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Geometry update, compressed hit structure
[u/mrichter/AliRoot.git] / TRD / AliTRDdigitizer.cxx
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f7336fa3 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$Log$
a1c3aded 18Revision 1.29 2001/11/14 19:44:25 hristov
19Numeric const casted (Alpha)
20
20c69486 21Revision 1.28 2001/11/14 16:35:58 cblume
22Inherits now from AliDetector
23
85cbec76 24Revision 1.27 2001/11/14 10:50:45 cblume
25Changes in digits IO. Add merging of summable digits
26
abaf1f1d 27Revision 1.26 2001/11/06 17:19:41 cblume
28Add detailed geometry and simple simulator
29
16bf9884 30Revision 1.25 2001/06/27 09:54:44 cblume
31Moved fField initialization to InitDetector()
32
88fd7ccb 33Revision 1.24 2001/05/21 16:45:47 hristov
34Last minute changes (C.Blume)
35
db30bf0f 36Revision 1.23 2001/05/07 08:04:48 cblume
37New TRF and PRF. Speedup of the code. Digits from amplification region included
38
872a7aba 39Revision 1.22 2001/03/30 14:40:14 cblume
40Update of the digitization parameter
41
a3c76cdc 42Revision 1.21 2001/03/13 09:30:35 cblume
43Update of digitization. Moved digit branch definition to AliTRD
44
6244debe 45Revision 1.20 2001/02/25 20:19:00 hristov
46Minor correction: loop variable declared only once for HP, Sun
47
c3a4830f 48Revision 1.19 2001/02/14 18:22:26 cblume
49Change in the geometry of the padplane
50
71d9fa7b 51Revision 1.18 2001/01/26 19:56:57 hristov
52Major upgrade of AliRoot code
53
2ab0c725 54Revision 1.17 2000/12/08 12:53:27 cblume
55Change in Copy() function for HP-compiler
56
1948ba0c 57Revision 1.16 2000/12/07 12:20:46 cblume
58Go back to array compression. Use sampled PRF to speed up digitization
59
e153aaf6 60Revision 1.15 2000/11/23 14:34:08 cblume
61Fixed bug in expansion routine of arrays (initialize buffers properly)
62
259b9e4b 63Revision 1.14 2000/11/20 08:54:44 cblume
64Switch off compression as default
65
c1e4b257 66Revision 1.13 2000/11/10 14:57:52 cblume
67Changes in the geometry constants for the DEC compiler
68
dd56b762 69Revision 1.12 2000/11/01 14:53:20 cblume
70Merge with TRD-develop
71
793ff80c 72Revision 1.1.4.9 2000/10/26 17:00:22 cblume
73Fixed bug in CheckDetector()
74
75Revision 1.1.4.8 2000/10/23 13:41:35 cblume
76Added protection against Log(0) in the gas gain calulation
77
78Revision 1.1.4.7 2000/10/17 02:27:34 cblume
79Get rid of global constants
80
81Revision 1.1.4.6 2000/10/16 01:16:53 cblume
82Changed timebin 0 to be the one closest to the readout
83
84Revision 1.1.4.5 2000/10/15 23:34:29 cblume
85Faster version of the digitizer
86
87Revision 1.1.4.4 2000/10/06 16:49:46 cblume
88Made Getters const
89
90Revision 1.1.4.3 2000/10/04 16:34:58 cblume
91Replace include files by forward declarations
92
93Revision 1.1.4.2 2000/09/22 14:41:10 cblume
94Bug fix in PRF. Included time response. New structure
95
eda4336d 96Revision 1.10 2000/10/05 07:27:53 cblume
97Changes in the header-files by FCA
98
6798b56e 99Revision 1.9 2000/10/02 21:28:19 fca
100Removal of useless dependecies via forward declarations
101
94de3818 102Revision 1.8 2000/06/09 11:10:07 cblume
103Compiler warnings and coding conventions, next round
104
dd9a6ee3 105Revision 1.7 2000/06/08 18:32:58 cblume
106Make code compliant to coding conventions
107
8230f242 108Revision 1.6 2000/06/07 16:27:32 cblume
109Try to remove compiler warnings on Sun and HP
110
9d0b222b 111Revision 1.5 2000/05/09 16:38:57 cblume
112Removed PadResponse(). Merge problem
113
f0a7bf65 114Revision 1.4 2000/05/08 15:53:45 cblume
115Resolved merge conflict
116
da581aea 117Revision 1.3 2000/04/28 14:49:27 cblume
118Only one declaration of iDict in MakeDigits()
119
120Revision 1.1.4.1 2000/05/08 14:42:04 cblume
121Introduced AliTRDdigitsManager
28329a48 122
1befd3b2 123Revision 1.1 2000/02/28 19:00:13 cblume
124Add new TRD classes
125
f7336fa3 126*/
127
128///////////////////////////////////////////////////////////////////////////////
129// //
130// Creates and handles digits from TRD hits //
abaf1f1d 131// Author: C. Blume (C.Blume@gsi.de) //
f7336fa3 132// //
133// The following effects are included: //
134// - Diffusion //
135// - ExB effects //
136// - Gas gain including fluctuations //
137// - Pad-response (simple Gaussian approximation) //
abaf1f1d 138// - Time-response //
f7336fa3 139// - Electronics noise //
140// - Electronics gain //
141// - Digitization //
142// - ADC threshold //
143// The corresponding parameter can be adjusted via the various //
144// Set-functions. If these parameters are not explicitly set, default //
145// values are used (see Init-function). //
