$Id: README,v 1.7 2002/12/12 13:26:50 maire Exp $ ------------------------------------------------------------------- ========================================================= Geant4 - an Object-Oriented Toolkit for Simulation in HEP ========================================================= TestEm5 ------- 1- GEOMETRY DEFINITION The "absorber" is a box made of a given material. Three parameters define the absorber : - the material of the absorber, - the thickness of an absorber, - the transverse size of the absorber (the input face is a square). The volume "World" contains the "absorber". In this test the parameters of the "World" can be changed, too. In addition a transverse uniform magnetic field can be applied. The default geometry is constructed in DetectorConstruction class, but all the parameters can be changed via the commands defined in the DetectorMessenger class. 2- AN EVENT : THE PRIMARY GENERATOR The primary kinematic consists of a single particle which hits the absorber perpendicular to the input face. 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. 3- DETECTOR RESPONSE A HIT is a record, event per event , of all the informations needed to simulate and analyse the detector response. In this example a CalorHit is defined as a set of 2 informations: - the total energy deposit in the absorber, - the total tracklength of all charged particles in the absorber, Therefore the absorber is declared 'sensitive detector' (SD), which means they can contribute to the hit. At the end of a run, from the histogram(s), one can study different physics quantities such as : - angle distribution, - energy deposit, - transmission/backscattering, - ... The test contains 10 built-in histograms, which can be activated by interactive commands (see the macros runxx.mac for details). The histograms/plots are in printed form in the corresponding resultxx (for GEANT4) and outxx (for GEANT3) files, and they are saved as geant4.plotxx and geant3.plotxx histogram files, too. The histogram files can be viewed using PAW e.g with the commands paw> h/file 1 geant4.plot01 paw> option stat paw> h/pl 1 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. In interactive session: PreInit or Idle > /control/execute vis.mac The detector has a default view which is a longitudinal view of the calorimeter. 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 DEMO The particle's type and the physic processes which will be available in this example are set in PhysicsList class. The messenger classes introduce interactive commands . Using these commands the geometry of the detector, the data of the primary particle, the limits of the histograms , etc. can be changed. 6- HOW TO START ? - compile and link to generate an executable % cd TestEm5 % gmake - execute TestEm5 in 'batch' mode from macro files e.g. % $(G4INSTALL)/bin/$(G4SYSTEM)/TestEm5 run01.mac - execute TestEm5 in 'interactive' mode with visualization e.g. % $(G4INSTALL)/bin/$(G4SYSTEM)/TestEm5 .... Idle> type your commands .... 7- GEANT4/GEANT3/exp.data comparison A GEANT4/GEANT3/exp. data comparison is given here for a few cases. The GEANT4 results can be found in the results/ directory, the resultxx output was obtained with the runxx.mac macro. The relevant part of the GEANT3 code is in the geant3/ directory together with the runxx.dat input files. The outputs of the GEANT3 runs geant3/results subdirectory. In order to make an executable of GEANT3 the gmakeB command should be used in the geant3/ subdirectory.To run this executable with a given input file the input file name should be given when it is being asked by the program.(see geant3/README) The expdata/ directory contains some information on the experimental data. List of the built-in histograms ------------------------------- 1. number of (tracking) steps/event 2. energy deposit distribution in the absorber (in MeV) 3. angle distribution of the primary particle at the exit of the absorber (deg) 4. distribution of the lateral displacement at exit(mm) 5. kinetic energy of the transmitted primaries (MeV) 6. angle distribution of the backscattered primaries (deg) 7. kinetic energy of the backscattered primary particles (MeV) 8. kinetic energy of the charged secondary particles (MeV) 9. z distribution of the secondary charged vertices (mm) 10. kinetic energy of the photons escaping the absorber (MeV) Note that histograms are disabled via the flag G4NOHIST in GNUmakefile. 8- Using the Anaphe implementation of the AIDA 3.0 histograms: -------------------------------------------------------------- In order to use the Anaphe implementation of the AIDA 3.0 interfaces, the 'aida-config' command (which is used in the GNUmakefile) is available at: /afs/cern.ch/sw/lhcxx/share/LHCXX/latest/scripts/aida-config In order to run the executable, you need to source the following script (once): $HOME/bin/setupAnaphe.csh (or $HOME/bin/setupAnaphe) At cern 'setupAnaphe' is available at: /afs/cern.ch/sw/lhcxx/share/LHCXX/latest/scripts/setupAnaphe.csh (or /afs/cern.ch/sw/lhcxx/share/LHCXX/latest/scripts/setupAnaphe)