source: trunk/source/processes/electromagnetic/standard/src/G4eCoulombScatteringModel.cc @ 1316

Last change on this file since 1316 was 1315, checked in by garnier, 14 years ago

update geant4-09-04-beta-cand-01 interfaces-V09-03-09 vis-V09-03-08
File size: 8.8 KB
Line 
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26// $Id: G4eCoulombScatteringModel.cc,v 1.89 2010/05/27 14:22:05 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-04-beta-cand-01 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name:     G4eCoulombScatteringModel
35//
36// Author:        Vladimir Ivanchenko
37//
38// Creation date: 22.08.2005
39//
40// Modifications:
41//
42// 01.08.06 V.Ivanchenko extend upper limit of table to TeV and review the
43//          logic of building - only elements from G4ElementTable
44// 08.08.06 V.Ivanchenko build internal table in ekin scale, introduce faclim
45// 19.08.06 V.Ivanchenko add inline function ScreeningParameter
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// 16.06.09 C.Consolandi fixed computation of effective mass
49// 27.05.10 V.Ivanchenko added G4WentzelOKandVIxSection class to
50//              compute cross sections and sample scattering angle
51//
52//
53// Class Description:
54//
55// -------------------------------------------------------------------
56//
57//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
58//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
59
60#include "G4eCoulombScatteringModel.hh"
61#include "Randomize.hh"
62#include "G4DataVector.hh"
63#include "G4ElementTable.hh"
64#include "G4ParticleChangeForGamma.hh"
65#include "G4Proton.hh"
66#include "G4ParticleTable.hh"
67#include "G4ProductionCutsTable.hh"
68#include "G4NucleiProperties.hh"
69#include "G4Pow.hh"
70#include "G4LossTableManager.hh"
71#include "G4NistManager.hh"
72
73//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
74
75using namespace std;
76
77G4eCoulombScatteringModel::G4eCoulombScatteringModel(const G4String& nam)
78  : G4VEmModel(nam),
79    cosThetaMin(1.0),
80    cosThetaMax(-1.0),
81    isInitialised(false)
82{
83  fNistManager = G4NistManager::Instance();
84  theParticleTable = G4ParticleTable::GetParticleTable();
85  theProton   = G4Proton::Proton();
86  currentMaterial = 0; 
87  currentElement  = 0;
88  lowEnergyLimit  = 1*eV;
89  recoilThreshold = 0.*keV;
90  particle = 0;
91  currentCouple = 0;
92  wokvi = new G4WentzelOKandVIxSection();
93}
94
95//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
96
97G4eCoulombScatteringModel::~G4eCoulombScatteringModel()
98{
99  delete wokvi;
100}
101
102//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
103
104void G4eCoulombScatteringModel::Initialise(const G4ParticleDefinition* p,
105                                           const G4DataVector& cuts)
106{
107  SetupParticle(p);
108  currentCouple = 0;
109  cosThetaMin = cos(PolarAngleLimit());
110  wokvi->Initialise(p, cosThetaMin);
111  /*
112  G4cout << "G4eCoulombScatteringModel: factorA2(GeV^2) = " << factorA2/(GeV*GeV)
113         << "  1-cos(ThetaLimit)= " << 1 - cosThetaMin
114         << "  cos(thetaMax)= " <<  cosThetaMax
115         << G4endl;
116  */
117  pCuts = G4ProductionCutsTable::GetProductionCutsTable()->GetEnergyCutsVector(3);
118  //G4cout << "!!! G4eCoulombScatteringModel::Initialise for "
119  //     << p->GetParticleName() << "  cos(TetMin)= " << cosThetaMin
120  //     << "  cos(TetMax)= " << cosThetaMax <<G4endl;
121  // G4cout << "cut0= " << cuts[0] << "  cut1= " << cuts[1] << G4endl;
122  if(!isInitialised) {
123    isInitialised = true;
124    fParticleChange = GetParticleChangeForGamma();
125  }
126  if(mass < GeV && particle->GetParticleType() != "nucleus") {
127    InitialiseElementSelectors(p,cuts);
128  }
129}
130
131//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
132
133G4double G4eCoulombScatteringModel::ComputeCrossSectionPerAtom(
134                const G4ParticleDefinition* p,
135                G4double kinEnergy,
136                G4double Z, G4double,
137                G4double cutEnergy, G4double)
138{
