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// $Id: G4HETCHe3.cc,v 1.4 2010/08/28 15:16:55 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-03-ref-09 $
//
// by V. Lara
//
// Modified:
// 23.08.2010 V.Ivanchenko general cleanup, move constructor and destructor 
//            the source, use G4Pow

#include "G4HETCHe3.hh"
#include "G4He3.hh"

G4HETCHe3::G4HETCHe3() 
  : G4HETCChargedFragment(G4He3::He3(), &theHe3CoulombBarrier)
{}

G4HETCHe3::~G4HETCHe3() 
{}

G4double G4HETCHe3::GetAlpha()
{
  G4double C = 0.0;
  G4int aZ = GetZ() + GetRestZ();
  if (aZ <= 30) 
    {
      C = 0.10;
    } 
  else if (aZ <= 50) 
    {
      C = 0.1 + -((aZ-50.)/20.)*0.02;
    } 
  else if (aZ < 70) 
    {
      C = 0.08 + -((aZ-70.)/20.)*0.02;
    }
  else 
    {
      C = 0.06;
    }
  return 1.0 + C*(4.0/3.0);
}
  
G4double G4HETCHe3::GetBeta()
{
  return -GetCoulombBarrier();
}

G4double G4HETCHe3::GetSpinFactor()
{
  // 2s+1
  return 2.0;
}    

G4double G4HETCHe3::K(const G4Fragment & aFragment)
{
  // Number of protons in emitted fragment
  G4int Pa = GetZ();
  // Number of neutrons in emitted fragment 
  G4int Na = GetA() - Pa;

  G4int TargetZ = GetRestZ();
  G4int TargetA = GetRestA();
  G4double r = G4double(TargetZ)/G4double(TargetA);

  G4int P = aFragment.GetNumberOfParticles();
  G4int H = aFragment.GetNumberOfHoles();

  G4double result = 0.0;
  if (P > 2)
    {
      result = 3.0/(P*(P-1.0)*(P-2.0)) * 
	(H*(H-1.0)*(H-2.0)*r*r*(r-1.0) +
	 H*(H-1.0)*(2.0*Na*r*(1.0-r)+Pa*r*r) +
	 H*(Pa*(Pa-1.0)*(r-1.0)+2.0*Na*Pa*r) +
	 Pa*Na*(Pa-1.0));

      result /= 3.0*r*r*(1.0 - r);
    }
  return std::max(0.0,result);
}
