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4c039060 | 1 | /************************************************************************** |
2 | * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * | |
3 | * * | |
4 | * Author: The ALICE Off-line Project. * | |
5 | * Contributors are mentioned in the code where appropriate. * | |
6 | * * | |
7 | * Permission to use, copy, modify and distribute this software and its * | |
8 | * documentation strictly for non-commercial purposes is hereby granted * | |
9 | * without fee, provided that the above copyright notice appears in all * | |
10 | * copies and that both the copyright notice and this permission notice * | |
11 | * appear in the supporting documentation. The authors make no claims * | |
12 | * about the suitability of this software for any purpose. It is * | |
13 | * provided "as is" without express or implied warranty. * | |
14 | **************************************************************************/ | |
15 | ||
88cb7938 | 16 | /* $Id$ */ |
4c039060 | 17 | |
030b4415 | 18 | //////////////////////////////////////////////////////////////////////////// |
19 | // // | |
20 | // Transition Radiation Detector version 1 -- slow simulator // | |
21 | // // | |
22 | //////////////////////////////////////////////////////////////////////////// | |
fe4da5cc | 23 | |
769257f4 | 24 | #include <stdlib.h> |
25 | ||
793ff80c | 26 | #include <TF1.h> |
1819f4bb | 27 | #include <TLorentzVector.h> |
88cb7938 | 28 | #include <TMath.h> |
29 | #include <TRandom.h> | |
30 | #include <TVector.h> | |
31 | #include <TVirtualMC.h> | |
f57bb418 | 32 | #include <TGeoManager.h> |
fe4da5cc | 33 | |
d3f347ff | 34 | #include "AliConst.h" |
45160b1f | 35 | #include "AliLog.h" |
36 | #include "AliMC.h" | |
88cb7938 | 37 | #include "AliRun.h" |
030b4415 | 38 | |
88cb7938 | 39 | #include "AliTRDgeometry.h" |
793ff80c | 40 | #include "AliTRDhit.h" |
793ff80c | 41 | #include "AliTRDsim.h" |
88cb7938 | 42 | #include "AliTRDv1.h" |
851d3db9 | 43 | |
fe4da5cc | 44 | ClassImp(AliTRDv1) |
8230f242 | 45 | |
46 | //_____________________________________________________________________________ | |
030b4415 | 47 | AliTRDv1::AliTRDv1() |
48 | :AliTRD() | |
49 | ,fTRon(kFALSE) | |
50 | ,fTR(NULL) | |
51 | ,fTypeOfStepManager(0) | |
52 | ,fStepSize(0) | |
53 | ,fDeltaE(NULL) | |
54 | ,fDeltaG(NULL) | |
55 | ,fTrackLength0(0) | |
56 | ,fPrimaryTrackPid(0) | |
8230f242 | 57 | { |
58 | // | |
59 | // Default constructor | |
60 | // | |
61 | ||
8230f242 | 62 | } |
63 | ||
fe4da5cc | 64 | //_____________________________________________________________________________ |
65 | AliTRDv1::AliTRDv1(const char *name, const char *title) | |
030b4415 | 66 | :AliTRD(name,title) |
67 | ,fTRon(kTRUE) | |
68 | ,fTR(NULL) | |
67c47633 | 69 | ,fTypeOfStepManager(2) |
030b4415 | 70 | ,fStepSize(0.1) |
71 | ,fDeltaE(NULL) | |
72 | ,fDeltaG(NULL) | |
73 | ,fTrackLength0(0) | |
74 | ,fPrimaryTrackPid(0) | |
fe4da5cc | 75 | { |
76 | // | |
851d3db9 | 77 | // Standard constructor for Transition Radiation Detector version 1 |
fe4da5cc | 78 | // |
82bbf98a | 79 | |
5c7f4665 | 80 | SetBufferSize(128000); |
81 | ||
82 | } | |
83 | ||
8230f242 | 84 | //_____________________________________________________________________________ |
030b4415 | 85 | AliTRDv1::AliTRDv1(const AliTRDv1 &trd) |
86 | :AliTRD(trd) | |
87 | ,fTRon(trd.fTRon) | |
88 | ,fTR(NULL) | |
89 | ,fTypeOfStepManager(trd.fTypeOfStepManager) | |
90 | ,fStepSize(trd.fStepSize) | |
91 | ,fDeltaE(NULL) | |
92 | ,fDeltaG(NULL) | |
93 | ,fTrackLength0(trd.fTrackLength0) | |
94 | ,fPrimaryTrackPid(trd.fPrimaryTrackPid) | |
8230f242 | 95 | { |
96 | // | |
97 | // Copy constructor | |
98 | // | |
99 | ||
030b4415 | 100 | fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE); |
101 | fDeltaG->Copy(*((AliTRDv1 &) trd).fDeltaG); | |
102 | fTR->Copy(*((AliTRDv1 &) trd).fTR); | |
8230f242 | 103 | |
104 | } | |
105 | ||
5c7f4665 | 106 | //_____________________________________________________________________________ |
107 | AliTRDv1::~AliTRDv1() | |
108 | { | |
dd9a6ee3 | 109 | // |
110 | // AliTRDv1 destructor | |
111 | // | |
82bbf98a | 112 | |
030b4415 | 113 | if (fDeltaE) { |
114 | delete fDeltaE; | |
115 | fDeltaE = 0; | |
116 | } | |
117 | ||
118 | if (fDeltaG) { | |
119 | delete fDeltaG; | |
120 | fDeltaG = 0; | |
121 | } | |
122 | ||
123 | if (fTR) { | |
124 | delete fTR; | |
125 | fTR = 0; | |
126 | } | |
82bbf98a | 127 | |
fe4da5cc | 128 | } |
129 | ||
dd9a6ee3 | 130 | //_____________________________________________________________________________ |
131 | AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd) | |
132 | { | |
133 | // | |
134 | // Assignment operator | |
135 | // | |
136 | ||
137 | if (this != &trd) ((AliTRDv1 &) trd).Copy(*this); | |
030b4415 | 138 | |
dd9a6ee3 | 139 | return *this; |
140 | ||
141 | } | |
8230f242 | 142 | |
143 | //_____________________________________________________________________________ | |
e0d47c25 | 144 | void AliTRDv1::Copy(TObject &trd) const |
8230f242 | 145 | { |
146 | // | |
147 | // Copy function | |
148 | // | |
149 | ||
a328fff9 | 150 | ((AliTRDv1 &) trd).fTypeOfStepManager = fTypeOfStepManager; |
151 | ((AliTRDv1 &) trd).fStepSize = fStepSize; | |
bd0f8685 | 152 | ((AliTRDv1 &) trd).fTRon = fTRon; |
030b4415 | 153 | ((AliTRDv1 &) trd).fTrackLength0 = fTrackLength0; |
154 | ((AliTRDv1 &) trd).fPrimaryTrackPid = fPrimaryTrackPid; | |
bd0f8685 | 155 | |
793ff80c | 156 | fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE); |
a328fff9 | 157 | fDeltaG->Copy(*((AliTRDv1 &) trd).fDeltaG); |
793ff80c | 158 | fTR->Copy(*((AliTRDv1 &) trd).fTR); |
8230f242 | 159 | |
160 | } | |
