Changes in StepManager to speed simulation
[u/mrichter/AliRoot.git] / TRD / AliTRDv1.cxx
CommitLineData
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
16/*
17$Log$
a3c76cdc 18Revision 1.26 2000/11/30 17:38:08 cblume
19Changes to get in line with new STEER and EVGEN
20
1819f4bb 21Revision 1.25 2000/11/15 14:30:16 cblume
22Fixed bug in calculating detector no. of extra hit
23
990e4068 24Revision 1.24 2000/11/10 14:58:36 cblume
25Introduce additional hit with amplitude 0 at the chamber borders
26
769257f4 27Revision 1.23 2000/11/01 14:53:21 cblume
28Merge with TRD-develop
29
793ff80c 30Revision 1.17.2.5 2000/10/15 23:40:01 cblume
31Remove AliTRDconst
32
33Revision 1.17.2.4 2000/10/06 16:49:46 cblume
34Made Getters const
35
36Revision 1.17.2.3 2000/10/04 16:34:58 cblume
37Replace include files by forward declarations
38
39Revision 1.17.2.2 2000/09/18 13:50:17 cblume
40Include TR photon generation and adapt to new AliTRDhit
41
42Revision 1.22 2000/06/27 13:08:50 cblume
43Changed to Copy(TObject &A) to appease the HP-compiler
44
43da34c0 45Revision 1.21 2000/06/09 11:10:07 cblume
46Compiler warnings and coding conventions, next round
47
dd9a6ee3 48Revision 1.20 2000/06/08 18:32:58 cblume
49Make code compliant to coding conventions
50
8230f242 51Revision 1.19 2000/06/07 16:27:32 cblume
52Try to remove compiler warnings on Sun and HP
53
9d0b222b 54Revision 1.18 2000/05/08 16:17:27 cblume
55Merge TRD-develop
56
6f1e466d 57Revision 1.17.2.1 2000/05/08 14:59:16 cblume
58Made inline function non-virtual. Bug fix in setting sensitive chamber
59
60Revision 1.17 2000/02/28 19:10:26 cblume
61Include the new TRD classes
62
851d3db9 63Revision 1.16.4.1 2000/02/28 18:04:35 cblume
64Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
65
66Revision 1.16 1999/11/05 22:50:28 fca
67Do not use Atan, removed from ROOT too
68
90f8d287 69Revision 1.15 1999/11/02 17:20:19 fca
70initialise nbytes before using it
71
036da493 72Revision 1.14 1999/11/02 17:15:54 fca
73Correct ansi scoping not accepted by HP compilers
74
0549c011 75Revision 1.13 1999/11/02 17:14:51 fca
76Correct ansi scoping not accepted by HP compilers
77
9c767df4 78Revision 1.12 1999/11/02 16:35:56 fca
79New version of TRD introduced
80
5c7f4665 81Revision 1.11 1999/11/01 20:41:51 fca
82Added protections against using the wrong version of FRAME
83
ab76897d 84Revision 1.10 1999/09/29 09:24:35 fca
85Introduction of the Copyright and cvs Log
86
4c039060 87*/
88
fe4da5cc 89///////////////////////////////////////////////////////////////////////////////
90// //
769257f4 91// Transition Radiation Detector version 1 -- slow simulator //
fe4da5cc 92// //
93//Begin_Html
94/*
5c7f4665 95<img src="picts/AliTRDfullClass.gif">
fe4da5cc 96*/
97//End_Html
98// //
99// //
100///////////////////////////////////////////////////////////////////////////////
101
769257f4 102#include <stdlib.h>
103
fe4da5cc 104#include <TMath.h>
fe4da5cc 105#include <TVector.h>
5c7f4665 106#include <TRandom.h>
793ff80c 107#include <TF1.h>
1819f4bb 108#include <TLorentzVector.h>
fe4da5cc 109
fe4da5cc 110#include "AliRun.h"
fe4da5cc 111#include "AliMC.h"
d3f347ff 112#include "AliConst.h"
5c7f4665 113
851d3db9 114#include "AliTRDv1.h"
793ff80c 115#include "AliTRDhit.h"
851d3db9 116#include "AliTRDmatrix.h"
117#include "AliTRDgeometry.h"
793ff80c 118#include "AliTRDsim.h"
851d3db9 119
fe4da5cc 120ClassImp(AliTRDv1)
8230f242 121
122//_____________________________________________________________________________
123AliTRDv1::AliTRDv1():AliTRD()
124{
125 //
126 // Default constructor
127 //
128
129 fIdSens = 0;
130
131 fIdChamber1 = 0;
132 fIdChamber2 = 0;
133 fIdChamber3 = 0;
134
135 fSensSelect = 0;
