Remove AliTRDtimeBin
[u/mrichter/AliRoot.git] / TRD / AliTRDv1.cxx
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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"
37#include "AliMC.h"
88cb7938 38#include "AliRun.h"
030b4415 39
88cb7938 40#include "AliTRDgeometry.h"
793ff80c 41#include "AliTRDhit.h"
793ff80c 42#include "AliTRDsim.h"
88cb7938 43#include "AliTRDv1.h"
851d3db9 44
fe4da5cc 45ClassImp(AliTRDv1)
8230f242 46
47//_____________________________________________________________________________
030b4415 48AliTRDv1::AliTRDv1()
49 :AliTRD()
50 ,fTRon(kFALSE)
51 ,fTR(NULL)
52 ,fTypeOfStepManager(0)
53 ,fStepSize(0)
54 ,fDeltaE(NULL)
55 ,fDeltaG(NULL)
56 ,fTrackLength0(0)
57 ,fPrimaryTrackPid(0)
8230f242 58{
59 //
60 // Default constructor
61 //
62
8230f242 63}
64
fe4da5cc 65//_____________________________________________________________________________
66AliTRDv1::AliTRDv1(const char *name, const char *title)
030b4415 67 :AliTRD(name,title)
68 ,fTRon(kTRUE)
69 ,fTR(NULL)
67c47633 70 ,fTypeOfStepManager(2)
030b4415 71 ,fStepSize(0.1)
72 ,fDeltaE(NULL)
73 ,fDeltaG(NULL)
74 ,fTrackLength0(0)
75 ,fPrimaryTrackPid(0)
fe4da5cc 76{
77 //
851d3db9 78 // Standard constructor for Transition Radiation Detector version 1
fe4da5cc 79 //
82bbf98a 80
5c7f4665 81 SetBufferSize(128000);
82
83}
84
85//_____________________________________________________________________________
86AliTRDv1::~AliTRDv1()
87{
dd9a6ee3 88 //
89 // AliTRDv1 destructor
90 //
82bbf98a 91
030b4415 92 if (fDeltaE) {
93 delete fDeltaE;
94 fDeltaE = 0;
95 }
96
97 if (fDeltaG) {
98 delete fDeltaG;
99 fDeltaG = 0;
100 }
101
102 if (fTR) {
103 delete fTR;
104 fTR = 0;
105 }
82bbf98a 106
fe4da5cc 107}
108
dd9a6ee3 109//_____________________________________________________________________________
f57bb418 110void AliTRDv1::AddAlignableVolumes() const
111{
112 //
113 // Create entries for alignable volumes associating the symbolic volume
114 // name with the corresponding volume path. Needs to be syncronized with
115 // eventual changes in the geometry.
116 //
117
118 TString volPath;
119 TString symName;
120
121 TString vpStr = "ALIC_1/B077_1/BSEGMO";
122 TString vpApp1 = "_1/BTRD";
123 TString vpApp2 = "_1";
124 TString vpApp3 = "/UTR1_1/UTS1_1/UTI1_1/UT";
125
126 TString snStr = "TRD/sm";
127 TString snApp1 = "/st";
128 TString snApp2 = "/pl";
129
130 //
131 // The super modules
132 // The symbolic names are: TRD/sm00
133 // ...
134 // TRD/sm17
135 //
136 for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) {
137
138 volPath = vpStr;
139 volPath += isect;
140 volPath += vpApp1;
141 volPath += isect;
142 volPath += vpApp2;
143
144 symName = snStr;
145 symName += Form("%02d",isect);
146
147 gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data());
148
149 }
150
151 //
152 // The readout chambers
153 // The symbolic names are: TRD/sm00/st0/pl0
154 // ...
155 // TRD/sm17/st4/pl5
156 //
157 for (Int_t isect = 0; isect < AliTRDgeometry::Nsect(); isect++) {
158 for (Int_t icham = 0; icham < AliTRDgeometry::Ncham(); icham++) {
159 for (Int_t iplan = 0; iplan < AliTRDgeometry::Nplan(); iplan++) {
160
161 Int_t idet = AliTRDgeometry::GetDetectorSec(iplan,icham);
162
163 volPath = vpStr;
164 volPath += isect;
165 volPath += vpApp1;
166 volPath += isect;
167 volPath += vpApp2;
168 volPath += vpApp3;
169 volPath += Form("%02d",idet);
170 volPath += vpApp2;
171
172 symName = snStr;
173 symName += Form("%02d",isect);
174 symName += snApp1;
175 symName += icham;
176 symName += snApp2;
177 symName += iplan;
178
51a5f1d0 179 TGeoPNEntry *alignableEntry =
180 gGeoManager->SetAlignableEntry(symName.Data(),volPath.Data());
f57bb418 181
170c35f1 182 // Add the tracking to local matrix following the TPC example
170c35f1 183
51a5f1d0 184 if (alignableEntry) {
185 const char *path = alignableEntry->GetTitle();
186 if (!gGeoManager->cd(path)) {
187 AliFatal(Form("Volume path %s not valid!",path));
188 }
189 TGeoHMatrix *globMatrix = gGeoManager->GetCurrentMatrix();
190 Double_t sectorAngle = 20.0 * (isect % 18) + 10.0;
191 TGeoHMatrix *t2lMatrix = new TGeoHMatrix();
192 t2lMatrix->RotateZ(sectorAngle);
193 t2lMatrix->MultiplyLeft(&(globMatrix->Inverse()));
194 alignableEntry->SetMatrix(t2lMatrix);
195 }
196 else {
197 AliError(Form("Alignable entry %s is not valid!",symName.Data()));
198 }
f57bb418 199 }
200 }
201 }
202
203}
204
205//_____________________________________________________________________________
fe4da5cc 206void AliTRDv1::CreateGeometry()
207{
208 //
851d3db9 209 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
5c7f4665 210 // This version covers the full azimuth.
