G4AdjointPrimaryGeneratorAction.cc

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//
// G4AdjointPrimaryGeneratorAction implementation
//
// --------------------------------------------------------------------
//   Class Name:   G4AdjointPrimaryGeneratorAction
//   Author:       L. Desorgher, 2007-2009
//   Organisation: SpaceIT GmbH
//   Contract:     ESA contract 21435/08/NL/AT
//   Customer:     ESA/ESTEC
// --------------------------------------------------------------------
 
#include "G4AdjointPrimaryGeneratorAction.hh"
 
#include "G4AdjointPrimaryGenerator.hh"
#include "G4AdjointSimManager.hh"
#include "G4Event.hh"
#include "G4Gamma.hh"
#include "G4ParticleDefinition.hh"
#include "G4ParticleTable.hh"
#include "G4PhysicalConstants.hh"
 
// --------------------------------------------------------------------
//
G4AdjointPrimaryGeneratorAction::G4AdjointPrimaryGeneratorAction()
{
  
  PrimariesConsideredInAdjointSim[G4String("e-")] = false;
  PrimariesConsideredInAdjointSim[G4String("gamma")] = false;
  PrimariesConsideredInAdjointSim[G4String("proton")] = false;
  PrimariesConsideredInAdjointSim[G4String("ion")] = false;
 
  ListOfPrimaryFwdParticles.clear();
  ListOfPrimaryAdjParticles.clear();
}
 
// --------------------------------------------------------------------
//
G4AdjointPrimaryGeneratorAction::~G4AdjointPrimaryGeneratorAction()
{
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
{
  G4int evt_id = anEvent->GetEventID();
  std::size_t n = ListOfPrimaryAdjParticles.size();
  index_particle = std::size_t(evt_id) - n * (std::size_t(evt_id) / n);
 
  G4double E1 = Emin;
  G4double E2 = Emax;
  if (ListOfPrimaryAdjParticles[index_particle] == nullptr)
    UpdateListOfPrimaryParticles();  // ion has not been created yet
 
  if (ListOfPrimaryAdjParticles[index_particle]->GetParticleName() == "adj_proton") {
    E1 = EminIon;
    E2 = EmaxIon;
  }
  if (ListOfPrimaryAdjParticles[index_particle]->GetParticleType() == "adjoint_nucleus") {
    G4int A = ListOfPrimaryAdjParticles[index_particle]->GetAtomicMass();
    E1 = EminIon * A;
    E2 = EmaxIon * A;
  }
  // Generate first the forwrad primaries
    G4AdjointPrimaryGenerator::GetInstance()->GenerateFwdPrimaryVertex(anEvent, ListOfPrimaryFwdParticles[index_particle], E1, E2);
 
  G4PrimaryVertex* fwdPrimVertex = anEvent->GetPrimaryVertex();
 
  p = fwdPrimVertex->GetPrimary()->GetMomentum();
  pos = fwdPrimVertex->GetPosition();
  G4double pmag = p.mag();
  G4double m0 = ListOfPrimaryFwdParticles[index_particle]->GetPDGMass();
  G4double ekin = std::sqrt(m0 * m0 + pmag * pmag) - m0;
 
  G4double weight_correction = 1.;
  // For gamma generate the particle along the backward ray
  G4ThreeVector dir = -p / p.mag();
 
  weight_correction = 1.;
 
  if (ListOfPrimaryFwdParticles[index_particle] == G4Gamma::Gamma() && nb_fwd_gammas_per_event > 1)
  {
    G4double weight = (1. / nb_fwd_gammas_per_event);
    fwdPrimVertex->SetWeight(weight);
    for (G4int i = 0; i < nb_fwd_gammas_per_event - 1; ++i) {
      auto newFwdPrimVertex = new G4PrimaryVertex();
      newFwdPrimVertex->SetPosition(pos.x(), pos.y(), pos.z());
      newFwdPrimVertex->SetT0(0.);
      auto aPrimParticle =
        new G4PrimaryParticle(ListOfPrimaryFwdParticles[index_particle], p.x(), p.y(), p.z());
      newFwdPrimVertex->SetPrimary(aPrimParticle);
      newFwdPrimVertex->SetWeight(weight);
      anEvent->AddPrimaryVertex(newFwdPrimVertex);
    }
  }
 
