Gabriele Cosmo
546 lines
17 KiB
C++
546 lines
17 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: G4DNAScreenedRutherfordElasticModel.cc 92074 2015-08-17 07:03:46Z gcosmo $
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//
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#include "G4DNAScreenedRutherfordElasticModel.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4DNAMolecularMaterial.hh"
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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using namespace std;
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4DNAScreenedRutherfordElasticModel::G4DNAScreenedRutherfordElasticModel(const G4ParticleDefinition*,
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const G4String& nam) :
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G4VEmModel(nam), isInitialised(false)
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{
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// nistwater = G4NistManager::Instance()->FindOrBuildMaterial("G4_WATER");
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fpWaterDensity = 0;
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killBelowEnergy = 9 * eV;
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lowEnergyLimit = 0 * eV;
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intermediateEnergyLimit = 200 * eV; // Switch between two final state models
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highEnergyLimit = 1. * MeV;
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SetLowEnergyLimit(lowEnergyLimit);
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SetHighEnergyLimit(highEnergyLimit);
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verboseLevel = 0;
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// Verbosity scale:
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// 0 = nothing
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// 1 = warning for energy non-conservation
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// 2 = details of energy budget
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// 3 = calculation of cross sections, file openings, sampling of atoms
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// 4 = entering in methods
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if (verboseLevel > 0)
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{
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G4cout << "Screened Rutherford Elastic model is constructed " << G4endl<< "Energy range: "
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<< lowEnergyLimit / eV << " eV - "
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<< highEnergyLimit / MeV << " MeV"
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<< G4endl;
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}
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fParticleChangeForGamma = 0;
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// Selection of computation method
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// We do not recommend "true" usage with the current cumul. proba. settings
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fasterCode = false;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4DNAScreenedRutherfordElasticModel::~G4DNAScreenedRutherfordElasticModel()
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{
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4DNAScreenedRutherfordElasticModel::Initialise(const G4ParticleDefinition* /*particle*/,
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const G4DataVector& /*cuts*/)
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{
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if (verboseLevel > 3)
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G4cout << "Calling G4DNAScreenedRutherfordElasticModel::Initialise()"
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<< G4endl;
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// Energy limits
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if (LowEnergyLimit() < lowEnergyLimit)
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{
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G4cout << "G4DNAScreenedRutherfordElasticModel: low energy limit increased from " <<
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LowEnergyLimit()/eV << " eV to " << lowEnergyLimit/eV << " eV" << G4endl;
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SetLowEnergyLimit(lowEnergyLimit);
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}
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if (HighEnergyLimit() > highEnergyLimit)
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{
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G4cout << "G4DNAScreenedRutherfordElasticModel: high energy limit decreased from " <<
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HighEnergyLimit()/MeV << " MeV to " << highEnergyLimit/MeV << " MeV" << G4endl;
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SetHighEnergyLimit(highEnergyLimit);
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}
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// Constants for final state by Brenner & Zaider
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// March 25th, 2014 - Vaclav Stepan, Sebastien Incerti
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// Added clear for MT
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betaCoeff.clear();
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betaCoeff.push_back(7.51525);
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betaCoeff.push_back(-0.41912);
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betaCoeff.push_back(7.2017E-3);
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betaCoeff.push_back(-4.646E-5);
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betaCoeff.push_back(1.02897E-7);
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deltaCoeff.clear();
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deltaCoeff.push_back(2.9612);
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deltaCoeff.push_back(-0.26376);
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deltaCoeff.push_back(4.307E-3);
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deltaCoeff.push_back(-2.6895E-5);
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deltaCoeff.push_back(5.83505E-8);
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gamma035_10Coeff.clear();
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gamma035_10Coeff.push_back(-1.7013);
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gamma035_10Coeff.push_back(-1.48284);
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gamma035_10Coeff.push_back(0.6331);
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gamma035_10Coeff.push_back(-0.10911);
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gamma035_10Coeff.push_back(8.358E-3);
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gamma035_10Coeff.push_back(-2.388E-4);
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gamma10_100Coeff.clear();
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gamma10_100Coeff.push_back(-3.32517);
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gamma10_100Coeff.push_back(0.10996);
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gamma10_100Coeff.push_back(-4.5255E-3);
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gamma10_100Coeff.push_back(5.8372E-5);
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gamma10_100Coeff.push_back(-2.4659E-7);
