#include <G4NeutronCaptureXS.hh>

Inheritance diagram for G4NeutronCaptureXS:

Public Member Functions
void	BuildPhysicsTable (const G4ParticleDefinition &) final

G4double	ComputeCrossSection (const G4DynamicParticle , const G4Element , const G4Material *mat=nullptr)

void	CrossSectionDescription (std::ostream &) const final

virtual void	DumpPhysicsTable (const G4ParticleDefinition &)

bool	ForAllAtomsAndEnergies () const

	G4NeutronCaptureXS ()

	G4NeutronCaptureXS (const G4NeutronCaptureXS &)=delete

G4double	GetCrossSection (const G4DynamicParticle , const G4Element , const G4Material *mat=nullptr)

G4double	GetElementCrossSection (const G4DynamicParticle , G4int Z, const G4Material ) final

G4double	GetIsoCrossSection (const G4DynamicParticle , G4int Z, G4int A, const G4Isotope iso, const G4Element elm, const G4Material mat) final

G4double	GetMaxKinEnergy () const

G4double	GetMinKinEnergy () const

const G4String &	GetName () const

virtual G4int	GetVerboseLevel () const

G4bool	IsElementApplicable (const G4DynamicParticle , G4int Z, const G4Material ) final

G4bool	IsIsoApplicable (const G4DynamicParticle , G4int Z, G4int A, const G4Element , const G4Material *) final

G4double	IsoCrossSection (G4double ekin, G4double logekin, G4int Z, G4int A)

G4NeutronCaptureXS &	operator= (const G4NeutronCaptureXS &right)=delete

const G4Isotope *	SelectIsotope (const G4Element *, G4double kinEnergy, G4double logE) final

void	SetForAllAtomsAndEnergies (G4bool val)

void	SetMaxKinEnergy (G4double value)

void	SetMinKinEnergy (G4double value)

void	SetName (const G4String &nam)

virtual void	SetVerboseLevel (G4int value)

	~G4NeutronCaptureXS () final

Static Public Member Functions
static const char *	Default_Name ()

Protected Attributes
G4String	name

G4int	verboseLevel

Private Member Functions
const G4String &	FindDirectoryPath ()

const G4PhysicsVector *	GetPhysicsVector (G4int Z)

void	Initialise (G4int Z)

void	InitialiseOnFly (G4int Z)

G4PhysicsVector *	RetrieveVector (std::ostringstream &in, G4bool warn)

Private Attributes
G4double	elimit

G4double	emax

G4bool	isForAllAtomsAndEnergies

G4bool	isMaster = false

G4double	logElimit

G4double	maxKinEnergy

G4double	minKinEnergy

G4CrossSectionDataSetRegistry *	registry

std::vector< G4double >	temp

Static Private Attributes
static G4ElementData *	data = nullptr

static G4String	gDataDirectory = ""

static const G4int	MAXZCAPTURE = 93

Detailed Description

Definition at line 58 of file G4NeutronCaptureXS.hh.

Constructor & Destructor Documentation

◆ G4NeutronCaptureXS() [1/2]

G4NeutronCaptureXS::G4NeutronCaptureXS ( )

explicit

Definition at line 59 of file G4NeutronCaptureXS.cc.

 : G4VCrossSectionDataSet(Default_Name()),
   emax(20*CLHEP::MeV),elimit(1.0e-10*CLHEP::eV)
{
  //  verboseLevel = 0;
  if(verboseLevel > 0){
    G4cout  << "G4NeutronCaptureXS::G4NeutronCaptureXS: Initialise for Z < "
        << MAXZCAPTURE << G4endl;
  }
  logElimit = G4Log(elimit);
}

References elimit, G4cout, G4endl, G4Log(), logElimit, MAXZCAPTURE, and G4VCrossSectionDataSet::verboseLevel.

◆ ~G4NeutronCaptureXS()

G4NeutronCaptureXS::~G4NeutronCaptureXS ( )

final

Definition at line 71 of file G4NeutronCaptureXS.cc.

{
  if(isMaster) { delete data; data = nullptr; }
}

References data, and isMaster.

