//$Id$

///\file "electromagnetic/TestEm3/.README.txt"
///\brief Example TestEm3 README page

/*! \page ExampleTestEm3 Example TestEm3

 - How to collect energy deposition in a sampling calorimeter.
 - How to survey energy flow.
 - How to print stopping power. 

\section TestEm3_s1 GEOMETRY DEFINITION
 
  The calorimeter is a box made of a given number of layers.
  A layer consists of a sequence of various absorbers (maximum MaxAbsor=9).
  The layer is replicated.
 
  Parameters defining the calorimeter :
    - the number of layers,
    - the number of absorbers within a layer,		
    - the material of the absorbers,
    - the thickness of the absorbers,
    - the transverse size of the calorimeter (the input face is a square). 
 
  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 modified interactively via the commands 
  defined in the DetectorMessenger class.
  
<pre>
        |<----layer 0---------->|<----layer 1---------->|<----layer 2---------->|
        |           |           |                       |                       |
        ==========================================================================
        ||          |           ||          |           ||          |           ||
        ||          |           ||          |           ||          |           ||
        ||   abs 1  | abs 2     ||   abs 1  | abs 2     ||   abs 1  | abs 2     ||
        ||          |           ||          |           ||          |           ||
        ||          |           ||          |           ||          |           ||
 beam   ||          |           ||          |           ||          |           ||
======> ||          |           ||          |           ||          |           ||
        ||          |           ||          |           ||          |           ||
        ||          |           ||          |           ||          |           ||
        ||          |           ||          |           ||          |           ||
        ||          |           ||          |           ||          |           ||
        ||   cell 1 | cell 2    ||   cell 3 | cell 4    ||   cell 5 | cell 6    ||
        ==========================================================================
        ^           ^           ^           ^           ^           ^           ^
        pln1        pln2        pln3       pln4        pln5        pln6       pln7
 </pre>
 
  NB. The number of absorbers and the number of layers can be set to 1.
  In this case we have a unique homogeneous block of matter, which looks like 
  a bubble chamber rather than a calorimeter ...
  (see the macro emtutor.mac)
  
\section TestEm3_s2 PHYSICS LISTS

  Physics lists are based on modular design. Several modules are instantiated:
  1. Transportation
  2. EM physics
  3. Decays
  4. StepMax - for step limitation

  EM physics builders can be local (eg. in this example) or from G4 kernel
  physics_lists subdirectory.

  Local physics builders:
  - "local" standard EM physics with current 'best' options setting.
              these options are explicited in PhysListEmStandard

  From geant4/source/physics_lists/builders:   
  - "emstandard_opt0" recommended standard EM physics for LHC
  - "emstandard_opt1" best CPU performance standard physics for LHC
  - "emstandard_opt2" similar fast simulation
  - "emstandard_opt3" best standard EM options - analog to "local" above
  - "emstandard_opt4" best current advanced EM options standard + lowenergy
  - "emstandardWVI" standard EM physics and WentzelVI multiple scattering
  - "emstandardSS"  standard EM physics and single scattering model
  - "emlivermore"  low-energy EM physics using Livermore data
  - "empenelope"   low-energy EM physics implementing Penelope models
  - "emlowenergy"  low-energy EM physics implementing experimental
                    low-energy models
      
  Physics lists and options can be (re)set with UI commands
  
  Please, notice that options set through G4EmProcessOptions are global, eg
  for all particle types. In G4 builders, it is shown how to set options per
  particle type.
        	    
\section TestEm3_s3 AN EVENT : THE PRIMARY GENERATOR
 
  The primary kinematic consists of a single particle which hits the calorimeter
  perpendicular to the input face. 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 G4ParticleGun 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.
 
  A RUN is a set of events.
  
  TestEm3 computes the energy deposited per absorber and the energy flow through
  the calorimeter.
 
\section TestEm3_s4 VISUALIZATION
 
  The Visualization Manager is set in the main() (see TestEm3.cc).
  The initialisation of the drawing is done via the commands :
  /vis/... in the macro vis.mac. In interactive session:
\verbatim
  PreInit or Idle > /control/execute vis.mac
\endverbatim
 
  The default view is a longitudinal view of the calorimeter.
 
  The tracks are drawn at the end of event, and erased at the end of run.
  Optionally one can choose to draw all particles, only the charged ones, or
  none. This command is defined in EventActionMessenger class.
 
\section TestEm3_s5 PHYSICS DEMO
 
  The particle's type and the physics processes which will be available
  in this example are set in PhysicsList class.
 
  In addition a built-in interactive command (/process/inactivate processName)
  allows to activate/inactivate the processes one by one.
  Then one can well visualize the processes one by one, especially 
  in the bubble chamber setup with a transverse magnetic field.
 
  As a homework try to visualize a gamma conversion alone, 
  or the effect of the multiple scattering.

  Notice that one can control the maximum step size in each absorber, via the
  StepMax process and the command 
\verbatim
/testem/stepMax/absorber  
\endverbatim
  (see StepMax and PhysicsList classes)
 
\section TestEm3_s6 HOW TO START ?
 
  - Execute TestEm3 in 'batch' mode from macro files
\verbatim
% TestEm3   run01.mac
\endverbatim
 
  - Execute TestEm3 in 'interactive mode' with visualization
\verbatim
% TestEm3
....
Idle> type your commands. For instance:
Idle> /control/execute run01.mac
....
Idle> exit
\endverbatim
 
\section TestEm3_s7 HISTOGRAMS
 
 Testem3 can produce histograms : 
  - histo 1 : energy deposit in absorber 1
  - histo 2 : energy deposit in absorber 2
  - etc.
  
 One can control the binning of the histo with the command:
\verbatim
/analysis/h1/set   idAbsor  nbin  Emin  Emax  unit 
\endverbatim
  etc.,  
  where unit is the desired energy unit for that histo (see TestEm3.in).
  
  - histo 11 : longitudinal profile of energy deposit in absorber 1 (MeV/event)
  - histo 12 : longitudinal profile of energy deposit in absorber 2 (MeV/event)  
  - etc.
  
  histo 21 : energy flow (MeV/event)
  histo 22 : lateral energy leak (MeV/event)  
  
  NB. Numbering scheme for histograms:
  - layer     : from 1 to NbOfLayers (inclued)
  - absorbers : from 1 to NbOfAbsor (inclued)
  - planes    : from 1 to NbOfLayers*NbOfAbsor + 1 (inclued)
        
  One can control the name of the histograms file with the command:
\verbatim
/analysis/setFileName  name  (default testem3)
\endverbatim
   
  It is possible to choose the format of the histogram file : root (default),
  hbook, xml, csv, by using namespace in HistoManager.hh 
 
 It is also possible to print selected histograms on an ascii file:
\verbatim
/analysis/h1/setAscii id
 \endverbatim
 All selected histos will be written on a file name.ascii  (default testem3)
    
\subsection TestEm3_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 HistoManager.hh
  
*/
