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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> |
268f57b1 | 33 | #include <TGeoMatrix.h> |
170c35f1 | 34 | #include <TGeoPhysicalNode.h> |
fe4da5cc | 35 | |
d3f347ff | 36 | #include "AliConst.h" |
45160b1f | 37 | #include "AliLog.h" |
e6add757 | 38 | #include "AliTrackReference.h" |
45160b1f | 39 | #include "AliMC.h" |
88cb7938 | 40 | #include "AliRun.h" |
030b4415 | 41 | |
88cb7938 | 42 | #include "AliTRDgeometry.h" |
793ff80c | 43 | #include "AliTRDhit.h" |
cb2f9e9b | 44 | #include "AliTRDsimTR.h" |
88cb7938 | 45 | #include "AliTRDv1.h" |
851d3db9 | 46 | |
fe4da5cc | 47 | ClassImp(AliTRDv1) |
8230f242 | 48 | |
49 | //_____________________________________________________________________________ | |
030b4415 | 50 | AliTRDv1::AliTRDv1() |
51 | :AliTRD() | |
52 | ,fTRon(kFALSE) | |
53 | ,fTR(NULL) | |
54 | ,fTypeOfStepManager(0) | |
55 | ,fStepSize(0) | |
56 | ,fDeltaE(NULL) | |
57 | ,fDeltaG(NULL) | |
58 | ,fTrackLength0(0) | |
59 | ,fPrimaryTrackPid(0) | |
8230f242 | 60 | { |
61 | // | |
62 | // Default constructor | |
63 | // | |
64 | ||
8230f242 | 65 | } |
66 | ||
fe4da5cc | 67 | //_____________________________________________________________________________ |
68 | AliTRDv1::AliTRDv1(const char *name, const char *title) | |
030b4415 | 69 | :AliTRD(name,title) |
70 | ,fTRon(kTRUE) | |
71 | ,fTR(NULL) | |
67c47633 | 72 | ,fTypeOfStepManager(2) |
030b4415 | 73 | ,fStepSize(0.1) |
74 | ,fDeltaE(NULL) | |
75 | ,fDeltaG(NULL) | |
76 | ,fTrackLength0(0) | |
77 | ,fPrimaryTrackPid(0) | |
fe4da5cc | 78 | { |
79 | // | |
851d3db9 | 80 | // Standard constructor for Transition Radiation Detector version 1 |
fe4da5cc | 81 | // |
82bbf98a | 82 | |
5c7f4665 | 83 | SetBufferSize(128000); |
84 | ||
85 | } | |
86 | ||
87 | //_____________________________________________________________________________ | |
88 | AliTRDv1::~AliTRDv1() | |
89 | { | |
dd9a6ee3 | 90 | // |
91 | // AliTRDv1 destructor | |
92 | // | |
82bbf98a | 93 | |
030b4415 | 94 | if (fDeltaE) { |
95 | delete fDeltaE; | |
96 | fDeltaE = 0; | |
97 | } | |
98 | ||
99 | if (fDeltaG) { | |
100 | delete fDeltaG; | |
101 | fDeltaG = 0; | |
102 | } | |
103 | ||
104 | if (fTR) { | |
105 | delete fTR; | |
106 | fTR = 0; | |
107 | } | |
82bbf98a | 108 | |
fe4da5cc | 109 | } |
110 | ||
f57bb418 | 111 | //_____________________________________________________________________________ |
112 | void AliTRDv1::AddAlignableVolumes() const | |
113 | { | |
114 | // | |
115 | // Create entries for alignable volumes associating the symbolic volume | |
116 | // name with the corresponding volume path. Needs to be syncronized with | |
117 | // eventual changes in the geometry. | |
118 | // | |
119 | ||
120 | TString volPath; | |
121 | TString symName; | |
122 | ||
92cd97ad | 123 | TString vpStr = "ALIC_1/B077_1/BSEGMO"; |
124 | TString vpApp1 = "_1/BTRD"; | |
125 | TString vpApp2 = "_1"; | |
126 | TString vpApp3a = "/UTR1_1/UTS1_1/UTI1_1/UT"; | |
127 | TString vpApp3b = "/UTR2_1/UTS2_1/UTI2_1/UT"; | |
128 | TString vpApp3c = "/UTR3_1/UTS3_1/UTI3_1/UT"; | |
f57bb418 | 129 | |
92cd97ad | 130 | TString snStr = "TRD/sm"; |
131 | TString snApp1 = "/st"; | |
132 | TString snApp2 = "/pl"; | |
f57bb418 | 133 | |
134 | // | |
135 | // The super modules | |
136 | // The symbolic names are: TRD/sm00 | |
137 | // ... | |
138 | // TRD/sm17 | |
139 | // | |
140 | for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) { | |
141 | ||
142 | volPath = vpStr; | |
143 | volPath += isect; | |
144 | volPath += vpApp1; | |
145 | volPath += isect; | |
146 | volPath += vpApp2; | |
147 | ||
148 | symName = snStr; | |
149 | symName += Form("%02d",isect); | |
150 | ||
151 | gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data()); | |
152 | ||
153 | } | |
154 | ||
155 | // | |
156 | // The readout chambers | |
157 | // The symbolic names are: TRD/sm00/st0/pl0 | |
158 | // ... | |
159 | // TRD/sm17/st4/pl5 | |
160 | // | |
161 | for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) { | |
8bf0cd64 | 162 | |
163 | if (fGeometry->GetSMstatus(isect) == 0) continue; | |
164 | ||
f57bb418 | 165 | for (Int_t icham = 0; icham < AliTRDgeometry::Ncham(); icham++) { |
166 | for (Int_t iplan = 0; iplan < AliTRDgeometry::Nplan(); iplan++) { | |
167 | ||
168 | Int_t idet = AliTRDgeometry::GetDetectorSec(iplan,icham); | |
169 | ||
170 | volPath = vpStr; | |
171 | volPath += isect; | |
172 | volPath += vpApp1; | |
173 | volPath += isect; | |
174 | volPath += vpApp2; | |
92cd97ad | 175 | switch (isect) { |
176 | case 13: | |
177 | case 14: | |
178 | case 15: | |
179 | if (icham == 2) { | |
180 | continue; | |
181 | } | |
182 | volPath += vpApp3c; | |
183 | break; | |
184 | case 11: | |
185 | case 12: | |
186 | volPath += vpApp3b; | |
187 | break; | |
188 | default: | |
189 | volPath += vpApp3a; | |
190 | }; | |
f57bb418 | 191 | volPath += Form("%02d",idet); |
192 | volPath += vpApp2; | |
193 | ||
194 | symName = snStr; | |
195 | symName += Form("%02d",isect); | |
196 | symName += snApp1; | |
197 | symName += icham; | |
198 | symName += snApp2; | |
199 | symName += iplan; | |
200 | ||
51a5f1d0 | 201 | TGeoPNEntry *alignableEntry = |
202 | gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data()); | |
f57bb418 | 203 | |
170c35f1 | 204 | // Add the tracking to local matrix following the TPC example |
51a5f1d0 | 205 | if (alignableEntry) { |
206 | const char *path = alignableEntry->GetTitle(); | |
207 | if (!gGeoManager->cd(path)) { | |
