G4ElementSelector.cc

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//
// $Id$
//
// File: G4ElementSelector
//
// Author:        V.Ivanchenko (Vladimir.Ivanchenko@cern.ch)
// 
// Creation date: 2 April 2000
//
// Modifications: 
// 18/08/2000  V.Ivanchenko Update description
// 17/05/2006  V.Ivanchenko Cleanup
// 02/10/2007  V.Ivanchenko Fixed typo in computation of Lambda-factor
//                          proposed by Victor Pec 
//
//---------------------------------------------------------------------

#include "G4ElementSelector.hh"
#include "Randomize.hh" 
#include "G4Material.hh"
#include "G4Nucleus.hh"

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G4ElementSelector::G4ElementSelector()
{}

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G4ElementSelector::~G4ElementSelector()
{}

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G4Element* 
G4ElementSelector::SelectZandA(const G4Track& track, G4Nucleus* target)
{
  // Fermi-Teller Z-low of mu- capture and exceptions 
  // for halogens and oxigen.
  // N.C.Mukhopadhyay Phys. Rep. 30 (1977) 1.

  size_t i = 0;
  const G4Material* mat = track.GetMaterial();
  size_t numberOfElements = mat->GetNumberOfElements();
  const G4ElementVector* theElementVector = mat->GetElementVector();

  if(1 < numberOfElements) {
    if(numberOfElements > prob.size()) { prob.resize(numberOfElements, 0.0); }
    
    const G4double* theAtomNumDensity = mat->GetAtomicNumDensityVector();

    G4double sum = 0.0;
    for (i=0; i < numberOfElements; ++i) {

      G4int Z = G4lrint((*theElementVector)[i]->GetZ()); 

      // Halogens
      if( (9 == Z) || (17 == Z) || (35 == Z) || (53 == Z) || (85 == Z) ) {
        sum += 0.66 * Z * theAtomNumDensity[i]; 

        // Oxigen
      } else if( 8 == Z ) {
        sum += 0.56 * Z * theAtomNumDensity[i]; 

        // Others
      } else {
        sum += Z * theAtomNumDensity[i]; 
      }
      prob[i] = sum;
    }
 
    sum *= G4UniformRand();
    for (i=0; i < numberOfElements; ++i) {
      if(sum <= prob[i]) { break; }
    }
  }
  
  G4Element* elm = (*theElementVector)[i];
  G4int Z = G4lrint(elm->GetZ());

  // select isotope
  const G4IsotopeVector* isv = elm->GetIsotopeVector();
  size_t ni = isv->size();
  i = 0;

  if(1 < ni) {

    const G4double* ab = elm->GetRelativeAbundanceVector();
    G4double y = G4UniformRand();
    for(i=0; i<ni; ++i) {
      y -= ab[i];
      if(y <= 0.0) { break; }
    }
  }

  G4int A = elm->GetIsotope(i)->GetN();
  target->SetParameters(A, Z);

  return elm;
}

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