G4GNASHTransitions.cc

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// $Id: G4GNASHTransitions.cc 69581 2013-05-08 14:02:06Z gcosmo $
//
// 20.08.2010 V.Ivanchenko move constructor and destructor to the source 

#include "G4GNASHTransitions.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"
#include "G4PreCompoundParameters.hh"
#include "G4HadronicException.hh"

G4GNASHTransitions::G4GNASHTransitions()
{
  theParameters = new G4PreCompoundParameters();
}

G4GNASHTransitions::~G4GNASHTransitions()
{
  delete theParameters;
}

G4double G4GNASHTransitions::
CalculateProbability(const G4Fragment & aFragment)
{
  static const G4double k = 135.0 * MeV*MeV*MeV;
  G4double E = aFragment.GetExcitationEnergy();
  G4double P = aFragment.GetNumberOfParticles();
  G4double H = aFragment.GetNumberOfHoles();
  G4double N = P + H;
  G4double A = aFragment.GetA_asInt();

  G4double theMatrixElement(k*N/(A*A*A*E));
  G4double x = E/N;
  if ( x < 2.0*MeV ) theMatrixElement *= x/std::sqrt(14.0*MeV*MeV);
  else if ( x < 7.0*MeV ) x *= std::sqrt(x/7.0*MeV);
  else if ( x < 15.0*MeV ) ;
  else x *= std::sqrt(15.0*MeV/x);

  // gg = (6.0/pi2)*a*A
  G4double gg =  (6.0/pi2)*theParameters->GetLevelDensity()*A;

  G4double Epauli = ((P+1.0)*(P+1.0) + (H+1.0)*(H+1.0) + (P+1.0) - 3.0*(H-1.0))/4.0;

  G4double Probability = gg*gg*gg *(E-Epauli)*(E-Epauli);
  Probability /= 2.0*(N+1.0)*h_Planck;
  Probability *= theMatrixElement;

  return Probability;
}

void G4GNASHTransitions::PerformTransition(G4Fragment & result)
{
  result.SetNumberOfParticles(result.GetNumberOfParticles()+1);
  result.SetNumberOfHoles(result.GetNumberOfHoles()+1);
  if (G4UniformRand()*result.GetA_asInt() <= G4double(result.GetZ_asInt()))
    {
      result.SetNumberOfCharged(result.GetNumberOfCharged()+1);
    }

  if (result.GetNumberOfParticles() < result.GetNumberOfCharged())
    {
      result.SetNumberOfCharged(result.GetNumberOfParticles());
    }
}