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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 | ||
122 | TString vpStr = "ALIC_1/B077_1/BSEGMO"; | |
123 | TString vpApp1 = "_1/BTRD"; | |
124 | TString vpApp2 = "_1"; | |
125 | TString vpApp3 = "/UTR1_1/UTS1_1/UTI1_1/UT"; | |
126 | ||
127 | TString snStr = "TRD/sm"; | |
128 | TString snApp1 = "/st"; | |
129 | TString snApp2 = "/pl"; | |
130 | ||
131 | // | |
132 | // The super modules | |
133 | // The symbolic names are: TRD/sm00 | |
134 | // ... | |
135 | // TRD/sm17 | |
136 | // | |
137 | for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) { | |
138 | ||
139 | volPath = vpStr; | |
140 | volPath += isect; | |
141 | volPath += vpApp1; | |
142 | volPath += isect; | |
143 | volPath += vpApp2; | |
144 | ||
145 | symName = snStr; | |
146 | symName += Form("%02d",isect); | |
147 | ||
148 | gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data()); | |
149 | ||
150 | } | |
151 | ||
152 | // | |
153 | // The readout chambers | |
154 | // The symbolic names are: TRD/sm00/st0/pl0 | |
155 | // ... | |
156 | // TRD/sm17/st4/pl5 | |
157 | // | |
158 | for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) { | |
8bf0cd64 | 159 | |
160 | if (fGeometry->GetSMstatus(isect) == 0) continue; | |
161 | ||
f57bb418 | 162 | for (Int_t icham = 0; icham < AliTRDgeometry::Ncham(); icham++) { |
163 | for (Int_t iplan = 0; iplan < AliTRDgeometry::Nplan(); iplan++) { | |
164 | ||
165 | Int_t idet = AliTRDgeometry::GetDetectorSec(iplan,icham); | |
166 | ||
167 | volPath = vpStr; | |
168 | volPath += isect; | |
169 | volPath += vpApp1; | |
170 | volPath += isect; | |
171 | volPath += vpApp2; | |
172 | volPath += vpApp3; | |
173 | volPath += Form("%02d",idet); | |
174 | volPath += vpApp2; | |
175 | ||
176 | symName = snStr; | |
177 | symName += Form("%02d",isect); | |
178 | symName += snApp1; | |
179 | symName += icham; | |
180 | symName += snApp2; | |
181 | symName += iplan; | |
182 | ||
51a5f1d0 | 183 | TGeoPNEntry *alignableEntry = |
184 | gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data()); | |
f57bb418 | 185 | |
170c35f1 | 186 | // Add the tracking to local matrix following the TPC example |
51a5f1d0 | 187 | if (alignableEntry) { |
188 | const char *path = alignableEntry->GetTitle(); | |
189 | if (!gGeoManager->cd(path)) { | |
190 | AliFatal(Form("Volume path %s not valid!",path)); | |
191 | } | |
192 | TGeoHMatrix *globMatrix = gGeoManager->GetCurrentMatrix(); | |
193 | Double_t sectorAngle = 20.0 * (isect % 18) + 10.0; | |
194 | TGeoHMatrix *t2lMatrix = new TGeoHMatrix(); | |
195 | t2lMatrix->RotateZ(sectorAngle); | |
196 | t2lMatrix->MultiplyLeft(&(globMatrix->Inverse())); | |
197 | alignableEntry->SetMatrix(t2lMatrix); | |
198 | } | |
199 | else { | |
200 | AliError(Form("Alignable entry %s is not valid!",symName.Data())); | |
201 | } | |
8bf0cd64 | 202 | |
f57bb418 | 203 | } |
204 | } | |
205 | } | |
206 | ||
207 | } | |
208 | ||
fe4da5cc | 209 | //_____________________________________________________________________________ |
210 | void AliTRDv1::CreateGeometry() | |
211 | { | |
212 | // | |
851d3db9 | 213 | // Create the GEANT geometry for the Transition Radiation Detector - Version 1 |
5c7f4665 | 214 | // This version covers the full azimuth. |
d3f347ff | 215 | // |
216 | ||
82bbf98a | 217 | // Check that FRAME is there otherwise we have no place where to put the TRD |
8230f242 | 218 | AliModule* frame = gAlice->GetModule("FRAME"); |
030b4415 | 219 | if (!frame) { |
220 | AliError("TRD needs FRAME to be present\n"); | |
221 | return; | |
222 | } | |
d3f347ff | 223 | |
82bbf98a | 224 | // Define the chambers |
225 | AliTRD::CreateGeometry(); | |
d3f347ff | 226 | |
fe4da5cc | 227 | } |
228 | ||
229 | //_____________________________________________________________________________ | |
230 | void AliTRDv1::CreateMaterials() | |
231 | { | |
232 | // | |
851d3db9 | 233 | // Create materials for the Transition Radiation Detector version 1 |
fe4da5cc | 234 | // |
82bbf98a | 235 | |
d3f347ff | 236 | AliTRD::CreateMaterials(); |
82bbf98a | 237 | |
fe4da5cc | 238 | } |
239 | ||
793ff80c | 240 | //_____________________________________________________________________________ |
241 | void AliTRDv1::CreateTRhit(Int_t det) | |
242 | { | |
243 | // | |
244 | // Creates an electron cluster from a TR photon. | |
245 | // The photon is assumed to be created a the end of the radiator. The | |
246 | // distance after which it deposits its energy takes into account the | |
247 | // absorbtion of the entrance window and of the gas mixture in drift | |
248 | // volume. | |
249 | // | |
250 | ||
793ff80c | 251 | // Ionization energy |
bc327ce2 | 252 | const Float_t kWion = 23.53; |
793ff80c | 253 | |
254 | // Maximum number of TR photons per track | |
255 | const Int_t kNTR = 50; | |
256 | ||
030b4415 | 257 | TLorentzVector mom; |
258 | TLorentzVector pos; | |
793ff80c | 259 | |
ce0d6231 | 260 | Float_t eTR[kNTR]; |
261 | Int_t nTR; | |
793ff80c | 262 | |
ce0d6231 | 263 | // Create TR photons |
264 | gMC->TrackMomentum(mom); | |
265 | Float_t pTot = mom.Rho(); | |
