
    =========================================================
    Geant4 - an Object-Oriented Toolkit for Simulation in HEP
    =========================================================

                       Extended Example for G4RadioactiveDecay
                       -------------------- 

  The exRDM is created to show how to use the G4RadioactiveDecay process to simulate the decays of 
  radioactive isotopes as well as the induced radioactivity resulted from nuclear interactions. 

  In this example a simple geometry consists of a cylindric target placed in the centre of a tube detector 
  is constructed. Various primary event generation and tallying options are available. Further documentations 
  are available at

	  http://reat.space.qinetiq.com/septimess/exrdm

  1. GEOMETRY

     Material: There are 7 pre-defined materials: 
	"Vacuum" "Air" "Silicon" "Aluminium" "Lead" "Germanium" and "CsI"

     User can add a new material at the "PreIni" state, using the command
	/geometry/material/add

     For the geometry, the world is filled with "Air" and there are two components in it	     
 
       - Target:  A cylinder placed at the origin along the z-axis. The default size of the cylinder is 
	          0.5 cm radius and 1 cm in length, and its default material is "CsI".
		  
       - Detector:A tube cerntred at the origin along the z-axis, with inner radius matching the
	          radius of the target. The default thickness of the tube is 2 cm and it is  
                  5 cm long. The default material is "Germanium".

     The user can change the target/detector size and material at the at the "PreIni" state, using the 
     commands in the directory
		  
		/exrdm/det

  2. PHYSICS

     The following physics processes are included by default:

       - Standard electromagnetic:
           photo-electric effect
           Compton scattering
           pair production
           bremsstrahlung
           ionization
           multiple scattering
           annihilation

       - Decay

       - Radioactive Decay
	  By default it is applied through out the geometry. The user can limit it to just the target by 
	  commands

	        /grdm/noVolumes
	        /grdm/selectVolume Target

       - Hadronic processes:
	  Hadronic processes are not invoked by default. They can be activated by the user at the "PreIni" 
 	  state via the command

		/exrdm/phys/SelectPhysics

	  The options are:
 
		"Hadron" - Physicslist comsists of Binary_Cascade, HP_Neutron, QGSP, and LHEP, or
		the standdard hadron physics list avaible in the G4 distribution, i.e. 
		"QGSP_BERT", "QGSP_BIC", "QGSP_HP", "LHEP_BERT", "LHEP_BERT_HP", "LHEP_BIC",
		"LHEP_BIC_HP".

  3. EVENT:

     The event generator is based on the G4GeneralParticleSource (GPS) which allows the user to 
     control all aspects of the initial states of the events. In this example, however, only simple features 
     of the GPS are employed to generate the incident beam or the initial radio-isotopes. By default the 
     incident particle is travelling along the + z-axis and the incident position is at the -Z end 
     of the geometry.      

  4. DETECTOR RESPONSE:

     No Geant4 HITS and SD are defined in this example. If the variable "G4ANALYSIS_USE" is defined, all 
     the relevant information of the simulation is collected  at the "UserSteppingAction" stage. These 
     include:

       - Emission particles in the RadioactiveDecay process: 
           particle PDGcode,
           partilce kinetic energy,
	   particle creation time,
           particle weight.

	Note: the residual nuclei is not considered as an emitted particle.

       - Radio-Isotopes. All the radioactive isotopes produced in the simulation: 
           isotope  PDGcode,
           isotope  creation time,
           isotope  weight.
 
       - Energy depositions in the target and detector by prodicts of the RadioactiveDecay process: 
           energy depostion (positive volue for target and negative for detector), 
           time,
           weight.
  
  5. VISUALIZATION:
 
     Visualisation of the geometry and the tracks is possible with many of the G4 visualisation packages. An
     example of display the geometry and tracks using VRML is given in the macro file macros/vis.mac.  

  6. ANALYSIS:

     This example implements an AIDA-compliant analysis system as well as the ROOT system, for accumulating 
     and output histograms and ntuples. If the the user has an AIDA-compliant tool such as 
     AIDAJNI, ANAPHE, OpenScientist or PI installed, the analysis part of this example can 
     be activated by 
	
	setenv G4ANALYSIS_USE 1

     before building the executable.  

     The user can also use the executable with the ROOT system, if it is available. This is done by 
      
       setenv G4ANALYSIS_USE_ROOT 1
       
     again before the compilation. The AIDA and ROOT systems can be used individually, or in parallel 
     at the same time!

     If no analysis system is activated, there is no output file produced apart from the screen dump. 
     A file called "exrdm.aida" is produced by default for AIDA system and "exrdm.root" if the ROOT 
     system is selected. 
  
     The user can change the name of this output file with the command

	/histo/fileName new-filename

     The output AIDA file by default is in xml format. The AIDA system allows the use of other file format
     such as "root" and "hbook". User can change the output format to "hbook"  or "root" using the command 
     /histo/fileType.e.g.
	
	/histo/fileType hbook  
	/histo/fileType root
     
     When "root" format is selected for the AIDA system, the output AIDA file name is changed to 
     fileName_aida.root. This is to separate it from the the ROOT system output file fileName.root, in case 
     both systems are used.
    
