G4NeutronInelasticXS.cc

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// $Id$
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:    G4NeutronInelasticXS
//
// Author  Ivantchenko, Geant4, 3-Aug-09
//
// Modifications:
//

#include "G4HadronicException.hh"
#include "G4NeutronInelasticXS.hh"
#include "G4Neutron.hh"
#include "G4DynamicParticle.hh"
#include "G4Element.hh"
#include "G4ElementTable.hh"
#include "G4PhysicsLogVector.hh"
#include "G4PhysicsVector.hh"
#include "G4GlauberGribovCrossSection.hh"
#include "G4HadronNucleonXsc.hh"
#include "G4NistManager.hh"
#include "G4Proton.hh"
#include "Randomize.hh"

#include <iostream>
#include <fstream>
#include <sstream>

using namespace std;

G4NeutronInelasticXS::G4NeutronInelasticXS() 
  : G4VCrossSectionDataSet("G4NeutronInelasticXS"),
    proton(G4Proton::Proton()), maxZ(92)
{
  //  verboseLevel = 0;
  if(verboseLevel > 0){
    G4cout  << "G4NeutronInelasticXS::G4NeutronInelasticXS Initialise for Z < " 
            << maxZ + 1 << G4endl;
  }
  data.resize(maxZ+1, 0);
  coeff.resize(maxZ+1, 1.0);
  ggXsection = new G4GlauberGribovCrossSection();
  fNucleon = new G4HadronNucleonXsc();
  isInitialized = false;
}

G4NeutronInelasticXS::~G4NeutronInelasticXS()
{
  delete fNucleon;
  for(G4int i=0; i<=maxZ; ++i) {
    delete data[i];
  }
}

void G4NeutronInelasticXS::CrossSectionDescription(std::ostream& outFile) const
{
  outFile << "G4NeutronInelasticXS calculates the neutron inelastic scattering\n"
          << "cross section on nuclei using data from the high precision\n"
          << "neutron database.  These data are simplified and smoothed over\n"
          << "the resonance region in order to reduce CPU time.\n"
          << "G4NeutronInelasticXS is valid for energies up to 20 MeV, for\n"
          << "nuclei through U.\n";
}

G4bool 
G4NeutronInelasticXS::IsElementApplicable(const G4DynamicParticle*, 
                                          G4int, const G4Material*)
{
  return true;
}

G4bool 
G4NeutronInelasticXS::IsIsoApplicable(const G4DynamicParticle*,
                                      G4int /*ZZ*/, G4int /*AA*/,
                                      const G4Element*, const G4Material*)
{
  return false;
}

G4double 
G4NeutronInelasticXS::GetElementCrossSection(const G4DynamicParticle* aParticle,
                                             G4int Z, const G4Material*)
{
  G4double xs = 0.0;
  G4double ekin = aParticle->GetKineticEnergy();

  if(Z < 1 || Z > maxZ) { return xs; }
  G4int Amean = G4int(G4NistManager::Instance()->GetAtomicMassAmu(Z)+0.5);
  G4PhysicsVector* pv = data[Z];
  //  G4cout  << "G4NeutronInelasticXS::GetCrossSection e= " << ekin << " Z= " << Z << G4endl;

  // element was not initialised
  if(!pv) {
    Initialise(Z);
    pv = data[Z];
    if(!pv) { return xs; }
  }

  G4double e1 = pv->Energy(0);
  if(ekin <= e1) { return xs; }

  G4int n = pv->GetVectorLength() - 1;
  G4double e2 = pv->Energy(n);
  if(ekin <= e2) { 
    xs = pv->Value(ekin); 
  } else if(1 == Z) { 
    fNucleon->GetHadronNucleonXscPDG(aParticle, proton);
    xs = coeff[1]*fNucleon->GetInelasticHadronNucleonXsc();
  } else {          
    ggXsection->GetIsoCrossSection(aParticle, Z, Amean);
    xs = coeff[Z]*ggXsection->GetInelasticGlauberGribovXsc();
  }

  if(verboseLevel > 0) {
    G4cout  << "ekin= " << ekin << ",  XSinel= " << xs << G4endl;
  }
  return xs;
}

/*
G4double 
G4NeutronInelasticXS::GetIsoCrossSection(const G4DynamicParticle* aParticle, 
                                         G4int Z, G4int A,
                                         const G4Isotope*, const G4Element*,
                                         const G4Material*)
{
  G4double xs = 0.0;
  G4double ekin = aParticle->GetKineticEnergy();
  if(ekin > emax || Z < 1 || Z > maxZ) { return xs; }
  const G4double elimit = 1.0e-10*eV;
  if(ekin < elimit) { ekin = elimit; }

  //  G4PhysicsVector* pv = data[Z];
  G4PhysicsVector* pv = data.GetElementData(Z);

  // element was not initialised
  if(!pv) {
    Initialise(Z);
    //    pv = data[Z];
    pv = data.GetElementData(Z);
    if(!pv) { return xs; }
  }
  pv = data.GetComponentDataByID(Z, A);
  if(!pv) { return xs; }

  xs = pv->Value(ekin); 

  if(verboseLevel > 0){
    G4cout  << "ekin= " << ekin << ",  xs= " << xs << G4endl;
  }
  return xs;
}

