirstInstance{false}; <<
170 G4bool fIsUseLPMC <<
171 G4bool fIsUseComp <<
172 // <<
173 G4double fLPMEnergy <<
174 // <<
175 G4double fParametri <<
176 G4double fCoulombCo <<
177 // <<
178 G4Pow* fG4Calc; <<
179 G4ParticleDefinition* fTheGamma; <<
180 G4ParticleDefinition* fTheElectr <<
181 G4ParticleDefinition* fThePositr <<
182 G4ParticleChangeForGamma* fParticleC <<
183 }; 155 };
184 // << 156
185 // Bethe screening functions for the elastic ( << 157
186 // Bethe's phi1, phi2 coherent screening funct << 158 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
187 // by using (the universal) atomic form factor << 159
188 // Fermi model of the atom (using numerical so << 160 inline
189 // screening function instead of Moliere's ana << 161 void G4PairProductionRelModel::SetLPMconstant(G4double val)
190 // numerical results can be well approximated << 162 {
191 // especially near the delta=1 limit) by: << 163 fLPMconstant = val;
192 // ## if delta <= 1.4 <<
193 // phi1(delta) = 20.806 - delta*(3.190 - 0.57 <<
194 // phi2(delta) = 20.234 - delta*(2.126 - 0.09 <<
195 // ## if delta > 1.4 <<
196 // phi1(delta) = phi2(delta) = 21.0190 - 4.14 <<
197 // with delta = 136mc^2kZ^{-1/3}/[E(Eg-E)] = 1 <<
198 // Eg is the initial photon energy, E is the t <<
199 // the e-/e+ pair, eps0 = mc^2/Eg and eps = E/ <<
200 <<
201 inline void G4PairProductionRelModel::ComputeP <<
202 G4double &phi1, <<
203 G4double &phi2) <<
204 { <<
205 if (delta > 1.4) { <<
206 phi1 = 21.0190 - 4.145*G4Log(delta + 0.9 <<
207 phi2 = phi1; <<
208 } else { <<
209 phi1 = 20.806 - delta*(3.190 - 0.5710*de <<
210 phi2 = 20.234 - delta*(2.126 - 0.0903*de <<
211 } <<
212 } 164 }
213 165
214 // Compute the value of the screening function << 166 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
215 inline G4double G4PairProductionRelModel::Scre << 167
>> 168 inline
>> 169 G4double G4PairProductionRelModel::LPMconstant() const
>> 170 {
>> 171 return fLPMconstant;
>> 172 }
>> 173
>> 174 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 175
>> 176 inline
>> 177 void G4PairProductionRelModel::SetLPMflag(G4bool val)
216 { 178 {
217 return (delta > 1.4) ? 42.038 - 8.29*G4Log(d << 179 fLPMflag = val;
218 : 42.184 - delta*(7.444 <<
219 } 180 }
220 181
221 // Compute the value of the screening function << 182 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
222 inline G4double G4PairProductionRelModel::Scre << 183
>> 184 inline
>> 185 G4bool G4PairProductionRelModel::LPMflag() const
223 { 186 {
224 return (delta > 1.4) ? 42.038 - 8.29*G4Log(d << 187 return fLPMflag;
225 : 41.326 - delta*(5.848 <<
226 } 188 }
227 189
228 // Same as ScreenFunction1 and ScreenFunction2 << 190 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
229 inline void G4PairProductionRelModel::ScreenFu << 191
230 << 192 inline void G4PairProductionRelModel::SetCurrentElement(G4double Z)
231 { 193 {
232 if (delta > 1.4) { << 194 if(Z != currentZ) {
233 f1 = 42.038 - 8.29*G4Log(delta + 0.958); << 195 currentZ = Z;
234 f2 = f1; << 196
235 } else { << 197 G4int iz = G4int(Z);
236 f1 = 42.184 - delta*(7.444 - 1.623*delta); << 198 z13 = nist->GetZ13(iz);
237 f2 = 41.326 - delta*(5.848 - 0.902*delta); << 199 z23 = z13*z13;
>> 200 lnZ = nist->GetLOGZ(iz);
>> 201
>> 202 if (iz <= 4) {
>> 203 Fel = Fel_light[iz];
>> 204 Finel = Finel_light[iz] ;
>> 205 }
>> 206 else {
>> 207 Fel = facFel - lnZ/3. ;
>> 208 Finel = facFinel - 2.*lnZ/3. ;
>> 209 }
>> 210 fCoulomb=GetCurrentElement()->GetfCoulomb();
238 } 211 }
239 } 212 }
>> 213
>> 214 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 215
>> 216 inline G4double G4PairProductionRelModel::Phi1(G4double delta) const
>> 217 {
>> 218 G4double screenVal;
>> 219
>> 220 if (delta > 1.)
>> 221 screenVal = 21.12 - 4.184*std::log(delta+0.952);
>> 222 else
>> 223 screenVal = 20.868 - delta*(3.242 - 0.625*delta);
>> 224
>> 225 return screenVal;
>> 226 }
>> 227
>> 228 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
>> 229
>> 230 inline G4double G4PairProductionRelModel::Phi2(G4double delta) const
>> 231 {
>> 232 G4double screenVal;
>> 233
>> 234 if (delta > 1.)
>> 235 screenVal = 21.12 - 4.184*std::log(delta+0.952);
>> 236 else
>> 237 screenVal = 20.209 - delta*(1.930 + 0.086*delta);
>> 238
>> 239 return screenVal;
>> 240 }
>> 241
>> 242 inline G4double G4PairProductionRelModel::ScreenFunction1(G4double ScreenVariable)
>> 243
>> 244 // compute the value of the screening function 3*PHI1 - PHI2
>> 245
>> 246 {
>> 247 G4double screenVal;
>> 248
>> 249 if (ScreenVariable > 1.)
>> 250 screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952);
>> 251 else
>> 252 screenVal = 42.392 - ScreenVariable*(7.796 - 1.961*ScreenVariable);
>> 253
>> 254 return screenVal;
>> 255 }
>> 256
>> 257 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
>> 258
>> 259 inline G4double G4PairProductionRelModel::ScreenFunction2(G4double ScreenVariable)
>> 260
>> 261 // compute the value of the screening function 1.5*PHI1 + 0.5*PHI2
>> 262
>> 263 {
>> 264 G4double screenVal;
>> 265
>> 266 if (ScreenVariable > 1.)
>> 267 screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952);
>> 268 else
>> 269 screenVal = 41.405 - ScreenVariable*(5.828 - 0.8945*ScreenVariable);
>> 270
>> 271 return screenVal;
>> 272 }
>> 273
>> 274 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
>> 275
>> 276
>> 277 inline G4double G4PairProductionRelModel::DeltaMax() const
>> 278 {
>> 279 // k > 50 MeV
>> 280 G4double FZ = 8.*(lnZ/3. + fCoulomb);
>> 281 return std::exp( (42.24-FZ)/8.368 ) + 0.952;
>> 282 }
>> 283
>> 284 inline G4double G4PairProductionRelModel::DeltaMin(G4double k) const
>> 285 {
>> 286 return 4.*136./z13*(CLHEP::electron_mass_c2/k);
>> 287 }
>> 288
>> 289
240 290
241 #endif 291 #endif
242 292