| Geant4 Cross Reference |
1 1
2 ========================================= 2 =========================================================
3 Geant4 - an Object-Oriented Toolkit for S 3 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
4 ========================================= 4 =========================================================
5 5
6 lArCal 6 lArCal
7 -------- 7 --------
8 8
9 This example is intended to simulate the Forw 9 This example is intended to simulate the Forward Liquid Argon Calorimeter
10 (FCAL) of the ATLAS Detector at LHC. The goal 10 (FCAL) of the ATLAS Detector at LHC. The goal of the FCAL is to provide
11 a good missing energy determination in the re 11 a good missing energy determination in the region of very small angles
12 from the beam direction. 12 from the beam direction.
13 13
14 14
15 1. GEOMETRY DEFINITION 15 1. GEOMETRY DEFINITION
16 ------------------------ 16 ------------------------
17 17
18 The liquid Argon calorimeter consists of thre 18 The liquid Argon calorimeter consists of three modules with the same
19 nominal outer dimensions: an electromagnetic 19 nominal outer dimensions: an electromagnetic module (made
20 of copper) followed by two hadronic ones (mad 20 of copper) followed by two hadronic ones (made of tungsten alloy).
21 The corresponding parameters of these modules 21 The corresponding parameters of these modules are defined inside the
22 FCALEMModuleParameters.input and FCALHadModul 22 FCALEMModuleParameters.input and FCALHadModuleParameters.input files.
23 The package contains as well a FCALTestbemSet 23 The package contains as well a FCALTestbemSetup class whose geometry is given by
24 FCALTestbeamSetupParameters.input. See these 24 FCALTestbeamSetupParameters.input. See these files for details concerning to
25 radius, lenght and angles of the different co 25 radius, lenght and angles of the different components.
26 26
27 27
28 2. AN EVENT : THE PRIMARY GENERATOR 28 2. AN EVENT : THE PRIMARY GENERATOR
29 ------------------------------------ 29 ------------------------------------
30 30
31 The primary kinematic consists of a single pa 31 The primary kinematic consists of a single particle which hits the
32 geometry perpendicular to the input face. The 32 geometry perpendicular to the input face. The FCALPrimaryGeneratorAction
33 class gives the particle and its energy (by d 33 class gives the particle and its energy (by default it is an electron of
34 20 GeV). These parameters can be changed in c 34 20 GeV). These parameters can be changed in commands of ParticleGun class
35 inside the macros given in this example. 35 inside the macros given in this example.
36 36
37 The subdirectory data-tracks contains the kin 37 The subdirectory data-tracks contains the kinematic files
38 of the particles for different energies (20 G 38 of the particles for different energies (20 GeV, 40 GeV, 60 GeV, 80 GeV,
39 120 GeV and 200 GeV). 39 120 GeV and 200 GeV).
40 The information given inside these files are 40 The information given inside these files are the X, Y, Z and cosX,
41 cosY, cosZ variables for each event. 41 cosY, cosZ variables for each event.
42 42
43 A RUN is a set of events. 43 A RUN is a set of events.
44 44
45 45
46 3. VISUALIZATION 46 3. VISUALIZATION
47 ------------------ 47 ------------------
48 48
49 The Visualization Manager is set in the main( 49 The Visualization Manager is set in the main().
50 The initialisation of the drawing is done via 50 The initialisation of the drawing is done via the command
51 > /control/execute vis.mac 51 > /control/execute vis.mac
52 52
53 The detector has a default view which is a tr 53 The detector has a default view which is a transversal view of the geometry.
54 54
55 The tracks are drawn at the end of event, and 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 c 56 Optionally the way of drawing the particles can be changed in the
57 TBEVentActionMessenger class. 57 TBEVentActionMessenger class.
58 58
59 59
60 4. PHYSICS 60 4. PHYSICS
61 ---------- 61 ----------
62 62
63 You can select between 4 Physics Lists: QGSP, 63 You can select between 4 Physics Lists: QGSP, LHEP, QGSC, QGSP_BIC_EMY.
64 The last one is set as default, so that you c 64 The last one is set as default, so that you can test the low-energy
65 electromagnetic. 65 electromagnetic.
66 The selection is done simply by comment/uncom 66 The selection is done simply by comment/uncomment a line in the main
67 lArCal.cc (look for the keyword ***LOOKHERE 67 lArCal.cc (look for the keyword ***LOOKHERE***).
68 68
69 69
70 5. HOW TO START ? 70 5. HOW TO START ?
71 ----------------- 71 -----------------
72 72
73 - compile and link to generate an executable 73 - compile and link to generate an executable
74 % cd geant4/examples/advanced/lAr_calori 74 % cd geant4/examples/advanced/lAr_calorimeter
75 % gmake 75 % gmake
76 76
77 - execute the program in 'batch' mode from m 77 - execute the program in 'batch' mode from macro files
78 % lArCal prerunlArcal.mac 78 % lArCal prerunlArcal.mac
79 79
80 - execute Test in 'interactive mode' with vi 80 - execute Test in 'interactive mode' with visualization
81 % lArCal 81 % lArCal
82 ... 82 ...
83 Idle> type your commands 83 Idle> type your commands
84 ... 84 ...
85 Idle> exit 85 Idle> exit
86 86
87 87
88 6. HISTOGRAMS 88 6. HISTOGRAMS
89 -------------- 89 --------------
90 The analysis is performed using the histogram 90 The analysis is performed using the histogramming tools provided by
91 Geant4. No external dependencies are required 91 Geant4. No external dependencies are required.
92 92
93 lArCal produces 4 histograms (saved as fcal.r 93 lArCal produces 4 histograms (saved as fcal.root) which illustrate
94 the final state of the most important variabl 94 the final state of the most important variables of the example:
95 95
96 Histo1 --> Number of tracks out of World 96 Histo1 --> Number of tracks out of World
97 Histo2 --> Number of secondary particles 97 Histo2 --> Number of secondary particles
98 Histo3 --> Total energy deposited (in MeV) in 98 Histo3 --> Total energy deposited (in MeV) in the electromagnetic module
99 Histo4 --> Total energy deposited (in MeV) in 99 Histo4 --> Total energy deposited (in MeV) in the hadronic module
100 100
101 See their definitions in FCALRunAction.cc 101 See their definitions in FCALRunAction.cc
102 102
103 The histograms are saved (default) as a ROOT 103 The histograms are saved (default) as a ROOT file. It is possible to save the
104 histograms in a xml file by changing the G4An 104 histograms in a xml file by changing the G4AnalysisManager default file type
105 in the FCALRunAction constructor. 105 in the FCALRunAction constructor.
106 106