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1 | /////////////////////////////////////////////////////////////////////////////// | |
2 | // // | |
3 | // Transition Radiation Detector version 2 -- detailed simulation // | |
4 | // // | |
5 | //Begin_Html | |
6 | /* | |
7 | <img src="gif/AliTRDv2Class.gif"> | |
8 | */ | |
9 | //End_Html | |
10 | // // | |
11 | // // | |
12 | /////////////////////////////////////////////////////////////////////////////// | |
13 | ||
14 | #include <TMath.h> | |
15 | #include <TRandom.h> | |
16 | #include <TVector.h> | |
17 | #include <TGeometry.h> | |
18 | #include <TNode.h> | |
19 | #include <TPGON.h> | |
20 | ||
21 | #include "GParticle.h" | |
22 | #include "AliTRDv2.h" | |
23 | #include "AliRun.h" | |
24 | #include "AliConst.h" | |
25 | #include "AliMC.h" | |
26 | ||
27 | ClassImp(AliTRDv2) | |
28 | ||
29 | //_____________________________________________________________________________ | |
30 | AliTRDv2::AliTRDv2(const char *name, const char *title) | |
31 | :AliTRD(name, title) | |
32 | { | |
33 | // | |
34 | // Standard constructor for Transition Radiation Detector version 2 | |
35 | // | |
36 | fIdSenO1 = fIdSenO2 = fIdSenO3 = fIdSenO4 = fIdSenO5 = fIdSenO6 = 0; | |
37 | fIdSenI1 = fIdSenI2 = fIdSenI3 = fIdSenI4 = fIdSenI5 = fIdSenI6 = 0; | |
38 | SetBufferSize(128000); | |
39 | } | |
40 | ||
41 | //_____________________________________________________________________________ | |
42 | void AliTRDv2::CreateGeometry() | |
43 | { | |
44 | // | |
45 | // Create geometry for the Transition Radiation Detector version 2 | |
46 | // This version covers the full azimuth. | |
47 | // | |
48 | //Begin_Html | |
49 | /* | |
50 | <img src="gif/AliTRDv2.gif"> | |
51 | */ | |
52 | //End_Html | |
53 | //Begin_Html | |
54 | /* | |
55 | <img src="gif/AliTRDv2Tree.gif"> | |
56 | */ | |
57 | //End_Html | |
58 | ||
59 | ||
60 | // --- Name Conventions : | |
61 | ||
62 | // The mother volume and the support structure | |
63 | // TRD --> Mother TRD volume (Air) | |
64 | // UTRS --> The sectors of the detector (Air) | |
65 | // UTSP --> The aluminum part of the support structure (Al) | |
66 | // UTII(O) --> The inner parts of the support structure (Air) | |
67 | ||
68 | // The chambers | |
69 | // UCI1-6 --> The frame of the inner chambers (C) | |
70 | // UCO1-6 --> The frame of the outer chambers (C) | |
71 | // UII1-6 --> The inner part of the inner chambers (Air) | |
72 | // UIO1-6 --> The inner part of the outer chambers (Air) | |
73 | ||
74 | // The layers inside a chamber | |
75 | // UT1I(O) --> Radiator layer (CO2) | |
76 | // UT2I(O) --> Polyethylene layer (PE) | |
77 | // UT3I(O) --> Mylar layer (Mylar) | |
78 | // UXI1-6 --> Xe/C02 layer in the inner chambers (Xe/C02) | |
