Gabriele Cosmo
243 lines
7.3 KiB
C++
243 lines
7.3 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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//
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// -------------------------------------------------------------------
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//
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//
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// GEANT4 Class header file
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//
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//
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// File name: G4WentzelOKandVIxSection
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//
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// Authors: V.Ivanchenko and O.Kadri
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//
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// Creation date: 21.05.2010
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//
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// Modifications:
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//
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//
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// Class Description:
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//
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// Implementation of the computation of total and transport cross sections,
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// sample scattering angle for the single scattering case.
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// to be used by single and multiple scattering models. References:
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// 1) G.Wentzel, Z. Phys. 40 (1927) 590.
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// 2) J.M. Fernandez-Varea et al., NIM B73 (1993) 447.
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//
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// -------------------------------------------------------------------
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//
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#ifndef G4WentzelOKandVIxSection_h
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#define G4WentzelOKandVIxSection_h 1
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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#include "globals.hh"
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#include "G4Material.hh"
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#include "G4Element.hh"
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#include "G4ElementVector.hh"
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#include "G4NistManager.hh"
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#include "G4NuclearFormfactorType.hh"
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#include "G4ThreeVector.hh"
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#include "G4Pow.hh"
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class G4ParticleDefinition;
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class G4ScreeningMottCrossSection;
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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class G4WentzelOKandVIxSection
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{
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public:
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explicit G4WentzelOKandVIxSection(G4bool combined=true);
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virtual ~G4WentzelOKandVIxSection();
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void Initialise(const G4ParticleDefinition*, G4double CosThetaLim);
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void SetupParticle(const G4ParticleDefinition*);
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// return cos(ThetaMax) for msc and cos(thetaMin) for single scattering
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// cut = DBL_MAX means no scattering off electrons
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virtual G4double SetupKinematic(G4double kinEnergy, const G4Material* mat);
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G4double SetupTarget(G4int Z, G4double cut);
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G4double ComputeTransportCrossSectionPerAtom(G4double CosThetaMax);
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G4ThreeVector& SampleSingleScattering(G4double CosThetaMin,
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G4double CosThetaMax,
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G4double elecRatio);
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G4double ComputeSecondTransportMoment(G4double CosThetaMax);
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inline G4double ComputeNuclearCrossSection(G4double CosThetaMin,
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G4double CosThetaMax);
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inline G4double ComputeElectronCrossSection(G4double CosThetaMin,
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G4double CosThetaMax);
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inline void SetTargetMass(G4double value);
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inline G4double GetMomentumSquare() const;
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inline G4double GetCosThetaNuc() const;
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inline G4double GetCosThetaElec() const;
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// hide assignment operator
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G4WentzelOKandVIxSection & operator=
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(const G4WentzelOKandVIxSection &right) = delete;
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G4WentzelOKandVIxSection(const G4WentzelOKandVIxSection&) = delete;
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protected:
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void ComputeMaxElectronScattering(G4double cut);
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void InitialiseA();
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inline G4double FlatFormfactor(G4double x);
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const G4ParticleDefinition* theProton;
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const G4ParticleDefinition* theElectron;
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const G4ParticleDefinition* thePositron;
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const G4ParticleDefinition* particle = nullptr;
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const G4Material* currentMaterial = nullptr;
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G4NistManager* fNistManager;
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G4Pow* fG4pow;
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G4ScreeningMottCrossSection* fMottXSection = nullptr;
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G4ThreeVector temp;
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// single scattering parameters
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G4double coeff;
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G4double cosTetMaxElec = 1.0;
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G4double cosTetMaxNuc = 1.0;
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// for the combined mode it is cos(thetaMax)
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// for single scattering it is cos(thetaMin)
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G4double cosThetaMax = 1.0;
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G4double chargeSquare = 0.0;
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G4double charge3 = 0.0;
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G4double spin = 0.0;
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G4double mass = 0.0;
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G4double tkin = 0.0;
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G4double mom2 = 0.0;
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G4double momCM2 = 0.0;
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G4double invbeta2 = 1.0;
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G4double kinFactor = 1.0;
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G4double etag = DBL_MAX;
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G4double ecut = DBL_MAX;
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// target
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G4double targetMass;
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G4double screenZ = 0.0;
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G4double formfactA = 0.0;
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G4double factorA2 = 0.0;
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G4double factB = 0.0;
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G4double factD = 0.0;
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G4double fMottFactor = 1.0;
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G4double gam0pcmp = 1.0;
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G4double pcmp2 = 1.0;
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// integer parameters
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G4int targetZ = 0;
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G4int nwarnings = 0;
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G4NuclearFormfactorType fNucFormfactor = fExponentialNF;
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G4bool isCombined;
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static G4double ScreenRSquareElec[100];
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static G4double ScreenRSquare[100];
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static G4double FormFactor[100];
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};
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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inline void G4WentzelOKandVIxSection::SetTargetMass(G4double value)
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{
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targetMass = value;
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factD = std::sqrt(mom2)/value;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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inline G4double G4WentzelOKandVIxSection::GetMomentumSquare() const
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{
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return mom2;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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inline G4double G4WentzelOKandVIxSection::GetCosThetaNuc() const
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{
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return cosTetMaxNuc;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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inline G4double G4WentzelOKandVIxSection::GetCosThetaElec() const
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{
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return cosTetMaxElec;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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inline G4double
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G4WentzelOKandVIxSection::ComputeNuclearCrossSection(G4double cosTMin,
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G4double cosTMax)
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{
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return targetZ*kinFactor*fMottFactor*(cosTMin - cosTMax)/
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((1.0 - cosTMin + screenZ)*(1.0 - cosTMax + screenZ));
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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inline G4double
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G4WentzelOKandVIxSection::ComputeElectronCrossSection(G4double cosTMin,
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G4double cosTMax)
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{
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G4double cost1 = std::max(cosTMin,cosTetMaxElec);
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G4double cost2 = std::max(cosTMax,cosTetMaxElec);
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return (cost1 <= cost2) ? 0.0 : kinFactor*fMottFactor*(cost1 - cost2)/
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((1.0 - cost1 + screenZ)*(1.0 - cost2 + screenZ));
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}
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inline G4double G4WentzelOKandVIxSection::FlatFormfactor(G4double x)
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{
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return 3.0*(std::sin(x) - x*std::cos(x))/(x*x*x);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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#endif
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