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gamma100_200Coeff.clear();
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gamma100_200Coeff.push_back(2.4775E-2);
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gamma100_200Coeff.push_back(-2.96264E-5);
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gamma100_200Coeff.push_back(-1.20655E-7);
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//
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if( verboseLevel>0 )
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{
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G4cout << "Screened Rutherford elastic model is initialized " << G4endl
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<< "Energy range: "
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<< LowEnergyLimit() / eV << " eV - "
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<< HighEnergyLimit() / MeV << " MeV"
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<< G4endl;
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}
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// Initialize water density pointer
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fpWaterDensity = G4DNAMolecularMaterial::Instance()->GetNumMolPerVolTableFor(G4Material::GetMaterial("G4_WATER"));
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if (isInitialised)
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{ return;}
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fParticleChangeForGamma = GetParticleChangeForGamma();
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isInitialised = true;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4DNAScreenedRutherfordElasticModel::CrossSectionPerVolume(const G4Material* material,
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const G4ParticleDefinition* particleDefinition,
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G4double ekin,
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G4double,
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G4double)
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{
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if (verboseLevel > 3)
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G4cout << "Calling CrossSectionPerVolume() of G4DNAScreenedRutherfordElasticModel"
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<< G4endl;
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// Calculate total cross section for model
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G4double sigma=0;
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G4double waterDensity = (*fpWaterDensity)[material->GetIndex()];
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if(waterDensity!= 0.0)
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// if (material == nistwater || material->GetBaseMaterial() == nistwater)
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{
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if (ekin < highEnergyLimit)
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{
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if (ekin < killBelowEnergy) return DBL_MAX;
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G4double z = 10.;
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G4double n = ScreeningFactor(ekin,z);
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G4double crossSection = RutherfordCrossSection(ekin, z);
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sigma = pi * crossSection / (n * (n + 1.));
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}
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if (verboseLevel > 2)
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{
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G4cout << "__________________________________" << G4endl;
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G4cout << "=== G4DNAScreenedRutherfordElasticModel - XS INFO START" << G4endl;
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G4cout << "=== Kinetic energy(eV)=" << ekin/eV << " particle : " << particleDefinition->GetParticleName() << G4endl;
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G4cout << "=== Cross section per water molecule (cm^2)=" << sigma/cm/cm << G4endl;
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G4cout << "=== Cross section per water molecule (cm^-1)=" << sigma*waterDensity/(1./cm) << G4endl;
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// G4cout << " - Cross section per water molecule (cm^-1)=" << sigma*material->GetAtomicNumDensityVector()[1]/(1./cm) << G4endl;
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G4cout << "=== G4DNAScreenedRutherfordElasticModel - XS INFO END" << G4endl;
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}
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}
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return sigma*waterDensity;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4DNAScreenedRutherfordElasticModel::RutherfordCrossSection(G4double k,
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G4double z)
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{
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//
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// e^4 / K + m_e c^2 \^2
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// sigma_Ruth(K) = Z (Z+1) -------------------- | --------------------- |
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// (4 pi epsilon_0)^2 \ K * (K + 2 m_e c^2) /
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//
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// Where K is the electron non-relativistic kinetic energy
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//
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// NIM 155, pp. 145-156, 1978
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G4double length = (e_squared * (k + electron_mass_c2))
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/ (4 * pi * epsilon0 * k * (k + 2 * electron_mass_c2));
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G4double cross = z * (z + 1) * length * length;
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return cross;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4DNAScreenedRutherfordElasticModel::ScreeningFactor(G4double k,
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G4double z)
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{
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//
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// alpha_1 + beta_1 ln(K/eV) constK Z^(2/3)
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// n(T) = -------------------------- -----------------
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// K/(m_e c^2) 2 + K/(m_e c^2)
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//
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// Where K is the electron non-relativistic kinetic energy
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//
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// n(T) > 0 for T < ~ 400 MeV
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//
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// NIM 155, pp. 145-156, 1978
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// Formulae (2) and (5)
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const G4double alpha_1(1.64);
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const G4double beta_1(-0.0825);
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const G4double constK(1.7E-5);
