[807] | 1 | |
---|
| 2 | ========================================================= |
---|
| 3 | Geant4 - an Object-Oriented Toolkit for Simulation in HEP |
---|
| 4 | ========================================================= |
---|
| 5 | |
---|
| 6 | lArCal |
---|
| 7 | -------- |
---|
| 8 | |
---|
| 9 | This example is intended to simulate the Forward Liquid Argon Calorimeter |
---|
| 10 | (FCAL) of the ATLAS Detector at LHC. The goal of the FCAL is to provide |
---|
| 11 | a good missing energy determination in the region of very small angles |
---|
| 12 | from the beam direction. |
---|
| 13 | |
---|
| 14 | |
---|
| 15 | 1. GEOMETRY DEFINITION |
---|
| 16 | ------------------------ |
---|
| 17 | |
---|
| 18 | The liquid Argon calorimeter consists of three modules with the same |
---|
| 19 | nominal outer dimensions: an electromagnetic module (made |
---|
| 20 | of copper) followed by two hadronic ones (made of tungsten alloy). |
---|
| 21 | The corresponding parameters of these modules are defined inside the |
---|
| 22 | FCALEMModuleParameters.input and FCALHadModuleParameters.input files. |
---|
| 23 | The package contains as well a FCALTestbemSetup class whose geometry is given by |
---|
| 24 | FCALTestbeamSetupParameters.input. See these files for details concerning to |
---|
| 25 | radius, lenght and angles of the different components. |
---|
| 26 | |
---|
| 27 | |
---|
| 28 | 2. AN EVENT : THE PRIMARY GENERATOR |
---|
| 29 | ------------------------------------ |
---|
| 30 | |
---|
| 31 | The primary kinematic consists of a single particle which hits the |
---|
| 32 | geometry perpendicular to the input face. The FCALPrimaryGeneratorAction |
---|
| 33 | class gives the particle and its energy (by default it is an electron of |
---|
| 34 | 80 GeV). These parameters can be changed in commands of ParticleGun class |
---|
| 35 | inside the macros given in this example. |
---|
| 36 | |
---|
| 37 | The subdirectory data-tracks contains the kinematic files |
---|
| 38 | of the particles for different energies (20 GeV, 40 GeV, 60 GeV, 80 GeV, |
---|
| 39 | 120 GeV and 200 GeV). |
---|
| 40 | The information given inside these files are the X, Y, Z and cosX, |
---|
| 41 | cosY, cosZ variables for each event. |
---|
| 42 | |
---|
| 43 | A RUN is a set of events. |
---|
| 44 | |
---|
| 45 | |
---|
| 46 | 3. VISUALIZATION |
---|
| 47 | ------------------ |
---|
| 48 | |
---|
| 49 | The Visualization Manager is set in the main(). |
---|
| 50 | The initialisation of the drawing is done via the command |
---|
| 51 | > /control/execute vis.mac |
---|
| 52 | |
---|
| 53 | The detector has a default view which is a transversal view of the geometry. |
---|
| 54 | |
---|
| 55 | The tracks are drawn at the end of event, and erased at the end of run. |
---|
| 56 | Optionally the way of drawing the particles can be changed in the |
---|
| 57 | TBEVentActionMessenger class. |
---|
| 58 | |
---|
| 59 | |
---|
| 60 | 4. PHYSICS |
---|
| 61 | ---------- |
---|
| 62 | |
---|
| 63 | You can select between 3 Physics Lists: QGSP (default), LHEP, QGSC. |
---|
| 64 | The selection is done simply by comment/uncomment a line in the main |
---|
| 65 | lArCal.cc (look for the keyword ***LOOKHERE***). |
---|
| 66 | |
---|
| 67 | |
---|
| 68 | 5. HOW TO START ? |
---|
| 69 | ----------------- |
---|
| 70 | |
---|
| 71 | - compile and link to generate an executable |
---|
| 72 | % cd geant4/examples/advanced/lAr_calorimeter |
---|
| 73 | % gmake |
---|
| 74 | |
---|
| 75 | - execute the program in 'batch' mode from macro files |
---|
| 76 | % lArCal prerunlArcal.mac |
---|
| 77 | |
---|
| 78 | - execute Test in 'interactive mode' with visualization |
---|
| 79 | % lArCal |
---|
| 80 | ... |
---|
| 81 | Idle> type your commands |
---|
| 82 | ... |
---|
| 83 | Idle> exit |
---|
| 84 | |
---|
| 85 | |
---|
| 86 | 6. HISTOGRAMS |
---|
| 87 | -------------- |
---|
| 88 | |
---|
| 89 | lArCal produces 4 histograms (saved as fcal.his) which illustrate |
---|
| 90 | the final state of the most important variables of the example: |
---|
| 91 | |
---|
| 92 | Histo1 --> Number of tracks out of World |
---|
| 93 | Histo2 --> Number of secondary particles |
---|
| 94 | Histo3 --> Total energy deposited (in MeV) in the electromagnetic module |
---|
| 95 | Histo4 --> Total energy deposited (in MeV) in the hadronic module |
---|
| 96 | |
---|
| 97 | See their definitions in FCALAnalysisManager.cc |
---|
| 98 | |
---|
| 99 | Note that histograms are disabled via the flag G4ANALYSIS_USE in GNUmakefile. |
---|
| 100 | |
---|
| 101 | |
---|
| 102 | 7. Using the PI implementation of the AIDA histograms: |
---|
| 103 | ------------------------------------------------------ |
---|
| 104 | |
---|
| 105 | In order to setup the proper environmental variables, needed for |
---|
| 106 | running AIDA / PI , run the script: |
---|
| 107 | |
---|
| 108 | --- For c-shell : source setupAidaPi.csh |
---|
| 109 | |
---|
| 110 | --- For bash-shell : . setupAidaPi.sh |
---|
| 111 | |
---|
| 112 | Notice that you need g++ 3.2 or 3.23. |
---|
| 113 | |
---|
| 114 | |
---|