1 | $Id: README,v 1.3 2008/09/26 20:15:04 maire Exp $ |
---|
2 | ------------------------------------------------------------------- |
---|
3 | |
---|
4 | ========================================================= |
---|
5 | Geant4 - an Object-Oriented Toolkit for Simulation in HEP |
---|
6 | ========================================================= |
---|
7 | |
---|
8 | TestEm17 |
---|
9 | -------- |
---|
10 | This example is intended to check implementation of the processes |
---|
11 | of muon interactions: ionization, direct (e+,e-) production, |
---|
12 | bremsstrahlung, mu-nuclear interaction. |
---|
13 | It allows to compute differential cross sections (as function of the |
---|
14 | energy tranfered to secondaries), total cross sections and to compare |
---|
15 | with analytic calculations. |
---|
16 | |
---|
17 | 1- GEOMETRY DEFINITION |
---|
18 | |
---|
19 | It is a single box of homogeneous medium. |
---|
20 | Two parameters define the geometry : |
---|
21 | - the material of the box, |
---|
22 | - the (full) size of the box. |
---|
23 | |
---|
24 | The default geometry (1 m of Iron) is constructed in |
---|
25 | DetectorConstruction, but the above parameters can be changed |
---|
26 | interactively via the commands defined in DetectorMessenger. |
---|
27 | |
---|
28 | 2- PHYSICS LIST |
---|
29 | |
---|
30 | The physics list contains only electromagnetic processes for muon, |
---|
31 | adding G4MuNuclearInteraction and seting of upper energy range limit |
---|
32 | to 1000 PeV). |
---|
33 | |
---|
34 | Standard (default) and g4v52 (frozen at the release Geant4 v.5.2) |
---|
35 | physics can be choosen. |
---|
36 | |
---|
37 | 3- AN EVENT : THE PRIMARY GENERATOR |
---|
38 | |
---|
39 | The primary kinematic consists of a single particle starting at the edge |
---|
40 | of the box. The type of the particle and its energy are set in |
---|
41 | PrimaryGeneratorAction (mu+ 10 TeV), and can be changed via the G4 |
---|
42 | build-in commands of ParticleGun class (see the macros provided with |
---|
43 | this example). |
---|
44 | |
---|
45 | 4- PHYSICS |
---|
46 | |
---|
47 | The incident particle is a muon. During the tracking, secondary |
---|
48 | particles are killed. |
---|
49 | |
---|
50 | The number of interactions are plotted as a function of the energy |
---|
51 | transfered to the secondaries. |
---|
52 | The total number of interactions is recorded, and the total crossSection |
---|
53 | computed from this. |
---|
54 | |
---|
55 | At EndOfRun, the above results are compared with analytic calculations. |
---|
56 | The functions which compute the theoritical crossSections have been |
---|
57 | provided by the G4 MEPhI group, and grouped in MuCrossSection class. |
---|
58 | |
---|
59 | 5- HISTOGRAMS |
---|
60 | |
---|
61 | The test contains 4 built-in 1D histograms, which are managed by the |
---|
62 | HistoManager class and its Messenger. |
---|
63 | |
---|
64 | 1 Monte-Carlo relative transferred energy distribution histo |
---|
65 | (log10(eps/Emu kin) for knock-on electrons (ionization) |
---|
66 | 2 -"- direct (e+,e-) pair production |
---|
67 | 3 -"- bremsstrahlung |
---|
68 | 4 -"- nuclear interaction |
---|
69 | |
---|
70 | The histos can be activated individually with the command : |
---|
71 | /testem/histo/setHisto id nbBins valMin valMax : min and max values of |
---|
72 | log10(eps/Emu kin). |
---|
73 | |
---|
74 | At EndOfRun the corresponding histos for analytic calculations are |
---|
75 | automatically created anf filled (histo 6 to 9), and the comparison |
---|
76 | (G4 divided by theory) is done in histos 11 to 14. |
---|
77 | |
---|
78 | One can control the name and the type of the histograms file with |
---|
79 | the commands: |
---|
80 | /testem/histo/setFileName name (default testem17) |
---|
81 | /testem/histo/setFileType name (default root) |
---|
82 | |
---|
83 | Note that, by default, histograms are disabled. To activate them, |
---|
84 | uncomment the flag G4ANALYSIS_USE in GNUmakefile. |
---|
85 | |
---|
86 | 6- VISUALIZATION |
---|
87 | |
---|
88 | The Visualization Manager is set in the main(). |
---|
89 | The initialisation of the drawing is done via the commands |
---|
90 | /vis/... in the macro vis.mac. To get visualisation: |
---|
91 | > /control/execute vis.mac |
---|
92 | |
---|
93 | The detector has a default view which is a longitudinal view of the |
---|
94 | box. |
---|
95 | |
---|
96 | The tracks are drawn at the end of event, and erased at the end of run. |
---|
97 | |
---|
98 | 7- HOW TO START ? |
---|
99 | |
---|
100 | compile and link to generate an executable |
---|
101 | % cd geant4/examples/extended/electromagnetic/TestEm17 |
---|
102 | % gmake |
---|
103 | |
---|
104 | execute TestEm17 in 'batch' mode from macro files : |
---|
105 | % TestEm17 allproc.mac |
---|
106 | |
---|
107 | execute TestEm17 in 'interactive mode' with visualization : |
---|
108 | % TestEm17 |
---|
109 | Idle> control/execute vis.mac |
---|
110 | .... |
---|
111 | Idle> type your commands |
---|
112 | .... |
---|
113 | Idle> exit |
---|
114 | |
---|
115 | 8- USING HISTOGRAMS |
---|
116 | |
---|
117 | By default the histograms are not activated. To activate histograms |
---|
118 | the environment variable G4ANALYSIS_USE should be defined. For instance |
---|
119 | uncomment the flag G4ANALYSIS_USE in GNUmakefile. |
---|
120 | |
---|
121 | Before compilation of the example it is optimal to clean up old files: |
---|
122 | gmake histclean |
---|
123 | gmake |
---|
124 | |
---|
125 | To use histograms, at least one of the AIDA implementations should be |
---|
126 | available. See InstallAida.txt |
---|
127 | |
---|