161 | ||
f57bb418 | 162 | //_____________________________________________________________________________ |
163 | void AliTRDv1::AddAlignableVolumes() const | |
164 | { | |
165 | // | |
166 | // Create entries for alignable volumes associating the symbolic volume | |
167 | // name with the corresponding volume path. Needs to be syncronized with | |
168 | // eventual changes in the geometry. | |
169 | // | |
170 | ||
171 | TString volPath; | |
172 | TString symName; | |
173 | ||
174 | TString vpStr = "ALIC_1/B077_1/BSEGMO"; | |
175 | TString vpApp1 = "_1/BTRD"; | |
176 | TString vpApp2 = "_1"; | |
177 | TString vpApp3 = "/UTR1_1/UTS1_1/UTI1_1/UT"; | |
178 | ||
179 | TString snStr = "TRD/sm"; | |
180 | TString snApp1 = "/st"; | |
181 | TString snApp2 = "/pl"; | |
182 | ||
183 | // | |
184 | // The super modules | |
185 | // The symbolic names are: TRD/sm00 | |
186 | // ... | |
187 | // TRD/sm17 | |
188 | // | |
189 | for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) { | |
190 | ||
191 | volPath = vpStr; | |
192 | volPath += isect; | |
193 | volPath += vpApp1; | |
194 | volPath += isect; | |
195 | volPath += vpApp2; | |
196 | ||
197 | symName = snStr; | |
198 | symName += Form("%02d",isect); | |
199 | ||
200 | gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data()); | |
201 | ||
202 | } | |
203 | ||
204 | // | |
205 | // The readout chambers | |
206 | // The symbolic names are: TRD/sm00/st0/pl0 | |
207 | // ... | |
208 | // TRD/sm17/st4/pl5 | |
209 | // | |
210 | for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) { | |
211 | for (Int_t icham = 0; icham < AliTRDgeometry::Ncham(); icham++) { | |
212 | for (Int_t iplan = 0; iplan < AliTRDgeometry::Nplan(); iplan++) { | |
213 | ||
214 | Int_t idet = AliTRDgeometry::GetDetectorSec(iplan,icham); | |
215 | ||
216 | volPath = vpStr; | |
217 | volPath += isect; | |
218 | volPath += vpApp1; | |
219 | volPath += isect; | |
220 | volPath += vpApp2; | |
221 | volPath += vpApp3; | |
222 | volPath += Form("%02d",idet); | |
223 | volPath += vpApp2; | |
224 | ||
225 | symName = snStr; | |
226 | symName += Form("%02d",isect); | |
227 | symName += snApp1; | |
228 | symName += icham; | |
229 | symName += snApp2; | |
230 | symName += iplan; | |
231 | ||
f57bb418 | 232 | gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data()); |
233 | ||
234 | } | |
235 | } | |
236 | } | |
237 | ||
238 | } | |
239 | ||
fe4da5cc | 240 | //_____________________________________________________________________________ |
241 | void AliTRDv1::CreateGeometry() | |
242 | { | |
243 | // | |
851d3db9 | 244 | // Create the GEANT geometry for the Transition Radiation Detector - Version 1 |
5c7f4665 | 245 | // This version covers the full azimuth. |
d3f347ff | 246 | // |
247 | ||
82bbf98a | 248 | // Check that FRAME is there otherwise we have no place where to put the TRD |
8230f242 | 249 | AliModule* frame = gAlice->GetModule("FRAME"); |
030b4415 | 250 | if (!frame) { |
251 | AliError("TRD needs FRAME to be present\n"); | |
252 | return; | |
253 | } | |
d3f347ff | 254 | |
82bbf98a | 255 | // Define the chambers |
256 | AliTRD::CreateGeometry(); | |
d3f347ff | 257 | |
fe4da5cc | 258 | } |
259 | ||
260 | //_____________________________________________________________________________ | |
261 | void AliTRDv1::CreateMaterials() | |
262 | { | |
263 | // | |
851d3db9 | 264 | // Create materials for the Transition Radiation Detector version 1 |
fe4da5cc | 265 | // |
82bbf98a | 266 | |
d3f347ff | 267 | AliTRD::CreateMaterials(); |
82bbf98a | 268 | |
fe4da5cc | 269 | } |
270 | ||
793ff80c | 271 | //_____________________________________________________________________________ |
272 | void AliTRDv1::CreateTRhit(Int_t det) | |
273 | { | |
274 | // | |
275 | // Creates an electron cluster from a TR photon. | |
276 | // The photon is assumed to be created a the end of the radiator. The | |
277 | // distance after which it deposits its energy takes into account the | |
278 | // absorbtion of the entrance window and of the gas mixture in drift | |
279 | // volume. | |
280 | // | |
281 | ||
282 | // PDG code electron | |
283 | const Int_t kPdgElectron = 11; | |
284 | ||
285 | // Ionization energy | |
bc327ce2 | 286 | const Float_t kWion = 23.53; |
793ff80c | 287 | |
288 | // Maximum number of TR photons per track | |
289 | const Int_t kNTR = 50; | |
290 | ||
030b4415 | 291 | TLorentzVector mom; |
292 | TLorentzVector pos; | |
793ff80c | 293 | |
793ff80c | 294 | // Create TR at the entrance of the chamber |
295 | if (gMC->IsTrackEntering()) { | |
296 | ||
f73816f5 | 297 | // Create TR only for electrons |
298 | Int_t iPdg = gMC->TrackPid(); | |
030b4415 | 299 | if (TMath::Abs(iPdg) != kPdgElectron) { |
300 | return; | |
301 | } | |
f73816f5 | 302 | |
793ff80c | 303 | Float_t eTR[kNTR]; |
304 | Int_t nTR; | |
305 | ||
306 | // Create TR photons | |
307 | gMC->TrackMomentum(mom); | |
308 | Float_t pTot = mom.Rho(); | |
309 | fTR->CreatePhotons(iPdg,pTot,nTR,eTR); | |
310 | if (nTR > kNTR) { | |
45160b1f | 311 | AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR)); |
793ff80c | 312 | } |
313 | ||
314 | // Loop through the TR photons | |
315 | for (Int_t iTR = 0; iTR < nTR; iTR++) { | |
316 | ||
317 | Float_t energyMeV = eTR[iTR] * 0.001; | |
318 | Float_t energyeV = eTR[iTR] * 1000.0; | |
030b4415 | 319 | Float_t absLength = 0.0; |
320 | Float_t sigma = 0.0; | |
793ff80c | 321 | |
322 | // Take the absorbtion in the entrance window into account | |
323 | Double_t muMy = fTR->GetMuMy(energyMeV); | |
030b4415 | 324 | sigma = muMy * fFoilDensity; |
842287f2 | 325 | if (sigma > 0.0) { |
326 | absLength = gRandom->Exp(1.0/sigma); | |