  // Now generate the adjoint primaries
  auto adjPrimVertex = new G4PrimaryVertex();
  adjPrimVertex->SetPosition(pos.x(), pos.y(), pos.z());
  adjPrimVertex->SetT0(0.);
  auto aPrimParticle =
    new G4PrimaryParticle(ListOfPrimaryAdjParticles[index_particle], -p.x(), -p.y(), -p.z());
 
  adjPrimVertex->SetPrimary(aPrimParticle);
  anEvent->AddPrimaryVertex(adjPrimVertex);
 
  // The factor pi is to normalise the weight to the directional flux
  G4double adjoint_source_area = G4AdjointSimManager::GetInstance()->GetAdjointSourceArea();
  G4double adjoint_weight =
    weight_correction * ComputeEnergyDistWeight(ekin, E1, E2) * adjoint_source_area * pi;
  if (ListOfPrimaryAdjParticles[index_particle]->GetParticleName() == "adj_gamma") {
    // The weight will be corrected at the end of the track if splitted tracks
    // are used
    adjoint_weight = adjoint_weight / nb_adj_primary_gammas_per_event;
    for (G4int i = 0; i < nb_adj_primary_gammas_per_event - 1; ++i) {
      auto newAdjPrimVertex = new G4PrimaryVertex();
      newAdjPrimVertex->SetPosition(pos.x(), pos.y(), pos.z());
      newAdjPrimVertex->SetT0(0.);
      aPrimParticle =
        new G4PrimaryParticle(ListOfPrimaryAdjParticles[index_particle], -p.x(), -p.y(), -p.z());
      newAdjPrimVertex->SetPrimary(aPrimParticle);
      newAdjPrimVertex->SetWeight(adjoint_weight);
      anEvent->AddPrimaryVertex(newAdjPrimVertex);
    }
  }
  else if (ListOfPrimaryAdjParticles[index_particle]->GetParticleName() == "adj_electron") {
    // The weight will be corrected at the end of the track if splitted tracks
    // are used
    adjoint_weight = adjoint_weight / nb_adj_primary_electrons_per_event;
    for (G4int i = 0; i < nb_adj_primary_electrons_per_event - 1; ++i) {
      auto newAdjPrimVertex = new G4PrimaryVertex();
      newAdjPrimVertex->SetPosition(pos.x(), pos.y(), pos.z());
      newAdjPrimVertex->SetT0(0.);
      aPrimParticle =
        new G4PrimaryParticle(ListOfPrimaryAdjParticles[index_particle], -p.x(), -p.y(), -p.z());
      newAdjPrimVertex->SetPrimary(aPrimParticle);
      newAdjPrimVertex->SetWeight(adjoint_weight);
      anEvent->AddPrimaryVertex(newAdjPrimVertex);
    }
  }
  adjPrimVertex->SetWeight(adjoint_weight);
 
  // Call some methods of G4AdjointSimManager
  G4AdjointSimManager::GetInstance()->SetAdjointTrackingMode(true);
  G4AdjointSimManager::GetInstance()->ClearEndOfAdjointTrackInfoVectors();
  G4AdjointSimManager::GetInstance()->ResetDidOneAdjPartReachExtSourceDuringEvent();
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetEmin(G4double val)
{
  Emin = val;
  EminIon = val;
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetEmax(G4double val)
{
  Emax = val;
  EmaxIon = val;
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetEminIon(G4double val)
{
  EminIon = val;
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetEmaxIon(G4double val)
{
  EmaxIon = val;
}
 
