source: trunk/source/processes/electromagnetic/standard/include/G4eCoulombScatteringModel.hh @ 985

Last change on this file since 985 was 961, checked in by garnier, 15 years ago

update processes
File size: 8.8 KB
Line 
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 *
9// * include a list of copyright holders.                             *
10// *                                                                  *
11// * Neither the authors of this software system, nor their employing *
12// * institutes,nor the agencies providing financial support for this *
13// * work  make  any representation or  warranty, express or implied, *
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 *
22// * use  in  resulting  scientific  publications,  and indicate your *
23// * acceptance of all terms of the Geant4 Software license.          *
24// ********************************************************************
25//
26// $Id: G4eCoulombScatteringModel.hh,v 1.36 2008/08/04 08:49:09 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-02-ref-02 $
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 "G4NistManager.hh"
68#include "globals.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                  constn;
140  G4double                  cosThetaMin;
141  G4double                  cosThetaMax;
142  G4double                  cosTetMinNuc;
143  G4double                  cosTetMaxNuc;
144  G4double                  cosTetMaxNuc2;
145  G4double                  cosTetMaxElec;
146  G4double                  cosTetMaxElec2;
147  G4double                  q2Limit;
148  G4double                  recoilThreshold;
149  G4double                  elecXSection;
150  G4double                  nucXSection;
151  G4double                  ecut;
152
153  // projectile
154  const G4ParticleDefinition* particle;
155
156  G4double                  chargeSquare;
157  G4double                  spin;
158  G4double                  mass;
159  G4double                  tkin;
160  G4double                  mom2;
161  G4double                  invbeta2;
162  G4double                  etag;
163  G4double                  lowEnergyLimit;
164
165  // target
166  G4double                  targetZ;
167  G4double                  screenZ;
168  G4double                  formfactA;
169  G4int                     idxelm;
170
171private:
172
173  G4double                  a0;
174  G4double                  alpha2;
175  G4double                  faclim;
176  G4double                  FF[100];
177
178  G4bool                    isInitialised;             
179};
180
181//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
182
183inline
184void G4eCoulombScatteringModel::DefineMaterial(const G4MaterialCutsCouple* cup) 
185{ 
186  if(cup != currentCouple) {
187    currentCouple = cup;
188    currentMaterial = cup->GetMaterial();
189    currentMaterialIndex = currentCouple->GetIndex(); 
190  }
191}
192
193//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
194
195inline 
196void G4eCoulombScatteringModel::SetupParticle(const G4ParticleDefinition* p)
197{
198  // Initialise mass and charge
199  if(p != particle) {
200    particle = p;
201    mass = particle->GetPDGMass();
202    spin = particle->GetPDGSpin();
203    G4double q = particle->GetPDGCharge()/eplus;
204    chargeSquare = q*q;
205    tkin = 0.0;
206    lowEnergyLimit = keV*mass/electron_mass_c2;
207  }
208}
209
210//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
211
212inline void G4eCoulombScatteringModel::SetupKinematic(G4double ekin, 
213                                                      G4double cut)
214{
215  if(ekin != tkin || ecut != cut) {
216    tkin = ekin;
217    mom2 = tkin*(tkin + 2.0*mass);
218    invbeta2 = 1.0 +  mass*mass/mom2;
219    cosTetMinNuc = cosThetaMin;
220    cosTetMaxNuc = cosThetaMax;
221    if(ekin <= 10.*cut && mass < MeV && cosThetaMin < 1.0) {
222      cosTetMinNuc = ekin*(cosThetaMin + 1.0)/(10.*cut) - 1.0;
223    }
224    ComputeMaxElectronScattering(cut);
225  }
226}
227
228//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
229 
230inline void G4eCoulombScatteringModel::SetupTarget(G4double Z, G4double e)
231{
232  if(Z != targetZ || e != etag) {
233    etag    = e; 
234    targetZ = Z;
235    G4int iz= G4int(Z);
236    if(iz > 99) iz = 99;
237    G4double x = fNistManager->GetZ13(iz);
238    screenZ = a0*x*x/mom2;
239    if(iz > 1) screenZ *=(1.13 + 3.76*invbeta2*Z*Z*chargeSquare*alpha2);
240    //screenZ = a0*x*x*(1.13 + 3.76*Z*Z*chargeSquare*alpha2)/mom2;
241    // A.V. Butkevich et al., NIM A 488 (2002) 282
242    formfactA = FF[iz];
243    if(formfactA == 0.0) {
244      x = fNistManager->GetA27(iz); 
245      formfactA = constn*x*x;
246      FF[iz] = formfactA;
247    }
248    formfactA *= mom2;
249    cosTetMaxNuc2 = cosTetMaxNuc;
250    if(particle == theProton && 1 == iz && cosTetMaxNuc2 < 0.0) {
251      cosTetMaxNuc2 = 0.0;
252    }
253    /*
254    G4double ee = 10.*eV*Z;
255    if(1 == iz) ee *= 2.0;
256    G4double z = std::min(cosTetMaxElec, 1.0 - std::max(ecut,ee)*amu_c2
257                          *fNistManager->GetAtomicMassAmu(iz)/mom2);
258    cosTetMaxElec2 = std::max(cosTetMaxNuc2, z);
259    */
260    cosTetMaxElec2 = cosTetMaxElec;
261  } 
262} 
263
264//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
265
266inline void G4eCoulombScatteringModel::SetRecoilThreshold(G4double eth)
267{
268  recoilThreshold = eth;
269}
270
271//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
272
273#endif
Note: See TracBrowser for help on using the repository browser.