G4Isotope* G4NeutronInelasticXS::SelectIsotope(const G4Element* anElement,
                                               G4double kinEnergy)
{
  G4int nIso = anElement->GetNumberOfIsotopes();
  G4IsotopeVector* isoVector = anElement->GetIsotopeVector();
  G4Isotope* iso = (*isoVector)[0];

  // more than 1 isotope
  if(1 < nIso) {
    G4int Z = G4lrint(anElement->GetZ());
    if(Z > maxZ) { Z = maxZ; }
    G4double* abundVector = anElement->GetRelativeAbundanceVector();
    G4double q = G4UniformRand();
    G4double sum = 0.0;

    // is there isotope wise cross section?
    if(0 == amin[Z]) {
      for (G4int j = 0; j<nIso; ++j) {
        sum += abundVector[j];
        if(q <= sum) {
          iso = (*isoVector)[j];
          break;
        }
      }
    } else {
      size_t nmax = data.GetNumberOfComponents(Z);
      if(temp.size() < nmax) { temp.resize(nmax,0.0); }
      for (size_t i=0; i<nmax; ++i) {
        G4int A = (*isoVector)[i]->GetN();
        G4PhysicsVector* v = data.GetComponentDataByID(Z, A);
        if(v) { sum += abundVector[i]*v->Value(kinEnergy); }
        temp[i] = sum;
      }
      sum *= q;
      for (size_t j = 0; j<nmax; ++j) {
        if(temp[j] >= sum) {
          iso = (*isoVector)[j];
          break;
        }
      }
    }
  }
  return iso;
}
*/
void 
G4NeutronInelasticXS::BuildPhysicsTable(const G4ParticleDefinition& p)
{
  if(isInitialized) { return; }
  if(verboseLevel > 0){
    G4cout << "G4NeutronCaptureXS::BuildPhysicsTable for " 
           << p.GetParticleName() << G4endl;
  }
  if(p.GetParticleName() != "neutron") { 
    throw G4HadronicException(__FILE__, __LINE__,"Wrong particle type");
    return; 
  }
  isInitialized = true;

  // check environment variable 
  // Build the complete string identifying the file with the data set
  char* path = getenv("G4NEUTRONXSDATA");
  if (!path){
    throw G4HadronicException(__FILE__, __LINE__, 
                              "G4NEUTRONXSDATA environment variable not defined");
    return;
  }

  G4DynamicParticle* dynParticle = 
    new G4DynamicParticle(G4Neutron::Neutron(),G4ThreeVector(1,0,0),1);

  // Access to elements
  const G4ElementTable* theElmTable = G4Element::GetElementTable();
  size_t numOfElm = G4Element::GetNumberOfElements();
  if(numOfElm > 0) {
    for(size_t i=0; i<numOfElm; ++i) {
      G4int Z = G4int(((*theElmTable)[i])->GetZ());
      if(Z < 1)         { Z = 1; }
      else if(Z > maxZ) { Z = maxZ; }
      //G4cout << "Z= " << Z << G4endl;
      // Initialisation 
      if(!data[Z]) { Initialise(Z, dynParticle, path); }
    }
  }
  delete dynParticle;
}

void 
G4NeutronInelasticXS::Initialise(G4int Z, G4DynamicParticle* dp, 
                                 const char* p)
{
  if(data[Z]) { return; }
  const char* path = p;
  if(!p) {
  // check environment variable 
  // Build the complete string identifying the file with the data set
    path = getenv("G4NEUTRONXSDATA");
    if (!path) {
      throw G4HadronicException(__FILE__, __LINE__, 
                                "G4NEUTRONXSDATA environment variable not defined");
      return;
    }
  }
  G4DynamicParticle* dynParticle = dp;
  if(!dp) {
    dynParticle = 
      new G4DynamicParticle(G4Neutron::Neutron(),G4ThreeVector(1,0,0),1);
  }

  G4int Amean = G4int(G4NistManager::Instance()->GetAtomicMassAmu(Z)+0.5);

  // upload data from file
  data[Z] = new G4PhysicsLogVector();

  std::ostringstream ost;
  ost << path << "/inelast" << Z ;
  std::ifstream filein(ost.str().c_str());

  if (!(filein)) {
    throw G4HadronicException(__FILE__, __LINE__,"NO data sets opened");
    return;
  }else{
    if(verboseLevel > 1) {
      G4cout << "file " << ost.str() 
             << " is opened by G4NeutronInelasticXS" << G4endl;
    }
    
    // retrieve data from DB
    data[Z]->Retrieve(filein, true);
    
    // smooth transition 
    size_t n      = data[Z]->GetVectorLength() - 1;
    G4double emax = data[Z]->Energy(n);
    G4double sig1 = (*data[Z])[n];
    dynParticle->SetKineticEnergy(emax);
    G4double sig2 = 0.0;
    if(1 == Z) {
      fNucleon->GetHadronNucleonXscPDG(dynParticle, proton);
      sig2 = fNucleon->GetInelasticHadronNucleonXsc();
    } else {
      ggXsection->GetIsoCrossSection(dynParticle, Z, Amean);
      sig2 = ggXsection->GetInelasticGlauberGribovXsc();
    }
    if(sig2 > 0.) { coeff[Z] = sig1/sig2; }
  } 
  if(!dp) { delete dynParticle; }
}

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