030b4415 | 327 | if (absLength < AliTRDgeometry::MyThick()) { |
328 | continue; | |
329 | } | |
842287f2 | 330 | } |
331 | else { | |
332 | continue; | |
333 | } | |
793ff80c | 334 | |
335 | // The absorbtion cross sections in the drift gas | |
3dac2b2d | 336 | // Gas-mixture (Xe/CO2) |
337 | Double_t muXe = fTR->GetMuXe(energyMeV); | |
338 | Double_t muCO = fTR->GetMuCO(energyMeV); | |
339 | sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity * fTR->GetTemp(); | |
793ff80c | 340 | |
341 | // The distance after which the energy of the TR photon | |
342 | // is deposited. | |
842287f2 | 343 | if (sigma > 0.0) { |
344 | absLength = gRandom->Exp(1.0/sigma); | |
a328fff9 | 345 | if (absLength > (AliTRDgeometry::DrThick() |
346 | + AliTRDgeometry::AmThick())) { | |
347 | continue; | |
348 | } | |
842287f2 | 349 | } |
350 | else { | |
351 | continue; | |
352 | } | |
793ff80c | 353 | |
354 | // The position of the absorbtion | |
355 | Float_t posHit[3]; | |
356 | gMC->TrackPosition(pos); | |
357 | posHit[0] = pos[0] + mom[0] / pTot * absLength; | |
358 | posHit[1] = pos[1] + mom[1] / pTot * absLength; | |
c4214bc0 | 359 | posHit[2] = pos[2] + mom[2] / pTot * absLength; |
793ff80c | 360 | |
361 | // Create the charge | |
362 | Int_t q = ((Int_t) (energyeV / kWion)); | |
363 | ||
364 | // Add the hit to the array. TR photon hits are marked | |
365 | // by negative charge | |
030b4415 | 366 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
367 | ,det | |
368 | ,posHit | |
369 | ,-q | |
370 | ,kTRUE); | |
793ff80c | 371 | |
372 | } | |
373 | ||
374 | } | |
375 | ||
376 | } | |
377 | ||
5c7f4665 | 378 | //_____________________________________________________________________________ |
379 | void AliTRDv1::Init() | |
380 | { | |
381 | // | |
382 | // Initialise Transition Radiation Detector after geometry has been built. | |
5c7f4665 | 383 | // |
384 | ||
385 | AliTRD::Init(); | |
386 | ||
45160b1f | 387 | AliDebug(1,"Slow simulator\n"); |
bd0f8685 | 388 | |
389 | // Switch on TR simulation as default | |
390 | if (!fTRon) { | |
45160b1f | 391 | AliInfo("TR simulation off"); |
bd0f8685 | 392 | } |
393 | else { | |
394 | fTR = new AliTRDsim(); | |
395 | } | |
5c7f4665 | 396 | |
397 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) | |
398 | const Float_t kPoti = 12.1; | |
399 | // Maximum energy (50 keV); | |
400 | const Float_t kEend = 50000.0; | |
401 | // Ermilova distribution for the delta-ray spectrum | |
030b4415 | 402 | Float_t poti = TMath::Log(kPoti); |
403 | Float_t eEnd = TMath::Log(kEend); | |
a328fff9 | 404 | |
405 | // Ermilova distribution for the delta-ray spectrum | |
c4214bc0 | 406 | fDeltaE = new TF1("deltae" ,Ermilova ,poti,eEnd,0); |
a328fff9 | 407 | |
408 | // Geant3 distribution for the delta-ray spectrum | |
c4214bc0 | 409 | fDeltaG = new TF1("deltag",IntSpecGeant,2.421257,28.536469,0); |
5c7f4665 | 410 | |
45160b1f | 411 | AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); |
5c7f4665 | 412 | |
fe4da5cc | 413 | } |
414 | ||
5c7f4665 | 415 | //_____________________________________________________________________________ |
416 | void AliTRDv1::StepManager() | |
a328fff9 | 417 | { |
418 | // | |
c4214bc0 | 419 | // Slow simulator. Every charged track produces electron cluster as hits |
a328fff9 | 420 | // along its path across the drift volume. |
421 | // | |
422 | ||
423 | switch (fTypeOfStepManager) { | |
a6dd11e9 | 424 | case 0: |
425 | StepManagerErmilova(); | |
426 | break; | |
427 | case 1: | |
428 | StepManagerGeant(); | |
429 | break; | |
430 | case 2: | |
431 | StepManagerFixedStep(); | |
432 | break; | |
433 | default: | |
434 | AliWarning("Not a valid Step Manager."); | |
a328fff9 | 435 | } |
436 | ||
437 | } | |
438 | ||
439 | //_____________________________________________________________________________ | |
440 | void AliTRDv1::SelectStepManager(Int_t t) | |
441 | { | |
442 | // | |
443 | // Selects a step manager type: | |
444 | // 0 - Ermilova | |
445 | // 1 - Geant3 | |
446 | // 2 - Fixed step size | |
447 | // | |
448 | ||
a328fff9 | 449 | fTypeOfStepManager = t; |
45160b1f | 450 | AliInfo(Form("Step Manager type %d was selected",fTypeOfStepManager)); |
a328fff9 | 451 | |
452 | } | |
453 | ||
454 | //_____________________________________________________________________________ | |
455 | void AliTRDv1::StepManagerGeant() | |
456 | { | |
457 | // | |
c4214bc0 | 458 | // Slow simulator. Every charged track produces electron cluster as hits |
a328fff9 | 459 | // along its path across the drift volume. The step size is set acording |
460 | // to Bethe-Bloch. The energy distribution of the delta electrons follows | |
461 | // a spectrum taken from Geant3. | |
462 | // | |
f2e3a0b5 | 463 | // Version by A. Bercuci |
464 | // | |
465 | ||
c4214bc0 | 466 | Int_t pla = 0; |
467 | Int_t cha = 0; | |
468 | Int_t sec = 0; | |
469 | Int_t det = 0; | |
470 | Int_t iPdg; | |
471 | Int_t qTot; | |
472 | ||
473 | Float_t hits[3]; | |
474 | Float_t charge; | |
475 | Float_t aMass; | |
476 | ||
030b4415 | 477 | Double_t pTot = 0; |
c4214bc0 | 478 | Double_t eDelta; |
030b4415 | 479 | Double_t betaGamma; |
480 | Double_t pp; | |
f2e3a0b5 | 481 | Double_t stepSize = 0; |
c4214bc0 | 482 | |
483 | Bool_t drRegion = kFALSE; | |
484 | Bool_t amRegion = kFALSE; | |
485 | ||
486 | TString cIdCurrent; | |
487 | TString cIdSensDr = "J"; | |
488 | TString cIdSensAm = "K"; | |
489 | Char_t cIdChamber[3]; | |
490 | cIdChamber[2] = 0; | |
491 | ||
030b4415 | 492 | TLorentzVector pos; |
493 | TLorentzVector mom; | |
c4214bc0 | 494 | |
030b4415 | 495 | TArrayI processes; |
f2e3a0b5 | 496 | |
c4214bc0 | 497 | const Int_t kNplan = AliTRDgeometry::Nplan(); |