◆ G4NeutronCaptureXS() [2/2]

G4NeutronCaptureXS::G4NeutronCaptureXS ( const G4NeutronCaptureXS & )

delete

Member Function Documentation

◆ BuildPhysicsTable()

void G4NeutronCaptureXS::BuildPhysicsTable ( const G4ParticleDefinition & p )

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 234 of file G4NeutronCaptureXS.cc.

{
  if(verboseLevel > 0){
    G4cout << "G4NeutronCaptureXS::BuildPhysicsTable for " 
       << p.GetParticleName() << G4endl;
  }
  if(p.GetParticleName() != "neutron") { 
    G4ExceptionDescription ed;
    ed << p.GetParticleName() << " is a wrong particle type -"
       << " only neutron is allowed";
    G4Exception("G4NeutronCaptureXS::BuildPhysicsTable(..)","had012",
        FatalException, ed, "");
    return; 
  }
 
  if(nullptr == data) { 
#ifdef G4MULTITHREADED
    G4MUTEXLOCK(&neutronCaptureXSMutex);
    if(nullptr == data) { 
#endif
      isMaster = true;
      data = new G4ElementData();
      data->SetName("NeutronCapture");
      FindDirectoryPath();
#ifdef G4MULTITHREADED
    }
    G4MUTEXUNLOCK(&neutronCaptureXSMutex);
#endif
  }
 
  // it is possible re-initialisation for the second run
  const G4ElementTable* table = G4Element::GetElementTable();
  if(isMaster) {
 
    // Access to elements
    for ( auto & elm : *table ) {
      G4int Z = std::max( 1, std::min( elm->GetZasInt(), MAXZCAPTURE-1) );
      if ( nullptr == data->GetElementData(Z) ) { Initialise(Z); }
    }
  }
  // prepare isotope selection
  size_t nIso = temp.size();
  for ( auto & elm : *table ) {
    size_t n = elm->GetNumberOfIsotopes();
    if(n > nIso) { nIso = n; }
  }
  temp.resize(nIso, 0.0);
}

References data, FatalException, FindDirectoryPath(), G4cout, G4endl, G4Exception(), G4MUTEXLOCK, G4MUTEXUNLOCK, G4ElementData::GetElementData(), G4Element::GetElementTable(), G4ParticleDefinition::GetParticleName(), Initialise(), isMaster, G4INCL::Math::max(), MAXZCAPTURE, G4INCL::Math::min(), CLHEP::detail::n, G4ElementData::SetName(), temp, G4VCrossSectionDataSet::verboseLevel, and Z.

◆ ComputeCrossSection()

G4double G4VCrossSectionDataSet::ComputeCrossSection	(	const G4DynamicParticle *	part,
		const G4Element *	elm,
		const G4Material *	mat = `nullptr`
	)

inherited

Definition at line 81 of file G4VCrossSectionDataSet.cc.

{
  G4int Z = elm->GetZasInt();
 
  if (IsElementApplicable(part, Z, mat)) { 
    return GetElementCrossSection(part, Z, mat);
  }
 
  // isotope-wise cross section making sum over available
  // isotope cross sections, which may be incomplete, so
  // the result is corrected 
  size_t nIso = elm->GetNumberOfIsotopes();    
  G4double fact = 0.0;
  G4double xsec = 0.0;
 
  // user-defined isotope abundances        
  const G4IsotopeVector* isoVector = elm->GetIsotopeVector();
  const G4double* abundVector = elm->GetRelativeAbundanceVector();
 
  for (size_t j=0; j<nIso; ++j) {
    const G4Isotope* iso = (*isoVector)[j];
    G4int A = iso->GetN();
    if(abundVector[j] > 0.0 && IsIsoApplicable(part, Z, A, elm, mat)) {
      fact += abundVector[j];
      xsec += abundVector[j]*GetIsoCrossSection(part, Z, A, iso, elm, mat);
    }
  }
  return (fact > 0.0) ? xsec/fact : 0.0; 
}

References A, G4VCrossSectionDataSet::GetElementCrossSection(), G4VCrossSectionDataSet::GetIsoCrossSection(), G4Element::GetIsotopeVector(), G4Isotope::GetN(), G4Element::GetNumberOfIsotopes(), G4Element::GetRelativeAbundanceVector(), G4Element::GetZasInt(), G4VCrossSectionDataSet::IsElementApplicable(), G4VCrossSectionDataSet::IsIsoApplicable(), and Z.

