sTGCSensitiveDetector.cxx

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/*
  Copyright (C) 2002-2025 CERN for the benefit of the ATLAS collaboration
*/
 
#include "sTGCSensitiveDetector.h"
#include "MCTruth/AtlasG4EventUserInfo.h"
#include "MCTruth/TrackHelper.h"
#include "G4Geantino.hh"
#include "G4ChargedGeantino.hh"
 
#include "G4Exception.hh"
#include "G4Track.hh"
 
#include "GeoPrimitives/CLHEPtoEigenConverter.h"
#include "GeoPrimitives/GeoPrimitivesToStringConverter.h"
 
#include <string>
 
 
// construction/destruction
sTGCSensitiveDetector::sTGCSensitiveDetector(const std::string& name, 
                                             const std::string& hitCollectionName,
                                             unsigned baseDepth): 
    G4VSensitiveDetector( name ),
    AthMessaging{name},
    m_hitCollectionName( hitCollectionName ),
    m_baseDepth{baseDepth} {}
 
// Implemenation of memebr functions
void sTGCSensitiveDetector::Initialize(G4HCofThisEvent*)
{
  m_sTGCSimHitCollection = nullptr;
  if (auto* eventInfo = AtlasG4EventUserInfo::GetEventUserInfo()) {
    m_sTGCSimHitCollection = eventInfo->GetHitCollectionMap()->Find<sTGCSimHitCollection>(m_hitCollectionName);
    m_g4UserEventInfo = eventInfo;
  }
}
 
G4bool sTGCSensitiveDetector::ProcessHits(G4Step* aStep,G4TouchableHistory* /*ROHist*/)
{
  if (!m_sTGCSimHitCollection) {
    G4Exception("sTGCSensitiveDetector::ProcessHits", "sTGCHitCollectionMissing", FatalException,
                "Hit collection not initialized; did SetupEvent run?");
    return false;
  }
  G4Track* currentTrack = aStep->GetTrack();
  int charge=currentTrack->GetDefinition()->GetPDGCharge();
 
  bool geantinoHit = (currentTrack->GetDefinition()==G4Geantino::GeantinoDefinition()) ||
                     (currentTrack->GetDefinition()==G4ChargedGeantino::ChargedGeantinoDefinition());
 
  if (!charge && (!geantinoHit)) return false;
  //  G4cout << "\t\t sTGCSD: Hit in a sensitive layer!!!!! " << G4endl;
  G4StepPoint* postStep=aStep->GetPostStepPoint();
  const G4Step* post_Step=aStep->GetTrack()->GetStep();
 
  Amg::Vector3D position = Amg::Hep3VectorToEigen(postStep->GetPosition());
  
  G4StepPoint* preStep = aStep->GetPreStepPoint();
  Amg::Vector3D preposition = Amg::Hep3VectorToEigen(preStep->GetPosition());
 
  int pdgCode=currentTrack->GetDefinition()->GetPDGEncoding();
 
  float globalTime=postStep->GetGlobalTime();
 
  Amg::Vector3D direction= Amg::Hep3VectorToEigen( postStep->GetMomentumDirection() );
  float depositEnergy=post_Step->GetTotalEnergyDeposit();
 
  if (depositEnergy<0.0001 && (!geantinoHit)) return false;
 
  const G4TouchableHistory* touchHist = static_cast<const G4TouchableHistory*>(aStep->GetPreStepPoint()->GetTouchable());
 
  // int iDepth=touchHist->GetHistoryDepth();
  //  G4cout << "\t\t\t\t Touchable history dump "<<G4endl;
  int nLayer=touchHist->GetVolume(m_baseDepth)->GetCopyNo();
  std::string chName=touchHist->GetVolume(1+m_baseDepth)->GetLogicalVolume()->GetName();
  //G4cout << "sTGCSensitiveDetector name: "<<chName<<G4endl;
  std::string subType=chName.substr(chName.find('-')+1);
  //G4cout << "\t\t sType: "<<subType);
  if (subType[0]!='T'&&subType[0]!='Q' ) ATH_MSG_WARNING(" something is wrong, this is no sTGC! "<<chName<<", "<<Amg::toString(preposition));
  int iRing = std::atoi(&subType[2]) -1;
  ATH_MSG_VERBOSE("Volume name: "<<chName<<", nLayer: "<<nLayer<<", subType: "<<subType<<", iRing: "<<iRing);
 
  // identifiers have eta naming 0-2, eta encoded in subtype is 1-3
  // double phiDiff=2*M_PI;
 
  G4ThreeVector posH=postStep->GetPosition(); //posH is equivalent to position - eigen not used to avoid additional dependence on EventPrimitives
  if (subType[1]=='L') posH.rotateZ(M_PI/8.);
  double phiHit=posH.phi();
  if(phiHit<=0) phiHit+=2.*M_PI;
  int iPhi=1+int(phiHit/(M_PI/4.));
  iPhi*=2;
  if (subType[1]=='L') iPhi-=1;
 
  int iSide=1;
  if (position.z()<0) iSide=-1;
 
  int mLayer=0;
  if (subType[1]=='S')
  {
    if (subType[3]=='C') mLayer=1;
    else if (subType[3]=='P') mLayer=2;
  }
  else if (subType[1]=='L')
  {
    if (subType[3]=='P') mLayer=1;
    else if (subType[3]=='C') mLayer=2;
  }
 
  if (mLayer != 1 && mLayer !=2) G4cout << " something is wrong - multilayer index is " << mLayer << G4endl;
 
  int sTgcId = m_muonHelper->BuildsTgcHitId(subType, iPhi, iRing, mLayer,nLayer, iSide);
  TrackHelper trHelp(aStep->GetTrack());
 
  m_sTGCSimHitCollection->Emplace(sTgcId,globalTime,position,pdgCode,direction,depositEnergy,
                                  trHelp.GenerateParticleLink(m_g4UserEventInfo ? m_g4UserEventInfo->GetEventStore() : nullptr),
                                  preStep->GetKineticEnergy(),preposition);
 
  return true;
}