$Id: README,v 1.1 2003/11/07 21:30:27 japost Exp $
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     =========================================================
     Geant4 - an Object-Oriented Toolkit for Simulation in HEP
     =========================================================

                            ExampleNTST
                            -----------

	This example simulates the BaBar silicon vertex tracker and 40-layer
        drift chamber. This example also runs either the standard G4 
        transportation code (default) or BgsG4Extension (files in src/
        and include/ prepended with 'Bgs').
	
 1- GEOMETRY DEFINITION

        The geometry consists of the active elements (wafers) of the BaBar
        silicon vertex tracker (SVT) and the 40-layer drift chamber (DCH). 
        There is a detector messenger class (NTSTDetectorMessenger) to set 
	geometry options. 

	Command directory path : /NTST/

	Guidance :
	NTST detector control.

	 Sub-directories : 
	 Commands : 
	   setInputFile * Set input file name
	   disable * disable detetector
	   setDebug * Set debug flag.
	   setNSubLayer * Set the number of SVT sublayers.
	   setOuterRadius * Set outer radius of the SVT mother volume
	   getFieldStats * Return number calls to field routine
 	    
 2- GENERATORS

	There is a generator action class which generates events according
	to two possible generators and optionally print the event. 
	The generator and print options are controlled by 
	NTSTGeneratorMessenger class, which has the following options
	available:

 	Commands : 
   	choose * Choose the generator to use.
   	print * print events (true) or not (false).

	There are currently two generators available for use: 

	- NTSTGunGenerator ('gun'):
	generates single particle events containing 1 or more particles of a 
	specified type over a range of momenta and solid angle. This class
	has an associated messenger, NTSTGunMessenger, which allows the user 
        to issue the commands :
 
	   List * List available particles.
	   particle * Set particle to be generated.
	   vertex * Set vertex position (with unit, def: mm).
	   spotsize * Set vertex size (with unit, def: mm).
	   plow * Set low momentum limit (with unit, def: GeV).
 	   phigh * Set high momentum limit (with unit, def: GeV).
	   coslow * Set lower cosine limit.
	   coshigh * Set upper cosine limit.
	   philow * Set low phi limit (with unit, def: degree).
	   phihigh * Set high phi limit (with unit, def: degree).
	   t0 * Set initial t0 of the particle (with unit, def: ns).
	   polarization * Set polarization.
	   number * Set number of particles to be generated.

	- NTSTBabarEvtReadGenerator ('evt'):
	reads an ascii file of events which have been generated previously by
	GenFwkInt, the BaBar generator framework interface. A file,
	babarevt.out, contains 1000 B-Bbar events generated at the Upsilon 4S
	and boosted into the BaBar detector rest frame (recall that in this
	frame, the e- and e+ beams collide with momenta of +9 and -3.1 GeV,
	respectively. The beam axis is rotated by -20.5mr from the z-axis in
	the x-z plane and the interaction point is sampled from a beam
	spot of approximately 100 microns (x), 4.6 microns (y) and 1 cm (z)).
	There is no messenger associated with this generator.
 	
 	A RUN is a set of events.
 	
 3- PHYSICS PROCESSES

	The physics processes are set in a class called NTSTPhysicsList. 
	There is a messenger which controls the settings of some of the 
	processes. The commands available to the user are listed in /run:

	 Sub-directories : 
	   /run/particle/   Commands for G4VUserPhysicsList.
	 Commands : 
	   initialize * Initialize G4 kernel.
	   beamOn * Start a Run.
	   verbose * Set the Verbose level of G4RunManager.
	   optimizeGeometry * Set the optimization flag for geometry.
	   breakAtBeginOfEvent * Set a break point at the begining of every event.
	   breakAtEndOfEvent * Set a break point at the end of every event.
	   abort * Abort current run processing.
	   geometryModified * Force geometry to be closed again.
	   cutoffModified * Force closssection tables to be calculated again.
	   storeRandomNumberStatus * Store the status of the random number engine to a file.
	   restoreRandomNumberStatus * Restore the status of the random number engine from a file.
	   setEmProcess * select electromagnetic processes
	   useBgsTran * True if BgsTransportation to be used
	   minEcut * ParticleWithCuts minimum energy cut (with unit, def: MeV)
	   maxEcut * ParticleWithCuts maximum energy cut (with unit, def: MeV)
	   cut * new cut value (with unit, def: mm)
	   looperCut * Kill loopers below this cut (with unit, def: MeV)

 3- DETECTOR RESPONSE
	No hits/digis are currently scored.
 
 4- VISUALIZATION
 	
 6- HOW TO START ?
 
 	- compile and link to generate an executable
 		% cd NTST
 		% gmake
 		
 	- execute NTST in 'interactive mode' with visualization
		% exampleNTST
 		% exampleNTST
 		....
 		Idle> type your commands
 		....
 		Idle> exit
	- or use the supplied macro files:

file    	Transportation	 range cut	looper cut	e-cut
---------------------------------------------------------------------------
run2a.mac	G4Transportation 2 mm		< 200 MeV	< 1 MeV
run2b.mac		"	 2 mm 		< 200 MeV	not applied
run2c.mac		"	 2 mm		not applied	not applied
---------------------------------------------------------------------------
		% exampleNTST run2c.mac will run G4 using G4Transportation
					with the default range/energy cuts
					using the 'evt' generator.