source: trunk/source/processes/electromagnetic/standard/src/G4CoulombScatteringModel.cc@ 1330

Last change on this file since 1330 was 1315, checked in by garnier, 15 years ago

update geant4-09-04-beta-cand-01 interfaces-V09-03-09 vis-V09-03-08
File size: 8.1 KB
Line 
1//
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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: G4CoulombScatteringModel.cc,v 1.49 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: G4CoulombScatteringModel
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// 19.10.06 V.Ivanchenko use inheritance from G4eCoulombScatteringModel
46// 09.10.07 V.Ivanchenko reorganized methods, add cut dependence in scattering off e-
47// 09.06.08 V.Ivanchenko SelectIsotope is moved to the base class
48// 16.06.09 Consolandi rows 109, 111-112, 183, 185-186
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 "G4CoulombScatteringModel.hh"
61#include "Randomize.hh"
62#include "G4ParticleChangeForGamma.hh"
63#include "G4ParticleTable.hh"
64#include "G4IonTable.hh"
65#include "G4Proton.hh"
66#include "G4NucleiProperties.hh"
67
68//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
69
70using namespace std;
71
72G4CoulombScatteringModel::G4CoulombScatteringModel(const G4String& nam)
73 : G4eCoulombScatteringModel(nam)
74{}
75
76//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
77
78G4CoulombScatteringModel::~G4CoulombScatteringModel()
79{}
80
81//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
82
83G4double G4CoulombScatteringModel::ComputeCrossSectionPerAtom(
84 const G4ParticleDefinition* p,
85 G4double kinEnergy,
86 G4double Z,
87 G4double,
88 G4double cutEnergy,
89 G4double)
90{
91 //G4cout << "### G4CoulombScatteringModel::ComputeCrossSectionPerAtom for "
92 // << p->GetParticleName()<<" Z= "<<Z<<" e(MeV)= "<< kinEnergy/MeV
93 // <<" cut(MeV)= " << cutEnergy<< G4endl;
94 G4double xsec = 0.0;
95 if(p != particle) { SetupParticle(p); }
96 if(kinEnergy < lowEnergyLimit) { return 0.0; }
97 DefineMaterial(CurrentCouple());
98
99 // Lab system
100 G4int iz = G4int(Z);
101 G4double etot = kinEnergy + mass;
102 G4double m2 = fNistManager->GetAtomicMassAmu(iz)*amu_c2;
103
104 // 03.09.2009 C.Consaldi suggested to use relativistic reduced mass
105 // from publucation
106 // A.P. Martynenko, R.N. Faustov, Teoret. mat. Fiz. 64 (1985) 179
107 G4double Ecm = sqrt(mass*mass + m2*m2 + 2.0*etot*m2);
108 G4double mu_rel = mass*m2/Ecm;
109 G4double tkin = Ecm - mu_rel;
110 wokvi->SetRelativisticMass(mu_rel);
111
112 cosTetMinNuc = wokvi->SetupKinematic(tkin, currentMaterial);
113 if(cosThetaMax < cosTetMinNuc) {
114 cosTetMinNuc = wokvi->SetupTarget(iz, cutEnergy);
115 cosTetMaxNuc = cosThetaMax;
116 if(iz == 1 && cosTetMaxNuc < 0.0 && particle == theProton) {
117 cosTetMaxNuc = 0.0;
118 }
119 xsec = wokvi->ComputeNuclearCrossSection(cosTetMinNuc, cosTetMaxNuc);
120 elecRatio = wokvi->ComputeElectronCrossSection(cosTetMinNuc, cosThetaMax);
121 xsec += elecRatio;
122 if(xsec > 0.0) { elecRatio /= xsec; }
123 }
124 /*
125 G4cout << "e(MeV)= " << kinEnergy/MeV << " xsec(b)= " << xsec/barn
126 << "cosTetMinNuc= " << cosTetMinNuc
