G4PreCompoundAlpha.cc

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// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4PreCompoundAlpha
//
// Author:         V.Lara
//
// Modified:  
// 21.08.2008 J. M. Quesada add choice of options  
// 20.08.2010 V.Ivanchenko added G4Pow and G4PreCompoundParameters pointers
//                         use int Z and A and cleanup
// 05.07.2013 J.M. Quesada FactorialFactor fixed
//
 
#include "G4PreCompoundAlpha.hh"
#include "G4CoulombBarrier.hh"
#include "G4Alpha.hh"
 
G4PreCompoundAlpha::G4PreCompoundAlpha()
  : G4PreCompoundIon(G4Alpha::Alpha(), new G4CoulombBarrier(4, 2))
{}
 
G4double G4PreCompoundAlpha::FactorialFactor(G4int N, G4int P) const
{
  return static_cast<G4double>(((N-4)*(P-3)*(N-3)*(P-2))*((N-2)*(P-1)*(N-1)*P))
    /144.0;
}
  
G4double G4PreCompoundAlpha::CoalescenceFactor(G4int A) const
{
  return 4096.0/static_cast<G4double>(A*A*A);
}    
 
G4double G4PreCompoundAlpha::GetAlpha() const
{
  G4double C = 0.0;
  if (theFragZ <= 30) 
    {
      C = 0.10;
    } 
  else if (theFragZ <= 50) 
    {
      C = 0.1 - (theFragZ-30)*0.001;
    } 
  else if (theFragZ < 70) 
    {
      C = 0.08 - (theFragZ-50)*0.001;
    }
  else 
    {
      C = 0.06;
    }
  return 1.0+C;
}
 
G4double G4PreCompoundAlpha::GetRj(G4int nParticles, G4int nCharged) const
{
  G4double rj = 0.0;
  if(nCharged >=2 && (nParticles-nCharged) >=2 ) {
    G4double denominator = (G4double)
      (nParticles*(nParticles-1))*((nParticles-2)*(nParticles-3));
    rj = (6.0*nCharged*(nCharged-1))*
      ((nParticles-nCharged)*(nParticles-nCharged-1))/denominator;
  }
  return rj;
}