d3f347ff 211 //
212
82bbf98a 213 // Check that FRAME is there otherwise we have no place where to put the TRD
8230f242 214 AliModule* frame = gAlice->GetModule("FRAME");
030b4415 215 if (!frame) {
216 AliError("TRD needs FRAME to be present\n");
217 return;
218 }
d3f347ff 219
82bbf98a 220 // Define the chambers
221 AliTRD::CreateGeometry();
d3f347ff 222
fe4da5cc 223}
224
225//_____________________________________________________________________________
226void AliTRDv1::CreateMaterials()
227{
228 //
851d3db9 229 // Create materials for the Transition Radiation Detector version 1
fe4da5cc 230 //
82bbf98a 231
d3f347ff 232 AliTRD::CreateMaterials();
82bbf98a 233
fe4da5cc 234}
235
236//_____________________________________________________________________________
793ff80c 237void AliTRDv1::CreateTRhit(Int_t det)
238{
239 //
240 // Creates an electron cluster from a TR photon.
241 // The photon is assumed to be created a the end of the radiator. The
242 // distance after which it deposits its energy takes into account the
243 // absorbtion of the entrance window and of the gas mixture in drift
244 // volume.
245 //
246
793ff80c 247 // Ionization energy
bc327ce2 248 const Float_t kWion = 23.53;
793ff80c 249
250 // Maximum number of TR photons per track
251 const Int_t kNTR = 50;
252
030b4415 253 TLorentzVector mom;
254 TLorentzVector pos;
793ff80c 255
ce0d6231 256 Float_t eTR[kNTR];
257 Int_t nTR;
793ff80c 258
ce0d6231 259 // Create TR photons
260 gMC->TrackMomentum(mom);
261 Float_t pTot = mom.Rho();
262 fTR->CreatePhotons(11,pTot,nTR,eTR);
263 if (nTR > kNTR) {
264 AliFatal(Form("Boundary error: nTR = %d, kNTR = %d",nTR,kNTR));
265 }
f73816f5 266
ce0d6231 267 // Loop through the TR photons
268 for (Int_t iTR = 0; iTR < nTR; iTR++) {
793ff80c 269
ce0d6231 270 Float_t energyMeV = eTR[iTR] * 0.001;
271 Float_t energyeV = eTR[iTR] * 1000.0;
272 Float_t absLength = 0.0;
273 Float_t sigma = 0.0;
793ff80c 274
ce0d6231 275 // Take the absorbtion in the entrance window into account
276 Double_t muMy = fTR->GetMuMy(energyMeV);
277 sigma = muMy * fFoilDensity;
278 if (sigma > 0.0) {
279 absLength = gRandom->Exp(1.0/sigma);
280 if (absLength < AliTRDgeometry::MyThick()) {
842287f2 281 continue;
282 }
ce0d6231 283 }
284 else {
285 continue;
286 }
793ff80c 287
ce0d6231 288 // The absorbtion cross sections in the drift gas
289 // Gas-mixture (Xe/CO2)
290 Double_t muXe = fTR->GetMuXe(energyMeV);
291 Double_t muCO = fTR->GetMuCO(energyMeV);
292 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity * fTR->GetTemp();
293
294 // The distance after which the energy of the TR photon
295 // is deposited.
296 if (sigma > 0.0) {
297 absLength = gRandom->Exp(1.0/sigma);
298 if (absLength > (AliTRDgeometry::DrThick()
299 + AliTRDgeometry::AmThick())) {
842287f2 300 continue;
301 }
ce0d6231 302 }
303 else {
304 continue;
305 }
793ff80c 306
ce0d6231 307 // The position of the absorbtion
308 Float_t posHit[3];
309 gMC->TrackPosition(pos);
310 posHit[0] = pos[0] + mom[0] / pTot * absLength;
311 posHit[1] = pos[1] + mom[1] / pTot * absLength;
312 posHit[2] = pos[2] + mom[2] / pTot * absLength;
793ff80c 313
ce0d6231 314 // Create the charge
315 Int_t q = ((Int_t) (energyeV / kWion));
793ff80c 316
ce0d6231 317 // Add the hit to the array. TR photon hits are marked
318 // by negative charge
319 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
320 ,det
321 ,posHit
322 ,-q
25ca55ce 323 ,gMC->TrackTime()*1.0e06
d4c6453d 324 ,kTRUE);
793ff80c 325
326 }
327
328}
329
330//_____________________________________________________________________________
5c7f4665 331void AliTRDv1::Init()
332{
333 //
334 // Initialise Transition Radiation Detector after geometry has been built.
5c7f4665 335 //
336
337 AliTRD::Init();
338
45160b1f 339 AliDebug(1,"Slow simulator\n");
bd0f8685 340
341 // Switch on TR simulation as default
342 if (!fTRon) {
45160b1f 343 AliInfo("TR simulation off");
bd0f8685 344 }
345 else {
346 fTR = new AliTRDsim();
347 }
5c7f4665 348
349 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
350 const Float_t kPoti = 12.1;
351 // Maximum energy (50 keV);
352 const Float_t kEend = 50000.0;
353 // Ermilova distribution for the delta-ray spectrum
030b4415 354 Float_t poti = TMath::Log(kPoti);
355 Float_t eEnd = TMath::Log(kEend);
a328fff9 356
357 // Ermilova distribution for the delta-ray spectrum
c4214bc0 358 fDeltaE = new TF1("deltae" ,Ermilova ,poti,eEnd,0);
a328fff9 359
360 // Geant3 distribution for the delta-ray spectrum
c4214bc0 361 fDeltaG = new TF1("deltag",IntSpecGeant,2.421257,28.536469,0);
5c7f4665 362
45160b1f 363 AliDebug(1,"+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++");
5c7f4665 364
fe4da5cc 365}
366
367//_____________________________________________________________________________
5c7f4665 368void AliTRDv1::StepManager()
369{
370 //
c4214bc0 371 // Slow simulator. Every charged track produces electron cluster as hits
a328fff9 372 // along its path across the drift volume.
