#include <TGCSensitiveDetectorCosmics.h>

Inheritance diagram for TGCSensitiveDetectorCosmics:

Collaboration diagram for TGCSensitiveDetectorCosmics:

Public Member Functions
	TGCSensitiveDetectorCosmics (const std::string &name, const std::string &hitCollectionName)
	construction/destruction More...

	~TGCSensitiveDetectorCosmics ()

void	Initialize (G4HCofThisEvent *HCE) override final
	member functions More...

G4bool	ProcessHits (G4Step aStep, G4TouchableHistory ROHist) override final

Private Member Functions
	FRIEND_TEST (TGCSensitiveDetectorCosmicstest, Initialize)

	FRIEND_TEST (TGCSensitiveDetectorCosmicstest, ProcessHits)

Private Attributes
Amg::Vector3D	m_mom

double	m_momMag

Amg::Vector3D	m_vertex

Amg::Vector3D	m_currVertex

Amg::Vector3D	m_globH

double	m_globalTime

SG::WriteHandle< TGCSimHitCollection >	m_myTGCHitColl
	member data More...

const TgcHitIdHelper *	m_muonHelper

Detailed Description

Author: haseg.nosp@m.awa@.nosp@m.azusa.nosp@m..shi.nosp@m.nshu-.nosp@m.u.ac.nosp@m..jp

methods and properties

The method TGCSensitiveDetectorCosmics::ProcessHits is executed by the G4 kernel each time a charged particle (or a geantino) crosses one of the TGC Gas volumes.

Navigating with the touchableHistory method GetHistoryDepth() through the hierarchy of the volumes crossed by the particles, the TGCSensitiveDetectorCosmicsCosmicsdeterminates the correct set of geometry parameters to be folded in the Simulation Identifier associated to each hit. The TGC SimIDs are 32-bit unsigned integers, built using the MuonSimEvent/TgcHitIdHelper class which inherits from the MuonHitIdHelper base class.

The modified version (Daniela Rebuzzi, 16/12/2005) calculates the tof for the cosmics, using as t0 the time to the closest approach of the track to (0,0,0). This implementation works also for slow particles, since the discrimination physics event/cosmics is done relying on the G4Track vertex (not on the tof).

We describe in the following, how each field of the identifier is retrieved.

1) stationName and stationPhi: when a volume is found in the hierarchy, whose name contains the substring "station", the stationName is extracted from the volume's name; stationPhi is calculated starting from the volume copy number assigned by MuonGeoModel. Separate cases when the station are "F" or "E" type.

2) stationEta: when a volume is found in the hierarchy, whose name contains the substring "tgccomponent", stationEta is calculated starting from the volume copy number assigned by MuonGeoModel. Possibility to calculate the stationPhi at this level, from the copy number assigned by MuonGeoModel (if the copyNo > 1000).

3) gasGap: when a volume is found in the hierarchy, whose name contains the substring "Gas Volume Layer" or "TGCGas", the gasGap is calculated from the volume copy number, according to the positive or negative Z value, in the Atlas global reference system.

@section Some notes:

1) since the volume copy numbers strongly depend on the database layout, the volume name (whether it contains the string "Q02", for instance) is used to retrieve geometry information. In the year 2018 and even some years before there are not any more other database layouts / volumes than MUONQ02 and therefore some logic was removed.

2) for each hit, the time of flight (the G4 globalTime), is recorded and associated to the hit.

3) the TGCHit object contains: the SimID, the globalTime, the hit position in the local reference system, the track director cosine in the local reference system and the track identifier.

Definition at line 75 of file TGCSensitiveDetectorCosmics.h.

Constructor & Destructor Documentation

◆ TGCSensitiveDetectorCosmics()

TGCSensitiveDetectorCosmics::TGCSensitiveDetectorCosmics	(	const std::string &	name,
		const std::string &	hitCollectionName
	)

construction/destruction

Definition at line 15 of file TGCSensitiveDetectorCosmics.cxx.

   : G4VSensitiveDetector( name )
   , m_momMag(0)
   , m_globalTime(0)
   , m_myTGCHitColl( hitCollectionName )
 {
   m_muonHelper = TgcHitIdHelper::GetHelper();
 }

◆ ~TGCSensitiveDetectorCosmics()

TGCSensitiveDetectorCosmics::~TGCSensitiveDetectorCosmics ( )

inline

Definition at line 82 of file TGCSensitiveDetectorCosmics.h.