266 | fTR->CreatePhotons(11,pTot,nTR,eTR); | |
267 | if (nTR > kNTR) { | |
268 | AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR)); | |
269 | } | |
f73816f5 | 270 | |
ce0d6231 | 271 | // Loop through the TR photons |
272 | for (Int_t iTR = 0; iTR < nTR; iTR++) { | |
793ff80c | 273 | |
ce0d6231 | 274 | Float_t energyMeV = eTR[iTR] * 0.001; |
275 | Float_t energyeV = eTR[iTR] * 1000.0; | |
276 | Float_t absLength = 0.0; | |
277 | Float_t sigma = 0.0; | |
793ff80c | 278 | |
ce0d6231 | 279 | // Take the absorbtion in the entrance window into account |
280 | Double_t muMy = fTR->GetMuMy(energyMeV); | |
281 | sigma = muMy * fFoilDensity; | |
282 | if (sigma > 0.0) { | |
283 | absLength = gRandom->Exp(1.0/sigma); | |
284 | if (absLength < AliTRDgeometry::MyThick()) { | |
842287f2 | 285 | continue; |
286 | } | |
ce0d6231 | 287 | } |
288 | else { | |
289 | continue; | |
290 | } | |
793ff80c | 291 | |
ce0d6231 | 292 | // The absorbtion cross sections in the drift gas |
293 | // Gas-mixture (Xe/CO2) | |
294 | Double_t muXe = fTR->GetMuXe(energyMeV); | |
295 | Double_t muCO = fTR->GetMuCO(energyMeV); | |
296 | sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity * fTR->GetTemp(); | |
297 | ||
298 | // The distance after which the energy of the TR photon | |
299 | // is deposited. | |
300 | if (sigma > 0.0) { | |
301 | absLength = gRandom->Exp(1.0/sigma); | |
302 | if (absLength > (AliTRDgeometry::DrThick() | |
303 | + AliTRDgeometry::AmThick())) { | |
842287f2 | 304 | continue; |
305 | } | |
ce0d6231 | 306 | } |
307 | else { | |
308 | continue; | |
309 | } | |
793ff80c | 310 | |
ce0d6231 | 311 | // The position of the absorbtion |
312 | Float_t posHit[3]; | |
313 | gMC->TrackPosition(pos); | |
314 | posHit[0] = pos[0] + mom[0] / pTot * absLength; | |
315 | posHit[1] = pos[1] + mom[1] / pTot * absLength; | |
316 | posHit[2] = pos[2] + mom[2] / pTot * absLength; | |
793ff80c | 317 | |
ce0d6231 | 318 | // Create the charge |
319 | Int_t q = ((Int_t) (energyeV / kWion)); | |
793ff80c | 320 | |
ce0d6231 | 321 | // Add the hit to the array. TR photon hits are marked |
322 | // by negative charge | |
323 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() | |
324 | ,det | |
325 | ,posHit | |
326 | ,-q | |
25ca55ce | 327 | ,gMC->TrackTime()*1.0e06 |
d4c6453d | 328 | ,kTRUE); |
793ff80c | 329 | |
330 | } | |
331 | ||
332 | } | |
333 | ||
5c7f4665 | 334 | //_____________________________________________________________________________ |
335 | void AliTRDv1::Init() | |
336 | { | |
337 | // | |
338 | // Initialise Transition Radiation Detector after geometry has been built. | |
5c7f4665 | 339 | // |
340 | ||
341 | AliTRD::Init(); | |
342 | ||
45160b1f | 343 | AliDebug(1,"Slow simulator\n"); |
bd0f8685 | 344 | |
345 | // Switch on TR simulation as default | |
346 | if (!fTRon) { | |
45160b1f | 347 | AliInfo("TR simulation off"); |
bd0f8685 | 348 | } |
349 | else { | |
cb2f9e9b | 350 | fTR = new AliTRDsimTR(); |
bd0f8685 | 351 | } |
5c7f4665 | 352 | |
353 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) | |
354 | const Float_t kPoti = 12.1; | |
355 | // Maximum energy (50 keV); | |
356 | const Float_t kEend = 50000.0; | |
357 | // Ermilova distribution for the delta-ray spectrum | |
030b4415 | 358 | Float_t poti = TMath::Log(kPoti); |
359 | Float_t eEnd = TMath::Log(kEend); | |
a328fff9 | 360 | |
361 | // Ermilova distribution for the delta-ray spectrum | |
c4214bc0 | 362 | fDeltaE = new TF1("deltae" ,Ermilova ,poti,eEnd,0); |
a328fff9 | 363 | |
364 | // Geant3 distribution for the delta-ray spectrum | |
c4214bc0 | 365 | fDeltaG = new TF1("deltag",IntSpecGeant,2.421257,28.536469,0); |
5c7f4665 | 366 | |
45160b1f | 367 | AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++"); |
5c7f4665 | 368 | |
fe4da5cc | 369 | } |
370 | ||
5c7f4665 | 371 | //_____________________________________________________________________________ |
372 | void AliTRDv1::StepManager() | |
a328fff9 | 373 | { |
374 | // | |
c4214bc0 | 375 | // Slow simulator. Every charged track produces electron cluster as hits |
a328fff9 | 376 | // along its path across the drift volume. |
377 | // | |
378 | ||
379 | switch (fTypeOfStepManager) { | |
a6dd11e9 | 380 | case 0: |
381 | StepManagerErmilova(); | |
382 | break; | |
383 | case 1: | |
384 | StepManagerGeant(); | |
385 | break; | |
386 | case 2: | |
387 | StepManagerFixedStep(); | |
388 | break; | |
389 | default: | |
390 | AliWarning("Not a valid Step Manager."); | |
a328fff9 | 391 | } |
392 | ||
393 | } | |
394 | ||
395 | //_____________________________________________________________________________ | |
396 | void AliTRDv1::SelectStepManager(Int_t t) | |
397 | { | |
398 | // | |
399 | // Selects a step manager type: | |
400 | // 0 - Ermilova | |
401 | // 1 - Geant3 | |
402 | // 2 - Fixed step size | |
403 | // | |
404 | ||
a328fff9 | 405 | fTypeOfStepManager = t; |
45160b1f | 406 | AliInfo(Form("Step Manager type %d was selected",fTypeOfStepManager)); |
a328fff9 | 407 | |
408 | } | |
409 | ||
410 | //_____________________________________________________________________________ | |
