Gabriele Cosmo
193 lines
7.5 KiB
C++
193 lines
7.5 KiB
C++
//
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// ********************************************************************
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// * License and Disclaimer *
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// * *
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// * The Geant4 software is copyright of the Copyright Holders of *
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// * the Geant4 Collaboration. It is provided under the terms and *
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// * conditions of the Geant4 Software License, included in the file *
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// * LICENSE and available at http://cern.ch/geant4/license . These *
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// * include a list of copyright holders. *
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// * *
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// * Neither the authors of this software system, nor their employing *
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// * institutes,nor the agencies providing financial support for this *
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// * work make any representation or warranty, express or implied, *
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// * regarding this software system or assume any liability for its *
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// * use. Please see the license in the file LICENSE and URL above *
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// * for the full disclaimer and the limitation of liability. *
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// * *
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// * This code implementation is the result of the scientific and *
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// * technical work of the GEANT4 collaboration. *
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// * By using, copying, modifying or distributing the software (or *
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// * any work based on the software) you agree to acknowledge its *
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// * use in resulting scientific publications, and indicate your *
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// * acceptance of all terms of the Geant4 Software license. *
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// ********************************************************************
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//
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// Author: Alexei Sytov
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// Co-author: Gianfranco Paterno (testing)
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// Using the key points of G4BaierKatkov and developments of V.V. Tikhomirov,
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// partially described in L. Bandiera et al. Eur. Phys. J. C 82, 699 (2022)
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#ifndef G4CoherentPairProduction_h
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#define G4CoherentPairProduction_h 1
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#include "G4VDiscreteProcess.hh"
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#include <vector>
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#include <CLHEP/Units/SystemOfUnits.h>
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#include <CLHEP/Units/PhysicalConstants.h>
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#include <CLHEP/Vector/TwoVector.h>
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#include "G4ChannelingFastSimCrystalData.hh"
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#include "G4LogicalVolume.hh"
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#include "G4ParticleTable.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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class G4CoherentPairProduction : public G4VDiscreteProcess
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{
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public:
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G4CoherentPairProduction(const G4String& processName = "cpp",
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G4ProcessType aType = fElectromagnetic);
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~G4CoherentPairProduction() = default;
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G4VParticleChange* PostStepDoIt(const G4Track&, const G4Step&) override;
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G4bool IsApplicable(const G4ParticleDefinition& aPD) override
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{
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return(aPD.GetParticleName() == "gamma");
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}
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// print documentation in html format
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void ProcessDescription(std::ostream&) const override;
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///special functions
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void Input(const G4Material* crystal,
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const G4String &lattice)
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{Input(crystal,lattice,"");}
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void Input(const G4Material* crystal,
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const G4String &lattice,
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const G4String &filePath);
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// an option to use crystal data already created outside this class
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void Input(const G4ChannelingFastSimCrystalData* crystalData);
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///activate incoherent scattering
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///(standard gamma conversion should be switched off in physics list)
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void ActivateIncoherentScattering(){fIncoherentScattering = true;}
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G4ChannelingFastSimCrystalData* GetCrystalData() {return fCrystalData;}
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///get cuts
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// minimal energy for non-zero cross section
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G4double ModelMinPrimaryEnergy() { return fLowEnergyLimit;}
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G4double GetHighAngleLimit() {return fHighAngleLimit;}
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G4double GetPPKineticEnergyCut() {return fPPKineticEnergyCut;}
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/// get the number of pairs in sampling of Baier-Katkov Integral
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/// (MC integration by e+- energy and angles <=> e+- momentum)
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G4int GetSamplingPairsNumber(){return fNMCPairs;}
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/// get the number of particle angles 1/gamma in pair production
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/// defining the width of the angular distribution of pair sampling
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/// in the Baier-Katkov Integral
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G4double GetChargeParticleAngleFactor(){return fChargeParticleAngleFactor;}
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/// get number of trajectory steps of a single particle (e- or e+)
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G4double GetNTrajectorySteps(){return fNTrajectorySteps;}
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/// get effective radiation length
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/// (due to coherent process of pair production)
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/// simulated for the current photon
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G4double GetEffectiveLrad(){return fEffectiveLrad;}
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///get the name of G4Region in which the model is applicable
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G4String GetG4RegionName() {return fG4RegionName;}
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///set cuts
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void SetLowEnergyLimit(G4double energy){fLowEnergyLimit=energy;}
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void SetHighAngleLimit(G4double angle) {fHighAngleLimit=angle;}
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void SetPPKineticEnergyCut(G4double kineticEnergyCut) {fPPKineticEnergyCut=kineticEnergyCut;}
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/// set the number of pairs in sampling of Baier-Katkov Integral
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/// (MC integration by e+- energy and angles <=> e+- momentum)
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void SetSamplingPairsNumber(G4int nPairs){fNMCPairs = nPairs;}
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/// set the number of particle angles 1/gamma in pair production
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/// defining the width of the angular distribution of pair sampling
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/// in the Baier-Katkov Integral
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void SetChargeParticleAngleFactor(G4double chargeParticleAngleFactor)
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{fChargeParticleAngleFactor = chargeParticleAngleFactor;}
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/// set number of trajectory steps of a single particle (e- or e+)
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void SetNTrajectorySteps(G4int nTrajectorySteps)
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{fNTrajectorySteps = nTrajectorySteps;}
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///set the name of G4Region in which the model is applicable
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void SetG4RegionName(const G4String& nameG4Region){fG4RegionName=nameG4Region;}
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G4double GetMeanFreePath(const G4Track& aTrack,
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G4double,
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G4ForceCondition* condition) override;
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private:
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G4int FindVectorIndex(std::vector<G4double> &myvector, G4double value);
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G4ChannelingFastSimCrystalData* fCrystalData{nullptr};
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//collection of etotal
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std::vector <CLHEP::Hep2Vector> fullVectorEtotal;
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//collection of x
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std::vector <CLHEP::Hep2Vector> fullVectorX;
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//collection of y
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std::vector <CLHEP::Hep2Vector> fullVectorY;
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//collection of tx
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std::vector <CLHEP::Hep2Vector> fullVectorTX;
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//collection of tx
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std::vector <CLHEP::Hep2Vector> fullVectorTY;
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//the vector of the discrete CDF of the production of sampling e+e- pairs
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//(in reality per distance along the photon direction)
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std::vector <G4double> fPairProductionCDFdz;
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G4double fLowEnergyLimit = 1*CLHEP::GeV;
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G4double fHighAngleLimit = 50*CLHEP::mrad;
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///minimal kinetic energy of a charged particle produced
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G4double fPPKineticEnergyCut = 1*CLHEP::MeV;
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///Monte Carlo statistics of e+- pair sampling in Baier-Katkov for 1 photon
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G4int fNMCPairs = 150;
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G4double fChargeParticleAngleFactor = 4; // number of particle angles 1/gamma:
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// more fChargeParticleAngleFactor => higher paramParticleAngle
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///number of trajectory steps of a single particle (e- or e+)
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G4int fNTrajectorySteps=250;
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///effective radiation length (due to coherent process of pair production)
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G4double fEffectiveLrad = 0.;
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///the name of G4Region in which the model is applicable
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G4String fG4RegionName = "Crystal";
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///charged particle mass
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const G4double fMass = CLHEP::electron_mass_c2;
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///flag of simulation of incoherent scattering
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G4bool fIncoherentScattering = false;
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};
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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#endif
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