498 | const Int_t kNcham = AliTRDgeometry::Ncham(); | |
499 | const Int_t kNdetsec = kNplan * kNcham; | |
500 | ||
030b4415 | 501 | const Double_t kBig = 1.0e+12; // Infinitely big |
bc327ce2 | 502 | const Float_t kWion = 23.53; // Ionization energy |
c4214bc0 | 503 | const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g |
504 | ||
505 | // Minimum energy for the step size adjustment | |
506 | const Float_t kEkinMinStep = 1.0e-5; | |
507 | // energy threshold for production of delta electrons | |
f2e3a0b5 | 508 | const Float_t kECut = 1.0e4; |
509 | // Parameters entering the parametrized range for delta electrons | |
030b4415 | 510 | const Float_t kRa = 5.37e-4; |
f2e3a0b5 | 511 | const Float_t kRb = 0.9815; |
030b4415 | 512 | const Float_t kRc = 3.123e-3; |
f2e3a0b5 | 513 | // Gas density -> To be made user adjustable ! |
030b4415 | 514 | // [0.85*0.00549+0.15*0.00186 (Xe-CO2 85-15)] |
515 | const Float_t kRho = 0.004945 ; | |
a328fff9 | 516 | |
c4214bc0 | 517 | // Plateau value of the energy-loss for electron in xenon |
030b4415 | 518 | // The averaged value (26/3/99) |
c4214bc0 | 519 | const Float_t kPlateau = 1.55; |
030b4415 | 520 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) |
521 | const Float_t kPrim = 19.34; | |
c4214bc0 | 522 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) |
523 | const Float_t kPoti = 12.1; | |
030b4415 | 524 | // PDG code electron |
525 | const Int_t kPdgElectron = 11; | |
c4214bc0 | 526 | |
527 | // Set the maximum step size to a very large number for all | |
528 | // neutral particles and those outside the driftvolume | |
529 | gMC->SetMaxStep(kBig); | |
530 | ||
531 | // Use only charged tracks | |
532 | if (( gMC->TrackCharge() ) && | |
c4214bc0 | 533 | (!gMC->IsTrackDisappeared())) { |
534 | ||
535 | // Inside a sensitive volume? | |
536 | drRegion = kFALSE; | |
537 | amRegion = kFALSE; | |
538 | cIdCurrent = gMC->CurrentVolName(); | |
539 | if (cIdSensDr == cIdCurrent[1]) { | |
540 | drRegion = kTRUE; | |
541 | } | |
542 | if (cIdSensAm == cIdCurrent[1]) { | |
543 | amRegion = kTRUE; | |
544 | } | |
545 | if (drRegion || amRegion) { | |
a328fff9 | 546 | |
c4214bc0 | 547 | // The hit coordinates and charge |
548 | gMC->TrackPosition(pos); | |
549 | hits[0] = pos[0]; | |
550 | hits[1] = pos[1]; | |
551 | hits[2] = pos[2]; | |
552 | ||
553 | // The sector number (0 - 17) | |
554 | // The numbering goes clockwise and starts at y = 0 | |
555 | Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]); | |
030b4415 | 556 | if (phi < 90.0) { |
557 | phi = phi + 270.0; | |
558 | } | |
559 | else { | |
560 | phi = phi - 90.0; | |
561 | } | |
562 | sec = ((Int_t) (phi / 20.0)); | |
c4214bc0 | 563 | |
564 | // The plane and chamber number | |
030b4415 | 565 | cIdChamber[0] = cIdCurrent[2]; |
566 | cIdChamber[1] = cIdCurrent[3]; | |
c4214bc0 | 567 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
568 | cha = kNcham - ((Int_t) idChamber / kNplan) - 1; | |
569 | pla = ((Int_t) idChamber % kNplan); | |
570 | ||
571 | // Check on selected volumes | |
572 | Int_t addthishit = 1; | |
c4214bc0 | 573 | |
574 | // Add this hit | |
575 | if (addthishit) { | |
576 | ||
577 | // The detector number | |
578 | det = fGeometry->GetDetector(pla,cha,sec); | |
579 | ||
580 | // Special hits only in the drift region | |
581 | if (drRegion) { | |
f2e3a0b5 | 582 | |
c4214bc0 | 583 | // Create a track reference at the entrance and |
584 | // exit of each chamber that contain the | |
f2e3a0b5 | 585 | // momentum components of the particle |
030b4415 | 586 | if (gMC->IsTrackEntering() || |
587 | gMC->IsTrackExiting()) { | |
c4214bc0 | 588 | gMC->TrackMomentum(mom); |
589 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber()); | |
590 | } | |
f2e3a0b5 | 591 | |
030b4415 | 592 | if (gMC->IsTrackEntering() && |
593 | !gMC->IsNewTrack()) { | |
f2e3a0b5 | 594 | // determine if hit belong to primary track |
595 | fPrimaryTrackPid = gAlice->GetMCApp()->GetCurrentTrackNumber(); | |
596 | // determine track length when entering the detector | |
597 | fTrackLength0 = gMC->TrackLength(); | |
598 | } | |
c4214bc0 | 599 | |
f2e3a0b5 | 600 | // Create the hits from TR photons |
c4214bc0 | 601 | if (fTR) CreateTRhit(det); |
c4214bc0 | 602 | |
f2e3a0b5 | 603 | } |
c4214bc0 | 604 | |
f2e3a0b5 | 605 | // Calculate the energy of the delta-electrons |
606 | // modified by Alex Bercuci (A.Bercuci@gsi.de) on 26.01.06 | |
607 | // take into account correlation with the underlying GEANT tracking | |
608 | // mechanism. see | |
609 | // http://www-linux.gsi.de/~abercuci/Contributions/TRD/index.html | |
610 | // | |
611 | // determine the most significant process (last on the processes list) | |
612 | // which caused this hit | |
c4214bc0 | 613 | gMC->StepProcesses(processes); |
f2e3a0b5 | 614 | Int_t nofprocesses = processes.GetSize(); |
615 | Int_t pid; | |
616 | if (!nofprocesses) { | |
617 | pid = 0; | |
618 | } | |
619 | else { | |
620 | pid = processes[nofprocesses-1]; | |
621 | } | |
622 | ||
623 | // generate Edep according to GEANT parametrisation | |
624 | eDelta = TMath::Exp(fDeltaG->GetRandom()) - kPoti; | |
625 | eDelta = TMath::Max(eDelta,0.0); | |
030b4415 | 626 | Float_t prRange = 0.0; |
627 | Float_t range = gMC->TrackLength() - fTrackLength0; | |
f2e3a0b5 | 628 | // merge GEANT tracker information with locally cooked one |
629 | if (gAlice->GetMCApp()->GetCurrentTrackNumber() == fPrimaryTrackPid) { | |
f2e3a0b5 | 630 | if (pid == 27) { |
631 | if (eDelta >= kECut) { | |
030b4415 | 632 | prRange = kRa * eDelta * 0.001 |
633 | * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho; | |
634 | if (prRange >= (3.7 - range)) { | |
635 | eDelta *= 0.1; | |
636 | } | |