373 //
374
375 switch (fTypeOfStepManager) {
a6dd11e9 376 case 0:
377 StepManagerErmilova();
378 break;
379 case 1:
380 StepManagerGeant();
381 break;
382 case 2:
383 StepManagerFixedStep();
384 break;
385 default:
386 AliWarning("Not a valid Step Manager.");
a328fff9 387 }
388
389}
390
391//_____________________________________________________________________________
392void AliTRDv1::SelectStepManager(Int_t t)
393{
394 //
395 // Selects a step manager type:
396 // 0 - Ermilova
397 // 1 - Geant3
398 // 2 - Fixed step size
399 //
400
a328fff9 401 fTypeOfStepManager = t;
45160b1f 402 AliInfo(Form("Step Manager type %d was selected",fTypeOfStepManager));
a328fff9 403
404}
405
406//_____________________________________________________________________________
407void AliTRDv1::StepManagerGeant()
408{
409 //
c4214bc0 410 // Slow simulator. Every charged track produces electron cluster as hits
a328fff9 411 // along its path across the drift volume. The step size is set acording
412 // to Bethe-Bloch. The energy distribution of the delta electrons follows
413 // a spectrum taken from Geant3.
414 //
f2e3a0b5 415 // Version by A. Bercuci
416 //
417
c4214bc0 418 Int_t pla = 0;
419 Int_t cha = 0;
420 Int_t sec = 0;
421 Int_t det = 0;
422 Int_t iPdg;
423 Int_t qTot;
424
425 Float_t hits[3];
426 Float_t charge;
427 Float_t aMass;
428
030b4415 429 Double_t pTot = 0;
c4214bc0 430 Double_t eDelta;
030b4415 431 Double_t betaGamma;
432 Double_t pp;
f2e3a0b5 433 Double_t stepSize = 0;
c4214bc0 434
435 Bool_t drRegion = kFALSE;
436 Bool_t amRegion = kFALSE;
437
2c8bf4aa 438 TString cIdPath;
439 Char_t cIdSector[3];
440 cIdSector[2] = 0;
441
c4214bc0 442 TString cIdCurrent;
443 TString cIdSensDr = "J";
444 TString cIdSensAm = "K";
445 Char_t cIdChamber[3];
446 cIdChamber[2] = 0;
447
030b4415 448 TLorentzVector pos;
449 TLorentzVector mom;
c4214bc0 450
030b4415 451 TArrayI processes;
f2e3a0b5 452
c4214bc0 453 const Int_t kNplan = AliTRDgeometry::Nplan();
454 const Int_t kNcham = AliTRDgeometry::Ncham();
455 const Int_t kNdetsec = kNplan * kNcham;
456
030b4415 457 const Double_t kBig = 1.0e+12; // Infinitely big
bc327ce2 458 const Float_t kWion = 23.53; // Ionization energy
c4214bc0 459 const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g
460
461 // Minimum energy for the step size adjustment
462 const Float_t kEkinMinStep = 1.0e-5;
463 // energy threshold for production of delta electrons
f2e3a0b5 464 const Float_t kECut = 1.0e4;
465 // Parameters entering the parametrized range for delta electrons
030b4415 466 const Float_t kRa = 5.37e-4;
f2e3a0b5 467 const Float_t kRb = 0.9815;
030b4415 468 const Float_t kRc = 3.123e-3;
f2e3a0b5 469 // Gas density -> To be made user adjustable !
030b4415 470 // [0.85*0.00549+0.15*0.00186 (Xe-CO2 85-15)]
471 const Float_t kRho = 0.004945 ;
a328fff9 472
c4214bc0 473 // Plateau value of the energy-loss for electron in xenon
030b4415 474 // The averaged value (26/3/99)
c4214bc0 475 const Float_t kPlateau = 1.55;
030b4415 476 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
477 const Float_t kPrim = 19.34;
c4214bc0 478 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
479 const Float_t kPoti = 12.1;
030b4415 480 // PDG code electron
481 const Int_t kPdgElectron = 11;
c4214bc0 482
483 // Set the maximum step size to a very large number for all
484 // neutral particles and those outside the driftvolume
485 gMC->SetMaxStep(kBig);
486
487 // Use only charged tracks
488 if (( gMC->TrackCharge() ) &&
c4214bc0 489 (!gMC->IsTrackDisappeared())) {
490
491 // Inside a sensitive volume?