208 | AliFatal(Form("Volume path %s not valid!",path)); | |
209 | } | |
92cd97ad | 210 | // Is this correct still???? |
51a5f1d0 | 211 | TGeoHMatrix *globMatrix = gGeoManager->GetCurrentMatrix(); |
212 | Double_t sectorAngle = 20.0 * (isect % 18) + 10.0; | |
213 | TGeoHMatrix *t2lMatrix = new TGeoHMatrix(); | |
214 | t2lMatrix->RotateZ(sectorAngle); | |
215 | t2lMatrix->MultiplyLeft(&(globMatrix->Inverse())); | |
216 | alignableEntry->SetMatrix(t2lMatrix); | |
217 | } | |
218 | else { | |
219 | AliError(Form("Alignable entry %s is not valid!",symName.Data())); | |
220 | } | |
8bf0cd64 | 221 | |
f57bb418 | 222 | } |
223 | } | |
224 | } | |
225 | ||
226 | } | |
227 | ||
fe4da5cc | 228 | //_____________________________________________________________________________ |
229 | void AliTRDv1::CreateGeometry() | |
230 | { | |
231 | // | |
851d3db9 | 232 | // Create the GEANT geometry for the Transition Radiation Detector - Version 1 |
5c7f4665 | 233 | // This version covers the full azimuth. |
d3f347ff | 234 | // |
235 | ||
82bbf98a | 236 | // Check that FRAME is there otherwise we have no place where to put the TRD |
8230f242 | 237 | AliModule* frame = gAlice->GetModule("FRAME"); |
030b4415 | 238 | if (!frame) { |
239 | AliError("TRD needs FRAME to be present\n"); | |
240 | return; | |
241 | } | |
d3f347ff | 242 | |
82bbf98a | 243 | // Define the chambers |
244 | AliTRD::CreateGeometry(); | |
d3f347ff | 245 | |
fe4da5cc | 246 | } |
247 | ||
248 | //_____________________________________________________________________________ | |
249 | void AliTRDv1::CreateMaterials() | |
250 | { | |
251 | // | |
851d3db9 | 252 | // Create materials for the Transition Radiation Detector version 1 |
fe4da5cc | 253 | // |
82bbf98a | 254 | |
d3f347ff | 255 | AliTRD::CreateMaterials(); |
82bbf98a | 256 | |
fe4da5cc | 257 | } |
258 | ||
793ff80c | 259 | //_____________________________________________________________________________ |
260 | void AliTRDv1::CreateTRhit(Int_t det) | |
261 | { | |
262 | // | |
263 | // Creates an electron cluster from a TR photon. | |
264 | // The photon is assumed to be created a the end of the radiator. The | |
265 | // distance after which it deposits its energy takes into account the | |
266 | // absorbtion of the entrance window and of the gas mixture in drift | |
267 | // volume. | |
268 | // | |
269 | ||
793ff80c | 270 | // Ionization energy |
bc327ce2 | 271 | const Float_t kWion = 23.53; |
793ff80c | 272 | |
273 | // Maximum number of TR photons per track | |
274 | const Int_t kNTR = 50; | |
275 | ||
030b4415 | 276 | TLorentzVector mom; |
277 | TLorentzVector pos; | |
793ff80c | 278 | |
ce0d6231 | 279 | Float_t eTR[kNTR]; |
280 | Int_t nTR; | |
793ff80c | 281 | |
ce0d6231 | 282 | // Create TR photons |
283 | gMC->TrackMomentum(mom); | |
284 | Float_t pTot = mom.Rho(); | |
285 | fTR->CreatePhotons(11,pTot,nTR,eTR); | |
286 | if (nTR > kNTR) { | |
287 | AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR)); | |
288 | } | |
f73816f5 | 289 | |
ce0d6231 | 290 | // Loop through the TR photons |
291 | for (Int_t iTR = 0; iTR < nTR; iTR++) { | |
793ff80c | 292 | |
ce0d6231 | 293 | Float_t energyMeV = eTR[iTR] * 0.001; |
294 | Float_t energyeV = eTR[iTR] * 1000.0; | |
295 | Float_t absLength = 0.0; | |
296 | Float_t sigma = 0.0; | |
793ff80c | 297 | |
ce0d6231 | 298 | // Take the absorbtion in the entrance window into account |
299 | Double_t muMy = fTR->GetMuMy(energyMeV); | |
300 | sigma = muMy * fFoilDensity; | |
301 | if (sigma > 0.0) { | |
302 | absLength = gRandom->Exp(1.0/sigma); | |
303 | if (absLength < AliTRDgeometry::MyThick()) { | |
842287f2 | 304 | continue; |
305 | } | |
ce0d6231 | 306 | } |
307 | else { | |
308 | continue; | |
309 | } | |
793ff80c | 310 | |
ce0d6231 | 311 | // The absorbtion cross sections in the drift gas |
312 | // Gas-mixture (Xe/CO2) | |
313 | Double_t muXe = fTR->GetMuXe(energyMeV); | |
314 | Double_t muCO = fTR->GetMuCO(energyMeV); | |
315 | sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity * fTR->GetTemp(); | |
316 | ||
317 | // The distance after which the energy of the TR photon | |
318 | // is deposited. | |
319 | if (sigma > 0.0) { | |
320 | absLength = gRandom->Exp(1.0/sigma); | |
321 | if (absLength > (AliTRDgeometry::DrThick() | |
322 | + AliTRDgeometry::AmThick())) { | |
842287f2 | 323 | continue; |
324 | } | |
ce0d6231 | 325 | } |
326 | else { | |
327 | continue; | |
328 | } | |
793ff80c | 329 | |
ce0d6231 | 330 | // The position of the absorbtion |
331 | Float_t posHit[3]; | |
332 | gMC->TrackPosition(pos); | |
333 | posHit[0] = pos[0] + mom[0] / pTot * absLength; | |
334 | posHit[1] = pos[1] + mom[1] / pTot * absLength; | |
335 | posHit[2] = pos[2] + mom[2] / pTot * absLength; | |
793ff80c | 336 | |
ce0d6231 | 337 | // Create the charge |
338 | Int_t q = ((Int_t) (energyeV / kWion)); | |
793ff80c | 339 | |
ce0d6231 | 340 | // Add the hit to the array. TR photon hits are marked |
341 | // by negative charge | |
342 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() | |
343 | ,det | |
344 | ,posHit | |
345 | ,-q | |
25ca55ce | 346 | ,gMC->TrackTime()*1.0e06 |
d4c6453d | 347 | ,kTRUE); |
793ff80c | 348 | |
349 | } | |
350 | ||
351 | } | |
352 | ||
5c7f4665 | 353 | //_____________________________________________________________________________ |
354 | void AliTRDv1::Init() | |
355 | { | |
356 | // | |
357 | // Initialise Transition Radiation Detector after geometry has been built. | |
5c7f4665 | 358 | // |
359 | ||