f2e3a0b5 | 637 | } |
638 | } | |
639 | else if (pid == 1) { | |
640 | if (eDelta < kECut) { | |
641 | eDelta *= 0.5; | |
642 | } | |
643 | else { | |
030b4415 | 644 | prRange = kRa * eDelta * 0.001 |
645 | * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho; | |
646 | if (prRange >= ((AliTRDgeometry::DrThick() | |
647 | + AliTRDgeometry::AmThick()) - range)) { | |
f2e3a0b5 | 648 | eDelta *= 0.05; |
649 | } | |
650 | else { | |
651 | eDelta *= 0.5; | |
652 | } | |
653 | } | |
654 | } | |
655 | else { | |
656 | eDelta = 0.0; | |
657 | } | |
658 | } | |
659 | else { | |
660 | eDelta = 0.0; | |
661 | } | |
c4214bc0 | 662 | |
663 | // Generate the electron cluster size | |
f2e3a0b5 | 664 | if (eDelta == 0.0) { |
665 | qTot = 0; | |
666 | } | |
667 | else { | |
668 | qTot = ((Int_t) (eDelta / kWion) + 1); | |
669 | } | |
670 | ||
671 | // Create a new dEdx hit | |
030b4415 | 672 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
673 | ,det | |
674 | ,hits | |
675 | ,qTot | |
676 | ,drRegion); | |
c4214bc0 | 677 | |
678 | // Calculate the maximum step size for the next tracking step | |
679 | // Produce only one hit if Ekin is below cutoff | |
680 | aMass = gMC->TrackMass(); | |
681 | if ((gMC->Etot() - aMass) > kEkinMinStep) { | |
682 | ||
683 | // The energy loss according to Bethe Bloch | |
f2e3a0b5 | 684 | iPdg = TMath::Abs(gMC->TrackPid()); |
685 | if ((iPdg != kPdgElectron) || | |
030b4415 | 686 | ((iPdg == kPdgElectron) && |
687 | (pTot < kPTotMaxEl))) { | |
c4214bc0 | 688 | gMC->TrackMomentum(mom); |
689 | pTot = mom.Rho(); | |
690 | betaGamma = pTot / aMass; | |
691 | pp = BetheBlochGeant(betaGamma); | |
f2e3a0b5 | 692 | // Take charge > 1 into account |
030b4415 | 693 | charge = gMC->TrackCharge(); |
f2e3a0b5 | 694 | if (TMath::Abs(charge) > 1) { |
695 | pp = pp * charge*charge; | |
696 | } | |
697 | } | |
698 | else { | |
699 | // Electrons above 20 Mev/c are at the plateau | |
700 | pp = kPrim * kPlateau; | |
c4214bc0 | 701 | } |
702 | ||
1b775a44 | 703 | Int_t nsteps = 0; |
030b4415 | 704 | do { |
705 | nsteps = gRandom->Poisson(pp); | |
706 | } while(!nsteps); | |
707 | stepSize = 1.0 / nsteps; | |
1b775a44 | 708 | gMC->SetMaxStep(stepSize); |
f2e3a0b5 | 709 | |
1b775a44 | 710 | } |
f2e3a0b5 | 711 | |
c4214bc0 | 712 | } |
f2e3a0b5 | 713 | |
c4214bc0 | 714 | } |
f2e3a0b5 | 715 | |
c4214bc0 | 716 | } |
f2e3a0b5 | 717 | |
a328fff9 | 718 | } |
719 | ||
720 | //_____________________________________________________________________________ | |
721 | void AliTRDv1::StepManagerErmilova() | |
5c7f4665 | 722 | { |
723 | // | |
5c7f4665 | 724 | // Slow simulator. Every charged track produces electron cluster as hits |
725 | // along its path across the drift volume. The step size is set acording | |
726 | // to Bethe-Bloch. The energy distribution of the delta electrons follows | |
727 | // a spectrum taken from Ermilova et al. | |
728 | // | |
729 | ||
851d3db9 | 730 | Int_t pla = 0; |
731 | Int_t cha = 0; | |
732 | Int_t sec = 0; | |
793ff80c | 733 | Int_t det = 0; |
851d3db9 | 734 | Int_t iPdg; |
793ff80c | 735 | Int_t qTot; |
5c7f4665 | 736 | |
793ff80c | 737 | Float_t hits[3]; |
a5cadd36 | 738 | Double_t random[1]; |
5c7f4665 | 739 | Float_t charge; |
740 | Float_t aMass; | |
741 | ||
030b4415 | 742 | Double_t pTot = 0.0; |
5c7f4665 | 743 | Double_t eDelta; |
030b4415 | 744 | Double_t betaGamma; |
745 | Double_t pp; | |
f73816f5 | 746 | Double_t stepSize; |
5c7f4665 | 747 | |
332e9569 | 748 | Bool_t drRegion = kFALSE; |
749 | Bool_t amRegion = kFALSE; | |
750 | ||
751 | TString cIdCurrent; | |
752 | TString cIdSensDr = "J"; | |
753 | TString cIdSensAm = "K"; | |
593a9fc3 | 754 | Char_t cIdChamber[3]; |
755 | cIdChamber[2] = 0; | |
332e9569 | 756 | |
030b4415 | 757 | TLorentzVector pos; |
758 | TLorentzVector mom; | |
82bbf98a | 759 | |
332e9569 | 760 | const Int_t kNplan = AliTRDgeometry::Nplan(); |
e644678a | 761 | const Int_t kNcham = AliTRDgeometry::Ncham(); |
762 | const Int_t kNdetsec = kNplan * kNcham; | |
763 | ||
030b4415 | 764 | const Double_t kBig = 1.0e+12; // Infinitely big |
bc327ce2 | 765 | const Float_t kWion = 23.53; // Ionization energy |
a328fff9 | 766 | const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g |
5c7f4665 | 767 | |
f73816f5 | 768 | // Minimum energy for the step size adjustment |
769 | const Float_t kEkinMinStep = 1.0e-5; | |
a328fff9 | 770 | |
5c7f4665 | 771 | // Plateau value of the energy-loss for electron in xenon |
030b4415 | 772 | // The averaged value (26/3/99) |
a3c76cdc | 773 | const Float_t kPlateau = 1.55; |
030b4415 | 774 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) |
775 | const Float_t kPrim = 48.0; | |
5c7f4665 | 776 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) |
a3c76cdc | 777 | const Float_t kPoti = 12.1; |
030b4415 | 778 | // PDG code electron |
779 | const Int_t kPdgElectron = 11; | |
5c7f4665 | 780 | |
781 | // Set the maximum step size to a very large number for all | |
782 | // neutral particles and those outside the driftvolume | |
783 | gMC->SetMaxStep(kBig); | |
784 | ||
785 | // Use only charged tracks | |
786 | if (( gMC->TrackCharge() ) && | |
5c7f4665 | 787 | (!gMC->IsTrackDisappeared())) { |
fe4da5cc | 788 | |
5c7f4665 | 789 | // Inside a sensitive volume? |
332e9569 | 790 | drRegion = kFALSE; |
791 | amRegion = kFALSE; | |
792 | cIdCurrent = gMC->CurrentVolName(); | |
e6674585 | 793 | if (cIdSensDr == cIdCurrent[1]) { |
332e9569 | 794 | drRegion = kTRUE; |
795 | } | |
e6674585 | 796 | if (cIdSensAm == cIdCurrent[1]) { |
332e9569 | 797 | amRegion = kTRUE; |
798 | } | |
799 | if (drRegion || amRegion) { | |
fe4da5cc | 800 | |
5c7f4665 | 801 | // The hit coordinates and charge |
