/* University College London Dept of Physics Course in C++ 3C59 
| all rights reserved 2000
|
| Utility: The Photomultiplier class
|
|   This class represents a photomultiplier used in the compton scattering
|   experiment. 
|   It contains the concept of a finite front window and detectes
|   whether Particles thrown at it would enter and be detected.
|
|   For such detected particles it simulates the PMT energy resolution of
|   80 kev and adds the detected energy to a running average fo all particles which
|   have entered it so far.
|
| Author: P.Clarke 
*/

#ifndef  _photomultiplier_h
#define  _photomultiplier_h 1

#include "Photon.h"
#include "../util/RanGen.h"


// Define the class

class PhotoMultiplier 
{

  private:

    // Attributes fo detector
    float m_centralAngle ;  // Position of centre in degrees
    float m_lolim ;         // lower angular acceptance
    float m_hilim ;         // higher angular acceptance
    float m_resolution ;    // Energy resolution of this detector in keV

    // Needed to accumulate average energy.
    int   m_numberDetectedParticles ;
    float m_totalEnergy ;

    // Needed to generate gaussian random numbers
    RanGen m_generator ;

    //To assimilate Photon attributes in the case of a detected particle
    void assimilate( Photon& );

  public:

    //Constructor taking:
    //  center = angle setting of centre of detector
    //  dist   = distance of entrance window of PMT from centre of experiment
    //  window = widthe of entrance window
    //  res    = energy resolution of detector
    PhotoMultiplier( float center, float dist, float window, float res ) ;

    // Method to fire a Photon into the detector
    void tryit( Photon& ) ;

    // Method to return number of particles detected so far
    int numberAccepted( ) ;

    // Method to return average energy of detected particles
    float averageEnergy( ) ;  

    // Method to return central angle 
    float angle( ) ;  

};


#endif