G4PreCompoundNucleon.cc

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// $Id: G4PreCompoundNucleon.cc 91837 2015-08-07 07:27:08Z gcosmo $
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4PreCompoundNucleon
//
// Author:         V.Lara
//
// Modified:  
// 10.02.2009 J. M. Quesada cleanup
// 20.08.2010 V.Ivanchenko added G4Pow and G4PreCompoundParameters pointers
//                         use int Z and A and cleanup
//

#include "G4PreCompoundNucleon.hh"
#include "G4PhysicalConstants.hh"
#include "G4SystemOfUnits.hh"

const G4double sixoverpi2 = 6.0/CLHEP::pi2;
const G4double fact = 2*CLHEP::millibarn/(CLHEP::pi2*CLHEP::hbarc*CLHEP::hbarc*CLHEP::hbarc);

G4PreCompoundNucleon::
G4PreCompoundNucleon(const G4ParticleDefinition* part,
                     G4VCoulombBarrier* aCoulombBarrier)
  : G4PreCompoundFragment(part,aCoulombBarrier)
{}

G4PreCompoundNucleon::~G4PreCompoundNucleon()
{}

G4double G4PreCompoundNucleon::
ProbabilityDistributionFunction(G4double eKin, 
                                const G4Fragment& aFragment)
{
  G4double U = aFragment.GetExcitationEnergy();
  G4int P = aFragment.GetNumberOfParticles();
  G4int H = aFragment.GetNumberOfHoles();
  G4int N = P + H;

  G4double g0 = sixoverpi2*theFragA*theParameters->GetLevelDensity();
  G4double g1 = sixoverpi2*theResA*theParameters->GetLevelDensity();
  
  G4double A0 = G4double(P*P+H*H+P-3*H)/(4.0*g0);
  G4double A1 = (A0 - 0.5*P)/g1;  

  G4double E0 = U - A0;
  if (E0 <= 0.0) { return 0.0; }

  G4double E1 = U - eKin -  theBindingEnergy - A1;
  if (E1 <= 0.0) { return 0.0; }

  G4double rj = GetRj(P, aFragment.GetNumberOfCharged());
  G4double xs = CrossSection(eKin);

  if (rj <0.0 || xs < 0.0) {  
    std::ostringstream errOs;
    errOs << "Rj=" << rj <<"  xsec("
          <<eKin/MeV<<" MeV)= "<< xs <<"  A= "<<GetA()<<"  Z= "<<GetZ()
          <<G4endl;
    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
  }

  G4double Probability = fact * theReducedMass * rj * xs * eKin * P * (N-1) 
    * g4pow->powN(g1*E1/(g0*E0),N-2) * g1 / (E0*g0*g0);
  
  return Probability;
}