79 | // UXO1-6 --> Xe/C02 layer in the outer chambers (Xe/C02) | |
80 | // UT5I(O) --> Cu layer (pads/sensitive) (Cu) | |
81 | // UT6I(O) --> Kapton layer (Kapton) | |
82 | // UT7I(O) --> NOMEX layer (C) | |
83 | // UT8I(O) --> Readout layer (Al) | |
84 | ||
85 | ||
86 | // --- Contains geometry information | |
87 | ||
88 | // --- Number of sectors in the full detector | |
89 | // --- Number of modules in each sector | |
90 | // --- z-Coordinates of the TRD-frame | |
91 | // --- r-Coordinates of the TRD-frame | |
92 | // --- Thickness of the aluminium of the support frame | |
93 | // --- Thickness of the interior of the support frame | |
94 | // --- Thickness of the carbon chamber frame | |
95 | // --- Thickness and z-position of the PE-layer in the radiator | |
96 | // --- Thickness and z-position of the radiator | |
97 | // --- Thickness and z-position of the mylar-layer | |
98 | // --- Thickness and z-position of the Xe/C02-layer | |
99 | // --- Thickness and z-position of the Cu-layer (Pads) | |
100 | // --- Thickness and z-position of the kapton-layer | |
101 | // --- Thickness and z-position of the NOMEX-layer | |
102 | // Simple C-layer for the time being | |
103 | // --- Thickness and z-position of the readout-layer | |
104 | // --- Parameter for the arrays | |
105 | // --- Number of different chambers | |
106 | // --- Number of rotation matrices | |
107 | ||
108 | AliMC* pMC = AliMC::GetMC(); | |
109 | ||
110 | Float_t xpos, ypos, zpos; | |
111 | Int_t icham; | |
112 | Int_t idmat[2]; | |
113 | Float_t widma, widmi; | |
114 | Float_t lendifc, widdifc, heightc; | |
115 | Float_t par_ic[3], par_oc[3], par_mo[10], par_sp[4], par_ch[3]; | |
116 | ||
117 | Int_t *idtmed = gAlice->Idtmed(); | |
118 | ||
119 | //************************************************************************ | |
120 | ||
121 | // Definition of Volumes | |
122 | ||
123 | //************************************************************************ | |
124 | ||
125 | const Int_t ncham = 6; //Number of different chambers | |
126 | ||
127 | widmi = rmin*TMath::Sin(kPI/nsect); | |
128 | widma = rmax*TMath::Sin(kPI/nsect); | |
129 | // --- Some parameter for the chambers | |
130 | lendifc = (zmax1-zmax2)/nmodul; | |
131 | heightc = (rmax-rmin)/nmodul; | |
132 | widdifc = (widma - widmi)/nmodul; | |
133 | // --- Definition of the Mother volume for the TRD (Air) | |
134 | par_mo[0] = 0.; | |
135 | par_mo[1] = 360.; | |
136 | par_mo[2] = nsect; | |
137 | par_mo[3] = 2.; | |
138 | par_mo[4] = -zmax1; | |
139 | par_mo[5] = rmin; | |
140 | par_mo[6] = rmax; | |
141 | par_mo[7] = zmax1; | |
142 | par_mo[8] = rmin; | |
143 | par_mo[9] = rmax; | |
144 | pMC->Gsvolu("TRD ", "PGON", idtmed[1301], par_mo, 10); | |
145 | // --- Divide the mother volume into sectors | |
