source: trunk/source/processes/hadronic/models/de_excitation/evaporation/src/G4EvaporationProbability.cc @ 1007

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//J.M. Quesada (August2008). Based on:
//
// Hadronic Process: Nuclear De-excitations
// by V. Lara (Oct 1998)
//
// Modif (03 September 2008) by J. M. Quesada for external choice of inverse 
// cross section option
// JMQ (06 September 2008) Also external choices have been added for 
// superimposed Coulomb barrier (if useSICB is set true, by default is false) 

#include <iostream>
using namespace std;

#include "G4EvaporationProbability.hh"
#include "G4PairingCorrection.hh"



G4EvaporationProbability::G4EvaporationProbability(const G4EvaporationProbability &) : G4VEmissionProbability()
{
    throw G4HadronicException(__FILE__, __LINE__, "G4EvaporationProbability::copy_constructor meant to not be accessable");
}




const G4EvaporationProbability & G4EvaporationProbability::
operator=(const G4EvaporationProbability &)
{
    throw G4HadronicException(__FILE__, __LINE__, "G4EvaporationProbability::operator= meant to not be accessable");
    return *this;
}


G4bool G4EvaporationProbability::operator==(const G4EvaporationProbability &) const
{
    return false;
}

G4bool G4EvaporationProbability::operator!=(const G4EvaporationProbability &) const
{
    return true;
}
  
G4double G4EvaporationProbability::EmissionProbability(const G4Fragment & fragment, const G4double anEnergy)
{
    G4double EmissionProbability = 0.0;
    G4double MaximalKineticEnergy = anEnergy;

    if (MaximalKineticEnergy > 0.0 && fragment.GetExcitationEnergy() > 0.0) {
        EmissionProbability = CalculateProbability(fragment, MaximalKineticEnergy);

    }
    return EmissionProbability;
}

////////////////////////////////////

// Computes the integrated probability of evaporation channel
G4double G4EvaporationProbability::CalculateProbability(const G4Fragment & fragment, const G4double MaximalKineticEnergy)
{
    G4double ResidualA = fragment.GetA() - theA;
    G4double ResidualZ = fragment.GetZ() - theZ;
    G4double U = fragment.GetExcitationEnergy();
   
 if (OPTxs==0) {

        
    G4double NuclearMass = G4ParticleTable::GetParticleTable()->GetIonTable()->GetNucleusMass(theZ,theA);


    G4double delta0 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(fragment.GetA()),
                                                                               static_cast<G4int>(fragment.GetZ()));

    G4double SystemEntropy = 2.0*std::sqrt(theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(fragment.GetA()),
                                                                           static_cast<G4int>(fragment.GetZ()),U)*
                                      (U-delta0));
                                                                  

    G4double RN = 1.5*fermi;

    G4double Alpha = CalcAlphaParam(fragment);
    G4double Beta = CalcBetaParam(fragment);
        
    G4double Rmax = MaximalKineticEnergy;
    G4double a = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(ResidualA),
                                                      static_cast<G4int>(ResidualZ),
                                                      Rmax);
    G4double GlobalFactor = static_cast<G4double>(Gamma) * (Alpha/(a*a)) *
        (NuclearMass*RN*RN*std::pow(ResidualA,2./3.))/
        (2.*pi* hbar_Planck*hbar_Planck);
    G4double Term1 = (2.0*Beta*a-3.0)/2.0 + Rmax*a;
    G4double Term2 = (2.0*Beta*a-3.0)*std::sqrt(Rmax*a) + 2.0*a*Rmax;
        
    G4double ExpTerm1 = 0.0;
    if (SystemEntropy <= 600.0) ExpTerm1 = std::exp(-SystemEntropy);
        
    G4double ExpTerm2 = 2.*std::sqrt(a*Rmax) - SystemEntropy;
    if (ExpTerm2 > 700.0) ExpTerm2 = 700.0;
    ExpTerm2 = std::exp(ExpTerm2);
        
    G4double Width = GlobalFactor*(Term1*ExpTerm1 + Term2*ExpTerm2);
        
    return Width;
             
 } else if (OPTxs==1 || OPTxs==2 ||OPTxs==3 || OPTxs==4) {

   G4double limit;
   if (useSICB) limit=theCoulombBarrierptr->GetCoulombBarrier(G4lrint(ResidualA),G4lrint(ResidualZ),U);
   else limit=0.;

   if (MaximalKineticEnergy <= limit)  return 0.0;


