Gabriele Cosmo
656 lines
18 KiB
C++
656 lines
18 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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// Physics model class G4DiffuseElasticV2
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//
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//
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// G4 Model: optical diffuse elastic scattering with 4-momentum balance
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//
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// 24-May-07 V. Grichine
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//
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// 21.10.15 V. Grichine
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// Bug fixed in BuildAngleTable, improving accuracy for
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// angle bins at high energies > 50 GeV for pions.
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//
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// 24.11.17 W. Pokorski, code cleanup and performance improvements
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//
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#include "G4DiffuseElasticV2.hh"
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#include "G4ParticleTable.hh"
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#include "G4ParticleDefinition.hh"
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#include "G4IonTable.hh"
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#include "G4NucleiProperties.hh"
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#include "Randomize.hh"
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#include "G4Integrator.hh"
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#include "globals.hh"
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#include "G4PhysicalConstants.hh"
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#include "G4SystemOfUnits.hh"
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#include "G4Proton.hh"
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#include "G4Neutron.hh"
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#include "G4Deuteron.hh"
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#include "G4Alpha.hh"
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#include "G4PionPlus.hh"
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#include "G4PionMinus.hh"
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#include "G4Element.hh"
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#include "G4ElementTable.hh"
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#include "G4NistManager.hh"
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#include "G4PhysicsTable.hh"
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#include "G4PhysicsLogVector.hh"
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#include "G4PhysicsFreeVector.hh"
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#include "G4Exp.hh"
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#include "G4HadronicParameters.hh"
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/////////////////////////////////////////////////////////////////////////
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//
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G4DiffuseElasticV2::G4DiffuseElasticV2()
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: G4HadronElastic("DiffuseElasticV2"), fParticle(0)
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{
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SetMinEnergy( 0.01*MeV );
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SetMaxEnergy( G4HadronicParameters::Instance()->GetMaxEnergy() );
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verboseLevel = 0;
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lowEnergyRecoilLimit = 100.*keV;
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lowEnergyLimitQ = 0.0*GeV;
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lowEnergyLimitHE = 0.0*GeV;
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lowestEnergyLimit = 0.0*keV;
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plabLowLimit = 20.0*MeV;
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theProton = G4Proton::Proton();
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theNeutron = G4Neutron::Neutron();
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fEnergyBin = 300; // Increased from the original 200 to have no wider log-energy-bins up to 10 PeV
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fAngleBin = 200;
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fEnergyVector = new G4PhysicsLogVector( theMinEnergy, theMaxEnergy, fEnergyBin );
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fEnergyAngleVector = 0;
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fEnergySumVector = 0;
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fParticle = 0;
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fWaveVector = 0.;
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fAtomicWeight = 0.;
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fAtomicNumber = 0.;
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fNuclearRadius = 0.;
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fBeta = 0.;
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fZommerfeld = 0.;
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fAm = 0.;
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fAddCoulomb = false;
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}
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//////////////////////////////////////////////////////////////////////////////
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//
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// Destructor
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G4DiffuseElasticV2::~G4DiffuseElasticV2()
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{
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if ( fEnergyVector )
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{
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delete fEnergyVector;
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fEnergyVector = 0;
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}
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}
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//////////////////////////////////////////////////////////////////////////////
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//
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// Initialisation for given particle using element table of application
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void G4DiffuseElasticV2::Initialise()
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{
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const G4ElementTable* theElementTable = G4Element::GetElementTable();
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std::size_t jEl, numOfEl = G4Element::GetNumberOfElements();
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for( jEl = 0; jEl < numOfEl; ++jEl) // application element loop
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{
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fAtomicNumber = (*theElementTable)[jEl]->GetZ(); // atomic number
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fAtomicWeight = G4NistManager::Instance()->GetAtomicMassAmu( static_cast< G4int >( fAtomicNumber ) );
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fNuclearRadius = CalculateNuclearRad(fAtomicWeight);
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if( verboseLevel > 0 )
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{
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G4cout<<"G4DiffuseElasticV2::Initialise() the element: "
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<<(*theElementTable)[jEl]->GetName()<<G4endl;
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}
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fElementNumberVector.push_back(fAtomicNumber);
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fElementNameVector.push_back((*theElementTable)[jEl]->GetName());
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BuildAngleTable();
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fEnergyAngleVectorBank.push_back(fEnergyAngleVector);
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fEnergySumVectorBank.push_back(fEnergySumVector);
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}
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return;
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}
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////////////////////////////////////////////////////////////////////////////
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//
