Gabriele Cosmo
140 lines
4.4 KiB
Plaintext
140 lines
4.4 KiB
Plaintext
$Id: README,v 1.12 2004/06/23 11:31:00 maire Exp $
|
|
-------------------------------------------------------------------
|
|
|
|
=========================================================
|
|
Geant4 - an Object-Oriented Toolkit for Simulation in HEP
|
|
=========================================================
|
|
|
|
TestEm1
|
|
-------
|
|
|
|
This example has been setup to test individualy the electromagnetic
|
|
processes.
|
|
|
|
1- GEOMETRY DEFINITION
|
|
|
|
It is a simple box which represente an 'infinite' homogeneous medium.
|
|
|
|
Two parameters define the geometry :
|
|
- the material of the box,
|
|
- the (full) size of the box.
|
|
|
|
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/exampleN03.
|
|
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+, proton or directly in energy for all charged.
|
|
|
|
3- AN EVENT : THE PRIMARY GENERATOR
|
|
|
|
The primary kinematic consists of a single particle starting at the
|
|
middle 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- PHYSICS SURVEY
|
|
|
|
The particle's type and the physic processes which will be available
|
|
in this example are set in PhysicsList class.
|
|
|
|
A set of macros defining various run conditions are provided.
|
|
The processes are actived/inactived together with differents
|
|
cuts, in order to survey the processes one by one.
|
|
|
|
The number of produced secondaries are counted, the number of steps,
|
|
and the number of process calls responsible of the step.
|
|
|
|
6- HOW TO START ?
|
|
|
|
- compile and link to generate an executable
|
|
% cd geant4/examples/extended/electromagnetic/TestEm1
|
|
% gmake
|
|
|
|
- execute TestEm1 in 'batch' mode from macro files
|
|
% TestEm1 run10.mac
|
|
|
|
- execute TestEm1 in 'interactive mode' with visualization
|
|
% TestEm1
|
|
....
|
|
Idle> type your commands
|
|
....
|
|
Idle> exit
|
|
|
|
7- HISTOGRAMS
|
|
|
|
Testem1 produces several histo which are saved as testem1.paw
|
|
|
|
Content of these histo:
|
|
|
|
1 : track length of a charged particle
|
|
2 : number of steps per track (charged particle)
|
|
3 : step length (charged particle)
|
|
|
|
Note that, by default, histograms are disabled. To activate them, uncomment
|
|
the flag G4ANALYSIS_USE in GNUmakefile.
|
|
|
|
|
|
8- Using histograms
|
|
-------------------
|
|
|
|
By default the histograms are not activated. To activate histograms
|
|
the environment variable G4ANALYSIS_USE should be defined. For instance
|
|
uncomment the flag G4ANALYSIS_USE in GNUmakefile.
|
|
|
|
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 $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 compilation of the example it is optimal to clean up old
|
|
files:
|
|
|
|
gmake histclean
|
|
gmake
|
|
|
|
Before running the example the command should be issued:
|
|
|
|
eval `aida-config --runtime csh`
|
|
|