source: trunk/examples/extended/radioactivedecay/exrdm/README@ 1337

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1
2 =========================================================
3 Geant4 - an Object-Oriented Toolkit for Simulation in HEP
4 =========================================================
5
6 Extended Example for G4RadioactiveDecay
7 --------------------
8
9 The exRDM is created to show how to use the G4RadioactiveDecay process to simulate the decays of
10 radioactive isotopes as well as the induced radioactivity resulted from nuclear interactions.
11
12 In this example a simple geometry consists of a cylindric target placed in the centre of a tube detector
13 is constructed. Various primary event generation and tallying options are available. Further documentations
14 are available at
15
16 http://reat.space.qinetiq.com/septimess/exrdm
17
18 1. GEOMETRY
19
20 Material: There are 7 pre-defined materials:
21 "Vacuum" "Air" "Silicon" "Aluminium" "Lead" "Germanium" and "CsI"
22
23 User can add a new material at the "PreIni" state, using the command
24 /geometry/material/add
25
26 For the geometry, the world is filled with "Air" and there are two components in it
27
28 - Target: A cylinder placed at the origin along the z-axis. The default size of the cylinder is
29 0.5 cm radius and 1 cm in length, and its default material is "CsI".
30
31 - Detector:A tube cerntred at the origin along the z-axis, with inner radius matching the
32 radius of the target. The default thickness of the tube is 2 cm and it is
33 5 cm long. The default material is "Germanium".
34
35 The user can change the target/detector size and material at the at the "PreIni" state, using the
36 commands in the directory
37
38 /exrdm/det
39
40 2. PHYSICS
41
42 The following physics processes are included by default:
43
44 - Standard electromagnetic:
45 photo-electric effect
46 Compton scattering
47 pair production
48 bremsstrahlung
49 ionization
50 multiple scattering
51 annihilation
52
53 - Decay
54
55 - Radioactive Decay
56 By default it is applied through out the geometry. The user can limit it to just the target by
57 commands
58
59 /grdm/noVolumes
60 /grdm/selectVolume Target
61
62 - Hadronic processes:
63 Hadronic processes are not invoked by default. They can be activated by the user at the "PreIni"
64 state via the command
65
66 /exrdm/phys/SelectPhysics
67
68 The options are:
69
70 "Hadron" - Physicslist comsists of Binary_Cascade, HP_Neutron, QGSP, and LHEP, or
71 the standdard hadron physics list avaible in the G4 distribution, i.e.
72 "QGSP_BERT", "QGSP_BIC", "QGSP_HP", "LHEP_BERT", "LHEP_BERT_HP", "LHEP_BIC",
73 "LHEP_BIC_HP".
74
75 3. EVENT:
76
77 The event generator is based on the G4GeneralParticleSource (GPS) which allows the user to
78 control all aspects of the initial states of the events. In this example, however, only simple features
79 of the GPS are employed to generate the incident beam or the initial radio-isotopes. By default the
80 incident particle is travelling along the + z-axis and the incident position is at the -Z end
81 of the geometry.
82
83 4. DETECTOR RESPONSE:
84
85 No Geant4 HITS and SD are defined in this example. If the variable "G4ANALYSIS_USE" is defined, all
86 the relevant information of the simulation is collected at the "UserSteppingAction" stage. These
87 include:
88
89 - Emission particles in the RadioactiveDecay process:
90 particle PDGcode,
91 partilce kinetic energy,
92 particle creation time,
93 particle weight.
94
95 Note: the residual nuclei is not considered as an emitted particle.
96
97 - Radio-Isotopes. All the radioactive isotopes produced in the simulation:
98 isotope PDGcode,
99 isotope creation time,
100 isotope weight.
101
102 - Energy depositions in the target and detector by prodicts of the RadioactiveDecay process:
103 energy depostion (positive volue for target and negative for detector),
104 time,
105 weight.
106
107 5. VISUALIZATION:
108
109 Visualisation of the geometry and the tracks is possible with many of the G4 visualisation packages. An
110 example of display the geometry and tracks using VRML is given in the macro file macros/vis.mac.
111
112 6. ANALYSIS:
113
114 This example implements an AIDA-compliant analysis system as well as the ROOT system, for accumulating
115 and output histograms and ntuples. If the the user has an AIDA-compliant tool such as
116 AIDAJNI, ANAPHE, OpenScientist or PI installed, the analysis part of this example can
117 be activated by
118
119 setenv G4ANALYSIS_USE 1
120
121 before building the executable.
122
123 The user can also use the executable with the ROOT system, if it is available. This is done by
124
125 setenv G4ANALYSIS_USE_ROOT 1
126
127 again before the compilation. The AIDA and ROOT systems can be used individually, or in parallel
128 at the same time!
129
130 If no analysis system is activated, there is no output file produced apart from the screen dump.
131 A file called "exrdm.aida" is produced by default for AIDA system and "exrdm.root" if the ROOT
132 system is selected.
133
134 The user can change the name of this output file with the command
135
136 /histo/fileName new-filename
137
138 The output AIDA file by default is in xml format. The AIDA system allows the use of other file format
139 such as "root" and "hbook". User can change the output format to "hbook" or "root" using the command
140 /histo/fileType.e.g.
141
142 /histo/fileType hbook
143 /histo/fileType root
144
145 When "root" format is selected for the AIDA system, the output AIDA file name is changed to
146 fileName_aida.root. This is to separate it from the the ROOT system output file fileName.root, in case
147 both systems are used.
