Gabriele Cosmo
261 lines
8.1 KiB
C++
261 lines
8.1 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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// G4IonCoulombScatteringModel.cc
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// -------------------------------------------------------------------
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//
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// GEANT4 Class header file
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//
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// File name: G4IonCoulombScatteringModel
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//
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// Author: Cristina Consolandi
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//
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// Creation date: 05.10.2010 from G4eCoulombScatteringModel
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// & G4CoulombScatteringModel
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//
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// Class Description:
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// Single Scattering Model for
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// for protons, alpha and heavy Ions
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//
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// Reference:
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// M.J. Boschini et al. "Nuclear and Non-Ionizing Energy-Loss
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// for Coulomb ScatteredParticles from Low Energy up to Relativistic
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// Regime in Space Radiation Environment"
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// Accepted for publication in the Proceedings of the ICATPP Conference
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// on Cosmic Rays for Particle and Astroparticle Physics, Villa Olmo, 7-8
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// October, 2010, to be published by World Scientific (Singapore).
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//
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// Available for downloading at:
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// http://arxiv.org/abs/1011.4822
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//
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// -------------------------------------------------------------------
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//
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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#include "G4IonCoulombScatteringModel.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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#include "G4Proton.hh"
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#include "G4ProductionCutsTable.hh"
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#include "G4NucleiProperties.hh"
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#include "G4UnitsTable.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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using namespace std;
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G4IonCoulombScatteringModel::G4IonCoulombScatteringModel(const G4String& nam)
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: G4VEmModel(nam),
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cosThetaMin(1.0),
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isInitialised(false)
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{
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fNistManager = G4NistManager::Instance();
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theParticleTable = G4ParticleTable::GetParticleTable();
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theProton = G4Proton::Proton();
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pCuts=0;
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currentMaterial = 0;
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currentElement = 0;
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currentCouple = 0;
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lowEnergyLimit = 100*eV;
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recoilThreshold = 0.*eV;
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heavycorr =0;
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particle = 0;
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mass=0;
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currentMaterialIndex = -1;
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ioncross = new G4IonCoulombCrossSection();
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4IonCoulombScatteringModel::~G4IonCoulombScatteringModel()
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{ delete ioncross;}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4IonCoulombScatteringModel::Initialise(const G4ParticleDefinition* p,
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const G4DataVector& )
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{
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SetupParticle(p);
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currentCouple = 0;
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currentMaterialIndex = -1;
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cosThetaMin = cos(PolarAngleLimit());
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ioncross->Initialise(p,cosThetaMin);
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pCuts = G4ProductionCutsTable::GetProductionCutsTable()->GetEnergyCutsVector(3);
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if(!isInitialised) {
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isInitialised = true;
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fParticleChange = GetParticleChangeForGamma();
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4IonCoulombScatteringModel::ComputeCrossSectionPerAtom(
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const G4ParticleDefinition* p,
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G4double kinEnergy,
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G4double Z,
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G4double,
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G4double cutEnergy,
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G4double)
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{
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SetupParticle(p);
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G4double xsec =0.0;
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if(kinEnergy < lowEnergyLimit) return xsec;
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DefineMaterial(CurrentCouple());
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G4int iz = G4int(Z);
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//from lab to pCM & mu_rel of effective particle
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ioncross->SetupKinematic(kinEnergy, cutEnergy,iz);
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ioncross->SetupTarget(Z, kinEnergy, heavycorr);
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xsec = ioncross->NuclearCrossSection();
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//cout<< "..........xsec "<<G4BestUnit(xsec,"Surface") <<endl;
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return xsec;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4IonCoulombScatteringModel::SampleSecondaries(
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std::vector<G4DynamicParticle*>* fvect,
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const G4MaterialCutsCouple* couple,
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const G4DynamicParticle* dp,
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G4double cutEnergy,
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G4double)
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{
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G4double kinEnergy = dp->GetKineticEnergy();
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if(kinEnergy < lowEnergyLimit) return;
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DefineMaterial(couple);
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SetupParticle(dp->GetDefinition());
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// Choose nucleus
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currentElement = SelectRandomAtom(couple,particle,
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kinEnergy,cutEnergy,kinEnergy);
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G4double Z = currentElement->GetZ();
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G4int iz = G4int(Z);
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G4int ia = SelectIsotopeNumber(currentElement);
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G4double m2 = G4NucleiProperties::GetNuclearMass(ia, iz);
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G4double xsec= ComputeCrossSectionPerAtom(particle,kinEnergy, Z,
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kinEnergy, cutEnergy, kinEnergy) ;
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if(xsec == 0.0)return;
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//scattering angle, z1 == (1-cost)
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G4double z1 = ioncross->SampleCosineTheta();
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if(z1 <= 0.0) { return; }
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G4double cost = 1.0 - z1;
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G4double sint = sqrt(z1*(1.0 + cost));
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G4double phi = twopi * G4UniformRand();
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// kinematics in the Lab system
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G4double etot = kinEnergy + mass;
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G4double mom2= kinEnergy*(kinEnergy+2.0*mass);
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G4double ptot = sqrt(mom2);
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//CM particle 1
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G4double bet = ptot/(etot + m2);
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G4double gam = 1.0/sqrt((1.0 - bet)*(1.0 + bet));
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//CM
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G4double momCM2= ioncross->GetMomentum2();
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G4double momCM =std::sqrt(momCM2);
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//energy & momentum after scattering of incident particle
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G4double pxCM = momCM*sint*cos(phi);
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G4double pyCM = momCM*sint*sin(phi);
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G4double pzCM = momCM*cost;
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G4double eCM = sqrt(momCM2 + mass*mass);
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//CM--->Lab
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G4ThreeVector v1(pxCM , pyCM, gam*(pzCM + bet*eCM));
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G4ThreeVector dir = dp->GetMomentumDirection();
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G4ThreeVector newDirection = v1.unit();
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newDirection.rotateUz(dir);
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fParticleChange->ProposeMomentumDirection(newDirection);
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// recoil.......................................
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G4double trec =(1.0 - cost)* m2*(etot*etot - mass*mass )/
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(mass*mass + m2*m2+ 2.*m2*etot);
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G4double finalT = kinEnergy - trec;
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if(finalT <= lowEnergyLimit) {
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trec = kinEnergy;
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finalT = 0.0;
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}
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fParticleChange->SetProposedKineticEnergy(finalT);
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G4double tcut = recoilThreshold;
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if(pCuts) { tcut= std::max(tcut,(*pCuts)[currentMaterialIndex]);
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//G4cout<<" tcut eV "<<tcut/eV<<endl;
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}
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if(trec > tcut) {
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G4ParticleDefinition* ion = theParticleTable->GetIon(iz, ia, 0.0);
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G4double plab = sqrt(finalT*(finalT + 2.0*mass));
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G4ThreeVector p2 = (ptot*dir - plab*newDirection).unit();
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G4DynamicParticle* newdp = new G4DynamicParticle(ion, p2, trec);
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fvect->push_back(newdp);
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} else if(trec > 0.0) {
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fParticleChange->ProposeLocalEnergyDeposit(trec);
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fParticleChange->ProposeNonIonizingEnergyDeposit(trec);
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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