492 drRegion = kFALSE;
493 amRegion = kFALSE;
494 cIdCurrent = gMC->CurrentVolName();
495 if (cIdSensDr == cIdCurrent[1]) {
496 drRegion = kTRUE;
497 }
498 if (cIdSensAm == cIdCurrent[1]) {
499 amRegion = kTRUE;
500 }
501 if (drRegion || amRegion) {
a328fff9 502
c4214bc0 503 // The hit coordinates and charge
504 gMC->TrackPosition(pos);
505 hits[0] = pos[0];
506 hits[1] = pos[1];
507 hits[2] = pos[2];
508
2c8bf4aa 509 // The sector number (0 - 17), according to standard coordinate system
510 cIdPath = gGeoManager->GetPath();
511 cIdSector[0] = cIdPath[21];
512 cIdSector[1] = cIdPath[22];
513 sec = atoi(cIdSector);
c4214bc0 514
515 // The plane and chamber number
030b4415 516 cIdChamber[0] = cIdCurrent[2];
517 cIdChamber[1] = cIdCurrent[3];
c4214bc0 518 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
8a497c18 519 cha = ((Int_t) idChamber / kNplan);
c4214bc0 520 pla = ((Int_t) idChamber % kNplan);
521
ce0d6231 522 // The detector number
523 det = fGeometry->GetDetector(pla,cha,sec);
c4214bc0 524
ce0d6231 525 // Special hits only in the drift region
526 if ((drRegion) &&
527 (gMC->IsTrackEntering())) {
c4214bc0 528
ce0d6231 529 // Create a track reference at the entrance of each
530 // chamber that contains the momentum components of the particle
531 gMC->TrackMomentum(mom);
532 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
c4214bc0 533
ce0d6231 534 // Create the hits from TR photons if electron/positron is
535 // entering the drift volume
536 if ((fTR) &&
537 (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
538 CreateTRhit(det);
539 }
f2e3a0b5 540
ce0d6231 541 }
542 else if ((amRegion) &&
543 (gMC->IsTrackExiting())) {
f2e3a0b5 544
ce0d6231 545 // Create a track reference at the exit of each
546 // chamber that contains the momentum components of the particle
547 gMC->TrackMomentum(mom);
548 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
c4214bc0 549
ce0d6231 550 }
c4214bc0 551
ce0d6231 552 // Calculate the energy of the delta-electrons
553 // modified by Alex Bercuci (A.Bercuci@gsi.de) on 26.01.06
554 // take into account correlation with the underlying GEANT tracking
555 // mechanism. see
556 // http://www-linux.gsi.de/~abercuci/Contributions/TRD/index.html
557 //
558 // determine the most significant process (last on the processes list)
559 // which caused this hit
560 gMC->StepProcesses(processes);
561 Int_t nofprocesses = processes.GetSize();
562 Int_t pid;
563 if (!nofprocesses) {
564 pid = 0;
565 }
566 else {
567 pid = processes[nofprocesses-1];
568 }
f2e3a0b5 569
ce0d6231 570 // Generate Edep according to GEANT parametrisation
571 eDelta = TMath::Exp(fDeltaG->GetRandom()) - kPoti;
572 eDelta = TMath::Max(eDelta,0.0);
573 Float_t prRange = 0.0;
574 Float_t range = gMC->TrackLength() - fTrackLength0;
575 // merge GEANT tracker information with locally cooked one
576 if (gAlice->GetMCApp()->GetCurrentTrackNumber() == fPrimaryTrackPid) {
577 if (pid == 27) {
578 if (eDelta >= kECut) {
579 prRange = kRa * eDelta * 0.001
580 * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho;
581 if (prRange >= (3.7 - range)) {
582 eDelta *= 0.1;
583 }
584 }
585 }
586 else if (pid == 1) {
587 if (eDelta < kECut) {
588 eDelta *= 0.5;
589 }
590 else {
591 prRange = kRa * eDelta * 0.001
592 * (1.0 - kRb / (1.0 + kRc * eDelta * 0.001)) / kRho;
593 if (prRange >= ((AliTRDgeometry::DrThick()
594 + AliTRDgeometry::AmThick()) - range)) {
595 eDelta *= 0.05;
596 }
597 else {
f2e3a0b5 598 eDelta *= 0.5;
ce0d6231 599 }
600 }
601 }
f2e3a0b5 602 else {
603 eDelta = 0.0;
ce0d6231 604 }
605 }
606 else {
607 eDelta = 0.0;
608 }
c4214bc0 609
ce0d6231 610 // Generate the electron cluster size
611 if (eDelta > 0.0) {
f2e3a0b5 612
ce0d6231 613 qTot = ((Int_t) (eDelta / kWion) + 1);
614
615 // Create a new dEdx hit
030b4415 616 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
617 ,det
618 ,hits
619 ,qTot
25ca55ce 620 ,gMC->TrackTime()*1.0e06
030b4415 621 ,drRegion);
c4214bc0 622
ce0d6231 623 }
624
625 // Calculate the maximum step size for the next tracking step
626 // Produce only one hit if Ekin is below cutoff
627 aMass = gMC->TrackMass();
628 if ((gMC->Etot() - aMass) > kEkinMinStep) {
629
630 // The energy loss according to Bethe Bloch
631 iPdg = TMath::Abs(gMC->TrackPid());
632 if ((iPdg != kPdgElectron) ||
633 ((iPdg == kPdgElectron) &&
634 (pTot < kPTotMaxEl))) {
635 gMC->TrackMomentum(mom);
636 pTot = mom.Rho();
637 betaGamma = pTot / aMass;
638 pp = BetheBlochGeant(betaGamma);
639 // Take charge > 1 into account
640 charge = gMC->TrackCharge();
641 if (TMath::Abs(charge) > 1) {
642 pp = pp * charge*charge;
643 }
644 }
645 else {
646 // Electrons above 20 Mev/c are at the plateau
647 pp = kPrim * kPlateau;
648 }
f2e3a0b5 649
ce0d6231 650 Int_t nsteps = 0;
651 do {
652 nsteps = gRandom->Poisson(pp);
653 } while(!nsteps);
654 stepSize = 1.0 / nsteps;
655 gMC->SetMaxStep(stepSize);
f2e3a0b5 656
c4214bc0 657 }
f2e3a0b5 658
c4214bc0 659 }
f2e3a0b5 660
c4214bc0 661 }
f2e3a0b5 662
a328fff9 663}
664
665//_____________________________________________________________________________
666void AliTRDv1::StepManagerErmilova()
667{
668 //
669 // Slow simulator. Every charged track produces electron cluster as hits
5c7f4665 670 // along its path across the drift volume. The step size is set acording
671 // to Bethe-Bloch. The energy distribution of the delta electrons follows
672 // a spectrum taken from Ermilova et al.
