source: trunk/source/processes/electromagnetic/standard/include/G4eCoulombScatteringModel.hh@ 1193

Last change on this file since 1193 was 1055, checked in by garnier, 17 years ago

maj sur la beta de geant 4.9.3
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1//
2// ********************************************************************
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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 *
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25//
26// $Id: G4eCoulombScatteringModel.hh,v 1.43 2009/05/10 16:09:29 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-03-beta-cand-01 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class header file
32//
33//
34// File name: G4eCoulombScatteringModel
35//
36// Author: Vladimir Ivanchenko
37//
38// Creation date: 19.02.2006
39//
40// Modifications:
41// 01.08.06 V.Ivanchenko extend upper limit of table to TeV and review the
42// logic of building - only elements from G4ElementTable
43// 08.08.06 V.Ivanchenko build internal table in ekin scale, introduce faclim
44// 19.08.06 V.Ivanchenko add inline function ScreeningParameter and
45// make some members protected
46// 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e-
47// 09.06.08 V.Ivanchenko add SelectIsotope and sampling of the recoil ion
48//
49// Class Description:
50//
51// Implementation of eCoulombScattering of pointlike charge particle
52// on Atomic Nucleus for interval of scattering anles in Lab system
53// thetaMin - ThetaMax, nucleus recoil is neglected.
54// The model based on analysis of J.M.Fernandez-Varea et al.
55// NIM B73(1993)447 originated from G.Wentzel Z.Phys. 40(1927)590 with
56// screening parameter from H.A.Bethe Phys. Rev. 89 (1953) 1256.
57//
58
59// -------------------------------------------------------------------
60//
61
62#ifndef G4eCoulombScatteringModel_h
63#define G4eCoulombScatteringModel_h 1
64
65#include "G4VEmModel.hh"
66#include "G4PhysicsTable.hh"
67#include "globals.hh"
68#include "G4NistManager.hh"
69
70class G4ParticleChangeForGamma;
71class G4ParticleDefinition;
72
73class G4eCoulombScatteringModel : public G4VEmModel
74{
75
76public:
77
78 G4eCoulombScatteringModel(const G4String& nam = "eCoulombScattering");
79
80 virtual ~G4eCoulombScatteringModel();
81
82 virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);
83
84 virtual G4double ComputeCrossSectionPerAtom(
85 const G4ParticleDefinition*,
86 G4double kinEnergy,
87 G4double Z,
88 G4double A,
89 G4double cut,
90 G4double emax);
91
92 virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*,
93 const G4MaterialCutsCouple*,
94 const G4DynamicParticle*,
95 G4double tmin,
96 G4double maxEnergy);
97
98 inline void SetRecoilThreshold(G4double eth);
99
100protected:
101
102 G4double CrossSectionPerAtom();
103
104 G4double SampleCosineTheta();
105
106 inline void DefineMaterial(const G4MaterialCutsCouple*);
107
108 inline void SetupParticle(const G4ParticleDefinition*);
109
110 inline void SetupKinematic(G4double kinEnergy, G4double cut);
111
112 inline void SetupTarget(G4double Z, G4double kinEnergy);
113
114private:
115
116 void ComputeMaxElectronScattering(G4double cut);
117
118 // hide assignment operator
119 G4eCoulombScatteringModel & operator=(const G4eCoulombScatteringModel &right);
120 G4eCoulombScatteringModel(const G4eCoulombScatteringModel&);
121
122protected:
123
124 const G4ParticleDefinition* theProton;
125 const G4ParticleDefinition* theElectron;
126 const G4ParticleDefinition* thePositron;
127
128 G4ParticleTable* theParticleTable;
129 G4ParticleChangeForGamma* fParticleChange;
