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26 //
27 /// \file B5/src/PrimaryGeneratorAction.cc
28 /// \brief Implementation of the B5::PrimaryGeneratorAction class
29
30 #include "PrimaryGeneratorAction.hh"
31
32 #include "G4GenericMessenger.hh"
33 #include "G4ParticleDefinition.hh"
34 #include "G4ParticleGun.hh"
35 #include "G4ParticleTable.hh"
36 #include "G4SystemOfUnits.hh"
37 #include "G4ThreeVector.hh"
38 #include "Randomize.hh"
39
40 namespace B5
41 {
42
43 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
44
45 PrimaryGeneratorAction::PrimaryGeneratorAction()
46 {
47 G4int nofParticles = 1;
48 fParticleGun = new G4ParticleGun(nofParticles);
49
50 auto particleTable = G4ParticleTable::GetParticleTable();
51 fPositron = particleTable->FindParticle("e+");
52 fMuon = particleTable->FindParticle("mu+");
53 fPion = particleTable->FindParticle("pi+");
54 fKaon = particleTable->FindParticle("kaon+");
55 fProton = particleTable->FindParticle("proton");
56
57 // default particle kinematics
58 fParticleGun->SetParticlePosition(G4ThreeVector(0., 0., -8. * m));
59 fParticleGun->SetParticleDefinition(fPositron);
60
61 // define commands for this class
62 DefineCommands();
63 }
64
65 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
66
67 PrimaryGeneratorAction::~PrimaryGeneratorAction()
68 {
69 delete fParticleGun;
70 delete fMessenger;
71 }
72
73 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
74
75 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* event)
76 {
77 G4ParticleDefinition* particle;
78 if (fRandomizePrimary) {
79 auto i = (int)(5. * G4UniformRand());
80 switch (i) {
81 case 0:
82 particle = fPositron;
83 break;
84 case 1:
85 particle = fMuon;
86 break;
87 case 2:
88 particle = fPion;
89 break;
90 case 3:
91 particle = fKaon;
92 break;
93 default:
94 particle = fProton;
95 break;
96 }
97 fParticleGun->SetParticleDefinition(particle);
98 }
99 else {
100 particle = fParticleGun->GetParticleDefinition();
101 }
102
103 auto pp = fMomentum + (G4UniformRand() - 0.5) * fSigmaMomentum;
104 auto mass = particle->GetPDGMass();
105 auto ekin = std::sqrt(pp * pp + mass * mass) - mass;
106 fParticleGun->SetParticleEnergy(ekin);
107
108 auto angle = (G4UniformRand() - 0.5) * fSigmaAngle;
109 fParticleGun->SetParticleMomentumDirection(G4ThreeVector(std::sin(angle), 0., std::cos(angle)));
110
111 fParticleGun->GeneratePrimaryVertex(event);
112 }
113
114 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
115
116 void PrimaryGeneratorAction::DefineCommands()
117 {
118 // Define /B5/generator command directory using generic messenger class
119 fMessenger = new G4GenericMessenger(this, "/B5/generator/", "Primary generator control");
120
121 // momentum command
122 auto& momentumCmd = fMessenger->DeclarePropertyWithUnit("momentum", "GeV", fMomentum,
123 "Mean momentum of primaries.");
124 momentumCmd.SetParameterName("p", true);
125 momentumCmd.SetRange("p>=0.");
126 momentumCmd.SetDefaultValue("1.");
127 // ok
128 // momentumCmd.SetParameterName("p", true);
129 // momentumCmd.SetRange("p>=0.");
130
131 // sigmaMomentum command
132 auto& sigmaMomentumCmd = fMessenger->DeclarePropertyWithUnit(
133 "sigmaMomentum", "MeV", fSigmaMomentum, "Sigma momentum of primaries.");
134 sigmaMomentumCmd.SetParameterName("sp", true);
135 sigmaMomentumCmd.SetRange("sp>=0.");
136 sigmaMomentumCmd.SetDefaultValue("50.");
137
138 // sigmaAngle command
139 auto& sigmaAngleCmd = fMessenger->DeclarePropertyWithUnit("sigmaAngle", "deg", fSigmaAngle,
140 "Sigma angle divergence of primaries.");
141 sigmaAngleCmd.SetParameterName("t", true);
142 sigmaAngleCmd.SetRange("t>=0.");
143 sigmaAngleCmd.SetDefaultValue("2.");
144
145 // randomizePrimary command
146 auto& randomCmd = fMessenger->DeclareProperty("randomizePrimary", fRandomizePrimary);
147 G4String guidance = "Boolean flag for randomizing primary particle types.\n";
148 guidance += "In case this flag is false, you can select the primary particle\n";
149 guidance += " with /gun/particle command.";
150 randomCmd.SetGuidance(guidance);
151 randomCmd.SetParameterName("flg", true);
152 randomCmd.SetDefaultValue("true");
153 }
154
155 //..oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
156
157 } // namespace B5
158