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// return differential elastic probability d(probability)/d(t) with
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// Coulomb correction. It is called from BuildAngleTable()
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G4double
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G4DiffuseElasticV2::GetDiffElasticSumProbA( G4double theta )
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{
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G4double sigma, bzero, bzero2, bonebyarg, bonebyarg2, damp, damp2;
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G4double delta, diffuse, gamma;
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G4double e1, e2, bone, bone2;
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// G4double wavek = momentum/hbarc; // wave vector
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// G4double r0 = 1.08*fermi;
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// G4double rad = r0*G4Pow::GetInstance()->A13(A);
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G4double kr = fWaveVector*fNuclearRadius; // wavek*rad;
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G4double kr2 = kr*kr;
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G4double krt = kr*theta;
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bzero = BesselJzero(krt);
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bzero2 = bzero*bzero;
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bone = BesselJone(krt);
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bone2 = bone*bone;
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bonebyarg = BesselOneByArg(krt);
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bonebyarg2 = bonebyarg*bonebyarg;
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if ( fParticle == theProton )
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{
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diffuse = 0.63*fermi;
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gamma = 0.3*fermi;
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delta = 0.1*fermi*fermi;
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e1 = 0.3*fermi;
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e2 = 0.35*fermi;
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}
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else if ( fParticle == theNeutron )
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{
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diffuse = 0.63*fermi;
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gamma = 0.3*fermi;
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delta = 0.1*fermi*fermi;
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e1 = 0.3*fermi;
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e2 = 0.35*fermi;
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}
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else // as proton, if were not defined
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{
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diffuse = 0.63*fermi;
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gamma = 0.3*fermi;
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delta = 0.1*fermi*fermi;
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e1 = 0.3*fermi;
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e2 = 0.35*fermi;
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}
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G4double lambda = 15; // 15 ok
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// G4double kgamma = fWaveVector*gamma; // wavek*delta;
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G4double kgamma = lambda*(1.-G4Exp(-fWaveVector*gamma/lambda)); // wavek*delta;
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if( fAddCoulomb ) // add Coulomb correction
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{
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G4double sinHalfTheta = std::sin(0.5*theta);
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G4double sinHalfTheta2 = sinHalfTheta*sinHalfTheta;
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kgamma += 0.5*fZommerfeld/kr/(sinHalfTheta2+fAm); // correction at J0()
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}
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G4double kgamma2 = kgamma*kgamma;
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// G4double dk2t = delta*fWaveVector*fWaveVector*theta; // delta*wavek*wavek*theta;
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// G4double dk2t2 = dk2t*dk2t;
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// G4double pikdt = pi*fWaveVector*diffuse*theta;// pi*wavek*diffuse*theta;
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G4double pikdt = lambda*(1. - G4Exp( -pi*fWaveVector*diffuse*theta/lambda ) ); // wavek*delta;
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damp = DampFactor( pikdt );
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damp2 = damp*damp;
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G4double mode2k2 = ( e1*e1 + e2*e2 )*fWaveVector*fWaveVector;
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G4double e2dk3t = -2.*e2*delta*fWaveVector*fWaveVector*fWaveVector*theta;
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sigma = kgamma2;
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// sigma += dk2t2;
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sigma *= bzero2;
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sigma += mode2k2*bone2;
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sigma += e2dk3t*bzero*bone;
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// sigma += kr2*(1 + 8.*fZommerfeld*fZommerfeld/kr2)*bonebyarg2; // correction at J1()/()
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sigma += kr2*bonebyarg2; // correction at J1()/()
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sigma *= damp2; // *rad*rad;
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return sigma;
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}
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////////////////////////////////////////////////////////////////////////////
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//
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// return differential elastic probability 2*pi*sin(theta)*d(probability)/d(omega)
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G4double
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G4DiffuseElasticV2::GetIntegrandFunction( G4double alpha )
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{
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G4double result;
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result = GetDiffElasticSumProbA(alpha) * 2 * CLHEP::pi * std::sin(alpha);
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return result;
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}
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/////////////////////////////////////////////////////////////////////////////
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///////////////////// Table preparation and reading ////////////////////////
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////////////////////////////////////////////////////////////////////////////
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//
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// Return inv momentum transfer -t > 0 from initialisation table
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G4double G4DiffuseElasticV2::SampleInvariantT( const G4ParticleDefinition* aParticle, G4double p,
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G4int Z, G4int A)
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{
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fParticle = aParticle;
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G4double m1 = fParticle->GetPDGMass(), t;
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G4double totElab = std::sqrt(m1*m1+p*p);
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G4double mass2 = G4NucleiProperties::GetNuclearMass(A, Z);
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G4LorentzVector lv1(p,0.0,0.0,totElab);
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G4LorentzVector lv(0.0,0.0,0.0,mass2);
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lv += lv1;
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G4ThreeVector bst = lv.boostVector();
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lv1.boost(-bst);
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G4ThreeVector p1 = lv1.vect();
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G4double momentumCMS = p1.mag();