130 G4NistManager* fNistManager;
131 const G4DataVector* currentCuts;
132
133 const G4MaterialCutsCouple* currentCouple;
134 const G4Material* currentMaterial;
135 const G4Element* currentElement;
136 G4int currentMaterialIndex;
137
138 G4double coeff;
139 G4double cosThetaMin;
140 G4double cosThetaMax;
141 G4double cosTetMinNuc;
142 G4double cosTetMaxNuc;
143 G4double cosTetMaxNuc2;
144 G4double cosTetMaxElec;
145 G4double cosTetMaxElec2;
146 G4double q2Limit;
147 G4double recoilThreshold;
148 G4double elecXSection;
149 G4double nucXSection;
150 G4double ecut;
151
152 // projectile
153 const G4ParticleDefinition* particle;
154
155 G4double chargeSquare;
156 G4double spin;
157 G4double mass;
158 G4double tkin;
159 G4double mom2;
160 G4double invbeta2;
161 G4double kinFactor;
162 G4double etag;
163 G4double lowEnergyLimit;
164
165 // target
166 G4double targetZ;
167 G4double targetMass;
168 G4double screenZ;
169 G4double formfactA;
170 G4int idxelm;
171 G4int iz;
172
173private:
174
175 G4double alpha2;
176 G4double faclim;
177
178 static G4double ScreenRSquare[100];
179 static G4double FormFactor[100];
180
181 G4bool isInitialised;
182};
183
184//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
185
186inline
187void G4eCoulombScatteringModel::DefineMaterial(const G4MaterialCutsCouple* cup)
188{
189 if(cup != currentCouple) {
190 currentCouple = cup;
191 currentMaterial = cup->GetMaterial();
192 currentMaterialIndex = currentCouple->GetIndex();
193 }
194}
195
196//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
197
198inline
199void G4eCoulombScatteringModel::SetupParticle(const G4ParticleDefinition* p)
200{
201 // Initialise mass and charge
202 if(p != particle) {
203 particle = p;
204 mass = particle->GetPDGMass();
205 spin = particle->GetPDGSpin();
206 G4double q = particle->GetPDGCharge()/eplus;
207 chargeSquare = q*q;
208 tkin = 0.0;
209 }
210}
211
212//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
213
214inline void G4eCoulombScatteringModel::SetupKinematic(G4double ekin,
215 G4double cut)
216{
217 if(ekin != tkin || ecut != cut) {
218 tkin = ekin;
219 mom2 = tkin*(tkin + 2.0*mass);
220 invbeta2 = 1.0 + mass*mass/mom2;
221 cosTetMinNuc = cosThetaMin;
222 cosTetMaxNuc = cosThetaMax;
223 if(mass < MeV && cosThetaMin < 1.0 && ekin <= 10.*cut) {
224 cosTetMinNuc = ekin*(cosThetaMin + 1.0)/(10.*cut) - 1.0;
225 }
226 ComputeMaxElectronScattering(cut);
227 }
228}
229
230//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
231
232inline void G4eCoulombScatteringModel::SetupTarget(G4double Z, G4double e)
233{
234 if(Z != targetZ || e != etag) {
235 etag = e;
236 targetZ = Z;
237 iz= G4int(Z);
238 if(iz > 99) iz = 99;
239 targetMass = fNistManager->GetAtomicMassAmu(iz)*amu_c2;
240 G4double m12 = mass*mass;
241 G4double x = 1.0 + mass/targetMass;
242 kinFactor = (1.0 + m12/mom2)/mom2;
243
244 screenZ = ScreenRSquare[iz]/mom2;
245 if(iz > 1) {
246 screenZ *=(1.13 + 3.76*Z*Z*alpha2);
247 kinFactor /= (x*x);
248 }
249 // if(iz > 1) screenZ *=(1.13 + std::min(0.5,3.76*Z*Z*invbeta2*alpha2));
250 formfactA = FormFactor[iz]*mom2;
251 cosTetMaxNuc2 = cosTetMaxNuc;
252 if(1 == iz && particle == theProton && cosTetMaxNuc2 < 0.0) {
253 cosTetMaxNuc2 = 0.0;
254 }
255 cosTetMaxElec2 = cosTetMaxElec;
256 }
257}
258
259//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
260
261inline void G4eCoulombScatteringModel::SetRecoilThreshold(G4double eth)
262{
263 recoilThreshold = eth;
264}
265
266//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
267
268#endif
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