$Id: README,v 1.3 2008/09/26 20:15:04 maire Exp $
-------------------------------------------------------------------

     =========================================================
     Geant4 - an Object-Oriented Toolkit for Simulation in HEP
     =========================================================

                            TestEm17
                            --------
        This example is intended to check implementation of the processes 
        of muon interactions: ionization, direct (e+,e-) production,
	bremsstrahlung, mu-nuclear interaction.
	It allows to compute differential cross sections (as function of the
	energy tranfered to secondaries), total cross sections and to compare
	with analytic calculations.
	
 1- GEOMETRY DEFINITION
 
 	It is a single box of homogeneous medium.
 	Two parameters define the geometry :
 	- the material of the box,
	- the (full) size of the box.
 	
 	The default geometry (1 m of Iron) is constructed in 
	DetectorConstruction, but the above parameters can be changed 
	interactively via the commands defined in DetectorMessenger.
 	
 2- PHYSICS LIST
 
 	The physics list contains only electromagnetic processes for muon,
	adding G4MuNuclearInteraction and seting of upper energy range limit 
	to 1000 PeV).
	 
        Standard (default) and g4v52 (frozen at the release Geant4 v.5.2) 
	physics can be choosen.
	 	 
 3- AN EVENT : THE PRIMARY GENERATOR
 
 	The primary kinematic consists of a single particle starting at the edge
	of the box. The type of the particle and its energy are set in 
	PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4 
 	build-in commands of ParticleGun class (see the macros provided with 
 	this example).
 	
 4- PHYSICS
 
	The incident particle is a muon. During the tracking, secondary
	particles are killed.
	
	The number of interactions are plotted as a function of the energy 
	transfered to the secondaries.
	The total number of interactions is recorded, and the total crossSection
	computed from this.  

        At EndOfRun, the above results are compared with analytic calculations.
	The functions which compute the theoritical crossSections have been
	provided by the G4 MEPhI group, and grouped in MuCrossSection class.

 5- HISTOGRAMS
         
	The test contains 4 built-in 1D histograms, which are managed by the
	HistoManager class and its Messenger.

        1 Monte-Carlo relative transferred energy distribution histo
            (log10(eps/Emu kin) for knock-on electrons (ionization)
        2  -"- direct (e+,e-) pair production
        3  -"- bremsstrahlung
        4  -"- nuclear interaction
	
	The histos can be activated individually with the command :
	/testem/histo/setHisto id nbBins  valMin valMax : min and max values of 
                                                          log10(eps/Emu kin).
	
	At EndOfRun the corresponding histos for analytic calculations are
	automatically created anf filled (histo 6 to 9), and the comparison
	(G4 divided by theory) is done in histos 11 to 14.
							  
 	One can control the name and the type of the histograms file with 
	the commands:
 	/testem/histo/setFileName  name  (default testem17)
   	/testem/histo/setFileType  name  (default root)

	Note that, by default, histograms are disabled. To activate them, 
	uncomment the flag G4ANALYSIS_USE in GNUmakefile. 	
 	 				
 6- VISUALIZATION
 
 	The Visualization Manager is set in the main().
 	The initialisation of the drawing is done via the commands
 	/vis/... in the macro vis.mac. To get visualisation:
 	> /control/execute vis.mac
 	
 	The detector has a default view which is a longitudinal view of the 
 	box.
 	
 	The tracks are drawn at the end of event, and erased at the end of run.
	
 7- HOW TO START ?
 
	compile and link to generate an executable
 		% cd geant4/examples/extended/electromagnetic/TestEm17
 		% gmake
 		
	execute TestEm17 in 'batch' mode from macro files :
 		% TestEm17   allproc.mac
 		
	execute TestEm17 in 'interactive mode' with visualization :
 		% TestEm17
		Idle> control/execute vis.mac
 		....
 		Idle> type your commands
 		....
 		Idle> exit

  8- USING HISTOGRAMS
 
  By default the histograms are not activated. To activate histograms
  the environment variable G4ANALYSIS_USE should be defined. For instance
  uncomment the flag G4ANALYSIS_USE in GNUmakefile.
  
  Before compilation of the example it is optimal to clean up old files:
  	gmake histclean
  	gmake
	 
  To use histograms, at least one of the AIDA implementations should be 
  available. See InstallAida.txt
  
