G4TritonEvaporationProbability.cc

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// $Id$
//
// J.M. Quesada (August2008). Based on:
//
// Hadronic Process: Nuclear De-excitations
// by V. Lara (Oct 1998)
//
// Modified:
// 03-09-2008 J.M. Quesada for external choice of inverse cross section option
// 17-11-2010 V.Ivanchenko integer Z and A

#include "G4TritonEvaporationProbability.hh"
#include "G4SystemOfUnits.hh"

G4TritonEvaporationProbability::G4TritonEvaporationProbability() :
    G4EvaporationProbability(3,1,2,&theCoulombBarrier) // A,Z,Gamma,&theCoulombBarrier
{
  ResidualA = ResidualZ = theA = theZ = FragmentA = 0;
  ResidualAthrd = FragmentAthrd = 0.0;
}

G4TritonEvaporationProbability::~G4TritonEvaporationProbability()
{}

G4double G4TritonEvaporationProbability::CalcAlphaParam(const G4Fragment & fragment) 
{ 
  return 1.0 + CCoeficient(fragment.GetZ_asInt()-GetZ());
}
        
G4double G4TritonEvaporationProbability::CalcBetaParam(const G4Fragment & ) 
{ 
  return 0.0; 
}

G4double G4TritonEvaporationProbability::CCoeficient(G4int aZ) 
{
  // Data comes from 
  // Dostrovsky, Fraenkel and Friedlander
  // Physical Review, vol 116, num. 3 1959
  // 
  // const G4int size = 5;
  // G4double Zlist[5] = { 10.0, 20.0, 30.0, 50.0, 70.0};
  // G4double Cp[5] = { 0.50, 0.28, 0.20, 0.15, 0.10};
  // C for triton is equal to C for protons divided by 3
  G4double C = 0.0;
        
  if (aZ >= 70) {
    C = 0.10;
  } else {
    C = ((((0.15417e-06*aZ) - 0.29875e-04)*aZ + 0.21071e-02)*aZ - 0.66612e-01)*aZ + 0.98375;
  }
        
  return C/3.0;
}

//J. M. Quesada (Dec 2007-June 2008): New inverse reaction cross sections 
//OPT=0 Dostrovski's parameterization
//OPT=1,2 Chatterjee's paramaterization 
//OPT=3,4 Kalbach's parameterization 
// 
G4double 
G4TritonEvaporationProbability::CrossSection(const  G4Fragment & fragment, G4double K)
{
  theA=GetA();
  theZ=GetZ();
  ResidualA=fragment.GetA_asInt()-theA;
  ResidualZ=fragment.GetZ_asInt()-theZ; 
  
  ResidualAthrd=fG4pow->Z13(ResidualA);
  FragmentA=fragment.GetA_asInt();
  FragmentAthrd=fG4pow->Z13(FragmentA);

  if (OPTxs==0) {std::ostringstream errOs;
    errOs << "We should'n be here (OPT =0) at evaporation cross section calculation (tritons)!!"  
          <<G4endl;
    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
    return 0.;}
  if( OPTxs==1 || OPTxs==2) return G4TritonEvaporationProbability::GetOpt12( K);
  else if (OPTxs==3 || OPTxs==4)  return G4TritonEvaporationProbability::GetOpt34( K);
  else{
    std::ostringstream errOs;
    errOs << "BAD Triton CROSS SECTION OPTION AT EVAPORATION!!"  <<G4endl;
    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
    return 0.;
  }
}

//
//********************* OPT=1,2 : Chatterjee's cross section *****************
//(fitting to cross section from Bechetti & Greenles OM potential)

G4double G4TritonEvaporationProbability::GetOpt12(G4double K)
{
  G4double Kc=K;

  // JMQ xsec is set constat above limit of validity
  if (K > 50*MeV) { Kc=50*MeV; }

  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
 
  G4double    p0 = -11.04;
  G4double    p1 = 619.1;
  G4double    p2 = -2147.;
  G4double    landa0 = -0.0426;
  G4double    landa1 = -10.33;
  G4double    mum0 = 601.9;
  G4double    mu1 = 0.37;
  G4double    nu0 = 583.0;
  G4double    nu1 = -546.2;
  G4double    nu2 = 1.718;  
  G4double    delta=1.2;            