360 | AliTRD::Init(); | |
361 | ||
45160b1f | 362 | AliDebug(1,"Slow simulator\n"); |
bd0f8685 | 363 | |
364 | // Switch on TR simulation as default | |
365 | if (!fTRon) { | |
45160b1f | 366 | AliInfo("TR simulation off"); |
bd0f8685 | 367 | } |
368 | else { | |
cb2f9e9b | 369 | fTR = new AliTRDsimTR(); |
bd0f8685 | 370 | } |
5c7f4665 | 371 | |
372 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) | |
373 | const Float_t kPoti = 12.1; | |
374 | // Maximum energy (50 keV); | |
375 | const Float_t kEend = 50000.0; | |
376 | // Ermilova distribution for the delta-ray spectrum | |
030b4415 | 377 | Float_t poti = TMath::Log(kPoti); |
378 | Float_t eEnd = TMath::Log(kEend); | |
a328fff9 | 379 | |
380 | // Ermilova distribution for the delta-ray spectrum | |
c4214bc0 | 381 | fDeltaE = new TF1("deltae" ,Ermilova ,poti,eEnd,0); |
a328fff9 | 382 | |
383 | // Geant3 distribution for the delta-ray spectrum | |
c4214bc0 | 384 | fDeltaG = new TF1("deltag",IntSpecGeant,2.421257,28.536469,0); |
5c7f4665 | 385 | |
45160b1f | 386 | AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); |
5c7f4665 | 387 | |
fe4da5cc | 388 | } |
389 | ||
5c7f4665 | 390 | //_____________________________________________________________________________ |
391 | void AliTRDv1::StepManager() | |
a328fff9 | 392 | { |
393 | // | |
c4214bc0 | 394 | // Slow simulator. Every charged track produces electron cluster as hits |
a328fff9 | 395 | // along its path across the drift volume. |
396 | // | |
397 | ||
398 | switch (fTypeOfStepManager) { | |
a6dd11e9 | 399 | case 0: |
400 | StepManagerErmilova(); | |
401 | break; | |
402 | case 1: | |
403 | StepManagerGeant(); | |
404 | break; | |
405 | case 2: | |
406 | StepManagerFixedStep(); | |
407 | break; | |
408 | default: | |
409 | AliWarning("Not a valid Step Manager."); | |
a328fff9 | 410 | } |
411 | ||
412 | } | |
413 | ||
414 | //_____________________________________________________________________________ | |
415 | void AliTRDv1::SelectStepManager(Int_t t) | |
416 | { | |
417 | // | |
418 | // Selects a step manager type: | |
419 | // 0 - Ermilova | |
420 | // 1 - Geant3 | |
421 | // 2 - Fixed step size | |
422 | // | |
423 | ||
a328fff9 | 424 | fTypeOfStepManager = t; |
45160b1f | 425 | AliInfo(Form("Step Manager type %d was selected",fTypeOfStepManager)); |
a328fff9 | 426 | |
427 | } | |
428 | ||
429 | //_____________________________________________________________________________ | |
430 | void AliTRDv1::StepManagerGeant() | |
431 | { | |
432 | // | |
c4214bc0 | 433 | // Slow simulator. Every charged track produces electron cluster as hits |
a328fff9 | 434 | // along its path across the drift volume. The step size is set acording |
435 | // to Bethe-Bloch. The energy distribution of the delta electrons follows | |
436 | // a spectrum taken from Geant3. | |
437 | // | |
f2e3a0b5 | 438 | // Version by A. Bercuci |
439 | // | |
440 | ||
c4214bc0 | 441 | Int_t pla = 0; |
442 | Int_t cha = 0; | |
443 | Int_t sec = 0; | |
444 | Int_t det = 0; | |
445 | Int_t iPdg; | |
446 | Int_t qTot; | |
447 | ||
448 | Float_t hits[3]; | |
449 | Float_t charge; | |
450 | Float_t aMass; | |
451 | ||
030b4415 | 452 | Double_t pTot = 0; |
c4214bc0 | 453 | Double_t eDelta; |
030b4415 | 454 | Double_t betaGamma; |
455 | Double_t pp; | |
f2e3a0b5 | 456 | Double_t stepSize = 0; |
c4214bc0 | 457 | |
458 | Bool_t drRegion = kFALSE; | |
459 | Bool_t amRegion = kFALSE; | |
460 | ||
2c8bf4aa | 461 | TString cIdPath; |
462 | Char_t cIdSector[3]; | |
463 | cIdSector[2] = 0; | |
464 | ||
c4214bc0 | 465 | TString cIdCurrent; |
466 | TString cIdSensDr = "J"; | |
467 | TString cIdSensAm = "K"; | |
468 | Char_t cIdChamber[3]; | |
469 | cIdChamber[2] = 0; | |
470 | ||
030b4415 | 471 | TLorentzVector pos; |
472 | TLorentzVector mom; | |
c4214bc0 | 473 | |
030b4415 | 474 | TArrayI processes; |
f2e3a0b5 | 475 | |
c4214bc0 | 476 | const Int_t kNplan = AliTRDgeometry::Nplan(); |
477 | const Int_t kNcham = AliTRDgeometry::Ncham(); | |
478 | const Int_t kNdetsec = kNplan * kNcham; | |
479 | ||
030b4415 | 480 | const Double_t kBig = 1.0e+12; // Infinitely big |
bc327ce2 | 481 | const Float_t kWion = 23.53; // Ionization energy |
c4214bc0 | 482 | const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g |
483 | ||
484 | // Minimum energy for the step size adjustment | |
485 | const Float_t kEkinMinStep = 1.0e-5; | |
486 | // energy threshold for production of delta electrons | |
f2e3a0b5 | 487 | const Float_t kECut = 1.0e4; |
488 | // Parameters entering the parametrized range for delta electrons | |
030b4415 | 489 | const Float_t kRa = 5.37e-4; |
f2e3a0b5 | 490 | const Float_t kRb = 0.9815; |
030b4415 | 491 | const Float_t kRc = 3.123e-3; |
f2e3a0b5 | 492 | // Gas density -> To be made user adjustable ! |
030b4415 | 493 | // [0.85*0.00549+0.15*0.00186 (Xe-CO2 85-15)] |
494 | const Float_t kRho = 0.004945 ; | |
a328fff9 | 495 | |
c4214bc0 | 496 | // Plateau value of the energy-loss for electron in xenon |
030b4415 | 497 | // The averaged value (26/3/99) |
c4214bc0 | 498 | const Float_t kPlateau = 1.55; |
030b4415 | 499 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) |
500 | const Float_t kPrim = 19.34; | |
c4214bc0 | 501 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) |
502 | const Float_t kPoti = 12.1; | |
030b4415 | 503 | // PDG code electron |
504 | const Int_t kPdgElectron = 11; | |
c4214bc0 | 505 | |
506 | // Set the maximum step size to a very large number for all | |