Referenced by G4VCrossSectionDataSet::GetCrossSection().

◆ CrossSectionDescription()

void G4NeutronCaptureXS::CrossSectionDescription ( std::ostream & outFile ) const

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 76 of file G4NeutronCaptureXS.cc.

{
  outFile << "G4NeutronCaptureXS calculates the neutron capture cross sections\n"
          << "on nuclei using data from the high precision neutron database.\n"
          << "These data are simplified and smoothed over the resonance region\n"
          << "in order to reduce CPU time.  G4NeutronCaptureXS is set to zero\n"
          << "above 20 MeV for all targets. Cross section is zero also for Z>92.\n";
}

◆ Default_Name()

static const char * G4NeutronCaptureXS::Default_Name ( )

inlinestatic

Definition at line 66 of file G4NeutronCaptureXS.hh.

66{return "G4NeutronCaptureXS";}

Referenced by LBE::ConstructHad(), and G4NeutronCrossSectionXS::ConstructProcess().

◆ DumpPhysicsTable()

void G4VCrossSectionDataSet::DumpPhysicsTable ( const G4ParticleDefinition & )

virtualinherited

Reimplemented in G4CrossSectionElastic, G4CrossSectionInelastic, G4LENDCrossSection, G4ParticleHPCaptureData, G4ParticleHPElasticData, G4ParticleHPFissionData, G4ParticleHPInelasticData, G4ParticleHPJENDLHEData, G4ParticleHPThermalScatteringData, and G4UPiNuclearCrossSection.

Definition at line 174 of file G4VCrossSectionDataSet.cc.

175{}

◆ FindDirectoryPath()

const G4String & G4NeutronCaptureXS::FindDirectoryPath ( )

private

Definition at line 283 of file G4NeutronCaptureXS.cc.

{
  // check environment variable
  // build the complete string identifying the file with the data set
  if(gDataDirectory.empty()) {
    char* path = std::getenv("G4PARTICLEXSDATA");
    if (nullptr != path) {
      std::ostringstream ost;
      ost << path << "/neutron/cap";
      gDataDirectory = ost.str();
    } else {
      G4Exception("G4NeutronCaptureXS::Initialise(..)","had013",
          FatalException,
          "Environment variable G4PARTICLEXSDATA is not defined");
    }
  }
  return gDataDirectory;
}

References FatalException, G4Exception(), and gDataDirectory.

Referenced by BuildPhysicsTable(), and Initialise().

◆ ForAllAtomsAndEnergies()

bool G4VCrossSectionDataSet::ForAllAtomsAndEnergies ( ) const

inlineinherited

Definition at line 230 of file G4VCrossSectionDataSet.hh.

{
  return isForAllAtomsAndEnergies;
}

References G4VCrossSectionDataSet::isForAllAtomsAndEnergies.

Referenced by G4CrossSectionDataStore::AddDataSet().

◆ GetCrossSection()

G4double G4VCrossSectionDataSet::GetCrossSection	(	const G4DynamicParticle *	dp,
		const G4Element *	elm,
		const G4Material *	mat = `nullptr`
	)

inlineinherited

Definition at line 187 of file G4VCrossSectionDataSet.hh.

{
  return ComputeCrossSection(dp, elm, mat);
}

References G4VCrossSectionDataSet::ComputeCrossSection().

◆ GetElementCrossSection()

G4double G4NeutronCaptureXS::GetElementCrossSection	(	const G4DynamicParticle *	aParticle,
		G4int	Z,
		const G4Material *
	)

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 101 of file G4NeutronCaptureXS.cc.

{
  G4double xs = 0.0;
  G4double ekin = aParticle->GetKineticEnergy();
  if(ekin > emax) { return xs; }
 
  G4int Z = std::min(ZZ, MAXZCAPTURE-1);
  G4double logEkin = aParticle->GetLogKineticEnergy();
  if(ekin < elimit) { ekin = elimit; logEkin = logElimit; }
 
  auto pv = GetPhysicsVector(Z);
  if(pv == nullptr) { return xs; }
 
  const G4double e1 = pv->Energy(1);
  xs = (ekin >= e1) ? pv->LogVectorValue(ekin, logEkin) 
    : (*pv)[1]*std::sqrt(e1/ekin); 
 
#ifdef G4VERBOSE
  if(verboseLevel > 1){
    G4cout  << "Ekin= " << ekin/CLHEP::MeV 
            << " ElmXScap(b)= " << xs/CLHEP::barn << G4endl;
  }
#endif
  return xs;
}

References CLHEP::barn, e1, elimit, emax, G4cout, G4endl, G4DynamicParticle::GetKineticEnergy(), G4DynamicParticle::GetLogKineticEnergy(), GetPhysicsVector(), logElimit, MAXZCAPTURE, CLHEP::MeV, G4INCL::Math::min(), G4VCrossSectionDataSet::verboseLevel, and Z.