146 | pMC->Gsdvn("UTRS", "TRD ", nsect, 2); | |
147 | // --- Definition of the aluminum part of the support structure (Al) | |
148 | par_sp[0] = widmi - inframe/2; | |
149 | par_sp[1] = widma - inframe/2; | |
150 | par_sp[2] = zmax1/2; | |
151 | par_sp[3] = (rmax-rmin)/2; | |
152 | pMC->Gsvolu("UTSP", "TRD1", idtmed[1300], par_sp, 4); | |
153 | // --- Definition of the inner part of the support structure (Air) | |
154 | par_sp[0] = widmi - inframe/2 - alfram1/2; | |
155 | par_sp[1] = widma - inframe/2 - alfram1/2; | |
156 | par_sp[2] = zmax1/4 -alfram2/2; | |
157 | par_sp[3] = (rmax-rmin)/2; | |
158 | pMC->Gsvolu("UTII", "TRD1", idtmed[1301], par_sp, 4); | |
159 | pMC->Gsvolu("UTIO", "TRD1", idtmed[1301], par_sp, 4); | |
160 | // --- Definition of the chambers | |
161 | char ctagc[5], ctagi[5], ctagx[5]; | |
162 | for (icham = 1; icham <= ncham; ++icham) { | |
163 | // --- Carbon frame of the inner chambers (C) | |
164 | par_ch[0] = widmi + (icham-1) * widdifc - (inframe+alfram1)/2; | |
165 | par_ch[1] = zmax1/4 -alfram2/2; | |
166 | par_ch[2] = heightc/2.; | |
167 | sprintf(ctagc,"UCI%1d",icham); | |
168 | pMC->Gsvolu(ctagc, "BOX ", idtmed[1306], par_ch, 3); | |
169 | // --- Inner part of the inner chambers (Air) | |
170 | par_ch[0] -= ccframe; | |
171 | par_ch[1] -= ccframe; | |
172 | sprintf(ctagi,"UII%1d",icham); | |
173 | pMC->Gsvolu(ctagi, "BOX ", idtmed[1301], par_ch, 3); | |
174 | // --- Carbon frame of the outer chambers (C) | |
175 | par_ch[0] = widmi + (icham - 1) * widdifc - 2.; | |
176 | par_ch[1] = (icham - 6) * lendifc / 2. + zmax1/4 -alfram2/2; | |
177 | par_ch[2] = heightc / 2.; | |
178 | sprintf(ctagc,"UCO%1d",icham); | |
179 | pMC->Gsvolu(ctagc, "BOX ", idtmed[1306], par_ch, 3); | |
180 | // --- Inner part of the outer chambers (Air) | |
181 | par_ch[0] -= ccframe; | |
182 | par_ch[1] -= ccframe; | |
183 | sprintf(ctagi,"UIO%1d",icham); | |
184 | pMC->Gsvolu(ctagi, "BOX ", idtmed[1301], par_ch, 3); | |
185 | } | |
186 | // --- Definition of the layers in each inner chamber | |
187 | par_ic[0] = -1.; | |
188 | par_ic[1] = -1.; | |
189 | // --- Radiator layer | |
190 | par_ic[2] = rathick/2;; | |
191 | pMC->Gsvolu("UT1I", "BOX ", idtmed[1311], par_ic, 3); | |
192 | // --- Polyethylene layer | |
193 | par_ic[2] = pethick/2; | |
194 | pMC->Gsvolu("UT2I", "BOX ", idtmed[1302], par_ic, 3); | |
195 | // --- Mylar layer | |
196 | par_ic[2] = mythick/2; | |
197 | pMC->Gsvolu("UT3I", "BOX ", idtmed[1307], par_ic, 3); | |
198 | // --- Xe/CO2 layer | |
199 | par_ic[2] = 1.8; | |
200 | for (icham = 1; icham <= 6; ++icham) { | |
201 | sprintf(ctagx,"UXI%1d",icham); | |
202 | pMC->Gsvolu(ctagx, "BOX ", idtmed[1308], par_ic, 3); | |
203 | } | |
204 | // --- Cu layer | |
205 | par_ic[2] = cuthick/2; | |
