source: trunk/source/processes/electromagnetic/standard/include/G4WentzelVIModel.hh @ 991

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26// $Id: G4WentzelVIModel.hh,v 1.7 2008/08/04 08:49:09 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-02 $
28//
29// -------------------------------------------------------------------
30//
31//
32// GEANT4 Class header file
33//
34//
35// File name:     G4WentzelVIModel
36//
37// Author:        V.Ivanchenko
38//
39// Creation date: 09.04.2008 from G4MuMscModel
40//
41// Modifications:
42//
43//
44// Class Description:
45//
46// Implementation of the model of multiple scattering based on
47// G.Wentzel, Z. Phys. 40 (1927) 590.
48// H.W.Lewis, Phys Rev 78 (1950) 526.
49// J.M. Fernandez-Varea et al., NIM B73 (1993) 447.
50// L.Urban, CERN-OPEN-2006-077.
51
52// -------------------------------------------------------------------
53//
54
55#ifndef G4WentzelVIModel_h
56#define G4WentzelVIModel_h 1
57
58//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
59
60#include "G4VMscModel.hh"
61#include "G4PhysicsTable.hh"
62#include "G4MscStepLimitType.hh"
63#include "G4MaterialCutsCouple.hh"
64#include "G4NistManager.hh"
65
66class G4LossTableManager;
67class G4ParticleChangeForMSC;
68class G4SafetyHelper;
69class G4ParticleDefinition;
70
71//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
72
73class G4WentzelVIModel : public G4VMscModel
74{
75
76public:
77
78  G4WentzelVIModel(const G4String& nam = "WentzelVIUni");
79
80  virtual ~G4WentzelVIModel();
81
82  void Initialise(const G4ParticleDefinition*, const G4DataVector&);
83
84  G4double ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
85                                      G4double KineticEnergy,
86                                      G4double AtomicNumber,
87                                      G4double AtomicWeight=0., 
88                                      G4double cut = DBL_MAX,
89                                      G4double emax= DBL_MAX);
90
91  void SampleScattering(const G4DynamicParticle*, G4double safety);
92
93  void SampleSecondaries(std::vector<G4DynamicParticle*>*, 
94                         const G4MaterialCutsCouple*,
95                         const G4DynamicParticle*,
96                         G4double,
97                         G4double);
98
99  G4double ComputeTruePathLengthLimit(const G4Track& track,
100                                      G4PhysicsTable* theLambdaTable,
101                                      G4double currentMinimalStep);
102
103  G4double ComputeGeomPathLength(G4double truePathLength);
104
105  G4double ComputeTrueStepLength(G4double geomStepLength);
106
107private:
108
109  G4double ComputeTransportXSectionPerVolume();
110
111  G4double ComputeXSectionPerVolume();
112
113  void ComputeMaxElectronScattering(G4double cut);
114
115  inline G4double GetLambda(G4double kinEnergy);
116
117  inline void SetupParticle(const G4ParticleDefinition*);
118
119  inline void SetupKinematic(G4double kinEnergy, G4double cut);
120 
121  inline void SetupTarget(G4double Z, G4double kinEnergy);
122
123  inline void DefineMaterial(const G4MaterialCutsCouple*);
124
125  //  hide assignment operator
126  G4WentzelVIModel & operator=(const  G4WentzelVIModel &right);
127  G4WentzelVIModel(const  G4WentzelVIModel&);
128
129  const G4ParticleDefinition* theProton;
130  const G4ParticleDefinition* theElectron;
131  const G4ParticleDefinition* thePositron;
132
133  G4ParticleChangeForMSC*   fParticleChange;
134
135  G4SafetyHelper*           safetyHelper;
136  G4PhysicsTable*           theLambdaTable;
137  G4PhysicsTable*           theLambda2Table;
138  G4LossTableManager*       theManager;
139  const G4DataVector*       currentCuts;
140
141  G4NistManager*            fNistManager;
142
143  G4double numlimit;
144  G4double tlimitminfix;
145  G4double invsqrt12;
146
147  // cash
148  G4double preKinEnergy;
149  G4double ecut;
150  G4double lambda0;
151  G4double tPathLength;
152  G4double zPathLength;
153  G4double lambdaeff;
154  G4double currentRange; 
155  G4double par1;
156  G4double par2;
157  G4double par3;
158
159  G4double xtsec;