411 | void AliTRDv1::StepManagerGeant() | |
412 | { | |
413 | // | |
c4214bc0 | 414 | // Slow simulator. Every charged track produces electron cluster as hits |
a328fff9 | 415 | // along its path across the drift volume. The step size is set acording |
416 | // to Bethe-Bloch. The energy distribution of the delta electrons follows | |
417 | // a spectrum taken from Geant3. | |
418 | // | |
f2e3a0b5 | 419 | // Version by A. Bercuci |
420 | // | |
421 | ||
c4214bc0 | 422 | Int_t pla = 0; |
423 | Int_t cha = 0; | |
424 | Int_t sec = 0; | |
425 | Int_t det = 0; | |
426 | Int_t iPdg; | |
427 | Int_t qTot; | |
428 | ||
429 | Float_t hits[3]; | |
430 | Float_t charge; | |
431 | Float_t aMass; | |
432 | ||
030b4415 | 433 | Double_t pTot = 0; |
c4214bc0 | 434 | Double_t eDelta; |
030b4415 | 435 | Double_t betaGamma; |
436 | Double_t pp; | |
f2e3a0b5 | 437 | Double_t stepSize = 0; |
c4214bc0 | 438 | |
439 | Bool_t drRegion = kFALSE; | |
440 | Bool_t amRegion = kFALSE; | |
441 | ||
2c8bf4aa | 442 | TString cIdPath; |
443 | Char_t cIdSector[3]; | |
444 | cIdSector[2] = 0; | |
445 | ||
c4214bc0 | 446 | TString cIdCurrent; |
447 | TString cIdSensDr = "J"; | |
448 | TString cIdSensAm = "K"; | |
449 | Char_t cIdChamber[3]; | |
450 | cIdChamber[2] = 0; | |
451 | ||
030b4415 | 452 | TLorentzVector pos; |
453 | TLorentzVector mom; | |
c4214bc0 | 454 | |
030b4415 | 455 | TArrayI processes; |
f2e3a0b5 | 456 | |
c4214bc0 | 457 | const Int_t kNplan = AliTRDgeometry::Nplan(); |
458 | const Int_t kNcham = AliTRDgeometry::Ncham(); | |
459 | const Int_t kNdetsec = kNplan * kNcham; | |
460 | ||
030b4415 | 461 | const Double_t kBig = 1.0e+12; // Infinitely big |
bc327ce2 | 462 | const Float_t kWion = 23.53; // Ionization energy |
c4214bc0 | 463 | const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g |
464 | ||
465 | // Minimum energy for the step size adjustment | |
466 | const Float_t kEkinMinStep = 1.0e-5; | |
467 | // energy threshold for production of delta electrons | |
f2e3a0b5 | 468 | const Float_t kECut = 1.0e4; |
469 | // Parameters entering the parametrized range for delta electrons | |
030b4415 | 470 | const Float_t kRa = 5.37e-4; |
f2e3a0b5 | 471 | const Float_t kRb = 0.9815; |
030b4415 | 472 | const Float_t kRc = 3.123e-3; |
f2e3a0b5 | 473 | // Gas density -> To be made user adjustable ! |
030b4415 | 474 | // [0.85*0.00549+0.15*0.00186 (Xe-CO2 85-15)] |
475 | const Float_t kRho = 0.004945 ; | |
a328fff9 | 476 | |
c4214bc0 | 477 | // Plateau value of the energy-loss for electron in xenon |
030b4415 | 478 | // The averaged value (26/3/99) |
c4214bc0 | 479 | const Float_t kPlateau = 1.55; |
030b4415 | 480 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) |
481 | const Float_t kPrim = 19.34; | |
c4214bc0 | 482 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) |
483 | const Float_t kPoti = 12.1; | |
030b4415 | 484 | // PDG code electron |
485 | const Int_t kPdgElectron = 11; | |
c4214bc0 | 486 | |
487 | // Set the maximum step size to a very large number for all | |
488 | // neutral particles and those outside the driftvolume | |
489 | gMC->SetMaxStep(kBig); | |
490 | ||
491 | // Use only charged tracks | |
492 | if (( gMC->TrackCharge() ) && | |
c4214bc0 | 493 | (!gMC->IsTrackDisappeared())) { |
494 | ||
495 | // Inside a sensitive volume? | |
496 | drRegion = kFALSE; | |
497 | amRegion = kFALSE; | |
498 | cIdCurrent = gMC->CurrentVolName(); | |
499 | if (cIdSensDr == cIdCurrent[1]) { | |
500 | drRegion = kTRUE; | |
501 | } | |
502 | if (cIdSensAm == cIdCurrent[1]) { | |
503 | amRegion = kTRUE; | |
504 | } | |
505 | if (drRegion || amRegion) { | |
a328fff9 | 506 | |
c4214bc0 | 507 | // The hit coordinates and charge |
508 | gMC->TrackPosition(pos); | |
509 | hits[0] = pos[0]; | |
510 | hits[1] = pos[1]; | |
511 | hits[2] = pos[2]; | |
512 | ||
2c8bf4aa | 513 | // The sector number (0 - 17), according to standard coordinate system |
514 | cIdPath = gGeoManager->GetPath(); | |
515 | cIdSector[0] = cIdPath[21]; | |
516 | cIdSector[1] = cIdPath[22]; | |
517 | sec = atoi(cIdSector); | |
c4214bc0 | 518 | |
519 | // The plane and chamber number | |
030b4415 | 520 | cIdChamber[0] = cIdCurrent[2]; |
521 | cIdChamber[1] = cIdCurrent[3]; | |
c4214bc0 | 522 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
8a497c18 | 523 | cha = ((Int_t) idChamber / kNplan); |
c4214bc0 | 524 | pla = ((Int_t) idChamber % kNplan); |
525 | ||
ce0d6231 | 526 | // The detector number |
527 | det = fGeometry->GetDetector(pla,cha,sec); | |
c4214bc0 | 528 | |
ce0d6231 | 529 | // Special hits only in the drift region |
530 | if ((drRegion) && | |
531 | (gMC->IsTrackEntering())) { | |
c4214bc0 | 532 | |
ce0d6231 | 533 | // Create a track reference at the entrance of each |
534 | // chamber that contains the momentum components of the particle | |
535 | gMC->TrackMomentum(mom); | |
e6add757 | 536 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
c4214bc0 | 537 | |
ce0d6231 | 538 | // Create the hits from TR photons if electron/positron is |
539 | // entering the drift volume | |
540 | if ((fTR) && | |