206 | pMC->Gsvolu("UT5I", "BOX ", idtmed[1304], par_ic, 3); | |
207 | // --- Kapton layer | |
208 | par_ic[2] = kathick/2; | |
209 | pMC->Gsvolu("UT6I", "BOX ", idtmed[1310], par_ic, 3); | |
210 | // --- NOMEX layer | |
211 | par_ic[2] = nothick/2; | |
212 | pMC->Gsvolu("UT7I", "BOX ", idtmed[1309], par_ic, 3); | |
213 | // --- Read out layer | |
214 | par_ic[2] = rothick/2; | |
215 | pMC->Gsvolu("UT8I", "BOX ", idtmed[1305], par_ic, 3); | |
216 | // --- Definition of the layers in each outer chamber | |
217 | par_oc[0] = -1.; | |
218 | par_oc[1] = -1.; | |
219 | // --- Radiator layer | |
220 | par_oc[2] = rathick/2;; | |
221 | pMC->Gsvolu("UT1O", "BOX ", idtmed[1311], par_oc, 3); | |
222 | // --- Polyethylene layer | |
223 | par_oc[2] = pethick/2; | |
224 | pMC->Gsvolu("UT2O", "BOX ", idtmed[1302], par_oc, 3); | |
225 | // --- Mylar layer | |
226 | par_oc[2] = mythick/2; | |
227 | pMC->Gsvolu("UT3O", "BOX ", idtmed[1307], par_oc, 3); | |
228 | // --- Xe/CO2 layer | |
229 | par_oc[2] = xethick/2; | |
230 | for (icham = 1; icham <= ncham; ++icham) { | |
231 | sprintf(ctagx,"UXO%1d",icham); | |
232 | pMC->Gsvolu(ctagx, "BOX ", idtmed[1308], par_oc, 3); | |
233 | } | |
234 | // --- Cu layer | |
235 | par_oc[2] = cuthick/2; | |
236 | pMC->Gsvolu("UT5O", "BOX ", idtmed[1304], par_oc, 3); | |
237 | // --- Kapton layer | |
238 | par_oc[2] = kathick/2; | |
239 | pMC->Gsvolu("UT6O", "BOX ", idtmed[1310], par_oc, 3); | |
240 | // --- NOMEX layer | |
241 | par_oc[2] = nothick/2; | |
242 | pMC->Gsvolu("UT7O", "BOX ", idtmed[1309], par_oc, 3); | |
243 | // --- Read out layer | |
244 | par_oc[2] = rothick/2; | |
245 | pMC->Gsvolu("UT8O", "BOX ", idtmed[1305], par_oc, 3); | |
246 | //************************************************************************* | |
247 | ||
248 | // Positioning of Volumes | |
249 | ||
250 | //************************************************************************ | |
251 | // --- The rotation matrices | |
252 | AliMatrix(idmat[0], 90., 90., 180., 0., 90., 0.); | |
253 | AliMatrix(idmat[1], 90., 90., 0., 0., 90., 0.); | |
254 | // --- Position of the layers in a chamber | |
255 | for (icham = 1; icham <= ncham; ++icham) { | |
256 | // --- The inner chambers | |
257 | sprintf(ctagi,"UII%1d",icham); | |
258 | sprintf(ctagx,"UXI%1d",icham); | |
259 | pMC->Gspos("UT8I", icham, ctagi, 0., 0., rozpos, 0, "ONLY"); | |
260 | pMC->Gspos("UT7I", icham, ctagi, 0., 0., nozpos, 0, "ONLY"); | |
261 | pMC->Gspos("UT6I", icham, ctagi, 0., 0., kazpos, 0, "ONLY"); | |
262 | pMC->Gspos("UT5I", icham, ctagi, 0., 0., cuzpos, 0, "ONLY"); | |
263 | pMC->Gspos(ctagx, 1, ctagi, 0., 0., xezpos, 0, "ONLY"); | |
264 | pMC->Gspos("UT3I", icham, ctagi, 0., 0., myzpos, 0, "ONLY"); | |
