Gabriele Cosmo
144 lines
4.7 KiB
Plaintext
144 lines
4.7 KiB
Plaintext
$Id: README,v 1.3 2004/06/23 11:28:26 maire Exp $
|
|
-------------------------------------------------------------------
|
|
|
|
=========================================================
|
|
Geant4 - an Object-Oriented Toolkit for Simulation in HEP
|
|
=========================================================
|
|
|
|
PhotonProcesses
|
|
---------------
|
|
|
|
This test is devoted to the photon processes: gamma conversion, coherent
|
|
and incoherent scattering, photoelectric effect. It allows to compute
|
|
absorption coefficients and to plot final state.
|
|
|
|
1- GEOMETRY DEFINITION
|
|
|
|
It is a single box representing a 'semi infinite' homogeneous medium.
|
|
Two parameters define the geometry :
|
|
- the material of the box,
|
|
- the (full) size of the box.
|
|
|
|
The default geometry (100 m of water) is constructed in
|
|
DetectorConstruction, but the above parameters can be changed
|
|
interactively via the commands defined in DetectorMessenger.
|
|
|
|
2- PHYSICS LIST
|
|
|
|
The particle list contains only gamma, e+, e-, mu+, mu-.
|
|
The physics list contains the 'standard' electromagnetic processes.
|
|
|
|
3- AN EVENT : THE PRIMARY GENERATOR
|
|
|
|
The primary kinematic consists of a single particle starting at the edge
|
|
of the box. The type of the particle and its energy are set in
|
|
PrimaryGeneratorAction (1 MeV gamma), and can be changed via the G4
|
|
build-in commands of ParticleGun class (see the macros provided with
|
|
this example).
|
|
|
|
4- PHYSICS
|
|
|
|
The incident particle is a photon. The event is killed at the first
|
|
interaction of the photon.
|
|
The absorption length is computed as the mean value of the track length
|
|
of the photon.
|
|
The energy spectrum and the angular distribution of the scattered photon
|
|
(if any) and of the secondaries are plotted (see SteppingAction).
|
|
|
|
A set of macros defining various run conditions are provided.
|
|
The processes are actived/inactived in order to survey the processes
|
|
individually.
|
|
|
|
5- HISTOGRAMS
|
|
|
|
The test contains 6 built-in 1D histograms, which 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, etc..)
|
|
(see the macros xxxx.mac).
|
|
|
|
1 "scattered primary particle: energy spectrum"
|
|
2 "scattered primary particle: costheta distribution"
|
|
3 "charged secondaries: energy spectrum"
|
|
4 "charged secondaries: costheta distribution"
|
|
5 "neutral secondaries: energy spectrum"
|
|
6 "neutral secondaries: costheta distribution"
|
|
|
|
The histograms can be viewed using PAW. See below the note on
|
|
ANAPHE+AIDA.
|
|
|
|
One can control the name of the histograms file with the command:
|
|
/testem/histo/setFileName name (default photonprocesses.paw)
|
|
|
|
Note that, by default, histograms are disabled. To activate them,
|
|
uncomment the flag G4ANALYSIS_USE in GNUmakefile.
|
|
|
|
6- 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.
|
|
|
|
7- HOW TO START ?
|
|
|
|
compile and link to generate an executable
|
|
% cd geant4/examples/extended/electromagnetic/PhotonProcesses
|
|
% gmake
|
|
|
|
execute PhotonProcesses in 'batch' mode from macro files :
|
|
% PhotonProcesses compt.mac
|
|
|
|
execute PhotonProcesses in 'interactive mode' with visualization :
|
|
% PhotonProcesses
|
|
Idle> control/execute vis.mac
|
|
....
|
|
Idle> type your commands
|
|
....
|
|
Idle> exit
|
|
|
|
|
|
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`
|
|
|
|
It is possible to choose the format of the output file with
|
|
histograms using UI command:
|
|
|
|
/testem/histo/setFileType type
|
|
|
|
The following types are available: hbook, root, xml.
|