abaf1f1d 146// As an example on how to use this class to produce digits from hits //
147// have a look at the macro hits2digits.C //
148// The production of summable digits is demonstrated in hits2sdigits.C //
149// and the subsequent conversion of the s-digits into normal digits is //
150// explained in sdigits2digits.C. //
f7336fa3 151// //
152///////////////////////////////////////////////////////////////////////////////
153
6798b56e 154#include <stdlib.h>
155
f7336fa3 156#include <TMath.h>
157#include <TVector.h>
158#include <TRandom.h>
94de3818 159#include <TROOT.h>
160#include <TTree.h>
793ff80c 161#include <TFile.h>
162#include <TF1.h>
abaf1f1d 163#include <TList.h>
85cbec76 164#include <TTask.h>
793ff80c 165
166#include "AliRun.h"
db30bf0f 167#include "AliMagF.h"
85cbec76 168#include "AliRunDigitizer.h"
f7336fa3 169
170#include "AliTRD.h"
793ff80c 171#include "AliTRDhit.h"
f7336fa3 172#include "AliTRDdigitizer.h"
da581aea 173#include "AliTRDdataArrayI.h"
174#include "AliTRDdataArrayF.h"
793ff80c 175#include "AliTRDsegmentArray.h"
da581aea 176#include "AliTRDdigitsManager.h"
793ff80c 177#include "AliTRDgeometry.h"
f7336fa3 178
179ClassImp(AliTRDdigitizer)
180
181//_____________________________________________________________________________
85cbec76 182AliTRDdigitizer::AliTRDdigitizer()
f7336fa3 183{
184 //
185 // AliTRDdigitizer default constructor
186 //
187
abaf1f1d 188 fInputFile = NULL;
189 fDigitsManager = NULL;
190 fSDigitsManagerList = NULL;
191 fSDigitsManager = NULL;
192 fTRD = NULL;
193 fGeo = NULL;
194 fPRFsmp = NULL;
195 fTRFsmp = NULL;
196
197 fEvent = 0;
198 fGasGain = 0.0;
199 fNoise = 0.0;
200 fChipGain = 0.0;
201 fADCoutRange = 0.0;
202 fADCinRange = 0.0;
203 fADCthreshold = 0;
204 fDiffusionOn = 0;
205 fDiffusionT = 0.0;
206 fDiffusionL = 0.0;
207 fElAttachOn = 0;
208 fElAttachProp = 0.0;
209 fExBOn = 0;
210 fOmegaTau = 0.0;
211 fPRFOn = 0;
212 fTRFOn = 0;
213 fDriftVelocity = 0.0;
214 fPadCoupling = 0.0;
215 fTimeCoupling = 0.0;
216 fTimeBinWidth = 0.0;
217 fField = 0.0;
218
219 fPRFbin = 0;
220 fPRFlo = 0.0;
221 fPRFhi = 0.0;
222 fPRFwid = 0.0;
223 fPRFpad = 0;
224 fTRFbin = 0;
225 fTRFlo = 0.0;
226 fTRFhi = 0.0;
227 fTRFwid = 0.0;
228
229 fCompress = kTRUE;
230 fVerbose = 0;
231 fSDigits = kFALSE;
232 fSDigitsScale = 0.0;
f7336fa3 233
234}
235
236//_____________________________________________________________________________
237AliTRDdigitizer::AliTRDdigitizer(const Text_t *name, const Text_t *title)
85cbec76 238 :AliDigitizer(name,title)
f7336fa3 239{
240 //
85cbec76 241 // AliTRDdigitizer constructor
242 //
243
244 fInputFile = NULL;
245
246 fDigitsManager = NULL;
247 fSDigitsManager = NULL;
248 fSDigitsManagerList = NULL;
249
250 fTRD = NULL;
251 fGeo = NULL;
252 fPRFsmp = NULL;
253 fTRFsmp = NULL;
254
255 fEvent = 0;
256
257 fCompress = kTRUE;
258 fVerbose = 0;
259 fSDigits = kFALSE;
260
261 Init();
262
263}
264
265//_____________________________________________________________________________
266AliTRDdigitizer::AliTRDdigitizer(AliRunDigitizer *manager
267 , const Text_t *name, const Text_t *title)
268 :AliDigitizer(manager,name,title)
269{
270 //
271 // AliTRDdigitizer constructor
f7336fa3 272 //
273
abaf1f1d 274 fInputFile = NULL;
275
276 fDigitsManager = NULL;
277 fSDigitsManager = NULL;
278 fSDigitsManagerList = NULL;
f7336fa3 279
abaf1f1d 280 fTRD = NULL;
281 fGeo = NULL;
282 fPRFsmp = NULL;
283 fTRFsmp = NULL;
f7336fa3 284
abaf1f1d 285 fEvent = 0;
286
287 fCompress = kTRUE;
288 fVerbose = 0;
289 fSDigits = kFALSE;
793ff80c 290
f7336fa3 291 Init();
292
293}
294
8230f242 295//_____________________________________________________________________________
dd9a6ee3 296AliTRDdigitizer::AliTRDdigitizer(const AliTRDdigitizer &d)
8230f242 297{
298 //
299 // AliTRDdigitizer copy constructor
300 //
301
dd9a6ee3 302 ((AliTRDdigitizer &) d).Copy(*this);
8230f242 303
304}
305
f7336fa3 306//_____________________________________________________________________________
307AliTRDdigitizer::~AliTRDdigitizer()
308{
8230f242 309 //
310 // AliTRDdigitizer destructor
311 //
f7336fa3 312
313 if (fInputFile) {
314 fInputFile->Close();
315 delete fInputFile;
abaf1f1d 316 fInputFile = NULL;
317 }
318
319 if (fDigitsManager) {
320 delete fDigitsManager;
321 fDigitsManager = NULL;
f7336fa3 322 }
323
abaf1f1d 324 if (fSDigitsManager) {
325 delete fSDigitsManager;
326 fSDigitsManager = NULL;
f7336fa3 327 }
328
abaf1f1d 329 if (fSDigitsManagerList) {
330 fSDigitsManagerList->Delete();
331 delete fSDigitsManagerList;
332 fSDigitsManagerList = NULL;
333 }
a1c3aded 334
335 if (fTRFsmp) {
336 delete fTRFsmp;
337 fTRFsmp = NULL;
338 }
339
340 if (fPRFsmp) {
341 delete fPRFsmp;
342 fPRFsmp = NULL;