802 | gMC->TrackPosition(pos); | |
803 | hits[0] = pos[0]; | |
804 | hits[1] = pos[1]; | |
805 | hits[2] = pos[2]; | |
5c7f4665 | 806 | |
851d3db9 | 807 | // The sector number (0 - 17) |
808 | // The numbering goes clockwise and starts at y = 0 | |
e15eb584 | 809 | Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]); |
030b4415 | 810 | if (phi < 90.0) { |
811 | phi = phi + 270.0; | |
812 | } | |
813 | else { | |
814 | phi = phi - 90.0; | |
815 | } | |
816 | sec = ((Int_t) (phi / 20.0)); | |
82bbf98a | 817 | |
332e9569 | 818 | // The plane and chamber number |
819 | cIdChamber[0] = cIdCurrent[2]; | |
820 | cIdChamber[1] = cIdCurrent[3]; | |
e644678a | 821 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
a5cadd36 | 822 | cha = kNcham - ((Int_t) idChamber / kNplan) - 1; |
332e9569 | 823 | pla = ((Int_t) idChamber % kNplan); |
82bbf98a | 824 | |
5c7f4665 | 825 | // Check on selected volumes |
826 | Int_t addthishit = 1; | |
5c7f4665 | 827 | |
828 | // Add this hit | |
829 | if (addthishit) { | |
830 | ||
f73816f5 | 831 | // The detector number |
793ff80c | 832 | det = fGeometry->GetDetector(pla,cha,sec); |
833 | ||
a328fff9 | 834 | // Special hits only in the drift region |
332e9569 | 835 | if (drRegion) { |
f73816f5 | 836 | |
c61f1a66 | 837 | // Create a track reference at the entrance and |
838 | // exit of each chamber that contain the | |
839 | // momentum components of the particle | |
030b4415 | 840 | if (gMC->IsTrackEntering() || |
841 | gMC->IsTrackExiting()) { | |
f73816f5 | 842 | gMC->TrackMomentum(mom); |
5d12ce38 | 843 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber()); |
f73816f5 | 844 | } |
f73816f5 | 845 | // Create the hits from TR photons |
030b4415 | 846 | if (fTR) { |
847 | CreateTRhit(det); | |
848 | } | |
f73816f5 | 849 | |
030b4415 | 850 | } |
f73816f5 | 851 | |
852 | // Calculate the energy of the delta-electrons | |
853 | eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti; | |
854 | eDelta = TMath::Max(eDelta,0.0); | |
c4214bc0 | 855 | // Generate the electron cluster size |
030b4415 | 856 | if (eDelta == 0.0) { |
857 | qTot = 0; | |
858 | } | |
859 | else { | |
860 | qTot = ((Int_t) (eDelta / kWion) + 1); | |
861 | } | |
f73816f5 | 862 | |
030b4415 | 863 | // Create a new dEdx hit |
332e9569 | 864 | if (drRegion) { |
a328fff9 | 865 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 866 | ,det |
867 | ,hits | |
868 | ,qTot | |
869 | ,kTRUE); | |
870 | } | |
5c7f4665 | 871 | else { |
a328fff9 | 872 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 873 | ,det |
874 | ,hits | |
875 | ,qTot | |
876 | ,kFALSE); | |
877 | } | |
f73816f5 | 878 | |
5c7f4665 | 879 | // Calculate the maximum step size for the next tracking step |
f73816f5 | 880 | // Produce only one hit if Ekin is below cutoff |
881 | aMass = gMC->TrackMass(); | |
882 | if ((gMC->Etot() - aMass) > kEkinMinStep) { | |
883 | ||
884 | // The energy loss according to Bethe Bloch | |
885 | iPdg = TMath::Abs(gMC->TrackPid()); | |
030b4415 | 886 | if ((iPdg != kPdgElectron) || |
887 | ((iPdg == kPdgElectron) && | |
888 | (pTot < kPTotMaxEl))) { | |
f73816f5 | 889 | gMC->TrackMomentum(mom); |
890 | pTot = mom.Rho(); | |
891 | betaGamma = pTot / aMass; | |
892 | pp = kPrim * BetheBloch(betaGamma); | |
893 | // Take charge > 1 into account | |
894 | charge = gMC->TrackCharge(); | |
030b4415 | 895 | if (TMath::Abs(charge) > 1) { |
896 | pp = pp * charge*charge; | |
897 | } | |
898 | } | |
899 | else { | |
900 | // Electrons above 20 Mev/c are at the plateau | |
901 | pp = kPrim * kPlateau; | |
f73816f5 | 902 | } |
903 | ||
030b4415 | 904 | if (pp > 0.0) { |
905 | do { | |
906 | gMC->GetRandom()->RndmArray(1,random); | |
907 | } | |
908 | while ((random[0] == 1.0) || | |
909 | (random[0] == 0.0)); | |
f73816f5 | 910 | stepSize = - TMath::Log(random[0]) / pp; |
911 | gMC->SetMaxStep(stepSize); | |
030b4415 | 912 | } |
913 | ||
914 | } | |
915 | ||
5c7f4665 | 916 | } |
030b4415 | 917 | |
d3f347ff | 918 | } |
030b4415 | 919 | |
5c7f4665 | 920 | } |
030b4415 | 921 | |
5c7f4665 | 922 | } |
923 | ||
a328fff9 | 924 | //_____________________________________________________________________________ |
925 | void AliTRDv1::StepManagerFixedStep() | |
926 | { | |
927 | // | |
928 | // Slow simulator. Every charged track produces electron cluster as hits | |
929 | // along its path across the drift volume. The step size is fixed in | |
930 | // this version of the step manager. | |
931 | // | |
932 | ||
933 | Int_t pla = 0; | |
934 | Int_t cha = 0; | |
935 | Int_t sec = 0; | |
936 | Int_t det = 0; | |
937 | Int_t qTot; | |
938 | ||
939 | Float_t hits[3]; | |
940 | Double_t eDep; | |
941 | ||
942 | Bool_t drRegion = kFALSE; | |
943 | Bool_t amRegion = kFALSE; | |
944 | ||
945 | TString cIdCurrent; | |
946 | TString cIdSensDr = "J"; | |
947 | TString cIdSensAm = "K"; | |
948 | Char_t cIdChamber[3]; | |
949 | cIdChamber[2] = 0; | |
950 | ||
030b4415 | 951 | TLorentzVector pos; |
952 | TLorentzVector mom; | |
a328fff9 | 953 | |
954 | const Int_t kNplan = AliTRDgeometry::Nplan(); | |
955 | const Int_t kNcham = AliTRDgeometry::Ncham(); | |
956 | const Int_t kNdetsec = kNplan * kNcham; | |
957 | ||
030b4415 | 958 | const Double_t kBig = 1.0e+12; |
a328fff9 | 959 | |
bc327ce2 | 960 | const Float_t kWion = 23.53; // Ionization energy |
a328fff9 | 961 | const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment |
962 | ||
963 | // Set the maximum step size to a very large number for all | |
964 | // neutral particles and those outside the driftvolume | |
965 | gMC->SetMaxStep(kBig); | |
966 | ||
967 | // If not charged track or already stopped or disappeared, just return. | |
