171 lines
6.1 KiB
Plaintext
171 lines
6.1 KiB
Plaintext
$Id: README,v 1.22 2007/11/12 15:48:58 maire Exp $
|
|
-------------------------------------------------------------------
|
|
|
|
=========================================================
|
|
Geant4 - an Object-Oriented Toolkit for Simulation in HEP
|
|
=========================================================
|
|
|
|
TestEm1
|
|
-------
|
|
How to count processes.
|
|
How to activate/inactivate processes.
|
|
How to survey the tracking, in perticular the range of charged particles.
|
|
How to define a maximum step size.
|
|
|
|
1 - GEOMETRY DEFINITION
|
|
|
|
It is a simple box which represente an 'semi 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 for gamma and 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.
|
|
|
|
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, 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 - TRACKING : StepMax
|
|
|
|
In order to control the accuracy of the deposition, the user can limit
|
|
'by hand' the maximum step size of charged particles.
|
|
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.
|
|
|
|
8 - HISTOGRAMS
|
|
|
|
Testem1 produces several histo which are saved as testem1.hbook by default.
|
|
Content of these histo:
|
|
1 : track length of primary particle
|
|
2 : number of steps primary particle
|
|
3 : step size of primary particle
|
|
|
|
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 testem1)
|
|
|
|
It is possible to choose the format of the histogram file (hbook, root, XML)
|
|
with the command /testem/histo/setFileType (hbook by default)
|
|
|
|
It is also possible to print selected histograms on an ascii file:
|
|
/testem/histo/printHisto id
|
|
All selected histos will be written on a file name.ascii (default testem1)
|
|
|
|
Note that, by default, histograms are disabled. To activate them, uncomment
|
|
the flag G4ANALYSIS_USE in GNUmakefile.
|
|
|
|
Before compilation of the example it is optimal to clean up old files:
|
|
gmake histclean
|
|
gmake
|
|
|
|
9 - USING HISTOGRAMS
|
|
|
|
To use histograms, at least one of the AIDA implementations should be
|
|
available (see http://aida.freehep.org).
|
|
|
|
9a - 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`
|
|
|
|
9b - 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
|