136 fSensPlane = -1;
137 fSensChamber = -1;
138 fSensSector = -1;
139 fSensSectorRange = 0;
140
141 fDeltaE = NULL;
793ff80c 142 fTR = NULL;
8230f242 143
144}
145
fe4da5cc 146//_____________________________________________________________________________
147AliTRDv1::AliTRDv1(const char *name, const char *title)
148 :AliTRD(name, title)
149{
150 //
851d3db9 151 // Standard constructor for Transition Radiation Detector version 1
fe4da5cc 152 //
82bbf98a 153
9d0b222b 154 fIdSens = 0;
82bbf98a 155
9d0b222b 156 fIdChamber1 = 0;
157 fIdChamber2 = 0;
158 fIdChamber3 = 0;
5c7f4665 159
9d0b222b 160 fSensSelect = 0;
161 fSensPlane = -1;
162 fSensChamber = -1;
163 fSensSector = -1;
8230f242 164 fSensSectorRange = 0;
5c7f4665 165
9d0b222b 166 fDeltaE = NULL;
793ff80c 167 fTR = NULL;
5c7f4665 168
169 SetBufferSize(128000);
170
171}
172
173//_____________________________________________________________________________
dd9a6ee3 174AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
8230f242 175{
176 //
177 // Copy constructor
178 //
179
dd9a6ee3 180 ((AliTRDv1 &) trd).Copy(*this);
8230f242 181
182}
183
184//_____________________________________________________________________________
5c7f4665 185AliTRDv1::~AliTRDv1()
186{
dd9a6ee3 187 //
188 // AliTRDv1 destructor
189 //
82bbf98a 190
5c7f4665 191 if (fDeltaE) delete fDeltaE;
793ff80c 192 if (fTR) delete fTR;
82bbf98a 193
fe4da5cc 194}
195
dd9a6ee3 196//_____________________________________________________________________________
197AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
198{
199 //
200 // Assignment operator
201 //
202
203 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
204 return *this;
205
206}
8230f242 207
208//_____________________________________________________________________________
43da34c0 209void AliTRDv1::Copy(TObject &trd)
8230f242 210{
211 //
212 // Copy function
213 //
214
43da34c0 215 ((AliTRDv1 &) trd).fIdSens = fIdSens;
8230f242 216
43da34c0 217 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
218 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
219 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
8230f242 220
43da34c0 221 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
222 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
223 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
224 ((AliTRDv1 &) trd).fSensSector = fSensSector;
225 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
8230f242 226
793ff80c 227 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
228 fTR->Copy(*((AliTRDv1 &) trd).fTR);
8230f242 229
230}
231
fe4da5cc 232//_____________________________________________________________________________
233void AliTRDv1::CreateGeometry()
234{
235 //
851d3db9 236 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
5c7f4665 237 // This version covers the full azimuth.
d3f347ff 238 //
239
82bbf98a 240 // Check that FRAME is there otherwise we have no place where to put the TRD
8230f242 241 AliModule* frame = gAlice->GetModule("FRAME");
242 if (!frame) return;
d3f347ff 243
82bbf98a 244 // Define the chambers
245 AliTRD::CreateGeometry();
d3f347ff 246
fe4da5cc 247}
248
249//_____________________________________________________________________________
250void AliTRDv1::CreateMaterials()
251{
252 //
851d3db9 253 // Create materials for the Transition Radiation Detector version 1
fe4da5cc 254 //
82bbf98a 255
d3f347ff 256 AliTRD::CreateMaterials();
82bbf98a 257
fe4da5cc 258}
259
260//_____________________________________________________________________________
793ff80c 261void AliTRDv1::CreateTRhit(Int_t det)
262{
263 //
264 // Creates an electron cluster from a TR photon.