148
149 The output file, in "aida" or "hbook" or "root" format, conatins the 3 ntuples (100,200,300) which have
150 been described in section 4. In addition, there are 7 histograms in the file:
151
152 histogram 10: The Pulse Height Spectrum (PHS) of the target.
153 histogram 11: The PHS of the detector.
154 histogram 12: The combined PHS of the target and detector.
155 histogram 13: The anti-coincidece PHS of the target.
156 histogram 14: The anti-coincidece PHS of the detector.
157 histogram 15: The coincidece PHS between the target and detector.
158 histogram 16: The emitted particle energy spectrum.
159
160 The binnings of each histogram can be changed with the command
161
162 /histo/setHisto
163
164 It is assumed the detector and target pulses both have an integration time of 1 microsecond, and the
165 gate is 2 microsecond for the coincidence spectrum. The target and detctor have a threshold of 10 keV
166 in the anti-/coincidence modes.
167
168 Histograms 10-15 were derived from the same data stored in ntuple-300(the energy depositions), while
169 Histogram 16 is obtained with data in ntuple-100 (the emission particles). The user should be able to
170 reproduce these histograms, or new histograms, with the ntuple data in an off-line analyis tool.
171
172 7. GETTING STARTED:
173
174 i) If you have an AIDA-compliant analysis system installed than you shall switch on the analysis part of
175 example by
176
177 setenv G4ANALYSIS_USE 1
178
179 in addition if you want to add the ROOT link to the ROOT system, do
180
181 setenv G4ANALYSIS_USE_ROOT 1
182
183 Otherwise make sure the G4ANALYSIS_USE and G4ANALYSIS_USE_ROOT are not definded
184
185 unsetenv G4ANALYSIS_USE
186 unsetenv G4ANALYSIS_USE_ROOT
187
188 ii) Build the exRDM executable:
189
190 cd to exrdm
191 gmake clean
192 gmake
193
194 Depends on the setup, gmake will create tmp and bin directories in your $G4TMP and $G4BIN directories.
195 The executable, named exRDM, will be in $G4BIN/$G4SYSTEM/ directory.
196
197 iii) Run the executable: while in the exrdm directory do
198
199 $G4BIN/$G4SYSTEM/exRDM exrdm.in
200
201 If all goes well, the execution shall be terminated in a few seconds. If G4ANALYSIS_USE is defined, one
202 should see a "proton.aida" file created. If G4ANALYSIS_USE_ROOT is defined, there will be
203 a proton.root file in the same directory.
204
205 8. FURTHER EXAMPLES:
206
207 There are a number of g4mac files in the ./macros subdirectory, to show the features of the
208 G4RadioactiveDecay process. Most of them will lead to the creation of an aida file in the same name
209 of the micro file, which can be examed and analysed with an analysis tool such as OpenScientist ,or JAS3.
210
211 vrml.mac: to visulise the geometry and the incident of one 100 MeV Cf240 isotope and its decay. A vrml
212 file (g4_xx.vrml) is created at the end. If a default vrml viewer has been set, one shall
213 see the geometru and track displayed automatically.
214
215 u238c.mac: shows the decays of the U238 chain in analogue MC mode.
216
217 th234c-b.mac: shows the decays of Th234 in variance reduction MC mode. All its secondaies in along the
218 decay chains are generated. The default source profile and decay biasing schemes are used
219 to determine the decay times and weights of the secondaries.
220
221 proton-1gev.mac: simulation of 1 GeV protons incident on a lead target. The decays of the radio-siotopes
222 created in the proton-lead interactions are simulated with RadioactiveDecay in analogue
223 MC mode.
224
225 proton-b.mac: same as proton-1geV.mac, but the decays of the radio-siotopes created in the proton-lead
226 interactions are simulated with RadioactiveDecay in variance reduction MC mode. The isotopes
227 and those along the decay chains are forced to decay in the time windows specified by the
228 user in file measures.data, and the weights of the decay products are determined by the
229 beam profile as defined in the beam.data file and their decay times.
230
231 one-iso.mac: simple macro file to show how to simulate the decay of a specific radio-isotope. User can
232 edit it to simulate which ever isotope he/she likes to try.
233
234 neutron.mac: macrofile to show the incident of low energy neutrons on an user specified NaI target and
235 the decays of the induced radio-isotopes. This shows how to define a new material in exrdm.
236
237 ne24.mac: this shows the decays of Ne-24 to Na-24 in variance reduction MC mode. Further decays of Na-24
238 are not simulated by applying the nucleuslimits in RadioactiveDecay. Two runs are carried out.
239 One with the bracjing ratio biasing applied and one without.
240
241 multiple-source.mac: to show the decays of different isotopes uniformly distributed through the target
242 volume in a single run.
243
244 isotopes.mac: to show the decays of a number of different isotopes in a single macro file.
245
246
247 f24.mac: to show the different treatments one can apply to the decays of F24. i) the complete decay chain
248 from F24 to Mg24, in analogue mode; ii) the complete chain, but in variance reduction mode;
249 iii) restrict to the decay of F24 only in analogue mode; iv) restrict to the decay of F24 only but
250 in variance reduction mode.
251
252 as74.mac: The decays of As74 which has a rather complicated decay scheme. i) in analogue MC mode; ii) in
253 variance reduction MC mode.
254
255 test.mac: macro used to check if the right physics processes are assigned to different particles.
256
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