| Geant4 Cross Reference |
1 ---------------------------------------------- 1 -------------------------------------------------------------------
>> 2 $Id: README,v 1.11 2004/05/18 14:57:48 ribon Exp $
2 ---------------------------------------------- 3 -------------------------------------------------------------------
3 4
4 ========================================= 5 =========================================================
5 Geant4 - Composite calor 6 Geant4 - Composite calorimeter example
6 ========================================= 7 =========================================================
7 8
8 README 9 README
9 --------------------- 10 ---------------------
10 11
11 CompositeCalorimeter is an example of a test- 12 CompositeCalorimeter is an example of a test-beam simulation used
12 by the CMS Collaboration to validate Geant4 a 13 by the CMS Collaboration to validate Geant4 against real data taken
13 (in 1996) in a CMS Hadron calorimeter test-be 14 (in 1996) in a CMS Hadron calorimeter test-beam.
14 The name "Composite" for this example emphasi 15 The name "Composite" for this example emphasizes that, although the
15 test-beam had the goal of studying the hadron 16 test-beam had the goal of studying the hadronic calorimeter response,
16 part of the data was taken with the presence 17 part of the data was taken with the presence of the electromagnetic
17 crystal calorimeter in front of the hadronic 18 crystal calorimeter in front of the hadronic calorimeter, to better
18 reproduce the situation as in the real CMS ex 19 reproduce the situation as in the real CMS experiment.
19 The geometry of the simulation has been setup 20 The geometry of the simulation has been setup in such a way to allow
20 very easily, at run time (therefore without n 21 very easily, at run time (therefore without need of changing any code;
21 see below for the details) the inclusion or e 22 see below for the details) the inclusion or exclusion of the
22 electromagnetic calorimeter part. 23 electromagnetic calorimeter part.
23 Although some important aspects, for a detail 24 Although some important aspects, for a detailed comparison between
24 test-beam data and simulation, like beam prof 25 test-beam data and simulation, like beam profile, noise, and digitization,
25 have been omitted here (to avoid too many tec 26 have been omitted here (to avoid too many technical details),
26 nevertheless, this example is able to reprodu 27 nevertheless, this example is able to reproduce the main features of
27 most of the relevant observables as measured 28 most of the relevant observables as measured in the real test-beam.
28 The output of this example consists of a set << 29 The output of this example, if the AIDA or Anaphe/Lizard environment
29 and one ntuple which are stored on a ROOT fil << 30 has been properly setup (see below), consists of a set of histograms
>> 31 and one ntuple which are stored on a HBOOK file.
30 In our opinion, the most original "lesson" wh 32 In our opinion, the most original "lesson" which is offered by this
31 advanced example for the Geant4 user is to sh 33 advanced example for the Geant4 user is to show how the Geometry and
32 the Sensitive/Hit part of the simulation is t 34 the Sensitive/Hit part of the simulation is treated in a big experiment.
33 Although the details of how this is done vary 35 Although the details of how this is done vary from experiment to
34 experiment (it is worth, for instance, to com 36 experiment (it is worth, for instance, to compare with the Atlas-based
35 advanced example lAr_calorimeter), the main d 37 advanced example lAr_calorimeter), the main driving needs and goals
36 are quite general: to have consistency, but a 38 are quite general: to have consistency, but avoiding duplications
37 and couplings as much as possibile, between S 39 and couplings as much as possibile, between Simulation, Reconstruction,
38 and Visualization. Notice that the solution o 40 and Visualization. Notice that the solution offered in this example
39 by CMS could appear "overdone" for the sake o 41 by CMS could appear "overdone" for the sake of simulating only a
40 relatively simple test-beam setup; but it sho 42 relatively simple test-beam setup; but it should be kept in mind
41 that the same approach is used also for the f 43 that the same approach is used also for the full CMS detector
42 simulation, as well as for any subdetector. 44 simulation, as well as for any subdetector.
43 45
44 46
45 1. Setting up the environment variables 47 1. Setting up the environment variables
46 --------------------------------------- 48 ---------------------------------------
47 49
48 The user should first setup, as "usual", the 50 The user should first setup, as "usual", the Geant4 environmental
49 variables (e.g. the script produced by cmake) << 51 variables (in particular, the variable G4ANALYSIS_USE must be set
50 Then the specific setup for this example shou << 52 if you want to have the histograms and the ntuple).
>> 53 Then the specific setup for this example, including the AIDA/PI part
>> 54 used in the analysis, should be run:
51 55
52 > source envExample.csh in the case 56 > source envExample.csh in the case of C-shell
53 or 57 or
54 > . envExample.sh in the case 58 > . envExample.sh in the case of bash-shell
55 59
56 The analysis part is based on the native g4an << 60 The analysis part is based on AIDA/PI.
57 the output is a ROOT file. This can be change << 61 Please take a look to the web page: http://www.cern.ch/PI .
58 62
59 63
60 2. Sample run 64 2. Sample run
61 ------------- 65 -------------
62 66
63 Once the environmental variables are setup, y 67 Once the environmental variables are setup, you can get the executable
64 CompositeCalorimeter << 68 $G4WORKDIR/bin/$G4SYSTEM/CompositeCalorimeter
65 by configuring with cmake and then running th << 69 by typing "gmake" on this directory.