265 // The photon is assumed to be created a the end of the radiator. The
266 // distance after which it deposits its energy takes into account the
267 // absorbtion of the entrance window and of the gas mixture in drift
268 // volume.
269 //
270
271 // PDG code electron
272 const Int_t kPdgElectron = 11;
273
274 // Ionization energy
275 const Float_t kWion = 22.04;
276
277 // Maximum number of TR photons per track
278 const Int_t kNTR = 50;
279
280 TLorentzVector mom, pos;
281 TClonesArray &lhits = *fHits;
282
283 // Create TR only for electrons
284 Int_t iPdg = gMC->TrackPid();
285 if (TMath::Abs(iPdg) != kPdgElectron) return;
286
287 // Create TR at the entrance of the chamber
288 if (gMC->IsTrackEntering()) {
289
290 Float_t eTR[kNTR];
291 Int_t nTR;
292
293 // Create TR photons
294 gMC->TrackMomentum(mom);
295 Float_t pTot = mom.Rho();
296 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
297 if (nTR > kNTR) {
298 printf("AliTRDv1::CreateTRhit -- ");
299 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
300 exit(1);
301 }
302
303 // Loop through the TR photons
304 for (Int_t iTR = 0; iTR < nTR; iTR++) {
305
306 Float_t energyMeV = eTR[iTR] * 0.001;
307 Float_t energyeV = eTR[iTR] * 1000.0;
308 Float_t absLength = 0;
309 Float_t sigma = 0;
310
311 // Take the absorbtion in the entrance window into account
312 Double_t muMy = fTR->GetMuMy(energyMeV);
313 sigma = muMy * fFoilDensity;
314 absLength = gRandom->Exp(sigma);
315 if (absLength < AliTRDgeometry::MyThick()) continue;
316
317 // The absorbtion cross sections in the drift gas
318 if (fGasMix == 1) {
319 // Gas-mixture (Xe/CO2)
320 Double_t muXe = fTR->GetMuXe(energyMeV);
321 Double_t muCO = fTR->GetMuCO(energyMeV);
322 sigma = (0.90 * muXe + 0.10 * muCO) * fGasDensity;
323 }
324 else {
325 // Gas-mixture (Xe/Isobutane)
326 Double_t muXe = fTR->GetMuXe(energyMeV);
327 Double_t muBu = fTR->GetMuBu(energyMeV);
328 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
329 }
330
331 // The distance after which the energy of the TR photon
332 // is deposited.
333 absLength = gRandom->Exp(sigma);
334 if (absLength > AliTRDgeometry::DrThick()) continue;
335
336 // The position of the absorbtion
337 Float_t posHit[3];
338 gMC->TrackPosition(pos);
339 posHit[0] = pos[0] + mom[0] / pTot * absLength;
340 posHit[1] = pos[1] + mom[1] / pTot * absLength;
341 posHit[2] = pos[2] + mom[2] / pTot * absLength;
342
343 // Create the charge
344 Int_t q = ((Int_t) (energyeV / kWion));
345
346 // Add the hit to the array. TR photon hits are marked
347 // by negative charge
348 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack()
349 ,det,posHit,-q);
350
351 }
352
353 }
354
355}
356
357//_____________________________________________________________________________
5c7f4665 358void AliTRDv1::Init()
359{
360 //
361 // Initialise Transition Radiation Detector after geometry has been built.