◆ GetIsoCrossSection()

G4double G4NeutronCaptureXS::GetIsoCrossSection	(	const G4DynamicParticle *	aParticle,
		G4int	Z,
		G4int	A,
		const G4Isotope *	iso,
		const G4Element *	elm,
		const G4Material *	mat
	)

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 129 of file G4NeutronCaptureXS.cc.

{
  return IsoCrossSection(aParticle->GetKineticEnergy(), 
                         aParticle->GetLogKineticEnergy(),
                         Z, A); 
}

References A, G4DynamicParticle::GetKineticEnergy(), G4DynamicParticle::GetLogKineticEnergy(), IsoCrossSection(), and Z.

◆ GetMaxKinEnergy()

G4double G4VCrossSectionDataSet::GetMaxKinEnergy ( ) const

inlineinherited

Definition at line 220 of file G4VCrossSectionDataSet.hh.

{
  return maxKinEnergy;
}

References G4VCrossSectionDataSet::maxKinEnergy.

Referenced by G4CrossSectionElastic::IsElementApplicable(), G4CrossSectionInelastic::IsElementApplicable(), G4LENDCrossSection::IsIsoApplicable(), G4ParticleHPCaptureData::IsIsoApplicable(), G4ParticleHPElasticData::IsIsoApplicable(), G4ParticleHPFissionData::IsIsoApplicable(), and G4ParticleHPInelasticData::IsIsoApplicable().

◆ GetMinKinEnergy()

G4double G4VCrossSectionDataSet::GetMinKinEnergy ( ) const

inlineinherited

Definition at line 210 of file G4VCrossSectionDataSet.hh.

{
  return minKinEnergy;
}

References G4VCrossSectionDataSet::minKinEnergy.

Referenced by G4CrossSectionElastic::IsElementApplicable(), G4CrossSectionInelastic::IsElementApplicable(), G4LENDCrossSection::IsIsoApplicable(), G4ParticleHPCaptureData::IsIsoApplicable(), G4ParticleHPElasticData::IsIsoApplicable(), G4ParticleHPFissionData::IsIsoApplicable(), and G4ParticleHPInelasticData::IsIsoApplicable().

◆ GetName()

const G4String & G4VCrossSectionDataSet::GetName ( ) const

inlineinherited

Definition at line 225 of file G4VCrossSectionDataSet.hh.

{
  return name;
}

References G4VCrossSectionDataSet::name.

Referenced by G4LENDCrossSection::DumpLENDTargetInfo(), G4LENDCrossSection::DumpPhysicsTable(), G4LENDCrossSection::GetIsoCrossSection(), and G4CrossSectionDataStore::PrintCrossSectionHtml().

◆ GetPhysicsVector()

const G4PhysicsVector * G4NeutronCaptureXS::GetPhysicsVector ( G4int Z )

inlineprivate

Definition at line 124 of file G4NeutronCaptureXS.hh.

{
  const G4PhysicsVector* pv = data->GetElementData(Z);
  if(pv == nullptr) { 
    InitialiseOnFly(Z);
    pv = data->GetElementData(Z);
  }
  return pv;
}

References data, G4ElementData::GetElementData(), InitialiseOnFly(), and Z.

Referenced by GetElementCrossSection(), and IsoCrossSection().

◆ GetVerboseLevel()

G4int G4VCrossSectionDataSet::GetVerboseLevel ( ) const

inlinevirtualinherited

Reimplemented in G4ParticleHPCaptureData, G4ParticleHPElasticData, G4ParticleHPFissionData, and G4ParticleHPInelasticData.

Definition at line 195 of file G4VCrossSectionDataSet.hh.

