
               **************
               ***  DEMO  ***
               **************

 --- MAIN : run 1 event only and in batch (neither detector 
     or event display, nor any type of textual or graphical 
     user interface)


 --- DETECTOR : only the experimental Hall. 
     which is a 4m x 4m x 4m box, filled with gas Argon.

        gas Argon:        Z = 18
                          A = 39.95  g/mole
                    density = 1.782e-03 g/cm3


 --- PHYSICS : only geantino particle with only transportation 
     process (which is the only possible process for geantino).


 --- PRIMARY GENERATOR : use G4ParticleGun, shoots 1 geantino
     of 10 GeV, along the beam line (x-axis), from the position -1 m.