5c7f4665 362 //
363
364 AliTRD::Init();
365
851d3db9 366 printf(" Slow simulator\n\n");
367 if (fSensSelect) {
368 if (fSensPlane >= 0)
369 printf(" Only plane %d is sensitive\n",fSensPlane);
370 if (fSensChamber >= 0)
371 printf(" Only chamber %d is sensitive\n",fSensChamber);
9d0b222b 372 if (fSensSector >= 0) {
373 Int_t sens1 = fSensSector;
374 Int_t sens2 = fSensSector + fSensSectorRange;
793ff80c 375 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
376 * AliTRDgeometry::Nsect();
9d0b222b 377 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
378 }
851d3db9 379 }
793ff80c 380 if (fTR)
381 printf(" TR simulation on\n");
382 else
383 printf(" TR simulation off\n");
851d3db9 384 printf("\n");
5c7f4665 385
386 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
387 const Float_t kPoti = 12.1;
388 // Maximum energy (50 keV);
389 const Float_t kEend = 50000.0;
390 // Ermilova distribution for the delta-ray spectrum
8230f242 391 Float_t poti = TMath::Log(kPoti);
392 Float_t eEnd = TMath::Log(kEend);
793ff80c 393 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
5c7f4665 394
395 // Identifier of the sensitive volume (drift region)
396 fIdSens = gMC->VolId("UL05");
82bbf98a 397
398 // Identifier of the TRD-driftchambers
399 fIdChamber1 = gMC->VolId("UCIO");
400 fIdChamber2 = gMC->VolId("UCIM");
401 fIdChamber3 = gMC->VolId("UCII");
402
5c7f4665 403 for (Int_t i = 0; i < 80; i++) printf("*");
404 printf("\n");
405
fe4da5cc 406}
407
408//_____________________________________________________________________________
793ff80c 409AliTRDsim *AliTRDv1::CreateTR()
410{
411 //
412 // Enables the simulation of TR
413 //
414
415 fTR = new AliTRDsim();
416 return fTR;
417
418}
419
420//_____________________________________________________________________________
5c7f4665 421void AliTRDv1::SetSensPlane(Int_t iplane)
422{
423 //
851d3db9 424 // Defines the hit-sensitive plane (0-5)
5c7f4665 425 //
82bbf98a 426
851d3db9 427 if ((iplane < 0) || (iplane > 5)) {
5c7f4665 428 printf("Wrong input value: %d\n",iplane);
429 printf("Use standard setting\n");
851d3db9 430 fSensPlane = -1;
431 fSensSelect = 0;
5c7f4665 432 return;
433 }
82bbf98a 434
5c7f4665 435 fSensSelect = 1;
436 fSensPlane = iplane;
82bbf98a 437
5c7f4665 438}
439
440//_____________________________________________________________________________
441void AliTRDv1::SetSensChamber(Int_t ichamber)
442{
443 //
851d3db9 444 // Defines the hit-sensitive chamber (0-4)
5c7f4665 445 //
446
851d3db9 447 if ((ichamber < 0) || (ichamber > 4)) {
5c7f4665 448 printf("Wrong input value: %d\n",ichamber);
449 printf("Use standard setting\n");
851d3db9 450 fSensChamber = -1;
451 fSensSelect = 0;
5c7f4665 452 return;
453 }
454
455 fSensSelect = 1;
456 fSensChamber = ichamber;
457
458}
459
460//_____________________________________________________________________________
461void AliTRDv1::SetSensSector(Int_t isector)
462{
463 //
851d3db9 464 // Defines the hit-sensitive sector (0-17)
5c7f4665 465 //
466
9d0b222b 467 SetSensSector(isector,1);
468
469}
470
471//_____________________________________________________________________________
472void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
473{
474 //
475 // Defines a range of hit-sensitive sectors. The range is defined by
476 // <isector> (0-17) as the starting point and <nsector> as the number
477 // of sectors to be included.