127 << " cosTetMaxNuc= " << cosTetMaxNuc
128 << " cosTetMaxElec= " << cosTetMaxElec
129 << " screenZ= " << screenZ
130 << " formfactA= " << formfactA << G4endl;
131 */
132 return xsec;
133}
134
135//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
136
137void G4CoulombScatteringModel::SampleSecondaries(
138 std::vector<G4DynamicParticle*>* fvect,
139 const G4MaterialCutsCouple* couple,
140 const G4DynamicParticle* dp,
141 G4double cutEnergy,
142 G4double)
143{
144 G4double kinEnergy = dp->GetKineticEnergy();
145 if(kinEnergy < lowEnergyLimit) { return; }
146 DefineMaterial(couple);
147 SetupParticle(dp->GetDefinition());
148
149 // Choose nucleus
150 currentElement = SelectRandomAtom(couple,particle,
151 kinEnergy,cutEnergy,kinEnergy);
152
153 G4double Z = currentElement->GetZ();
154 G4int iz = G4int(Z);
155 G4int ia = SelectIsotopeNumber(currentElement);
156 G4double targetMass = G4NucleiProperties::GetNuclearMass(ia, iz);
157
158 if(ComputeCrossSectionPerAtom(particle,kinEnergy, Z,
159 kinEnergy, cutEnergy, kinEnergy) == 0.0)
160 { return; }
161
162 G4ThreeVector newDirection =
163 wokvi->SampleSingleScattering(cosTetMinNuc, cosTetMaxNuc, elecRatio);
164
165 // kinematics in the Lab system
166 G4double etot = mass + kinEnergy;
167 G4double ptot = sqrt(kinEnergy*(etot + mass));
168 G4double bet = ptot/(etot + targetMass);
169 G4double gam = 1.0/sqrt((1.0 - bet)*(1.0 + bet));
170 G4double eCM = sqrt(mass*mass + targetMass*targetMass + 2*targetMass*etot);
171 G4double pCM = ptot*targetMass/eCM;
172 G4double e1 = sqrt(mass*mass + pCM*pCM);
173
174 newDirection *= pCM;
175
176 G4ThreeVector v1(newDirection.x(),newDirection.y(),gam*(newDirection.z() + bet*e1));
177 G4double finalT = gam*(e1 + bet*newDirection.z()) - mass;
178 newDirection = v1.unit();
179
180 G4ThreeVector dir = dp->GetMomentumDirection();
181 newDirection.rotateUz(dir);
182 fParticleChange->ProposeMomentumDirection(newDirection);
183
184 // recoil
185 G4double trec = kinEnergy - finalT;
186 if(finalT <= lowEnergyLimit) {
187 trec = kinEnergy;
188 finalT = 0.0;
189 }
190
191 fParticleChange->SetProposedKineticEnergy(finalT);
192
193 // G4cout << "sint= " << sint << " Erec(eV)= " << erec/eV << G4endl;
194
195 G4double tcut = recoilThreshold;
196 if(pCuts) { tcut= std::max(tcut,(*pCuts)[currentMaterialIndex]); }
197 /*
198 G4cout << "sint= " << sint << " Erec(eV)= " << erec/eV
199 << " tcut(eV)= " << tcut/eV << " th(eV)= " << recoilThreshold/eV
200 << " cut(eV)= " << (*pCuts)[currentMaterialIndex]/eV
201 << " " << fvect->size()
202 << G4endl;
203 */
204 if(trec > tcut) {
205 G4ParticleDefinition* ion = theParticleTable->FindIon(iz, ia, 0, iz);
206 G4double plab = sqrt(finalT*(finalT + 2.0*mass));
207 G4ThreeVector p2 = (ptot*dir - plab*newDirection).unit();
208 G4DynamicParticle* newdp = new G4DynamicParticle(ion, p2, trec);
209 fvect->push_back(newdp);
210 } else if(trec > 0.0) {
211 fParticleChange->ProposeLocalEnergyDeposit(trec);
212 fParticleChange->ProposeNonIonizingEnergyDeposit(trec);
213 }
214}
215
216//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
217
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