
///\file "electromagnetic/TestEm4/.README.txt"
///\brief Example TestEm4 README page

/*! \page ExampleTestEm4 Example TestEm4

 Plot energy deposited by 9 MeV photon beam in an homogeneous medium.
	
\section TestEm4_s1 GEOMETRY DEFINITION
 
 It is a cylinder of 5 cm radius filled with C6F6.
 	
\section TestEm4_s2 PHYSICS LIST
 
 The particle list contains only gamma, electron,positron.
 The physics list contains the 'standard' electromagnetic processes.
 	 
\section TestEm4_s3 AN EVENT : THE PRIMARY GENERATOR
 
 The primary kinematic is a single 9 MeV gamma randomly shooted at the
 middle of the cylinder. 
 	 				
\section TestEm4_s4 VISUALIZATION
 
 The Visualization Manager is set in the main () (see TestEm4.cc).
 The initialisation of the drawing is done via the commands
 /vis/.. in the macro vis.mac. This macro is
 automatically read from the main in case of interactive running mode.
 
 The detector has a default view which is a transversal 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.
 	
\section TestEm4_s5 PHYSICS SURVEY
 
 The energy deposited in C6F6 is histogramed.
 	
\section TestEm4_s6 HOW TO START ?
 
 - Execute TestEm4 in 'batch' mode from macro files
\verbatim
% TestEm4   TestEm4.in
\endverbatim
  		
 - Execute TestEm4 in 'interactive mode' with visualization
\verbatim
% TestEm4
....
Idle> type your commands
....
Idle> exit
\endverbatim
  		
 - Visualize the histogram (paw)
\verbatim
paw> h/file 1 testem4.hbook
paw> option stat
paw> option logy
paw> h/pl 1 	
\endverbatim
   

\section TestEm4_s7 USING HISTOGRAMS

 The format of the histogram file can be : root (default),
 hbook, xml, csv, by selecting g4nnn.hh in RunAction.hh 
 
\subsection TestEm4_subs1 Using hbook format
 
 Need a special treatement : the Cern Library must be installed and the
 environment variable CERNLIB correctly set. Then, *before* compiling,
 activate G4_USE_HBOOK in GNUmakefile and g4hbook.hh in RunAction.hh
  
\section TestEm4_s8- RANDOM NUMBERS HANDLING
 
   CLHEP provides several random number engines. In this example the Ranecu
   engine is choosen at beginning of the main (TestEm4.cc).
	
   By default, G4RunManager does not save the rndm seed.
   To do so the user must set in BeginOfRunAction:
   G4RunManager::GetRunManager()->SetRandomNumberStore(true);
	
   Then the rndm seed is systematically saved at beginning of run
   (currentRun.rndm) and beginning of event (currentEvent.rndm)
   Therefore, in case of abnormal end, the seed of the last event processed
   is available in currentEvent.rndm
	
   Even in case of normal run processing, the user may wish to preserve the
   rndm seed of selected events. At any time in the event, put the
   following statement:
\verbatim
if (condition) G4RunManager::GetRunManager()->rndmSaveThisEvent();
\endverbatim
   currentEvent.rndm will be copied to runXXevntYY.rndm
   (see SteppingAction::UserSteppingAction() )
	
   To restart a run from a given rndm seed, use the UI command :
\verbatim
/random/resetEngineFrom  fileName 
\endverbatim
	
   The macro rndmSeed.mac shows how to save and reset the random number
   seed between runs, from UI commands.	

*/
  