66 Then, you can execute it using the Geant4 mac 70 Then, you can execute it using the Geant4 macro command input file test.g4mac
67 as follows: 71 as follows:
68 72
69 > ./CompositeCalorimeter test.g4mac << 73 > $G4WORKDIR/bin/$G4SYSTEM/CompositeCalorimeter test.g4mac
70 74
71 which simulate a few events, each being a 100 << 75 which simulate 10 events, each being a 100 GeV pi- incident on the
72 electromagnetic crystal calorimeter followed 76 electromagnetic crystal calorimeter followed by the hadronic calorimeter,
73 without magnetic field. 77 without magnetic field.
74 The output is the ROOT file "ccal.root" . << 78 The output is the HBOOK file "ccal.his" , which can be seen either with
>> 79 Lizard (or any other AIDA-compliant package) or with Paw or Root.
75 See part "8. Analysis / Histogramming" below 80 See part "8. Analysis / Histogramming" below for more details on the
76 content of that file. 81 content of that file.
77 If you run instead: 82 If you run instead:
78 83
79 > ./CompositeCalorimeter << 84 > $G4WORKDIR/bin/$G4SYSTEM/CompositeCalorimeter
80 85
81 after having setup the Geant4 visualization v 86 after having setup the Geant4 visualization variables and the PATH,
82 you can visualize the geometry of the apparat 87 you can visualize the geometry of the apparatus, and also see some
83 events. Similarly, you can get a very simple 88 events. Similarly, you can get a very simple graphical user interface
84 that allows to select the particle type, its 89 that allows to select the particle type, its energy, and the number
85 of events (between a limited number of possib 90 of events (between a limited number of possibilities).
86 For more details, see part "9. Visualization 91 For more details, see part "9. Visualization / GUI".
87 92
88 93
89 3. Detector description 94 3. Detector description
90 ----------------------- 95 -----------------------
91 96
92 Let's start with a brief description of the t 97 Let's start with a brief description of the test-beam setup.
93 98
94 There are two possible configurations: 99 There are two possible configurations:
95 i) HCAL only, that is only the hadronic ca 100 i) HCAL only, that is only the hadronic calorimeter is present;
96 ii) ECAL+HCAL, that is the electromagnetic 101 ii) ECAL+HCAL, that is the electromagnetic calorimeter (ECAL)
97 is placed in front of the ha 102 is placed in front of the hadronic calorimeter.
98 ECAL is made of 23 cm long PbWO4 crystals (co 103 ECAL is made of 23 cm long PbWO4 crystals (corresponding to about
99 25.8 radiation lengths, and 1.1 interaction l 104 25.8 radiation lengths, and 1.1 interaction lengths); for the
100 test beam a 7 x 7 = 49 matrix of crystals i 105 test beam a 7 x 7 = 49 matrix of crystals is used.
101 HCAL is a sampling calorimeter, with plastic 106 HCAL is a sampling calorimeter, with plastic scintillator as sensitive
102 part and copper as absorber. 28 scintillator 107 part and copper as absorber. 28 scintillator plates were used with
103 absorber of varying thickness in between, and 108 absorber of varying thickness in between, and also varying thickness
104 and type of scintillator. More precisely: 109 and type of scintillator. More precisely:
105 --- layer 1: 2 cm of Copper 110 --- layer 1: 2 cm of Copper
106 --- layer 2 to 7: 4 cm of Copper 111 --- layer 2 to 7: 4 cm of Copper
107 --- layer 8 to 21: 6 cm of Copper 112 --- layer 8 to 21: 6 cm of Copper
108 --- layer 22 to 27: 8 cm of Copper 113 --- layer 22 to 27: 8 cm of Copper
109 For the scintillators: 2 mm passive Plastic; 114 For the scintillators: 2 mm passive Plastic; 4 mm active Plastic;
110 1 mm passive Plastic. 115 1 mm passive Plastic.
111 The total length of HCAL consists of 152 cm o 116 The total length of HCAL consists of 152 cm of Copper plus 189 mm of Plastic.
112 The dimension orthogonal to the beam directio 117 The dimension orthogonal to the beam direction is 64 cm x 64 cm.
113 The ECAL and HCAL considered here are prototy 118 The ECAL and HCAL considered here are prototypes for the Central and
114 Endcap calorimeters of the CMS detector (whic 119 Endcap calorimeters of the CMS detector (which covers the rapidity
115 region |eta| < 3.0 ; CMS has also a Forward c 120 region |eta| < 3.0 ; CMS has also a Forward calorimeter, which covers
116 the region 3.0 < |eta| < 5.0, but this part w 121 the region 3.0 < |eta| < 5.0, but this part was not considered in
117 this test-beam setup). Notice, however, that 122 this test-beam setup). Notice, however, that there are more layers
118 (28 instead of 19 in the Barrel or 18 in the 123 (28 instead of 19 in the Barrel or 18 in the Endcap) of HCAL in the
119 test-beam setup than in the real CMS detector 124 test-beam setup than in the real CMS detector, in order to study
120 energy containment. Therefore, the ECAL+HCAL 125 energy containment. Therefore, the ECAL+HCAL in the test-beam amounts
121 to more than 11 radiation lengths as for the 126 to more than 11 radiation lengths as for the real CMS detector (the
122 19 layers of the Barrel have each 6 cm of abs 127 19 layers of the Barrel have each 6 cm of absorber, whereas the
123 18 layers of the Endcap have each 6.6 cm of a 128 18 layers of the Endcap have each 6.6 cm of absorber, so that the
124 number of interaction lengths are rougly the 129 number of interaction lengths are rougly the same).
