PacEmc status              -- Chih-hsiang Cheng 2008/07/24

o  Current version is committed:  revision 270

o  PacEmcModel
     - Reads the config file to set up Emc geometry.

       PacCylDetector {
      		   ... ...
		   ... ...
                   emcBarrelBegin = 0.4695
               	   emcBarrelEnd   = 2.4574
               	   emcBarrelNRings = 48
                   emcBarrelNPhis  = 120
		   ... ...
       }

       PacConeDetector {

                    emcFECBegin =  0.2757
    		    emcFECEnd =    0.4690
                    emcFECNRings = 8
                    emcFECNPhis  = 80, 80, 100, 100, 100, 120, 120, 120
       }


       ** PacConeDetector is not defined yet. This config file uses it
          to set up forward endcap indexing.

       Barrel radius is determined from "radii" and "measures", i.e., the 
       radius of measures = Emc.

       Geometry of Forward Endcap to be defined when PacConeDetector is 
       defined.

     - Phi segmentation is uniform in both barrel and FEC.
     - Theta segmentation is uniform in FEC.
     - Theta segmemtation is not uniform in barrel because the distance
       varies a lot.
         - The segmentation in "pseudo-rapidity", eta, is roughly uniform.
             eta = -ln [ tan(theta/2) ]

     - Translation between crystal index and real (theat,phi) is done 
       in PacEmcModel.

     - Use the static function     PacEmcModel::getModel() to get the model.


o  PacEmcDigi and PacEmcCluster

     - To take the role of EmcDigi and EmcCluster in Babar
         (simplified, without calibration, data-flow info, etc)

     - Often-used moment calculations are imported too, and can be
       accessed to through PacEmcCluster.

     - PacEmcDigi uses PacEmcModel to translate index to real coordinates.


o  PacReconstructEmc

   -  Contains a method returning a PacEmcCluster
    PacEmcCluster *PacReconstructEmc::makeEmcCluster(const PacSimTrack *simtrk)

      if simtrk intersects a detector element with 

          measurementType()==PacMeasurement::Calor

      a cluster is created

          pelem->measurement()->createEmcCluster(*ihit,cluster);
                 -------------
                  |-> a  PacMeasurement


o  PacEmcClusterMeas

     - subclass of PacMeasurement

     - has a method to create a cluster
  virtual void createEmcCluster(const PacSimHit& hit, PacEmcCluster *cluster) const;

          Currently there is a trivial implementation for photons: 
             Building a PacEmcCluster with one PacEmcDigi whose energy is
             exactly equal to incident momentum of PacSimHit.

     - The plan is to use this class to look up appropriate TTrees (library)
       to sample clusters.


o  Test job  PacTest/testOneNeutral.cc

     - Run  testOneNeutral

       ...
       ...

Initial position
(0.19,0.39,0.22)
Initial momentum
(1,0,0;1)
[SimHit]
 SimHit 0: (109.999,0.39,0.22) effect 8 dmom 0.999882 element PacCylDetElem
Create a new EMC model 
The EMC Model : 
  Barrel radius is 110 cm
  Forward endcap begins at 0.2757  rad.
  Forward endcap ends at   0.469  rad.
  Barrel begins at         0.4695  rad.
  Barrel ends at         2.4574  rad.
  Forward endcap has 8 rings.
    which have 80  80  100  100  100  120  120  120   crystals.
  Barrel has 48 rings.
   each has 120 crystals.
  There are total of 820 crystals in the forward endcap.
  There are total of 5760 crystals in the barrel.

0xb704cdc0
0xb704cdc0
Found PacMeasurement::Calor
hit position (109.999,0.39,0.22)
5020 35 0
PacEmcClusterMeas::createEmcCluster
A PacEmcCluster: 
       energy = 1
    rawEnergy = 1
     position = (109.942,2.87892,2.13706)
  (theta, phi)= 1.55137 , 0.0261799
       nDigis = 1
PacEmcDigi: (35, 0)  = (1.55137,0.0261799) @ (109.942,2.87892,2.13706)  , Energy = 1



o  Root class for storing cluster samples in the library

class TEmcClusterLocal : public TObject {

public:

  TEmcClusterLocal();
  virtual ~TEmcClusterLocal();

  void clear();
  unsigned ndigis() { return _vphi.size(); }
  
  void setDigi(int theta, int phi, double energy) ;
  bool getDigi(unsigned n, int &theta, int &phi, double &energy);

private:

  std::vector< int > _vphi;
  std::vector< int > _vtheta;
  std::vector< double > _venergy;

  ClassDef(TEmcClusterLocal,1)
};



   - Simple jobs confirm that we can store TEmcClusterLocal as events in
     a TTree and read it back.