82 {}

Member Function Documentation

◆ FRIEND_TEST() [1/2]

TGCSensitiveDetectorCosmics::FRIEND_TEST	(	TGCSensitiveDetectorCosmicstest	,
		Initialize
	)

private

◆ FRIEND_TEST() [2/2]

TGCSensitiveDetectorCosmics::FRIEND_TEST	(	TGCSensitiveDetectorCosmicstest	,
		ProcessHits
	)

private

◆ Initialize()

void TGCSensitiveDetectorCosmics::Initialize ( G4HCofThisEvent * HCE )

finaloverride

member functions

Definition at line 25 of file TGCSensitiveDetectorCosmics.cxx.

 {
   if (!m_myTGCHitColl.isValid()) m_myTGCHitColl = std::make_unique<TGCSimHitCollection>();
   // START OF COSMICS-SPECIFIC CODE
   m_mom = Amg::Vector3D(0.,0.,0.);
   m_globH = Amg::Vector3D(0.,0.,0.);
   // END OF COSMICS-SPECIFIC CODE
 }

◆ ProcessHits()

G4bool TGCSensitiveDetectorCosmics::ProcessHits	(	G4Step *	aStep,
		G4TouchableHistory *	ROHist
	)

finaloverride

Definition at line 34 of file TGCSensitiveDetectorCosmics.cxx.

                                                                                  {
  
   G4Track* track = aStep->GetTrack();
  
   if (track->GetDefinition()->GetPDGCharge() == 0.0) {
     if (track->GetDefinition()!=G4Geantino::GeantinoDefinition()) return true;
     else if (track->GetDefinition()==G4ChargedGeantino::ChargedGeantinoDefinition()) return true;
   }
   const G4TouchableHistory* touchHist = static_cast<const G4TouchableHistory*>(aStep->GetPreStepPoint()->GetTouchable());
   G4ThreeVector           position  = aStep->GetPreStepPoint()->GetPosition();
   const G4AffineTransform trans     = track->GetTouchable()->GetHistory()->GetTopTransform();
  
   // fields for the TGC identifier construction
   std::string stationName;
   int stationEta(0);
   int stationPhi(0);
   int gasGap = 0;
  
   // TGC hit information
   double globalTime        = aStep->GetPreStepPoint()->GetGlobalTime();
   Amg::Vector3D localPosition = Amg::Hep3VectorToEigen( trans.TransformPoint(position) );
   G4ThreeVector direcos    = aStep->GetPreStepPoint()->GetMomentumDirection();
   Amg::Vector3D localDireCos  = Amg::Hep3VectorToEigen( trans.TransformAxis(direcos) );
  
   // START OF COSMICS-SPECIFIC CODE
   // global coordinates
   G4ThreeVector globVrtx = aStep->GetPreStepPoint()->GetPosition();
  
   // distance of the hit from (0,0,0) vertex - calculated from the PreStepPoint (approximation)
   double dist = globVrtx.mag();
   double inv_lightspeed = 1. / CLHEP::c_light;
   double tOrigin = dist * inv_lightspeed;
  
   G4int trackid = aStep->GetTrack()->GetTrackID();
   m_currVertex = Amg::Hep3VectorToEigen(aStep->GetTrack()->GetVertexPosition());
  
   // for cosmics: only primary muon tracks - track momentum when first entering the spectrometer (one muon per event)
   if ((m_currVertex != m_vertex) && (trackid == 1)) {
     // after calculationg the momentum magnidude, normalize it
     m_mom = Amg::Hep3VectorToEigen(track->GetMomentum());
     m_momMag = m_mom.mag();
     m_mom.normalize();
     // the direction of the primary mu is used to calculate the t0, the position ot the t0, m_globH, is ONE for a track
     Amg::Vector3D globVrtxFix = Amg::Hep3VectorToEigen( globVrtx );
     double AlphaGlobal = -1*(globVrtxFix[0]*m_mom[0] + globVrtxFix[1]*m_mom[1] + globVrtxFix[2]*m_mom[2])/(m_mom[0]*m_mom[0] + m_mom[1]*m_mom[1] + m_mom[2]*m_mom[2]);
     m_globH = globVrtxFix + AlphaGlobal*m_mom;
     // G4cout << "COSMICS MAIN TRACK IN THE TGC!" << G4endl;
   }
   double globalDist = sqrt((m_globH[0] - globVrtx[0])*(m_globH[0] - globVrtx[0]) +
                            (m_globH[1] - globVrtx[1])*(m_globH[1] - globVrtx[1]) +
                            (m_globH[2] - globVrtx[2])*(m_globH[2] - globVrtx[2]));
   double tof = globalDist * inv_lightspeed;
   // END OF COSMICS-SPECIFIC CODE
  