673 //
674
851d3db9 675 Int_t pla = 0;
676 Int_t cha = 0;
677 Int_t sec = 0;
793ff80c 678 Int_t det = 0;
851d3db9 679 Int_t iPdg;
793ff80c 680 Int_t qTot;
5c7f4665 681
793ff80c 682 Float_t hits[3];
a5cadd36 683 Double_t random[1];
5c7f4665 684 Float_t charge;
685 Float_t aMass;
686
030b4415 687 Double_t pTot = 0.0;
5c7f4665 688 Double_t eDelta;
030b4415 689 Double_t betaGamma;
690 Double_t pp;
f73816f5 691 Double_t stepSize;
5c7f4665 692
332e9569 693 Bool_t drRegion = kFALSE;
694 Bool_t amRegion = kFALSE;
695
2c8bf4aa 696 TString cIdPath;
697 Char_t cIdSector[3];
698 cIdSector[2] = 0;
699
332e9569 700 TString cIdCurrent;
701 TString cIdSensDr = "J";
702 TString cIdSensAm = "K";
593a9fc3 703 Char_t cIdChamber[3];
704 cIdChamber[2] = 0;
332e9569 705
030b4415 706 TLorentzVector pos;
707 TLorentzVector mom;
82bbf98a 708
332e9569 709 const Int_t kNplan = AliTRDgeometry::Nplan();
e644678a 710 const Int_t kNcham = AliTRDgeometry::Ncham();
711 const Int_t kNdetsec = kNplan * kNcham;
712
030b4415 713 const Double_t kBig = 1.0e+12; // Infinitely big
bc327ce2 714 const Float_t kWion = 23.53; // Ionization energy
a328fff9 715 const Float_t kPTotMaxEl = 0.002; // Maximum momentum for e+ e- g
5c7f4665 716
f73816f5 717 // Minimum energy for the step size adjustment
718 const Float_t kEkinMinStep = 1.0e-5;
a328fff9 719
5c7f4665 720 // Plateau value of the energy-loss for electron in xenon
030b4415 721 // The averaged value (26/3/99)
a3c76cdc 722 const Float_t kPlateau = 1.55;
030b4415 723 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
724 const Float_t kPrim = 48.0;
5c7f4665 725 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
a3c76cdc 726 const Float_t kPoti = 12.1;
030b4415 727 // PDG code electron
728 const Int_t kPdgElectron = 11;
5c7f4665 729
730 // Set the maximum step size to a very large number for all
731 // neutral particles and those outside the driftvolume
732 gMC->SetMaxStep(kBig);
733
734 // Use only charged tracks
735 if (( gMC->TrackCharge() ) &&
5c7f4665 736 (!gMC->IsTrackDisappeared())) {
fe4da5cc 737
5c7f4665 738 // Inside a sensitive volume?
332e9569 739 drRegion = kFALSE;
740 amRegion = kFALSE;
741 cIdCurrent = gMC->CurrentVolName();
e6674585 742 if (cIdSensDr == cIdCurrent[1]) {
332e9569 743 drRegion = kTRUE;
744 }
e6674585 745 if (cIdSensAm == cIdCurrent[1]) {
332e9569 746 amRegion = kTRUE;
747 }
748 if (drRegion || amRegion) {
fe4da5cc 749
5c7f4665 750 // The hit coordinates and charge
751 gMC->TrackPosition(pos);
752 hits[0] = pos[0];
753 hits[1] = pos[1];
754 hits[2] = pos[2];
5c7f4665 755
2c8bf4aa 756 // The sector number (0 - 17), according to standard coordinate system
757 cIdPath = gGeoManager->GetPath();
758 cIdSector[0] = cIdPath[21];
759 cIdSector[1] = cIdPath[22];
760 sec = atoi(cIdSector);
82bbf98a 761
332e9569 762 // The plane and chamber number
763 cIdChamber[0] = cIdCurrent[2];
764 cIdChamber[1] = cIdCurrent[3];
e644678a 765 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
8a497c18 766 cha = ((Int_t) idChamber / kNplan);
332e9569 767 pla = ((Int_t) idChamber % kNplan);
82bbf98a 768
ce0d6231 769 // The detector number
770 det = fGeometry->GetDetector(pla,cha,sec);
5c7f4665 771
ce0d6231 772 // Special hits only in the drift region
773 if ((drRegion) &&
774 (gMC->IsTrackEntering())) {
5c7f4665 775
ce0d6231 776 // Create a track reference at the entrance of each
777 // chamber that contains the momentum components of the particle
778 gMC->TrackMomentum(mom);
779 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
793ff80c 780
ce0d6231 781 // Create the hits from TR photons if electron/positron is
782 // entering the drift volume
783 if ((fTR) &&
784 (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
785 CreateTRhit(det);
786 }
f73816f5 787
ce0d6231 788 }
789 else if ((amRegion) &&
790 (gMC->IsTrackExiting())) {