125 Five values of the magnetic field (parallel t 130 Five values of the magnetic field (parallel to the face of the scintillators)
126 have been considered in the test-beam: 0.0 , 131 have been considered in the test-beam: 0.0 , 0.375 , 0.75 , 1.50 , 3.0 Tesla.
127 132
128 In order to set the magnetic field, you have 133 In order to set the magnetic field, you have to edit the file
129 dataglobal/fmap.tb96 134 dataglobal/fmap.tb96
130 and change the first number (which appears in 135 and change the first number (which appears in the third line of
131 that file, on the first column; the unit bein 136 that file, on the first column; the unit being Tesla):
132 #. Field map 137 #. Field map
133 *DO FLDM 138 *DO FLDM
134 0.0 9 652.0 139 0.0 9 652.0
135 for example, if you want a magnetic field of 140 for example, if you want a magnetic field of 3.0 Tesla the last
136 line must be set as follows (the magnetic fie 141 line must be set as follows (the magnetic field unity is kilo Gauss).
137 30.0 9 652.0 142 30.0 9 652.0
138 143
>> 144 The default stepper in magnetic field is G4ClassicalRK4, but other
>> 145 possibilities can be selected by editing the file
>> 146 src/CCalDetectorConstruction.cc (look at the string "***STEPPER***").
>> 147
139 In order to deactivate either the ECAL or the 148 In order to deactivate either the ECAL or the HCAL, it is enough
140 to comment out the corresponding line in the 149 to comment out the corresponding line in the file g4testbeamhcal96.conf,
141 using "#" as the comment character. For insta 150 using "#" as the comment character. For instance, to have only the HCAL
142 without ECAL: 151 without ECAL:
143 "HcalTB96" "tbhcal96" 152 "HcalTB96" "tbhcal96" 1
144 #"CrystalMatrixModule" "tbhcal96xta 153 #"CrystalMatrixModule" "tbhcal96xtal" 1
145 154
146 155
147 In this test-beam setup, at the back of ECAL, 156 In this test-beam setup, at the back of ECAL, there is also some
148 material for support and readout, which has b 157 material for support and readout, which has been considered in the
149 simulation. For the HCAL, only the fibres are 158 simulation. For the HCAL, only the fibres are close to the test-beam,
150 and because they have the same composition as 159 and because they have the same composition as the scintillators
151 they are adequately represented in the simula 160 they are adequately represented in the simulation; the remaining
152 of the readout, including the photomultiplier 161 of the readout, including the photomultipliers, are in readout boxes
153 far away from the HCAL, and hence are not pre 162 far away from the HCAL, and hence are not present in the simulation.
154 163
155 Let's summarizes now the geometry description 164 Let's summarizes now the geometry description of the simulation.
156 As said in the introduction, this part is the 165 As said in the introduction, this part is the most original and
157 important of this example, but it is quite co 166 important of this example, but it is quite complex and can be fully
158 appreciated only in the context of the CMS so 167 appreciated only in the context of the CMS software framework, in
159 particular in the relation between Simulation 168 particular in the relation between Simulation, Reconstruction, and
160 Visualization. Therefore we limit ourself to 169 Visualization. Therefore we limit ourself to only few considerations,
161 pointing to the internal CMS documentation fo 170 pointing to the internal CMS documentation for more details.
162 171
163 --- In order to share the same geometrical an 172 --- In order to share the same geometrical and physical information
164 about CMS between Simulation, Reconstruct 173 about CMS between Simulation, Reconstruction, and Visualization,
165 avoiding inconsistencies, duplications, a 174 avoiding inconsistencies, duplications, and unnecessary dependecies,
166 all these information is store, once for 175 all these information is store, once for all, in common databases
167 (typically in XML format), instead of put 176 (typically in XML format), instead of putting them inside C++ classes,
168 as usually done in simpler detector descr 177 as usually done in simpler detector descriptions (in most of the
169 the Geant4 examples, novice or advanced, 178 the Geant4 examples, novice or advanced, the geometry information
170 is kept inside the concrete class which i 179 is kept inside the concrete class which inherits from
171 G4VUserDetectorConstruction). For simplic 180 G4VUserDetectorConstruction). For simplicity, in this example,
172 these "databases" are nothing more than A 181 these "databases" are nothing more than ASCII files:
173 182
174 datageom/ : tbhcal96.geom, tbhcal96hca 183 datageom/ : tbhcal96.geom, tbhcal96hcal.geom, tbhcal96xtal.geom
175 store the information abou 184 store the information about the experimental Hall,
176 the HCAL, and the ECAL, re 185 the HCAL, and the ECAL, respectively.