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G4double numerator = (alpha_1 + beta_1 * std::log(k / eV)) * constK
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* std::pow(z, 2. / 3.);
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k /= electron_mass_c2;
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G4double denominator = k * (2 + k);
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G4double value = 0.;
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if (denominator > 0.) value = numerator / denominator;
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return value;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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void G4DNAScreenedRutherfordElasticModel::SampleSecondaries(std::vector<
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G4DynamicParticle*>* /*fvect*/,
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const G4MaterialCutsCouple* /*couple*/,
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const G4DynamicParticle* aDynamicElectron,
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G4double,
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G4double)
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{
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if (verboseLevel > 3)
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{
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G4cout << "Calling SampleSecondaries() of G4DNAScreenedRutherfordElasticModel"
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<< G4endl;
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}
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G4double electronEnergy0 = aDynamicElectron->GetKineticEnergy();
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if (electronEnergy0 < killBelowEnergy)
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{
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fParticleChangeForGamma->SetProposedKineticEnergy(0.);
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fParticleChangeForGamma->ProposeTrackStatus(fStopAndKill);
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fParticleChangeForGamma->ProposeLocalEnergyDeposit(electronEnergy0);
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return;
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}
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G4double cosTheta = 0.;
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if (electronEnergy0>= killBelowEnergy && electronEnergy0 < highEnergyLimit)
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{
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if (electronEnergy0<intermediateEnergyLimit)
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{
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if (verboseLevel > 3) G4cout << "---> Using Brenner & Zaider model" << G4endl;
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cosTheta = BrennerZaiderRandomizeCosTheta(electronEnergy0);
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}
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if (electronEnergy0>=intermediateEnergyLimit)
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{
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if (verboseLevel > 3) G4cout << "---> Using Screened Rutherford model" << G4endl;
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G4double z = 10.;
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cosTheta = ScreenedRutherfordRandomizeCosTheta(electronEnergy0,z);
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}
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G4double phi = 2. * pi * G4UniformRand();
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G4ThreeVector zVers = aDynamicElectron->GetMomentumDirection();
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G4ThreeVector xVers = zVers.orthogonal();
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G4ThreeVector yVers = zVers.cross(xVers);
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G4double xDir = std::sqrt(1. - cosTheta*cosTheta);
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G4double yDir = xDir;
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xDir *= std::cos(phi);
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yDir *= std::sin(phi);
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G4ThreeVector zPrimeVers((xDir*xVers + yDir*yVers + cosTheta*zVers));
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fParticleChangeForGamma->ProposeMomentumDirection(zPrimeVers.unit());
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fParticleChangeForGamma->SetProposedKineticEnergy(electronEnergy0);
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}
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo....
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G4double G4DNAScreenedRutherfordElasticModel::BrennerZaiderRandomizeCosTheta(G4double k)
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{
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// d sigma_el 1 beta(K)
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// ------------ (K) ~ --------------------------------- + ---------------------------------
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// d Omega (1 + 2 gamma(K) - cos(theta))^2 (1 + 2 delta(K) + cos(theta))^2
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//
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// Maximum is < 1/(4 gamma(K)^2) + beta(K)/((2+2delta(K))^2)
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//
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// Phys. Med. Biol. 29 N.4 (1983) 443-447
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// gamma(K), beta(K) and delta(K) are polynomials with coefficients for energy measured in eV
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k /= eV;
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G4double beta = std::exp(CalculatePolynomial(k, betaCoeff));
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G4double delta = std::exp(CalculatePolynomial(k, deltaCoeff));
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G4double gamma;
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if (k > 100.)
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{
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gamma = CalculatePolynomial(k, gamma100_200Coeff);
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// Only in this case it is not the exponent of the polynomial
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}
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else
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{
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if (k > 10)
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{
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gamma = std::exp(CalculatePolynomial(k, gamma10_100Coeff));
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}
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else
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{
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gamma = std::exp(CalculatePolynomial(k, gamma035_10Coeff));
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}
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}
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// ***** Original method
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if (!fasterCode)
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{
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G4double oneOverMax = 1.
