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25 //
26 /// \file medical/fanoCavity/src/MyKleinNishin
27 /// \brief Implementation of the MyKleinNishin
28 //
29 //
30 //....oooOO0OOooo........oooOO0OOooo........oo
31 //....oooOO0OOooo........oooOO0OOooo........oo
32
33 #include "MyKleinNishinaCompton.hh"
34
35 #include "DetectorConstruction.hh"
36 #include "MyKleinNishinaMessenger.hh"
37
38 #include "G4DataVector.hh"
39 #include "G4Electron.hh"
40 #include "G4Gamma.hh"
41 #include "G4ParticleChangeForGamma.hh"
42 #include "G4PhysicalConstants.hh"
43 #include "Randomize.hh"
44
45 //....oooOO0OOooo........oooOO0OOooo........oo
46
47 using namespace std;
48
49 MyKleinNishinaCompton::MyKleinNishinaCompton(D
50 c
51 : G4KleinNishinaCompton(0, nam), fDetector(d
52 {
53 fCrossSectionFactor = 1.;
54 fMessenger = new MyKleinNishinaMessenger(thi
55 }
56
57 //....oooOO0OOooo........oooOO0OOooo........oo
58
59 MyKleinNishinaCompton::~MyKleinNishinaCompton(
60 {
61 delete fMessenger;
62 }
63
64 //....oooOO0OOooo........oooOO0OOooo........oo
65
66 G4double MyKleinNishinaCompton::CrossSectionPe
67
68
69 {
70 G4double xsection = G4VEmModel::CrossSection
71
72 return xsection * fCrossSectionFactor;
73 }
74 //....oooOO0OOooo........oooOO0OOooo........oo
75
76 void MyKleinNishinaCompton::SampleSecondaries(
77
78
79
80 {
81 // The scattered gamma energy is sampled acc
82 // The random number techniques of Butcher &
83 // (Nuc Phys 20(1960),15).
84 // Note : Effects due to binding of atomic e
85
86 G4double gamEnergy0 = aDynamicGamma->GetKine
87 G4double E0_m = gamEnergy0 / electron_mass_c
88
89 G4ThreeVector gamDirection0 = aDynamicGamma-
90
91 //
92 // sample the energy rate of the scattered g
93 //
94
95 G4double epsilon, epsilonsq, onecost, sint2,
96
97 G4double eps0 = 1. / (1. + 2. * E0_m);
98 G4double eps0sq = eps0 * eps0;
99 G4double alpha1 = -log(eps0);
100 G4double alpha2 = 0.5 * (1. - eps0sq);
101
102 do {
103 if (alpha1 / (alpha1 + alpha2) > G4Uniform
104 epsilon = exp(-alpha1 * G4UniformRand())
105 epsilonsq = epsilon * epsilon;
106 }
107 else {
108 epsilonsq = eps0sq + (1. - eps0sq) * G4U
109 epsilon = sqrt(epsilonsq);
110 };
111
112 onecost = (1. - epsilon) / (epsilon * E0_m
113 sint2 = onecost * (2. - onecost);
114 greject = 1. - epsilon * sint2 / (1. + eps
115
116 } while (greject < G4UniformRand());
117
118 //
119 // scattered gamma angles. ( Z - axis along
120 //
121
122 G4double cosTeta = 1. - onecost;
123 G4double sinTeta = sqrt(sint2);
124 G4double Phi = twopi * G4UniformRand();
125 G4double dirx = sinTeta * cos(Phi), diry = s
126
127 //
128 // update G4VParticleChange for the scattere
129 //
130 // beam regeneration trick : restore inciden
131
132 G4ThreeVector gamDirection1(dirx, diry, dirz
133 gamDirection1.rotateUz(gamDirection0);
134 G4double gamEnergy1 = epsilon * gamEnergy0;
135 fParticleChange->SetProposedKineticEnergy(ga
136 fParticleChange->ProposeMomentumDirection(ga
137
138 //
139 // kinematic of the scattered electron
140 //
141
142 G4double eKinEnergy = gamEnergy0 - gamEnergy
143
144 if (eKinEnergy > DBL_MIN) {
145 G4ThreeVector eDirection = gamEnergy0 * ga
146 eDirection = eDirection.unit();
147
148 // create G4DynamicParticle object for the
149 G4DynamicParticle* dp = new G4DynamicParti
150 fvect->push_back(dp);
151 }
152 }
153
154 //....oooOO0OOooo........oooOO0OOooo........oo
155