G4HETCAlpha.cc

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//
// $Id$
//
// by V. Lara
//
// Modified:
// 23.08.2010 V.Ivanchenko general cleanup, move constructor and destructor 
//            the source, use G4Pow

#include "G4HETCAlpha.hh"
#include "G4Alpha.hh"

G4HETCAlpha::G4HETCAlpha() 
  : G4HETCChargedFragment(G4Alpha::Alpha(), &theAlphaCoulombBarrier)
{}

G4HETCAlpha::~G4HETCAlpha() 
{}

G4double G4HETCAlpha::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;
}
  
G4double G4HETCAlpha::GetBeta()
{
  return -GetCoulombBarrier();
}
  
G4double G4HETCAlpha::GetSpinFactor()
{
  return 1.0;
}

G4double G4HETCAlpha::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 > 3)
    {
      result = 3.0/(P*(P-1.0)*(P-2.0)*(P-3.0)) * 
    (H*(H-1.0)*(H-2.0)*(H-3.0)*r*r*(r-1.0)*(r-1.0) +
     2.0*H*(H-1.0)*(H-2.0)*(Pa*r*(1.0-r)*(1.0-r)+Na*r*r*(1.0-r)) +
     H*(H-1.0)*(Pa*(Pa-1.0)*(1.0-r)*(1.0-r)+4.0*Na*Pa*r*(1.0-r)+Na*(Na-1.0)*r*r) +
     2*H*(Pa*Na*(Na-1.0)*r+Pa*(Pa-1.0)*Na*(1.0-r)) +
     Pa*(Pa-1.0)*Na*(Na-1.0));

      result /= 6.0*r*r*(1. - r) *(1. - r);
    }
  return std::max(0.0,result);
}