source: trunk/source/processes/electromagnetic/standard/include/G4eCoulombScatteringModel.hh @ 1183

Last change on this file since 1183 was 1055, checked in by garnier, 15 years ago

maj sur la beta de geant 4.9.3
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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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