507 | // neutral particles and those outside the driftvolume | |
508 | gMC->SetMaxStep(kBig); | |
509 | ||
510 | // Use only charged tracks | |
511 | if (( gMC->TrackCharge() ) && | |
c4214bc0 | 512 | (!gMC->IsTrackDisappeared())) { |
513 | ||
514 | // Inside a sensitive volume? | |
515 | drRegion = kFALSE; | |
516 | amRegion = kFALSE; | |
517 | cIdCurrent = gMC->CurrentVolName(); | |
518 | if (cIdSensDr == cIdCurrent[1]) { | |
519 | drRegion = kTRUE; | |
520 | } | |
521 | if (cIdSensAm == cIdCurrent[1]) { | |
522 | amRegion = kTRUE; | |
523 | } | |
524 | if (drRegion || amRegion) { | |
a328fff9 | 525 | |
c4214bc0 | 526 | // The hit coordinates and charge |
527 | gMC->TrackPosition(pos); | |
528 | hits[0] = pos[0]; | |
529 | hits[1] = pos[1]; | |
530 | hits[2] = pos[2]; | |
531 | ||
2c8bf4aa | 532 | // The sector number (0 - 17), according to standard coordinate system |
533 | cIdPath = gGeoManager->GetPath(); | |
534 | cIdSector[0] = cIdPath[21]; | |
535 | cIdSector[1] = cIdPath[22]; | |
536 | sec = atoi(cIdSector); | |
c4214bc0 | 537 | |
538 | // The plane and chamber number | |
030b4415 | 539 | cIdChamber[0] = cIdCurrent[2]; |
540 | cIdChamber[1] = cIdCurrent[3]; | |
c4214bc0 | 541 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
8a497c18 | 542 | cha = ((Int_t) idChamber / kNplan); |
c4214bc0 | 543 | pla = ((Int_t) idChamber % kNplan); |
544 | ||
ce0d6231 | 545 | // The detector number |
546 | det = fGeometry->GetDetector(pla,cha,sec); | |
c4214bc0 | 547 | |
ce0d6231 | 548 | // Special hits only in the drift region |
549 | if ((drRegion) && | |
550 | (gMC->IsTrackEntering())) { | |
c4214bc0 | 551 | |
ce0d6231 | 552 | // Create a track reference at the entrance of each |
553 | // chamber that contains the momentum components of the particle | |
554 | gMC->TrackMomentum(mom); | |
e6add757 | 555 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
c4214bc0 | 556 | |
ce0d6231 | 557 | // Create the hits from TR photons if electron/positron is |
558 | // entering the drift volume | |
559 | if ((fTR) && | |
560 | (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) { | |
561 | CreateTRhit(det); | |
562 | } | |
f2e3a0b5 | 563 | |
ce0d6231 | 564 | } |
565 | else if ((amRegion) && | |
566 | (gMC->IsTrackExiting())) { | |
f2e3a0b5 | 567 | |
ce0d6231 | 568 | // Create a track reference at the exit of each |
569 | // chamber that contains the momentum components of the particle | |
570 | gMC->TrackMomentum(mom); | |
e6add757 | 571 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
c4214bc0 | 572 | |
ce0d6231 | 573 | } |
c4214bc0 | 574 | |
ce0d6231 | 575 | // Calculate the energy of the delta-electrons |
576 | // modified by Alex Bercuci (A.Bercuci@gsi.de) on 26.01.06 | |
577 | // take into account correlation with the underlying GEANT tracking | |
578 | // mechanism. see | |
579 | // http://www-linux.gsi.de/~abercuci/Contributions/TRD/index.html | |
580 | // | |
581 | // determine the most significant process (last on the processes list) | |
582 | // which caused this hit | |
583 | gMC->StepProcesses(processes); | |
584 | Int_t nofprocesses = processes.GetSize(); | |
585 | Int_t pid; | |
586 | if (!nofprocesses) { | |
587 | pid = 0; | |
588 | } | |
589 | else { | |
590 | pid = processes[nofprocesses-1]; | |
591 | } | |
f2e3a0b5 | 592 | |
ce0d6231 | 593 | // Generate Edep according to GEANT parametrisation |
594 | eDelta = TMath::Exp(fDeltaG->GetRandom()) - kPoti; | |
595 | eDelta = TMath::Max(eDelta,0.0); | |
596 | Float_t prRange = 0.0; | |
597 | Float_t range = gMC->TrackLength() - fTrackLength0; | |
598 | // merge GEANT tracker information with locally cooked one | |
599 | if (gAlice->GetMCApp()->GetCurrentTrackNumber() == fPrimaryTrackPid) { | |
600 | if (pid == 27) { | |
601 | if (eDelta >= kECut) { | |
602 | prRange = kRa * eDelta * 0.001 | |
603 | * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho; | |
604 | if (prRange >= (3.7 - range)) { | |
605 | eDelta *= 0.1; | |
606 | } | |
607 | } | |
608 | } | |
609 | else if (pid == 1) { | |
610 | if (eDelta < kECut) { | |
611 | eDelta *= 0.5; | |
612 | } | |
613 | else { | |
614 | prRange = kRa * eDelta * 0.001 | |
615 | * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho; | |
616 | if (prRange >= ((AliTRDgeometry::DrThick() | |
617 | + AliTRDgeometry::AmThick()) - range)) { | |
618 | eDelta *= 0.05; | |
619 | } | |
620 | else { | |
f2e3a0b5 | 621 | eDelta *= 0.5; |
ce0d6231 | 622 | } |
623 | } | |
624 | } | |
f2e3a0b5 | 625 | else { |
626 | eDelta = 0.0; | |
ce0d6231 | 627 | } |
628 | } | |
629 | else { | |
630 | eDelta = 0.0; | |
631 | } | |
c4214bc0 | 632 | |
ce0d6231 | 633 | // Generate the electron cluster size |
634 | if (eDelta > 0.0) { | |
f2e3a0b5 | 635 | |
ce0d6231 | 636 | qTot = ((Int_t) (eDelta / kWion) + 1); |
637 | ||
638 | // Create a new dEdx hit | |
030b4415 | 639 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
640 | ,det | |
641 | ,hits | |
642 | ,qTot | |
25ca55ce | 643 | ,gMC->TrackTime()*1.0e06 |
030b4415 | 644 | ,drRegion); |
c4214bc0 | 645 | |
ce0d6231 | 646 | } |
647 | ||
648 | // Calculate the maximum step size for the next tracking step | |
649 | // Produce only one hit if Ekin is below cutoff | |
650 | aMass = gMC->TrackMass(); | |
651 | if ((gMC->Etot() - aMass) > kEkinMinStep) { | |
652 | ||
653 | // The energy loss according to Bethe Bloch | |
654 | iPdg = TMath::Abs(gMC->TrackPid()); | |
655 | if ((iPdg != kPdgElectron) || | |
656 | ((iPdg == kPdgElectron) && | |
657 | (pTot < kPTotMaxEl))) { | |