541 | (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) { | |
542 | CreateTRhit(det); | |
543 | } | |
f2e3a0b5 | 544 | |
ce0d6231 | 545 | } |
546 | else if ((amRegion) && | |
547 | (gMC->IsTrackExiting())) { | |
f2e3a0b5 | 548 | |
ce0d6231 | 549 | // Create a track reference at the exit of each |
550 | // chamber that contains the momentum components of the particle | |
551 | gMC->TrackMomentum(mom); | |
e6add757 | 552 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
c4214bc0 | 553 | |
ce0d6231 | 554 | } |
c4214bc0 | 555 | |
ce0d6231 | 556 | // Calculate the energy of the delta-electrons |
557 | // modified by Alex Bercuci (A.Bercuci@gsi.de) on 26.01.06 | |
558 | // take into account correlation with the underlying GEANT tracking | |
559 | // mechanism. see | |
560 | // http://www-linux.gsi.de/~abercuci/Contributions/TRD/index.html | |
561 | // | |
562 | // determine the most significant process (last on the processes list) | |
563 | // which caused this hit | |
564 | gMC->StepProcesses(processes); | |
565 | Int_t nofprocesses = processes.GetSize(); | |
566 | Int_t pid; | |
567 | if (!nofprocesses) { | |
568 | pid = 0; | |
569 | } | |
570 | else { | |
571 | pid = processes[nofprocesses-1]; | |
572 | } | |
f2e3a0b5 | 573 | |
ce0d6231 | 574 | // Generate Edep according to GEANT parametrisation |
575 | eDelta = TMath::Exp(fDeltaG->GetRandom()) - kPoti; | |
576 | eDelta = TMath::Max(eDelta,0.0); | |
577 | Float_t prRange = 0.0; | |
578 | Float_t range = gMC->TrackLength() - fTrackLength0; | |
579 | // merge GEANT tracker information with locally cooked one | |
580 | if (gAlice->GetMCApp()->GetCurrentTrackNumber() == fPrimaryTrackPid) { | |
581 | if (pid == 27) { | |
582 | if (eDelta >= kECut) { | |
583 | prRange = kRa * eDelta * 0.001 | |
584 | * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho; | |
585 | if (prRange >= (3.7 - range)) { | |
586 | eDelta *= 0.1; | |
587 | } | |
588 | } | |
589 | } | |
590 | else if (pid == 1) { | |
591 | if (eDelta < kECut) { | |
592 | eDelta *= 0.5; | |
593 | } | |
594 | else { | |
595 | prRange = kRa * eDelta * 0.001 | |
596 | * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho; | |
597 | if (prRange >= ((AliTRDgeometry::DrThick() | |
598 | + AliTRDgeometry::AmThick()) - range)) { | |
599 | eDelta *= 0.05; | |
600 | } | |
601 | else { | |
f2e3a0b5 | 602 | eDelta *= 0.5; |
ce0d6231 | 603 | } |
604 | } | |
605 | } | |
f2e3a0b5 | 606 | else { |
607 | eDelta = 0.0; | |
ce0d6231 | 608 | } |
609 | } | |
610 | else { | |
611 | eDelta = 0.0; | |
612 | } | |
c4214bc0 | 613 | |
ce0d6231 | 614 | // Generate the electron cluster size |
615 | if (eDelta > 0.0) { | |
f2e3a0b5 | 616 | |
ce0d6231 | 617 | qTot = ((Int_t) (eDelta / kWion) + 1); |
618 | ||
619 | // Create a new dEdx hit | |
030b4415 | 620 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
621 | ,det | |
622 | ,hits | |
623 | ,qTot | |
25ca55ce | 624 | ,gMC->TrackTime()*1.0e06 |
030b4415 | 625 | ,drRegion); |
c4214bc0 | 626 | |
ce0d6231 | 627 | } |
628 | ||
629 | // Calculate the maximum step size for the next tracking step | |
630 | // Produce only one hit if Ekin is below cutoff | |
631 | aMass = gMC->TrackMass(); | |
632 | if ((gMC->Etot() - aMass) > kEkinMinStep) { | |
633 | ||
634 | // The energy loss according to Bethe Bloch | |
635 | iPdg = TMath::Abs(gMC->TrackPid()); | |
636 | if ((iPdg != kPdgElectron) || | |
637 | ((iPdg == kPdgElectron) && | |
638 | (pTot < kPTotMaxEl))) { | |
639 | gMC->TrackMomentum(mom); | |
640 | pTot = mom.Rho(); | |
641 | betaGamma = pTot / aMass; | |
642 | pp = BetheBlochGeant(betaGamma); | |
643 | // Take charge > 1 into account | |
644 | charge = gMC->TrackCharge(); | |
645 | if (TMath::Abs(charge) > 1) { | |
646 | pp = pp * charge*charge; | |
647 | } | |
648 | } | |
649 | else { | |
650 | // Electrons above 20 Mev/c are at the plateau | |
651 | pp = kPrim * kPlateau; | |
652 | } | |
f2e3a0b5 | 653 | |
ce0d6231 | 654 | Int_t nsteps = 0; |
655 | do { | |
656 | nsteps = gRandom->Poisson(pp); | |
657 | } while(!nsteps); | |
658 | stepSize = 1.0 / nsteps; | |
659 | gMC->SetMaxStep(stepSize); | |
f2e3a0b5 | 660 | |
c4214bc0 | 661 | } |
f2e3a0b5 | 662 | |
c4214bc0 | 663 | } |
f2e3a0b5 | 664 | |
c4214bc0 | 665 | } |
f2e3a0b5 | 666 | |
a328fff9 | 667 | } |
668 | ||
669 | //_____________________________________________________________________________ | |
670 | void AliTRDv1::StepManagerErmilova() | |
5c7f4665 | 671 | { |
672 | // | |
5c7f4665 | 673 | // Slow simulator. Every charged track produces electron cluster as hits |
674 | // along its path across the drift volume. The step size is set acording | |
675 | // to Bethe-Bloch. The energy distribution of the delta electrons follows | |
676 | // a spectrum taken from Ermilova et al. | |
677 | // | |
678 | ||
851d3db9 | 679 | Int_t pla = 0; |
680 | Int_t cha = 0; | |
681 | Int_t sec = 0; | |
793ff80c | 682 | Int_t det = 0; |
851d3db9 | 683 | Int_t iPdg; |
793ff80c | 684 | Int_t qTot; |
5c7f4665 | 685 | |
793ff80c | 686 | Float_t hits[3]; |
a5cadd36 | 687 | Double_t random[1]; |
5c7f4665 | 688 | Float_t charge; |
