Gabriele Cosmo
206 lines
7.2 KiB
C++
206 lines
7.2 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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// $Id: G4PEEffectModel.cc,v 1.8 2009/04/09 18:41:18 vnivanch Exp $
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// GEANT4 tag $Name: geant4-09-03 $
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//
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// -------------------------------------------------------------------
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//
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// GEANT4 Class file
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//
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//
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// File name: G4PEEffectModel
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//
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// Author: Vladimir Ivanchenko on base of Michel Maire code
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//
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// Creation date: 21.03.2005
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//
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// Modifications:
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//
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// 04.12.05 : SetProposedKineticEnergy(0.) for the killed photon (mma)
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// 20.02.09 : Added initialisation of deexcitation flag and method
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// CrossSectionPerVolume instead of mfp (V.Ivanchenko)
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//
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// Class Description:
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//
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// -------------------------------------------------------------------
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//
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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#include "G4PEEffectModel.hh"
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#include "G4Electron.hh"
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#include "G4Gamma.hh"
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#include "Randomize.hh"
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#include "G4DataVector.hh"
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#include "G4ParticleChangeForGamma.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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using namespace std;
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G4PEEffectModel::G4PEEffectModel(const G4ParticleDefinition*,
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const G4String& nam)
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: G4VEmModel(nam),isInitialized(false)
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{
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theGamma = G4Gamma::Gamma();
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theElectron = G4Electron::Electron();
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fminimalEnergy = 1.0*eV;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4PEEffectModel::~G4PEEffectModel()
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{}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4PEEffectModel::Initialise(const G4ParticleDefinition*,
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const G4DataVector&)
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{
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// always false before the run
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SetDeexcitationFlag(false);
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if (isInitialized) return;
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fParticleChange = GetParticleChangeForGamma();
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isInitialized = true;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo.....
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G4double G4PEEffectModel::ComputeCrossSectionPerAtom(const G4ParticleDefinition*,
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G4double energy,
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G4double Z, G4double,
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G4double, G4double)
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{
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G4double* SandiaCof = G4SandiaTable::GetSandiaCofPerAtom((G4int)Z, energy);
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G4double energy2 = energy*energy;
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G4double energy3 = energy*energy2;
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G4double energy4 = energy2*energy2;
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return SandiaCof[0]/energy + SandiaCof[1]/energy2 +
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SandiaCof[2]/energy3 + SandiaCof[3]/energy4;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4PEEffectModel::CrossSectionPerVolume(const G4Material* material,
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const G4ParticleDefinition*,
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G4double energy,
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G4double, G4double)
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{
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G4double* SandiaCof =
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material->GetSandiaTable()->GetSandiaCofForMaterial(energy);
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G4double energy2 = energy*energy;
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G4double energy3 = energy*energy2;
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G4double energy4 = energy2*energy2;
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return SandiaCof[0]/energy + SandiaCof[1]/energy2 +
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SandiaCof[2]/energy3 + SandiaCof[3]/energy4;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4PEEffectModel::SampleSecondaries(std::vector<G4DynamicParticle*>* fvect,
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const G4MaterialCutsCouple* couple,
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const G4DynamicParticle* aDynamicPhoton,
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G4double,
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G4double)
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{
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const G4Material* aMaterial = couple->GetMaterial();
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G4double energy = aDynamicPhoton->GetKineticEnergy();
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G4ParticleMomentum PhotonDirection = aDynamicPhoton->GetMomentumDirection();
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// select randomly one element constituing the material.
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const G4Element* anElement = SelectRandomAtom(aMaterial,theGamma,energy);
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//
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// Photo electron
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//
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// Select atomic shell
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G4int nShells = anElement->GetNbOfAtomicShells();
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G4int i = 0;
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while ((i<nShells) && (energy<anElement->GetAtomicShell(i))) i++;
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// no shell available
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if (i == nShells) return;
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G4double bindingEnergy = anElement->GetAtomicShell(i);
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G4double ElecKineEnergy = energy - bindingEnergy;
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if (ElecKineEnergy > fminimalEnergy)
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{
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// direction of the photo electron
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//
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G4double cosTeta = ElecCosThetaDistribution(ElecKineEnergy);
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G4double sinTeta = sqrt(1.-cosTeta*cosTeta);
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G4double Phi = twopi * G4UniformRand();
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G4double dirx = sinTeta*cos(Phi),diry = sinTeta*sin(Phi),dirz = cosTeta;
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G4ThreeVector ElecDirection(dirx,diry,dirz);
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ElecDirection.rotateUz(PhotonDirection);
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//
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G4DynamicParticle* aParticle = new G4DynamicParticle (
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theElectron,ElecDirection, ElecKineEnergy);
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fvect->push_back(aParticle);
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}
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fParticleChange->SetProposedKineticEnergy(0.);
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fParticleChange->ProposeTrackStatus(fStopAndKill);
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fParticleChange->ProposeLocalEnergyDeposit(bindingEnergy);
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4PEEffectModel::ElecCosThetaDistribution(G4double kineEnergy)
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{
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// Compute Theta distribution of the emitted electron, with respect to the
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// incident Gamma.
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// The Sauter-Gavrila distribution for the K-shell is used.
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//
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G4double costeta = 1.;
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G4double gamma = 1. + kineEnergy/electron_mass_c2;
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if (gamma > 5.) return costeta;
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G4double beta = sqrt(gamma*gamma-1.)/gamma;
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G4double b = 0.5*gamma*(gamma-1.)*(gamma-2);
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G4double rndm,term,greject,grejsup;
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if (gamma < 2.) grejsup = gamma*gamma*(1.+b-beta*b);
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else grejsup = gamma*gamma*(1.+b+beta*b);
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do { rndm = 1.-2*G4UniformRand();
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costeta = (rndm+beta)/(rndm*beta+1.);
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term = 1.-beta*costeta;
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greject = (1.-costeta*costeta)*(1.+b*term)/(term*term);
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} while(greject < G4UniformRand()*grejsup);
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return costeta;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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