B1/src/PrimaryGeneratorAction.cc

0001 //
0002 // ********************************************************************
0003 // * License and Disclaimer                                           *
0004 // *                                                                  *
0005 // * The  Geant4 software  is  copyright of the Copyright Holders  of *
0006 // * the Geant4 Collaboration.  It is provided  under  the terms  and *
0007 // * conditions of the Geant4 Software License,  included in the file *
0008 // * LICENSE and available at  http://cern.ch/geant4/license .  These *
0009 // * include a list of copyright holders.                             *
0010 // *                                                                  *
0011 // * Neither the authors of this software system, nor their employing *
0012 // * institutes,nor the agencies providing financial support for this *
0013 // * work  make  any representation or  warranty, express or implied, *
0014 // * regarding  this  software system or assume any liability for its *
0015 // * use.  Please see the license in the file  LICENSE  and URL above *
0016 // * for the full disclaimer and the limitation of liability.         *
0017 // *                                                                  *
0018 // * This  code  implementation is the result of  the  scientific and *
0019 // * technical work of the GEANT4 collaboration.                      *
0020 // * By using,  copying,  modifying or  distributing the software (or *
0021 // * any work based  on the software)  you  agree  to acknowledge its *
0022 // * use  in  resulting  scientific  publications,  and indicate your *
0023 // * acceptance of all terms of the Geant4 Software license.          *
0024 // ********************************************************************
0025 //
0026 //
0027 /// \file B1/src/PrimaryGeneratorAction.cc
0028 /// \brief Implementation of the B1::PrimaryGeneratorAction class
0029
0030 #include "PrimaryGeneratorAction.hh"
0031
0032 #include "G4Box.hh"
0033 #include "G4LogicalVolume.hh"
0034 #include "G4LogicalVolumeStore.hh"
0035 #include "G4ParticleGun.hh"
0036 #include "G4ParticleTable.hh"
0037 #include "G4SystemOfUnits.hh"
0038 #include "Randomize.hh"
0039
0040 namespace B1
0041 {
0042
0043 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0044
0045 PrimaryGeneratorAction::PrimaryGeneratorAction()
0046 {
0047   G4int n_particle = 1;
0048   fParticleGun = new G4ParticleGun(n_particle);
0049
0050   // default particle kinematic
0051   G4ParticleTable* particleTable = G4ParticleTable::GetParticleTable();
0052   G4String particleName;
0053   G4ParticleDefinition* particle = particleTable->FindParticle(particleName = "gamma");
0054   fParticleGun->SetParticleDefinition(particle);
0055   fParticleGun->SetParticleMomentumDirection(G4ThreeVector(0., 0., 1.));
0056   fParticleGun->SetParticleEnergy(6. * MeV);
0057 }
0058
0059 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0060
0061 PrimaryGeneratorAction::~PrimaryGeneratorAction()
0062 {
0063   delete fParticleGun;
0064 }
0065
0066 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0067
0068 void PrimaryGeneratorAction::GeneratePrimaries(G4Event* event)
0069 {
0070   // this function is called at the begining of ecah event
0071   //
0072
0073   // In order to avoid dependence of PrimaryGeneratorAction
0074   // on DetectorConstruction class we get Envelope volume
0075   // from G4LogicalVolumeStore.
0076
0077   G4double envSizeXY = 0;
0078   G4double envSizeZ = 0;
0079
0080   if (!fEnvelopeBox) {
0081     G4LogicalVolume* envLV = G4LogicalVolumeStore::GetInstance()->GetVolume("Envelope");
0082     if (envLV) fEnvelopeBox = dynamic_cast<G4Box*>(envLV->GetSolid());
0083   }
0084
0085   if (fEnvelopeBox) {
0086     envSizeXY = fEnvelopeBox->GetXHalfLength() * 2.;
0087     envSizeZ = fEnvelopeBox->GetZHalfLength() * 2.;
0088   }
0089   else {
0090     G4ExceptionDescription msg;
0091     msg << "Envelope volume of box shape not found.\n";
0092     msg << "Perhaps you have changed geometry.\n";
0093     msg << "The gun will be place at the center.";
0094     G4Exception("PrimaryGeneratorAction::GeneratePrimaries()", "MyCode0002", JustWarning, msg);
0095   }
0096
0097   G4double size = 0.8;
0098   G4double x0 = size * envSizeXY * (G4UniformRand() - 0.5);
0099   G4double y0 = size * envSizeXY * (G4UniformRand() - 0.5);
0100   G4double z0 = -0.5 * envSizeZ;
0101
0102   fParticleGun->SetParticlePosition(G4ThreeVector(x0, y0, z0));
0103
0104   fParticleGun->GeneratePrimaryVertex(event);
0105 }
0106
0107 //....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
0108
0109 }  // namespace B1