343 }
344
f7336fa3 345}
346
8230f242 347//_____________________________________________________________________________
dd9a6ee3 348AliTRDdigitizer &AliTRDdigitizer::operator=(const AliTRDdigitizer &d)
349{
350 //
351 // Assignment operator
352 //
353
354 if (this != &d) ((AliTRDdigitizer &) d).Copy(*this);
355 return *this;
356
357}
358
359//_____________________________________________________________________________
360void AliTRDdigitizer::Copy(TObject &d)
8230f242 361{
362 //
363 // Copy function
364 //
365
1948ba0c 366 Int_t iBin;
367
abaf1f1d 368 ((AliTRDdigitizer &) d).fInputFile = NULL;
369 ((AliTRDdigitizer &) d).fSDigitsManagerList = NULL;
370 ((AliTRDdigitizer &) d).fSDigitsManager = NULL;
371 ((AliTRDdigitizer &) d).fDigitsManager = NULL;
372 ((AliTRDdigitizer &) d).fTRD = NULL;
373 ((AliTRDdigitizer &) d).fGeo = NULL;
374
375 ((AliTRDdigitizer &) d).fEvent = 0;
376
377 ((AliTRDdigitizer &) d).fGasGain = fGasGain;
378 ((AliTRDdigitizer &) d).fNoise = fNoise;
379 ((AliTRDdigitizer &) d).fChipGain = fChipGain;
380 ((AliTRDdigitizer &) d).fADCoutRange = fADCoutRange;
381 ((AliTRDdigitizer &) d).fADCinRange = fADCinRange;
382 ((AliTRDdigitizer &) d).fADCthreshold = fADCthreshold;
383 ((AliTRDdigitizer &) d).fDiffusionOn = fDiffusionOn;
384 ((AliTRDdigitizer &) d).fDiffusionT = fDiffusionT;
385 ((AliTRDdigitizer &) d).fDiffusionL = fDiffusionL;
386 ((AliTRDdigitizer &) d).fElAttachOn = fElAttachOn;
387 ((AliTRDdigitizer &) d).fElAttachProp = fElAttachProp;
388 ((AliTRDdigitizer &) d).fExBOn = fExBOn;
389 ((AliTRDdigitizer &) d).fOmegaTau = fOmegaTau;
390 ((AliTRDdigitizer &) d).fLorentzFactor = fLorentzFactor;
391 ((AliTRDdigitizer &) d).fDriftVelocity = fDriftVelocity;
392 ((AliTRDdigitizer &) d).fPadCoupling = fPadCoupling;
393 ((AliTRDdigitizer &) d).fTimeCoupling = fTimeCoupling;
394 ((AliTRDdigitizer &) d).fTimeBinWidth = fTimeBinWidth;
395 ((AliTRDdigitizer &) d).fField = fField;
396 ((AliTRDdigitizer &) d).fPRFOn = fPRFOn;
397 ((AliTRDdigitizer &) d).fTRFOn = fTRFOn;
398
399 ((AliTRDdigitizer &) d).fCompress = fCompress;
400 ((AliTRDdigitizer &) d).fVerbose = fVerbose;
401 ((AliTRDdigitizer &) d).fSDigits = fSDigits;
402 ((AliTRDdigitizer &) d).fSDigitsScale = fSDigitsScale;
403
404 ((AliTRDdigitizer &) d).fPRFbin = fPRFbin;
405 ((AliTRDdigitizer &) d).fPRFlo = fPRFlo;
406 ((AliTRDdigitizer &) d).fPRFhi = fPRFhi;
407 ((AliTRDdigitizer &) d).fPRFwid = fPRFwid;
408 ((AliTRDdigitizer &) d).fPRFpad = fPRFpad;
e153aaf6 409 if (((AliTRDdigitizer &) d).fPRFsmp) delete ((AliTRDdigitizer &) d).fPRFsmp;
410 ((AliTRDdigitizer &) d).fPRFsmp = new Float_t[fPRFbin];
1948ba0c 411 for (iBin = 0; iBin < fPRFbin; iBin++) {
e153aaf6 412 ((AliTRDdigitizer &) d).fPRFsmp[iBin] = fPRFsmp[iBin];
413 }
abaf1f1d 414 ((AliTRDdigitizer &) d).fTRFbin = fTRFbin;
415 ((AliTRDdigitizer &) d).fTRFlo = fTRFlo;
416 ((AliTRDdigitizer &) d).fTRFhi = fTRFhi;
417 ((AliTRDdigitizer &) d).fTRFwid = fTRFwid;
872a7aba 418 if (((AliTRDdigitizer &) d).fTRFsmp) delete ((AliTRDdigitizer &) d).fTRFsmp;
419 ((AliTRDdigitizer &) d).fTRFsmp = new Float_t[fTRFbin];
1948ba0c 420 for (iBin = 0; iBin < fTRFbin; iBin++) {
872a7aba 421 ((AliTRDdigitizer &) d).fTRFsmp[iBin] = fTRFsmp[iBin];
6244debe 422 }
423
8230f242 424}
425
f7336fa3 426//_____________________________________________________________________________
427Int_t AliTRDdigitizer::Diffusion(Float_t driftlength, Float_t *xyz)
428{
429 //
430 // Applies the diffusion smearing to the position of a single electron
431 //
432
433 Float_t driftSqrt = TMath::Sqrt(driftlength);
434 Float_t sigmaT = driftSqrt * fDiffusionT;
435 Float_t sigmaL = driftSqrt * fDiffusionL;
436 xyz[0] = gRandom->Gaus(xyz[0], sigmaL * fLorentzFactor);
437 xyz[1] = gRandom->Gaus(xyz[1], sigmaT * fLorentzFactor);
438 xyz[2] = gRandom->Gaus(xyz[2], sigmaT);
793ff80c 439
f7336fa3 440 return 1;
441
442}
443
444//_____________________________________________________________________________
445Int_t AliTRDdigitizer::ExB(Float_t driftlength, Float_t *xyz)
446{
447 //
448 // Applies E x B effects to the position of a single electron
449 //
450
451 xyz[0] = xyz[0];
793ff80c 452 xyz[1] = xyz[1] + fOmegaTau * driftlength;
f7336fa3 453 xyz[2] = xyz[2];
454
455 return 1;
456
457}
458
793ff80c 459//_____________________________________________________________________________
460Int_t AliTRDdigitizer::PadResponse(Float_t signal, Float_t dist, Float_t *pad)
461{
462 //
463 // Applies the pad response
464 //
465
e153aaf6 466 Int_t iBin = ((Int_t) (( - dist - fPRFlo) / fPRFwid));
467
468 Int_t iBin0 = iBin - fPRFpad;
469 Int_t iBin1 = iBin;
470 Int_t iBin2 = iBin + fPRFpad;
471