689 | Float_t aMass; | |
690 | ||
030b4415 | 691 | Double_t pTot = 0.0; |
5c7f4665 | 692 | Double_t eDelta; |
030b4415 | 693 | Double_t betaGamma; |
694 | Double_t pp; | |
f73816f5 | 695 | Double_t stepSize; |
5c7f4665 | 696 | |
332e9569 | 697 | Bool_t drRegion = kFALSE; |
698 | Bool_t amRegion = kFALSE; | |
699 | ||
2c8bf4aa | 700 | TString cIdPath; |
701 | Char_t cIdSector[3]; | |
702 | cIdSector[2] = 0; | |
703 | ||
332e9569 | 704 | TString cIdCurrent; |
705 | TString cIdSensDr = "J"; | |
706 | TString cIdSensAm = "K"; | |
593a9fc3 | 707 | Char_t cIdChamber[3]; |
708 | cIdChamber[2] = 0; | |
332e9569 | 709 | |
030b4415 | 710 | TLorentzVector pos; |
711 | TLorentzVector mom; | |
82bbf98a | 712 | |
332e9569 | 713 | const Int_t kNplan = AliTRDgeometry::Nplan(); |
e644678a | 714 | const Int_t kNcham = AliTRDgeometry::Ncham(); |
715 | const Int_t kNdetsec = kNplan * kNcham; | |
716 | ||
030b4415 | 717 | const Double_t kBig = 1.0e+12; // Infinitely big |
bc327ce2 | 718 | const Float_t kWion = 23.53; // Ionization energy |
a328fff9 | 719 | const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g |
5c7f4665 | 720 | |
f73816f5 | 721 | // Minimum energy for the step size adjustment |
722 | const Float_t kEkinMinStep = 1.0e-5; | |
a328fff9 | 723 | |
5c7f4665 | 724 | // Plateau value of the energy-loss for electron in xenon |
030b4415 | 725 | // The averaged value (26/3/99) |
a3c76cdc | 726 | const Float_t kPlateau = 1.55; |
030b4415 | 727 | // dN1/dx|min for the gas mixture (90% Xe + 10% CO2) |
728 | const Float_t kPrim = 48.0; | |
5c7f4665 | 729 | // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2) |
a3c76cdc | 730 | const Float_t kPoti = 12.1; |
030b4415 | 731 | // PDG code electron |
732 | const Int_t kPdgElectron = 11; | |
5c7f4665 | 733 | |
734 | // Set the maximum step size to a very large number for all | |
735 | // neutral particles and those outside the driftvolume | |
736 | gMC->SetMaxStep(kBig); | |
737 | ||
738 | // Use only charged tracks | |
739 | if (( gMC->TrackCharge() ) && | |
5c7f4665 | 740 | (!gMC->IsTrackDisappeared())) { |
fe4da5cc | 741 | |
5c7f4665 | 742 | // Inside a sensitive volume? |
332e9569 | 743 | drRegion = kFALSE; |
744 | amRegion = kFALSE; | |
745 | cIdCurrent = gMC->CurrentVolName(); | |
e6674585 | 746 | if (cIdSensDr == cIdCurrent[1]) { |
332e9569 | 747 | drRegion = kTRUE; |
748 | } | |
e6674585 | 749 | if (cIdSensAm == cIdCurrent[1]) { |
332e9569 | 750 | amRegion = kTRUE; |
751 | } | |
752 | if (drRegion || amRegion) { | |
fe4da5cc | 753 | |
5c7f4665 | 754 | // The hit coordinates and charge |
755 | gMC->TrackPosition(pos); | |
756 | hits[0] = pos[0]; | |
757 | hits[1] = pos[1]; | |
758 | hits[2] = pos[2]; | |
5c7f4665 | 759 | |
2c8bf4aa | 760 | // The sector number (0 - 17), according to standard coordinate system |
761 | cIdPath = gGeoManager->GetPath(); | |
762 | cIdSector[0] = cIdPath[21]; | |
763 | cIdSector[1] = cIdPath[22]; | |
764 | sec = atoi(cIdSector); | |
82bbf98a | 765 | |
332e9569 | 766 | // The plane and chamber number |
767 | cIdChamber[0] = cIdCurrent[2]; | |
768 | cIdChamber[1] = cIdCurrent[3]; | |
e644678a | 769 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
8a497c18 | 770 | cha = ((Int_t) idChamber / kNplan); |
332e9569 | 771 | pla = ((Int_t) idChamber % kNplan); |
82bbf98a | 772 | |
ce0d6231 | 773 | // The detector number |
774 | det = fGeometry->GetDetector(pla,cha,sec); | |
5c7f4665 | 775 | |
ce0d6231 | 776 | // Special hits only in the drift region |
777 | if ((drRegion) && | |
778 | (gMC->IsTrackEntering())) { | |
5c7f4665 | 779 | |
ce0d6231 | 780 | // Create a track reference at the entrance of each |
781 | // chamber that contains the momentum components of the particle | |
782 | gMC->TrackMomentum(mom); | |
e6add757 | 783 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
793ff80c | 784 | |
ce0d6231 | 785 | // Create the hits from TR photons if electron/positron is |
786 | // entering the drift volume | |
787 | if ((fTR) && | |
788 | (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) { | |
789 | CreateTRhit(det); | |
790 | } | |
f73816f5 | 791 | |
ce0d6231 | 792 | } |
793 | else if ((amRegion) && | |
794 | (gMC->IsTrackExiting())) { | |
f73816f5 | 795 | |
ce0d6231 | 796 | // Create a track reference at the exit of each |
797 | // chamber that contains the momentum components of the particle | |
798 | gMC->TrackMomentum(mom); | |
e6add757 | 799 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
f73816f5 | 800 | |
ce0d6231 | 801 | } |
802 | ||
803 | // Calculate the energy of the delta-electrons | |
804 | eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti; | |
805 | eDelta = TMath::Max(eDelta,0.0); | |
806 | ||
807 | // Generate the electron cluster size | |
808 | if (eDelta > 0.0) { | |
809 | ||
810 | qTot = ((Int_t) (eDelta / kWion) + 1); | |
f73816f5 | 811 | |
030b4415 | 812 | // Create a new dEdx hit |
332e9569 | 813 | if (drRegion) { |
a328fff9 | 814 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 815 | ,det |
816 | ,hits | |
817 | ,qTot | |
25ca55ce | 818 | ,gMC->TrackTime()*1.0e06 |
030b4415 | 819 | ,kTRUE); |