265 | pMC->Gspos("UT1I", icham, ctagi, 0., 0., razpos, 0, "ONLY"); | |
266 | // --- The outer chambers | |
267 | sprintf(ctagi,"UIO%d",icham); | |
268 | sprintf(ctagx,"UXO%d",icham); | |
269 | pMC->Gspos("UT8O", icham, ctagi, 0., 0., rozpos, 0, "ONLY"); | |
270 | pMC->Gspos("UT7O", icham, ctagi, 0., 0., nozpos, 0, "ONLY"); | |
271 | pMC->Gspos("UT6O", icham, ctagi, 0., 0., kazpos, 0, "ONLY"); | |
272 | pMC->Gspos("UT5O", icham, ctagi, 0., 0., cuzpos, 0, "ONLY"); | |
273 | pMC->Gspos(ctagx, 1, ctagi, 0., 0., xezpos, 0, "ONLY"); | |
274 | pMC->Gspos("UT3O", icham, ctagi, 0., 0., myzpos, 0, "ONLY"); | |
275 | pMC->Gspos("UT1O", icham, ctagi, 0., 0., razpos, 0, "ONLY"); | |
276 | } | |
277 | pMC->Gspos("UT2I", 1, "UT1I", 0., 0., 0., 0, "ONLY"); | |
278 | pMC->Gspos("UT2O", 1, "UT1O", 0., 0., 0., 0, "ONLY"); | |
279 | // --- Position of the inner part of the chambers in the carbon-frames | |
280 | for (icham = 1; icham <= ncham; ++icham) { | |
281 | // --- The inner chambers | |
282 | sprintf(ctagi,"UII%1d",icham); | |
283 | sprintf(ctagc,"UCI%1d",icham); | |
284 | pMC->Gspos(ctagi, 1, ctagc, 0., 0., 0., 0, "ONLY"); | |
285 | // --- The outer chambers | |
286 | sprintf(ctagi,"UIO%1d",icham); | |
287 | sprintf(ctagc,"UCO%1d",icham); | |
288 | pMC->Gspos(ctagi, 1, ctagc, 0., 0., 0., 0, "ONLY"); | |
289 | } | |
290 | // --- Position of the chambers in the full TRD-setup | |
291 | for (icham = 1; icham <= ncham; ++icham) { | |
292 | // --- The inner chambers | |
293 | xpos = 0.; | |
294 | ypos = 0.; | |
295 | zpos = (icham - .5) * heightc - (rmax-rmin)/2; | |
296 | sprintf(ctagc,"UCI%1d",icham); | |
297 | pMC->Gspos(ctagc, 1, "UTII", xpos, ypos, zpos, 0, "ONLY"); | |
298 | // --- The outer chambers | |
299 | xpos = 0.; | |
300 | ypos = 0. - (icham - 6) * lendifc / 2.; | |
301 | zpos = (icham - .5) * heightc - (rmax-rmin)/2; | |
302 | sprintf(ctagc,"UCO%1d",icham); | |
303 | pMC->Gspos(ctagc, 1, "UTIO", xpos, ypos, zpos, 0, "ONLY"); | |
304 | } | |
305 | // --- Position of the inner parts of the support frame | |
306 | xpos = 0.; | |
307 | ypos = zmax1/4; | |
308 | zpos = 0.; | |
309 | pMC->Gspos("UTIO", 1, "UTSP", xpos,-ypos, zpos, 0, "ONLY"); | |
310 | pMC->Gspos("UTII", 1, "UTSP", xpos, ypos, zpos, 0, "ONLY"); | |
311 | // --- Position of the support frame in the TRD-sectors | |
312 | xpos = (rmax+rmin)/2; | |
313 | ypos = 0.; | |
314 | zpos = zmax1/2; | |
315 | pMC->Gspos("UTSP", 1, "UTRS", xpos, ypos, zpos, idmat[0], "ONLY"); | |
316 | pMC->Gspos("UTSP", 2, "UTRS", xpos, ypos,-zpos, idmat[1], "ONLY"); | |
317 | // --- Position of TRD mother volume in ALICE experiment | |
318 | pMC->Gspos("TRD ", 1, "ALIC", 0., 0., 0., 0, "ONLY"); | |
319 | } | |
320 | ||
321 | //_____________________________________________________________________________ | |
