DDG4/plugins/Geant4CaloSmearShowerModel.cpp

0001 //==========================================================================
0002 //  AIDA Detector description implementation
0003 //--------------------------------------------------------------------------
0004 // Copyright (C) Organisation europeenne pour la Recherche nucleaire (CERN)
0005 // All rights reserved.
0006 //
0007 // For the licensing terms see $DD4hepINSTALL/LICENSE.
0008 // For the list of contributors see $DD4hepINSTALL/doc/CREDITS.
0009 //
0010 // Author     : M.Frank
0011 //
0012 //==========================================================================
0013 //
0014 // Please note:
0015 //
0016 // These shower parametrizations is a generalized form of the Geant4 example:
0017 // <geant4-source-dir>/examples/extended/parameterisations/Par02
0018 //
0019 //==========================================================================
0020
0021 // Framework include files
0022 #include <DDG4/Geant4FastSimShowerModel.inl.h>
0023 #include <DDG4/Geant4FastSimSpot.h>
0024 #include <DDG4/Geant4Random.h>
0025
0026 // Geant4 include files
0027 #include <G4SystemOfUnits.hh>
0028 #include <G4FastStep.hh>
0029
0030 /// Namespace for the AIDA detector description toolkit
0031 namespace dd4hep  {
0032
0033   /// Namespace for the Geant4 based simulation part of the AIDA detector description toolkit
0034   namespace sim  {
0035
0036     ///===================================================================================================
0037     ///
0038     ///  Par02 electromagnetic shower model (e+, e-)
0039     ///
0040     ///===================================================================================================
0041
0042     /// Configuration structure for the fast simulation shower model Geant4FSShowerModel<par02_em_model>
0043     class calo_smear_model  {
0044     public:
0045       G4FastSimHitMaker hitMaker          { };
0046       double            StocasticEnergyResolution { -1e0 };
0047       double            ConstantEnergyResolution  { -1e0 };
0048       double            NoiseEnergyResolution     { -1e0 };
0049
0050       double resolution(double momentum)   const    {
0051         double res = -1e0;
0052         double mom = momentum/CLHEP::GeV;
0053         if ( this->StocasticEnergyResolution > 0 &&
0054              this->ConstantEnergyResolution  > 0 &&
0055              this->NoiseEnergyResolution > 0 )    {
0056           res = std::sqrt(std::pow( this->StocasticEnergyResolution / std::sqrt( mom ), 2 ) +  // stochastic
0057                           std::pow( this->ConstantEnergyResolution, 2 ) +                      // constant
0058                           std::pow( this->NoiseEnergyResolution / mom, 2 ) );                  // noise
0059         }
0060         else if ( this->StocasticEnergyResolution > 0 &&
0061                   this->ConstantEnergyResolution > 0 )    {
0062           res = std::sqrt(std::pow( this->StocasticEnergyResolution / std::sqrt( mom ), 2 ) +  // stochastic
0063                           std::pow( this->ConstantEnergyResolution, 2 ) );                     // constant
0064         }
0065         else if ( this->StocasticEnergyResolution > 0 )    {
0066           res = this->StocasticEnergyResolution / std::sqrt( mom );                            // stochastic
0067         }
0068         else if ( this->ConstantEnergyResolution > 0 )    {
0069           res = this->ConstantEnergyResolution;                                                // constant
0070         }
0071         return res;
0072       }
0073
0074       double smearEnergy(double mom)   const  {
0075         double resolution = this->resolution(mom);
0076         double smeared    = mom;
0077         if ( resolution > 0e0 )  {
0078           for( smeared = -1e0; smeared < 0e0; ) {  // Ensure that the resulting value is not negative
0079             smeared = mom * Geant4Random::instance()->gauss(1e0, resolution);
0080           }
0081         }
0082         return smeared;
0083       }
0084     };
0085
0086     /// Declare optional properties from embedded structure
0087     template <>
0088     void Geant4FSShowerModel<calo_smear_model>::initialize()     {
0089       declareProperty("StocasticResolution", locals.StocasticEnergyResolution );
0090       declareProperty("ConstantResolution", locals.ConstantEnergyResolution );
0091       declareProperty("NoiseResolution", locals.NoiseEnergyResolution );
0092     }
0093
0094     /// Sensitive detector construction callback. Called at "ConstructSDandField()"
0095     template <>
0096     void Geant4FSShowerModel<calo_smear_model>::constructSensitives(Geant4DetectorConstructionContext* ctxt)   {
0097       this->Geant4FastSimShowerModel::constructSensitives(ctxt);
0098     }
0099
0100     /// User callback to model the particle/energy shower
0101     template <>
0102     void Geant4FSShowerModel<calo_smear_model>::modelShower(const G4FastTrack& track, G4FastStep& step)   {
0103       auto* primary = track.GetPrimaryTrack();
0104       // Kill the parameterised particle:
0105       this->killParticle(step, primary->GetKineticEnergy(), 0e0);
0106       //-----------------------------------------------------
0107       G4FastHit hit;
0108       Geant4FastSimSpot spot(&hit, &track);
0109       G4ThreeVector     position = spot.trackPosition();
0110       double            deposit  = spot.kineticEnergy();
0111
0112       hit.SetPosition(spot.trackPosition());
0113       // Consider only primary tracks and smear according to the parametrized resolution
0114       // ELSE: simply set the value of the (initial) energy of the particle is deposited in the step
0115       if ( !spot.primary->GetParentID() ) {
0116         deposit = locals.smearEnergy(deposit);
0117       }
0118       hit.SetEnergy(deposit);
0119       step.ProposeTotalEnergyDeposited(deposit);
0120       this->locals.hitMaker.make(hit, track);
0121     }
0122
0123     typedef Geant4FSShowerModel<calo_smear_model> Geant4CaloSmearShowerModel;
0124   }
0125 }
0126
0127 #include <DDG4/Factories.h>
0128 DECLARE_GEANT4ACTION_NS(dd4hep::sim,Geant4CaloSmearShowerModel)
0129