820 | } | |
5c7f4665 | 821 | else { |
a328fff9 | 822 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() |
030b4415 | 823 | ,det |
824 | ,hits | |
825 | ,qTot | |
25ca55ce | 826 | ,gMC->TrackTime()*1.0e06 |
030b4415 | 827 | ,kFALSE); |
828 | } | |
f73816f5 | 829 | |
ce0d6231 | 830 | } |
831 | ||
832 | // Calculate the maximum step size for the next tracking step | |
833 | // Produce only one hit if Ekin is below cutoff | |
834 | aMass = gMC->TrackMass(); | |
835 | if ((gMC->Etot() - aMass) > kEkinMinStep) { | |
836 | ||
837 | // The energy loss according to Bethe Bloch | |
838 | iPdg = TMath::Abs(gMC->TrackPid()); | |
839 | if ((iPdg != kPdgElectron) || | |
840 | ((iPdg == kPdgElectron) && | |
841 | (pTot < kPTotMaxEl))) { | |
842 | gMC->TrackMomentum(mom); | |
843 | pTot = mom.Rho(); | |
844 | betaGamma = pTot / aMass; | |
845 | pp = kPrim * BetheBloch(betaGamma); | |
846 | // Take charge > 1 into account | |
847 | charge = gMC->TrackCharge(); | |
848 | if (TMath::Abs(charge) > 1) { | |
849 | pp = pp * charge*charge; | |
f73816f5 | 850 | } |
ce0d6231 | 851 | } |
852 | else { | |
853 | // Electrons above 20 Mev/c are at the plateau | |
854 | pp = kPrim * kPlateau; | |
855 | } | |
f73816f5 | 856 | |
ce0d6231 | 857 | if (pp > 0.0) { |
858 | do { | |
859 | gMC->GetRandom()->RndmArray(1,random); | |
030b4415 | 860 | } |
ce0d6231 | 861 | while ((random[0] == 1.0) || |
862 | (random[0] == 0.0)); | |
863 | stepSize = - TMath::Log(random[0]) / pp; | |
864 | gMC->SetMaxStep(stepSize); | |
865 | } | |
030b4415 | 866 | |
5c7f4665 | 867 | } |
030b4415 | 868 | |
d3f347ff | 869 | } |
030b4415 | 870 | |
5c7f4665 | 871 | } |
030b4415 | 872 | |
5c7f4665 | 873 | } |
874 | ||
a328fff9 | 875 | //_____________________________________________________________________________ |
876 | void AliTRDv1::StepManagerFixedStep() | |
877 | { | |
878 | // | |
879 | // Slow simulator. Every charged track produces electron cluster as hits | |
880 | // along its path across the drift volume. The step size is fixed in | |
881 | // this version of the step manager. | |
882 | // | |
883 | ||
ce0d6231 | 884 | // PDG code electron |
885 | const Int_t kPdgElectron = 11; | |
886 | ||
a328fff9 | 887 | Int_t pla = 0; |
888 | Int_t cha = 0; | |
889 | Int_t sec = 0; | |
890 | Int_t det = 0; | |
891 | Int_t qTot; | |
892 | ||
893 | Float_t hits[3]; | |
894 | Double_t eDep; | |
895 | ||
896 | Bool_t drRegion = kFALSE; | |
897 | Bool_t amRegion = kFALSE; | |
898 | ||
2c8bf4aa | 899 | TString cIdPath; |
900 | Char_t cIdSector[3]; | |
901 | cIdSector[2] = 0; | |
902 | ||
a328fff9 | 903 | TString cIdCurrent; |
904 | TString cIdSensDr = "J"; | |
905 | TString cIdSensAm = "K"; | |
906 | Char_t cIdChamber[3]; | |
2c8bf4aa | 907 | cIdChamber[2] = 0; |
a328fff9 | 908 | |
030b4415 | 909 | TLorentzVector pos; |
910 | TLorentzVector mom; | |
a328fff9 | 911 | |
912 | const Int_t kNplan = AliTRDgeometry::Nplan(); | |
913 | const Int_t kNcham = AliTRDgeometry::Ncham(); | |
914 | const Int_t kNdetsec = kNplan * kNcham; | |
915 | ||
030b4415 | 916 | const Double_t kBig = 1.0e+12; |
a328fff9 | 917 | |
bc327ce2 | 918 | const Float_t kWion = 23.53; // Ionization energy |
a328fff9 | 919 | const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment |
920 | ||
921 | // Set the maximum step size to a very large number for all | |
922 | // neutral particles and those outside the driftvolume | |
923 | gMC->SetMaxStep(kBig); | |
924 | ||
925 | // If not charged track or already stopped or disappeared, just return. | |
926 | if ((!gMC->TrackCharge()) || | |
ce0d6231 | 927 | gMC->IsTrackDisappeared()) { |
928 | return; | |
929 | } | |
a328fff9 | 930 | |
931 | // Inside a sensitive volume? | |
932 | cIdCurrent = gMC->CurrentVolName(); | |
933 | ||
ce0d6231 | 934 | if (cIdSensDr == cIdCurrent[1]) { |
935 | drRegion = kTRUE; | |
936 | } | |
937 | if (cIdSensAm == cIdCurrent[1]) { | |
938 | amRegion = kTRUE; | |
939 | } | |
a328fff9 | 940 | |
030b4415 | 941 | if ((!drRegion) && |
942 | (!amRegion)) { | |
943 | return; | |
944 | } | |
a328fff9 | 945 | |
946 | // The hit coordinates and charge | |
947 | gMC->TrackPosition(pos); | |
948 | hits[0] = pos[0]; | |
949 | hits[1] = pos[1]; | |
950 | hits[2] = pos[2]; | |
951 | ||
2c8bf4aa | 952 | // The sector number (0 - 17), according to standard coordinate system |
953 | cIdPath = gGeoManager->GetPath(); | |
954 | cIdSector[0] = cIdPath[21]; | |
955 | cIdSector[1] = cIdPath[22]; | |
956 | sec = atoi(cIdSector); | |
a328fff9 | 957 | |
958 | // The plane and chamber number | |
030b4415 | 959 | cIdChamber[0] = cIdCurrent[2]; |
960 | cIdChamber[1] = cIdCurrent[3]; | |
a328fff9 | 961 | Int_t idChamber = (atoi(cIdChamber) % kNdetsec); |
8a497c18 | 962 | cha = ((Int_t) idChamber / kNplan); |
a328fff9 | 963 | pla = ((Int_t) idChamber % kNplan); |
e0d47c25 | 964 | |
030b4415 | 965 | // The detector number |
966 | det = fGeometry->GetDetector(pla,cha,sec); | |
967 | ||
25ca55ce | 968 | // 0: InFlight 1:Entering 2:Exiting |
030b4415 | 969 | Int_t trkStat = 0; |
a328fff9 | 970 | |
971 | // Special hits only in the drift region | |