   // scan geometry tree to identify hit channel
   int zside(0);
   for (int i=touchHist->GetHistoryDepth();i>=0;i--) {
  
     std::string::size_type npos;
     std::string volName = touchHist->GetVolume(i)->GetName();
  
     // stationName and stationPhi
     if ((npos = volName.find("station")) != std::string::npos) {
  
       stationName   = volName.substr(0,npos-2);
       int volCopyNo = touchHist->GetVolume(i)->GetCopyNo();
       if (volCopyNo > 0) {
         zside = 1;
       } else {
         zside = -1;
       }
       if (stationName.compare(2,1, "F") == 0) {
  
         stationPhi    = (abs(volCopyNo%100)-1)*3;
         if (abs(volCopyNo/100) > 3) {
           stationPhi += abs(volCopyNo/100)-3;
         } else {
           stationPhi += abs(volCopyNo/100);
         }
  
         stationPhi -= 1;
         if (stationPhi <= 0) {
           stationPhi = 24 - stationPhi;
         }
  
       } else if (stationName.compare(2,1,"E") == 0) {
         if (stationName.compare(1,1,"4") == 0) {
  
           stationPhi = (abs(volCopyNo%100)-1)*3+abs(volCopyNo/100);
  
           if (abs(volCopyNo%100) < 4) {
             stationPhi = stationPhi - 1;
             if (stationPhi <= 0) {
               stationPhi = 21 - stationPhi;
             }
           } else if(abs(volCopyNo%100) < 7) {
             stationPhi = stationPhi - 1 - 1;
           } else {
             stationPhi = stationPhi - 2 - 1;
           }
  
         } else {
  
           stationPhi = (abs(volCopyNo%100)-1)*6+abs(volCopyNo/100);
  
           stationPhi -= 2;
           if (stationPhi <= 0) {
             stationPhi = 48 - stationPhi;
           }
         }
       }
  
     // stationEta
     } else if ((npos = volName.find("tgccomponent")) != std::string::npos) {
       int volCopyNo = abs(touchHist->GetVolume(i)->GetCopyNo());
       stationEta = zside*volCopyNo%100;
       if (volCopyNo > 1000) { // stationPhi overridden by the number assigned by MuonGeoModel
         stationPhi = volCopyNo/1000;
       }
  
     // gasGap
     } else if ((npos = volName.find("Gas Volume Layer")) != std::string::npos) {
       int volCopyNo = touchHist->GetVolume(i)->GetCopyNo();
       int iStation = atoi(stationName.substr(1,1).c_str());
       if (zside < 0) {
         if (iStation == 1)
           gasGap = 3-(volCopyNo-3)/4;
         else
           gasGap = 2-(volCopyNo-3)/4;
       } else {
 //        if (iStation == 1)
           gasGap = (volCopyNo-3)/4+1;
 //        else
 //          gasGap = (volCopyNo-3)/4+1;
       }
     } else if ((npos = volName.find("TGCGas")) != std::string::npos) {
  
       int volCopyNo = touchHist->GetVolume(i)->GetCopyNo();
  
       if (volCopyNo != 0)
         gasGap = volCopyNo;
     }
   }
  
   //construct the hit identifier
   HitID TGCid = m_muonHelper->BuildTgcHitId(stationName,
                                           stationPhi,
                                           stationEta,
                                           gasGap);
   //m_muonHelper->Print(TGCid);
   // START OF COSMICS-SPECIFIC CODE
   m_vertex = Amg::Hep3VectorToEigen(aStep->GetTrack()->GetVertexPosition());
   // if the track m_vertex is far from (0,0,0), takes the tof, otherwise take the "usual" g4 globalTime
   ((((m_vertex.mag()) < 100) || ((fabs(globalTime - tOrigin)) < 0.1) ) ? (m_globalTime  = globalTime) : (m_globalTime = tof));
   // if m_globalTime  != globalTime and m_globalTime != tof in the output, this is due to multiple hits
   // before founding the good one (small approximation)
   // END OF COSMICS-SPECIFIC CODE
  
   // construct new mdt hit
   TrackHelper trHelp(aStep->GetTrack());
   m_myTGCHitColl->Emplace(TGCid,
                         m_globalTime,
                         localPosition,
                         localDireCos,
                         trHelp.GenerateParticleLink(),
                         aStep->GetTotalEnergyDeposit(),
                         aStep->GetStepLength());
   return true;
 }