FixG4CreatorProcess.cxx

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/*
  Copyright (C) 2002-2021 CERN for the benefit of the ATLAS collaboration
*/
 
#include "FixG4CreatorProcess.h"
 
#include "G4Step.hh"
#include "G4Event.hh"
#include "G4Gamma.hh"
#include "G4ParticleDefinition.hh"
#include "G4VProcess.hh"
#include "G4EmParameters.hh"
 
namespace G4UA
{
 
  //---------------------------------------------------------------------------
  FixG4CreatorProcess::FixG4CreatorProcess(){}
 
 
  //---------------------------------------------------------------------------
  void FixG4CreatorProcess::UserSteppingAction(const G4Step* aStep)
  {
    //
    //  M. Novak, M. Bandieramonte: 10 November 2021
    //  
    //  Make sure that the creator process of the secondary tracks of the current step
    //  is the same as the one that limited the step. These can be different in case of
    //  using `wrapper` processes e.g. G4GammaGeneralProcess or G4HepEm, etc.
    if (G4EmParameters::Instance()->GeneralProcessActive()) {
        const G4ParticleDefinition* thePrimaryParticle = aStep->GetTrack()->GetParticleDefinition();
        const std::size_t           numThisSecondaries = aStep->GetNumberOfSecondariesInCurrentStep();
        if (thePrimaryParticle==G4Gamma::GammaDefinition() && numThisSecondaries>0) {
                // Get the pointer to the process that limited the step: i.e. the one that
                // created the secondaries of the current step
            const G4VProcess* theLimiterProcess = aStep->GetPostStepPoint()->GetProcessDefinedStep();
            // note: this is a vector of secondaries containing all secondaries created
            // along the tracking of the current `primary` track (i.e. not only
            // secondaries created in this step)
            const G4TrackVector* theSecTrackVector = aStep->GetSecondary();
            const std::size_t    numAllSecondaries = theSecTrackVector->size();
            for (std::size_t it = numAllSecondaries-numThisSecondaries; it<numAllSecondaries; ++it) {
 
                G4Track* secTrack = (*theSecTrackVector)[it];
                if (secTrack->GetCreatorProcess()!=theLimiterProcess) {
 
                    secTrack->SetCreatorProcess(theLimiterProcess);
                }
                }
            }
 
    }   
 }
} // namespace G4UA