$Id: README,v 1.7 2007/11/09 17:35:06 maire Exp $ ------------------------------------------------------------------- ========================================================= Geant4 - an Object-Oriented Toolkit for Simulation in HEP ========================================================= TestEm12 -------- How to plot a depth dose profile in spherical geometry. 1- GEOMETRY DEFINITION The geometry consists of a single sphere of an homogenous material. Optionally, the sphere can be divided in thin shells. 3 parameters define the geometry : - the material of the sphere, - the radius of the sphere (absorRadius), - the number of shells (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 randomly shooted at the centre of the sphere. 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 desactivate the randomness of the direction 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 TestEm12 in 'batch' mode from macro files % TestEm12 run01.mac - execute TestEm12 in 'interactive mode' with visualization % TestEm12 .... Idle> type your commands .... Idle> exit 6- TRACKING and STEP MAX Testem12 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 histograms 1 and 8 (see HistoManager). 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 Testem12 has several predefined 1D histograms : 1 : energy profile dE/dr (in MeV/mm 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 8 : normalized energy profile d(E/E0)/d(r/r0), where r0 is the range of the primary particle of energy E0 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 testem12) 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 testem12) 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 </aida-setup.csh or with a sh flavoured shell : sh> . </aida-setup.sh On Windows : DOS> call </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