| Geant4 Cross Reference |
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2
3 =========================================
4 Geant4 - an Object-Oriented Toolkit for S
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6
7 gammaray_telescope
8 ------------------
9 F. Longo, R. Giannitrapan
10 June 2003
11
12 ----------------------------------------------
13 Acknowledgments to GEANT4 people, in particula
14 A. Pfeiffer, M. G. Pia and G. Cosmo
15 ----------------------------------------------
16
17 GammaRayTel is an example of application of Ge
18 environment. It simulates a typical telescope
19 the detector setup is composed by a tracker ma
20 subdivided in ladders and strips, a CsI calori
21 anticoincidence system. In this version, the t
22 sensitive but only the hits on the tracker str
23 information (energy deposition, position etc.)
24 ASCII file for subsequent analysis.
25
26 Relevant information from the simulation is pr
27 class and saved, through the G4AnalysisManager
28 Tuples.
29
30 a) Macros for the visualization of geometry
31 OpenGL, VRML and DAWN drivers
32
33 b) Implementation of messengers to change so
34 the detector geometry, the particle gener
35 manager (if present) runtime
36
37 c) Readout geometry mechanism to describe an
38 subdivisions of the planes of the tracker
39 affecting in a relevant way the simulatio
40
41 d) Histogramming facilities are presently pr
42
43 e) User interfaces via Xmotif or normal term
44
45
46 1. Setting up the environment variables
47 ---------------------------------------
48
49 - Setup for storing ASCII data
50
51 If you want to store the output data in an A
52 where x stays for the run number. You should
53 variable:
54
55 setenv G4STORE_DATA 1
56
57 - Setup for Visualization
58
59 IMPORTANT: be sure that your Geant4 installa
60 with the proper visualization drivers; for d
61 file geant4/source/visualization/README.
62
63 To use the visualization drivers set the fol
64 your local environment:
65
66 setenv G4VIS_USE_OPENGLX 1 # OpenGL visuali
67 setenv G4VIS_USE_DAWNFILE 1 # DAWN file
68 setenv G4VIS_USE_VRMLFILE 1 # VRML file
69 setenv G4VRMLFILE_VIEWER vrmlview # If inst
70
71 - Setup for Xmotif user interface
72
73 setenv G4UI_USE_XM 1
74
75 - Set up for analysis
76
77 To compile the GammaRayTel example with the
78 set the following variables
79
80 setenv G4ANALYSIS_USE 1 # Use the analysis t
81
82 2. Sample run
83 -------------
84
85 To run a sample simulation with gamma tracks
86 the detector in its standard configuration an
87 visualization, execute the following command
88 directory:
89
90 $G4WORKDIR/bin/$G4SYSTEM/GammaRayTel
91
92 It is possible also to run three different co
93 macro1.mac, macro2.mac and macro3.mac for vis
94 and DAWN respectively) with the following com
95
96 $G4WORKDIR/bin/$G4SYSTEM/GammaRayTel macroX.m
97
98 where X can be 1, 2 or 3. Be sure to have the
99 the preceding section) and the proper visuali
100 your local G4 installation (see geant4/source
101 more information).
102
103
104 3. Detector description
105 -----------------------
106
107 The detector is defined in GammaRayTelDetecto
108 It is composed of a Payload with three main d
109 Calorimeter (CAL) and an Anticoincidence syst
110
111 The standard configuration is made of a TKR o
112 4 * 4 Si single sided silicon detectors with
113 5 layers of CsI, each made of 2 views of 12 C
114 4 lateral panels and a top layer of plastic s
115 complete the configuration.
116 The Si detectors are composed of two silicon
117 aligned along the X axis in one plane and alo
118
119 The following baseline configuration is adopt
120
121 GEOMETRICAL PARAMETER VALUE
122
123 Converter Thickness 300 micron
124 Silicon Thickness 400 micron
125 Silicon Tile Size XY 9 cm
126 Silicon Pitch 200. micrometer
127 Views Distance 1. mm
128 CAL Bar Thickness 1.5 cm
129 ACD Thickness 1. cm
130
131 It is possible to modify in some way this con
132 commands defined in GammaRayTelDetectorMessen
133 This feature is available in the UI through t
134 "/payload/" (see the help command in the UI f
135
136 4. Physics processes
137 --------------------
138
139 This example uses a modular physics list, wit
140 (see the web page http://cmsdoc.cern.ch/~hpw/
141 physics lists), the Standard or the LowEnergy
142
143 5. Particle Generator
144 ---------------------
145
146 The GammaRayTelParticleGenerationAction and i
147 the incident flux of particles, from a specif
148 isotropic background. In the first case parti
149 surface which diameter is perpendicular to th
150 case the arrival directions are isotropic.
