FastOpticalPhysics.cxx

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// Adapted for LArSoft by Ben Jones, MIT, Nov 2012
//
// This class is based upon the default Geant4 optical physics constructor.
// However, for fast optical physics in LArSoft:
//
// - The default geant4 scintillation process is swapped for the LArG4 fast
//     scintillation process
//
// - Cerenkov light (still slow) can be enabled or disabled as required
//
// - The default geant4 reflection process is swapped for a simpler
//     custom boundary process in LArG4
//
// Parameters relating to the physics in this constructor can be set
// in the Utilities/LArParameters service.
//
//
// ********************************************************************
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// * the Geant4 Collaboration.  It is provided  under  the terms  and *
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// * work  make  any representation or  warranty, express or implied, *
// * regarding  this  software system or assume any liability for its *
// * use.  Please see the license in the file  LICENSE  and URL above *
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// * technical work of the GEANT4 collaboration.                      *
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//

#include "larsim/LegacyLArG4/FastOpticalPhysics.h"
#include "larsim/LegacyLArG4/OpBoundaryProcessSimple.hh"
#include "larsim/LegacyLArG4/OpFastScintillation.hh"

#include "larcore/CoreUtils/ServiceUtil.h"
#include "lardata/DetectorInfoServices/LArPropertiesService.h"

#include "messagefacility/MessageLogger/MessageLogger.h"

#include "Geant4/G4LossTableManager.hh"
#include "Geant4/G4ParticleDefinition.hh"
#include "Geant4/G4ParticleTable.hh"
#include "Geant4/G4ProcessManager.hh"

#include "Geant4/G4Alpha.hh"
#include "Geant4/G4AntiProton.hh"
#include "Geant4/G4Deuteron.hh"
#include "Geant4/G4Electron.hh"
#include "Geant4/G4Gamma.hh"
#include "Geant4/G4GenericIon.hh"
#include "Geant4/G4He3.hh"
#include "Geant4/G4KaonMinus.hh"
#include "Geant4/G4KaonPlus.hh"
#include "Geant4/G4MuonMinus.hh"
#include "Geant4/G4MuonPlus.hh"
#include "Geant4/G4OpticalPhoton.hh"
#include "Geant4/G4PionMinus.hh"
#include "Geant4/G4PionPlus.hh"
#include "Geant4/G4Positron.hh"
#include "Geant4/G4Proton.hh"
#include "Geant4/G4Triton.hh"

#include "Geant4/G4Cerenkov.hh"
#include "Geant4/G4OpAbsorption.hh"
#include "Geant4/G4OpRayleigh.hh"
#include "Geant4/G4OpWLS.hh"

namespace larg4 {

  //-----------------------------------------------------------
  FastOpticalPhysics::FastOpticalPhysics(G4int /*verbose*/, const G4String& name)
    : G4VPhysicsConstructor(name)
  {
    G4LossTableManager::Instance();
    mf::LogInfo("FastOpticalPhysics") << "OBJECT BEING CONSTRUCTED IN OPTICAL PHYSICS";
  }

  //-----------------------------------------------------------
  void
  FastOpticalPhysics::ConstructParticle()
  {
    MF_LOG_DEBUG("FastOpticalPhysics") << "PARTICLES BEING CONSTRUCTED IN FAST OPTICAL PHYSICS";
    // optical photon
    G4OpticalPhoton::OpticalPhotonDefinition();

    // gamma
    G4Gamma::Gamma();

    // leptons
    G4Electron::Electron();
    G4Positron::Positron();
    G4MuonPlus::MuonPlus();
    G4MuonMinus::MuonMinus();

    // mesons
    G4PionPlus::PionPlusDefinition();
    G4PionMinus::PionMinusDefinition();
    G4KaonPlus::KaonPlusDefinition();
    G4KaonMinus::KaonMinusDefinition();

    // barions
    G4Proton::Proton();
    G4AntiProton::AntiProton();

    // ions
    G4Deuteron::Deuteron();
    G4Triton::Triton();
    G4He3::He3();
    G4Alpha::Alpha();
    G4GenericIon::GenericIonDefinition();
  }

  //-----------------------------------------------------------
  void
  FastOpticalPhysics::ConstructProcess()
  {
    // Add standard EM Processes
    MF_LOG_DEBUG("FastOpticalPhysics") << "PROCESSES BEING CONSTRUCTED IN OPTICAL PHYSICS";

    fTheCerenkovProcess = new G4Cerenkov("Cerenkov");
    fTheAbsorptionProcess = new G4OpAbsorption();
    fTheRayleighScatteringProcess = new G4OpRayleigh();
    fTheBoundaryProcess = new OpBoundaryProcessSimple();
    fTheWLSProcess = new G4OpWLS();
    fTheScintillationProcess = std::make_unique<OpFastScintillation>("FastScintillation");

    fTheCerenkovProcess->SetMaxNumPhotonsPerStep(700);
    fTheCerenkovProcess->SetMaxBetaChangePerStep(10.0);
    fTheCerenkovProcess->SetTrackSecondariesFirst(false);

    const detinfo::LArProperties* larp = lar::providerFrom<detinfo::LArPropertiesService>();
    bool CerenkovEnabled = larp->CerenkovLightEnabled();

    mf::LogInfo("FastOpticalPhysics") << "Cerenkov enabled : " << CerenkovEnabled;
    static G4ParticleTable* fParticleTable = G4ParticleTable::GetParticleTable();
    G4ParticleTable::G4PTblDicIterator* aParticleIterator;
    aParticleIterator = fParticleTable->GetIterator();
    aParticleIterator->reset();
    while ((*aParticleIterator)()) {
      G4ParticleDefinition* particle = aParticleIterator->value();
      G4ProcessManager* pmanager = particle->GetProcessManager();
      G4String particleName = particle->GetParticleName();

      if (fTheCerenkovProcess->IsApplicable(*particle) && CerenkovEnabled) {
        pmanager->AddProcess(fTheCerenkovProcess);
        pmanager->SetProcessOrdering(fTheCerenkovProcess, idxPostStep);
      }
      if (fTheScintillationProcess->IsApplicable(*particle)) {
        auto ptr = fTheScintillationProcess.get();
        pmanager->AddProcess(ptr);
        pmanager->SetProcessOrderingToLast(ptr, idxAtRest);
        pmanager->SetProcessOrderingToLast(ptr, idxPostStep);
      }

      if (particleName == "opticalphoton") {
        mf::LogInfo("FastOptical") << " AddDiscreteProcess to OpticalPhoton ";
        pmanager->AddDiscreteProcess(fTheAbsorptionProcess);
        pmanager->AddDiscreteProcess(fTheRayleighScatteringProcess);
        pmanager->AddDiscreteProcess(fTheBoundaryProcess);
        pmanager->AddDiscreteProcess(fTheWLSProcess);
      }
    }
  }
}