Gabriele Cosmo
237 lines
8.1 KiB
C++
237 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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// 16.05.17 V. Grichine first implementation
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#include "G4NeutronElectronElXsc.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4DynamicParticle.hh"
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#include "G4ParticleDefinition.hh"
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#include "G4ParticleTable.hh"
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#include "G4IonTable.hh"
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#include "G4HadTmpUtil.hh"
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#include "G4NistManager.hh"
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// #include "G4Integrator.hh"
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#include "G4PhysicsLogVector.hh"
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#include "G4PhysicsTable.hh"
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#include "G4Neutron.hh"
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#include "G4Electron.hh"
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using namespace std;
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using namespace CLHEP;
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G4NeutronElectronElXsc::G4NeutronElectronElXsc()
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: G4VCrossSectionDataSet("NuElectronCcXsc")
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{
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// neutron magneton squared
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fM = neutron_mass_c2; // neutron mass
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fM2 = fM*fM;
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fme = electron_mass_c2;
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fme2 = fme*fme;
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fMv2 = 0.7056*GeV*GeV;
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fee = fme;
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fee2 = fee*fee;
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fAm = 0.001;
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fCofXsc = pi*fine_structure_const*fine_structure_const*hbarc*hbarc;
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fCofXsc *= 3.6481; // neutron Fm^2(0)
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fCofXsc /= fM*fM;
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// G4cout<<"fCofXsc = "<<fCofXsc*GeV/cm2<<" cm2/GeV"<<G4endl;
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// G4cout<<"hbarc = "<<hbarc/MeV/fermi<<" MeV*fermi"<<G4endl;
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fCutEnergy = 0.; // default value
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fEnergyBin = 200;
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fMinEnergy = 1.*MeV;
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fMaxEnergy = 10000.*GeV;
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fEnergyXscVector = new G4PhysicsLogVector(fMinEnergy, fMaxEnergy, fEnergyBin);
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for( G4int iTkin = 0; iTkin < fEnergyBin; iTkin++) fEnergyXscVector->PutValue(iTkin, fXscArray[iTkin]*microbarn);
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fBiasingFactor = 1.;
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// Initialise();
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}
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G4NeutronElectronElXsc::~G4NeutronElectronElXsc()
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{
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if( fEnergyXscVector )
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{
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delete fEnergyXscVector;
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fEnergyXscVector = 0;
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}
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}
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//////////////////////////////////////////////////////
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//
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// For neutrons in the precalculated energy interval
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G4bool
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G4NeutronElectronElXsc::IsElementApplicable( const G4DynamicParticle* aPart, G4int, const G4Material*)
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{
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G4bool result = false;
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G4String pName = aPart->GetDefinition()->GetParticleName();
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G4double Tkin = aPart->GetKineticEnergy();
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if( pName == "neutron" &&
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Tkin >= fMinEnergy &&
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Tkin <= fMaxEnergy ) result = true;
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return result;
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}
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//////////////////////////////////////////////////
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void G4NeutronElectronElXsc::Initialise()
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{
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G4int iTkin;
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G4double Tkin, rosxsc, xsc, delta, err=1.e-5;
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const G4ThreeVector mDir = G4ThreeVector(0.,0.,1.);
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const G4ParticleDefinition* pD = G4Neutron::Neutron();
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G4Material* mat = G4NistManager::Instance()->FindOrBuildMaterial("G4_H");
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G4DynamicParticle dP;
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for( iTkin = 0; iTkin < fEnergyBin; iTkin++)
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{
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Tkin = fEnergyXscVector->GetLowEdgeEnergy(iTkin);
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dP = G4DynamicParticle(pD, mDir, Tkin);
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rosxsc = GetRosenbluthXsc(&dP, 1, mat);
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fEnergyXscVector->PutValue(iTkin, rosxsc); // xscV.PutValue(evt, rosxsc); //
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xsc= fEnergyXscVector->Value(Tkin); // xsc= xscV.GetLowEdgeEnergy(evt); //
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delta = 0.5*std::abs( (rosxsc-xsc) )/(rosxsc+xsc);
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if(delta > err) G4cout<<Tkin/GeV<<" GeV, rosxsc = "<<rosxsc/microbarn<<"umb, v-xsc = "<<xsc<<" umb"<<G4endl;
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}
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return;
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}
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////////////////////////////////////////////////////
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G4double G4NeutronElectronElXsc::
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GetElementCrossSection(const G4DynamicParticle* aPart, G4int ZZ,
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const G4Material*)
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{
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G4double result = 0., Tkin;
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Tkin = aPart->GetKineticEnergy();
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result = fEnergyXscVector->Value(Tkin);
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result *= ZZ; // incoherent sum over all element electrons
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result *= fBiasingFactor;
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return result;
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}
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////////////////////////////////////////////////////
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//
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// Integration of the Rosenbluth differential xsc
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G4double G4NeutronElectronElXsc::
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GetRosenbluthXsc(const G4DynamicParticle* aPart, G4int ZZ,
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const G4Material*)
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{
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G4double result = 0., momentum;
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fee = aPart->GetTotalEnergy()*fme/fM;
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fee2 = fee*fee;
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momentum = sqrt( fee2 - fme2 );
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fAm = CalculateAm(momentum);
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// G4Integrator<G4NeutronElectronElXsc, G4double(G4NeutronElectronElXsc::*)(G4double)> integral;
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// result = integral.Legendre96( this, &G4NeutronElectronElXsc::XscIntegrand, 0., 1. );
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result *= fCofXsc;
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result *= ZZ; // incoherent sum over all element electrons
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return result;
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}
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/////////////////////////////////////////
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//
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// Rosenbluth relation in the neutron rest frame,
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// x = sin^2(theta/2), theta is the electron scattering angle
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// Magnetic form factor in the dipole approximation.