968 | if ((!gMC->TrackCharge()) || | |
a328fff9 | 969 | gMC->IsTrackDisappeared()) return; |
970 | ||
971 | // Inside a sensitive volume? | |
972 | cIdCurrent = gMC->CurrentVolName(); | |
973 | ||
974 | if (cIdSensDr == cIdCurrent[1]) drRegion = kTRUE; | |
975 | if (cIdSensAm == cIdCurrent[1]) amRegion = kTRUE; | |
976 | ||
030b4415 | 977 | if ((!drRegion) && |
978 | (!amRegion)) { | |
979 | return; | |
980 | } | |
a328fff9 | 981 | |
982 | // The hit coordinates and charge | |
983 | gMC->TrackPosition(pos); | |
984 | hits[0] = pos[0]; | |
985 | hits[1] = pos[1]; | |
986 | hits[2] = pos[2]; | |
987 | ||
988 | // The sector number (0 - 17) | |
989 | // The numbering goes clockwise and starts at y = 0 | |
990 | Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]); | |
030b4415 | 991 | if (phi < 90.0) { |
992 | phi = phi + 270.0; | |
993 | } | |
994 | else { | |
995 | phi = phi - 90.0; | |
996 | } | |
997 | sec = ((Int_t) (phi / 20.0)); | |
a328fff9 | 998 | |
999 | // The plane and chamber number | |
030b4415 | 1000 | cIdChamber[0] = cIdCurrent[2]; |
1001 | cIdChamber[1] = cIdCurrent[3]; | |
a328fff9 | 1002 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
a5cadd36 | 1003 | cha = kNcham - ((Int_t) idChamber / kNplan) - 1; |
a328fff9 | 1004 | pla = ((Int_t) idChamber % kNplan); |
e0d47c25 | 1005 | |
a328fff9 | 1006 | // Check on selected volumes |
1007 | Int_t addthishit = 1; | |
a328fff9 | 1008 | |
030b4415 | 1009 | if (!addthishit) { |
1010 | return; | |
1011 | } | |
a328fff9 | 1012 | |
030b4415 | 1013 | // The detector number |
1014 | det = fGeometry->GetDetector(pla,cha,sec); | |
1015 | ||
1016 | // 0: InFlight 1:Entering 2:Exiting | |
1017 | Int_t trkStat = 0; | |
a328fff9 | 1018 | |
1019 | // Special hits only in the drift region | |
1020 | if (drRegion) { | |
1021 | ||
1022 | // Create a track reference at the entrance and exit of each | |
1023 | // chamber that contain the momentum components of the particle | |
1024 | ||
1025 | if (gMC->IsTrackEntering()) { | |
1026 | gMC->TrackMomentum(mom); | |
1027 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber()); | |
1028 | trkStat = 1; | |
1029 | } | |
1030 | if (gMC->IsTrackExiting()) { | |
1031 | gMC->TrackMomentum(mom); | |
1032 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber()); | |
1033 | trkStat = 2; | |
1034 | } | |
1035 | ||
1036 | // Create the hits from TR photons | |
030b4415 | 1037 | if (fTR) { |
1038 | CreateTRhit(det); | |
1039 | } | |
a328fff9 | 1040 | |
1041 | } | |
1042 | ||
1043 | // Calculate the charge according to GEANT Edep | |
1044 | // Create a new dEdx hit | |
1045 | eDep = TMath::Max(gMC->Edep(),0.0) * 1.0e+09; | |
1046 | qTot = (Int_t) (eDep / kWion); | |
c4214bc0 | 1047 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 1048 | ,det |
1049 | ,hits | |
1050 | ,qTot | |
1051 | ,drRegion); | |
a328fff9 | 1052 | |
1053 | // Set Maximum Step Size | |
1054 | // Produce only one hit if Ekin is below cutoff | |
030b4415 | 1055 | if ((gMC->Etot() - gMC->TrackMass()) < kEkinMinStep) { |
1056 | return; | |
1057 | } | |
a328fff9 | 1058 | gMC->SetMaxStep(fStepSize); |
1059 | ||
1060 | } | |
1061 | ||
5c7f4665 | 1062 | //_____________________________________________________________________________ |
1063 | Double_t AliTRDv1::BetheBloch(Double_t bg) | |
1064 | { | |
1065 | // | |
1066 | // Parametrization of the Bethe-Bloch-curve | |
1067 | // The parametrization is the same as for the TPC and is taken from Lehrhaus. | |
1068 | // | |
1069 | ||
1070 | // This parameters have been adjusted to averaged values from GEANT | |
f57bb418 | 1071 | const Double_t kP1 = 7.17960e-02; |
1072 | const Double_t kP2 = 8.54196; | |
1073 | const Double_t kP3 = 1.38065e-06; | |
1074 | const Double_t kP4 = 5.30972; | |
1075 | const Double_t kP5 = 2.83798; | |
5c7f4665 | 1076 | |
f73816f5 | 1077 | // Lower cutoff of the Bethe-Bloch-curve to limit step sizes |
1078 | const Double_t kBgMin = 0.8; | |
1079 | const Double_t kBBMax = 6.83298; | |
f73816f5 | 1080 | |
1081 | if (bg > kBgMin) { | |
030b4415 | 1082 | Double_t yy = bg / TMath::Sqrt(1.0 + bg*bg); |
5c7f4665 | 1083 | Double_t aa = TMath::Power(yy,kP4); |
030b4415 | 1084 | Double_t bb = TMath::Power((1.0/bg),kP5); |
5c7f4665 | 1085 | bb = TMath::Log(kP3 + bb); |
030b4415 | 1086 | return ((kP2 - aa - bb) * kP1 / aa); |
5c7f4665 | 1087 | } |
f73816f5 | 1088 | else { |
1089 | return kBBMax; | |
1090 | } | |
d3f347ff | 1091 | |
fe4da5cc | 1092 | } |
5c7f4665 | 1093 | |
a328fff9 | 1094 | //_____________________________________________________________________________ |
c4214bc0 | 1095 | Double_t AliTRDv1::BetheBlochGeant(Double_t bg) |
a328fff9 | 1096 | { |
1097 | // | |
1098 | // Return dN/dx (number of primary collisions per centimeter) | |
1099 | // for given beta*gamma factor. | |
1100 | // | |
1101 | // Implemented by K.Oyama according to GEANT 3 parametrization shown in | |
1102 | // A.Andronic's webpage: http://www-alice.gsi.de/trd/papers/dedx/dedx.html | |
1103 | // This must be used as a set with IntSpecGeant. | |
1104 | // | |
1105 | ||
030b4415 | 1106 | Int_t i = 0; |
a328fff9 | 1107 | |
030b4415 | 1108 | Double_t arrG[20] = { 1.100000, 1.200000, 1.300000, 1.500000 |
1109 | , 1.800000, 2.000000, 2.500000, 3.000000 | |
1110 | , 4.000000, 7.000000, 10.000000, 20.000000 | |
1111 | , 40.000000, 70.000000, 100.000000, 300.000000 | |
1112 | , 600.000000, 1000.000000, 3000.000000, 10000.000000 }; | |
a328fff9 | 1113 | |
030b4415 | 1114 | Double_t arrNC[20] = { 75.009056, 45.508083, 35.299252, 27.116327 |
1115 | , 22.734999, 21.411915, 19.934095, 19.449375 | |
1116 | , 19.344431, 20.185553, 21.027925, 22.912676 | |
1117 | , 24.933352, 26.504053, 27.387468, 29.566597 | |