322 | void AliTRDv2::DrawModule() | |
323 | { | |
324 | // | |
325 | // Draw a shaded view of the Transition Radiation Detector version 1 | |
326 | // | |
327 | ||
328 | AliMC* pMC = AliMC::GetMC(); | |
329 | ||
330 | // Set everything unseen | |
331 | pMC->Gsatt("*", "seen", -1); | |
332 | // | |
333 | // Set ALIC mother transparent | |
334 | pMC->Gsatt("ALIC","SEEN",0); | |
335 | // | |
336 | // Set the volumes visible | |
337 | pMC->Gsatt("TRD","SEEN",0); | |
338 | pMC->Gsatt("UTRS","SEEN",0); | |
339 | pMC->Gsatt("UTSP","SEEN",0); | |
340 | pMC->Gsatt("UTII","SEEN",0); | |
341 | pMC->Gsatt("UTIO","SEEN",0); | |
342 | pMC->Gsatt("UCI1","SEEN",0); | |
343 | pMC->Gsatt("UII1","SEEN",0); | |
344 | pMC->Gsatt("UCO1","SEEN",0); | |
345 | pMC->Gsatt("UIO1","SEEN",0); | |
346 | pMC->Gsatt("UCI2","SEEN",0); | |
347 | pMC->Gsatt("UII2","SEEN",0); | |
348 | pMC->Gsatt("UCO2","SEEN",0); | |
349 | pMC->Gsatt("UIO2","SEEN",0); | |
350 | pMC->Gsatt("UCI3","SEEN",0); | |
351 | pMC->Gsatt("UII3","SEEN",0); | |
352 | pMC->Gsatt("UCO3","SEEN",0); | |
353 | pMC->Gsatt("UIO3","SEEN",0); | |
354 | pMC->Gsatt("UCI4","SEEN",0); | |
355 | pMC->Gsatt("UII4","SEEN",0); | |
356 | pMC->Gsatt("UCO4","SEEN",0); | |
357 | pMC->Gsatt("UIO4","SEEN",0); | |
358 | pMC->Gsatt("UCI5","SEEN",0); | |
359 | pMC->Gsatt("UII5","SEEN",0); | |
360 | pMC->Gsatt("UCO5","SEEN",0); | |
361 | pMC->Gsatt("UIO5","SEEN",0); | |
362 | pMC->Gsatt("UCI6","SEEN",0); | |
363 | pMC->Gsatt("UII6","SEEN",0); | |
364 | pMC->Gsatt("UCO6","SEEN",0); | |
365 | pMC->Gsatt("UIO6","SEEN",0); | |
366 | pMC->Gsatt("UT1I","SEEN",1); | |
367 | pMC->Gsatt("UXI1","SEEN",1); | |
368 | pMC->Gsatt("UXI2","SEEN",1); | |
369 | pMC->Gsatt("UXI3","SEEN",1); | |
370 | pMC->Gsatt("UXI4","SEEN",1); | |
371 | pMC->Gsatt("UXI5","SEEN",1); | |
372 | pMC->Gsatt("UXI6","SEEN",1); | |
373 | pMC->Gsatt("UT1O","SEEN",1); | |
374 | pMC->Gsatt("UXO1","SEEN",1); | |
375 | pMC->Gsatt("UXO2","SEEN",1); | |
376 | pMC->Gsatt("UXO3","SEEN",1); | |
377 | pMC->Gsatt("UXO4","SEEN",1); | |
378 | pMC->Gsatt("UXO5","SEEN",1); | |
379 | pMC->Gsatt("UXO6","SEEN",1); | |
380 | // | |
381 | pMC->Gdopt("hide", "on"); | |
382 | pMC->Gdopt("shad", "on"); | |
383 | pMC->Gsatt("*", "fill", 7); | |
384 | pMC->SetClipBox("."); | |
385 | pMC->SetClipBox("*", 0, 2000, -2000, 2000, -2000, 2000); | |
386 | pMC->DefaultRange(); | |
387 | pMC->Gdraw("alic", 40, 30, 0, 12, 9.4, .021, .021); | |
388 | pMC->Gdhead(1111, "Transition Radiation Detector Version 2"); | |
389 | pMC->Gdman(18, 4, "MAN"); | |
390 | pMC->Gdopt("hide", "off"); | |
391 | } | |
392 | ||
393 | //_____________________________________________________________________________ | |
394 | void AliTRDv2::CreateMaterials() | |
395 | { | |
396 | // | |