658 | gMC->TrackMomentum(mom); | |
659 | pTot = mom.Rho(); | |
660 | betaGamma = pTot / aMass; | |
661 | pp = BetheBlochGeant(betaGamma); | |
662 | // Take charge > 1 into account | |
663 | charge = gMC->TrackCharge(); | |
664 | if (TMath::Abs(charge) > 1) { | |
665 | pp = pp * charge*charge; | |
666 | } | |
667 | } | |
668 | else { | |
669 | // Electrons above 20 Mev/c are at the plateau | |
670 | pp = kPrim * kPlateau; | |
671 | } | |
f2e3a0b5 | 672 | |
ce0d6231 | 673 | Int_t nsteps = 0; |
674 | do { | |
675 | nsteps = gRandom->Poisson(pp); | |
676 | } while(!nsteps); | |
677 | stepSize = 1.0 / nsteps; | |
678 | gMC->SetMaxStep(stepSize); | |
f2e3a0b5 | 679 | |
c4214bc0 | 680 | } |
f2e3a0b5 | 681 | |
c4214bc0 | 682 | } |
f2e3a0b5 | 683 | |
c4214bc0 | 684 | } |
f2e3a0b5 | 685 | |
a328fff9 | 686 | } |
687 | ||
688 | //_____________________________________________________________________________ | |
689 | void AliTRDv1::StepManagerErmilova() | |
5c7f4665 | 690 | { |
691 | // | |
5c7f4665 | 692 | // Slow simulator. Every charged track produces electron cluster as hits |
693 | // along its path across the drift volume. The step size is set acording | |
694 | // to Bethe-Bloch. The energy distribution of the delta electrons follows | |
695 | // a spectrum taken from Ermilova et al. | |
696 | // | |
697 | ||
851d3db9 | 698 | Int_t pla = 0; |
699 | Int_t cha = 0; | |
700 | Int_t sec = 0; | |
793ff80c | 701 | Int_t det = 0; |
851d3db9 | 702 | Int_t iPdg; |
793ff80c | 703 | Int_t qTot; |
5c7f4665 | 704 | |
793ff80c | 705 | Float_t hits[3]; |
a5cadd36 | 706 | Double_t random[1]; |
5c7f4665 | 707 | Float_t charge; |
708 | Float_t aMass; | |
709 | ||
030b4415 | 710 | Double_t pTot = 0.0; |
5c7f4665 | 711 | Double_t eDelta; |
030b4415 | 712 | Double_t betaGamma; |
713 | Double_t pp; | |
f73816f5 | 714 | Double_t stepSize; |
5c7f4665 | 715 | |
332e9569 | 716 | Bool_t drRegion = kFALSE; |
717 | Bool_t amRegion = kFALSE; | |
718 | ||
2c8bf4aa | 719 | TString cIdPath; |
720 | Char_t cIdSector[3]; | |
721 | cIdSector[2] = 0; | |
722 | ||
332e9569 | 723 | TString cIdCurrent; |
724 | TString cIdSensDr = "J"; | |
725 | TString cIdSensAm = "K"; | |
593a9fc3 | 726 | Char_t cIdChamber[3]; |
727 | cIdChamber[2] = 0; | |
332e9569 | 728 | |
030b4415 | 729 | TLorentzVector pos; |
730 | TLorentzVector mom; | |
82bbf98a | 731 | |
332e9569 | 732 | const Int_t kNplan = AliTRDgeometry::Nplan(); |
e644678a | 733 | const Int_t kNcham = AliTRDgeometry::Ncham(); |
734 | const Int_t kNdetsec = kNplan * kNcham; | |
735 | ||
030b4415 | 736 | const Double_t kBig = 1.0e+12; // Infinitely big |
bc327ce2 | 737 | const Float_t kWion = 23.53; // Ionization energy |
a328fff9 | 738 | const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g |
5c7f4665 | 739 | |
f73816f5 | 740 | // Minimum energy for the step size adjustment |
741 | const Float_t kEkinMinStep = 1.0e-5; | |
a328fff9 | 742 | |
5c7f4665 | 743 | // Plateau value of the energy-loss for electron in xenon |
030b4415 | 744 | // The averaged value (26/3/99) |
a3c76cdc | 745 | const Float_t kPlateau = 1.55; |
030b4415 | 746 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) |
747 | const Float_t kPrim = 48.0; | |
5c7f4665 | 748 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) |
a3c76cdc | 749 | const Float_t kPoti = 12.1; |
030b4415 | 750 | // PDG code electron |
751 | const Int_t kPdgElectron = 11; | |
5c7f4665 | 752 | |
753 | // Set the maximum step size to a very large number for all | |
754 | // neutral particles and those outside the driftvolume | |
755 | gMC->SetMaxStep(kBig); | |
756 | ||
757 | // Use only charged tracks | |
758 | if (( gMC->TrackCharge() ) && | |
5c7f4665 | 759 | (!gMC->IsTrackDisappeared())) { |
fe4da5cc | 760 | |
5c7f4665 | 761 | // Inside a sensitive volume? |
332e9569 | 762 | drRegion = kFALSE; |
763 | amRegion = kFALSE; | |
764 | cIdCurrent = gMC->CurrentVolName(); | |
e6674585 | 765 | if (cIdSensDr == cIdCurrent[1]) { |
332e9569 | 766 | drRegion = kTRUE; |
767 | } | |
e6674585 | 768 | if (cIdSensAm == cIdCurrent[1]) { |
332e9569 | 769 | amRegion = kTRUE; |
770 | } | |
771 | if (drRegion || amRegion) { | |
fe4da5cc | 772 | |
5c7f4665 | 773 | // The hit coordinates and charge |
774 | gMC->TrackPosition(pos); | |
775 | hits[0] = pos[0]; | |
776 | hits[1] = pos[1]; | |
777 | hits[2] = pos[2]; | |
5c7f4665 | 778 | |
2c8bf4aa | 779 | // The sector number (0 - 17), according to standard coordinate system |
780 | cIdPath = gGeoManager->GetPath(); | |
781 | cIdSector[0] = cIdPath[21]; | |
782 | cIdSector[1] = cIdPath[22]; | |
783 | sec = atoi(cIdSector); | |
82bbf98a | 784 | |
332e9569 | 785 | // The plane and chamber number |
786 | cIdChamber[0] = cIdCurrent[2]; | |
787 | cIdChamber[1] = cIdCurrent[3]; | |
e644678a | 788 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
8a497c18 | 789 | cha = ((Int_t) idChamber / kNplan); |
332e9569 | 790 | pla = ((Int_t) idChamber % kNplan); |
82bbf98a | 791 | |
ce0d6231 | 792 | // The detector number |
793 | det = fGeometry->GetDetector(pla,cha,sec); | |
5c7f4665 | 794 | |
ce0d6231 | 795 | // Special hits only in the drift region |
796 | if ((drRegion) && | |
797 | (gMC->IsTrackEntering())) { | |
5c7f4665 | 798 | |
ce0d6231 | 799 | // Create a track reference at the entrance of each |
800 | // chamber that contains the momentum components of the particle | |
801 | gMC->TrackMomentum(mom); | |
e6add757 | 802 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
793ff80c | 803 | |