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/ (1. / (4. * gamma * gamma) + beta
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/ ((2. + 2. * delta) * (2. + 2. * delta)));
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G4double cosTheta = 0.;
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G4double leftDenominator = 0.;
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G4double rightDenominator = 0.;
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G4double fCosTheta = 0.;
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do
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{
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cosTheta = 2. * G4UniformRand()- 1.;
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leftDenominator = (1. + 2.*gamma - cosTheta);
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rightDenominator = (1. + 2.*delta + cosTheta);
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if ( (leftDenominator * rightDenominator) != 0. )
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{
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fCosTheta = oneOverMax * (1./(leftDenominator*leftDenominator) + beta/(rightDenominator*rightDenominator));
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}
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}
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while (fCosTheta < G4UniformRand());
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return cosTheta;
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}
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// ***** Alternative method using cumulative probability
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if (fasterCode)
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{
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G4double cosTheta = -1;
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G4double cumul = 0;
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G4double value = 0;
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G4double leftDenominator = 0.;
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G4double rightDenominator = 0.;
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// Number of integration steps in the -1,1 range
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G4int iMax=200;
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G4double random = G4UniformRand();
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// Cumulate differential cross section
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for (G4int i=0; i<iMax; i++)
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{
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cosTheta = -1 + i*2./(iMax-1);
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leftDenominator = (1. + 2.*gamma - cosTheta);
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rightDenominator = (1. + 2.*delta + cosTheta);
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if ( (leftDenominator * rightDenominator) != 0. )
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{
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cumul = cumul + (1./(leftDenominator*leftDenominator) + beta/(rightDenominator*rightDenominator));
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}
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}
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// Select cosTheta
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for (G4int i=0; i<iMax; i++)
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{
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cosTheta = -1 + i*2./(iMax-1);
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leftDenominator = (1. + 2.*gamma - cosTheta);
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rightDenominator = (1. + 2.*delta + cosTheta);
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if (cumul !=0 && (leftDenominator * rightDenominator) != 0.)
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value = value + (1./(leftDenominator*leftDenominator) + beta/(rightDenominator*rightDenominator)) / cumul;
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if (random < value) break;
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}
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return cosTheta;
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}
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return 0.;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4DNAScreenedRutherfordElasticModel::CalculatePolynomial(G4double k,
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std::vector<
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G4double>& vec)
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{
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// Sum_{i=0}^{size-1} vector_i k^i
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//
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// Phys. Med. Biol. 29 N.4 (1983) 443-447
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G4double result = 0.;
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size_t size = vec.size();
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while (size > 0)
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{
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size--;
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result *= k;
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result += vec[size];
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}
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return result;
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}
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//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
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G4double G4DNAScreenedRutherfordElasticModel::ScreenedRutherfordRandomizeCosTheta(G4double k,
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G4double z)
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{
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// d sigma_el sigma_Ruth(K)
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// ------------ (K) ~ -----------------------------
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// d Omega (1 + 2 n(K) - cos(theta))^2
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//
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// We extract cos(theta) distributed as (1 + 2 n(K) - cos(theta))^-2
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//
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// Maximum is for theta=0: 1/(4 n(K)^2) (When n(K) is positive, that is always satisfied within the validity of the process)
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//
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// Phys. Med. Biol. 45 (2000) 3171-3194
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// ***** Original method
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if (!fasterCode)
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{
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G4double n = ScreeningFactor(k, z);
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G4double oneOverMax = (4. * n * n);
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G4double cosTheta = 0.;
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G4double fCosTheta;
|
|
|
|
do
|
|
{
|
|
cosTheta = 2. * G4UniformRand()- 1.;
|
|
fCosTheta = (1 + 2.*n - cosTheta);
|
|
if (fCosTheta !=0.) fCosTheta = oneOverMax / (fCosTheta*fCosTheta);
|
|
}
|
|
while (fCosTheta < G4UniformRand());
|
|
|
|
return cosTheta;
|
|
}
|
|
|
|
// ***** Alternative method using cumulative probability
|
|
if (fasterCode)
|
|
{
|
|
|
|
G4double cosTheta = -1;
|
|
G4double cumul = 0;
|
|
G4double value = 0;
|
|
G4double n = ScreeningFactor(k, z);
|
|
G4double fCosTheta;
|
|
|
|
// Number of integration steps in the -1,1 range
|
|
G4int iMax=200;
|
|
|
|
G4double random = G4UniformRand();
|
|
|
|
// Cumulate differential cross section
|
|
for (G4int i=0; i<iMax; i++)
|
|
{
|
|
cosTheta = -1 + i*2./(iMax-1);
|
|
fCosTheta = (1 + 2.*n - cosTheta);
|
|
if (fCosTheta !=0.) cumul = cumul + 1./(fCosTheta*fCosTheta);
|
|
}
|
|
|
|
// Select cosTheta
|
|
for (G4int i=0; i<iMax; i++)
|
|
{
|
|
cosTheta = -1 + i*2./(iMax-1);
|
|
fCosTheta = (1 + 2.*n - cosTheta);
|
|
if (cumul !=0.) value = value + (1./(fCosTheta*fCosTheta)) / cumul;
|
|
if (random < value) break;
|
|
}
|
|
return cosTheta;
|
|
}
|
|
|
|
return 0.;
|
|
}
|
|
|