G4BGGNucleonElasticXS.cc

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// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4BGGNucleonElasticXS
//
// Author:        Vladimir Ivanchenko
//
// Creation date: 13.03.2007
//
// -------------------------------------------------------------------
//
 
#include "G4BGGNucleonElasticXS.hh"
#include "G4SystemOfUnits.hh"
#include "G4ComponentGGHadronNucleusXsc.hh"
#include "G4NucleonNuclearCrossSection.hh"
#include "G4HadronNucleonXsc.hh"
#include "G4NuclearRadii.hh"
#include "G4Proton.hh"
#include "G4Neutron.hh"
#include "G4NistManager.hh"
#include "G4NuclearRadii.hh"
 
#include "G4CrossSectionDataSetRegistry.hh"
 
G4double G4BGGNucleonElasticXS::theGlauberFacP[93] = {0.0};
G4double G4BGGNucleonElasticXS::theCoulombFacP[93] = {0.0};
G4double G4BGGNucleonElasticXS::theGlauberFacN[93] = {0.0};
G4double G4BGGNucleonElasticXS::theCoulombFacN[93] = {0.0};
G4int G4BGGNucleonElasticXS::theA[93] = {0};
 
G4BGGNucleonElasticXS::G4BGGNucleonElasticXS(const G4ParticleDefinition* p)
 : G4VCrossSectionDataSet("BarashenkovGlauberGribov") 
{
  verboseLevel = 0;
  fGlauberEnergy = 91.*GeV;
  fLowEnergy = 14.0*MeV;
  fNucleon = new G4NucleonNuclearCrossSection();
  fGlauber = new G4ComponentGGHadronNucleusXsc();
  fHadron = new G4HadronNucleonXsc();
 
  theProton = G4Proton::Proton();
  isProton = (theProton == p);
  SetForAllAtomsAndEnergies(true);
 
  if (0 == theA[0]) { Initialise(); } 
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4BGGNucleonElasticXS::~G4BGGNucleonElasticXS()
{
  delete fHadron;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4bool 
G4BGGNucleonElasticXS::IsElementApplicable(const G4DynamicParticle*, G4int,
                                           const G4Material*)
{
  return true;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4bool G4BGGNucleonElasticXS::IsIsoApplicable(const G4DynamicParticle*, 
                                              G4int Z, G4int,  
                                              const G4Element*,
                                              const G4Material*)
{
  return (1 == Z);
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4double
G4BGGNucleonElasticXS::GetElementCrossSection(const G4DynamicParticle* dp,
                                              G4int ZZ, const G4Material*)
{
  // this method should be called only for Z > 1
 
  G4double cross = 0.0;
  G4int Z = std::min(ZZ, 92);
  G4double ekin = dp->GetKineticEnergy();
  if(1 == Z) {
    cross = 1.0115*GetIsoCrossSection(dp,1,1);
  } else {
    if(ekin <= fLowEnergy) {
      cross = (isProton) ? theCoulombFacP[Z] : theCoulombFacN[Z];
      cross *= CoulombFactor(ekin, Z);
    } else if(ekin > fGlauberEnergy) {
      cross = (isProton) ? theGlauberFacP[Z] : theGlauberFacN[Z];
      cross *= fGlauber->GetElasticGlauberGribov(dp, Z, theA[Z]);
    } else {
      cross = fNucleon->GetElasticCrossSection(dp, Z);
    }
  }
#ifdef G4VERBOSE
  if (verboseLevel > 1) {
    G4cout << "G4BGGNucleonElasticXS::GetElementCrossSection  for "
           << dp->GetDefinition()->GetParticleName()
           << "  Ekin(GeV)= " << dp->GetKineticEnergy()/CLHEP::GeV
           << " in nucleus Z= " << Z << "  A= " << theA[Z]
           << " XS(b)= " << cross/barn 
           << G4endl;
  }
#endif
  return cross;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4double
G4BGGNucleonElasticXS::GetIsoCrossSection(const G4DynamicParticle* dp, 
                                          G4int, G4int A, 
                                          const G4Isotope*,
                                          const G4Element*,
                                          const G4Material*)
{
  // this method should be called only for Z = 1
  fHadron->HadronNucleonXscNS(dp->GetDefinition(), theProton, 
                              dp->GetKineticEnergy());
  G4double cross = A*fHadron->GetElasticHadronNucleonXsc();
 
