particleGun/src/PrimaryGeneratorAction1.cc

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0026 /// \file eventgenerator/particleGun/src/PrimaryGeneratorAction1.cc
0027 /// \brief Implementation of the PrimaryGeneratorAction1 class
0028 //
0029 //
0030 //
0031 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0032 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0033
0034 #include "PrimaryGeneratorAction1.hh"
0035
0036 #include "PrimaryGeneratorAction.hh"
0037
0038 #include "G4Event.hh"
0039 #include "G4ParticleDefinition.hh"
0040 #include "G4ParticleGun.hh"
0041 #include "G4ParticleTable.hh"
0042 #include "G4PhysicalConstants.hh"
0043 #include "G4SystemOfUnits.hh"
0044 #include "Randomize.hh"
0045
0046 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0047
0048 PrimaryGeneratorAction1::PrimaryGeneratorAction1(G4ParticleGun* gun) : fParticleGun(gun) {}
0049
0050 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0051
0052 void PrimaryGeneratorAction1::GeneratePrimaries(G4Event* anEvent)
0053 {
0054   const G4double r = 2 * mm;
0055   const G4double zmax = 8 * mm;
0056
0057   // vertex 1 uniform on cylinder
0058   //
0059   G4double alpha = twopi * G4UniformRand();  // alpha uniform in (0, 2*pi)
0060   G4double ux = std::cos(alpha);
0061   G4double uy = std::sin(alpha);
0062   G4double z = zmax * (2 * G4UniformRand() - 1);  // z uniform in (-zmax, +zmax)
0063
0064   fParticleGun->SetParticlePosition(G4ThreeVector(r * ux, r * uy, z));
0065   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(ux, uy, 0));
0066   fParticleGun->SetParticleEnergy(1 * MeV);
0067   fParticleGun->GeneratePrimaryVertex(anEvent);
0068
0069   // vertex 2 at opposite
0070   //
0071   alpha += pi;
0072   ux = std::cos(alpha);
0073   uy = std::sin(alpha);
0074   fParticleGun->SetParticlePosition(G4ThreeVector(r * ux, r * uy, z));
0075
0076   // particle 2 at vertex 2
0077   //
0078   const G4double dalpha = 10 * deg;
0079   ux = std::cos(alpha + dalpha);
0080   uy = std::sin(alpha + dalpha);
0081
0082   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(ux, uy, 0));
0083   fParticleGun->SetParticleEnergy(1 * keV);
0084   fParticleGun->GeneratePrimaryVertex(anEvent);
0085
0086   // particle 3 at vertex 3 (same as vertex 2)
0087   //
0088   ux = std::cos(alpha - dalpha);
0089   uy = std::sin(alpha - dalpha);
0090
0091   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(ux, uy, 0));
0092   fParticleGun->SetParticleEnergy(1 * GeV);
0093   fParticleGun->GeneratePrimaryVertex(anEvent);
0094
0095   // randomize time zero of anEvent
0096   //
0097   G4double tmin = 0 * s, tmax = 10 * s;
0098   G4double t0 = tmin + (tmax - tmin) * G4UniformRand();
0099   G4PrimaryVertex* aVertex = anEvent->GetPrimaryVertex();
0100   while (aVertex) {
0101     aVertex->SetT0(t0);
0102     aVertex = aVertex->GetNext();
0103   }
0104 }
0105
0106 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......