177 186
178 dataconf/ : g4testbeamhcal96.conf, tes 187 dataconf/ : g4testbeamhcal96.conf, testbeamhcal96.conf
179 store the information abou 188 store the information about which configuration
180 (HCAL only, or ECAL+HACL) 189 (HCAL only, or ECAL+HACL) is considered, in the
181 Simulation and Reconstruct 190 Simulation and Reconstruction, respectively.
182 191
183 dataglobal/ : fmap.tb96, material.cms, 192 dataglobal/ : fmap.tb96, material.cms, rotation.cms
184 The first one is the magne 193 The first one is the magnetic field map (how the
185 intensity of the magnetic 194 intensity of the magnetic field, in the direction
186 orthogonal to the beam dir 195 orthogonal to the beam direction, varies along
187 the beam axis). The second 196 the beam axis). The second one, material.cms,
188 keeps the full collection 197 keeps the full collection of all materials used in
189 the CMS detector (not only 198 the CMS detector (not only in the calorimeters,
190 although we are simulating 199 although we are simulating only them in this example!).
191 The third one, rotation.cm 200 The third one, rotation.cms, collects a set of useful
192 rotation parameters (angle 201 rotation parameters (angles).
193 202
194 datavis/ : tbhcal96.vis, tbhcal96hcal. 203 datavis/ : tbhcal96.vis, tbhcal96hcal.vis, tbhcal96xtal.vis
195 visualization information for, re 204 visualization information for, respectively, the
196 experimental Hall, HCAL, an 205 experimental Hall, HCAL, and ECAL.
197 206
198 --- In order to allow an high degree of flexi 207 --- In order to allow an high degree of flexibility, at the geometry
199 level the user can choose which subsystem 208 level the user can choose which subsystem of the detector setup
200 should be simulated and can activate or d 209 should be simulated and can activate or deactivate the sensitive
201 parts, subsystem by subsystem. This can b 210 parts, subsystem by subsystem. This can be done at run time,
202 by modifying one of the above database in 211 by modifying one of the above database information, without need
203 of putting the hands on the code, recompi 212 of putting the hands on the code, recompiling, etc.
204 213
205 --- There are two "parallel geometry factorie 214 --- There are two "parallel geometry factories": one described by "core"
206 classes, which are independent from the S 215 classes, which are independent from the Simulation (and therefore
207 can be used, for instance, by the Reconst 216 can be used, for instance, by the Reconstruction); and one which
208 is specific of the Simulation. In the lat 217 is specific of the Simulation. In the latter case (Geant4 side of
209 the geometry model), all the geometry fac 218 the geometry model), all the geometry factories are derived from the
210 base class CCalG4Albe. Furthermore, using 219 base class CCalG4Albe. Furthermore, using double inheritance, each
211 of them derives also from the counterpart 220 of them derives also from the counterpart in the "core" hierarchy.
212 The design of the CCalG4Able class helps 221 The design of the CCalG4Able class helps a modular approach and easy
213 interchanging at the level of subdetector 222 interchanging at the level of subdetectors, allowing a straightforward
214 transition from the simulation of the ent 223 transition from the simulation of the entire CMS detector to that of
215 just a part of it, or to a test-beam geom 224 just a part of it, or to a test-beam geometry, as indeed in this example.
216 Of course this modular, flexible, and gen 225 Of course this modular, flexible, and general approach does not come
217 for free: the price to pay here is its co 226 for free: the price to pay here is its complexity, which would be
218 otherwise unjustified if we limited ourse 227 otherwise unjustified if we limited ourself to the pure simulation
219 of a relatively simple test-beam setup. 228 of a relatively simple test-beam setup.
220 229
221 --- See "10. Classes Overview" below for a sc 230 --- See "10. Classes Overview" below for a schematic summary of the
222 various classes involved in the Geometry 231 various classes involved in the Geometry description of this example.
223 232
224 233
225 4. Physics processes 234 4. Physics processes
226 -------------------- 235 --------------------
227 236
228 The factory physics list is used, therefore t << 237 By the default, one of the ufficial High Energy Physics List for
229 is steered by the environmental variable PHYS << 238 Calorimetry, QGSC, is used in this example. However, it is
230 (Note: if this environmental variable is not << 239 very easy to use instead either LHEP or QGSP. To do so, it is
231 which is used is FTFP_BERT). << 240 enough to comment/uncomment a line in the main CompositeCalorimeter.cc :
232 << 241 for example, if you want to use LHEP instead of the default QGSC
>> 242 you have to change it as follows:
>> 243
>> 244 //***LOOKHERE*** CHOOSE THE PHYSICS LIST.
>> 245 runManager->SetUserInitialization(new LHEP); // LHEP
>> 246 // runManager->SetUserInitialization(new QGSP); // QGSP
>> 247 // runManager->SetUserInitialization(new QGSC); // QGSC
>> 248 //***endLOOKHERE***
>> 249
>> 250 Notice that, for most of the cases (and certainly also in this case
>> 251 in which we don't even take into account the beam profile, noise
>> 252 and digitization!) the faster LHEP Physics List would be good enough
>> 253 for calorimetry studies. However, we prefer to use, as default, the
>> 254 more sophisticated (but slower) QGSC Physics List for the learning
>> 255 purposes of this example.
>> 256
>> 257 Please refer to the Web page:
>> 258
>> 259 http://cmsdoc.cern.ch/~hpw/GHAD/HomePage/index.html
>> 260
>> 261 for more information on these (and others) Physics Lists.
>> 262 Please notice that, for the time being, some classes, which can be
>> 263 downloaded from the above Web page, have to be included in the
>> 264 include/ and src/ subdirectories of this example. However, hopefully
>> 265 soon, these classes will be distributed with Geant4 and therefore their
>> 266 explicit inclusion in the example will no longer be necessary.
