JNPEHit.hh

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#ifndef __JFIT__JNPEHIT__
#define __JFIT__JNPEHIT__
 
#include "JFit/JNPE.hh"
 
 
/**
 * \author mdejong
 */
 
namespace JFIT {}
namespace JPP { using namespace JFIT; }
 
namespace JFIT {
  
  /**
   * Auxiliary class for simultaneously handling light yields and response of PMT.
   */
  struct JNPEHit :
    public JNPE
  {
    /**
     * Default constructor.
     */
    JNPEHit() :
      JNPE(),
      ns  (0),
      ps  (1.0)
    {}
 
 
    /**
     * Constructor.
     *
     * \param  npe                npe
     * \param  ns                 number of hits
     * \param  ps                 survival probability of one photo-electron
     */
    JNPEHit(const JNPE&  npe,
            const size_t ns,
            const double ps) :
      JNPE(npe),
      ns  (ns),
      ps  (ps)
    {}
        
 
    /**
     * Get number of hits.
     *
     * \return                    number of hits
     */
    inline size_t getN() const
    {
      return ns;
    }
 
 
    /**
     * Get survival probability of one photo-electron.
     *
     * \return                    survival probability of one photo-electron
     */
    double getPS() const
    {
      return ps;
    }
 
 
    /**
     * Get muon energy dependent probability.
     *
     * \param  E_GeV              energy [GeV]
     * \return                    probability
     */
    double getP(const double E_GeV) const
    {
      const double x  = this->getH1(E_GeV) + this->getH0();  // expectation value for total number of photo-electrons
 
      const double p0 = exp(-x) * (1.0 +                     // Poisson probability of 0 photo-electrons  OR
                                   x * (1.0 - ps));          // Poisson probability of 1 photo-electron   AND  NOT survive
 
      if (this->getN() > 0)
        return 1.0 - p0;
      else
        return p0;
    }
 
 
    /**
     * Get chi2.
     *
     * \param  E_GeV              energy [GeV]
     * \return                    chi2
     */
    double getChi2(const double E_GeV) const
    {
      return -log(this->getP(E_GeV));
    }
 
  protected:
    size_t ns;      //!< number of hits
    double ps;      //!< survival probability of one photo-electron
  };
}
 
#endif