ce0d6231 | 804 | // Create the hits from TR photons if electron/positron is |
805 | // entering the drift volume | |
806 | if ((fTR) && | |
807 | (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) { | |
808 | CreateTRhit(det); | |
809 | } | |
f73816f5 | 810 | |
ce0d6231 | 811 | } |
812 | else if ((amRegion) && | |
813 | (gMC->IsTrackExiting())) { | |
f73816f5 | 814 | |
ce0d6231 | 815 | // Create a track reference at the exit of each |
816 | // chamber that contains the momentum components of the particle | |
817 | gMC->TrackMomentum(mom); | |
e6add757 | 818 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
f73816f5 | 819 | |
ce0d6231 | 820 | } |
821 | ||
822 | // Calculate the energy of the delta-electrons | |
823 | eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti; | |
824 | eDelta = TMath::Max(eDelta,0.0); | |
825 | ||
826 | // Generate the electron cluster size | |
827 | if (eDelta > 0.0) { | |
828 | ||
829 | qTot = ((Int_t) (eDelta / kWion) + 1); | |
f73816f5 | 830 | |
030b4415 | 831 | // Create a new dEdx hit |
332e9569 | 832 | if (drRegion) { |
a328fff9 | 833 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 834 | ,det |
835 | ,hits | |
836 | ,qTot | |
25ca55ce | 837 | ,gMC->TrackTime()*1.0e06 |
030b4415 | 838 | ,kTRUE); |
839 | } | |
5c7f4665 | 840 | else { |
a328fff9 | 841 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 842 | ,det |
843 | ,hits | |
844 | ,qTot | |
25ca55ce | 845 | ,gMC->TrackTime()*1.0e06 |
030b4415 | 846 | ,kFALSE); |
847 | } | |
f73816f5 | 848 | |
ce0d6231 | 849 | } |
850 | ||
851 | // Calculate the maximum step size for the next tracking step | |
852 | // Produce only one hit if Ekin is below cutoff | |
853 | aMass = gMC->TrackMass(); | |
854 | if ((gMC->Etot() - aMass) > kEkinMinStep) { | |
855 | ||
856 | // The energy loss according to Bethe Bloch | |
857 | iPdg = TMath::Abs(gMC->TrackPid()); | |
858 | if ((iPdg != kPdgElectron) || | |
859 | ((iPdg == kPdgElectron) && | |
860 | (pTot < kPTotMaxEl))) { | |
861 | gMC->TrackMomentum(mom); | |
862 | pTot = mom.Rho(); | |
863 | betaGamma = pTot / aMass; | |
864 | pp = kPrim * BetheBloch(betaGamma); | |
865 | // Take charge > 1 into account | |
866 | charge = gMC->TrackCharge(); | |
867 | if (TMath::Abs(charge) > 1) { | |
868 | pp = pp * charge*charge; | |
f73816f5 | 869 | } |
ce0d6231 | 870 | } |
871 | else { | |
872 | // Electrons above 20 Mev/c are at the plateau | |
873 | pp = kPrim * kPlateau; | |
874 | } | |
f73816f5 | 875 | |
ce0d6231 | 876 | if (pp > 0.0) { |
877 | do { | |
878 | gMC->GetRandom()->RndmArray(1,random); | |
030b4415 | 879 | } |
ce0d6231 | 880 | while ((random[0] == 1.0) || |
881 | (random[0] == 0.0)); | |
882 | stepSize = - TMath::Log(random[0]) / pp; | |
883 | gMC->SetMaxStep(stepSize); | |
884 | } | |
030b4415 | 885 | |
5c7f4665 | 886 | } |
030b4415 | 887 | |
d3f347ff | 888 | } |
030b4415 | 889 | |
5c7f4665 | 890 | } |
030b4415 | 891 | |
5c7f4665 | 892 | } |
893 | ||
a328fff9 | 894 | //_____________________________________________________________________________ |
895 | void AliTRDv1::StepManagerFixedStep() | |
896 | { | |
897 | // | |
898 | // Slow simulator. Every charged track produces electron cluster as hits | |
899 | // along its path across the drift volume. The step size is fixed in | |
900 | // this version of the step manager. | |
901 | // | |
902 | ||
ce0d6231 | 903 | // PDG code electron |
904 | const Int_t kPdgElectron = 11; | |
905 | ||
a328fff9 | 906 | Int_t pla = 0; |
907 | Int_t cha = 0; | |
908 | Int_t sec = 0; | |
909 | Int_t det = 0; | |
910 | Int_t qTot; | |
911 | ||
912 | Float_t hits[3]; | |
913 | Double_t eDep; | |
914 | ||
915 | Bool_t drRegion = kFALSE; | |
916 | Bool_t amRegion = kFALSE; | |
917 | ||
2c8bf4aa | 918 | TString cIdPath; |
919 | Char_t cIdSector[3]; | |
920 | cIdSector[2] = 0; | |
921 | ||
a328fff9 | 922 | TString cIdCurrent; |
923 | TString cIdSensDr = "J"; | |
924 | TString cIdSensAm = "K"; | |
925 | Char_t cIdChamber[3]; | |
2c8bf4aa | 926 | cIdChamber[2] = 0; |
a328fff9 | 927 | |
030b4415 | 928 | TLorentzVector pos; |
929 | TLorentzVector mom; | |
a328fff9 | 930 | |
931 | const Int_t kNplan = AliTRDgeometry::Nplan(); | |
932 | const Int_t kNcham = AliTRDgeometry::Ncham(); | |
933 | const Int_t kNdetsec = kNplan * kNcham; | |
934 | ||
030b4415 | 935 | const Double_t kBig = 1.0e+12; |
a328fff9 | 936 | |
bc327ce2 | 937 | const Float_t kWion = 23.53; // Ionization energy |
a328fff9 | 938 | const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment |
939 | ||
940 | // Set the maximum step size to a very large number for all | |
941 | // neutral particles and those outside the driftvolume | |
942 | gMC->SetMaxStep(kBig); | |
943 | ||
944 | // If not charged track or already stopped or disappeared, just return. | |
945 | if ((!gMC->TrackCharge()) || | |
ce0d6231 | 946 | gMC->IsTrackDisappeared()) { |
947 | return; | |
948 | } | |
a328fff9 | 949 | |
950 | // Inside a sensitive volume? | |
951 | cIdCurrent = gMC->CurrentVolName(); | |
952 | ||
ce0d6231 | 953 | if (cIdSensDr == cIdCurrent[1]) { |
954 | drRegion = kTRUE; | |
955 | } | |
956 | if (cIdSensAm == cIdCurrent[1]) { | |
957 | amRegion = kTRUE; | |
958 | } | |
a328fff9 | 959 | |
030b4415 | 960 | if ((!drRegion) && |
961 | (!amRegion)) { | |
962 | return; | |
963 | } | |
a328fff9 | 964 | |
965 | // The hit coordinates and charge | |
966 | gMC->TrackPosition(pos); | |
967 | hits[0] = pos[0]; | |
968 | hits[1] = pos[1]; | |
969 | hits[2] = pos[2]; | |
970 | ||