397 | // Create materials for the Transition Radiation Detector version 2 | |
398 | // | |
399 | printf("TRD: Slow simulation with fine geometry\n"); | |
400 | AliTRD::CreateMaterials(); | |
401 | } | |
402 | ||
403 | //_____________________________________________________________________________ | |
404 | void AliTRDv2::Init() | |
405 | { | |
406 | // | |
407 | // Initialise Transition Radiation Detector after geometry has been built | |
408 | // | |
409 | AliTRD::Init(); | |
410 | AliMC* pMC = AliMC::GetMC(); | |
411 | fIdSenI1 = pMC->VolId("UXI1"); | |
412 | fIdSenI2 = pMC->VolId("UXI2"); | |
413 | fIdSenI3 = pMC->VolId("UXI3"); | |
414 | fIdSenI4 = pMC->VolId("UXI4"); | |
415 | fIdSenI5 = pMC->VolId("UXI5"); | |
416 | fIdSenI6 = pMC->VolId("UXI6"); | |
417 | ||
418 | fIdSenO1 = pMC->VolId("UXO1"); | |
419 | fIdSenO2 = pMC->VolId("UXO2"); | |
420 | fIdSenO3 = pMC->VolId("UXO3"); | |
421 | fIdSenO4 = pMC->VolId("UXO4"); | |
422 | fIdSenO5 = pMC->VolId("UXO5"); | |
423 | fIdSenO6 = pMC->VolId("UXO6"); | |
424 | } | |
425 | ||
426 | //_____________________________________________________________________________ | |
427 | void AliTRDv2::StepManager() | |
428 | { | |
429 | // | |
430 | // Called at every step in the Transition Radiation Detector version 2 | |
431 | // | |
432 | Int_t idSens, icSens; | |
433 | Int_t iPla, iCha, iSec; | |
434 | Int_t iOut; | |
435 | Int_t vol[3]; | |
436 | Int_t iPid; | |
437 | ||
438 | const Float_t kBig = 1.0E+12; | |
439 | ||
440 | Float_t random[1]; | |
441 | Float_t charge; | |
442 | Float_t betaGamma, pp; | |
443 | Float_t aMass; | |
444 | Float_t eLos, qTot; | |
445 | Float_t hits[4]; | |
446 | Float_t mom[4]; | |
447 | Float_t pTot; | |
448 | ||
449 | TClonesArray &lhits = *fHits; | |
450 | ||
451 | AliMC* pMC = AliMC::GetMC(); | |
452 | ||
453 | // Ionization energy | |
454 | // taken from: Ionization Measurements in High Energy Physics, Springer | |
455 | const Double_t kWion = 23.0E-9; | |
456 | // Maximum energy for e+ e- g for the step-size calculation | |
457 | const Float_t kPTotMax = 0.002; | |
458 | // Plateau value of the energy-loss for electron in xenon | |
459 | // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253 | |
460 | const Float_t kPlateau = 1.70; | |
461 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) | |
462 | // taken from: Ionization Measurements in High Energy Physics, Springer | |
463 | const Float_t kPrim = 43.68; | |
464 | ||
465 | // Set the maximum step size to a very large number for all | |
466 | // neutral particles and those outside the driftvolume | |
467 | pMC->SetMaxStep(kBig); | |
468 | ||
469 | // Use only charged tracks | |
470 | if (( pMC->TrackCharge() ) && | |
471 | (!pMC->TrackStop() ) && | |
472 | (!pMC->TrackDisappear())) { | |