>> 267
233 268
234 5. Particle Generator 269 5. Particle Generator
235 --------------------- 270 ---------------------
236 271
237 The 1996 test-beam has been taken with the fo 272 The 1996 test-beam has been taken with the following particles:
238 --- 225 GeV muons (for calibration) 273 --- 225 GeV muons (for calibration)
239 --- 10 to 300 GeV pions 274 --- 10 to 300 GeV pions
240 --- 10 to 300 GeV electrons 275 --- 10 to 300 GeV electrons
241 therefore the standard Geant4 Particle Gun ha 276 therefore the standard Geant4 Particle Gun has been used as primary
242 generator. Notice that, for the sake of keepi 277 generator. Notice that, for the sake of keeping the example not too
243 complicated, the proper simulation of the bea 278 complicated, the proper simulation of the beam profile and
244 beam contamination have been neglected. 279 beam contamination have been neglected.
245 280
246 281
247 6. Hits 282 6. Hits
248 ------- 283 -------
249 284
250 In CMS there are two groups of hits: Tracker- 285 In CMS there are two groups of hits: Tracker-like and Calorimeter-like.
251 Only the latter one appears in this example. 286 Only the latter one appears in this example.
252 For the same reasons, as seen for the Geometr 287 For the same reasons, as seen for the Geometry, of consistency without
253 duplication of information and unnecessary co 288 duplication of information and unnecessary coupling between Simulation,
254 Reconstruction, and Visualization, the simula 289 Reconstruction, and Visualization, the simulation calorimeter hit class,
255 CCalG4Hit, doubly inherits from the common Ge 290 CCalG4Hit, doubly inherits from the common Geant4 abstract class for
256 all hits, G4VHit, and from the "core" (i.e. s 291 all hits, G4VHit, and from the "core" (i.e. simulation independent)
257 CMS calorimeter hit class, CCalHit. 292 CMS calorimeter hit class, CCalHit.
258 A new Hit object is created 293 A new Hit object is created
259 - for each new particle entering the calori 294 - for each new particle entering the calorimeter;
260 - for each detector unit (i.e cristal or fi 295 - for each detector unit (i.e cristal or fiber or scintillator layer);
261 - for each nanosecond of the shower develop 296 - for each nanosecond of the shower development;
262 The information stored in each CCalHit object 297 The information stored in each CCalHit object is the following:
263 - Entry : local coordinates of the entranc 298 - Entry : local coordinates of the entrance point of the particle
264 in the unit where the shower sta 299 in the unit where the shower starts;
265 - the TrackID : Identification number of t 300 - the TrackID : Identification number of the incident particle;
266 - the IncidentEnergy : kinetic energy of t 301 - the IncidentEnergy : kinetic energy of that incident particle;
267 - the UnitID : the identification number of 302 - the UnitID : the identification number of the detector unit
268 (crystal, or fiber, or scint 303 (crystal, or fiber, or scintillator layer);
269 - the TimeSlice : the time interval, in nan 304 - the TimeSlice : the time interval, in nanoseconds, in which the
270 hit has been created; 305 hit has been created;
271 - the EnergyDeposit : the energy deposit in 306 - the EnergyDeposit : the energy deposit in this hit.
272 Notice that all hit objects created for a giv 307 Notice that all hit objects created for a given shower have the same
273 values for the first three pieces of informat 308 values for the first three pieces of information.
274 309
275 310
276 No Noise and Digitization 311 No Noise and Digitization
277 -------------------------- 312 --------------------------
278 313
279 In order to keep the complexity of this examp 314 In order to keep the complexity of this example to a reasonable
280 level, both noise and digitization effects ha 315 level, both noise and digitization effects have not been included.
281 316
282 317
283 7. User Actions 318 7. User Actions
284 ---------------- 319 ----------------
285 320
286 In this example. there have been used the fol 321 In this example. there have been used the following User Actions:
287 322
288 --- G4UserRunAction (the derived, concrete cl 323 --- G4UserRunAction (the derived, concrete class is CCalRunAction):
289 it is used to invoke the Analysis object 324 it is used to invoke the Analysis object at the beginning of
290 the Run, to instantiate it and passing it 325 the Run, to instantiate it and passing it the Run number, and
291 at the end of the Run, to inform it that 326 at the end of the Run, to inform it that the Run is finished
292 and therefore the histograms, ntuples, et 327 and therefore the histograms, ntuples, etc. must be closed.
293 328
294 --- G4UserEventAction (the derived, concrete 329 --- G4UserEventAction (the derived, concrete class is CCalEndOfEventAction):
295 it is used to examine, at the end of the 330 it is used to examine, at the end of the Event, all collected
296 (calorimeter) hits, extract the various o 331 (calorimeter) hits, extract the various observables which are
297 interesting (to the goal of understanding 332 interesting (to the goal of understanding things like: the effect
298 of magnetic field on scintiallator; choic 333 of magnetic field on scintiallator; choice of the absorber
299 thickness by optimizing resolution versus 334 thickness by optimizing resolution versus containment; impact of
300 the absorber depth in the energy caontain 335 the absorber depth in the energy caontainment; electromagnetic
301 calorimeter contribution in the electron 336 calorimeter contribution in the electron - pion separation; etc.)
302 and finally call the analysis object to s 337 and finally call the analysis object to store such selected
303 information on histograms and/or in the n 338 information on histograms and/or in the ntuple.