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if( aParticle == theNeutron)
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{
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G4double Tmax = NeutronTuniform( Z );
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G4double pCMS2 = momentumCMS*momentumCMS;
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G4double Tkin = std::sqrt(pCMS2+m1*m1)-m1;
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if( Tkin <= Tmax )
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{
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t = 4.*pCMS2*G4UniformRand();
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return t;
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}
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}
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t = SampleTableT( aParticle, momentumCMS, G4double(Z), G4double(A) ); // sample theta in cms
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return t;
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}
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///////////////////////////////////////////////////////
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G4double G4DiffuseElasticV2::NeutronTuniform(G4int Z)
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{
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G4double elZ = G4double(Z);
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elZ -= 1.;
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G4double Tkin = 12.*G4Exp(-elZ/10.) + 1.;
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return Tkin;
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}
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////////////////////////////////////////////////////////////////////////////
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//
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// Return inv momentum transfer -t > 0 from initialisation table
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G4double G4DiffuseElasticV2::SampleTableT( const G4ParticleDefinition* aParticle, G4double p,
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G4double Z, G4double A)
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{
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G4double alpha = SampleTableThetaCMS( aParticle, p, Z, A); // sample theta in cms
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G4double t = 2*p*p*( 1 - std::cos(alpha) ); // -t !!!
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return t;
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}
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////////////////////////////////////////////////////////////////////////////
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//
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// Return scattering angle2 sampled in cms according to precalculated table.
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G4double
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G4DiffuseElasticV2::SampleTableThetaCMS(const G4ParticleDefinition* particle,
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G4double momentum, G4double Z, G4double A)
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{
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std::size_t iElement;
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G4int iMomentum;
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unsigned long iAngle = 0;
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G4double randAngle, position, theta1, theta2, E1, E2, W1, W2, W;
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G4double m1 = particle->GetPDGMass();
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for(iElement = 0; iElement < fElementNumberVector.size(); iElement++)
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{
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if( std::fabs(Z - fElementNumberVector[iElement]) < 0.5) break;
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}
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if ( iElement == fElementNumberVector.size() )
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{
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InitialiseOnFly(Z,A); // table preparation, if needed
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}
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fEnergyAngleVector = fEnergyAngleVectorBank[iElement];
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fEnergySumVector = fEnergySumVectorBank[iElement];
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G4double kinE = std::sqrt(momentum*momentum + m1*m1) - m1;
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iMomentum = G4int(fEnergyVector->FindBin(kinE,1000) + 1);
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position = (*(*fEnergySumVector)[iMomentum])[0]*G4UniformRand();
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for(iAngle = 0; iAngle < fAngleBin; ++iAngle)
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{
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if (position > (*(*fEnergySumVector)[iMomentum])[iAngle]) break;
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}
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if (iMomentum == fEnergyBin -1 || iMomentum == 0 ) // the table edges
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{
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randAngle = GetScatteringAngle(iMomentum, iAngle, position);
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}
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else // kinE inside between energy table edges
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{
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theta2 = GetScatteringAngle(iMomentum, iAngle, position);
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E2 = fEnergyVector->Energy(iMomentum);
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iMomentum--;
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theta1 = GetScatteringAngle(iMomentum, iAngle, position);
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E1 = fEnergyVector->Energy(iMomentum);
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W = 1.0/(E2 - E1);
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W1 = (E2 - kinE)*W;
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W2 = (kinE - E1)*W;
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randAngle = W1*theta1 + W2*theta2;
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}
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if(randAngle < 0.) randAngle = 0.;
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return randAngle;
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}
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//////////////////////////////////////////////////////////////////////////////
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//
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// Initialisation for given particle on fly using new element number
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void G4DiffuseElasticV2::InitialiseOnFly(G4double Z, G4double A)
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{
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fAtomicNumber = Z; // atomic number
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fAtomicWeight = G4NistManager::Instance()->GetAtomicMassAmu( static_cast< G4int >( Z ) );
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fNuclearRadius = CalculateNuclearRad(fAtomicWeight);
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if( verboseLevel > 0 )
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{
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G4cout<<"G4DiffuseElasticV2::InitialiseOnFly() the element with Z = "
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<<Z<<"; and A = "<<A<<G4endl;
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}
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fElementNumberVector.push_back(fAtomicNumber);
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BuildAngleTable();
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fEnergyAngleVectorBank.push_back(fEnergyAngleVector);
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fEnergySumVectorBank.push_back(fEnergySumVector);
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return;
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}
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///////////////////////////////////////////////////////////////////////////////
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//
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// Build for given particle and element table of momentum, angle probability.
