source: trunk/source/processes/electromagnetic/standard/src/G4PEEffectModel.cc@ 1317

Last change on this file since 1317 was 1228, checked in by garnier, 16 years ago

update geant4.9.3 tag
File size: 7.2 KB
Line 
1//
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14// * regarding this software system or assume any liability for its *
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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 *
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24// ********************************************************************
25//
26// $Id: G4PEEffectModel.cc,v 1.8 2009/04/09 18:41:18 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-03 $
28//
29// -------------------------------------------------------------------
30//
31// GEANT4 Class file
32//
33//
34// File name: G4PEEffectModel
35//
36// Author: Vladimir Ivanchenko on base of Michel Maire code
37//
38// Creation date: 21.03.2005
39//
40// Modifications:
41//
42// 04.12.05 : SetProposedKineticEnergy(0.) for the killed photon (mma)
43// 20.02.09 : Added initialisation of deexcitation flag and method
44// CrossSectionPerVolume instead of mfp (V.Ivanchenko)
45//
46// Class Description:
47//
48// -------------------------------------------------------------------
49//
50//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
51//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
52
53#include "G4PEEffectModel.hh"
54#include "G4Electron.hh"
55#include "G4Gamma.hh"
56#include "Randomize.hh"
57#include "G4DataVector.hh"
58#include "G4ParticleChangeForGamma.hh"
59
60//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
61
62using namespace std;
63
64G4PEEffectModel::G4PEEffectModel(const G4ParticleDefinition*,
65 const G4String& nam)
66 : G4VEmModel(nam),isInitialized(false)
67{
68 theGamma = G4Gamma::Gamma();
69 theElectron = G4Electron::Electron();
70 fminimalEnergy = 1.0*eV;
71}
72
73//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
74
75G4PEEffectModel::~G4PEEffectModel()
76{}
77
78//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
79
80void G4PEEffectModel::Initialise(const G4ParticleDefinition*,
81 const G4DataVector&)
82{
83 // always false before the run
84 SetDeexcitationFlag(false);
85
86 if (isInitialized) return;
87 fParticleChange = GetParticleChangeForGamma();
88 isInitialized = true;
89}
90
91//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....
92
93G4double G4PEEffectModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
94 G4double energy,
95 G4double Z, G4double,
96 G4double, G4double)
97{
98 G4double* SandiaCof = G4SandiaTable::GetSandiaCofPerAtom((G4int)Z, energy);
99
100 G4double energy2 = energy*energy;
101 G4double energy3 = energy*energy2;
102 G4double energy4 = energy2*energy2;
103
104 return SandiaCof[0]/energy + SandiaCof[1]/energy2 +
105 SandiaCof[2]/energy3 + SandiaCof[3]/energy4;
106}
107
108//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
109
110G4double G4PEEffectModel::CrossSectionPerVolume(const G4Material* material,
111 const G4ParticleDefinition*,
112 G4double energy,
113 G4double, G4double)
114{
115 G4double* SandiaCof =
116 material->GetSandiaTable()->GetSandiaCofForMaterial(energy);
117
118 G4double energy2 = energy*energy;
119 G4double energy3 = energy*energy2;
120 G4double energy4 = energy2*energy2;
121
122 return SandiaCof[0]/energy + SandiaCof[1]/energy2 +
123 SandiaCof[2]/energy3 + SandiaCof[3]/energy4;
124}
125
126//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
127
128void G4PEEffectModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
129 const G4MaterialCutsCouple* couple,
130 const G4DynamicParticle* aDynamicPhoton,
131 G4double,
132 G4double)
133{
134 const G4Material* aMaterial = couple->GetMaterial();
135
136 G4double energy = aDynamicPhoton->GetKineticEnergy();
137 G4ParticleMomentum PhotonDirection = aDynamicPhoton->GetMomentumDirection();
138
139 // select randomly one element constituing the material.
140 const G4Element* anElement = SelectRandomAtom(aMaterial,theGamma,energy);
141
142 //
143 // Photo electron
144 //
145
146 // Select atomic shell
147 G4int nShells = anElement->GetNbOfAtomicShells();
148 G4int i = 0;
149 while ((i<nShells) && (energy<anElement->GetAtomicShell(i))) i++;
150
151 // no shell available
152 if (i == nShells) return;
153
154 G4double bindingEnergy = anElement->GetAtomicShell(i);
155 G4double ElecKineEnergy = energy - bindingEnergy;
156
157 if (ElecKineEnergy > fminimalEnergy)
158 {
159 // direction of the photo electron
160 //
161 G4double cosTeta = ElecCosThetaDistribution(ElecKineEnergy);
162 G4double sinTeta = sqrt(1.-cosTeta*cosTeta);
163 G4double Phi = twopi * G4UniformRand();
164 G4double dirx = sinTeta*cos(Phi),diry = sinTeta*sin(Phi),dirz = cosTeta;
165 G4ThreeVector ElecDirection(dirx,diry,dirz);
166 ElecDirection.rotateUz(PhotonDirection);
167 //
168 G4DynamicParticle* aParticle = new G4DynamicParticle (
169 theElectron,ElecDirection, ElecKineEnergy);
170 fvect->push_back(aParticle);
171 }
172
173 fParticleChange->SetProposedKineticEnergy(0.);
174 fParticleChange->ProposeTrackStatus(fStopAndKill);
175 fParticleChange->ProposeLocalEnergyDeposit(bindingEnergy);
176}
177
178//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
179
180G4double G4PEEffectModel::ElecCosThetaDistribution(G4double kineEnergy)
181{
182 // Compute Theta distribution of the emitted electron, with respect to the
183 // incident Gamma.
184 // The Sauter-Gavrila distribution for the K-shell is used.
185 //
186 G4double costeta = 1.;
187 G4double gamma = 1. + kineEnergy/electron_mass_c2;
188 if (gamma > 5.) return costeta;
189 G4double beta = sqrt(gamma*gamma-1.)/gamma;
190 G4double b = 0.5*gamma*(gamma-1.)*(gamma-2);
191
192 G4double rndm,term,greject,grejsup;
193 if (gamma < 2.) grejsup = gamma*gamma*(1.+b-beta*b);
194 else grejsup = gamma*gamma*(1.+b+beta*b);
195
196 do { rndm = 1.-2*G4UniformRand();
197 costeta = (rndm+beta)/(rndm*beta+1.);
198 term = 1.-beta*costeta;
199 greject = (1.-costeta*costeta)*(1.+b*term)/(term*term);
200 } while(greject < G4UniformRand()*grejsup);
201
202 return costeta;
203}
204
205//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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