Geant4  10.03
G4RDModifiedTsai.cc
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27 // -------------------------------------------------------------------
28 //
29 // GEANT4 Class file
30 //
31 //
32 // File name: G4RDModifiedTsai
33 //
34 // Author: Andreia Trindade (andreia@lip.pt)
35 // Pedro Rodrigues (psilva@lip.pt)
36 // Luis Peralta (luis@lip.pt)
37 //
38 // Creation date: 21 March 2003
39 //
40 // Modifications:
41 // 21 Mar 2003 A. Trindade First implementation acording with new design
42 // 24 Mar 2003 & Fix in Tsai generator in order to prevent theta generation above pi
43 //
44 // Class Description:
45 //
46 // Concrete base class for Bremsstrahlung Angular Distribution Generation - Tsai Model
47 //
48 // Class Description: End
49 //
50 // -------------------------------------------------------------------
51 //
52 //
53 
54 #include "G4RDModifiedTsai.hh"
55 #include "Randomize.hh"
56 #include "G4PhysicalConstants.hh"
57 //
58 
60 {;}
61 
62 //
63 
65 {;}
66 
67 //
68 
70  const G4double, // final_energy
71  const G4int ) // Z
72 {
73 
74  // Sample gamma angle (Z - axis along the parent particle).
75  // Universal distribution suggested by L. Urban (Geant3 manual (1993)
76  // Phys211) derived from Tsai distribution (Rev Mod Phys 49,421(1977))
77 
78  G4double totalEnergy = initial_energy + electron_mass_c2;
79 
80  const G4double a1 = 0.625, a2 = 3.*a1, d = 27.;
81  G4double u, theta = 0;
82 
83  do{
84  u = - std::log(G4UniformRand()*G4UniformRand());
85 
86  if (9./(9.+d) > G4UniformRand()) u /= a1;
87  else u /= a2;
88 
89  theta = u*electron_mass_c2/totalEnergy;
90  }while(u > (totalEnergy*pi/electron_mass_c2));
91 
92  return theta;
93 }
94 //
95 
97 {
98 
99  G4cout << "\n" << G4endl;
100  G4cout << "Bremsstrahlung Angular Generator is Modified Tsai" << G4endl;
101  G4cout << "Universal distribution suggested by L. Urban (Geant3 manual (1993) Phys211)" << G4endl;
102  G4cout << "Derived from Tsai distribution (Rev Mod Phys 49,421(1977)) \n" << G4endl;
103 }
G4RDModifiedTsai(const G4String &name)
const char * name(G4int ptype)
int G4int
Definition: G4Types.hh:78
#define G4UniformRand()
Definition: Randomize.hh:97
G4GLOB_DLL std::ostream G4cout
void PrintGeneratorInformation() const
#define G4endl
Definition: G4ios.hh:61
static constexpr double pi
Definition: G4SIunits.hh:75
G4double PolarAngle(const G4double initial_energy, const G4double final_energy, const G4int Z)
double G4double
Definition: G4Types.hh:76