$Id: README,v 1.5 2006/05/15 14:41:29 maire Exp $
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Geant4 - an Object-Oriented Toolkit for Simulation in HEP
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TestEm11
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How to plot a depth dose profile in a rectangular box.
1- GEOMETRY DEFINITION
The geometry consists of a single block of an homogenous material.
Optionally, the block can be divided in thinner layers (replica)
4 parameters define the geometry :
- the material of the box,
- the thickness of the box (sizeX),
- the tranverse dimension of the box (sizeYZ).
- the number of layers (nbOfLayers)
In addition a transverse uniform magnetic field can be applied.
The default geometry is constructed in DetectorConstruction class,
but all of the above parameters can be changed interactively via
the commands defined in the DetectorMessenger class.
2- PHYSICS LIST
The particle list is the one of novice/exampleN02.
The physics list contains the 'standard' electromagnetic processes,
and decay.
Few commands have been added to PhysicsList, in order to set the
production threshold for secondaries either in range for gamma, e-/e+.
3- AN EVENT : THE PRIMARY GENERATOR
The primary kinematic consists of a single particle starting at the
left face of the box. The type of the particle and its energy are set
in the PrimaryGeneratorAction class, and can be changed via the G4
build-in commands of ParticleGun class (see the macros provided with
this example).
In addition one can choose randomly the impact point of the incident
particle. The corresponding interactive command is built in
PrimaryGeneratorMessenger class.
A RUN is a set of events.
4- VISUALIZATION
The Visualization Manager is set in the main().
The initialisation of the drawing is done via the commands
/vis/... in the macro vis.mac. To get visualisation:
> /control/execute vis.mac
The detector has a default view which is a longitudinal view of the
box.
The tracks are drawn at the end of event, and erased at the end of run.
Optionaly one can choose to draw all particles, only the charged one,
or none. This command is defined in EventActionMessenger class.
5- HOW TO START ?
- compile and link to generate an executable
% cd geant4/examples/extended/electromagnetic/TestEm1
% gmake
- execute TestEm11 in 'batch' mode from macro files
% TestEm11 run01.mac
- execute TestEm11 in 'interactive mode' with visualization
% TestEm11
....
Idle> type your commands
....
Idle> exit
6- TRACKING and STEP MAX
Testem11 computes the total energy deposited along the trajectory of
the incident particle : the so-called longitudinal energy profile,
or depth dose distribution.
The energy deposited (edep) is randomly distribued along the step (see
SteppingAction).
In order to control the accuracy of the deposition, the maximum step size
of charged particles is computed automatically from the binning of
histogram 1.
As an example, this limitation is implemented as a 'full' process :
see StepMax class and its Messenger. The 'StepMax process' is registered
in the Physics List.
In RunAction::BeginOfRun() the stepMax value is passed from the
HistoManager to the StepMax process.
A boolean UI command allows to desactivate this mechanism.
7- HISTOGRAMS
Testem11 has several predefined 1D histograms :
1 : longitudinal energy profile (in MeV/mm and per event)
2 : total energy deposited in the absorber
3 : total track length of the primary track
4 : step size of the primary track
5 : projected range of the primary track
6 : total track length of charged secondary tracks
7 : step size of charged secondary tracks
The histograms are managed by the HistoManager class and its Messenger.
The histos can be individually activated with the command :
/testem/histo/setHisto id nbBins valMin valMax unit
where unit is the desired unit for the histo (MeV or keV, deg or mrad, etc..)
One can control the name of the histograms file with the command:
/testem/histo/setFileName name (default testem11)
It is possible to choose the format of the histogram file (hbook, root, XML)
with the command /testem/histo/setFileType (hbook by default)
Note that, by default, histograms are disabled. To activate them, uncomment
the flag G4ANALYSIS_USE in GNUmakefile.
8- USING HISTOGRAMS
To use histograms, at least one of the AIDA implementations should be
available (see http://aida.freehep.org).
8a - PI
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 $MYPY, it is required
to add the installation path to $PATH, i.e. for example, for release 1.2.1 of
PI:
setenv PATH ${PATH}:$MYPI/1.2.1/app/releases/PI/PI_1_2_1/rh73_gcc32/bin
CERN users can use the PATH to the LCG area on AFS.
Before running the example the command should be issued:
eval `aida-config --runtime csh`
8b - OpenScientist
OpenScientist is available at http://OpenScientist.lal.in2p3.fr.
You have to "setup" the OpenScientist AIDA implementation before compiling
(then with G4ANALYSIS_USE set) and running your Geant4 application.
On UNIX you setup, with a csh flavoured shell :
csh> source <<OpenScientist install path>/aida-setup.csh
or with a sh flavoured shell :
sh> . <<OpenScientist install path>/aida-setup.sh
On Windows :
DOS> call <<OpenScientist install path>/aida-setup.bat
You can use various file formats for writing (AIDA-XML, hbook, root).
These formats are readable by the Lab onx interactive program
or the OpenPAW application. See the web pages.
With OpenPAW, on a run.hbook file, one can view the histograms
with something like :
OS> opaw
opaw> h/file 1 run.hbook ( or opaw> h/file 1 run.aida or run.root)
opaw> zone 2 2
opaw> h/plot 1
opaw> h/plot 2
Gabriele Cosmo