| Geant4 Cross Reference |
>> 1 $Id: README 66241 2012-12-13 18:34:42Z gunter $
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 TestEm17 8 TestEm17
8 -------- 9 --------
9 This example is intended to check impl 10 This example is intended to check implementation of the processes
10 of muon interactions: ionization, dire << 11 of muon interactions: ionization, direct (e+,e-) production,
11 pair production, bremsstrahlung, and mu-nucl << 12 bremsstrahlung, mu-nuclear interaction.
12 It allows to compute differential cross sect 13 It allows to compute differential cross sections (as function of the
13 energy transfered to secondaries), total cro << 14 energy transfered to secondaries), total cross sections and to compare
14 with analytic calculations. 15 with analytic calculations.
15 16
16 1- GEOMETRY DEFINITION 17 1- GEOMETRY DEFINITION
17 18
18 It is a single box of homogeneous medium. 19 It is a single box of homogeneous medium.
19 Two parameters define the geometry : 20 Two parameters define the geometry :
20 - the material of the box, 21 - the material of the box,
21 - the (full) size of the box. 22 - the (full) size of the box.
22 23
23 The default geometry (1 m of Iron) is constr 24 The default geometry (1 m of Iron) is constructed in
24 DetectorConstruction, but the above paramete 25 DetectorConstruction, but the above parameters can be changed
25 interactively via the commands defined in De 26 interactively via the commands defined in DetectorMessenger.
26 27
27 2- PHYSICS LIST 28 2- PHYSICS LIST
28 29
29 The Physics List of the example uses the mai << 30 The Physics List of the example uses the main local physics constructor
30 (builder) called "local", which includ << 31 (builder) which called "standard". In this builder a limited set
31 processes under study. As an alternati << 32 of physics processes are defined for muons, pions and proton:
32 and "emstandard_opt4" constructors may << 33 ionisation, bremsstrahlung and e+e- pair production. Energy range
33 << 34 for these processes is from 100*eV to 1000*PeV.
34 Default energy range for EM processes <<
35 is from 100*eV to 1000*PeV. <<
36 35
37 Optionally "muNucl" builder may be add 36 Optionally "muNucl" builder may be added activating muon-nuclear
38 inelastic interaction. 37 inelastic interaction.
39 38
40 3- AN EVENT : THE PRIMARY GENERATOR 39 3- AN EVENT : THE PRIMARY GENERATOR
41 40
42 The primary kinematic consists of a single p 41 The primary kinematic consists of a single particle starting at the edge
43 of the box. The type of the particle and its 42 of the box. The type of the particle and its energy are set in
44 PrimaryGeneratorAction (mu+ 10 TeV), and can 43 PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4
45 build-in commands of ParticleGun class (see 44 build-in commands of ParticleGun class (see the macros provided with
46 this example). 45 this example).
47 46
48 4- PHYSICS 47 4- PHYSICS
49 48
50 The incident particle is a muon. During the 49 The incident particle is a muon. During the tracking, secondary
51 particles are killed. 50 particles are killed.
52 51
53 The number of interactions are plotted as a 52 The number of interactions are plotted as a function of the energy
54 transfered to the secondaries. 53 transfered to the secondaries.
55 The total number of interactions is recorded << 54 The total number of interactions is recorded, and the total cross section
56 section computed from this. << 55 computed from this.
57 56
58 At RunAction::EndOfRun(..), the above << 57 At EndOfRun, the above results are compared with analytic calculations.
59 calculations. The functions computing << 58 The functions which compute the theoretical cross sections have been
60 provided by the G4 MEPhI group, and implemen << 59 provided by the G4 MEPhI group, and grouped in MuCrossSections class.
61 60
62 5- HISTOGRAMS 61 5- HISTOGRAMS
63 62
64 The test contains built-in 1D histograms for << 63 The test contains 4 built-in 1D histograms, which are managed by the
65 Monte Carlo simulation, which are mana << 64 HistoManager class and its Messenger.
66 and its Messenger: <<
67 65
68 1 Relative muon transferred energy dis << 66 1 Monte-Carlo relative transferred energy distribution histo
69 (log10(eps/Emu kin) for knock-on e 67 (log10(eps/Emu kin) for knock-on electrons (ionization)
70 2 -"- direct (e+,e-) pair production << 68 2 -"- direct (e+,e-) pair production
71 3 -"- bremsstrahlung by muons << 69 3 -"- bremsstrahlung
72 4 -"- nuclear interaction by muons << 70 4 -"- nuclear interaction
73 5 ionistion for hadrons << 71
74 6 (e+,e-) pair production by hadrons <<
75 7 bremsstrahlung by hadrons <<
76 8 direct mu+,mu- pair production by muons <<
77 <<
78 The histos can be activated individually wit 72 The histos can be activated individually with the command :
79 /testem/histo/setHisto id nbBins valMin val 73 /testem/histo/setHisto id nbBins valMin valMax :
80 min and max values of log10(eps/Emu 74 min and max values of log10(eps/Emu kin).
81 75
82 At EndOfRun the corresponding histos for ana 76 At EndOfRun the corresponding histos for analytic calculations are
83 automatically created and filled (histo 11 t << 77 automatically created and filled (histo 11 to 14).
84 78
85 One can control the name and the type of the 79 One can control the name and the type of the histograms file with
86 the command: 80 the command:
87 /testem/histo/setFileName name (default te 81 /testem/histo/setFileName name (default testem17)
88 << 82
>> 83 It is possible to choose the format of the histogram file :
>> 84 root (default), xml, csv, by using namespace in HistoManager.hh
>> 85
89 6- VISUALIZATION 86 6- VISUALIZATION
90 87
91 The Visualization Manager is set in the main 88 The Visualization Manager is set in the main().
92 The initialisation of the drawing is done vi 89 The initialisation of the drawing is done via the commands
93 /vis/... in the macro vis.mac. To get visual 90 /vis/... in the macro vis.mac. To get visualisation:
94 > /control/execute vis.mac 91 > /control/execute vis.mac
95 92
96 The detector has a default view which is a l 93 The detector has a default view which is a longitudinal view of the
97 box. 94 box.
98 95
99 The tracks are drawn at the end of event, an 96 The tracks are drawn at the end of event, and erased at the end of run.
100 97
101 7- HOW TO START ? 98 7- HOW TO START ?
102 99
103 execute TestEm17 in 'batch' mode from macro 100 execute TestEm17 in 'batch' mode from macro files :
104 % TestEm17 allproc.mac 101 % TestEm17 allproc.mac
105 102
106 execute TestEm17 in 'interactive mode' with 103 execute TestEm17 in 'interactive mode' with visualization :
107 % TestEm17 104 % TestEm17
108 Idle> control/execute vis.mac 105 Idle> control/execute vis.mac
109 .... 106 ....
110 Idle> type your commands 107 Idle> type your commands
111 .... 108 ....
112 Idle> exit 109 Idle> exit