#ifdef G4VERBOSE
  if (verboseLevel > 1) {
    G4cout << "G4BGGNucleonElasticXS::GetIsoCrossSection  for "
           << dp->GetDefinition()->GetParticleName()
           << "  Ekin(GeV)= " << dp->GetKineticEnergy()/CLHEP::GeV
           << " in nucleus  Z=1  A=" << A
           << " XS(b)= " << cross/barn 
           << G4endl;
  }
#endif
  return cross;
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BGGNucleonElasticXS::BuildPhysicsTable(const G4ParticleDefinition& p)
{
  if(&p == theProton || &p == G4Neutron::Neutron()) {
    isProton = (theProton == &p);
 
  } else {
    G4ExceptionDescription ed;
    ed << "This BGG cross section is applicable only to nucleons and not to " 
       << p.GetParticleName() << G4endl; 
    G4Exception("G4BGGNucleonElasticXS::BuildPhysicsTable", "had001", 
                FatalException, ed);
  }
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BGGNucleonElasticXS::Initialise()
{
  theA[0] = theA[1] = 1;
  G4ThreeVector mom(0.0,0.0,1.0);
  G4DynamicParticle dp(theProton, mom, fGlauberEnergy);
 
  G4NistManager* nist = G4NistManager::Instance();
  G4double csup, csdn;
 
  for (G4int iz=2; iz<93; ++iz) {
    G4int A = G4lrint(nist->GetAtomicMassAmu(iz));
    theA[iz] = A;
 
    csup = fGlauber->GetElasticGlauberGribov(&dp, iz, A);
    csdn = fNucleon->GetElasticCrossSection(&dp, iz);
    theGlauberFacP[iz] = csdn/csup;
  }
 
  dp.SetDefinition(G4Neutron::Neutron());
  for (G4int iz=2; iz<93; ++iz) {
    csup = fGlauber->GetElasticGlauberGribov(&dp, iz, theA[iz]);
    csdn = fNucleon->GetElasticCrossSection(&dp, iz);
    theGlauberFacN[iz] = csdn/csup;
 
    if (verboseLevel > 1) { 
        G4cout << "G4BGGNucleonElasticXS::Initialise Z=" << iz <<  "  A=" << theA[iz] 
               << " GFactorP=" << theGlauberFacP[iz]
               << " GFactorN=" << theGlauberFacN[iz] << G4endl;
    } 
  }
 
  theCoulombFacP[0] = theCoulombFacP[1] = 
    theCoulombFacN[0] = theCoulombFacN[1] = 1.0; 
  dp.SetDefinition(theProton);
  dp.SetKineticEnergy(fLowEnergy);
  for (G4int iz=2; iz<93; ++iz) {
    theCoulombFacP[iz] = fNucleon->GetElasticCrossSection(&dp, iz)
      /CoulombFactor(fLowEnergy, iz);
  }
  dp.SetDefinition(G4Neutron::Neutron());
  for(G4int iz=2; iz<93; ++iz) {
    theCoulombFacN[iz] = fNucleon->GetElasticCrossSection(&dp, iz)
      /CoulombFactor(fLowEnergy, iz);
 
    if (verboseLevel > 1) {
      G4cout << "G4BGGNucleonElasticXS::Initialise Z=" << iz <<  "  A=" << theA[iz]
         << " CFactorP=" << theCoulombFacP[iz] 
         << " CFactorN=" << theCoulombFacN[iz] << G4endl;
    }
  }
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
G4double G4BGGNucleonElasticXS::CoulombFactor(G4double kinEnergy, G4int Z)
{
  return (isProton) ?
    G4NuclearRadii::CoulombFactor(Z, theA[Z], theProton, kinEnergy) : 1.0;  
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......
 
void G4BGGNucleonElasticXS::CrossSectionDescription(std::ostream& outFile) const
{
  outFile << "The Barashenkov-Glauber-Gribov cross section handles elastic\n"
          << "scattering of protons and neutrons from nuclei using the\n"
          << "Barashenkov parameterization below 91 GeV and the Glauber-Gribov\n"
          << "parameterization above 91 GeV. n";
}
 
//....oooOO0OOooo........oooOO0OOooo........oooOO0OOooo........oooOO0OOooo......