478 //
479
851d3db9 480 if ((isector < 0) || (isector > 17)) {
9d0b222b 481 printf("Wrong input value <isector>: %d\n",isector);
5c7f4665 482 printf("Use standard setting\n");
9d0b222b 483 fSensSector = -1;
484 fSensSectorRange = 0;
485 fSensSelect = 0;
5c7f4665 486 return;
487 }
488
9d0b222b 489 if ((nsector < 1) || (nsector > 18)) {
490 printf("Wrong input value <nsector>: %d\n",nsector);
491 printf("Use standard setting\n");
492 fSensSector = -1;
493 fSensSectorRange = 0;
494 fSensSelect = 0;
495 return;
496 }
497
498 fSensSelect = 1;
499 fSensSector = isector;
500 fSensSectorRange = nsector;
5c7f4665 501
502}
503
504//_____________________________________________________________________________
505void AliTRDv1::StepManager()
506{
507 //
5c7f4665 508 // Slow simulator. Every charged track produces electron cluster as hits
509 // along its path across the drift volume. The step size is set acording
510 // to Bethe-Bloch. The energy distribution of the delta electrons follows
511 // a spectrum taken from Ermilova et al.
512 //
513
514 Int_t iIdSens, icSens;
515 Int_t iIdSpace, icSpace;
516 Int_t iIdChamber, icChamber;
851d3db9 517 Int_t pla = 0;
518 Int_t cha = 0;
519 Int_t sec = 0;
793ff80c 520 Int_t det = 0;
851d3db9 521 Int_t iPdg;
793ff80c 522 Int_t qTot;
5c7f4665 523
793ff80c 524 Float_t hits[3];
990e4068 525 Float_t moms[3];
5c7f4665 526 Float_t random[1];
527 Float_t charge;
528 Float_t aMass;
529
530 Double_t pTot;
5c7f4665 531 Double_t eDelta;
532 Double_t betaGamma, pp;
533
534 TLorentzVector pos, mom;
82bbf98a 535 TClonesArray &lhits = *fHits;
536
851d3db9 537 const Double_t kBig = 1.0E+12;
5c7f4665 538
539 // Ionization energy
a3c76cdc 540 const Float_t kWion = 22.04;
541 // Maximum momentum for e+ e- g
542 const Float_t kPTotMaxEl = 0.002;
543 // Minimum momentum for the step size adjustment
544 const Float_t kPTotMinStep = 1.0e-5;
5c7f4665 545 // Plateau value of the energy-loss for electron in xenon
546 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
547 //const Double_t kPlateau = 1.70;
548 // the averaged value (26/3/99)
a3c76cdc 549 const Float_t kPlateau = 1.55;
5c7f4665 550 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
a3c76cdc 551 const Float_t kPrim = 48.0;
5c7f4665 552 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
a3c76cdc 553 const Float_t kPoti = 12.1;
851d3db9 554
555 // PDG code electron
8230f242 556 const Int_t kPdgElectron = 11;
5c7f4665 557
558 // Set the maximum step size to a very large number for all
559 // neutral particles and those outside the driftvolume
560 gMC->SetMaxStep(kBig);
561
769257f4 562 // Create some special hits with amplitude 0 at the entrance and
563 // exit of each chamber that contain the momentum components of the particle
564 if (gMC->TrackCharge() &&
565 (gMC->IsTrackEntering() || gMC->IsTrackExiting())) {
566
567 // Inside a sensitive volume?
568 iIdSens = gMC->CurrentVolID(icSens);
569 if (iIdSens == fIdSens) {
570
571 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
572 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
573
574 // The hit coordinates
575 gMC->TrackPosition(pos);
990e4068 576 hits[0] = pos[0];
577 hits[1] = pos[1];
578 hits[2] = pos[2];
769257f4 579
580 // The track momentum
581 gMC->TrackMomentum(mom);
990e4068 582 moms[0] = mom[0];
583 moms[1] = mom[1];
584 moms[2] = mom[2];
769257f4 585
586 // The sector number (0 - 17)
587 // The numbering goes clockwise and starts at y = 0
588 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
589 if (phi < 90.)
