$Id: README,v 1.1 1999/10/11 15:08:24 maire Exp $
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     =========================================================
     Geant4 - an Object-Oriented Toolkit for Simulation in HEP
     =========================================================

                            TestEm2
                            -------
     This example allows to do the shower development of an single primary
     particle, and to survey the physics processes which occur,
     with printing and visualization.
	
 1- GEOMETRY DEFINITION
 
     The geometry consists of a cylinder of homegenous material.
     This cylinder is replicated longitudinaly (slice) and radialy (ring).
  
     The default geometry is constructed in DetectorConstruction class,
     but all of the above parameters can be modified interactively via
     the commands defined in the DetectorMessenger class.
  
     Material can be choosen: Air Water lAr Al Fe BGO PbWO4 Pb.
     eg: /calor/setMat PbWO4
      
     The size of the slices and rings are expressed in radiation length units
     and can be changed.
     eg: /calor/setLbin 20   1.    ---> 20 slices of 1. radl
         /calor/setRbin  5   0.25  --->  5 rings of 0.25 radl
         /calor/update             ---> rebuild the geometry
      
     An uniform magnetic field along the cylinder axis can be set.
     eg: /calor/setField 5 tesla 
 	    
 2- AN EVENT : THE PRIMARY GENERATOR
 
     The primary kinematic consists of a single particle which hits the
     cylinder perpendicular to the input face. The type of the particle
     and its energy are set in the PrimaryGeneratorAction class, and can
     changed via the G4 build-in commands of ParticleGun class (see
     the macros provided with this example).
 	
     A RUN is a set of events.
 				
 3- VISUALIZATION
 
     The Visualization Manager is set in the main().
     The initialisation of the drawing is done via the command
     /vis~/create_view in the macro init.mac. This macro is
     automatically read from the main in case of interactive running mode.
 	
     The detector has a default view which is a longitudinal view of the 
     cylinder.
 	
     The tracks are drawn at the end of event, and erased at the end of run.
     Optionaly one can choose to draw all particles, only the charged one,
     or none. This command is defined in EventActionMessenger class.
 	
 4- PHYSICS DEMO
 
     The particle's type and the physic processes which will be available
     in this example are set in PhysicsList class.
 	
     In addition a build-in interactive command (/process/inactivate proname)
     allows to activate/inactivate the processes one by one.
     
     The threshold for producing secondaries can be changed.
     eg: /run/particle/setCut 100 microm
         /run/initialize
	  	
 5- HOW TO START ?
 
     - compile and link to generate an executable
 		% cd TestEm2
 		% gmake
 		
     - execute TestEm2 in 'batch' mode from macro files
 		% TestEm2   run01.mac
 		
     - execute TestEm2 in 'interactive mode' with visualization
 		% TestEm2
 		....
 		Idle> type your commands. For instance:
 		Idle> /control/execute newgeom.mac
 		....
 		Idle> exit
 	
 7- HISTOGRAMS
 
     Testem2 produces several histo which are saved as testem2.histo
     under the control of the command /run/save on
     
     Content of these histo:
  
      1 : energy deposit       per event
      2 : charged track length per event
      3 : neutral track length per event
            
      4 : longitudinal energy profile
      5 : cumulated longitudinal energy profile
      6 : rms of cumulated longitudinal energy profile
      
      7 : gamma's flux
      8 : positron's flux
      9 : electron's flux
                      
     10 : radial energy profile    
     11 : cumulated radial energy profile
     12 : rms of cumulated radial energy profile
   
