ParticleKillAction.cpp

// This file is part of the ACTS project.
//
// Copyright (C) 2016 CERN for the benefit of the ACTS project
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

#include "ActsExamples/Geant4/ParticleKillAction.hpp"

#include "Acts/Definitions/Algebra.hpp"
#include "Acts/Definitions/Units.hpp"
#include "ActsExamples/Geant4/AlgebraConverters.hpp"
#include "ActsFatras/EventData/Barcode.hpp"
#include "ActsFatras/EventData/ParticleOutcome.hpp"

#include <ostream>
#include <utility>

#include <G4RunManager.hh>
#include <G4Step.hh>
#include <G4StepPoint.hh>
#include <G4Track.hh>
#include <G4UnitsTable.hh>
#include <G4VPhysicalVolume.hh>

namespace ActsExamples::Geant4 {

ParticleKillAction::ParticleKillAction(
    const Config& cfg, std::unique_ptr<const Acts::Logger> logger)
    : G4UserSteppingAction(), m_cfg(cfg), m_logger(std::move(logger)) {}

void ParticleKillAction::UserSteppingAction(const G4Step* step) {
  constexpr double convertTime = Acts::UnitConstants::ns / CLHEP::ns;

  G4Track* track = step->GetTrack();

  const auto time = convertTime * track->GetGlobalTime();
  const bool isSecondary =
      track->GetDynamicParticle()->GetPrimaryParticle() == nullptr;

  const bool outOfVolume =
      m_cfg.volume &&
      !m_cfg.volume->inside(eventStore().geoContext,
                            convertPosition(track->GetPosition()));
  const bool outOfTime = time > m_cfg.maxTime;
  const bool invalidSecondary = m_cfg.secondaries && isSecondary;

  if (outOfVolume || outOfTime || invalidSecondary) {
    ACTS_DEBUG("Kill track with internal track ID "
               << track->GetTrackID() << " at "
               << convertPosition(track->GetPosition()) << " and global time "
               << time / Acts::UnitConstants::ns << "ns and isSecondary "
               << isSecondary);
    track->SetTrackStatus(G4TrackStatus::fStopAndKill);
  }

  // store the outcome of the particle
  auto trackIt = eventStore().trackIdMapping.find(track->GetTrackID());
  // check if we have a particle assigned to track
  if (trackIt != eventStore().trackIdMapping.end()) {
    // set the outcome of the particle
    const SimBarcode particleId = trackIt->second;
    if (outOfVolume) {
      eventStore().particleOutcome[particleId] =
          ActsFatras::ParticleOutcome::KilledVolumeExit;
    } else if (outOfTime) {
      eventStore().particleOutcome[particleId] =
          ActsFatras::ParticleOutcome::KilledTime;
    } else if (invalidSecondary) {
      eventStore().particleOutcome[particleId] =
          ActsFatras::ParticleOutcome::KilledSecondaryParticle;
    } else if (track->GetTrackStatus() == fStopAndKill) {
      eventStore().particleOutcome[particleId] =
          ActsFatras::ParticleOutcome::KilledInteraction;
    }
  }
}

}  // namespace ActsExamples::Geant4