source: trunk/source/processes/electromagnetic/standard/include/G4PairProductionRelModel.hh@ 1330

Last change on this file since 1330 was 1228, checked in by garnier, 16 years ago

update geant4.9.3 tag
File size: 8.3 KB
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1//
2// ********************************************************************
3// * License and Disclaimer *
4// * *
5// * The Geant4 software is copyright of the Copyright Holders of *
6// * the Geant4 Collaboration. It is provided under the terms and *
7// * conditions of the Geant4 Software License, included in the file *
8// * LICENSE and available at http://cern.ch/geant4/license . These *
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14// * regarding this software system or assume any liability for its *
15// * use. Please see the license in the file LICENSE and URL above *
16// * for the full disclaimer and the limitation of liability. *
17// * *
18// * This code implementation is the result of the scientific and *
19// * technical work of the GEANT4 collaboration. *
20// * By using, copying, modifying or distributing the software (or *
21// * any work based on the software) you agree to acknowledge its *
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23// * acceptance of all terms of the Geant4 Software license. *
24// ********************************************************************
25//
26// $Id: G4PairProductionRelModel.hh,v 1.3 2009/06/04 13:45:53 gunter Exp $
27// GEANT4 tag $Name: geant4-09-03 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class header file
32//
33//
34// File name: G4PairProductionRelModel
35//
36// Author: Andreas Schaelicke
37//
38// Creation date: 02.04.2009
39//
40// Modifications:
41//
42// Class Description:
43//
44// Implementation of gamma convertion to e+e- in the field of a nucleus
45// relativistic approximation
46//
47
48// -------------------------------------------------------------------
49//
50
51#ifndef G4PairProductionRelModel_h
52#define G4PairProductionRelModel_h 1
53
54#include "G4VEmModel.hh"
55#include "G4PhysicsTable.hh"
56#include "G4NistManager.hh"
57
58class G4ParticleChangeForGamma;
59
60class G4PairProductionRelModel : public G4VEmModel
61{
62
63public:
64
65 G4PairProductionRelModel(const G4ParticleDefinition* p = 0,
66 const G4String& nam = "Bethe-Heitler");
67
68 virtual ~G4PairProductionRelModel();
69
70 virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);
71
72 virtual G4double ComputeCrossSectionPerAtom(
73 const G4ParticleDefinition*,
74 G4double kinEnergy,
75 G4double Z,
76 G4double A=0.,
77 G4double cut=0.,
78 G4double emax=DBL_MAX);
79
80 virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*,
81 const G4MaterialCutsCouple*,
82 const G4DynamicParticle*,
83 G4double tmin,
84 G4double maxEnergy);
85
86 virtual void SetupForMaterial(const G4ParticleDefinition*,
87 const G4Material*,G4double);
88
89 // * fast inline functions *
90 inline void SetCurrentElement(const G4double);
91
92 // set / get methods
93 inline void SetLPMconstant(G4double val);
94 inline G4double LPMconstant() const;
95
96 inline void SetLPMflag(G4bool);
97 inline G4bool LPMflag() const;
98
99protected:
100 // screening functions
101 inline G4double Phi1(G4double delta) const;
102 inline G4double Phi2(G4double delta) const;
103 inline G4double DeltaMax() const;
104 inline G4double DeltaMin(G4double) const;
105 // lpm functions
106 void CalcLPMFunctions(G4double k, G4double eplus);
107
108 // obsolete
109 G4double ScreenFunction1(G4double ScreenVariable);
110 G4double ScreenFunction2(G4double ScreenVariable);
111
112
113
114
115 G4double ComputeXSectionPerAtom(G4double totalEnergy, G4double Z);
116
117 G4double ComputeDXSectionPerAtom(G4double eplusEnergy, G4double totalEnergy, G4double Z);
118 G4double ComputeRelDXSectionPerAtom(G4double eplusEnergy, G4double totalEnergy, G4double Z);
119
120 // hide assignment operator
121 G4PairProductionRelModel & operator=(const G4PairProductionRelModel &right);
122 G4PairProductionRelModel(const G4PairProductionRelModel&);
123
