| Geant4 Cross Reference |
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 //
27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class header file
30 //
31 //
32 // File name: G4eDPWACoulombScatteringModel
33 //
34 // Author: Mihaly Novak
35 //
36 // Creation date: 02.07.2020
37 //
38 // Modifications:
39 //
40 // -------------------------------------------------------------------
41
42 #include "G4eDPWACoulombScatteringModel.hh"
43
44 #include "G4eDPWAElasticDCS.hh"
45 #include "G4ParticleChangeForGamma.hh"
46 #include "G4ParticleDefinition.hh"
47 #include "G4DataVector.hh"
48
49 #include "G4ProductionCutsTable.hh"
50 #include "G4Material.hh"
51 #include "G4Element.hh"
52 #include "G4ElementVector.hh"
53
54 #include "G4Electron.hh"
55
56 #include "G4PhysicalConstants.hh"
57 #include "G4SystemOfUnits.hh"
58 #include "Randomize.hh"
59 #include "G4ThreeVector.hh"
60
61
62 G4eDPWACoulombScatteringModel::G4eDPWACoulombScatteringModel(G4bool ismixed, G4bool isscpcor, G4double mumin)
63 : G4VEmModel("eDPWACoulombScattering"),
64 fIsMixedModel(ismixed),
65 fIsScpCorrection(isscpcor),
66 fMuMin(mumin),
67 fTheDCS(nullptr),
68 fParticleChange(nullptr)
69 {
70 SetLowEnergyLimit ( 0.0*CLHEP::eV); // ekin = 10 eV is used if (E< 10 eV)
71 SetHighEnergyLimit(100.0*CLHEP::MeV); // ekin = 100 MeV is used if (E>100 MeV)
72 }
73
74
75 G4eDPWACoulombScatteringModel::~G4eDPWACoulombScatteringModel()
76 {
77 if (IsMaster()) {
78 delete fTheDCS;
79 }
80 }
81
82
83 void G4eDPWACoulombScatteringModel::Initialise(const G4ParticleDefinition* pdef,
84 const G4DataVector& prodcuts)
85 {
86 if(!fParticleChange) {
87 fParticleChange = GetParticleChangeForGamma();
88 }
89 fMuMin = 0.5*(1.0-std::cos(PolarAngleLimit()));
90 fIsMixedModel = (fMuMin > 0.0);
91 if(IsMaster()) {
92 // clean the G4eDPWAElasticDCS object if any
93 delete fTheDCS;
94 fTheDCS = new G4eDPWAElasticDCS(pdef==G4Electron::Electron(), fIsMixedModel);
95 // init only for the elements that are used in the geometry
96 G4ProductionCutsTable* theCpTable = G4ProductionCutsTable::GetProductionCutsTable();
97 G4int numOfCouples = (G4int)theCpTable->GetTableSize();
98 for(G4int j=0; j<numOfCouples; ++j) {
99 const G4Material* mat = theCpTable->GetMaterialCutsCouple(j)->GetMaterial();
100 const G4ElementVector* elV = mat->GetElementVector();
101 std::size_t numOfElem = mat->GetNumberOfElements();
102 for (std::size_t ie = 0; ie < numOfElem; ++ie) {
103 fTheDCS->InitialiseForZ((*elV)[ie]->GetZasInt());
104 }
105 }
106 // init scattering power correction
107 if (fIsScpCorrection) {
108 fTheDCS->InitSCPCorrection(LowEnergyLimit(), HighEnergyLimit());
109 }
110 // will make use of the cross sections so the above needs to be done before
111 InitialiseElementSelectors(pdef, prodcuts);
112 }
113 }
114
115
116 void G4eDPWACoulombScatteringModel::InitialiseLocal(const G4ParticleDefinition*,
117 G4VEmModel* masterModel)
118 {
119 SetElementSelectors(masterModel->GetElementSelectors());
120 SetTheDCS(static_cast<G4eDPWACoulombScatteringModel*>(masterModel)->GetTheDCS());
121 }
122
123
124 G4double
125 G4eDPWACoulombScatteringModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
126 G4double ekin,
127 G4double Z,
128 G4double /*A*/,
129 G4double /*prodcut*/,
130 G4double /*emax*/)
131 {
132 // Cross sections are computed by numerical integration of the pre-computed
133 // DCS data between the muMin, muMax limits where mu(theta)=0.5[1-cos(theta)].
134 // In case of single scattering model (i.e. when fMuMin=0): [muMin=0, muMax=1]
135 // In case of mixed simulation model (i.e. when fMuMin>0): [fMuMin , muMax=1]
136 // NOTE: cross sections will be zero if the kinetic enrgy is out of the
137 // [10 eV-100 MeV] range for which DCS data has been computed.
138 //
139 G4double elCS = 0.0; // elastic cross section
140 G4double tr1CS = 0.0; // first transport cross section
141 G4double tr2CS = 0.0; // second transport cross section
142 const G4double muMin = fMuMin;
143 const G4double muMax = 1.0;
144 fTheDCS->ComputeCSPerAtom((G4int)Z, ekin, elCS, tr1CS, tr2CS, muMin, muMax);
145 // scattering power correction: should be only in condensed history ioni!
146 if (fIsScpCorrection && CurrentCouple()) {
147 const G4double theScpCor = fTheDCS->ComputeScatteringPowerCorrection(CurrentCouple(), ekin);
148 elCS *= (theScpCor*(1.0+1.0/Z));
149 }
150 return std::max(0.0, elCS);
151 }
152
153
154 void
155 G4eDPWACoulombScatteringModel::SampleSecondaries(std::vector<G4DynamicParticle*>*,
156 const G4MaterialCutsCouple* cp,
157 const G4DynamicParticle* dp,
158 G4double, G4double)
159 {
160 const G4double ekin = dp->GetKineticEnergy();
161 const G4double lekin = dp->GetLogKineticEnergy();
162 const G4Element* target = SelectTargetAtom(cp, dp->GetParticleDefinition(), ekin, lekin);
163 const G4int izet = target->GetZasInt();
164 // sample cosine of the polar scattering angle in (hard) elastic insteraction
165 CLHEP::HepRandomEngine* rndmEngine = G4Random::getTheEngine();
166 G4double cost = 1.0;
167 if (!fIsMixedModel) {
168 G4double rndm[3];
169 rndmEngine->flatArray(3, rndm);
170 cost = fTheDCS->SampleCosineTheta(izet, lekin, rndm[0], rndm[1], rndm[2]);
171 } else {
172 //sample cost between costMax,costMin where costMax = 1-2xfMuMin;
173 const G4double costMax = 1.0-2.0*fMuMin;
174 const G4double costMin = -1.0;
175 G4double rndm[2];
176 rndmEngine->flatArray(2, rndm);
177 cost = fTheDCS->SampleCosineThetaRestricted(izet, lekin, rndm[0], rndm[1], costMin, costMax);
178 }
179 // compute the new direction in the scattering frame
180 const G4double sint = std::sqrt((1.0-cost)*(1.0+cost));
181 const G4double phi = CLHEP::twopi*rndmEngine->flat();
182 G4ThreeVector theNewDirection(sint*std::cos(phi), sint*std::sin(phi), cost);
183 // get original direction in lab frame and rotate new direction to lab frame
184 G4ThreeVector theOrgDirectionLab = dp->GetMomentumDirection();
185 theNewDirection.rotateUz(theOrgDirectionLab);
186 // set new direction
187 fParticleChange->ProposeMomentumDirection(theNewDirection);
188 }
189
190
191
192
193
194