{
  return verboseLevel;
}

References G4VCrossSectionDataSet::verboseLevel.

◆ Initialise()

void G4NeutronCaptureXS::Initialise ( G4int Z )

private

Definition at line 315 of file G4NeutronCaptureXS.cc.

{
  if(nullptr != data->GetElementData(Z)) { return; }
 
  // upload element data 
  std::ostringstream ost;
  ost << FindDirectoryPath() << Z ;
  G4PhysicsVector* v = RetrieveVector(ost, true);
  data->InitialiseForElement(Z, v);
 
  // upload isotope data
  if(amin[Z] < amax[Z]) {
    G4int nmax = amax[Z] - amin[Z] + 1;
    data->InitialiseForComponent(Z, nmax);
 
    for(G4int A=amin[Z]; A<=amax[Z]; ++A) {
      std::ostringstream ost1;
      ost1 << gDataDirectory << Z << "_" << A;
      v = RetrieveVector(ost1, false);
      data->AddComponent(Z, A, v); 
    }
  }
}

References A, G4ElementData::AddComponent(), amax, amin, data, FindDirectoryPath(), gDataDirectory, G4ElementData::GetElementData(), G4ElementData::InitialiseForComponent(), G4ElementData::InitialiseForElement(), RetrieveVector(), and Z.

Referenced by BuildPhysicsTable(), and InitialiseOnFly().

◆ InitialiseOnFly()

void G4NeutronCaptureXS::InitialiseOnFly ( G4int Z )

private

Definition at line 302 of file G4NeutronCaptureXS.cc.

{
#ifdef G4MULTITHREADED
   G4MUTEXLOCK(&neutronCaptureXSMutex);
   if(nullptr == data->GetElementData(Z)) { 
#endif
     Initialise(Z);
#ifdef G4MULTITHREADED
   }
   G4MUTEXUNLOCK(&neutronCaptureXSMutex);
#endif
}

References data, G4MUTEXLOCK, G4MUTEXUNLOCK, G4ElementData::GetElementData(), Initialise(), and Z.

Referenced by GetPhysicsVector().

◆ IsElementApplicable()

G4bool G4NeutronCaptureXS::IsElementApplicable	(	const G4DynamicParticle *	,
		G4int	Z,
		const G4Material *
	)

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 86 of file G4NeutronCaptureXS.cc.

{
  return true;
}

◆ IsIsoApplicable()

G4bool G4NeutronCaptureXS::IsIsoApplicable	(	const G4DynamicParticle *	,
		G4int	Z,
		G4int	A,
		const G4Element *	,
		const G4Material *
	)

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 93 of file G4NeutronCaptureXS.cc.

{
  return true;
}

◆ IsoCrossSection()

G4double G4NeutronCaptureXS::IsoCrossSection	(	G4double	ekin,
		G4double	logekin,
		G4int	Z,
		G4int	A
	)

Definition at line 139 of file G4NeutronCaptureXS.cc.

{
  G4double xs = 0.0;
  if(eKin > emax) { return xs; }
 
  G4int Z = std::min(ZZ, MAXZCAPTURE-1);
  G4double ekin = eKin;
  G4double logEkin = logE;
  if(ekin < elimit) { 
    ekin = elimit; 
    logEkin = logElimit; 
  }
 
  auto pv = GetPhysicsVector(Z);
  if(pv == nullptr) { return xs; }
 
  if(amin[Z] < amax[Z] && A >= amin[Z] && A <= amax[Z]) {
    G4PhysicsVector* pviso = data->GetComponentDataByIndex(Z, A - amin[Z]);
    if(pviso != nullptr) { 
      const G4double e1 = pviso->Energy(1);
      xs = (ekin >= e1) ? pviso->LogVectorValue(ekin, logEkin)
    : (*pviso)[1]*std::sqrt(e1/ekin); 
#ifdef G4VERBOSE
      if(verboseLevel > 0) {
    G4cout << "G4NeutronCaptureXS::IsoXS: Ekin(MeV)= " << ekin/MeV 
           << "  xs(b)= " << xs/barn 
           << "  Z= " << Z << "  A= " << A << G4endl;
      }
#endif
      return xs;
    }
  }
  // isotope data are not available or applicable
  const G4double e1 = pv->Energy(1);
  xs = (ekin >= e1) ? pv->LogVectorValue(ekin, logEkin)
    : (*pv)[1]*std::sqrt(e1/ekin); 
#ifdef G4VERBOSE
  if(verboseLevel > 0) {
    G4cout << "G4NeutronCaptureXS::IsoXS: Ekin(MeV)= " << ekin/MeV 
           << "  xs(b)= " << xs/barn 
       << "  Z= " << Z << "  A= " << A << " no iso XS" << G4endl;
  }
#endif
  return xs;
}