1118 | , 30.353779, 30.787134, 31.129285, 31.157350 }; | |
1119 | ||
1120 | // Betagamma to gamma | |
1121 | Double_t g = TMath::Sqrt(1.0 + bg*bg); | |
a328fff9 | 1122 | |
1123 | // Find the index just before the point we need. | |
030b4415 | 1124 | for (i = 0; i < 18; i++) { |
1125 | if ((arrG[i] < g) && | |
1126 | (arrG[i+1] > g)) { | |
a328fff9 | 1127 | break; |
030b4415 | 1128 | } |
1129 | } | |
a328fff9 | 1130 | |
1131 | // Simple interpolation. | |
030b4415 | 1132 | Double_t pp = ((arrNC[i+1] - arrNC[i]) / (arrG[i+1] - arrG[i])) |
1133 | * (g - arrG[i]) + arrNC[i]; | |
a328fff9 | 1134 | |
030b4415 | 1135 | return pp; |
a328fff9 | 1136 | |
1137 | } | |
1138 | ||
5c7f4665 | 1139 | //_____________________________________________________________________________ |
1140 | Double_t Ermilova(Double_t *x, Double_t *) | |
1141 | { | |
1142 | // | |
1143 | // Calculates the delta-ray energy distribution according to Ermilova. | |
1144 | // Logarithmic scale ! | |
1145 | // | |
1146 | ||
1147 | Double_t energy; | |
1148 | Double_t dpos; | |
1149 | Double_t dnde; | |
1150 | ||
030b4415 | 1151 | Int_t pos1; |
1152 | Int_t pos2; | |
5c7f4665 | 1153 | |
8230f242 | 1154 | const Int_t kNv = 31; |
5c7f4665 | 1155 | |
030b4415 | 1156 | Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120 |
1157 | , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052 | |
1158 | , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915 | |
1159 | , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009 | |
1160 | , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103 | |
1161 | , 9.4727, 9.9035, 10.3735, 10.5966, 10.8198 | |
1162 | , 11.5129 }; | |
1163 | ||
1164 | Float_t vye[kNv] = { 80.0, 31.0, 23.3, 21.1, 21.0 | |
1165 | , 20.9, 20.8, 20.0, 16.0, 11.0 | |
1166 | , 8.0, 6.0, 5.2, 4.6, 4.0 | |
1167 | , 3.5, 3.0, 1.4, 0.67, 0.44 | |
1168 | , 0.3, 0.18, 0.12, 0.08, 0.056 | |
1169 | , 0.04, 0.023, 0.015, 0.011, 0.01 | |
1170 | , 0.004 }; | |
5c7f4665 | 1171 | |
1172 | energy = x[0]; | |
1173 | ||
1174 | // Find the position | |
030b4415 | 1175 | pos1 = 0; |
1176 | pos2 = 0; | |
5c7f4665 | 1177 | dpos = 0; |
1178 | do { | |
1179 | dpos = energy - vxe[pos2++]; | |
1180 | } | |
1181 | while (dpos > 0); | |
1182 | pos2--; | |
030b4415 | 1183 | if (pos2 > kNv) { |
1184 | pos2 = kNv - 1; | |
1185 | } | |
5c7f4665 | 1186 | pos1 = pos2 - 1; |
1187 | ||
1188 | // Differentiate between the sampling points | |
1189 | dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]); | |
1190 | ||
1191 | return dnde; | |
1192 | ||
1193 | } | |
a328fff9 | 1194 | |
1195 | //_____________________________________________________________________________ | |
1196 | Double_t IntSpecGeant(Double_t *x, Double_t *) | |
1197 | { | |
1198 | // | |
1199 | // Integrated spectrum from Geant3 | |
1200 | // | |
1201 | ||
96efaf83 | 1202 | const Int_t npts = 83; |
030b4415 | 1203 | Double_t arre[npts] = { 2.421257, 2.483278, 2.534301, 2.592230 |
1204 | , 2.672067, 2.813299, 3.015059, 3.216819 | |
1205 | , 3.418579, 3.620338, 3.868209, 3.920198 | |
1206 | , 3.978284, 4.063923, 4.186264, 4.308605 | |
1207 | , 4.430946, 4.553288, 4.724261, 4.837736 | |
1208 | , 4.999842, 5.161949, 5.324056, 5.486163 | |
1209 | , 5.679688, 5.752998, 5.857728, 5.962457 | |
1210 | , 6.067185, 6.171914, 6.315653, 6.393674 | |
1211 | , 6.471694, 6.539689, 6.597658, 6.655627 | |
1212 | , 6.710957, 6.763648, 6.816338, 6.876198 | |
1213 | , 6.943227, 7.010257, 7.106285, 7.252151 | |
1214 | , 7.460531, 7.668911, 7.877290, 8.085670 | |
1215 | , 8.302979, 8.353585, 8.413120, 8.483500 | |
1216 | , 8.541030, 8.592857, 8.668865, 8.820485 | |
1217 | , 9.037086, 9.253686, 9.470286, 9.686887 | |
1218 | , 9.930838, 9.994655, 10.085822, 10.176990 | |
1219 | , 10.268158, 10.359325, 10.503614, 10.627565 | |
1220 | , 10.804637, 10.981709, 11.158781, 11.335854 | |
1221 | , 11.593397, 11.781165, 12.049404, 12.317644 | |
1222 | , 12.585884, 12.854123, 14.278421, 16.975889 | |
1223 | , 20.829416, 24.682943, 28.536469 }; | |
1224 | ||
1225 | Double_t arrdnde[npts] = { 10.960000, 10.960000, 10.359500, 9.811340 | |
1226 | , 9.1601500, 8.206670, 6.919630, 5.655430 | |
1227 | , 4.6221300, 3.777610, 3.019560, 2.591950 | |
1228 | , 2.5414600, 2.712920, 3.327460, 4.928240 | |
1229 | , 7.6185300, 10.966700, 12.225800, 8.094750 | |
1230 | , 3.3586900, 1.553650, 1.209600, 1.263840 | |
1231 | , 1.3241100, 1.312140, 1.255130, 1.165770 | |
1232 | , 1.0594500, 0.945450, 0.813231, 0.699837 | |
1233 | , 0.6235580, 2.260990, 2.968350, 2.240320 | |
1234 | , 1.7988300, 1.553300, 1.432070, 1.535520 | |
1235 | , 1.4429900, 1.247990, 1.050750, 0.829549 | |
1236 | , 0.5900280, 0.395897, 0.268741, 0.185320 | |
1237 | , 0.1292120, 0.103545, 0.0949525, 0.101535 | |
1238 | , 0.1276380, 0.134216, 0.123816, 0.104557 | |
1239 | , 0.0751843, 0.0521745, 0.0373546, 0.0275391 | |
1240 | , 0.0204713, 0.0169234, 0.0154552, 0.0139194 | |
1241 | , 0.0125592, 0.0113638, 0.0107354, 0.0102137 | |
1242 | , 0.00845984, 0.00683338, 0.00556836, 0.00456874 | |
1243 | , 0.0036227, 0.00285991, 0.00226664, 0.00172234 | |
1244 | , 0.00131226, 0.00100284, 0.000465492, 7.26607e-05 | |
1245 | , 3.63304e-06, 0.0000000, 0.0000000 }; | |
1246 | ||
1247 | Int_t i; | |
a328fff9 | 1248 | Double_t energy = x[0]; |
a328fff9 | 1249 | |
030b4415 | 1250 | for (i = 0; i < npts; i++) { |
1251 | if (energy < arre[i]) { | |
1252 | break; | |
1253 | } | |
1254 | } | |
a328fff9 | 1255 | |
030b4415 | 1256 | if (i == 0) { |
1257 | AliErrorGeneral("AliTRDv1::IntSpecGeant","Given energy value is too small or zero"); | |
1258 | } | |
a328fff9 | 1259 | |
f57bb418 | 1260 | return arrdnde[i]; |
a328fff9 | 1261 | |
1262 | } |