472 if ((iBin0 >= 0) && (iBin2 < fPRFbin)) {
473
474 pad[0] = signal * fPRFsmp[iBin0];
475 pad[1] = signal * fPRFsmp[iBin1];
476 pad[2] = signal * fPRFsmp[iBin2];
477
793ff80c 478 return 1;
e153aaf6 479
793ff80c 480 }
481 else {
e153aaf6 482
793ff80c 483 return 0;
e153aaf6 484
793ff80c 485 }
486
487}
488
489//_____________________________________________________________________________
490Float_t AliTRDdigitizer::TimeResponse(Float_t time)
491{
492 //
493 // Applies the preamp shaper time response
494 //
495
496 Int_t iBin = ((Int_t) ((time - fTRFlo) / fTRFwid));
497 if ((iBin >= 0) && (iBin < fTRFbin)) {
872a7aba 498 return fTRFsmp[iBin];
793ff80c 499 }
500 else {
501 return 0.0;
502 }
503
504}
505
f7336fa3 506//_____________________________________________________________________________
85cbec76 507Bool_t AliTRDdigitizer::Init()
f7336fa3 508{
509 //
510 // Initializes the digitization procedure with standard values
511 //
512
513 // The default parameter for the digitization
db30bf0f 514 fGasGain = 2800.;
515 fChipGain = 6.1;
6244debe 516 fNoise = 1000.;
517 fADCoutRange = 1023.; // 10-bit ADC
a3c76cdc 518 fADCinRange = 1000.; // 1V input range
6244debe 519 fADCthreshold = 1;
520
521 // For the summable digits
abaf1f1d 522 fSDigitsScale = 100.;
f7336fa3 523
db30bf0f 524 // The drift velocity (cm / mus)
525 fDriftVelocity = 1.5;
526
db30bf0f 527 // Diffusion on
6244debe 528 fDiffusionOn = 1;
db30bf0f 529
530 // E x B effects
531 fExBOn = 0;
f7336fa3 532
533 // Propability for electron attachment
6244debe 534 fElAttachOn = 0;
535 fElAttachProp = 0.0;
f7336fa3 536
da581aea 537 // The pad response function
6244debe 538 fPRFOn = 1;
872a7aba 539
540 // The time response function
541 fTRFOn = 1;
da581aea 542
6244debe 543 // The pad coupling factor (same number as for the TPC)
544 fPadCoupling = 0.5;
545
546 // The time coupling factor (same number as for the TPC)
547 fTimeCoupling = 0.4;
548
85cbec76 549 return kTRUE;
550
6244debe 551}
552
553//_____________________________________________________________________________
85cbec76 554Bool_t AliTRDdigitizer::ReInit()
6244debe 555{
556 //
872a7aba 557 // Reinitializes the digitization procedure after a change in the parameter
6244debe 558 //
559
872a7aba 560 if (!fGeo) {
561 printf("AliTRDdigitizer::ReInit -- ");
562 printf("No geometry defined. Run InitDetector() first\n");
85cbec76 563 return kFALSE;
872a7aba 564 }
565
6244debe 566 // Calculate the time bin width in ns
567 fTimeBinWidth = fGeo->GetTimeBinSize() / fDriftVelocity * 1000.0;
568
872a7aba 569 // The range and the binwidth for the sampled TRF
570 fTRFbin = 100;
db30bf0f 571 // Start 0.2 mus before the signal
572 fTRFlo = -0.2 * fDriftVelocity;
872a7aba 573 // End the maximum driftlength after the signal
574 fTRFhi = AliTRDgeometry::DrThick()
575 + fGeo->GetTimeAfter() * fGeo->GetTimeBinSize();
576 fTRFwid = (fTRFhi - fTRFlo) / ((Float_t) fTRFbin);
6244debe 577
db30bf0f 578 // Transverse and longitudinal diffusion coefficients (Xe/CO2)
579 fDiffusionT = GetDiffusionT(fDriftVelocity,fField);
580 fDiffusionL = GetDiffusionL(fDriftVelocity,fField);
581
582 // omega * tau.= tan(Lorentz-angle)
583 fOmegaTau = GetOmegaTau(fDriftVelocity,fField);
584
6244debe 585 // The Lorentz factor
586 if (fExBOn) {
587 fLorentzFactor = 1.0 / (1.0 + fOmegaTau*fOmegaTau);
588 }
589 else {
590 fLorentzFactor = 1.0;
591 }
793ff80c 592
85cbec76 593 return kTRUE;
594
793ff80c 595}
596
597//_____________________________________________________________________________
6244debe 598void AliTRDdigitizer::SampleTRF()
793ff80c 599{
600 //
6244debe 601 // Samples the time response function
872a7aba 602 // It is defined according to Vasiles simulation of the preamp shaper
603 // output and includes the effect of the ion tail (based on Tariqs
604 // Garfield simulation) and a shaping time of 125 ns FWHM
793ff80c 605 //
606
872a7aba 607 Int_t ipos1;
608 Int_t ipos2;
609 Float_t diff;
610
db30bf0f 611 const Int_t kNpasa = 200;
612 Float_t time[kNpasa] = { -0.280000, -0.270000, -0.260000, -0.250000
613 , -0.240000, -0.230000, -0.220000, -0.210000
614 , -0.200000, -0.190000, -0.180000, -0.170000
615 , -0.160000, -0.150000, -0.140000, -0.130000
616 , -0.120000, -0.110000, -0.100000, -0.090000
617 , -0.080000, -0.070000, -0.060000, -0.050000
618 , -0.040000, -0.030000, -0.020000, -0.010000
619 , -0.000000, 0.010000, 0.020000, 0.030000
620 , 0.040000, 0.050000, 0.060000, 0.070000
621 , 0.080000, 0.090000, 0.100000, 0.110000
622 , 0.120000, 0.130000, 0.140000, 0.150000
623 , 0.160000, 0.170000, 0.180000, 0.190000
624 , 0.200000, 0.210000, 0.220000, 0.230000
625 , 0.240000, 0.250000, 0.260000, 0.270000