  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
  p = p0 + p1/Ec + p2/(Ec*Ec);
  landa = landa0*ResidualA + landa1;

  G4double resmu1 = fG4pow->powZ(ResidualA,mu1); 
  mu = mum0*resmu1;
  nu = resmu1*(nu0 + nu1*Ec + nu2*(Ec*Ec));
  q = landa - nu/(Ec*Ec) - 2*p*Ec;
  r = mu + 2*nu/Ec + p*(Ec*Ec);
  
  ji=std::max(Kc,Ec);
  if(Kc < Ec) { xs = p*Kc*Kc + q*Kc + r;}
  else {xs = p*(Kc - ji)*(Kc - ji) + landa*Kc + mu + nu*(2 - Kc/ji)/ji ;}
                 
  if (xs <0.0) {xs=0.0;}
              
  return xs;
}

// *********** OPT=3,4 : Kalbach's cross sections (from PRECO code)*************
G4double G4TritonEvaporationProbability::GetOpt34(G4double K)
//     ** t from o.m. of hafele, flynn et al
{
  G4double landa, mu, nu, p , signor(1.),sig;
  G4double ec,ecsq,xnulam,etest(0.),a; 
  G4double b,ecut,cut,ecut2,geom,elab;

  G4double     flow = 1.e-18;
  G4double     spill= 1.e+18;

  G4double     p0 = -21.45;
  G4double     p1 = 484.7;
  G4double     p2 = -1608.;
  G4double     landa0 = 0.0186;
  G4double     landa1 = -8.90;
  G4double     mum0 = 686.3;
  G4double     mu1 = 0.325;
  G4double     nu0 = 368.9;
  G4double     nu1 = -522.2;
  G4double     nu2 = -4.998;  
  
  G4double      ra=0.80;
        
  //JMQ 13/02/09 increase of reduced radius to lower the barrier
  // ec = 1.44 * theZ * ResidualZ / (1.5*ResidualAthrd+ra);
  ec = 1.44 * theZ * ResidualZ / (1.7*ResidualAthrd+ra);
  ecsq = ec * ec;
  p = p0 + p1/ec + p2/ecsq;
  landa = landa0*ResidualA + landa1;
  a = fG4pow->powZ(ResidualA,mu1);
  mu = mum0 * a;
  nu = a* (nu0+nu1*ec+nu2*ecsq);  
  xnulam = nu / landa;
  if (xnulam > spill) { xnulam=0.; }
  if (xnulam >= flow) { etest = 1.2 *std::sqrt(xnulam); }
 
  a = -2.*p*ec + landa - nu/ecsq;
  b = p*ecsq + mu + 2.*nu/ec;
  ecut = 0.;
  cut = a*a - 4.*p*b;
  if (cut > 0.) { ecut = std::sqrt(cut); }
  ecut = (ecut-a) / (p+p);
  ecut2 = ecut;
  //JMQ 290310 for avoiding unphysical increase below minimum (at ecut)
  // ecut<0 means that there is no cut with energy axis, i.e. xs is set 
  // to 0 bellow minimum
  //  if (cut < 0.) ecut2 = ecut - 2.;
  if (cut < 0.) { ecut2 = ecut; }
  elab = K * FragmentA / G4double(ResidualA);
  sig = 0.;
 
  if (elab <= ec) { //start for E<Ec
    if (elab > ecut2) { sig = (p*elab*elab+a*elab+b) * signor; }
  }           //end for E<Ec
  else {           //start for E>Ec
    sig = (landa*elab+mu+nu/elab) * signor;
    geom = 0.;
    if (xnulam < flow || elab < etest) { return sig; }
    geom = std::sqrt(theA*K);
    geom = 1.23*ResidualAthrd + ra + 4.573/geom;
    geom = 31.416 * geom * geom;
    sig = std::max(geom,sig);
  }           //end for E>Ec
  return sig;
}

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