304 The name of the class "CCalEndOfEventActi 339 The name of the class "CCalEndOfEventAction" is motivated by the
305 fact that at the beginning of the Event n 340 fact that at the beginning of the Event nothing is done.
306 341
307 --- G4UserSteppingAction (the derived, concre 342 --- G4UserSteppingAction (the derived, concrete class is CCalSteppingAction):
308 it is used to extract some "unphysical" i 343 it is used to extract some "unphysical" information (that is not
309 experimentally measurable, although inter 344 experimentally measurable, although interesting for a better
310 understanding of the shower development), 345 understanding of the shower development), namely the lateral profile
311 and the deposit as a function of the time 346 and the deposit as a function of the time (see "8.Analysis/Histogramming
312 for more details"), which is available on 347 for more details"), which is available only from simulation, and then,
313 at the end of Event, the analysis object 348 at the end of Event, the analysis object is invoked to store such
314 information on histograms. 349 information on histograms.
315 Please notice that the stepping action is 350 Please notice that the stepping action is not used to create hits.
316 351
317 --- G4UserStackingAction (the derived, concre 352 --- G4UserStackingAction (the derived, concrete class is CCalStackingAction):
318 it is used to ensure that the same track 353 it is used to ensure that the same track ID of the particle
319 originating a shower appears in all hits 354 originating a shower appears in all hits (calorimeter hit objects
320 of class CCalHit) of the shower, in any c 355 of class CCalHit) of the shower, in any calorimeter part.
321 356
322 357
323 8. Analysis / Histogramming 358 8. Analysis / Histogramming
324 ---------------------------- 359 ----------------------------
325 360
326 The analysis part of CompositeCalorimeter is 361 The analysis part of CompositeCalorimeter is kept in class CCalAnalysis,
327 and is based on the g4tool interfaces. << 362 and is based on the AIDA interfaces and their implementation in PI.
>> 363 Please take a look to the web page: http://www.cern.ch/PI .
328 Both the histograms and the ntuple are saved 364 Both the histograms and the ntuple are saved at the end of the run in the
329 ROOT file "ccal.root" (default: this can be c << 365 HBOOK file "ccal.his". You can than analyze offline the contents of such
330 formats supported by the g4analysis tools). << 366 a file, using Lizard (or any other AIDA-compliant package) or with
331 Please note that in a multiple run session, t << 367 Paw or Root. Please note that in a multiple run session, the last run
332 the output file. << 368 always override the HBOOK file.
333 What the histograms and the variables of the 369 What the histograms and the variables of the ntuple represent is
334 explained below: 370 explained below:
335 371
336 Histograms h100 - h127 : energy deposit (in << 372 Histograms 100 - 127 : energy deposit (in GeV) in the sensitive part
337 (plastic scintillato 373 (plastic scintillator layer) of one Hadronic
338 calorimeter module ( 374 calorimeter module (there are 28 modules, numbered
339 from 0 to 27, and th 375 from 0 to 27, and the corresponding histogram has
340 ID = 100 + number of 376 ID = 100 + number of module).
341 Ntuple variables hcal0 - hcal27 : provide t 377 Ntuple variables hcal0 - hcal27 : provide the same information.
342 378
343 Histograms h200 - h248 : energy deposit (in << 379 Histograms 200 - 248 : energy deposit (in GeV) in one crystal
344 electromagnetic towe 380 electromagnetic towers (there are a matrix of
345 7 x 7 = 49 towers, n 381 7 x 7 = 49 towers, numbered from 0 to 48, and
346 the corresponding hi 382 the corresponding histogram has
347 ID = 200 + number of 383 ID = 200 + number of tower).
348 Ntuple variables ecal0 - ecal48 : provide t 384 Ntuple variables ecal0 - ecal48 : provide the same information.
349 385
350 Histograms h300 - h339 : total energy depos << 386 Histograms 300 - 339 : total energy deposit (in GeV) in any
351 electromagnetic crys 387 electromagnetic crystal tower or hadronic module
352 (either in a sensiti 388 (either in a sensitive or insensitive layer)
353 in one of the 40 nan 389 in one of the 40 nanosecond time slices: in other
354 words, histogram 30 390 words, histogram 300+I , where I = 0 - 39,
355 contains the total d 391 contains the total deposit energy between
356 I and I+1 nanosecond 392 I and I+1 nanoseconds after the "collision".
357 (Notice that the tim 393 (Notice that the time window considered,
358 40 nanoseconds, is 394 40 nanoseconds, is larger than the LHC
359 bunch-crossing of 2 395 bunch-crossing of 25 nanoseconds.)
360 396
361 Histograms h400 - h469 : energy profile (in << 397 Histograms 400 - 469 : energy profile (in GeV), summed over all layers
362 sensitive (plastic s 398 sensitive (plastic scintillator) and insensitive
363 (copper absorber), a 399 (copper absorber), as a function of the radial
364 distance (in centime 400 distance (in centimeter) from the beam axis
365 ( ID histo = 400 + r 401 ( ID histo = 400 + radial distance in cm ).
366 402
367 Histogram h4000 : total energy deposit (in << 403 Histogram 4000 : total energy deposit (in GeV) in the sensitive parts
368 of either the electromagne 404 of either the electromagnetic or hadronic calorimeters.