// if Coulomb barrier cutoff is superimposed for all cross sections the limit is the Coulomb Barrier
        G4double LowerLimit= limit;

//  MaximalKineticEnergy: asimptotic value (already accounted for in G4EvaporationChannel)     

  G4double UpperLimit = MaximalKineticEnergy;


  G4double Width = IntegrateEmissionProbability(fragment,LowerLimit,UpperLimit);

  return Width;
 } else{
   std::ostringstream errOs;
   errOs << "Bad option for cross sections at evaporation"  <<G4endl;
   throw G4HadronicException(__FILE__, __LINE__, errOs.str());
 }
  
}

/////////////////////////////////////////////////////////////////////

G4double G4EvaporationProbability::
IntegrateEmissionProbability(const G4Fragment & fragment, const G4double & Low, const G4double & Up )
{

  static const G4int N = 10;
  // 10-Points Gauss-Legendre abcisas and weights
  static const G4double w[N] = {
    0.0666713443086881,
    0.149451349150581,
    0.219086362515982,
    0.269266719309996,
    0.295524224714753,
    0.295524224714753,
    0.269266719309996,
    0.219086362515982,
    0.149451349150581,
    0.0666713443086881
  };
  static const G4double x[N] = {
    -0.973906528517172,
    -0.865063366688985,
    -0.679409568299024,
    -0.433395394129247,
    -0.148874338981631,
    0.148874338981631,
    0.433395394129247,
    0.679409568299024,
    0.865063366688985,
    0.973906528517172
  };

  G4double Total = 0.0;


  for (G4int i = 0; i < N; i++) 
    {

      G4double KineticE = ((Up-Low)*x[i]+(Up+Low))/2.0;

      Total += w[i]*ProbabilityDistributionFunction(fragment, KineticE);

    }
  Total *= (Up-Low)/2.0;
  return Total;
}


/////////////////////////////////////////////////////////
//New method (OPT=1,2,3,4)

G4double G4EvaporationProbability::ProbabilityDistributionFunction( const G4Fragment & fragment, const G4double K)
{ 

 


  G4double ResidualA = fragment.GetA() - theA;
  G4double ResidualZ = fragment.GetZ() - theZ;  
  G4double U = fragment.GetExcitationEnergy();

  //        if(K <= theCoulombBarrierptr->GetCoulombBarrier(G4lrint(ResidualA),G4lrint(ResidualZ),U)) return 0.0;   

  G4double delta1 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(ResidualA),static_cast<G4int>(ResidualZ));

 
  G4double delta0 = G4PairingCorrection::GetInstance()->GetPairingCorrection(static_cast<G4int>(fragment.GetA()),static_cast<G4int>(fragment.GetZ()));

  
  G4double ParticleMass = G4ParticleTable::GetParticleTable()->GetIonTable()->GetNucleusMass(theZ,theA);

  G4double theSeparationEnergy= G4NucleiProperties::GetMassExcess(static_cast<G4int>(theA),static_cast<G4int>(theZ)) +
    G4NucleiProperties::GetMassExcess(static_cast<G4int>(ResidualA),static_cast<G4int>(ResidualZ)) -
    G4NucleiProperties::GetMassExcess(static_cast<G4int>(fragment.GetA()),static_cast<G4int>(fragment.GetZ()));

  G4double a0 = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(fragment.GetA()),static_cast<G4int>(fragment.GetZ()),U - delta0);

  G4double a1 = theEvapLDPptr->LevelDensityParameter(static_cast<G4int>(ResidualA),static_cast<G4int>(ResidualZ),U - theSeparationEnergy - delta1);
  
  
  G4double E0=U-delta0;

  G4double E1=U-theSeparationEnergy-delta1-K;

  if (E1<0.) return 0.;


//Without 1/hbar_Panck remains as a width

  G4double  Prob=Gamma*ParticleMass/((pi*hbar_Planck)*(pi*hbar_Planck)*std::exp(2*std::sqrt(a0*E0)))*K*CrossSection(fragment,K)*std::exp(2*std::sqrt(a1*E1))*millibarn;

return Prob;

}