139  //G4cout << "### G4eCoulombScatteringModel::ComputeCrossSectionPerAtom  for "
140  //  << p->GetParticleName()<<" Z= "<<Z<<" e(MeV)= "<< kinEnergy/MeV << G4endl;
141  G4double xsec = 0.0;
142  if(p != particle) { SetupParticle(p); }
143
144  // cross section is set to zero to avoid problems in sample secondary
145  if(kinEnergy < lowEnergyLimit) { return xsec; }
146  DefineMaterial(CurrentCouple());
147  cosTetMinNuc = wokvi->SetupKinematic(kinEnergy, currentMaterial);
148  if(cosThetaMax < cosTetMinNuc) {
149    G4int iz = G4int(Z);
150    cosTetMinNuc = wokvi->SetupTarget(iz, cutEnergy);
151    cosTetMaxNuc = cosThetaMax; 
152    if(iz == 1 && cosTetMaxNuc < 0.0 && particle == theProton) { 
153      cosTetMaxNuc = 0.0; 
154    }
155    xsec =  wokvi->ComputeNuclearCrossSection(cosTetMinNuc, cosTetMaxNuc);
156    elecRatio = wokvi->ComputeElectronCrossSection(cosTetMinNuc, cosThetaMax);
157    xsec += elecRatio;
158    if(xsec > 0.0) { elecRatio /= xsec; } 
159  }
160  /*
161  G4cout << "e(MeV)= " << kinEnergy/MeV << " xsec(b)= " << xsec/barn 
162         << " 1-cosTetMinNuc= " << 1-cosTetMinNuc
163         << " 1-cosTetMaxNuc2= " << 1-cosTetMaxNuc2
164         << " 1-cosTetMaxElec= " << 1-cosTetMaxElec
165         << " screenZ= " << screenZ
166         << " formfactA= " << formfactA << G4endl;
167  */
168  return xsec; 
169}
170
171//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
172
173void G4eCoulombScatteringModel::SampleSecondaries(
174                std::vector<G4DynamicParticle*>* fvect,
175                const G4MaterialCutsCouple* couple,
176                const G4DynamicParticle* dp,
177                G4double cutEnergy,
178                G4double)
179{
180  G4double kinEnergy = dp->GetKineticEnergy();
181  if(kinEnergy < lowEnergyLimit) { return; }
182  SetupParticle(dp->GetDefinition());
183
184  //G4cout << "G4eCoulombScatteringModel::SampleSecondaries e(MeV)= "
185  //     << kinEnergy << "  " << particle->GetParticleName()
186  //     << " cut= " << cutEnergy<< G4endl;
187 
188  // Choose nucleus
189  currentElement = SelectRandomAtom(couple,particle,
190                                    kinEnergy,cutEnergy,kinEnergy);
191
192  G4double Z = currentElement->GetZ();
193 
194  if(ComputeCrossSectionPerAtom(particle,kinEnergy, Z,
195                                kinEnergy, cutEnergy, kinEnergy) == 0.0) 
196    { return; }
197
198  G4int iz = G4int(Z);
199  G4int ia = SelectIsotopeNumber(currentElement);
200  G4double targetMass = G4NucleiProperties::GetNuclearMass(ia, iz);
201
202  G4ThreeVector newDirection = 
203    wokvi->SampleSingleScattering(cosTetMinNuc, cosThetaMax, elecRatio);
204  G4double cost = newDirection.z();
205
206  G4ThreeVector direction = dp->GetMomentumDirection(); 
207  newDirection.rotateUz(direction);   
208
209  fParticleChange->ProposeMomentumDirection(newDirection);   
210
211  // recoil sampling assuming a small recoil
212  // and first order correction to primary 4-momentum
213  G4double mom2 = wokvi->GetMomentumSquare();
214  G4double trec = mom2*(1.0 - cost)/(targetMass + (mass + kinEnergy)*(1.0 + cost));
215  G4double finalT = kinEnergy - trec; 
216  //G4cout<<"G4eCoulombScatteringModel: finalT= "<<finalT<<" Trec= "<<trec<<G4endl;
217  if(finalT <= lowEnergyLimit) { 
218    trec = kinEnergy; 
219    finalT = 0.0;
220  } 
221
222  fParticleChange->SetProposedKineticEnergy(finalT);
223  G4double tcut = recoilThreshold;
224  if(pCuts) { tcut= std::max(tcut,(*pCuts)[currentMaterialIndex]); }
225
226  if(trec > tcut) {
227    G4ParticleDefinition* ion = theParticleTable->FindIon(iz, ia, 0, iz);
228    G4ThreeVector dir = (direction*sqrt(mom2) - 
229                         newDirection*sqrt(finalT*(2*mass + finalT))).unit();
230    G4DynamicParticle* newdp = new G4DynamicParticle(ion, dir, trec);
231    fvect->push_back(newdp);
232  } else {
233    fParticleChange->ProposeLocalEnergyDeposit(trec);
234    fParticleChange->ProposeNonIonizingEnergyDeposit(trec);
235  }
236 
237  return;
238}
239
240//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
241
242
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