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// For the moment in lab system.
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void G4DiffuseElasticV2::BuildAngleTable()
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{
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G4double partMom, kinE, a = 0., z = fParticle->GetPDGCharge(), m1 = fParticle->GetPDGMass();
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G4double alpha1, alpha2, alphaMax, alphaCoulomb, delta = 0., sum = 0.;
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G4Integrator<G4DiffuseElasticV2,G4double(G4DiffuseElasticV2::*)(G4double)> integral;
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fEnergyAngleVector = new std::vector<std::vector<G4double>*>;
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fEnergySumVector = new std::vector<std::vector<G4double>*>;
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for( G4int i = 0; i < fEnergyBin; ++i)
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{
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kinE = fEnergyVector->Energy(i);
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partMom = std::sqrt( kinE*(kinE + 2*m1) );
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fWaveVector = partMom/hbarc;
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G4double kR = fWaveVector*fNuclearRadius;
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G4double kRmax = 18.6; // 10.6; 10.6, 18, 10.174; ~ 3 maxima of J1 or 15., 25.
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G4double kRcoul = 1.9; // 1.2; 1.4, 2.5; // on the first slope of J1
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alphaMax = kRmax/kR;
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if ( alphaMax >= CLHEP::pi ) alphaMax = CLHEP::pi; // vmg21.10.15
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alphaCoulomb = kRcoul/kR;
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if( z )
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{
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a = partMom/m1; // beta*gamma for m1
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fBeta = a/std::sqrt(1+a*a);
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fZommerfeld = CalculateZommerfeld( fBeta, z, fAtomicNumber);
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fAm = CalculateAm( partMom, fZommerfeld, fAtomicNumber);
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fAddCoulomb = true;
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}
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std::vector<G4double>* angleVector = new std::vector<G4double>(fAngleBin);
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std::vector<G4double>* sumVector = new std::vector<G4double>(fAngleBin);
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G4double delth = alphaMax/fAngleBin;
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sum = 0.;
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for(G4int j = (G4int)fAngleBin-1; j >= 0; --j)
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{
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alpha1 = delth*j;
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alpha2 = alpha1 + delth;
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if( fAddCoulomb && ( alpha2 < alphaCoulomb)) fAddCoulomb = false;
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delta = integral.Legendre10(this, &G4DiffuseElasticV2::GetIntegrandFunction, alpha1, alpha2);
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sum += delta;
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(*angleVector)[j] = alpha1;
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(*sumVector)[j] = sum;
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}
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fEnergyAngleVector->push_back(angleVector);
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fEnergySumVector->push_back(sumVector);
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}
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return;
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}
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/////////////////////////////////////////////////////////////////////////////////
