//
// ********************************************************************
// * License and Disclaimer                                           *
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// * technical work of the GEANT4 collaboration.                      *
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// ********************************************************************
// ********************************************************************
// *********************************************************************
// |                                                                   |
// |             G4LowEPComptonModel-- Geant4 Monash University        |
// |                   low energy Compton scattering model.            |
// |             J. M. C. Brown, Monash University, Australia          |
// |                    ## Unpolarised photons only ##                 |
// |                                                                   |
// |                                                                   |
// *********************************************************************
// |                                                                   |
// | The following is a Geant4 class to simulate the process of        |
// | bound electron Compton scattering. General code structure is      |
// | based on G4LowEnergyCompton.cc and G4LivermoreComptonModel.cc.    |
// | Algorithms for photon energy, and ejected Compton electron        |
// | direction taken from:                                             |
// |                                                                   |
// | J. M. C. Brown, M. R. Dimmock, J. E. Gillam and D. M. Paganin,    |
// | "A low energy bound atomic electron Compton scattering model      |
// |  for Geant4", NIMB, Vol. 338, 77-88, 2014.                        |
// |                                                                   |
// | The author acknowledges the work of the Geant4 collaboration      |
// | in developing the following algorithms that have been employed    |
// | or adapeted for the present software:                             |    
// |                                                                   |
// |  # sampling of photon scattering angle,                           |
// |  # target element selection in composite materials,               |
// |  # target shell selection in element,                             |
// |  # and sampling of bound electron momentum from Compton profiles. |
// |                                                                   |
// *********************************************************************
// |                                                                   |
// | History:                                                          |
// | --------                                                          |
// |                                                                   |
// | Nov. 2011 JMCB       - First version                              |
// | Feb. 2012 JMCB       - Migration to Geant4 9.5                    |
// | Sep. 2012 JMCB       - Final fixes for Geant4 9.6                 |
// | Feb. 2013 JMCB       - Geant4 9.6 FPE fix for bug 1426            |
// | Jan. 2015 JMCB       - Migration to MT (Based on Livermore        |
// |                        implementation)                            |
// | Feb. 2016 JMCB       - Geant4 10.2 FPE fix for bug 1676           |
// |                                                                   |
// *********************************************************************

#ifndef G4LowEPComptonModel_h
#define G4LowEPComptonModel_h 1

#include "G4VEmModel.hh"
#include "G4LPhysicsFreeVector.hh"

class G4ParticleChangeForGamma;
class G4VAtomDeexcitation;
class G4ShellData;
class G4DopplerProfile;

class G4LowEPComptonModel : public G4VEmModel
{

public:

  G4LowEPComptonModel(const G4ParticleDefinition* p = 0, 
		          const G4String& nam = "LowEPComptonModel");
  
  virtual ~G4LowEPComptonModel();

  virtual void Initialise(const G4ParticleDefinition*, const G4DataVector&);

  virtual void InitialiseLocal(const G4ParticleDefinition*,
                               G4VEmModel* masterModel);

  virtual void InitialiseForElement(const G4ParticleDefinition*, G4int Z);

  virtual G4double ComputeCrossSectionPerAtom( const G4ParticleDefinition*,
                                               G4double kinEnergy,
                                               G4double Z,
                                               G4double A=0,
                                               G4double cut=0,
                                               G4double emax=DBL_MAX );

  virtual void SampleSecondaries(std::vector<G4DynamicParticle*>*,
                                 const G4MaterialCutsCouple*,
                                 const G4DynamicParticle*,
                                 G4double tmin,
                                 G4double maxEnergy);

private:

  void ReadData(size_t Z, const char* path = 0);

  G4double ComputeScatteringFunction(G4double x, G4int Z);

  G4LowEPComptonModel & operator=(const  G4LowEPComptonModel &right);
  G4LowEPComptonModel(const  G4LowEPComptonModel&);

  G4bool isInitialised;
  G4int verboseLevel;
 
  //G4double lowestEnergy;
 
  G4ParticleChangeForGamma* fParticleChange;
  G4VAtomDeexcitation*      fAtomDeexcitation;

  static G4ShellData*       shellData;
  static G4DopplerProfile*  profileData;

  static G4int maxZ;
  static G4LPhysicsFreeVector* data[100];

  static const G4double ScatFuncFitParam[101][9];
  
};

//****************************************************************************

#endif