590 phi = phi + 270.;
591 else
592 phi = phi - 90.;
593 sec = ((Int_t) (phi / 20));
594
595 // The chamber number
596 // 0: outer left
597 // 1: middle left
598 // 2: inner
599 // 3: middle right
600 // 4: outer right
601 if (iIdChamber == fIdChamber1)
602 cha = (hits[2] < 0 ? 0 : 4);
603 else if (iIdChamber == fIdChamber2)
604 cha = (hits[2] < 0 ? 1 : 3);
605 else if (iIdChamber == fIdChamber3)
606 cha = 2;
607
608 // The plane number
609 // The numbering starts at the innermost plane
610 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
611
612 // Check on selected volumes
613 Int_t addthishit = 1;
614 if (fSensSelect) {
615 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
616 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
617 if (fSensSector >= 0) {
618 Int_t sens1 = fSensSector;
619 Int_t sens2 = fSensSector + fSensSectorRange;
620 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
621 * AliTRDgeometry::Nsect();
622 if (sens1 < sens2) {
623 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
624 }
625 else {
626 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
627 }
628 }
629 }
630
631 // Add this hit
632 if (addthishit) {
633 det = fGeometry->GetDetector(pla,cha,sec);
634 new(lhits[fNhits++]) AliTRDhit(fIshunt
635 ,gAlice->CurrentTrack()
636 ,det
990e4068 637 ,moms
769257f4 638 ,0);
639 }
640
641 }
642
643 }
644
5c7f4665 645 // Use only charged tracks
646 if (( gMC->TrackCharge() ) &&
647 (!gMC->IsTrackStop() ) &&
648 (!gMC->IsTrackDisappeared())) {
fe4da5cc 649
5c7f4665 650 // Inside a sensitive volume?
82bbf98a 651 iIdSens = gMC->CurrentVolID(icSens);
652 if (iIdSens == fIdSens) {
653
82bbf98a 654 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
655 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
fe4da5cc 656
5c7f4665 657 // Calculate the energy of the delta-electrons
658 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
659 eDelta = TMath::Max(eDelta,0.0);
660
661 // The number of secondary electrons created
793ff80c 662 qTot = ((Int_t) (eDelta / kWion) + 1);
5c7f4665 663
664 // The hit coordinates and charge
665 gMC->TrackPosition(pos);
666 hits[0] = pos[0];
667 hits[1] = pos[1];
668 hits[2] = pos[2];
5c7f4665 669
851d3db9 670 // The sector number (0 - 17)
671 // The numbering goes clockwise and starts at y = 0
672 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
673 if (phi < 90.)
674 phi = phi + 270.;
675 else
676 phi = phi - 90.;
677 sec = ((Int_t) (phi / 20));
82bbf98a 678
d3f347ff 679 // The chamber number
851d3db9 680 // 0: outer left
681 // 1: middle left
682 // 2: inner
683 // 3: middle right
684 // 4: outer right
82bbf98a 685 if (iIdChamber == fIdChamber1)
851d3db9 686 cha = (hits[2] < 0 ? 0 : 4);
82bbf98a 687 else if (iIdChamber == fIdChamber2)
851d3db9 688 cha = (hits[2] < 0 ? 1 : 3);
82bbf98a 689 else if (iIdChamber == fIdChamber3)
851d3db9 690 cha = 2;
82bbf98a 691
fe4da5cc 692 // The plane number
851d3db9 693 // The numbering starts at the innermost plane
694 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
82bbf98a 695
5c7f4665 696 // Check on selected volumes
697 Int_t addthishit = 1;
698 if (fSensSelect) {
6f1e466d 699 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
700 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
9d0b222b 701 if (fSensSector >= 0) {
702 Int_t sens1 = fSensSector;
703 Int_t sens2 = fSensSector + fSensSectorRange;
793ff80c 704 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
705 * AliTRDgeometry::Nsect();
9d0b222b 706 if (sens1 < sens2) {
707 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
708 }
709 else {
710 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
711 }
712 }
5c7f4665 713 }
714
715 // Add this hit
716 if (addthishit) {
717
793ff80c 718 det = fGeometry->GetDetector(pla,cha,sec);
719
720 // Create the electron cluster from TR photons
721 if (fTR) CreateTRhit(det);