124 G4NistManager* nist;
125
126 G4ParticleDefinition* theGamma;
127 G4ParticleDefinition* theElectron;
128 G4ParticleDefinition* thePositron;
129 G4ParticleChangeForGamma* fParticleChange;
130 G4PhysicsTable* theCrossSectionTable;
131
132 G4double lowGammaEnergy;
133 G4double highGammaEnergy;
134
135 G4int nbins;
136 size_t indexZ[120];
137
138 G4double fLPMconstant;
139 G4bool fLPMflag;
140
141 // cash
142 G4double z13, z23, lnZ;
143 G4double Fel, Finel, fCoulomb;
144 G4double currentZ;
145
146 // LPM effect
147 G4double lpmEnergy;
148 G4double xiLPM, phiLPM, gLPM;
149
150 // consts
151 G4bool use_completescreening;
152
153 static const G4double xgi[8], wgi[8];
154 static const G4double Fel_light[5];
155 static const G4double Finel_light[5];
156 static const G4double facFel;
157 static const G4double facFinel;
158
159 static const G4double preS1, logTwo;
160
161};
162
163
164//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
165
166inline
167void G4PairProductionRelModel::SetLPMconstant(G4double val)
168{
169 fLPMconstant = val;
170}
171
172//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
173
174inline
175G4double G4PairProductionRelModel::LPMconstant() const
176{
177 return fLPMconstant;
178}
179
180//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
181
182inline
183void G4PairProductionRelModel::SetLPMflag(G4bool val)
184{
185 fLPMflag = val;
186}
187
188//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
189
190inline
191G4bool G4PairProductionRelModel::LPMflag() const
192{
193 return fLPMflag;
194}
195
196//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
197
198inline void G4PairProductionRelModel::SetCurrentElement(const G4double Z)
199{
200 if(Z != currentZ) {
201 currentZ = Z;
202
203 G4int iz = G4int(Z);
204 z13 = nist->GetZ13(iz);
205 z23 = z13*z13;
206 lnZ = nist->GetLOGZ(iz);
207
208 if (iz <= 4) {
209 Fel = Fel_light[iz];
210 Finel = Finel_light[iz] ;
211 }
212 else {
213 Fel = facFel - lnZ/3. ;
214 Finel = facFinel - 2.*lnZ/3. ;
215 }
216
217 fCoulomb=GetCurrentElement()->GetfCoulomb();
218 }
219}
220//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
221
222inline G4double G4PairProductionRelModel::Phi1(G4double delta) const
223{
224 G4double screenVal;
225
226 if (delta > 1.)
227 screenVal = 21.12 - 4.184*std::log(delta+0.952);
228 else
229 screenVal = 20.868 - delta*(3.242 - 0.625*delta);
230
231 return screenVal;
232}
233
234//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
235
236inline G4double G4PairProductionRelModel::Phi2(G4double delta) const
237{
238 G4double screenVal;
239
240 if (delta > 1.)
241 screenVal = 21.12 - 4.184*std::log(delta+0.952);
242 else
243 screenVal = 20.209 - delta*(1.930 + 0.086*delta);
244
245 return screenVal;
246}
247
248inline G4double G4PairProductionRelModel::ScreenFunction1(G4double ScreenVariable)
249
250// compute the value of the screening function 3*PHI1 - PHI2
251
252{
253 G4double screenVal;
254
255 if (ScreenVariable > 1.)
256 screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952);
257 else
258 screenVal = 42.392 - ScreenVariable*(7.796 - 1.961*ScreenVariable);
259
260 return screenVal;
261}
262
263//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
264
265inline G4double G4PairProductionRelModel::ScreenFunction2(G4double ScreenVariable)
266
267// compute the value of the screening function 1.5*PHI1 + 0.5*PHI2
268
269{
270 G4double screenVal;
271
272 if (ScreenVariable > 1.)
273 screenVal = 42.24 - 8.368*std::log(ScreenVariable+0.952);
274 else
275 screenVal = 41.405 - ScreenVariable*(5.828 - 0.8945*ScreenVariable);
276
277 return screenVal;
278}
279
280//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
281
282
283inline G4double G4PairProductionRelModel::DeltaMax() const
284{
285 // k > 50 MeV
286 G4double FZ = 8.*(lnZ/3. + fCoulomb);
287 return std::exp( (42.24-FZ)/8.368 ) + 0.952;
288}
289
290inline G4double G4PairProductionRelModel::DeltaMin(G4double k) const
291{
292 return 4.*136./z13*(electron_mass_c2/k);
293}
294
295
296
297#endif
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