source: trunk/examples/extended/hadronic/Hadr01/README@ 1342

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     Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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                                 HADR01

            A.Bagulya, I.Gudowska, V.Ivanchenko, N.Starkov
                       CERN, Geneva, Switzerland
            Karolinska Institute & Hospital, Stockholm, Sweden
               Lebedev Physical Institute, Moscow, Russia


This example application is based on the application IION developed for
simulation of proton or ion beam interaction with a water target. Different 
aspects of beam target interaction are demonstrating in the example including 
longitudinal profile of energy deposition, spectra of secondary  particles,
spectra of particles leaving the target. The results are presenting in a form
of average numbers and histograms. 


                           GEOMETRY

The Target volume is a cylinder placed inside Check cylindrical volume. The 
Check volume is placed inside the World volume. The radius and the length of
the Check volume are 1 mm larger than the radius and the length of the Target.
The material of the Check volume is the same as the World material.  The World
volume has the sizes 10 mm larger than that of the Target volume.  Any material
from the Geant4 database can be defined. The default World  material is
G4Galactic and the default  Target material is aluminum. The Target is
subdivided on number of equal slices. Following UI commands are available to
modify the geometry:

/testhadr/TargetMat     G4_Pb
/testhadr/WorldMat      G4_AIR
/testhadr/TargetRadius  10 mm
/testhadr/TargetLength  20 cm
/testhadr/NumberDivZ    200

If geometry was changed between two runs, then the following command need to
be executed:

/testhadr/Update

Beam direction coincides with the target axis and is Z axis in the global
coordinate system. The beam starts 5 mm in front of the target. G4ParticleGun
is used as a primary generator. The energy and the type of the beam can be
defined via standard UI commands

/gun/energy   15 GeV
/gun/particle proton

Default beam position is -(targetHalfLength + 5*mm) and direction along Z axis.
Beam position and direction can be changed by gun UI commands:

/gun/position  1 10 3 mm
/gun/direction 1 0 0

however, position command is active only if before it the flag is set

/testhadr/DefaultBeamPosition false   
 
                           SCORING

The scoring is performed with the help of UserStackingAction class and two
sensitive detector  classes: one associated with a target slice, another with
the Check volume. Each secondary particle is scored by the StackingAction.  In
the StackingAction it is also possible to kill all or one type of secondary 
particles 

/testhadr/Kill             neutron
/testhadr/KillAllSecondaries  

To control running the following options are available:

/testhadr/PrintModulo      100
/testhadr/DebugEvent       977

The last command selects an events, for which "/tracking/verbose 2" level
of printout is established.


                           PHYSICS

PhysicsList of the application uses components, which are distributed with
Geant4 in /geant4/physics_lists subdirectory. 

There is a possibility directly use one of reference Physics Lists if 
using the environment variable PHYSLIST. Alternatively the name of the reference
Physics List can be given via parameter of the the application as following:

$G4BIN/Linux++/hadr01 QGSP_BERT my.macro

Finally it is possible to use UI commands (PHYSLIST environment variable is not 
defined). The choice of the physics is provided by the UI command:

/testhadr/Physics     QGSP_BIC

To see the list of available configurations with UI one can use

/testhadr/ListPhysics

The cuts for electromagnetic physics can be established via

/testhadr/CutsAll       1 mm
/testhadr/CutsGamma   0.1 mm
/testhadr/CutsEl      0.2 mm
/testhadr/CutsPos     0.3 mm

Note that testhadr UI commands are not available in the case when PHYSLIST 
environment variable is defined. 


                          VISUALIZATION

For interactive mode G4 visualization options and variables should be
defined, then the example should be recompiled:

gmake visclean
gmake

The vis.mac file can be used an example of visualization. The following command can 
be used:

/testhadr/DrawTracks  charged
/testhadr/DrawTracks  charged+n
/testhadr/DrawTracks  neutral
/testhadr/DrawTracks  all


                          HISTOGRAMS

To use histograms any of implementations of AIDA interfaces should
be available (see http://aida.freehep.org).

A package including AIDA and extended interfaces also using Python
is PI, available from: http://cern.ch/pi .

Once installed PI or PI-Lite in a specified local area $PI_DIR, it is
required to add the installation path to $PATH, i.e. for example,
for release 1.2.1 of PI:

setenv PATH ${PATH}:$PI_DIR/1.3.12/app/releases/PI/PI_1_3_12/slc3_gcc323/bin

CERN users can use the PATH to the LCG area on AFS.

Before compilation of the example it is optimal to clean up old 
files:

gmake histclean
setenv G4ANALYSIS_USE 1
gmake

Before running the example the command should be issued:

eval `aida-config --runtime csh`

It is possible to choose the format of the output file with 
histograms using UI command:

/testhadr/HistoName   name
/testhadr/HistoType   type
/testhadr/HistoOption "uncompress"

The following types are available: hbook, root, aida. They will be 
stored in the file "name.hbook", "name.root", or "name.aida". 
If the environment variable HISTODIR is defined, files are stored in this 
subdirectory.

To show the content of a histogram ID=i the commands may be applied:

/testhadr/HistoPrint  i

All histograms are normalized to the number of events.