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25 //
26 /// \file medical/electronScattering/src/PrimaryGeneratorAction.cc
27 /// \brief Implementation of the PrimaryGeneratorAction class
28 //
29 //
30 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
31 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
32
33 #include "PrimaryGeneratorAction.hh"
34
35 #include "DetectorConstruction.hh"
36 #include "PrimaryGeneratorMessenger.hh"
37
38 #include "G4Event.hh"
39 #include "G4ParticleDefinition.hh"
40 #include "G4ParticleTable.hh"
41 #include "G4SystemOfUnits.hh"
42 #include "Randomize.hh"
43
44 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
45
46 PrimaryGeneratorAction::PrimaryGeneratorAction(DetectorConstruction* DC)
47 : fParticleGun(0), fDetector(DC), fGunMessenger(0)
48 {
49 fParticleGun = new G4ParticleGun(1);
50
51 G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
52 G4ParticleDefinition* particle = particleTable->FindParticle("e-");
53 fParticleGun->SetParticleDefinition(particle);
54 fParticleGun->SetParticleEnergy(20. * MeV);
55 fZ0 = -0.5 * (fDetector->GetThicknessWorld());
56 fParticleGun->SetParticlePosition(G4ThreeVector(0 * cm, 0 * cm, fZ0));
57 fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
58
59 G4double radiusWorld = fDetector->GetRadiusWorld();
60 fR2World = radiusWorld * radiusWorld;
61 fRndmBeam = 420 * um;
62
63 // create a messenger for this class
64 fGunMessenger = new PrimaryGeneratorMessenger(this);
65 }
66
67 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
68
69 PrimaryGeneratorAction::~PrimaryGeneratorAction()
70 {
71 delete fParticleGun;
72 delete fGunMessenger;
73 }
74
75 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
76
77 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
78 {
79 // this function is called at the begining of event
80 //
81 // randomize beam, if requested.
82 if (fRndmBeam > 0.) {
83 G4double s_proj = fRndmBeam / std::sqrt(2.);
84 G4double x0, y0;
85 do {
86 x0 = G4RandGauss::shoot(0., s_proj);
87 y0 = G4RandGauss::shoot(0., s_proj);
88 } while ((x0 * x0 + y0 * y0) > fR2World);
89 fParticleGun->SetParticlePosition(G4ThreeVector(x0, y0, fZ0));
90 }
91
92 fParticleGun->GeneratePrimaryVertex(anEvent);
93 }
94
95 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
96