369 Ntuple variable edep provides the same info 405 Ntuple variable edep provides the same information.
370 406
371 Other ntuple variables are the following: 407 Other ntuple variables are the following:
372 --- elab : energy (in GeV) of the inci 408 --- elab : energy (in GeV) of the incident particle.
373 --- xpos, ypos, zpos : position (in mm 409 --- xpos, ypos, zpos : position (in mm) from where the projectile
374 has been shot. 410 has been shot.
375 --- edec, edhc : total energy deposit 411 --- edec, edhc : total energy deposit (in GeV) in the sensitive
376 parts of, respectivel 412 parts of, respectively, the electromagnetic
377 and hadronic calorime 413 and hadronic calorimeters. Notice that their
378 sum edec+edhc coinc 414 sum edec+edhc coincides with edep
379 415
380 Notice that lateral profile (400-469) and ti 416 Notice that lateral profile (400-469) and time-slice (300-339)
381 histograms show purely Monte Carlo quantitie 417 histograms show purely Monte Carlo quantities, which cannot be
382 experimentally measured. 418 experimentally measured.
383 Please be careful that the range of the hist 419 Please be careful that the range of the histograms has been chosen
384 in such a way to contain most of the entries 420 in such a way to contain most of the entries, but only few histograms
385 fill a large fraction of that range, whereas 421 fill a large fraction of that range, whereas the remaining majority
386 fill only the first few bins (corresponding 422 fill only the first few bins (corresponding to lower energy), and,
387 therefore, when plotted they look almost emp 423 therefore, when plotted they look almost empty, but they are not,
388 and the results are sensible. We suggest to 424 and the results are sensible. We suggest to plot the ntuple's variables,
389 rather than the histograms, when the same in 425 rather than the histograms, when the same information is available
390 from the ntuple. 426 from the ntuple.
391 427
392 428
393 9. Visualization / GUI 429 9. Visualization / GUI
394 ----------------------- 430 -----------------------
395 431
396 If you setup one of the following Geant4 envi 432 If you setup one of the following Geant4 environmental variables:
397 G4VIS_USE_DAWN 433 G4VIS_USE_DAWN
398 G4VIS_USE_VRML 434 G4VIS_USE_VRML
399 G4VIS_USE_OPENGLX 435 G4VIS_USE_OPENGLX
400 which correspond to the use of DAWN, VRML, an 436 which correspond to the use of DAWN, VRML, and OPENGLX, respectively,
401 as visualization engine of Geant4, and set pr 437 as visualization engine of Geant4, and set properly the corresponding
402 PATH as well, it is then possible to visual 438 PATH as well, it is then possible to visualize the detector and also
403 some events. 439 some events.
404 To do so, you have to run 440 To do so, you have to run
405 > ./CompositeCalorimeter << 441 > $G4WORKDIR/bin/$G4SYSTEM/CompositeCalorimeter
406 without input file: you then see the detector 442 without input file: you then see the detector; after that,
407 you can select the particle gun and its energ 443 you can select the particle gun and its energy, in the
408 case you want something different from the th 444 case you want something different from the the default
409 (which is a 100 GeV pi-), for example: 445 (which is a 100 GeV pi-), for example:
410 Idle> /gun/particle e- 446 Idle> /gun/particle e-
411 Idle> /gun/energy 200 GeV 447 Idle> /gun/energy 200 GeV
412 and then run some events, for example: 448 and then run some events, for example:
413 Idle> /run/beamOn 3 449 Idle> /run/beamOn 3
414 450
>> 451 Notice that, by default, OGLIX is used for the visualization,
>> 452 because it is quite fast and it does not produce any files in
>> 453 output. However, you can always choose something else, for example
>> 454 VRML2FILE or DAWNFILE, either interactively as follows:
>> 455 Idle> /vis/open DAWNFILE
>> 456 or by changing the default, by editing the file (main program)
>> 457 CompositeCalorimeter.cc and comment/uncomment the lines
>> 458 in such a way to have, at the end:
>> 459 visCommand = "/vis/open DAWNFILE";
>> 460 // visCommand = "/vis/open VRML2FILE";
>> 461 // visCommand = "/vis/open OGLIX";
>> 462
415 The tracks that are shown include both charge 463 The tracks that are shown include both charged and neutral particles
416 of any momentum: if you want instead only cha 464 of any momentum: if you want instead only charged, or only neutral,
417 then you have simply to edit src/CCalEndOfEv 465 then you have simply to edit src/CCalEndOfEventAction.cc
418 at the end of the method EndOfEventAction a 466 at the end of the method EndOfEventAction and uncomment the line
419 where the condition on the charge is made (it 467 where the condition on the charge is made (it should then be
420 straighforward to eventual add some other con 468 straighforward to eventual add some other conditions, for example
421 if you want to see only those particles that 469 if you want to see only those particles that satisfy certain
422 kinematic conditions). 470 kinematic conditions).
423 471
424 Rather than to specify "by hand" the type of 472 Rather than to specify "by hand" the type of particle gun,
425 its energy, and the number of events, it is p 473 its energy, and the number of events, it is possible to have
426 a very simple GUI (graphical user interface) 474 a very simple GUI (graphical user interface) from which to make
427 such choices, between a limited set of possib 475 such choices, between a limited set of possibilities, via menus.