626 , 0.280000, 0.290000, 0.300000, 0.310000
627 , 0.320000, 0.330000, 0.340000, 0.350000
628 , 0.360000, 0.370000, 0.380000, 0.390000
629 , 0.400000, 0.410000, 0.420000, 0.430000
630 , 0.440000, 0.450000, 0.460000, 0.470000
631 , 0.480000, 0.490000, 0.500000, 0.510000
632 , 0.520000, 0.530000, 0.540000, 0.550000
633 , 0.560000, 0.570000, 0.580000, 0.590000
634 , 0.600000, 0.610000, 0.620000, 0.630000
635 , 0.640000, 0.650000, 0.660000, 0.670000
636 , 0.680000, 0.690000, 0.700000, 0.710000
637 , 0.720000, 0.730000, 0.740000, 0.750000
638 , 0.760000, 0.770000, 0.780000, 0.790000
639 , 0.800000, 0.810000, 0.820000, 0.830000
640 , 0.840000, 0.850000, 0.860000, 0.870000
641 , 0.880000, 0.890000, 0.900000, 0.910000
642 , 0.920000, 0.930000, 0.940000, 0.950000
643 , 0.960000, 0.970000, 0.980000, 0.990000
644 , 1.000000, 1.010000, 1.020000, 1.030000
645 , 1.040000, 1.050000, 1.060000, 1.070000
646 , 1.080000, 1.090000, 1.100000, 1.110000
647 , 1.120000, 1.130000, 1.140000, 1.150000
648 , 1.160000, 1.170000, 1.180000, 1.190000
649 , 1.200000, 1.210000, 1.220000, 1.230000
650 , 1.240000, 1.250000, 1.260000, 1.270000
651 , 1.280000, 1.290000, 1.300000, 1.310000
652 , 1.320000, 1.330000, 1.340000, 1.350000
653 , 1.360000, 1.370000, 1.380000, 1.390000
654 , 1.400000, 1.410000, 1.420000, 1.430000
655 , 1.440000, 1.450000, 1.460000, 1.470000
656 , 1.480000, 1.490000, 1.500000, 1.510000
657 , 1.520000, 1.530000, 1.540000, 1.550000
658 , 1.560000, 1.570000, 1.580000, 1.590000
659 , 1.600000, 1.610000, 1.620000, 1.630000
660 , 1.640000, 1.650000, 1.660000, 1.670000
661 , 1.680000, 1.690000, 1.700000, 1.710000 };
662
663 Float_t signal[kNpasa] = { 0.000000, 0.000000, 0.000000, 0.000000
664 , 0.000000, 0.000000, 0.000000, 0.000000
665 , 0.000000, 0.000000, 0.000000, 0.000000
666 , 0.000000, 0.000000, 0.000000, 0.000098
667 , 0.003071, 0.020056, 0.066053, 0.148346
668 , 0.263120, 0.398496, 0.540226, 0.674436
669 , 0.790977, 0.883083, 0.947744, 0.985714
670 , 0.999248, 0.992105, 0.967669, 0.930827
671 , 0.884586, 0.833083, 0.778571, 0.723684
672 , 0.669173, 0.617293, 0.567669, 0.521805
673 , 0.479699, 0.440977, 0.405639, 0.373985
674 , 0.345526, 0.320038, 0.297256, 0.276917
675 , 0.258797, 0.242632, 0.228195, 0.215301
676 , 0.203759, 0.193383, 0.184023, 0.175564
677 , 0.167895, 0.160940, 0.154549, 0.148722
678 , 0.143308, 0.138346, 0.133722, 0.129398
679 , 0.125376, 0.121617, 0.118045, 0.114699
680 , 0.111541, 0.108571, 0.105714, 0.103008
681 , 0.100414, 0.097970, 0.095602, 0.093346
682 , 0.091165, 0.089060, 0.087068, 0.085150
683 , 0.083308, 0.081541, 0.079812, 0.078158
684 , 0.076541, 0.075000, 0.073496, 0.072068
685 , 0.070677, 0.069286, 0.068008, 0.066729
686 , 0.065489, 0.064286, 0.063120, 0.061992
687 , 0.060902, 0.059850, 0.058797, 0.057820
688 , 0.056842, 0.055902, 0.054962, 0.054060
689 , 0.053158, 0.052293, 0.051466, 0.050639
690 , 0.049850, 0.049060, 0.048308, 0.047556
691 , 0.046842, 0.046128, 0.045451, 0.044774
692 , 0.044098, 0.043459, 0.042820, 0.042218
693 , 0.041617, 0.041015, 0.040451, 0.039887
694 , 0.039323, 0.038797, 0.038271, 0.037744
695 , 0.037237, 0.036744, 0.036259, 0.035786
696 , 0.035323, 0.034872, 0.034429, 0.033996
697 , 0.033575, 0.033162, 0.032756, 0.032361
698 , 0.031974, 0.031594, 0.031222, 0.030857
699 , 0.030496, 0.030143, 0.029793, 0.029451
700 , 0.029109, 0.028774, 0.028444, 0.028113
701 , 0.027793, 0.027477, 0.027165, 0.026861
702 , 0.026564, 0.026271, 0.025981, 0.025699
703 , 0.025421, 0.025147, 0.024880, 0.024613
704 , 0.024353, 0.024094, 0.023842, 0.023590
705 , 0.023346, 0.023102, 0.022865, 0.022628
706 , 0.022398, 0.022173, 0.021951, 0.021733
707 , 0.021519, 0.021308, 0.021098, 0.020891
708 , 0.020688, 0.020485, 0.020286, 0.020090
709 , 0.019895, 0.019707, 0.019519, 0.019335
710 , 0.019150, 0.018974, 0.018797, 0.018624
711 , 0.018451, 0.018282, 0.018113, 0.017947
712 , 0.017782, 0.017617, 0.017455, 0.017297 };
713
872a7aba 714 if (fTRFsmp) delete fTRFsmp;
715 fTRFsmp = new Float_t[fTRFbin];
716
717 Float_t loTRF = TMath::Max(fTRFlo / fDriftVelocity,time[0]);
718 Float_t hiTRF = TMath::Min(fTRFhi / fDriftVelocity,time[kNpasa-1]);
793ff80c 719 Float_t binWidth = (hiTRF - loTRF) / ((Float_t) fTRFbin);
872a7aba 720
721 // Take the linear interpolation
793ff80c 722 for (Int_t iBin = 0; iBin < fTRFbin; iBin++) {
872a7aba 723
6244debe 724 Float_t bin = (((Float_t) iBin) + 0.5) * binWidth + loTRF;
872a7aba 725 ipos1 = ipos2 = 0;
726 diff = 0;
727 do {
728 diff = bin - time[ipos2++];
729 } while (diff > 0);
730 ipos2--;
731 if (ipos2 > kNpasa) ipos2 = kNpasa - 1;
732 ipos1 = ipos2 - 1;
733
734 fTRFsmp[iBin] = signal[ipos2]
735 + diff * (signal[ipos2] - signal[ipos1])
