
     =========================================================
              Geant4 - ULTRA-based air shower example
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                             README
                      ---------------------

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----> Introduction.                                                     
                                                                          
The ULTRA detector is a hybrid 2-component system consisting of:                                  
                                                                        
                                                                        
1) an UV detection system - the UVscope                                 
2) an array of scintillator detectors - the ETscope                      
                                                                        
The UVscope detects Cherenkov light associated to cosmic ray showers    
when it is diffusively reflected on ground.                             
The ETscope detects in coincidence the charged particles of the shower. 
                                                                        
In the current version only the UVscope simulation is included          
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----> Description                                                       
                                                                        
The UVscope consists of a Fresnel lens and a PMT located in the focal   
plane, enclosed in a cylindrical aluminum housing. The lens is 457 mm   
in diameter and is made of UV transmitting acrylic with 5.6 grooves     
per mm. The description of the geometry of the Fresnel lens makes use   
of object parameterisation/replication capabilities.                     
                                                                      
The primary vertex generator describes a plane circular source of UV 
(3eV, about 400 nm) optical photons.                                    
Depending on the selected detector configuration, the source can be     
positioned such that the photons are fired                              
to a reflecting surface or, by default, directly to the UVscope 
(no reflecting surface is present in this case).                        
Reflection at the surface can be chosen to be specular or diffuse.
In both cases the normal to the surface makes an angle of 45 degrees    
with the UVscope axis and the photons are emitted at an angle of 
90 degrees with the UVscope axis.                                       
If none of these variables is set no reflecting surface is used 
and the photons source is positioned at the UVscope axis. 
                                                                        
The definition of the relevant optical boundaries, parameters and       
processes is made.                                                      
                                                                        
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----> SET-UP 
                                                                        
A standard Geant4 example GNUmakefile and a CMakeLists.txt file are 
provided, for building with cmake                                       

The following environment variable can be set in order to get           
additional verbosity during program running:                            

 1) GNUmakefile

  setenv ULTRA_VERBOSE 

or 

 2) cmake -DULTRA_VERBOSE=ON "path to source"


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The analysis is performed using the native Geant4 analysis tools 
(g4tools). In the default case, the output histograms are written 
in a ROOT file.

The output file can be written in other formats (csv, xml, hdf5) by
changing the G4AnalysisManager default file type in UltraRunAction::BeginOfRunAction().

-----------------------------------------------------------------------
----> How to run the example.                                          

  From the directory where the Ultra binary resides :

  ./Ultra "macro name" for running in batch mode                       
                                                                                                                    
  ./Ultra  for running in interative mode.                             
  The macro VisDirect.mac is executed.                                 
                                                                        
  Several macros are available for interactive visualisation.          
  While in interactive mode type the command                           
  /control/execute "name_of_macro", 
  where "name_of_macro" is one of the following:

  Direct.mac - a beam of photons is shot directly to the telescope.    
  Mirror.mac - the beam is directed to a specular reflecing surface    
  Ground.mac - the beam is directed to a diffusively reflecting surface

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----> Simulation output                                                 

the output is ultra.root 		                             
 It contains:
 1)1Dhistogram with the detected photons energy (eV)                    
 2)1Dhistogram with the number of detected photons per event            


To plot these histograms run the ROOT macro 'do_plots.C' :
> root do_plots.C
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for comments and questions: bernardo@lip.pt
for more info http://www.ge.infn.it/geant4/examples/

last modified:  B. Tome 08/11/2019
created by   :  B. Tome and M.C. Espirito Santo 20/05/2004