151
152 The user can define also between two spectral
153 monochromatic or with a power-law dependence.
154 generator parameters are accessible through t
155 UI help for more information). We are plannin
156 releases of this example, the General Particl
157
158 6. Hit
159 ------
160
161 In this version the hits from the TKR the CAL
162 Only the hit from the TRK are saved. Each TKR
163 information
164
165 a) ID of the event (this is important for mu
166 b) Energy deposition of the particle in the
167 c) Number of the strip
168 d) Number of the plane
169 e) Type of the plane (1=X 0=Y)
170 f) Position of the hit (x, y, z) in the refe
171
172 The hit information are saved on an ASCII fil
173 N is the progressive ID number associated to
174
175 7. Analysis
176 -----------
177
178 Relevant information from the simulation is pr
179 class and saved, through the G4AnalysisManager
180 Tuples. The output file is written in ROOT for
181 XML (or Hbook) by changing the appropriate #in
182 No external software is required (apart from t
183 must be installed and a FORTRAN compiler must
184
185 Keep in mind that the actual implementation o
186 is of a pedagogical nature, so we kept it as
187
188 The actual analysis produces some histograms
189 Both the histograms and the ntuple are saved
190 "gammaraytel.root". Please note that in a mul
191 the last run always override the root file.
192
193 8. Histogramming
194 ----------------
195
196 The 1D histograms contain the energy depositi
197 the TKR and the hits distribution along the X
198 (note again that these histograms have been c
199 motivation than for physical one).
200
201 These histograms are filled and updated at ev
202 with each new run; the scale of the histogram
203 the detector geometry.
204
205 Through a messenger it is possible to set som
206 the UI subtree "/analysis/" (use the UI help
207
208 In this example we only show the use of very
209 simulation/analysis framework.
210
211 9. Digi
212 -------
213
214 For the TKR also the digits corresponding to
215 A digi is generated when the hit energy depos
216 (in this example setted at 120 keV).
217 The TKR digi information are stored on the sa
218
219 a) ID of the event (this is important for mu
220 b) Number of the strip
221 c) Number of the plane
222 d) Type of the plane (1=X 0=Y)
223
224 10. Classes Overview
225 --------------------
226
227 This is the overview of the classes defined i
228
229 GammaRayTelPrimaryGeneratorAction
230 User action for primaries generator
231
232 GammaRayTelPrimaryGeneratorMessenger
233 Messenger for interactive particle generat
234 parameters modification via the User Inter
235
236 GammaRayTelPhysicsList
237 Determination of modular physics classes
238
239 GammaRayTelDetectorConstruction
240 Geometry and material definitions for the
241
242 GammaRayTelDetectorMessenger
243 Messenger for interactive geometry paramet
244 modification via the User Interface
245
246 GammaRayTelAnalysis
247 Analysis manager class (experimental)
248
249 GammaRayTelAnalysisMessenger
250 Messenger for interactive analysis options
251 via the User Interface
252
253 GammaRayTelRunAction
254 User run action class
255
256 GammaRayTelEventAction
257 User event action class
258
259 GammaRayTelTrackerHit
260 Description of the hits on the tracker
261
262 GammaRayTelDigi
263 Description of the digi on the tracker
264
265 GammaRayTelDigitizer
266 Description of the digitizer for the track
267
268 GammaRayTelTrackerSD
269 Description of the TKR sensitive detector
270
271 GammaRayTelAnticoincidenceHit
272 Description of the hits on the anticoincid
273
274 GammaRayTelAnticoincidenceSD
275 Description of the ACD sensitive detector
276
277 GammaRayTelCalorimeterHit
278 Description of the hits on the calorimeter
279
280 GammaRayTelCalorimeterSD
281 Description of the CAL sensitive detector