736 / ( time[ipos2] - time[ipos1]);
737
793ff80c 738 }
739
f7336fa3 740}
741
e153aaf6 742//_____________________________________________________________________________
743void AliTRDdigitizer::SamplePRF()
744{
745 //
746 // Samples the pad response function
747 //
748
db30bf0f 749 const Int_t kPRFbin = 61;
750 Float_t prf[kPRFbin] = { 0.002340, 0.003380, 0.004900, 0.007080, 0.010220
751 , 0.014740, 0.021160, 0.030230, 0.042800, 0.059830
752 , 0.082030, 0.109700, 0.142550, 0.179840, 0.220610
753 , 0.263980, 0.309180, 0.355610, 0.402790, 0.450350
754 , 0.497930, 0.545190, 0.591740, 0.637100, 0.680610
755 , 0.721430, 0.758400, 0.790090, 0.814720, 0.830480
756 , 0.835930, 0.830480, 0.814710, 0.790070, 0.758390
757 , 0.721410, 0.680590, 0.637080, 0.591730, 0.545180
758 , 0.497920, 0.450340, 0.402790, 0.355610, 0.309190
759 , 0.263990, 0.220630, 0.179850, 0.142570, 0.109720
760 , 0.082040, 0.059830, 0.042820, 0.030230, 0.021170
761 , 0.014740, 0.010230, 0.007080, 0.004900, 0.003380
762 , 0.002340 };
763
764 fPRFlo = -1.5;
765 fPRFhi = 1.5;
766 fPRFbin = kPRFbin;
767 fPRFwid = (fPRFhi - fPRFlo) / ((Float_t) fPRFbin);
768 fPRFpad = ((Int_t) (1.0 / fPRFwid));
769
e153aaf6 770 if (fPRFsmp) delete fPRFsmp;
771 fPRFsmp = new Float_t[fPRFbin];
772 for (Int_t iBin = 0; iBin < fPRFbin; iBin++) {
db30bf0f 773 fPRFsmp[iBin] = prf[iBin];
e153aaf6 774 }
775
776}
777
f7336fa3 778//_____________________________________________________________________________
779Bool_t AliTRDdigitizer::Open(const Char_t *name, Int_t nEvent)
780{
781 //
782 // Opens a ROOT-file with TRD-hits and reads in the hit-tree
783 //
784
785 // Connect the AliRoot file containing Geometry, Kine, and Hits
786 fInputFile = (TFile*) gROOT->GetListOfFiles()->FindObject(name);
787 if (!fInputFile) {
abaf1f1d 788 if (fVerbose > 0) {
789 printf("AliTRDdigitizer::Open -- ");
790 printf("Open the AliROOT-file %s.\n",name);
791 }
f7336fa3 792 fInputFile = new TFile(name,"UPDATE");
793 }
794 else {
abaf1f1d 795 if (fVerbose > 0) {
796 printf("AliTRDdigitizer::Open -- ");
797 printf("%s is already open.\n",name);
798 }
f7336fa3 799 }
800
da581aea 801 gAlice = (AliRun*) fInputFile->Get("gAlice");
802 if (gAlice) {
abaf1f1d 803 if (fVerbose > 0) {
804 printf("AliTRDdigitizer::Open -- ");
805 printf("AliRun object found on file.\n");
806 }
da581aea 807 }
808 else {
809 printf("AliTRDdigitizer::Open -- ");
810 printf("Could not find AliRun object.\n");
811 return kFALSE;
812 }
f7336fa3 813
814 fEvent = nEvent;
815
816 // Import the Trees for the event nEvent in the file
817 Int_t nparticles = gAlice->GetEvent(fEvent);
818 if (nparticles <= 0) {
819 printf("AliTRDdigitizer::Open -- ");
820 printf("No entries in the trees for event %d.\n",fEvent);
821 return kFALSE;
822 }
823
abaf1f1d 824 if (InitDetector()) {
825 return MakeBranch();
826 }
827 else {
828 return kFALSE;
829 }
793ff80c 830
831}
832
833//_____________________________________________________________________________
834Bool_t AliTRDdigitizer::InitDetector()
835{
836 //
837 // Sets the pointer to the TRD detector and the geometry
838 //
839
dd9a6ee3 840 // Get the pointer to the detector class and check for version 1
841 fTRD = (AliTRD*) gAlice->GetDetector("TRD");
842 if (fTRD->IsVersion() != 1) {
6244debe 843 printf("AliTRDdigitizer::InitDetector -- ");
dd9a6ee3 844 printf("TRD must be version 1 (slow simulator).\n");
845 exit(1);
846 }
847
848 // Get the geometry
849 fGeo = fTRD->GetGeometry();
abaf1f1d 850 if (fVerbose > 0) {
851 printf("AliTRDdigitizer::InitDetector -- ");
852 printf("Geometry version %d\n",fGeo->IsVersion());
853 }
dd9a6ee3 854
88fd7ccb 855 // The magnetic field strength in Tesla
856 fField = 0.2 * gAlice->Field()->Factor();
857
abaf1f1d 858 // Create a digits manager
859 fDigitsManager = new AliTRDdigitsManager();
860 fDigitsManager->SetSDigits(fSDigits);
861 fDigitsManager->CreateArrays();
862 fDigitsManager->SetEvent(fEvent);
863 fDigitsManager->SetVerbose(fVerbose);
864
865 // The list for the input s-digits manager to be merged
866 fSDigitsManagerList = new TList();
867
85cbec76 868 return ReInit();
f7336fa3 869
870}
871
6244debe 872//_____________________________________________________________________________
abaf1f1d 873Bool_t AliTRDdigitizer::MakeBranch(const Char_t *file)
6244debe 874{
abaf1f1d 875 //
876 // Create the branches for the digits array
6244debe 877 //
878
abaf1f1d 879 return fDigitsManager->MakeBranch(file);
6244debe 880
881}
882
f7336fa3 883//_____________________________________________________________________________
884Bool_t AliTRDdigitizer::MakeDigits()
885{
886 //
872a7aba 887 // Creates digits.