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G4double G4NeutronElectronElXsc::XscIntegrand(G4double x)
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{
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G4double result = 1., q2, znq2, znf, znf2, znf4;
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znq2 = 1. + 2.*fee*x/fM;
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q2 = 4.*fee2*x/znq2;
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znf = 1 + q2/fMv2;
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znf2 = znf*znf;
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znf4 = znf2*znf2;
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result /= ( x + fAm )*znq2*znq2*znf4;
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result *= ( 1 - x )/( 1 + q2/4./fM2 ) + 2.*x;
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return result;
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}
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//////////////////////////////////////////////////////////
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//
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// Rosenbluth xsc in microbarn from 1*MeV to 10*Tev, 200 points
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const G4double G4NeutronElectronElXsc::fXscArray[200] = {
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1.52681, 1.54903, 1.57123, 1.59341, 1.61556, 1.63769, 1.6598, 1.68189, 1.70396,
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1.72601, 1.74805, 1.77007, 1.79208, 1.81407, 1.83605, 1.85801, 1.87997, 1.90192,
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1.92385, 1.94578, 1.96771, 1.98962, 2.01154, 2.03345, 2.05535, 2.07725, 2.09915,
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2.12105, 2.14295, 2.16485, 2.18675, 2.20865, 2.23055, 2.25244, 2.27433, 2.29621,
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2.31807, 2.33992, 2.36173, 2.38351, 2.40524, 2.42691, 2.4485, 2.47, 2.49138,
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2.51262, 2.53369, 2.55457, 2.57524, 2.59565, 2.61577, 2.63559, 2.65505, 2.67414,
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2.69281, 2.71104, 2.72881, 2.74607, 2.76282, 2.77903, 2.79467, 2.80974, 2.82422,
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2.83811, 2.85139, 2.86408, 2.87616, 2.88764, 2.89854, 2.90885, 2.91859, 2.92777,
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2.93641, 2.94453, 2.95213, 2.95924, 2.96588, 2.97207, 2.97782, 2.98316, 2.98811,
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2.99268, 2.9969, 3.00078, 3.00435, 3.00761, 3.01059, 3.01331, 3.01578, 3.01801,
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3.02003, 3.02185, 3.02347, 3.02491, 3.02619, 3.02732, 3.0283, 3.02915, 3.02988,
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3.03049, 3.03099, 3.03139, 3.03169, 3.03191, 3.03203, 3.03208, 3.03205, 3.03195,
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3.03177, 3.03152, 3.0312, 3.03081, 3.03034, 3.0298, 3.02919, 3.02849, 3.02771,
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3.02684, 3.02588, 3.02482, 3.02365, 3.02237, 3.02097, 3.01943, 3.01775, 3.0159,
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3.01389, 3.01169, 3.00929, 3.00666, 3.00379, 3.00065, 2.99722, 2.99347, 2.98936,
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2.98487, 2.97996, 2.97459, 2.9687, 2.96226, 2.9552, 2.94748, 2.93903, 2.92977,
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2.91965, 2.90858, 2.89649, 2.88329, 2.86889, 2.85321, 2.83615, 2.81764, 2.7976,
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2.77594, 2.7526, 2.72754, 2.70071, 2.67209, 2.64171, 2.60957, 2.57575, 2.54031,
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2.50336, 2.46504, 2.42548, 2.38484, 2.34328, 2.30099, 2.2581, 2.21478, 2.17115,
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2.12735, 2.08345, 2.03954, 1.99569, 1.95191, 1.90825, 1.86471, 1.82129, 1.77799,
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1.7348, 1.69171, 1.64869, 1.60575, 1.56286, 1.52, 1.47718, 1.43437, 1.39157,
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1.34877, 1.30596, 1.26314, 1.22031, 1.17746, 1.13459, 1.0917, 1.04879, 1.00585,
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0.962892, 0.919908 };
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