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//
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//
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G4double
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G4DiffuseElasticV2::GetScatteringAngle( G4int iMomentum, unsigned long iAngle, G4double position )
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{
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G4double x1, x2, y1, y2, randAngle = 0;
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if( iAngle == 0 )
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{
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randAngle = (*(*fEnergyAngleVector)[iMomentum])[iAngle];
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}
|
|
else
|
|
{
|
|
if ( iAngle >= (*fEnergyAngleVector)[iMomentum]->size() )
|
|
{
|
|
iAngle = (*fEnergyAngleVector)[iMomentum]->size() - 1;
|
|
}
|
|
|
|
y1 = (*(*fEnergySumVector)[iMomentum])[iAngle-1];
|
|
y2 = (*(*fEnergySumVector)[iMomentum])[iAngle];
|
|
|
|
x1 = (*(*fEnergyAngleVector)[iMomentum])[iAngle-1];
|
|
x2 = (*(*fEnergyAngleVector)[iMomentum])[iAngle];
|
|
|
|
if ( x1 == x2 ) randAngle = x2;
|
|
else
|
|
{
|
|
if ( y1 == y2 ) randAngle = x1 + ( x2 - x1 )*G4UniformRand();
|
|
else
|
|
{
|
|
randAngle = x1 + ( position - y1 )*( x2 - x1 )/( y2 - y1 );
|
|
}
|
|
}
|
|
}
|
|
|
|
return randAngle;
|
|
}
|
|
|
|
|
|
|
|
|
|
////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// Return scattering angle in lab system (target at rest) knowing theta in CMS
|
|
|
|
|
|
|
|
G4double
|
|
G4DiffuseElasticV2::ThetaCMStoThetaLab( const G4DynamicParticle* aParticle,
|
|
G4double tmass, G4double thetaCMS)
|
|
{
|
|
const G4ParticleDefinition* theParticle = aParticle->GetDefinition();
|
|
G4double m1 = theParticle->GetPDGMass();
|
|
G4LorentzVector lv1 = aParticle->Get4Momentum();
|
|
G4LorentzVector lv(0.0,0.0,0.0,tmass);
|
|
|
|
lv += lv1;
|
|
|
|
G4ThreeVector bst = lv.boostVector();
|
|
|
|
lv1.boost(-bst);
|
|
|
|
G4ThreeVector p1 = lv1.vect();
|
|
G4double ptot = p1.mag();
|
|
|
|
G4double phi = G4UniformRand()*twopi;
|
|
G4double cost = std::cos(thetaCMS);
|
|
G4double sint;
|
|
|
|
if( cost >= 1.0 )
|
|
{
|
|
cost = 1.0;
|
|
sint = 0.0;
|
|
}
|
|
else if( cost <= -1.0)
|
|
{
|
|
cost = -1.0;
|
|
sint = 0.0;
|
|
}
|
|
else
|
|
{
|
|
sint = std::sqrt((1.0-cost)*(1.0+cost));
|
|
}
|
|
if (verboseLevel>1)
|
|
{
|
|
G4cout << "cos(tcms)=" << cost << " std::sin(tcms)=" << sint << G4endl;
|
|
}
|
|
G4ThreeVector v1(sint*std::cos(phi),sint*std::sin(phi),cost);
|
|
v1 *= ptot;
|
|
G4LorentzVector nlv1(v1.x(),v1.y(),v1.z(),std::sqrt(ptot*ptot + m1*m1));
|
|
|
|
nlv1.boost(bst);
|
|
|
|
G4ThreeVector np1 = nlv1.vect();
|
|
|
|
G4double thetaLab = np1.theta();
|
|
|
|
return thetaLab;
|
|
}
|
|
////////////////////////////////////////////////////////////////////////////
|
|
//
|
|
// Return scattering angle in CMS system (target at rest) knowing theta in Lab
|
|
|
|
|
|
|
|
G4double
|
|
G4DiffuseElasticV2::ThetaLabToThetaCMS( const G4DynamicParticle* aParticle,
|
|
G4double tmass, G4double thetaLab)
|
|
{
|
|
const G4ParticleDefinition* theParticle = aParticle->GetDefinition();
|
|
G4double m1 = theParticle->GetPDGMass();
|
|
G4double plab = aParticle->GetTotalMomentum();
|
|
G4LorentzVector lv1 = aParticle->Get4Momentum();
|
|
G4LorentzVector lv(0.0,0.0,0.0,tmass);
|
|
|
|
lv += lv1;
|
|
|
|
G4ThreeVector bst = lv.boostVector();
|
|
|
|
G4double phi = G4UniformRand()*twopi;
|
|
G4double cost = std::cos(thetaLab);
|
|
G4double sint;
|
|
|
|
if( cost >= 1.0 )
|
|
{
|
|
cost = 1.0;
|
|
sint = 0.0;
|
|
}
|
|
else if( cost <= -1.0)
|
|
{
|
|
cost = -1.0;
|
|
sint = 0.0;
|
|
}
|
|
else
|
|
{
|
|
sint = std::sqrt((1.0-cost)*(1.0+cost));
|
|
}
|
|
if (verboseLevel>1)
|
|
{
|
|
G4cout << "cos(tlab)=" << cost << " std::sin(tlab)=" << sint << G4endl;
|
|
}
|
|
G4ThreeVector v1(sint*std::cos(phi),sint*std::sin(phi),cost);
|
|
v1 *= plab;
|
|
G4LorentzVector nlv1(v1.x(),v1.y(),v1.z(),std::sqrt(plab*plab + m1*m1));
|
|
|
|
nlv1.boost(-bst);
|
|
|
|
G4ThreeVector np1 = nlv1.vect();
|
|
G4double thetaCMS = np1.theta();
|
|
|
|
return thetaCMS;
|
|
}
|
|
|