f73816f5 791
ce0d6231 792 // Create a track reference at the exit of each
793 // chamber that contains the momentum components of the particle
794 gMC->TrackMomentum(mom);
795 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
f73816f5 796
ce0d6231 797 }
798
799 // Calculate the energy of the delta-electrons
800 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
801 eDelta = TMath::Max(eDelta,0.0);
802
803 // Generate the electron cluster size
804 if (eDelta > 0.0) {
805
806 qTot = ((Int_t) (eDelta / kWion) + 1);
f73816f5 807
030b4415 808 // Create a new dEdx hit
332e9569 809 if (drRegion) {
a328fff9 810 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
030b4415 811 ,det
812 ,hits
813 ,qTot
25ca55ce 814 ,gMC->TrackTime()*1.0e06
030b4415 815 ,kTRUE);
816 }
5c7f4665 817 else {
a328fff9 818 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
030b4415 819 ,det
820 ,hits
821 ,qTot
25ca55ce 822 ,gMC->TrackTime()*1.0e06
030b4415 823 ,kFALSE);
824 }
f73816f5 825
ce0d6231 826 }
827
828 // Calculate the maximum step size for the next tracking step
829 // Produce only one hit if Ekin is below cutoff
830 aMass = gMC->TrackMass();
831 if ((gMC->Etot() - aMass) > kEkinMinStep) {
832
833 // The energy loss according to Bethe Bloch
834 iPdg = TMath::Abs(gMC->TrackPid());
835 if ((iPdg != kPdgElectron) ||
836 ((iPdg == kPdgElectron) &&
837 (pTot < kPTotMaxEl))) {
838 gMC->TrackMomentum(mom);
839 pTot = mom.Rho();
840 betaGamma = pTot / aMass;
841 pp = kPrim * BetheBloch(betaGamma);
842 // Take charge > 1 into account
843 charge = gMC->TrackCharge();
844 if (TMath::Abs(charge) > 1) {
845 pp = pp * charge*charge;
f73816f5 846 }
ce0d6231 847 }
848 else {
849 // Electrons above 20 Mev/c are at the plateau
850 pp = kPrim * kPlateau;
851 }
f73816f5 852
ce0d6231 853 if (pp > 0.0) {
854 do {
855 gMC->GetRandom()->RndmArray(1,random);
030b4415 856 }
ce0d6231 857 while ((random[0] == 1.0) ||
858 (random[0] == 0.0));
859 stepSize = - TMath::Log(random[0]) / pp;
860 gMC->SetMaxStep(stepSize);
861 }
030b4415 862
5c7f4665 863 }
030b4415 864
d3f347ff 865 }
030b4415 866
5c7f4665 867 }
030b4415 868
5c7f4665 869}
870
871//_____________________________________________________________________________
a328fff9 872void AliTRDv1::StepManagerFixedStep()
873{
874 //
875 // Slow simulator. Every charged track produces electron cluster as hits
876 // along its path across the drift volume. The step size is fixed in
877 // this version of the step manager.
878 //
879
ce0d6231 880 // PDG code electron
881 const Int_t kPdgElectron = 11;
882
a328fff9 883 Int_t pla = 0;
884 Int_t cha = 0;
885 Int_t sec = 0;
886 Int_t det = 0;
887 Int_t qTot;
888
889 Float_t hits[3];
890 Double_t eDep;
891
892 Bool_t drRegion = kFALSE;
893 Bool_t amRegion = kFALSE;
894
2c8bf4aa 895 TString cIdPath;
896 Char_t cIdSector[3];
897 cIdSector[2] = 0;
898
a328fff9 899 TString cIdCurrent;
900 TString cIdSensDr = "J";
901 TString cIdSensAm = "K";
902 Char_t cIdChamber[3];
2c8bf4aa 903 cIdChamber[2] = 0;
a328fff9 904
030b4415 905 TLorentzVector pos;
906 TLorentzVector mom;
a328fff9 907
908 const Int_t kNplan = AliTRDgeometry::Nplan();
909 const Int_t kNcham = AliTRDgeometry::Ncham();
910 const Int_t kNdetsec = kNplan * kNcham;
911
030b4415 912 const Double_t kBig = 1.0e+12;
a328fff9 913
bc327ce2 914 const Float_t kWion = 23.53; // Ionization energy
a328fff9 915 const Float_t kEkinMinStep = 1.0e-5; // Minimum energy for the step size adjustment
916
917 // Set the maximum step size to a very large number for all
918 // neutral particles and those outside the driftvolume
919 gMC->SetMaxStep(kBig);
920
921 // If not charged track or already stopped or disappeared, just return.
922 if ((!gMC->TrackCharge()) ||
ce0d6231 923 gMC->IsTrackDisappeared()) {
924 return;
925 }
a328fff9 926
927 // Inside a sensitive volume?
