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27 // ------------------------------------------- 27 // -------------------------------------------------------------------
28 // 28 //
29 // GEANT4 Class file 29 // GEANT4 Class file
30 // 30 //
31 // 31 //
32 // File name: G4SauterGavrilaAngularDistri 32 // File name: G4SauterGavrilaAngularDistribution
33 // 33 //
34 // Author: Vladimir Ivanchenko using Miche 34 // Author: Vladimir Ivanchenko using Michel Maire algorithm
35 // developed for Geant3 35 // developed for Geant3
36 // 36 //
37 // Creation date: 23 July 2012 37 // Creation date: 23 July 2012
38 // 38 //
39 // Modified: 39 // Modified:
40 // 04.05.2017 Marilena Bandieramonte impleme 40 // 04.05.2017 Marilena Bandieramonte implemented Penelope 2014 algorithm
41 // ------------------------------------------- 41 // -------------------------------------------------------------------
42 // 42 //
43 43
44 #include "G4SauterGavrilaAngularDistribution.h 44 #include "G4SauterGavrilaAngularDistribution.hh"
45 #include "G4PhysicalConstants.hh" 45 #include "G4PhysicalConstants.hh"
46 #include "Randomize.hh" 46 #include "Randomize.hh"
47 47
48 G4SauterGavrilaAngularDistribution::G4SauterGa 48 G4SauterGavrilaAngularDistribution::G4SauterGavrilaAngularDistribution()
49 : G4VEmAngularDistribution("SauterGavrila") 49 : G4VEmAngularDistribution("SauterGavrila")
50 {} 50 {}
51 51
52 G4SauterGavrilaAngularDistribution::~G4SauterG << 52 G4SauterGavrilaAngularDistribution::~G4SauterGavrilaAngularDistribution()
53 = default; << 53 {}
54 54
55 G4ThreeVector& G4SauterGavrilaAngularDistribu 55 G4ThreeVector& G4SauterGavrilaAngularDistribution::SampleDirection(
56 const G4DynamicParticle* dp, G4double, 56 const G4DynamicParticle* dp, G4double, G4int, const G4Material*)
57 { 57 {
58 static const G4double emin = 1*CLHEP::eV; 58 static const G4double emin = 1*CLHEP::eV;
59 static const G4double emax = 100*CLHEP::MeV; 59 static const G4double emax = 100*CLHEP::MeV;
60 60
61 G4double energy = std::max(dp->GetKineticEne 61 G4double energy = std::max(dp->GetKineticEnergy(), emin);
62 if (energy > emax) { 62 if (energy > emax) {
63 fLocalDirection = dp->GetMomentumDirection 63 fLocalDirection = dp->GetMomentumDirection();
64 } else { 64 } else {
65 // Initial algorithm according Penelope 20 65 // Initial algorithm according Penelope 2008 manual and
66 // F.Sauter Ann. Physik 9, 217(1931); 11, 66 // F.Sauter Ann. Physik 9, 217(1931); 11, 454(1931).
67 // Modified according Penelope 2014 manual 67 // Modified according Penelope 2014 manual
68 G4double costheta = 0.0; 68 G4double costheta = 0.0;
69 69
70 // 1) initialize energy-dependent variable 70 // 1) initialize energy-dependent variables
71 // Variable naming according to Eq. (2.24) 71 // Variable naming according to Eq. (2.24) of Penelope Manual
72 // (pag. 44) 72 // (pag. 44)
73 G4double tau = energy/electron_mass_c2; 73 G4double tau = energy/electron_mass_c2;
74 G4double gamma = 1.0 + tau; 74 G4double gamma = 1.0 + tau;
75 G4double beta = std::sqrt(tau*(tau + 2.0)) 75 G4double beta = std::sqrt(tau*(tau + 2.0))/gamma;
76 76
77 // ac corresponds to "A" of Eq. (2.31) 77 // ac corresponds to "A" of Eq. (2.31)
78 // 78 //
79 G4double ac = (1.0 - beta)/beta; 79 G4double ac = (1.0 - beta)/beta;
80 G4double a1 = 0.5*beta*gamma*tau*(gamma-2. 80 G4double a1 = 0.5*beta*gamma*tau*(gamma-2.0);
81 G4double a2 = ac + 2.0; 81 G4double a2 = ac + 2.0;
82 // gtmax = maximum of the rejection functi 82 // gtmax = maximum of the rejection function according to Eq. (2.28),
83 // obtained for tsam=0 83 // obtained for tsam=0
84 G4double gtmax = 2.0*(a1 + 1.0/ac); 84 G4double gtmax = 2.0*(a1 + 1.0/ac);
85 85
86 G4double tsam = 0.0; 86 G4double tsam = 0.0;
87 G4double gtr = 0.0; 87 G4double gtr = 0.0;
88 88
89 //2) sampling. Eq. (2.31) of Penelope Manu 89 //2) sampling. Eq. (2.31) of Penelope Manual
90 // tsam = 1-std::cos(theta) 90 // tsam = 1-std::cos(theta)
91 // gtr = rejection function according to E 91 // gtr = rejection function according to Eq. (2.28)
92 do{ 92 do{
93 G4double rand = G4UniformRand(); 93 G4double rand = G4UniformRand();
94 tsam = 2.0*ac * (2.0*rand + a2*std::sqrt 94 tsam = 2.0*ac * (2.0*rand + a2*std::sqrt(rand)) / (a2*a2 - 4.0*rand);
95 gtr = (2.0 - tsam) * (a1 + 1.0/(ac+tsam) 95 gtr = (2.0 - tsam) * (a1 + 1.0/(ac+tsam));
96 // Loop checking, 03-Aug-2015, Vladimir 96 // Loop checking, 03-Aug-2015, Vladimir Ivanchenko
97 } while(G4UniformRand()*gtmax > gtr); 97 } while(G4UniformRand()*gtmax > gtr);
98 98
99 costheta = 1.0 - tsam; 99 costheta = 1.0 - tsam;
100 100
101 G4double sint = std::sqrt(tsam*(2.0 - tsam 101 G4double sint = std::sqrt(tsam*(2.0 - tsam));
102 G4double phi = CLHEP::twopi*G4UniformRand 102 G4double phi = CLHEP::twopi*G4UniformRand();
103 103
104 fLocalDirection.set(sint*std::cos(phi), si 104 fLocalDirection.set(sint*std::cos(phi), sint*std::sin(phi), costheta);
105 fLocalDirection.rotateUz(dp->GetMomentumDi 105 fLocalDirection.rotateUz(dp->GetMomentumDirection());
106 } 106 }
107 return fLocalDirection; 107 return fLocalDirection;
108 } 108 }
109 109
110 void G4SauterGavrilaAngularDistribution::Print 110 void G4SauterGavrilaAngularDistribution::PrintGeneratorInformation() const
111 { 111 {
112 G4cout << "\n" << G4endl; 112 G4cout << "\n" << G4endl;
113 G4cout << "Non-polarized photoelectric effec 113 G4cout << "Non-polarized photoelectric effect angular generator." << G4endl;
114 G4cout << "The Sauter-Gavrila distribution f 114 G4cout << "The Sauter-Gavrila distribution for the K-shell is used."<<G4endl;
115 G4cout << "Originally developed by M.Maire f 115 G4cout << "Originally developed by M.Maire for Geant3"
116 << G4endl; 116 << G4endl;
117 } 117 }
118 118
119 119