geant4

$Id: README,v 1.21 2006/05/15 14:38:15 maire Exp $
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     Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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                            TestEm1
                            -------
  How to count processes.
  How to activate/inactivate processes.
  How to survey the tracking, in perticular the range of charged particles.
  How to define a maximum step size.
	
 1 - GEOMETRY DEFINITION
 
  It is a simple box which represente an 'semi infinite' homogeneous medium.
 	
  Two parameters define the geometry :
   - the material of the box,
   - the full size of the box.
	 	
  In addition a transverse uniform magnetic field can be applied.
 	
  The default geometry is constructed in DetectorConstruction class, but all of 
  the above parameters can be changed interactively via the commands defined in 
  the DetectorMessenger class.
 	
 2 - PHYSICS LIST
 
  The particle list is the one of novice/exampleN03.
  The physics list contains the 'standard' electromagnetic processes, and decay.
 		
  Few commands have been added to PhysicsList, in order to set the production 
  threshold for secondaries for gamma and e-/e+.
 	 
 3 - AN EVENT : THE PRIMARY GENERATOR
 
  The primary kinematic consists of a single particle starting at the left face 
  of the box. The type of the particle and its energy are set in the 
  PrimaryGeneratorAction class, and can be changed via the G4 build-in commands 
  of ParticleGun class (see the macros provided with this example).
	
  In addition one can choose randomly the impact point of the incident particle.
  The corresponding interactive command is built in PrimaryGeneratorMessenger.	
 				
 4 - 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.
  Optionaly one can choose to draw all particles, only the charged, or none. 
  This command is defined in EventActionMessenger class.
 	
 5 - PHYSICS SURVEY
 
  The particle's type and the physic processes which will be available in this 
  example are set in PhysicsList class.
 	
  A set of macros defining various run conditions are provided. The processes 
  are actived/inactived together with differents cuts, in order to survey the 
  processes one by one.

  The number of produced secondaries are counted, the number of steps, and the 
  number of process calls responsible of the step.
 	
 6 - HOW TO START ?
 
  - compile and link to generate an executable
	% cd geant4/examples/extended/electromagnetic/TestEm1
	% gmake
 		
  - execute TestEm1 in 'batch' mode from macro files
	% TestEm1   run10.mac
 		
  - execute TestEm1 in 'interactive mode' with visualization
	% TestEm1
	....
	Idle> type your commands
	....
	Idle> exit
		
 7 - TRACKING : StepMax
 
  In order to control the accuracy of the deposition, the user can limit
  'by hand' the maximum  step size of charged particles.
  As an example, this limitation is implemented as a 'full' process :
  see StepMax class and its Messenger. The 'StepMax process' is registered
  in the Physics List. 
  	
 8 - HISTOGRAMS
 
  Testem1 produces several histo which are saved as testem1.hbook by default.
  Content of these histo:  
      1 : track length of primary particle
      2 : number of steps primary particle
      3 : step size of primary particle

  Note that, by default, histograms are disabled. To activate them, uncomment
  the flag G4ANALYSIS_USE in GNUmakefile.
 
  Before compilation of the example it is optimal to clean up old files:
  	gmake histclean
  	gmake 

 9 - USING HISTOGRAMS

  To use histograms, at least one of the AIDA implementations should be 
  available (see http://aida.freehep.org).
  
 9a - PI 

  A package including AIDA and extended interfaces also using Python is PI, 
  available from: http://cern.ch/pi

  Once installed PI or PI-Lite in a specified local area $MYPY, it is required 
  to add the installation path to $PATH, i.e. for example, for release 1.2.1 of 
  PI:
  setenv PATH ${PATH}:$MYPI/1.2.1/app/releases/PI/PI_1_2_1/rh73_gcc32/bin

  CERN users can use the PATH to the LCG area on AFS.
  Before running the example the command should be issued:
  eval `aida-config --runtime csh`

 9b -  OpenScientist

  OpenScientist is available at http://OpenScientist.lal.in2p3.fr.

  You have to "setup" the OpenScientist AIDA implementation before compiling
  (then with G4ANALYSIS_USE set) and running your Geant4 application.

 On UNIX you setup, with a csh flavoured shell : 
	csh> source <<OpenScientist install path>/aida-setup.csh 
        or with a sh flavoured shell : 
	sh> . <<OpenScientist install path>/aida-setup.sh
 On Windows : 
	DOS> call <<OpenScientist install path>/aida-setup.bat 

  You can use various file formats for writing (AIDA-XML, hbook, root).
  These formats are readable by the Lab onx interactive program
  or the OpenPAW application. See the web pages.


  With OpenPAW, on a run.hbook file, one can view the histograms
  with something like :
	OS> opaw 
        opaw> h/file 1 run.hbook  ( or opaw> h/file 1 run.aida or run.root)  
	opaw> zone 2 2 
	opaw> h/plot 1 
	opaw> h/plot 2