160  std::vector<G4double> xsecn;
161  std::vector<G4double> prob;
162  G4int    nelments;
163
164  G4int    nbins;
165  G4int    nwarnings;
166  G4int    nwarnlimit;
167
168  G4int    currentMaterialIndex;
169
170  const G4MaterialCutsCouple* currentCouple;
171  const G4Material* currentMaterial;
172
173  // single scattering parameters
174  G4double coeff;
175  G4double constn;
176  G4double cosThetaMin;
177  G4double cosThetaMax;
178  G4double cosTetMaxNuc;
179  G4double cosTetMaxNuc2;
180  G4double cosTetMaxElec;
181  G4double cosTetMaxElec2;
182  G4double q2Limit;
183  G4double alpha2;
184  G4double a0;
185
186  // projectile
187  const G4ParticleDefinition* particle;
188
189  G4double chargeSquare;
190  G4double spin;
191  G4double mass;
192  G4double tkin;
193  G4double mom2;
194  G4double invbeta2;
195  G4double etag;
196  G4double lowEnergyLimit;
197
198  // target
199  G4double targetZ;
200  G4double screenZ;
201  G4double formfactA;
202  G4double FF[100];
203
204  // flags
205  G4bool   isInitialized;
206  G4bool   inside;
207};
208
209//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
210//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
211
212inline
213void G4WentzelVIModel::DefineMaterial(const G4MaterialCutsCouple* cup) 
214{ 
215  if(cup != currentCouple) {
216    currentCouple = cup;
217    currentMaterial = cup->GetMaterial();
218    currentMaterialIndex = currentCouple->GetIndex(); 
219  }
220}
221
222//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
223
224inline
225G4double G4WentzelVIModel::GetLambda(G4double e)
226{
227  G4double x;
228  if(theLambdaTable) {
229    G4bool b;
230    x = ((*theLambdaTable)[currentMaterialIndex])->GetValue(e, b);
231  } else {
232    x = CrossSection(currentCouple,particle,e,
233                     (*currentCuts)[currentMaterialIndex]);
234  }
235  if(x > DBL_MIN) x = 1./x;
236  else            x = DBL_MAX;
237  return x;
238}
239
240//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
241
242inline 
243void G4WentzelVIModel::SetupParticle(const G4ParticleDefinition* p)
244{
245  // Initialise mass and charge
246  if(p != particle) {
247    particle = p;
248    mass = particle->GetPDGMass();
249    spin = particle->GetPDGSpin();
250    G4double q = particle->GetPDGCharge()/eplus;
251    chargeSquare = q*q;
252    tkin = 0.0;
253    lowEnergyLimit = keV*mass/electron_mass_c2;
254  }
255}
256
257//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
258
259inline void G4WentzelVIModel::SetupKinematic(G4double ekin, G4double cut)
260{
261  if(ekin != tkin || ecut != cut) {
262    tkin  = ekin;
263    mom2  = tkin*(tkin + 2.0*mass);
264    invbeta2 = 1.0 +  mass*mass/mom2;
265    cosTetMaxNuc = cosThetaMax;
266    if(ekin <= 10.*cut && mass < MeV) {
267      cosTetMaxNuc = ekin*(cosThetaMax + 1.0)/(10.*cut) - 1.0;
268    }
269    ComputeMaxElectronScattering(cut);
270  } 
271}
272
273//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
274 
275inline void G4WentzelVIModel::SetupTarget(G4double Z, G4double e)
276{
277  if(Z != targetZ || e != etag) {
278    etag    = e; 
279    targetZ = Z;
280    G4int iz= G4int(Z);
281    if(iz > 99) iz = 99;
282    G4double x = fNistManager->GetZ13(iz);
283    screenZ = a0*x*x/mom2;
284    if(iz > 1) screenZ *=(1.13 + 3.76*invbeta2*Z*Z*chargeSquare*alpha2);
285    //    screenZ = a0*x*x*(1.13 + 3.76*Z*Z*chargeSquare*alpha2)/mom2;
286    // A.V. Butkevich et al., NIM A 488 (2002) 282
287    formfactA = FF[iz];
288    if(formfactA == 0.0) {
289      x = fNistManager->GetA27(iz); 
290      formfactA = constn*x*x;
291      FF[iz] = formfactA;
292    }
293    formfactA *= mom2;
294    cosTetMaxNuc2 = cosTetMaxNuc;
295    /*
296    G4double ee = 10.*eV*Z;
297    if(1 == iz) ee *= 2.0;
298    G4double z = std::min(cosTetMaxElec, 1.0 - std::max(ecut,ee)*amu_c2
299                          *fNistManager->GetAtomicMassAmu(iz)/mom2);
300    cosTetMaxElec2 = std::max(cosTetMaxNuc2, z);
301    */
302    cosTetMaxElec2 = cosTetMaxElec;
303  } 
304} 
305
306//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
307
308#endif
309
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