2c8bf4aa | 971 | // The sector number (0 - 17), according to standard coordinate system |
972 | cIdPath = gGeoManager->GetPath(); | |
973 | cIdSector[0] = cIdPath[21]; | |
974 | cIdSector[1] = cIdPath[22]; | |
975 | sec = atoi(cIdSector); | |
a328fff9 | 976 | |
977 | // The plane and chamber number | |
030b4415 | 978 | cIdChamber[0] = cIdCurrent[2]; |
979 | cIdChamber[1] = cIdCurrent[3]; | |
a328fff9 | 980 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
8a497c18 | 981 | cha = ((Int_t) idChamber / kNplan); |
a328fff9 | 982 | pla = ((Int_t) idChamber % kNplan); |
e0d47c25 | 983 | |
030b4415 | 984 | // The detector number |
985 | det = fGeometry->GetDetector(pla,cha,sec); | |
986 | ||
25ca55ce | 987 | // 0: InFlight 1:Entering 2:Exiting |
030b4415 | 988 | Int_t trkStat = 0; |
a328fff9 | 989 | |
990 | // Special hits only in the drift region | |
ce0d6231 | 991 | if ((drRegion) && |
992 | (gMC->IsTrackEntering())) { | |
a328fff9 | 993 | |
ce0d6231 | 994 | // Create a track reference at the entrance of each |
995 | // chamber that contains the momentum components of the particle | |
996 | gMC->TrackMomentum(mom); | |
e6add757 | 997 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
ce0d6231 | 998 | trkStat = 1; |
a328fff9 | 999 | |
ce0d6231 | 1000 | // Create the hits from TR photons if electron/positron is |
1001 | // entering the drift volume | |
1002 | if ((fTR) && | |
1003 | (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) { | |
030b4415 | 1004 | CreateTRhit(det); |
1005 | } | |
a328fff9 | 1006 | |
ce0d6231 | 1007 | } |
1008 | else if ((amRegion) && | |
1009 | (gMC->IsTrackExiting())) { | |
1010 | ||
1011 | // Create a track reference at the exit of each | |
1012 | // chamber that contains the momentum components of the particle | |
1013 | gMC->TrackMomentum(mom); | |
e6add757 | 1014 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
ce0d6231 | 1015 | trkStat = 2; |
1016 | ||
a328fff9 | 1017 | } |
1018 | ||
1019 | // Calculate the charge according to GEANT Edep | |
1020 | // Create a new dEdx hit | |
1021 | eDep = TMath::Max(gMC->Edep(),0.0) * 1.0e+09; | |
1022 | qTot = (Int_t) (eDep / kWion); | |
ce0d6231 | 1023 | if ((qTot) || |
1024 | (trkStat)) { | |
1025 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() | |
1026 | ,det | |
1027 | ,hits | |
1028 | ,qTot | |
25ca55ce | 1029 | ,gMC->TrackTime()*1.0e06 |
ce0d6231 | 1030 | ,drRegion); |
1031 | } | |
a328fff9 | 1032 | |
1033 | // Set Maximum Step Size | |
1034 | // Produce only one hit if Ekin is below cutoff | |
030b4415 | 1035 | if ((gMC->Etot() - gMC->TrackMass()) < kEkinMinStep) { |
1036 | return; | |
1037 | } | |
a328fff9 | 1038 | gMC->SetMaxStep(fStepSize); |
1039 | ||
1040 | } | |
1041 | ||
5c7f4665 | 1042 | //_____________________________________________________________________________ |
1043 | Double_t AliTRDv1::BetheBloch(Double_t bg) | |
1044 | { | |
1045 | // | |
1046 | // Parametrization of the Bethe-Bloch-curve | |
1047 | // The parametrization is the same as for the TPC and is taken from Lehrhaus. | |
1048 | // | |
1049 | ||
1050 | // This parameters have been adjusted to averaged values from GEANT | |
f57bb418 | 1051 | const Double_t kP1 = 7.17960e-02; |
1052 | const Double_t kP2 = 8.54196; | |
1053 | const Double_t kP3 = 1.38065e-06; | |
1054 | const Double_t kP4 = 5.30972; | |
1055 | const Double_t kP5 = 2.83798; | |
5c7f4665 | 1056 | |
f73816f5 | 1057 | // Lower cutoff of the Bethe-Bloch-curve to limit step sizes |
1058 | const Double_t kBgMin = 0.8; | |
1059 | const Double_t kBBMax = 6.83298; | |
f73816f5 | 1060 | |
1061 | if (bg > kBgMin) { | |
030b4415 | 1062 | Double_t yy = bg / TMath::Sqrt(1.0 + bg*bg); |
5c7f4665 | 1063 | Double_t aa = TMath::Power(yy,kP4); |
030b4415 | 1064 | Double_t bb = TMath::Power((1.0/bg),kP5); |
5c7f4665 | 1065 | bb = TMath::Log(kP3 + bb); |
030b4415 | 1066 | return ((kP2 - aa - bb) * kP1 / aa); |
5c7f4665 | 1067 | } |
f73816f5 | 1068 | else { |
1069 | return kBBMax; | |
1070 | } | |
d3f347ff | 1071 | |
fe4da5cc | 1072 | } |
5c7f4665 | 1073 | |
a328fff9 | 1074 | //_____________________________________________________________________________ |
c4214bc0 | 1075 | Double_t AliTRDv1::BetheBlochGeant(Double_t bg) |
a328fff9 | 1076 | { |
1077 | // | |
1078 | // Return dN/dx (number of primary collisions per centimeter) | |
1079 | // for given beta*gamma factor. | |
1080 | // | |
1081 | // Implemented by K.Oyama according to GEANT 3 parametrization shown in | |
1082 | // A.Andronic's webpage: http://www-alice.gsi.de/trd/papers/dedx/dedx.html | |
1083 | // This must be used as a set with IntSpecGeant. | |
1084 | // | |
1085 | ||
030b4415 | 1086 | Int_t i = 0; |
a328fff9 | 1087 | |
030b4415 | 1088 | Double_t arrG[20] = { 1.100000, 1.200000, 1.300000, 1.500000 |
1089 | , 1.800000, 2.000000, 2.500000, 3.000000 | |
1090 | , 4.000000, 7.000000, 10.000000, 20.000000 | |
1091 | , 40.000000, 70.000000, 100.000000, 300.000000 | |
1092 | , 600.000000, 1000.000000, 3000.000000, 10000.000000 }; | |
a328fff9 | 1093 | |
030b4415 | 1094 | Double_t arrNC[20] = { 75.009056, 45.508083, 35.299252, 27.116327 |
1095 | , 22.734999, 21.411915, 19.934095, 19.449375 | |
1096 | , 19.344431, 20.185553, 21.027925, 22.912676 | |
1097 | , 24.933352, 26.504053, 27.387468, 29.566597 | |
1098 | , 30.353779, 30.787134, 31.129285, 31.157350 }; | |
1099 | ||
1100 | // Betagamma to gamma | |
1101 | Double_t g = TMath::Sqrt(1.0 + bg*bg); | |
a328fff9 | 1102 | |
1103 | // Find the index just before the point we need. | |
030b4415 | 1104 | for (i = 0; i < 18; i++) { |