f7336fa3 888 //
889
f7336fa3 890 ///////////////////////////////////////////////////////////////
891 // Parameter
892 ///////////////////////////////////////////////////////////////
893
894 // Converts number of electrons to fC
872a7aba 895 const Double_t kEl2fC = 1.602E-19 * 1.0E15;
f7336fa3 896
897 ///////////////////////////////////////////////////////////////
898
793ff80c 899 // Number of pads included in the pad response
900 const Int_t kNpad = 3;
901
902 // Number of track dictionary arrays
dd56b762 903 const Int_t kNDict = AliTRDdigitsManager::kNDict;
793ff80c 904
872a7aba 905 // Half the width of the amplification region
906 const Float_t kAmWidth = AliTRDgeometry::AmThick() / 2.;
907
c3a4830f 908 Int_t iRow, iCol, iTime, iPad;
71d9fa7b 909 Int_t iDict = 0;
793ff80c 910 Int_t nBytes = 0;
f7336fa3 911
912 Int_t totalSizeDigits = 0;
913 Int_t totalSizeDict0 = 0;
914 Int_t totalSizeDict1 = 0;
915 Int_t totalSizeDict2 = 0;
916
872a7aba 917 Int_t timeTRDbeg = 0;
918 Int_t timeTRDend = 1;
919
920 Float_t pos[3];
921 Float_t rot[3];
922 Float_t xyz[3];
923 Float_t padSignal[kNpad];
924 Float_t signalOld[kNpad];
925
793ff80c 926 AliTRDdataArrayF *signals = 0;
927 AliTRDdataArrayI *digits = 0;
8230f242 928 AliTRDdataArrayI *dictionary[kNDict];
da581aea 929
793ff80c 930 // Create a container for the amplitudes
931 AliTRDsegmentArray *signalsArray
932 = new AliTRDsegmentArray("AliTRDdataArrayF",AliTRDgeometry::Ndet());
933
872a7aba 934 if (fTRFOn) {
935 timeTRDbeg = ((Int_t) (-fTRFlo / fGeo->GetTimeBinSize())) - 1;
936 timeTRDend = ((Int_t) ( fTRFhi / fGeo->GetTimeBinSize())) - 1;
abaf1f1d 937 if (fVerbose > 0) {
938 printf("AliTRDdigitizer::MakeDigits -- ");
939 printf("Sample the TRF between -%d and %d\n",timeTRDbeg,timeTRDend);
940 }
da581aea 941 }
942
872a7aba 943 Float_t elAttachProp = fElAttachProp / 100.;
f7336fa3 944
e153aaf6 945 // Create the sampled PRF
946 SamplePRF();
947
6244debe 948 // Create the sampled TRF
949 SampleTRF();
793ff80c 950
872a7aba 951 if (!fGeo) {
952 printf("AliTRDdigitizer::MakeDigits -- ");
953 printf("No geometry defined\n");
954 return kFALSE;
955 }
956
abaf1f1d 957 if (fVerbose > 0) {
958 printf("AliTRDdigitizer::MakeDigits -- ");
959 printf("Start creating digits.\n");
960 }
872a7aba 961
793ff80c 962 // Get the pointer to the hit tree
963 TTree *HitTree = gAlice->TreeH();
964
965 // Get the number of entries in the hit tree
966 // (Number of primary particles creating a hit somewhere)
967 Int_t nTrack = (Int_t) HitTree->GetEntries();
968 if (fVerbose > 0) {
969 printf("AliTRDdigitizer::MakeDigits -- ");
970 printf("Found %d primary particles\n",nTrack);
971 }
972
973 Int_t detectorOld = -1;
974 Int_t countHits = 0;
975
976 // Loop through all entries in the tree
977 for (Int_t iTrack = 0; iTrack < nTrack; iTrack++) {
978
979 gAlice->ResetHits();
980 nBytes += HitTree->GetEvent(iTrack);
981
982 // Get the number of hits in the TRD created by this particle
983 Int_t nHit = fTRD->Hits()->GetEntriesFast();
984 if (fVerbose > 0) {
985 printf("AliTRDdigitizer::MakeDigits -- ");
986 printf("Found %d hits for primary particle %d\n",nHit,iTrack);
987 }
988
989 // Loop through the TRD hits
990 for (Int_t iHit = 0; iHit < nHit; iHit++) {
991
992 countHits++;
993
994 AliTRDhit *hit = (AliTRDhit *) fTRD->Hits()->UncheckedAt(iHit);
793ff80c 995 pos[0] = hit->X();
996 pos[1] = hit->Y();
997 pos[2] = hit->Z();
998 Float_t q = hit->GetCharge();
999 Int_t track = hit->Track();
1000 Int_t detector = hit->GetDetector();
1001 Int_t plane = fGeo->GetPlane(detector);
1002 Int_t sector = fGeo->GetSector(detector);
1003 Int_t chamber = fGeo->GetChamber(detector);
1004
1005 if (!(CheckDetector(plane,chamber,sector))) continue;
1006
1007 Int_t nRowMax = fGeo->GetRowMax(plane,chamber,sector);
1008 Int_t nColMax = fGeo->GetColMax(plane);
1009 Int_t nTimeMax = fGeo->GetTimeMax();
872a7aba 1010 Int_t nTimeBefore = fGeo->GetTimeBefore();
1011 Int_t nTimeAfter = fGeo->GetTimeAfter();
1012 Int_t nTimeTotal = fGeo->GetTimeTotal();
793ff80c 1013 Float_t row0 = fGeo->GetRow0(plane,chamber,sector);
1014 Float_t col0 = fGeo->GetCol0(plane);
1015 Float_t time0 = fGeo->GetTime0(plane);
71d9fa7b 1016 Float_t rowPadSize = fGeo->GetRowPadSize(plane,chamber,sector);
1017 Float_t colPadSize = fGeo->GetColPadSize(plane);
793ff80c 1018 Float_t timeBinSize = fGeo->GetTimeBinSize();
872a7aba 1019 Float_t divideRow = 1.0 / rowPadSize;
1020 Float_t divideCol = 1.0 / colPadSize;
1021 Float_t divideTime = 1.0 / timeBinSize;
793ff80c 1022
1023 if (fVerbose > 1) {
1024 printf("Analyze hit no. %d ",iHit);
1025 printf("-----------------------------------------------------------\n");
1026 hit->Dump();
1027 printf("plane = %d, sector = %d, chamber = %d\n"
1028 ,plane,sector,chamber);
1029 printf("nRowMax = %d, nColMax = %d, nTimeMax = %d\n"
1030 ,nRowMax,nColMax,nTimeMax);
872a7aba 1031 printf("nTimeBefore = %d, nTimeAfter = %d, nTimeTotal = %d\n"
