Gabriele Cosmo
132 lines
4.9 KiB
C++
132 lines
4.9 KiB
C++
//
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// ********************************************************************
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// * DISCLAIMER *
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// * *
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// * The following disclaimer summarizes all the specific disclaimers *
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// * of contributors to this software. The specific disclaimers,which *
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// * govern, are listed with their locations in: *
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// * http://cern.ch/geant4/license *
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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. *
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// * *
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// * This code implementation is the intellectual property of the *
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// * GEANT4 collaboration. *
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// * By copying, distributing or modifying the Program (or any work *
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// * based on the Program) you indicate your acceptance of this *
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// * statement, and all its terms. *
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// ********************************************************************
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//
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// neutron_hp -- source file
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// J.P. Wellisch, Nov-1996
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// A prototype of the low energy neutron transport model.
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//
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#include "G4NeutronHPElasticData.hh"
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#include "G4Neutron.hh"
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#include "G4ElementTable.hh"
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#include "G4NeutronHPData.hh"
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G4bool G4NeutronHPElasticData::IsApplicable(const G4DynamicParticle*aP, const G4Element*anE)
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{
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G4bool result = true;
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G4double eKin = aP->GetKineticEnergy();
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if(eKin>20*MeV||aP->GetDefinition()!=G4Neutron::Neutron()) result = false;
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return result;
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}
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G4NeutronHPElasticData::G4NeutronHPElasticData()
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{
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BuildPhysicsTable(*G4Neutron::Neutron());
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}
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G4NeutronHPElasticData::~G4NeutronHPElasticData()
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{
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delete theCrossSections;
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}
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void G4NeutronHPElasticData::BuildPhysicsTable(const G4ParticleDefinition& aP)
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{
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if(&aP!=G4Neutron::Neutron())
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G4Exception("Attempt to use NeutronHP data for particles other than neutrons!!!");
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size_t numberOfElements = G4Element::GetNumberOfElements();
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theCrossSections = new G4PhysicsTable( numberOfElements );
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// make a PhysicsVector for each element
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static const G4ElementTable *theElementTable = G4Element::GetElementTable();
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for( size_t i=0; i<numberOfElements; ++i )
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{
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G4PhysicsVector* physVec = G4NeutronHPData::
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Instance()->MakePhysicsVector((*theElementTable)[i], this);
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theCrossSections->push_back(physVec);
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}
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}
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void G4NeutronHPElasticData::DumpPhysicsTable(const G4ParticleDefinition& aP)
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{
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if(&aP!=G4Neutron::Neutron())
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G4Exception("Attempt to use NeutronHP data for particles other than neutrons!!!");
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// G4cout << "G4NeutronHPElasticData::DumpPhysicsTable still to be implemented"<<G4endl;
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}
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#include "G4Nucleus.hh"
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#include "G4NucleiPropertiesTable.hh"
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#include "G4Neutron.hh"
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#include "G4Electron.hh"
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G4double G4NeutronHPElasticData::
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GetCrossSection(const G4DynamicParticle* aP, const G4Element*anE, G4double aT)
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{
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G4double result = 0;
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G4bool outOfRange;
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G4int index = anE->GetIndex();
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// prepare neutron
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G4double eKinetic = aP->GetKineticEnergy();
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G4ReactionProduct theNeutron( aP->GetDefinition() );
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theNeutron.SetMomentum( aP->GetMomentum() );
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theNeutron.SetKineticEnergy( eKinetic );
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// prepare thermal nucleus
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G4Nucleus aNuc;
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G4double eps = 0.0001;
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G4double theA = anE->GetN();
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G4double theZ = anE->GetZ();
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G4double eleMass;
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eleMass = ( G4NucleiPropertiesTable::GetAtomicMass(theZ+eps, theA+eps)-
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theZ*G4Electron::ElectronDefinition()->GetPDGMass()
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) / G4Neutron::Neutron()->GetPDGMass();
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G4ReactionProduct boosted;
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G4double aXsection;
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// MC integration loop
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G4int counter = 0;
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G4double buffer = 0;
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G4int size = G4int(G4std::max(10., aT/60*kelvin));
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G4ThreeVector neutronVelocity = 1./G4Neutron::Neutron()->GetPDGMass()*theNeutron.GetMomentum();
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G4double neutronVMag = neutronVelocity.mag();
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while(counter == 0 || abs(buffer-result/counter) > 0.03*buffer)
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{
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if(counter) buffer = result/counter;
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while (counter<size)
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{
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counter ++;
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G4ReactionProduct aThermalNuc = aNuc.GetThermalNucleus(eleMass, aT);
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boosted.Lorentz(theNeutron, aThermalNuc);
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G4double theEkin = boosted.GetKineticEnergy();
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aXsection = (*((*theCrossSections)(index))).GetValue(theEkin, outOfRange);
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// velocity correction.
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G4ThreeVector targetVelocity = 1./aThermalNuc.GetMass()*aThermalNuc.GetMomentum();
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aXsection *= (targetVelocity+neutronVelocity).mag()/neutronVMag;
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result += aXsection;
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}
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size += size;
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}
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result /= counter;
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return result;
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}
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