// This code implementation is the intellectual property of
// the GEANT4 collaboration.
//
// By copying, distributing or modifying the Program (or any work
// based on the Program) you indicate your acceptance of this statement,
// and all its terms.
//
// $Id: G4MuPairProduction.icc,v 1.3 2000/02/10 08:29:13 urban Exp $
// GEANT4 tag $Name: geant4-02-00 $
//
// ---------------------------------------------------------------
//      GEANT 4 class inlined methods file 
//
//      For information related to this code contact:
//      CERN, CN Division, ASD group
//      History: first implementation, based on object model of
//      2nd December 1995, G.Cosmo
//      -------- G4MuPairProduction physics process ---------
//                by Laszlo Urban, May 1998  
// ***************************************************************

inline G4double G4MuPairProduction::GetMeanFreePath(const G4Track& trackData,
                                                    G4double previousStepSize,
                                                    G4ForceCondition* condition)
{
   const G4DynamicParticle* aDynamicParticle;
   G4Material* aMaterial;
   G4double MeanFreePath;
   G4bool isOutRange ;
 
   *condition = NotForced ;

   aDynamicParticle = trackData.GetDynamicParticle();
   aMaterial = trackData.GetMaterial();
   G4double KineticEnergy = aDynamicParticle->GetKineticEnergy();

   if (KineticEnergy <  LowestKineticEnergy)
     MeanFreePath = DBL_MAX ;
   else {
     if (KineticEnergy > HighestKineticEnergy) 
                             KineticEnergy = 0.99*HighestKineticEnergy ;
     MeanFreePath = (*theMeanFreePathTable)(aMaterial->GetIndex())->
                    GetValue( KineticEnergy, isOutRange );
   }
   return MeanFreePath; 
} 

inline G4double G4MuPairProduction::ComputeMeanFreePath(
                                     const G4ParticleDefinition* ParticleType,
                                     G4double KineticEnergy,
                                     const G4Material* aMaterial)
{
  const G4ElementVector* theElementVector = aMaterial->GetElementVector() ;
  const G4double* theAtomNumDensityVector = 
                                      aMaterial->GetAtomicNumDensityVector();
  G4double ElectronEnergyCut =
                       (G4Electron::GetCutsInEnergy())[aMaterial->GetIndex()];  
  G4double PositronEnergyCut =
                       (G4Positron::GetCutsInEnergy())[aMaterial->GetIndex()];  

  G4double SIGMA = 0 ;
  for ( G4int i=0 ; i < aMaterial->GetNumberOfElements() ; i++ )
      {             
            SIGMA += theAtomNumDensityVector[i] * 
                  ComputeMicroscopicCrossSection( ParticleType, KineticEnergy,
                                         (*theElementVector)(i)->GetZ(), 
                                         ElectronEnergyCut,PositronEnergyCut );
      }       

  return SIGMA<=0.0 ? DBL_MAX : 1./SIGMA ;
}

inline G4bool G4MuPairProduction::IsApplicable(
                            const G4ParticleDefinition& particle)
{
   return(   (&particle == (const G4ParticleDefinition *)theMuonMinus)
           ||(&particle == (const G4ParticleDefinition *)theMuonPlus)
         ) ;
}