428 Such GUI is based on Motif XmCommand widget, 476 Such GUI is based on Motif XmCommand widget, but it would be
429 straightforward, eventually, to make the nece 477 straightforward, eventually, to make the necessary changes
430 in order to use a different one. 478 in order to use a different one.
431 The only thing you need to do to get the GUI 479 The only thing you need to do to get the GUI is to setup
432 the following Geant4 environmental variables: 480 the following Geant4 environmental variables:
433 G4UI_BUILD_XM_SESSION=1 481 G4UI_BUILD_XM_SESSION=1
434 G4UI_USE_XM=1 482 G4UI_USE_XM=1
435 Then, if you run the executable without speci 483 Then, if you run the executable without specifying a macro file
436 (like test.g4mac): 484 (like test.g4mac):
437 > $G4WORKDIR/bin/$G4SYSTEM/CompositeCalo 485 > $G4WORKDIR/bin/$G4SYSTEM/CompositeCalorimeter
438 a window automatically pops out, with the men 486 a window automatically pops out, with the menus where you
439 can make your selection of particle type, ene 487 can make your selection of particle type, energy, and number
440 of events to be run. 488 of events to be run.
441 489
442 490
443 10. Classes Overview 491 10. Classes Overview
444 --------------------- 492 ---------------------
445 493
446 This is a schematic overview of the classes d 494 This is a schematic overview of the classes defined in this example:
447 495
448 CCalPrimaryGeneratorAction 496 CCalPrimaryGeneratorAction
449 CCalPrimaryGeneratorMessenger 497 CCalPrimaryGeneratorMessenger
450 User action for primaries generator. 498 User action for primaries generator.
451 499
452 CCalDetectorConstruction 500 CCalDetectorConstruction
453 CCalAMaterial 501 CCalAMaterial
454 CCalDataSet 502 CCalDataSet
455 CCalDetector 503 CCalDetector
456 CCalEcal 504 CCalEcal
457 CCalEcalOrganization 505 CCalEcalOrganization
458 CCalG4Able 506 CCalG4Able
459 CCalG4Ecal 507 CCalG4Ecal
460 CCalG4Hall 508 CCalG4Hall
461 CCalG4Hcal 509 CCalG4Hcal
462 CCalGeometryConfiguration 510 CCalGeometryConfiguration
463 CCalHall 511 CCalHall
464 CCalHcal 512 CCalHcal
465 CCalHcalOrganization 513 CCalHcalOrganization
466 CCalMagneticField 514 CCalMagneticField
467 CCalMaterial 515 CCalMaterial
468 CCalMaterialFactory 516 CCalMaterialFactory
469 CCalRotationMatrixFactory 517 CCalRotationMatrixFactory
470 CCalVOrganization 518 CCalVOrganization
471 CCalVisManager 519 CCalVisManager
472 CCalVisualisable 520 CCalVisualisable
473 CCaloOrganization 521 CCaloOrganization
474 CCalutils 522 CCalutils
475 Geometry and material definitions for the de 523 Geometry and material definitions for the detector.
476 Notice in particular that: 524 Notice in particular that:
477 CCalHall, CCalEcal, CCalHcal derive 525 CCalHall, CCalEcal, CCalHcal derive from CCalDetector;
478 CCalG4Hall, CCalG4Ecal, CCalG4Hcal d 526 CCalG4Hall, CCalG4Ecal, CCalG4Hcal derive from the above
479 corresponding classes and from CC 527 corresponding classes and from CCalG4Able;
480 CCalEcalOrganization, CCalHcalOrgani 528 CCalEcalOrganization, CCalHcalOrganization derive from
481 CCalVOrganization : each sensitiv 529 CCalVOrganization : each sensitive cell has an unique
482 number for detector organization 530 number for detector organization (this is a software
483 ID not an hardware/electronic one 531 ID not an hardware/electronic one).
484 532
485 CCalHit 533 CCalHit
486 CCalG4Hit 534 CCalG4Hit
487 CCalG4HitCollection 535 CCalG4HitCollection
488 CCalSDList 536 CCalSDList
489 CCalSensAssign 537 CCalSensAssign
490 CCalSensitiveConfiguration 538 CCalSensitiveConfiguration
491 CCalSensitiveDetectors 539 CCalSensitiveDetectors
492 CCaloSD 540 CCaloSD
493 Hit and Sensitive Detectors. 541 Hit and Sensitive Detectors.
494 Notice in particular that: 542 Notice in particular that:
495 CCalG4Hit derives from G4VHit and CC 543 CCalG4Hit derives from G4VHit and CCalHit;
496 CCaloSD derives from G4VSensitiveDet 544 CCaloSD derives from G4VSensitiveDetector.
497 545
498 CCalActionInitializer <<
499 User-action initialization. <<
500 <<
501 CCalAnalysis 546 CCalAnalysis
502 Analysis manager class. << 547 Analysis manager class which uses Anaphe.
503 548
504 CCalRunAction 549 CCalRunAction
505 User run action class. 550 User run action class.
506 551
507 CCalEndOfEventAction 552 CCalEndOfEventAction
508 User event action class. 553 User event action class.
509 554
510 CCalStackingAction 555 CCalStackingAction
511 User Stacking action class. 556 User Stacking action class.
512 557
513 CCalSteppingAction 558 CCalSteppingAction
514 User Stepping action class. 559 User Stepping action class.
515 560