#ifndef ALITRDSIM_H
#define ALITRDSIM_H
/* Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
 * See cxx source for full Copyright notice                               */

/* $Id$ */

///////////////////////////////////////////////////////////////////////////////
//                                                                           //
//  TRD simulation - multimodule (regular rad.)                              //
//                                                                           //
///////////////////////////////////////////////////////////////////////////////

#include <TObject.h>

class TH1D;

class AliModule;

class AliTRDsim : public TObject {

 public:

  AliTRDsim();
  AliTRDsim(const AliTRDsim &s);
  AliTRDsim(AliModule *mod, Int_t foil, Int_t gap);
  virtual ~AliTRDsim();
  AliTRDsim &operator=(const AliTRDsim &s);

  virtual void          Copy(TObject &s);
  virtual void          Init();
  virtual Int_t         CreatePhotons(Int_t pdg, Float_t p
                                    , Int_t &nPhoton, Float_t *ePhoton);
  virtual Int_t         TrPhotons(Double_t gamma, Int_t &nPhoton, Float_t *ePhoton);
  virtual Double_t      Sigma(Double_t energykeV);
  virtual Double_t      Interpolate(Double_t energyMeV
                                  , Double_t *en, Double_t *mu, Int_t n);
  virtual Int_t         Locate(Double_t *xv, Int_t n, Double_t xval
                             , Int_t &kl, Double_t &dx);
  virtual Double_t      Omega(Float_t rho, Float_t z, Float_t a) 
                             { return (28.8 * TMath::Sqrt(rho * z / a)); };

          void          SetNFoils(Int_t n)      { fNFoils    = n;       };
          void          SetFoilThick(Float_t t) { fFoilThick = t;
                           SetSigma();                                  };
          void          SetGapThick(Float_t t)  { fGapThick  = t;
                           SetSigma();                                  };
          void          SetFoilDens(Float_t d)  { fFoilDens  = d; 
                           fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
                           SetSigma();                                  };
          void          SetFoilZ(Float_t z)     { fFoilZ     = z; 
                           fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA); };
          void          SetFoilA(Float_t a)     { fFoilA     = a; 
                           fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA); };
          void          SetGapDens(Float_t d)   { fGapDens   = d;
                           fGapOmega  = Omega(fGapDens ,fGapZ ,fGapA );
                           SetSigma();                                  };
          void          SetGapZ(Float_t z)      { fGapZ      = z;
                           fGapOmega  = Omega(fGapDens ,fGapZ ,fGapA ); };
          void          SetGapA(Float_t a)      { fGapA      = a;
                           fGapOmega  = Omega(fGapDens ,fGapZ ,fGapA ); };
          void          SetTemp(Float_t t)      { fTemp      = t; 
                           SetSigma();                                  };
          void          SetSigma();

  virtual Double_t      GetMuPo(Double_t energyMeV);
  virtual Double_t      GetMuCO(Double_t energyMeV);
  virtual Double_t      GetMuXe(Double_t energyMeV);
  virtual Double_t      GetMuBu(Double_t energyMeV);
  virtual Double_t      GetMuMy(Double_t energyMeV);
  virtual Double_t      GetMuN2(Double_t energyMeV);
  virtual Double_t      GetMuO2(Double_t energyMeV);
  virtual Double_t      GetMuHe(Double_t energyMeV);

          Int_t         GetNFoils() const       { return fNFoils;    };
          Float_t       GetFoilThick() const    { return fFoilThick; };
          Float_t       GetGapThick() const     { return fGapThick;  };
          Float_t       GetFoilDens() const     { return fFoilDens;  };
          Float_t       GetGapDens() const      { return fGapDens;   };
          Double_t      GetFoilOmega() const    { return fFoilOmega; };
          Double_t      GetGapOmega() const     { return fGapOmega;  };
          Float_t       GetTemp() const         { return fTemp;      };
          TH1D         *GetSpectrum() const     { return fSpectrum;  };

 protected:

  Int_t     fNFoils;               // Number of foils in the radiator stack
  Float_t   fFoilThick;            // Thickness of the foils (cm)
  Float_t   fGapThick;             // Thickness of the gaps between the foils (cm)

  Float_t   fFoilDens;             // Density of the radiator foils (g/cm^3) 
  Float_t   fGapDens;              // Density of the gas in the radiator gaps (g/cm^3)

  Double_t  fFoilOmega;            // Plasma frequency of the radiator foils
  Double_t  fGapOmega;             // Plasma frequency of the gas in the radiator gaps

  Float_t   fFoilZ;                // Z of the foil material
  Float_t   fGapZ;                 // Z of the gas in the gaps

  Float_t   fFoilA;                // A of the foil material
  Float_t   fGapA;                 // A of the gas in the gaps

  Float_t   fTemp;                 // Temperature of the radiator gas (Kelvin)

  Int_t     fSpNBins;              // Number of bins of the TR spectrum
  Float_t   fSpRange;              // Range of the TR spectrum
  Float_t   fSpBinWidth;           // Bin width of the TR spectrum
  Float_t   fSpLower;              // Lower border of the TR spectrum
  Float_t   fSpUpper;              // Upper border of the TR spectrum

  Double_t *fSigma;                //[fSpNBins] Array of sigma values

  TH1D     *fSpectrum;             //!TR photon energy spectrum

  ClassDef(AliTRDsim,1)            // Simulates TR photons

};
#endif