source: trunk/source/processes/electromagnetic/standard/src/G4PEEffectModel.cc@ 1042

Last change on this file since 1042 was 1007, checked in by garnier, 17 years ago

update to geant4.9.2
File size: 6.0 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 1.6 2007/05/22 17:34:36 vnivanch Exp $
27// GEANT4 tag $Name: geant4-09-02 $
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//
44// Class Description:
45//
46// -------------------------------------------------------------------
47//
48//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
49//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
50
51#include "G4PEEffectModel.hh"
52#include "G4Electron.hh"
53#include "G4Gamma.hh"
54#include "Randomize.hh"
55#include "G4DataVector.hh"
56#include "G4ParticleChangeForGamma.hh"
57
58//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
59
60using namespace std;
61
62G4PEEffectModel::G4PEEffectModel(const G4ParticleDefinition*,
63 const G4String& nam)
64 : G4VEmModel(nam),isInitialized(false)
65{
66 theGamma = G4Gamma::Gamma();
67 theElectron = G4Electron::Electron();
68}
69
70//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
71
72G4PEEffectModel::~G4PEEffectModel()
73{
74}
75
76//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
77
78void G4PEEffectModel::Initialise(const G4ParticleDefinition*,
79 const G4DataVector&)
80{
81 if (isInitialized) return;
82 if (pParticleChange)
83 fParticleChange =
84 reinterpret_cast<G4ParticleChangeForGamma*>(pParticleChange);
85 else
86 fParticleChange = new G4ParticleChangeForGamma();
87
88 fminimalEnergy = 1.0*eV;
89}
90
91//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
92
93void G4PEEffectModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
94 const G4MaterialCutsCouple* couple,
95 const G4DynamicParticle* aDynamicPhoton,
96 G4double,
97 G4double)
98{
99 const G4Material* aMaterial = couple->GetMaterial();
100
101 G4double energy = aDynamicPhoton->GetKineticEnergy();
102 G4ParticleMomentum PhotonDirection = aDynamicPhoton->GetMomentumDirection();
103
104 // select randomly one element constituing the material.
105 const G4Element* anElement = SelectRandomAtom(aMaterial,theGamma,energy);
106
107 //
108 // Photo electron
109 //
110
111 // Select atomic shell
112 G4int nShells = anElement->GetNbOfAtomicShells();
113 G4int i = 0;
114 while ((i<nShells) && (energy<anElement->GetAtomicShell(i))) i++;
115
116 // no shell available
117 if (i == nShells) return;
118
119 G4double bindingEnergy = anElement->GetAtomicShell(i);
120 G4double ElecKineEnergy = energy - bindingEnergy;
121
122 if (ElecKineEnergy > fminimalEnergy)
123 {
124 // direction of the photo electron
125 //
126 G4double cosTeta = ElecCosThetaDistribution(ElecKineEnergy);
127 G4double sinTeta = sqrt(1.-cosTeta*cosTeta);
128 G4double Phi = twopi * G4UniformRand();
129 G4double dirx = sinTeta*cos(Phi),diry = sinTeta*sin(Phi),dirz = cosTeta;
130 G4ThreeVector ElecDirection(dirx,diry,dirz);
131 ElecDirection.rotateUz(PhotonDirection);
132 //
133 G4DynamicParticle* aParticle = new G4DynamicParticle (
134 theElectron,ElecDirection, ElecKineEnergy);
135 fvect->push_back(aParticle);
136 }
137
138 fParticleChange->SetProposedKineticEnergy(0.);
139 fParticleChange->ProposeTrackStatus(fStopAndKill);
140 fParticleChange->ProposeLocalEnergyDeposit(bindingEnergy);
141}
142
143//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
144
145G4double G4PEEffectModel::ElecCosThetaDistribution(G4double kineEnergy)
146{
147 // Compute Theta distribution of the emitted electron, with respect to the
148 // incident Gamma.
149 // The Sauter-Gavrila distribution for the K-shell is used.
150 //
151 G4double costeta = 1.;
152 G4double gamma = 1. + kineEnergy/electron_mass_c2;
153 if (gamma > 5.) return costeta;
154 G4double beta = sqrt(gamma*gamma-1.)/gamma;
155 G4double b = 0.5*gamma*(gamma-1.)*(gamma-2);
156
157 G4double rndm,term,greject,grejsup;
158 if (gamma < 2.) grejsup = gamma*gamma*(1.+b-beta*b);
159 else grejsup = gamma*gamma*(1.+b+beta*b);
160
161 do { rndm = 1.-2*G4UniformRand();
162 costeta = (rndm+beta)/(rndm*beta+1.);
163 term = 1.-beta*costeta;
164 greject = (1.-costeta*costeta)*(1.+b*term)/(term*term);
165 } while(greject < G4UniformRand()*grejsup);
166
167 return costeta;
168}
169
170//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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