473 | ||
474 | // Find the sensitive volume | |
475 | idSens = pMC->CurrentVol(0,icSens); | |
476 | iPla = 0; | |
477 | iOut = 0; | |
478 | if (idSens == fIdSenI1) iPla = 1; | |
479 | else if (idSens == fIdSenI2) iPla = 2; | |
480 | else if (idSens == fIdSenI3) iPla = 3; | |
481 | else if (idSens == fIdSenI4) iPla = 4; | |
482 | else if (idSens == fIdSenI5) iPla = 5; | |
483 | else if (idSens == fIdSenI6) iPla = 6; | |
484 | else if (idSens == fIdSenO1) { | |
485 | iPla = 1; | |
486 | iOut = 1; } | |
487 | else if (idSens == fIdSenO2) { | |
488 | iPla = 2; | |
489 | iOut = 1; } | |
490 | else if (idSens == fIdSenO3) { | |
491 | iPla = 3; | |
492 | iOut = 1; } | |
493 | else if (idSens == fIdSenO4) { | |
494 | iPla = 4; | |
495 | iOut = 1; } | |
496 | else if (idSens == fIdSenO5) { | |
497 | iPla = 5; | |
498 | iOut = 1; } | |
499 | else if (idSens == fIdSenO6) { | |
500 | iPla = 6; | |
501 | iOut = 1; } | |
502 | ||
503 | // Inside a sensitive volume? | |
504 | if (iPla) { | |
505 | ||
506 | // Calculate the energy loss | |
507 | // ((1/E^2.0) distribution for the fluctuations) | |
508 | pMC->Rndm(random,1); | |
509 | eLos = Eloss(random[0]); | |
510 | ||
511 | // The amount of charge created | |
512 | qTot = (Float_t) ((Int_t) (eLos / kWion) + 1); | |
513 | ||
514 | // The sector number | |
515 | pMC->CurrentVolOff(5,0,iSec); | |
516 | ||
517 | // The chamber number | |
518 | pMC->CurrentVolOff(4,0,iCha); | |
519 | if (iOut) | |
520 | iCha = (iCha - 1) * 3 + 1; | |
521 | else | |
522 | iCha = iCha + 1; | |
523 | ||
524 | vol[0] = iSec; | |
525 | vol[1] = iCha; | |
526 | vol[2] = iPla; | |
527 | ||
528 | pMC->TrackPosition(hits); | |
529 | hits[3] = qTot; | |
530 | ||
531 | // Add the hit | |
532 | new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack(),vol,hits); | |
533 | ||
534 | pMC->TrackMomentum(mom); | |
535 | pTot = mom[3]; | |
536 | ||
537 | // New step size for electrons only if momentum is small enough | |
538 | iPid = pMC->TrackPid(); | |
539 | if ( (iPid > 3) || | |
540 | ((iPid <= 3) && (pTot < kPTotMax))) { | |
541 | aMass = pMC->TrackMass(); | |
542 | betaGamma = pTot / aMass; | |
543 | pp = kPrim * BetheBloch(betaGamma); | |
544 | // Take charge > 1 into account | |
545 | charge = pMC->TrackCharge(); | |
546 | if (TMath::Abs(charge) > 1) pp = pp * charge*charge; | |
547 | } | |
548 | // Electrons above 20 Mev/c are at the plateau | |
549 | else { | |
550 | pp = kPrim * kPlateau; | |
551 | } | |
552 | ||
553 | // Calculate the maximum step size for the next tracking step | |
554 | do | |
555 | pMC->Rndm(random,1); | |
556 | while ((random[0] == 1.) || (random[0] == 0.)); | |
557 | pMC->SetMaxStep( - TMath::Log(random[0]) / pp); | |
558 | ||
559 | } | |
560 | } | |
561 | } |