ce0d6231 | 972 | if ((drRegion) && |
973 | (gMC->IsTrackEntering())) { | |
a328fff9 | 974 | |
ce0d6231 | 975 | // Create a track reference at the entrance of each |
976 | // chamber that contains the momentum components of the particle | |
977 | gMC->TrackMomentum(mom); | |
e6add757 | 978 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
ce0d6231 | 979 | trkStat = 1; |
a328fff9 | 980 | |
ce0d6231 | 981 | // Create the hits from TR photons if electron/positron is |
982 | // entering the drift volume | |
983 | if ((fTR) && | |
984 | (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) { | |
030b4415 | 985 | CreateTRhit(det); |
986 | } | |
a328fff9 | 987 | |
ce0d6231 | 988 | } |
989 | else if ((amRegion) && | |
990 | (gMC->IsTrackExiting())) { | |
991 | ||
992 | // Create a track reference at the exit of each | |
993 | // chamber that contains the momentum components of the particle | |
994 | gMC->TrackMomentum(mom); | |
e6add757 | 995 | AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber(), AliTrackReference::kTRD); |
ce0d6231 | 996 | trkStat = 2; |
997 | ||
a328fff9 | 998 | } |
999 | ||
1000 | // Calculate the charge according to GEANT Edep | |
1001 | // Create a new dEdx hit | |
1002 | eDep = TMath::Max(gMC->Edep(),0.0) * 1.0e+09; | |
1003 | qTot = (Int_t) (eDep / kWion); | |
ce0d6231 | 1004 | if ((qTot) || |
1005 | (trkStat)) { | |
1006 | AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber() | |
1007 | ,det | |
1008 | ,hits | |
1009 | ,qTot | |
25ca55ce | 1010 | ,gMC->TrackTime()*1.0e06 |
ce0d6231 | 1011 | ,drRegion); |
1012 | } | |
a328fff9 | 1013 | |
1014 | // Set Maximum Step Size | |
1015 | // Produce only one hit if Ekin is below cutoff | |
030b4415 | 1016 | if ((gMC->Etot() - gMC->TrackMass()) < kEkinMinStep) { |
1017 | return; | |
1018 | } | |
a328fff9 | 1019 | gMC->SetMaxStep(fStepSize); |
1020 | ||
1021 | } | |
1022 | ||
5c7f4665 | 1023 | //_____________________________________________________________________________ |
1024 | Double_t AliTRDv1::BetheBloch(Double_t bg) | |
1025 | { | |
1026 | // | |
1027 | // Parametrization of the Bethe-Bloch-curve | |
1028 | // The parametrization is the same as for the TPC and is taken from Lehrhaus. | |
1029 | // | |
1030 | ||
1031 | // This parameters have been adjusted to averaged values from GEANT | |
f57bb418 | 1032 | const Double_t kP1 = 7.17960e-02; |
1033 | const Double_t kP2 = 8.54196; | |
1034 | const Double_t kP3 = 1.38065e-06; | |
1035 | const Double_t kP4 = 5.30972; | |
1036 | const Double_t kP5 = 2.83798; | |
5c7f4665 | 1037 | |
f73816f5 | 1038 | // Lower cutoff of the Bethe-Bloch-curve to limit step sizes |
1039 | const Double_t kBgMin = 0.8; | |
1040 | const Double_t kBBMax = 6.83298; | |
f73816f5 | 1041 | |
1042 | if (bg > kBgMin) { | |
030b4415 | 1043 | Double_t yy = bg / TMath::Sqrt(1.0 + bg*bg); |
5c7f4665 | 1044 | Double_t aa = TMath::Power(yy,kP4); |
030b4415 | 1045 | Double_t bb = TMath::Power((1.0/bg),kP5); |
5c7f4665 | 1046 | bb = TMath::Log(kP3 + bb); |
030b4415 | 1047 | return ((kP2 - aa - bb) * kP1 / aa); |
5c7f4665 | 1048 | } |
f73816f5 | 1049 | else { |
1050 | return kBBMax; | |
1051 | } | |
d3f347ff | 1052 | |
fe4da5cc | 1053 | } |
5c7f4665 | 1054 | |
a328fff9 | 1055 | //_____________________________________________________________________________ |
c4214bc0 | 1056 | Double_t AliTRDv1::BetheBlochGeant(Double_t bg) |
a328fff9 | 1057 | { |
1058 | // | |
1059 | // Return dN/dx (number of primary collisions per centimeter) | |
1060 | // for given beta*gamma factor. | |
1061 | // | |
1062 | // Implemented by K.Oyama according to GEANT 3 parametrization shown in | |
1063 | // A.Andronic's webpage: http://www-alice.gsi.de/trd/papers/dedx/dedx.html | |
1064 | // This must be used as a set with IntSpecGeant. | |
1065 | // | |
1066 | ||
030b4415 | 1067 | Int_t i = 0; |
a328fff9 | 1068 | |
030b4415 | 1069 | Double_t arrG[20] = { 1.100000, 1.200000, 1.300000, 1.500000 |
1070 | , 1.800000, 2.000000, 2.500000, 3.000000 | |
1071 | , 4.000000, 7.000000, 10.000000, 20.000000 | |
1072 | , 40.000000, 70.000000, 100.000000, 300.000000 | |
1073 | , 600.000000, 1000.000000, 3000.000000, 10000.000000 }; | |
a328fff9 | 1074 | |
030b4415 | 1075 | Double_t arrNC[20] = { 75.009056, 45.508083, 35.299252, 27.116327 |
1076 | , 22.734999, 21.411915, 19.934095, 19.449375 | |
1077 | , 19.344431, 20.185553, 21.027925, 22.912676 | |
1078 | , 24.933352, 26.504053, 27.387468, 29.566597 | |
1079 | , 30.353779, 30.787134, 31.129285, 31.157350 }; | |
1080 | ||
1081 | // Betagamma to gamma | |
1082 | Double_t g = TMath::Sqrt(1.0 + bg*bg); | |
a328fff9 | 1083 | |
1084 | // Find the index just before the point we need. | |
030b4415 | 1085 | for (i = 0; i < 18; i++) { |
1086 | if ((arrG[i] < g) && | |
1087 | (arrG[i+1] > g)) { | |
a328fff9 | 1088 | break; |
030b4415 | 1089 | } |
1090 | } | |
a328fff9 | 1091 | |
1092 | // Simple interpolation. | |
030b4415 | 1093 | Double_t pp = ((arrNC[i+1] - arrNC[i]) / (arrG[i+1] - arrG[i])) |
1094 | * (g - arrG[i]) + arrNC[i]; | |
a328fff9 | 1095 | |
030b4415 | 1096 | return pp; |
a328fff9 | 1097 | |