928 cIdCurrent = gMC->CurrentVolName();
929
ce0d6231 930 if (cIdSensDr == cIdCurrent[1]) {
931 drRegion = kTRUE;
932 }
933 if (cIdSensAm == cIdCurrent[1]) {
934 amRegion = kTRUE;
935 }
a328fff9 936
030b4415 937 if ((!drRegion) &&
938 (!amRegion)) {
939 return;
940 }
a328fff9 941
942 // The hit coordinates and charge
943 gMC->TrackPosition(pos);
944 hits[0] = pos[0];
945 hits[1] = pos[1];
946 hits[2] = pos[2];
947
2c8bf4aa 948 // The sector number (0 - 17), according to standard coordinate system
949 cIdPath = gGeoManager->GetPath();
950 cIdSector[0] = cIdPath[21];
951 cIdSector[1] = cIdPath[22];
952 sec = atoi(cIdSector);
a328fff9 953
954 // The plane and chamber number
030b4415 955 cIdChamber[0] = cIdCurrent[2];
956 cIdChamber[1] = cIdCurrent[3];
a328fff9 957 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
8a497c18 958 cha = ((Int_t) idChamber / kNplan);
a328fff9 959 pla = ((Int_t) idChamber % kNplan);
e0d47c25 960
030b4415 961 // The detector number
962 det = fGeometry->GetDetector(pla,cha,sec);
963
25ca55ce 964 // 0: InFlight 1:Entering 2:Exiting
030b4415 965 Int_t trkStat = 0;
a328fff9 966
967 // Special hits only in the drift region
ce0d6231 968 if ((drRegion) &&
969 (gMC->IsTrackEntering())) {
a328fff9 970
ce0d6231 971 // Create a track reference at the entrance of each
972 // chamber that contains the momentum components of the particle
973 gMC->TrackMomentum(mom);
974 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
975 trkStat = 1;
a328fff9 976
ce0d6231 977 // Create the hits from TR photons if electron/positron is
978 // entering the drift volume
979 if ((fTR) &&
980 (TMath::Abs(gMC->TrackPid()) == kPdgElectron)) {
030b4415 981 CreateTRhit(det);
982 }
a328fff9 983
984 }
ce0d6231 985 else if ((amRegion) &&
986 (gMC->IsTrackExiting())) {
987
988 // Create a track reference at the exit of each
989 // chamber that contains the momentum components of the particle
990 gMC->TrackMomentum(mom);
991 AddTrackReference(gAlice->GetMCApp()->GetCurrentTrackNumber());
992 trkStat = 2;
993
994 }
a328fff9 995
996 // Calculate the charge according to GEANT Edep
997 // Create a new dEdx hit
998 eDep = TMath::Max(gMC->Edep(),0.0) * 1.0e+09;
999 qTot = (Int_t) (eDep / kWion);
ce0d6231 1000 if ((qTot) ||
1001 (trkStat)) {
1002 AddHit(gAlice->GetMCApp()->GetCurrentTrackNumber()
1003 ,det
1004 ,hits
1005 ,qTot
25ca55ce 1006 ,gMC->TrackTime()*1.0e06
ce0d6231 1007 ,drRegion);
1008 }
a328fff9 1009
1010 // Set Maximum Step Size
1011 // Produce only one hit if Ekin is below cutoff
030b4415 1012 if ((gMC->Etot() - gMC->TrackMass()) < kEkinMinStep) {
1013 return;
1014 }
a328fff9 1015 gMC->SetMaxStep(fStepSize);
1016
1017}
1018
1019//_____________________________________________________________________________
5c7f4665 1020Double_t AliTRDv1::BetheBloch(Double_t bg)
1021{
1022 //
1023 // Parametrization of the Bethe-Bloch-curve
1024 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
1025 //
1026
1027 // This parameters have been adjusted to averaged values from GEANT
f57bb418 1028 const Double_t kP1 = 7.17960e-02;
1029 const Double_t kP2 = 8.54196;
1030 const Double_t kP3 = 1.38065e-06;
1031 const Double_t kP4 = 5.30972;
1032 const Double_t kP5 = 2.83798;
5c7f4665 1033
f73816f5 1034 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
1035 const Double_t kBgMin = 0.8;
1036 const Double_t kBBMax = 6.83298;
f73816f5 1037
1038 if (bg > kBgMin) {
030b4415 1039 Double_t yy = bg / TMath::Sqrt(1.0 + bg*bg);
5c7f4665 1040 Double_t aa = TMath::Power(yy,kP4);
030b4415 1041 Double_t bb = TMath::Power((1.0/bg),kP5);
5c7f4665 1042 bb = TMath::Log(kP3 + bb);
030b4415 1043 return ((kP2 - aa - bb) * kP1 / aa);
5c7f4665 1044 }
f73816f5 1045 else {
1046 return kBBMax;
1047 }
d3f347ff 1048
fe4da5cc 1049}
5c7f4665 1050
1051//_____________________________________________________________________________
c4214bc0 1052Double_t AliTRDv1::BetheBlochGeant(Double_t bg)
a328fff9 1053{
1054 //
1055 // Return dN/dx (number of primary collisions per centimeter)
1056 // for given beta*gamma factor.
1057 //
1058 // Implemented by K.Oyama according to GEANT 3 parametrization shown in
1059 // A.Andronic's webpage: http://www-alice.gsi.de/trd/papers/dedx/dedx.html
1060 // This must be used as a set with IntSpecGeant.
1061 //
1062
030b4415 1063 Int_t i = 0;
a328fff9 1064
030b4415 1065 Double_t arrG[20] = { 1.100000, 1.200000, 1.300000, 1.500000
1066 , 1.800000, 2.000000, 2.500000, 3.000000
1067 , 4.000000, 7.000000, 10.000000, 20.000000
1068 , 40.000000, 70.000000, 100.000000, 300.000000
1069 , 600.000000, 1000.000000, 3000.000000, 10000.000000 };
a328fff9 1070
030b4415 1071 Double_t arrNC[20] = { 75.009056, 45.508083, 35.299252, 27.116327
1072 , 22.734999, 21.411915, 19.934095, 19.449375
1073 , 19.344431, 20.185553, 21.027925, 22.912676
1074 , 24.933352, 26.504053, 27.387468, 29.566597
1075 , 30.353779, 30.787134, 31.129285, 31.157350 };
1076
1077 // Betagamma to gamma
1078 Double_t g = TMath::Sqrt(1.0 + bg*bg);
a328fff9 1079
1080 // Find the index just before the point we need.
030b4415 1081 for (i = 0; i < 18; i++) {
1082 if ((arrG[i] < g) &&
1083 (arrG[i+1] > g)) {
a328fff9 1084 break;
030b4415 1085 }
1086 }
a328fff9 1087
1088 // Simple interpolation.
030b4415 1089 Double_t pp = ((arrNC[i+1] - arrNC[i]) / (arrG[i+1] - arrG[i]))
1090 * (g - arrG[i]) + arrNC[i];
a328fff9 1091
030b4415 1092 return pp;
a328fff9 1093
1094}
1095
1096//_____________________________________________________________________________
5c7f4665 1097Double_t Ermilova(Double_t *x, Double_t *)
1098{
1099 //
1100 // Calculates the delta-ray energy distribution according to Ermilova.