722
851d3db9 723 new(lhits[fNhits++]) AliTRDhit(fIshunt
724 ,gAlice->CurrentTrack()
9d0b222b 725 ,det
793ff80c 726 ,hits
727 ,qTot);
5c7f4665 728
729 // The energy loss according to Bethe Bloch
730 gMC->TrackMomentum(mom);
731 pTot = mom.Rho();
851d3db9 732 iPdg = TMath::Abs(gMC->TrackPid());
8230f242 733 if ( (iPdg != kPdgElectron) ||
a3c76cdc 734 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
5c7f4665 735 aMass = gMC->TrackMass();
736 betaGamma = pTot / aMass;
737 pp = kPrim * BetheBloch(betaGamma);
738 // Take charge > 1 into account
739 charge = gMC->TrackCharge();
740 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
741 }
742 // Electrons above 20 Mev/c are at the plateau
743 else {
744 pp = kPrim * kPlateau;
745 }
746
747 // Calculate the maximum step size for the next tracking step
a3c76cdc 748 // introduce a lower momentum cut
749 //if ((pp > 0) && (pTot > kPTotMinStep)) {
5c7f4665 750 if (pp > 0) {
751 do
752 gMC->Rndm(random,1);
753 while ((random[0] == 1.) || (random[0] == 0.));
754 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
755 }
756
757 }
758 else {
759 // set step size to maximal value
760 gMC->SetMaxStep(kBig);
761 }
d3f347ff 762
763 }
764
5c7f4665 765 }
766
767}
768
769//_____________________________________________________________________________
770Double_t AliTRDv1::BetheBloch(Double_t bg)
771{
772 //
773 // Parametrization of the Bethe-Bloch-curve
774 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
775 //
776
777 // This parameters have been adjusted to averaged values from GEANT
778 const Double_t kP1 = 7.17960e-02;
779 const Double_t kP2 = 8.54196;
780 const Double_t kP3 = 1.38065e-06;
781 const Double_t kP4 = 5.30972;
782 const Double_t kP5 = 2.83798;
783
784 // This parameters have been adjusted to Xe-data found in:
785 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
786 //const Double_t kP1 = 0.76176E-1;
787 //const Double_t kP2 = 10.632;
788 //const Double_t kP3 = 3.17983E-6;
789 //const Double_t kP4 = 1.8631;
790 //const Double_t kP5 = 1.9479;
791
792 if (bg > 0) {
793 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
794 Double_t aa = TMath::Power(yy,kP4);
795 Double_t bb = TMath::Power((1./bg),kP5);
796 bb = TMath::Log(kP3 + bb);
797 return ((kP2 - aa - bb)*kP1 / aa);
798 }
799 else
800 return 0;
d3f347ff 801
fe4da5cc 802}
5c7f4665 803
804//_____________________________________________________________________________
805Double_t Ermilova(Double_t *x, Double_t *)
806{
807 //
808 // Calculates the delta-ray energy distribution according to Ermilova.
809 // Logarithmic scale !
810 //
811
812 Double_t energy;
813 Double_t dpos;
814 Double_t dnde;
815
816 Int_t pos1, pos2;
817
8230f242 818 const Int_t kNv = 31;
5c7f4665 819
8230f242 820 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
821 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
822 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
823 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
824 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
825 , 9.4727, 9.9035,10.3735,10.5966,10.8198
826 ,11.5129 };
5c7f4665 827
8230f242 828 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
829 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
830 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
831 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
832 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
833 , 0.04 , 0.023, 0.015, 0.011, 0.01
834 , 0.004 };
5c7f4665 835
836 energy = x[0];
837
838 // Find the position
839 pos1 = pos2 = 0;
840 dpos = 0;
841 do {
842 dpos = energy - vxe[pos2++];
843 }
844 while (dpos > 0);
845 pos2--;
8230f242 846 if (pos2 > kNv) pos2 = kNv;
5c7f4665 847 pos1 = pos2 - 1;
848
849 // Differentiate between the sampling points
850 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
851
852 return dnde;
853
854}