// --------------------------------------------------------------------
//
G4double G4AdjointPrimaryGeneratorAction::ComputeEnergyDistWeight(G4double E, G4double E1,
                                                                  G4double E2)
{
  // We generate N numbers of primaries with  a 1/E energy law distribution.
  // We have therefore  an energy distribution function
  //   f(E)=C/E  (1)
  // with   C a constant that is such that
  //   N=Integral(f(E),E1,E2)=C.std::log(E2/E1)  (2)
  // Therefore from (2) we get
  //   C=N/ std::log(E2/E1) (3)
  // and
  //   f(E)=N/ std::log(E2/E1)/E (4)
  // For the adjoint simulation we need a energy distribution  f'(E)=1..
  // To get that we need therefore to apply a weight to the primary
  //   W=1/f(E)=E*std::log(E2/E1)/N
  //
  return std::log(E2 / E1) * E / G4AdjointSimManager::GetInstance()->GetNbEvtOfLastRun();
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetSphericalAdjointPrimarySource(G4double radius,
                                                                       G4ThreeVector center_pos)
{
  radius_spherical_source = radius;
  center_spherical_source = center_pos;
  type_of_adjoint_source = "Spherical";
   G4AdjointPrimaryGenerator::GetInstance()->SetSphericalAdjointPrimarySource(radius, center_pos);
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetAdjointPrimarySourceOnAnExtSurfaceOfAVolume(
  const G4String& volume_name)
{
  type_of_adjoint_source = "ExternalSurfaceOfAVolume";
   G4AdjointPrimaryGenerator::GetInstance()->SetAdjointPrimarySourceOnAnExtSurfaceOfAVolume(volume_name);
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::ConsiderParticleAsPrimary(const G4String& particle_name)
{
  if (PrimariesConsideredInAdjointSim.find(particle_name) != PrimariesConsideredInAdjointSim.end())
  {
    PrimariesConsideredInAdjointSim[particle_name] = true;
  }
  UpdateListOfPrimaryParticles();
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::NeglectParticleAsPrimary(const G4String& particle_name)
{
  if (PrimariesConsideredInAdjointSim.find(particle_name) != PrimariesConsideredInAdjointSim.end())
  {
    PrimariesConsideredInAdjointSim[particle_name] = false;
  }
  UpdateListOfPrimaryParticles();
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::UpdateListOfPrimaryParticles()
{
  G4ParticleTable* theParticleTable = G4ParticleTable::GetParticleTable();
  ListOfPrimaryFwdParticles.clear();
  ListOfPrimaryAdjParticles.clear();
  for (const auto& iter : PrimariesConsideredInAdjointSim) {
    if (iter.second) {
      G4String fwd_particle_name = iter.first;
      if (fwd_particle_name != "ion") {
        G4String adj_particle_name = G4String("adj_") + fwd_particle_name;
        ListOfPrimaryFwdParticles.push_back(theParticleTable->FindParticle(fwd_particle_name));
        ListOfPrimaryAdjParticles.push_back(theParticleTable->FindParticle(adj_particle_name));
      }
      else {
        if (fwd_ion != nullptr) {
          ion_name = fwd_ion->GetParticleName();
          G4String adj_ion_name = G4String("adj_") + ion_name;
          ListOfPrimaryFwdParticles.push_back(fwd_ion);
          ListOfPrimaryAdjParticles.push_back(adj_ion);
        }
        else {
          ListOfPrimaryFwdParticles.push_back(nullptr);
          ListOfPrimaryAdjParticles.push_back(nullptr);
        }
      }
    }
  }
}
 
// --------------------------------------------------------------------
//
void G4AdjointPrimaryGeneratorAction::SetPrimaryIon(G4ParticleDefinition* adjointIon,
                                                    G4ParticleDefinition* fwdIon)
{
  fwd_ion = fwdIon;
  adj_ion = adjointIon;
  UpdateListOfPrimaryParticles();
}