
///\file "medical/fanoCavity/.README.txt"
///\brief Example fanoCavity README page

/*! \page ExamplefanoCavity Example fanoCavity

 This program computes the dose deposited in an ionization chamber by a
 monoenergetic photon beam.
 The geometry of the chamber satisfies the conditions of charged particle
 equilibrium. Hence, under idealized conditions, the ratio of the dose 
 deposited over the beam energy fluence must be equal to the 
 mass_energy_transfer coefficient of the wall material.
 
 E.Poon and al, Phys. Med. Biol. 50 (2005) 681 \n
 I.Kawrakow, Med. Phys. 27-3 (2000) 499 \n

\section ExamplefanoCavity_s1 GEOMETRY
 
 The chamber is modelized as a cylinder with a cavity in it.
 
 6 parameters define the geometry :
   - the material of the wall of the chamber
   - the radius of the chamber and the thickness of the wall
   - the material of the cavity
   - the radius and the thickness of the cavity

 Wall and cavity must be made of the same material, but with different
 density
 
 All above parameters can be redifined via the UI commands built in 
 DetectorMessenger class
<pre>
                    -----------------
                    |               |
                    | wall          |
                    |     -----     |
                    |     |   |     |
                    |     | <-+-----+--- cavity
         ------>    |     |   |     |
         ------>    |     |   |     |
   beam     -------------------------------- cylinder axis
         ------>    |     |   |     |
         ------>    |     |   |     |
                    |     |   |     |
                    |     |   |     |
                    |     -----     |
                    |               |
                    |               |
                    -----------------

</pre>

\section ExamplefanoCavity_s2 BEAM
  
 Monoenergetic incident photon beam is uniformly distribued, perpendicular 
 to the flat end of the chamber. The beam radius can be controled with an
 UI command built in PrimaryGeneratorMessenger; the default is full wall 
 chamber radius.
 
 Beam regeneration : after each Compton interaction, the scattered photon is
 reset to its initial state, energy and direction. Consequently, interaction
 sites are uniformly distribued within the wall material.
 
 This modification must be done in the ParticleChange of the final state 
 of the Compton scattering interaction. Therefore, a specific model
 (MyKleinNishinaCompton) is assigned to the ComptonScattering process in
 PhysicsList. MyKleinNishinaCompton inherites from G4KleinNishinaCompton;
 only the function SampleSecondaries() is overwritten.
 
\section ExamplefanoCavity_s3 PURPOSE OF THE PROGRAM
 
 The program computes the dose deposited in the cavity and the ratio
 Dose/Beam_energy_fluence. This ratio is compared to the mass_energy_transfer
 coefficient of the wall material.
 
 The mass_energy_transfer coefficient needs :
 - the photon total cross section, which is read from the PhysicsTables
 by G4EmCalculator (see EndOfRunAction).
 - the average kinetic energy of charged secondaries generated in the
 wall during the run. 
 
 The program needs high statistic to reach precision on the computed dose.
 The UI command /testem/event/printModulo allows to survey the convergence of
 the kineticEnergy and dose calculations.
 
 In addition, to increase the program efficiency, the secondary particles
 which have no chance to reach the cavity are immediately killed (see
 StackinAction). This feature can be switched off by an UI command (see
 StackingMessenger).
 
 The simplest way to study the effect of e- tracking parameters on dose 
 deposition is to use the command /testem/stepMax.
 
\section ExamplefanoCavity_s4 PHYSICS
 
 The physics lists contains the standard electromagnetic processes, with few 
 modifications listed here.
 
 - Compton scattering : as explained above, the final state is modified in
 MyKleinNishinaCompton class.
 \n\n
 In order to make the program more efficient, one can increase the Compton
 cross section via the function SetCSFactor(factor) and its 
 associated UI command. Default is factor=1000.
 
 - Bremsstrahlung : Fano conditions imply no energy transfer via
 bremsstrahlung radiation. Therefore this process is not registered in the
 physics list. However, it is always possible to include it.
 See PhysListEmStandard class.
 
 - Ionisation : In order to have same stopping power in wall and cavity, one
 must cancel the density correction term in the dedx formula. This is done in
 a specific MollerBhabha model (MyMollerBhabhaModel) which inherites from 
 G4MollerBhabhaModel.
 \n\n
 To prevent explicit generation of delta-rays, the default production
 threshold (i.e. cut) is set to 10 km (CSDA condition).
 \n\n
 The finalRange of the step function is set to 10 um, which more on less
 correspond to a tracking cut in water of about 20 keV. See emOptions.
 Once again, the above parameters can be controled via UI commands.
 
 - Multiple scattering : is switched in single Coulomb scattering mode near
 boundaries. This is selected via EM options in PhysicsList, and can be
 controled with UI commands.
 
 - All PhysicsTables are built with 100 bins per decade.  
 
\section ExamplefanoCavity_s5 HISTOGRAMS
 
  fanoCavity has several predefined 1D histograms : 
  -  1 : emission point of e+-
  -  2 : energy spectrum of e+-
  -  3 : theta distribution of e+-
  -  4 : emission point of e+- hitting cavity
  -  5 : energy spectrum of e+- when entering in cavity
  -  6 : theta distribution of e+- before enter in cavity
  -  7 : theta distribution of e+- at first step in cavity      
  -  8 : track segment of e+- in cavity
  -  9 : step size of e+- in wall
  - 10 : step size of e+- in cavity
  - 11 : energy deposit in cavity per track     
      
  The histograms are managed by G4AnalysisManager class and its messenger. 
  The histos can be individually activated with the command :
\verbatim
/analysis/h1/set id nbBins  valMin valMax unit 
\endverbatim
  where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
  
   One can control the name of the histograms file with the command:
\verbatim
/analysis/setFileName  name  (default fanoCavity)
\endverbatim
   
   It is possible to choose the format of the histogram file :
   root(default), xml, hbook.  See 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 fanocavity)
 
\section ExamplefanoCavity_s6 HOW TO START ?
 
 - Execute fanoCavity in 'batch' mode from macro files
\verbatim
% fanoCavity   run01.mac
\endverbatim
 
 - Execute fanoCavity in 'interactive mode' with visualization
\verbatim
% fanoCavity
....
Idle> type your commands
....
Idle> exit
\endverbatim

*/
