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