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// $Id: G4PreCompoundDeuteron.cc,v 1.6 2010/04/09 14:06:17 vnivanch Exp $
// GEANT4 tag $Name: geant4-09-04-beta-01 $
//
// -------------------------------------------------------------------
//
// GEANT4 Class file
//
//
// File name:     G4PreCompoundDeuteron
//
// Author:         V.Lara
//
// Modified:  
// 21.08.2008 J. M. Quesada add choice of options  
//

#include "G4PreCompoundDeuteron.hh"

G4ReactionProduct * G4PreCompoundDeuteron::GetReactionProduct() const
{
  G4ReactionProduct * theReactionProduct =
    new G4ReactionProduct(G4Deuteron::DeuteronDefinition());
  theReactionProduct->SetMomentum(GetMomentum().vect());
  theReactionProduct->SetTotalEnergy(GetMomentum().e());
#ifdef PRECOMPOUND_TEST
  theReactionProduct->SetCreatorModel("G4PrecompoundModel");
#endif
  return theReactionProduct;
}   

 
G4double G4PreCompoundDeuteron::FactorialFactor(const G4double N, const G4double P)
{
  return (N-1.0)*(N-2.0)*(P-1.0)*P/2.0;
}
  
G4double G4PreCompoundDeuteron::CoalescenceFactor(const G4double A)
{
  return 16.0/A;
}    

G4double G4PreCompoundDeuteron::GetRj(const G4int NumberParticles, const G4int NumberCharged)
{
  G4double rj = 0.0;
  G4double denominator = NumberParticles*(NumberParticles-1);
  if(NumberCharged >=1 && (NumberParticles-NumberCharged) >=1) {
    rj = 2.0*static_cast<G4double>(NumberCharged*(NumberParticles-NumberCharged))
      / static_cast<G4double>(denominator); 
  }
  return rj;
}

////////////////////////////////////////////////////////////////////////////////////
//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 G4PreCompoundDeuteron::CrossSection(const  G4double K)
{

  ResidualA=GetRestA();
  ResidualZ=GetRestZ(); 
  theA=GetA();
  theZ=GetZ();
  ResidualAthrd=std::pow(ResidualA,0.33333);
  FragmentA=GetA()+GetRestA();
  FragmentAthrd=std::pow(FragmentA,0.33333);


  if (OPTxs==0) return GetOpt0( K);
  else if( OPTxs==1 || OPTxs==2) return GetOpt12( K);
  else if (OPTxs==3 || OPTxs==4)  return GetOpt34( K);
  else{
    std::ostringstream errOs;
    errOs << "BAD DEUTERON CROSS SECTION OPTION !!"  <<G4endl;
    throw G4HadronicException(__FILE__, __LINE__, errOs.str());
    return 0.;
  }
}

// *********************** OPT=0 : Dostrovski's cross section  *****************************

G4double G4PreCompoundDeuteron::GetOpt0(const  G4double K)
{
  const G4double r0 = G4PreCompoundParameters::GetAddress()->Getr0();
  // cross section is now given in mb (r0 is in mm) for the sake of consistency
  //with the rest of the options
  return 1.e+25*pi*(r0*ResidualAthrd)*(r0*ResidualAthrd)*GetAlpha()*(1.+GetBeta()/K);
}
//
//---------
//
G4double G4PreCompoundDeuteron::GetAlpha()
{
  G4double C = 0.0;
  G4double aZ = GetZ() + GetRestZ();
  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 1.0 + C/2.0;
}
//
//---------
//
G4double G4PreCompoundDeuteron::GetBeta() 
{
  return -GetCoulombBarrier();
}
//
//********************* OPT=1,2 : Chatterjee's cross section ************************ 
//(fitting to cross section from Bechetti & Greenles OM potential)

G4double G4PreCompoundDeuteron::GetOpt12(const  G4double K)
{

  G4double Kc=K;

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

  G4double landa ,mu ,nu ,p , Ec,q,r,ji,xs;
  //G4double Eo(0),epsilon1(0),epsilon2(0),discri(0);

 
  G4double    p0 = -38.21;
  G4double    p1 = 922.6;
  G4double    p2 = -2804.;
  G4double    landa0 = -0.0323;
  G4double    landa1 = -5.48;
  G4double    mu0 = 336.1;
  G4double    mu1 = 0.48;
  G4double    nu0 = 524.3;
  G4double    nu1 = -371.8;
  G4double    nu2 = -5.924;  
  G4double    delta=1.2;            
 

  Ec = 1.44*theZ*ResidualZ/(1.5*ResidualAthrd+delta);
  p = p0 + p1/Ec + p2/(Ec*Ec);
  landa = landa0*ResidualA + landa1;
  mu = mu0*std::pow(ResidualA,mu1);
  nu = std::pow(ResidualA,mu1)*(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 G4PreCompoundDeuteron::GetOpt34(const  G4double K)
//     ** d from o.m. of perey and perey
{

  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 = 0.798;
  G4double     p1 = 420.3;
  G4double     p2 = -1651.;
  G4double     landa0 = 0.00619;
  G4double     landa1 = -7.54;
  G4double     mu0 = 583.5;
  G4double     mu1 = 0.337;
  G4double     nu0 = 421.8;
  G4double     nu1 = -474.5;
  G4double     nu2 = -3.592;      
 

  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 = std::pow(ResidualA,mu1);
  mu = mu0 * 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 / 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;

}

//   ************************** end of cross sections *******************************