     The output file, in "aida" or "hbook" or "root" format, conatins the 3 ntuples (100,200,300) which have 
     been described in section 4. In addition, there are 7 histograms in the file:

	histogram 10: The Pulse Height Spectrum (PHS) of the target.
	histogram 11: The PHS of the detector.
	histogram 12: The combined PHS of the target and detector.
	histogram 13: The anti-coincidece PHS of the target.
	histogram 14: The anti-coincidece PHS of the detector.
	histogram 15: The coincidece PHS between the target and detector.
	histogram 16: The emitted particle energy spectrum.

     The binnings of each histogram can be changed with the command 
        
        /histo/setHisto

     It is assumed the detector and target pulses both have an integration time of 1 microsecond, and the 
     gate is 2 microsecond for the coincidence spectrum. The target and detctor have a threshold of 10 keV 
     in the anti-/coincidence modes.        

     Histograms 10-15 were derived from the same data stored in ntuple-300(the energy depositions), while
     Histogram 16 is obtained with data in ntuple-100 (the emission particles). The user should be able to
     reproduce these histograms, or new histograms, with the ntuple data in an off-line analyis tool.

  7. GETTING STARTED:

     i) If you have an AIDA-compliant analysis system installed than you shall switch on the analysis part of
     example by 

	setenv G4ANALYSIS_USE 1
 
     in addition if you want to add the ROOT link to the ROOT system, do
       
        setenv G4ANALYSIS_USE_ROOT 1

     Otherwise make sure the G4ANALYSIS_USE and G4ANALYSIS_USE_ROOT are not definded
 
	unsetenv G4ANALYSIS_USE
	unsetenv G4ANALYSIS_USE_ROOT
	 
     ii) Build the exRDM executable:

         cd to exrdm
         gmake clean
         gmake

     Depends on the setup, gmake will create tmp and bin directories in your $G4TMP and $G4BIN directories. 
     The executable, named exRDM, will be in $G4BIN/$G4SYSTEM/ directory.

     iii) Run the executable: while in the exrdm directory do 

         $G4BIN/$G4SYSTEM/exRDM exrdm.in

     If all goes well, the execution shall be terminated in a few seconds. If G4ANALYSIS_USE is defined, one
     should see a "proton.aida" file created. If G4ANALYSIS_USE_ROOT is defined, there will be 
     a proton.root file in the same directory.

 8. FURTHER EXAMPLES:

    There are a number of g4mac files in the ./macros subdirectory, to show the features of the 
    G4RadioactiveDecay process. Most of them will lead to the creation of an aida file in the same name 
    of the micro file, which can be examed and analysed with an analysis tool such as OpenScientist ,or JAS3.
 
	vrml.mac:  to visulise the geometry and the incident of one 100 MeV Cf240 isotope and its decay. A vrml
             	   file (g4_xx.vrml) is created at the end. If a default vrml viewer has been set, one shall  
                   see the geometru and track displayed automatically.

	u238c.mac: shows the decays of the U238 chain in analogue MC mode.

	th234c-b.mac: shows the decays of Th234 in variance reduction MC mode. All its secondaies in along the 
          	      decay chains are generated. The default source profile and decay biasing schemes are used
	              to determine the decay times and weights of the secondaries.

	proton-1gev.mac: simulation of 1 GeV protons incident on a lead target. The decays of the radio-siotopes 
        		 created in the proton-lead interactions are simulated with RadioactiveDecay in analogue 
                         MC mode.   

	proton-b.mac: same as proton-1geV.mac, but the decays of the radio-siotopes created in the  proton-lead 
 		      interactions are simulated with RadioactiveDecay in variance reduction MC mode. The isotopes 
		      and those along the decay chains are forced to decay in the time windows specified by the 
                      user in file measures.data, and the weights of the decay products are determined by the 
                      beam profile as defined in the beam.data file and their decay times. 

   	one-iso.mac: simple macro file to show how to simulate the decay of a specific radio-isotope. User can 
		     edit it to simulate which ever isotope he/she likes to try.

	neutron.mac: macrofile to show the incident of low energy neutrons on an user specified NaI target and 
		     the decays of the induced radio-isotopes. This shows how to define a new material in exrdm.

	ne24.mac: this shows the decays of Ne-24 to Na-24 in variance reduction MC mode. Further decays of Na-24 
                  are not simulated by applying the nucleuslimits in RadioactiveDecay. Two runs are carried out.
		  One with the bracjing ratio biasing applied and one without. 

	multiple-source.mac: to show the decays of different isotopes uniformly distributed through the target 
 			     volume in a single run. 

	isotopes.mac: to show the decays of a number of different isotopes in a single macro file.


	f24.mac: to show the different treatments one can apply to the decays of F24. i) the complete decay chain 
		 from F24 to Mg24, in analogue mode; ii) the complete chain, but in variance reduction mode; 
                 iii) restrict to the decay of F24 only in analogue mode; iv) restrict to the decay of F24 only but
                 in variance reduction mode.

	as74.mac: The decays of As74 which has a rather complicated decay scheme. i) in analogue MC mode; ii) in 
		  variance reduction MC mode.

	test.mac: macro used to check if the right physics processes are assigned to different particles.
  
