| Geant4 Cross Reference |
>> 1 $Id: README,v 1.4 2008-09-26 20:26:01 maire Exp $
1 ---------------------------------------------- 2 -------------------------------------------------------------------
2 3
3 ========================================= 4 =========================================================
4 Geant4 - an Object-Oriented Toolkit for S 5 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
5 ========================================= 6 =========================================================
6 7
7 TestEm18 8 TestEm18
8 -------- 9 --------
9 This example allows to study the various c << 10 This example allows to study the energy lost by a charged particle in a
10 by a charged particle in a single layer of << 11 single layer, due to ionization and bremsstrahlung. Results are compared to
11 See any textbook of interactions of charge << 12 'reference' values.
12 1- geant4.web.cern.ch --> UserSupport -- <<
13 2- lappweb.in2p3.fr/~maire/tutorials/ind <<
14 13
15 1- GEOMETRY DEFINITION 14 1- GEOMETRY DEFINITION
16 15
17 It is a simple cubic box of homogeneous ma << 16 It is a single box of homogeneous medium.
18 Two parameters define the geometry : 17 Two parameters define the geometry :
19 - the material of the box, 18 - the material of the box,
20 - the thickness of the box. << 19 - the (full) size of the box.
21 20
22 The default geometry (1 cm of water) is co 21 The default geometry (1 cm of water) is constructed in DetectorConstruction,
23 but the above parameters can be changed in 22 but the above parameters can be changed interactively via the commands
24 defined in DetectorMessenger. 23 defined in DetectorMessenger.
25 24
26 2- PHYSICS 25 2- PHYSICS
27 26
28 The physics list contains the 'standard' e 27 The physics list contains the 'standard' electromagnetic processes.
29 However the MultipleScattering is not regi 28 However the MultipleScattering is not registered, in order to focuse on
30 fluctuations of to energy loss alone. << 29 fluctuations due to energy loss alone.
31 30
32 3- BEAM 31 3- BEAM
33 32
34 The primary kinematic is a single particle 33 The primary kinematic is a single particle starting at the edge
35 of the box. The type of the particle and i 34 of the box. The type of the particle and its energy are set in
36 PrimaryGeneratorAction (e- 10 MeV), and ca 35 PrimaryGeneratorAction (e- 10 MeV), and can be changed via the G4
37 build-in commands of ParticleGun class. 36 build-in commands of ParticleGun class.
38 37
39 4- RUN 38 4- RUN
40 39
41 During the tracking of the incident partic << 40 During the tracking of the incident particle, the secondary particles
42 particles are immediately killed, after th << 41 are immediately killed, after that their energy has been registered
43 (see SteppingAction and StackingAction). << 42 (see StackingAction).
44 Therefore, we study here the various compo << 43 Therefore, we study here the total energy lost by the incident particle,
45 by the incident particle, not the energy d << 44 not the energy deposited in a layer of finite thickness.
46 thickness. <<
47 With the option /testEm/trackSecondaries o <<
48 deposited in the layer. See edep.mac <<
49 45
50 At EndOfRun, the above results are compare 46 At EndOfRun, the above results are compared with 'reference' values,
51 i.e. the input data read from EnergyLoss a << 47 i.e. the values read from EnergyLoss tables.
52 See reference 2 : Energy-Range relation, s <<
53 48
54 5- HISTOGRAMS 49 5- HISTOGRAMS
55 50
56 The test contains 13 built-in 1D histogram << 51 The test contains 6 built-in 1D histograms, which are managed by
57 G4AnalysisManager and its Messenger. 52 G4AnalysisManager and its Messenger.
58 << 53
59 1 step size of primary track << 54 1 continuous energy loss along primary track
60 2 energy continuously deposited al << 55 2 energy from secondaries
61 3 energy transfered to secondaries << 56 3 total energy lost by primary track (1+2)
62 4 energy transfered to secondaries << 57 4 energy spectrum of e-+
63 5 energy transfered to secondaries << 58 5 energy spectrum of gamma
64 6 total energy transfered to secon << 59 6 step size of primary track
65 7 total energy lost by primary tra << 60
66 8 total energy lost by primary tra <<
67 9 energy continuously deposited al <<
68 10 total energy deposited <<
69 11 energy spectrum of gamma <<
70 12 energy spectrum of e- <<
71 13 energy spectrum of e+ <<
72 <<
73 The histograms are defined in HistoManager 61 The histograms are defined in HistoManager.
74 62
75 The histos can be activated individually w 63 The histos can be activated individually with the command :
76 /analysis/h1/set id nbBins valMin valMax u 64 /analysis/h1/set id nbBins valMin valMax unit
77 where 'unit' is the desired unit for the h 65 where 'unit' is the desired unit for the histo (MeV or KeV, cm or mm, etc..)
78 66
79 One can control the name of the histograms 67 One can control the name of the histograms file with the command:
80 /analysis/setFileName name (default test 68 /analysis/setFileName name (default testem18)
81 69
82 It is possible to choose the format of the 70 It is possible to choose the format of the histogram file : root (default),
83 xml, csv, by using namespace in HistoManag << 71 xml, csv, by using namespace in HistoManager.hh
84 For convenience, few simple Root macros ar << 72
85 It is also possible to print selected hist 73 It is also possible to print selected histograms on an ascii file:
86 /analysis/h1/setAscii id 74 /analysis/h1/setAscii id
87 All selected histos will be written on a f 75 All selected histos will be written on a file name.ascii (default testem18)
88 76
89 6- VISUALIZATION 77 6- VISUALIZATION
90 78
91 The Visualization Manager is set in the ma 79 The Visualization Manager is set in the main().
92 The initialisation of the drawing is done 80 The initialisation of the drawing is done via the commands
93 /vis/... in the macro vis.mac. To get visu 81 /vis/... in the macro vis.mac. To get visualisation:
94 > /control/execute vis.mac 82 > /control/execute vis.mac
95 83
96 The detector has a default view which is a 84 The detector has a default view which is a longitudinal view of the box.
97 The tracks are drawn at the end of event, 85 The tracks are drawn at the end of event, and erased at the end of run.
98 86
99 7- HOW TO START ? 87 7- HOW TO START ?
100 88
101 execute TestEm18 in 'batch' mode from macr 89 execute TestEm18 in 'batch' mode from macro files :
102 % TestEm18 electron.mac 90 % TestEm18 electron.mac
103 91
104 execute TestEm18 in 'interactive mode' wit 92 execute TestEm18 in 'interactive mode' with visualization :
105 % TestEm18 93 % TestEm18
106 Idle> control/execute vis.mac 94 Idle> control/execute vis.mac
107 .... 95 ....
108 Idle> type your commands 96 Idle> type your commands
109 .... 97 ....
110 Idle> exit 98 Idle> exit
111 <<
112 Macros provided in this example: <<
113 - csda.mac: test independance of user step m <<
114 - edep.mac: track secondary particles and pl <<
115 - electron.mac: e- (10 MeV) on 1 cm of water <<
116 - ion.mac: ion C12 (4 GeV) on 1 cm of water <<
117 - muon.mac: mu+ (1 TeV) on 1 m of water <<
118 - pixe.mac: proton (20 MeV) on 50 um of gold <<
119 - proton.mac: proton (1 GeV) on 10 cm of wat <<
120 - plotHisto.C, pixe.C: Root macros <<
121 <<
122 Macros to be run interactively: <<
123 - vis.mac: To activate visualization <<