1101 // Logarithmic scale !
1102 //
1103
1104 Double_t energy;
1105 Double_t dpos;
1106 Double_t dnde;
1107
030b4415 1108 Int_t pos1;
1109 Int_t pos2;
5c7f4665 1110
8230f242 1111 const Int_t kNv = 31;
5c7f4665 1112
030b4415 1113 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
1114 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
1115 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
1116 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
1117 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
1118 , 9.4727, 9.9035, 10.3735, 10.5966, 10.8198
1119 , 11.5129 };
1120
1121 Float_t vye[kNv] = { 80.0, 31.0, 23.3, 21.1, 21.0
1122 , 20.9, 20.8, 20.0, 16.0, 11.0
1123 , 8.0, 6.0, 5.2, 4.6, 4.0
1124 , 3.5, 3.0, 1.4, 0.67, 0.44
1125 , 0.3, 0.18, 0.12, 0.08, 0.056
1126 , 0.04, 0.023, 0.015, 0.011, 0.01
1127 , 0.004 };
5c7f4665 1128
1129 energy = x[0];
1130
1131 // Find the position
030b4415 1132 pos1 = 0;
1133 pos2 = 0;
5c7f4665 1134 dpos = 0;
1135 do {
1136 dpos = energy - vxe[pos2++];
1137 }
1138 while (dpos > 0);
1139 pos2--;
030b4415 1140 if (pos2 > kNv) {
1141 pos2 = kNv - 1;
1142 }
5c7f4665 1143 pos1 = pos2 - 1;
1144
1145 // Differentiate between the sampling points
1146 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
1147
1148 return dnde;
1149
1150}
a328fff9 1151
1152//_____________________________________________________________________________
1153Double_t IntSpecGeant(Double_t *x, Double_t *)
1154{
1155 //
1156 // Integrated spectrum from Geant3
1157 //
1158
96efaf83 1159 const Int_t npts = 83;
030b4415 1160 Double_t arre[npts] = { 2.421257, 2.483278, 2.534301, 2.592230
1161 , 2.672067, 2.813299, 3.015059, 3.216819
1162 , 3.418579, 3.620338, 3.868209, 3.920198
1163 , 3.978284, 4.063923, 4.186264, 4.308605
1164 , 4.430946, 4.553288, 4.724261, 4.837736
1165 , 4.999842, 5.161949, 5.324056, 5.486163
1166 , 5.679688, 5.752998, 5.857728, 5.962457
1167 , 6.067185, 6.171914, 6.315653, 6.393674
1168 , 6.471694, 6.539689, 6.597658, 6.655627
1169 , 6.710957, 6.763648, 6.816338, 6.876198
1170 , 6.943227, 7.010257, 7.106285, 7.252151
1171 , 7.460531, 7.668911, 7.877290, 8.085670
1172 , 8.302979, 8.353585, 8.413120, 8.483500
1173 , 8.541030, 8.592857, 8.668865, 8.820485
1174 , 9.037086, 9.253686, 9.470286, 9.686887
1175 , 9.930838, 9.994655, 10.085822, 10.176990
1176 , 10.268158, 10.359325, 10.503614, 10.627565
1177 , 10.804637, 10.981709, 11.158781, 11.335854
1178 , 11.593397, 11.781165, 12.049404, 12.317644
1179 , 12.585884, 12.854123, 14.278421, 16.975889
1180 , 20.829416, 24.682943, 28.536469 };
1181
1182 Double_t arrdnde[npts] = { 10.960000, 10.960000, 10.359500, 9.811340
1183 , 9.1601500, 8.206670, 6.919630, 5.655430
1184 , 4.6221300, 3.777610, 3.019560, 2.591950
1185 , 2.5414600, 2.712920, 3.327460, 4.928240
1186 , 7.6185300, 10.966700, 12.225800, 8.094750
1187 , 3.3586900, 1.553650, 1.209600, 1.263840
1188 , 1.3241100, 1.312140, 1.255130, 1.165770
1189 , 1.0594500, 0.945450, 0.813231, 0.699837
1190 , 0.6235580, 2.260990, 2.968350, 2.240320
1191 , 1.7988300, 1.553300, 1.432070, 1.535520
1192 , 1.4429900, 1.247990, 1.050750, 0.829549
1193 , 0.5900280, 0.395897, 0.268741, 0.185320
1194 , 0.1292120, 0.103545, 0.0949525, 0.101535
1195 , 0.1276380, 0.134216, 0.123816, 0.104557
1196 , 0.0751843, 0.0521745, 0.0373546, 0.0275391
1197 , 0.0204713, 0.0169234, 0.0154552, 0.0139194
1198 , 0.0125592, 0.0113638, 0.0107354, 0.0102137
1199 , 0.00845984, 0.00683338, 0.00556836, 0.00456874
1200 , 0.0036227, 0.00285991, 0.00226664, 0.00172234
1201 , 0.00131226, 0.00100284, 0.000465492, 7.26607e-05
1202 , 3.63304e-06, 0.0000000, 0.0000000 };
1203
1204 Int_t i;
a328fff9 1205 Double_t energy = x[0];
a328fff9 1206
030b4415 1207 for (i = 0; i < npts; i++) {
1208 if (energy < arre[i]) {
1209 break;
1210 }
1211 }
a328fff9 1212
030b4415 1213 if (i == 0) {
1214 AliErrorGeneral("AliTRDv1::IntSpecGeant","Given energy value is too small or zero");
1215 }
a328fff9 1216
f57bb418 1217 return arrdnde[i];
a328fff9 1218
1219}