1105 | if ((arrG[i] < g) && | |
1106 | (arrG[i+1] > g)) { | |
a328fff9 | 1107 | break; |
030b4415 | 1108 | } |
1109 | } | |
a328fff9 | 1110 | |
1111 | // Simple interpolation. | |
030b4415 | 1112 | Double_t pp = ((arrNC[i+1] - arrNC[i]) / (arrG[i+1] - arrG[i])) |
1113 | * (g - arrG[i]) + arrNC[i]; | |
a328fff9 | 1114 | |
030b4415 | 1115 | return pp; |
a328fff9 | 1116 | |
1117 | } | |
1118 | ||
5c7f4665 | 1119 | //_____________________________________________________________________________ |
1120 | Double_t Ermilova(Double_t *x, Double_t *) | |
1121 | { | |
1122 | // | |
1123 | // Calculates the delta-ray energy distribution according to Ermilova. | |
1124 | // Logarithmic scale ! | |
1125 | // | |
1126 | ||
1127 | Double_t energy; | |
1128 | Double_t dpos; | |
1129 | Double_t dnde; | |
1130 | ||
030b4415 | 1131 | Int_t pos1; |
1132 | Int_t pos2; | |
5c7f4665 | 1133 | |
8230f242 | 1134 | const Int_t kNv = 31; |
5c7f4665 | 1135 | |
030b4415 | 1136 | Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120 |
1137 | , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052 | |
1138 | , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915 | |
1139 | , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009 | |
1140 | , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103 | |
1141 | , 9.4727, 9.9035, 10.3735, 10.5966, 10.8198 | |
1142 | , 11.5129 }; | |
1143 | ||
1144 | Float_t vye[kNv] = { 80.0, 31.0, 23.3, 21.1, 21.0 | |
1145 | , 20.9, 20.8, 20.0, 16.0, 11.0 | |
1146 | , 8.0, 6.0, 5.2, 4.6, 4.0 | |
1147 | , 3.5, 3.0, 1.4, 0.67, 0.44 | |
1148 | , 0.3, 0.18, 0.12, 0.08, 0.056 | |
1149 | , 0.04, 0.023, 0.015, 0.011, 0.01 | |
1150 | , 0.004 }; | |
5c7f4665 | 1151 | |
1152 | energy = x[0]; | |
1153 | ||
1154 | // Find the position | |
030b4415 | 1155 | pos1 = 0; |
1156 | pos2 = 0; | |
5c7f4665 | 1157 | dpos = 0; |
1158 | do { | |
1159 | dpos = energy - vxe[pos2++]; | |
1160 | } | |
1161 | while (dpos > 0); | |
1162 | pos2--; | |
030b4415 | 1163 | if (pos2 > kNv) { |
1164 | pos2 = kNv - 1; | |
1165 | } | |
5c7f4665 | 1166 | pos1 = pos2 - 1; |
1167 | ||
1168 | // Differentiate between the sampling points | |
1169 | dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]); | |
1170 | ||
1171 | return dnde; | |
1172 | ||
1173 | } | |
a328fff9 | 1174 | |
1175 | //_____________________________________________________________________________ | |
1176 | Double_t IntSpecGeant(Double_t *x, Double_t *) | |
1177 | { | |
1178 | // | |
1179 | // Integrated spectrum from Geant3 | |
1180 | // | |
1181 | ||
96efaf83 | 1182 | const Int_t npts = 83; |
030b4415 | 1183 | Double_t arre[npts] = { 2.421257, 2.483278, 2.534301, 2.592230 |
1184 | , 2.672067, 2.813299, 3.015059, 3.216819 | |
1185 | , 3.418579, 3.620338, 3.868209, 3.920198 | |
1186 | , 3.978284, 4.063923, 4.186264, 4.308605 | |
1187 | , 4.430946, 4.553288, 4.724261, 4.837736 | |
1188 | , 4.999842, 5.161949, 5.324056, 5.486163 | |
1189 | , 5.679688, 5.752998, 5.857728, 5.962457 | |
1190 | , 6.067185, 6.171914, 6.315653, 6.393674 | |
1191 | , 6.471694, 6.539689, 6.597658, 6.655627 | |
1192 | , 6.710957, 6.763648, 6.816338, 6.876198 | |
1193 | , 6.943227, 7.010257, 7.106285, 7.252151 | |
1194 | , 7.460531, 7.668911, 7.877290, 8.085670 | |
1195 | , 8.302979, 8.353585, 8.413120, 8.483500 | |
1196 | , 8.541030, 8.592857, 8.668865, 8.820485 | |
1197 | , 9.037086, 9.253686, 9.470286, 9.686887 | |
1198 | , 9.930838, 9.994655, 10.085822, 10.176990 | |
1199 | , 10.268158, 10.359325, 10.503614, 10.627565 | |
1200 | , 10.804637, 10.981709, 11.158781, 11.335854 | |
1201 | , 11.593397, 11.781165, 12.049404, 12.317644 | |
1202 | , 12.585884, 12.854123, 14.278421, 16.975889 | |
1203 | , 20.829416, 24.682943, 28.536469 }; | |
1204 | ||
1205 | Double_t arrdnde[npts] = { 10.960000, 10.960000, 10.359500, 9.811340 | |
1206 | , 9.1601500, 8.206670, 6.919630, 5.655430 | |
1207 | , 4.6221300, 3.777610, 3.019560, 2.591950 | |
1208 | , 2.5414600, 2.712920, 3.327460, 4.928240 | |
1209 | , 7.6185300, 10.966700, 12.225800, 8.094750 | |
1210 | , 3.3586900, 1.553650, 1.209600, 1.263840 | |
1211 | , 1.3241100, 1.312140, 1.255130, 1.165770 | |
1212 | , 1.0594500, 0.945450, 0.813231, 0.699837 | |
1213 | , 0.6235580, 2.260990, 2.968350, 2.240320 | |
1214 | , 1.7988300, 1.553300, 1.432070, 1.535520 | |
1215 | , 1.4429900, 1.247990, 1.050750, 0.829549 | |
1216 | , 0.5900280, 0.395897, 0.268741, 0.185320 | |
1217 | , 0.1292120, 0.103545, 0.0949525, 0.101535 | |
1218 | , 0.1276380, 0.134216, 0.123816, 0.104557 | |
1219 | , 0.0751843, 0.0521745, 0.0373546, 0.0275391 | |
1220 | , 0.0204713, 0.0169234, 0.0154552, 0.0139194 | |
1221 | , 0.0125592, 0.0113638, 0.0107354, 0.0102137 | |
1222 | , 0.00845984, 0.00683338, 0.00556836, 0.00456874 | |
1223 | , 0.0036227, 0.00285991, 0.00226664, 0.00172234 | |
1224 | , 0.00131226, 0.00100284, 0.000465492, 7.26607e-05 | |
1225 | , 3.63304e-06, 0.0000000, 0.0000000 }; | |
1226 | ||
1227 | Int_t i; | |
a328fff9 | 1228 | Double_t energy = x[0]; |
a328fff9 | 1229 | |
225211c8 | 1230 | if (energy >= arre[npts-1]) { |
1231 | return 0.0; | |
1232 | } | |
1233 | ||
030b4415 | 1234 | for (i = 0; i < npts; i++) { |
1235 | if (energy < arre[i]) { | |
1236 | break; | |
1237 | } | |
1238 | } | |
a328fff9 | 1239 | |
030b4415 | 1240 | if (i == 0) { |
1241 | AliErrorGeneral("AliTRDv1::IntSpecGeant","Given energy value is too small or zero"); | |
1242 | } | |
a328fff9 | 1243 | |
f57bb418 | 1244 | return arrdnde[i]; |
a328fff9 | 1245 | |
1246 | } |