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// ---------------------------------------------------------------
//  GEANT 4 class header file
//
//  GVFlashHomoShowerTuning
//
//  Class description:
//
//  Tuning class for GFlash homogeneous shower parameterisation.
//  Definitions:
//    <t>: shower center of gravity
//      T: Depth at shower maximum
//     Ec: Critical energy
//     X0: Radiation length
//     y = E/Ec
//
//  Homogeneous media:
//    Average shower profile
//    (1/E)(dE(t)/dt) = f(t)
//                    = (beta*t)**(alpha-1)*beta*std::exp(-beta*t)/Gamma(alpha)
//    where Gamma is the Gamma function
//
//    <t> = alpha/beta
//      T = (alpha-1)/beta
//    and
//      T = ln(y) + t1
//  alpha = a1+(a2+a3/Z)ln(y)

// Author: J.P. Wellisch - October 2004
//---------------------------------------------------------------
#ifndef GVFlashHomoShowerTuning_hh
#define GVFlashHomoShowerTuning_hh

#include "G4Types.hh"

class GVFlashHomoShowerTuning
{
  public:
    GVFlashHomoShowerTuning() {}
    virtual ~GVFlashHomoShowerTuning() {}
  
  public: // with description

    virtual G4double ParAveT1(){ return -0.812;} // t1
    virtual G4double ParAveA1(){ return 0.81;  } // a1
    virtual G4double ParAveA2(){ return 0.458; } // a2
    virtual G4double ParAveA3(){ return 2.26;  } // a3
  
    virtual G4double ParSigLogT1(){ return -1.4;} // t1
    virtual G4double ParSigLogT2(){ return 1.26;} // t2
      // std::sqrt(var(ln(T))) = 1/(t+t2*ln(y))

    virtual G4double ParSigLogA1(){ return -0.58;} // a1
    virtual G4double ParSigLogA2(){ return 0.86; } // a2
      // std::sqrt(var(ln(alpha))) = 1/(a1+a2*ln(y))
  
    virtual G4double ParRho1(){ return 0.705; } // r1
    virtual G4double ParRho2(){ return -0.023;} // r2
      // Correlation(ln(T),ln(alpha))=r1+r2*ln(y)

    // Radial profiles
    // f(r) := (1/dE(t))(dE(t,r)/dr)
    // Ansatz:
    // f(r) = p(2*r*Rc**2)/(r**2+Rc**2)**2+(1-p)*(2*r*Rt**2)/(r**2+Rt**2)**2,
    //        0<p<1

    virtual G4double ParRC1(){ return 0.0251;   } // c1
    virtual G4double ParRC2(){ return 0.00319;  } // c2
    virtual G4double ParRC3(){ return 0.1162;   } // c3
    virtual G4double ParRC4(){ return -0.000381;} // c4
      // Rc (t/T)= z1 +z2*t/T
      // z1 = c1+c2*ln(E/GeV)
      // z2 = c3+c4*Z
  
    virtual G4double ParRT1(){ return 0.659;   } // t1
    virtual G4double ParRT2(){ return -0.00309;} // t2
    virtual G4double ParRT3(){ return 0.645;   } // k2
    virtual G4double ParRT4(){ return -2.59;   } // k3
    virtual G4double ParRT5(){ return 0.3585;  } // t5
    virtual G4double ParRT6(){ return 0.0412;  } // t6
      // Rt (t/T)= k1*(std::exp(k3*(t/T-k2))+std::exp(k4*(t/T-k2)))
      // k1 = t1+t2*Z
      // k4 = t5+t6*ln(E/GeV)
  
    virtual G4double ParWC1(){ return 2.632;   } // c1
    virtual G4double ParWC2(){ return -0.00094;} // c2
    virtual G4double ParWC3(){ return 0.401;   } // c3
    virtual G4double ParWC4(){ return 0.00187; } // c4
    virtual G4double ParWC5(){ return 1.313;   } // c5
    virtual G4double ParWC6(){ return -0.0686; } // c6
      // p(t/T) = p1*std::exp((p2-t/T)/p3 - std::exp((p2-t/T)/p3))
      // p1 = c1+c2*Z
      // p2 = c3+c4*Z
      // p3 = c5 + c6*ln(E/GeV)

    virtual G4double ParSpotN1(){ return 93.;  } // n1
    virtual G4double ParSpotN2(){ return 0.876;} // n2
      // Fluctuations on radial profiles through number of spots
      // The total number of spots needed for a shower is
      // Ns = n1*ln(Z)(E/GeV)**n2

    // The number of spots per longitudinal interval is:
    // (1/Ns)(dNs(t)/dt) = f(t)
    //  = (beta*t)**(alpha-1)*beta*std::exp(-beta*t)/Gamma(alpha)
    // <t> = alpha_s/beta_s
    // Ts = (alpha_s-1)/beta_s
    // and
    // Ts = T*(t1+t2*Z)
    // alpha_s = alpha*(a1+a2*Z)

    virtual G4double ParSpotT1(){ return 0.698;  } // t1
    virtual G4double ParSpotT2(){ return 0.00212;} // t2
  
    virtual G4double ParSpotA1(){ return 0.639;  } //a1
    virtual G4double ParSpotA2(){ return 0.00334;} //a2

};

#endif