1098 | } | |
1099 | ||
5c7f4665 | 1100 | //_____________________________________________________________________________ |
1101 | Double_t Ermilova(Double_t *x, Double_t *) | |
1102 | { | |
1103 | // | |
1104 | // Calculates the delta-ray energy distribution according to Ermilova. | |
1105 | // Logarithmic scale ! | |
1106 | // | |
1107 | ||
1108 | Double_t energy; | |
1109 | Double_t dpos; | |
1110 | Double_t dnde; | |
1111 | ||
030b4415 | 1112 | Int_t pos1; |
1113 | Int_t pos2; | |
5c7f4665 | 1114 | |
8230f242 | 1115 | const Int_t kNv = 31; |
5c7f4665 | 1116 | |
030b4415 | 1117 | Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120 |
1118 | , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052 | |
1119 | , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915 | |
1120 | , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009 | |
1121 | , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103 | |
1122 | , 9.4727, 9.9035, 10.3735, 10.5966, 10.8198 | |
1123 | , 11.5129 }; | |
1124 | ||
1125 | Float_t vye[kNv] = { 80.0, 31.0, 23.3, 21.1, 21.0 | |
1126 | , 20.9, 20.8, 20.0, 16.0, 11.0 | |
1127 | , 8.0, 6.0, 5.2, 4.6, 4.0 | |
1128 | , 3.5, 3.0, 1.4, 0.67, 0.44 | |
1129 | , 0.3, 0.18, 0.12, 0.08, 0.056 | |
1130 | , 0.04, 0.023, 0.015, 0.011, 0.01 | |
1131 | , 0.004 }; | |
5c7f4665 | 1132 | |
1133 | energy = x[0]; | |
1134 | ||
1135 | // Find the position | |
030b4415 | 1136 | pos1 = 0; |
1137 | pos2 = 0; | |
5c7f4665 | 1138 | dpos = 0; |
1139 | do { | |
1140 | dpos = energy - vxe[pos2++]; | |
1141 | } | |
1142 | while (dpos > 0); | |
1143 | pos2--; | |
030b4415 | 1144 | if (pos2 > kNv) { |
1145 | pos2 = kNv - 1; | |
1146 | } | |
5c7f4665 | 1147 | pos1 = pos2 - 1; |
1148 | ||
1149 | // Differentiate between the sampling points | |
1150 | dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]); | |
1151 | ||
1152 | return dnde; | |
1153 | ||
1154 | } | |
a328fff9 | 1155 | |
1156 | //_____________________________________________________________________________ | |
1157 | Double_t IntSpecGeant(Double_t *x, Double_t *) | |
1158 | { | |
1159 | // | |
1160 | // Integrated spectrum from Geant3 | |
1161 | // | |
1162 | ||
96efaf83 | 1163 | const Int_t npts = 83; |
030b4415 | 1164 | Double_t arre[npts] = { 2.421257, 2.483278, 2.534301, 2.592230 |
1165 | , 2.672067, 2.813299, 3.015059, 3.216819 | |
1166 | , 3.418579, 3.620338, 3.868209, 3.920198 | |
1167 | , 3.978284, 4.063923, 4.186264, 4.308605 | |
1168 | , 4.430946, 4.553288, 4.724261, 4.837736 | |
1169 | , 4.999842, 5.161949, 5.324056, 5.486163 | |
1170 | , 5.679688, 5.752998, 5.857728, 5.962457 | |
1171 | , 6.067185, 6.171914, 6.315653, 6.393674 | |
1172 | , 6.471694, 6.539689, 6.597658, 6.655627 | |
1173 | , 6.710957, 6.763648, 6.816338, 6.876198 | |
1174 | , 6.943227, 7.010257, 7.106285, 7.252151 | |
1175 | , 7.460531, 7.668911, 7.877290, 8.085670 | |
1176 | , 8.302979, 8.353585, 8.413120, 8.483500 | |
1177 | , 8.541030, 8.592857, 8.668865, 8.820485 | |
1178 | , 9.037086, 9.253686, 9.470286, 9.686887 | |
1179 | , 9.930838, 9.994655, 10.085822, 10.176990 | |
1180 | , 10.268158, 10.359325, 10.503614, 10.627565 | |
1181 | , 10.804637, 10.981709, 11.158781, 11.335854 | |
1182 | , 11.593397, 11.781165, 12.049404, 12.317644 | |
1183 | , 12.585884, 12.854123, 14.278421, 16.975889 | |
1184 | , 20.829416, 24.682943, 28.536469 }; | |
1185 | ||
1186 | Double_t arrdnde[npts] = { 10.960000, 10.960000, 10.359500, 9.811340 | |
1187 | , 9.1601500, 8.206670, 6.919630, 5.655430 | |
1188 | , 4.6221300, 3.777610, 3.019560, 2.591950 | |
1189 | , 2.5414600, 2.712920, 3.327460, 4.928240 | |
1190 | , 7.6185300, 10.966700, 12.225800, 8.094750 | |
1191 | , 3.3586900, 1.553650, 1.209600, 1.263840 | |
1192 | , 1.3241100, 1.312140, 1.255130, 1.165770 | |
1193 | , 1.0594500, 0.945450, 0.813231, 0.699837 | |
1194 | , 0.6235580, 2.260990, 2.968350, 2.240320 | |
1195 | , 1.7988300, 1.553300, 1.432070, 1.535520 | |
1196 | , 1.4429900, 1.247990, 1.050750, 0.829549 | |
1197 | , 0.5900280, 0.395897, 0.268741, 0.185320 | |
1198 | , 0.1292120, 0.103545, 0.0949525, 0.101535 | |
1199 | , 0.1276380, 0.134216, 0.123816, 0.104557 | |
1200 | , 0.0751843, 0.0521745, 0.0373546, 0.0275391 | |
1201 | , 0.0204713, 0.0169234, 0.0154552, 0.0139194 | |
1202 | , 0.0125592, 0.0113638, 0.0107354, 0.0102137 | |
1203 | , 0.00845984, 0.00683338, 0.00556836, 0.00456874 | |
1204 | , 0.0036227, 0.00285991, 0.00226664, 0.00172234 | |
1205 | , 0.00131226, 0.00100284, 0.000465492, 7.26607e-05 | |
1206 | , 3.63304e-06, 0.0000000, 0.0000000 }; | |
1207 | ||
1208 | Int_t i; | |
a328fff9 | 1209 | Double_t energy = x[0]; |
a328fff9 | 1210 | |
225211c8 | 1211 | if (energy >= arre[npts-1]) { |
1212 | return 0.0; | |
1213 | } | |
1214 | ||
030b4415 | 1215 | for (i = 0; i < npts; i++) { |
1216 | if (energy < arre[i]) { | |
1217 | break; | |
1218 | } | |
1219 | } | |
a328fff9 | 1220 | |
030b4415 | 1221 | if (i == 0) { |
1222 | AliErrorGeneral("AliTRDv1::IntSpecGeant","Given energy value is too small or zero"); | |
1223 | } | |
a328fff9 | 1224 | |
f57bb418 | 1225 | return arrdnde[i]; |
a328fff9 | 1226 | |
1227 | } |