References A, amax, amin, barn, data, e1, elimit, emax, G4PhysicsVector::Energy(), G4cout, G4endl, G4ElementData::GetComponentDataByIndex(), GetPhysicsVector(), logElimit, G4PhysicsVector::LogVectorValue(), MAXZCAPTURE, MeV, G4INCL::Math::min(), G4VCrossSectionDataSet::verboseLevel, and Z.

Referenced by GetIsoCrossSection(), and SelectIsotope().

◆ operator=()

G4NeutronCaptureXS & G4NeutronCaptureXS::operator= ( const G4NeutronCaptureXS & right )

delete

◆ RetrieveVector()

G4PhysicsVector * G4NeutronCaptureXS::RetrieveVector	(	std::ostringstream &	in,
		G4bool	warn
	)

private

Definition at line 340 of file G4NeutronCaptureXS.cc.

{
  G4PhysicsLogVector* v = nullptr;
  std::ifstream filein(ost.str().c_str());
  if (!filein.is_open()) {
    if(warn) {
      G4ExceptionDescription ed;
      ed << "Data file <" << ost.str().c_str()
     << "> is not opened!";
      G4Exception("G4NeutronCaptureXS::RetrieveVector(..)","had014",
          FatalException, ed, "Check G4PARTICLEXSDATA");
    }
  } else {
    if(verboseLevel > 1) {
      G4cout << "File " << ost.str() 
         << " is opened by G4NeutronCaptureXS" << G4endl;
    }
    // retrieve data from DB
    v = new G4PhysicsLogVector();
    if(!v->Retrieve(filein, true)) {
      G4ExceptionDescription ed;
      ed << "Data file <" << ost.str().c_str()
     << "> is not retrieved!";
      G4Exception("G4NeutronCaptureXS::RetrieveVector(..)","had015",
          FatalException, ed, "Check G4PARTICLEXSDATA");
    }
  }
  return v;
}

References FatalException, G4cout, G4endl, G4Exception(), G4PhysicsVector::Retrieve(), and G4VCrossSectionDataSet::verboseLevel.

Referenced by Initialise().

◆ SelectIsotope()

const G4Isotope * G4NeutronCaptureXS::SelectIsotope	(	const G4Element *	anElement,
		G4double	kinEnergy,
		G4double	logE
	)

finalvirtual

Reimplemented from G4VCrossSectionDataSet.

Definition at line 187 of file G4NeutronCaptureXS.cc.

{
  size_t nIso = anElement->GetNumberOfIsotopes();
  const G4Isotope* iso = anElement->GetIsotope(0);
 
  //G4cout << "SelectIsotope NIso= " << nIso << G4endl;
  if(1 == nIso) { return iso; }
 
  // more than 1 isotope
  G4int Z = anElement->GetZasInt();
 
  const G4double* abundVector = anElement->GetRelativeAbundanceVector();
  G4double q = G4UniformRand();
  G4double sum = 0.0;
 
  // is there isotope wise cross section?
  size_t j;
  if(amax[Z] == amin[Z] || Z >= MAXZCAPTURE) {
    for (j = 0; j<nIso; ++j) {
      sum += abundVector[j];
      if(q <= sum) {
    iso = anElement->GetIsotope(j);
    break;
      }
    }
    return iso;
  } 
  size_t nn = temp.size();
  if(nn < nIso) { temp.resize(nIso, 0.); }
 
  for (j=0; j<nIso; ++j) {
    sum += abundVector[j]*IsoCrossSection(kinEnergy, logE, Z, 
                      anElement->GetIsotope(j)->GetN());
    temp[j] = sum;
  }
  sum *= q;
  for (j = 0; j<nIso; ++j) {
    if(temp[j] >= sum) {
      iso = anElement->GetIsotope(j);
      break;
    }
  }
  return iso;
}