1032 ,nTimeBefore,nTimeAfter,nTimeTotal);
793ff80c 1033 printf("row0 = %f, col0 = %f, time0 = %f\n"
1034 ,row0,col0,time0);
c1e4b257 1035 printf("rowPadSize = %f, colPadSize = %f, timeBinSize = %f\n"
1036 ,rowPadSize,colPadSize,timeBinSize);
793ff80c 1037 }
1038
872a7aba 1039 // Don't analyze test hits
1040 if (hit->FromTest()) continue;
dd56b762 1041
793ff80c 1042 if (detector != detectorOld) {
e153aaf6 1043
793ff80c 1044 if (fVerbose > 1) {
1045 printf("AliTRDdigitizer::MakeDigits -- ");
1046 printf("Get new container. New det = %d, Old det = %d\n"
1047 ,detector,detectorOld);
1048 }
1049 // Compress the old one if enabled
1050 if ((fCompress) && (detectorOld > -1)) {
1051 if (fVerbose > 1) {
1052 printf("AliTRDdigitizer::MakeDigits -- ");
e153aaf6 1053 printf("Compress the old container ...");
dd9a6ee3 1054 }
793ff80c 1055 signals->Compress(1,0);
1056 for (iDict = 0; iDict < kNDict; iDict++) {
1057 dictionary[iDict]->Compress(1,0);
dd9a6ee3 1058 }
793ff80c 1059 if (fVerbose > 1) printf("done\n");
9d0b222b 1060 }
793ff80c 1061 // Get the new container
1062 signals = (AliTRDdataArrayF *) signalsArray->At(detector);
1063 if (signals->GetNtime() == 0) {
1064 // Allocate a new one if not yet existing
1065 if (fVerbose > 1) {
1066 printf("AliTRDdigitizer::MakeDigits -- ");
1067 printf("Allocate a new container ... ");
1068 }
872a7aba 1069 signals->Allocate(nRowMax,nColMax,nTimeTotal);
793ff80c 1070 }
1071 else {
1072 // Expand an existing one
c1e4b257 1073 if (fCompress) {
1074 if (fVerbose > 1) {
1075 printf("AliTRDdigitizer::MakeDigits -- ");
1076 printf("Expand an existing container ... ");
1077 }
1078 signals->Expand();
793ff80c 1079 }
793ff80c 1080 }
1081 // The same for the dictionary
1082 for (iDict = 0; iDict < kNDict; iDict++) {
abaf1f1d 1083 dictionary[iDict] = fDigitsManager->GetDictionary(detector,iDict);
793ff80c 1084 if (dictionary[iDict]->GetNtime() == 0) {
872a7aba 1085 dictionary[iDict]->Allocate(nRowMax,nColMax,nTimeTotal);
793ff80c 1086 }
1087 else {
1088 if (fCompress) dictionary[iDict]->Expand();
1089 }
1090 }
1091 if (fVerbose > 1) printf("done\n");
1092 detectorOld = detector;
1093 }
9d0b222b 1094
793ff80c 1095 // Rotate the sectors on top of each other
793ff80c 1096 fGeo->Rotate(detector,pos,rot);
1097
872a7aba 1098 // The driftlength. It is negative if the hit is in the
1099 // amplification region.
793ff80c 1100 Float_t driftlength = time0 - rot[0];
793ff80c 1101
872a7aba 1102 // Take also the drift in the amplification region into account
1103 // The drift length is at the moment still the same, regardless of
1104 // the position relativ to the wire. This non-isochronity needs still
1105 // to be implemented.
1106 Float_t driftlengthL = TMath::Abs(driftlength + kAmWidth);
1107 if (fExBOn) driftlengthL /= TMath::Sqrt(fLorentzFactor);
793ff80c 1108
1109 // Loop over all electrons of this hit
1110 // TR photons produce hits with negative charge
1111 Int_t nEl = ((Int_t) TMath::Abs(q));
1112 for (Int_t iEl = 0; iEl < nEl; iEl++) {
1113
793ff80c 1114 xyz[0] = rot[0];
1115 xyz[1] = rot[1];
1116 xyz[2] = rot[2];
1117
1118 // Electron attachment
1119 if (fElAttachOn) {
872a7aba 1120 if (gRandom->Rndm() < (driftlengthL * elAttachProp))
793ff80c 1121 continue;
1122 }
1123
1124 // Apply the diffusion smearing
1125 if (fDiffusionOn) {
1126 if (!(Diffusion(driftlengthL,xyz))) continue;
da581aea 1127 }
f7336fa3 1128
872a7aba 1129 // Apply E x B effects (depends on drift direction)
793ff80c 1130 if (fExBOn) {
872a7aba 1131 if (!(ExB(driftlength+kAmWidth,xyz))) continue;
793ff80c 1132 }
f7336fa3 1133
872a7aba 1134 // The electron position after diffusion and ExB in pad coordinates
793ff80c 1135 // The pad row (z-direction)
872a7aba 1136 Int_t rowE = ((Int_t) ((xyz[2] - row0) * divideRow));
1137 if ((rowE < 0) || (rowE >= nRowMax)) continue;
793ff80c 1138
872a7aba 1139 // The pad column (rphi-direction)
1140 Int_t colE = ((Int_t) ((xyz[1] - col0) * divideCol));
1141 if ((colE < 0) || (colE >= nColMax)) continue;
1142
1143 // The time bin (negative for hits in the amplification region)
1144 // In the amplification region the electrons drift from both sides
1145 // to the middle (anode wire plane)
1146 Float_t timeDist = time0 - xyz[0];
1147 Float_t timeOffset = 0;
1148 Int_t timeE = 0;
1149 if (timeDist > 0) {
1150 // The time bin
1151 timeE = ((Int_t) (timeDist * divideTime));
1152 // The distance of the position to the middle of the timebin
1153 timeOffset = ((((Float_t) timeE) + 0.5) * timeBinSize) - timeDist;
1154 }
1155 else {
1156 // Difference between half of the amplification gap width and
1157 // the distance to the anode wire
1158 Float_t anodeDist = kAmWidth - TMath::Abs(timeDist + kAmWidth);
1159 // The time bin
1160 timeE = -1 * (((Int_t ) (anodeDist * divideTime)) + 1);
1161 // The distance of the position to the middle of the timebin
1162 timeOffset = ((((Float_t) timeE) + 0.5) * timeBinSize) + anodeDist;
1163 }
1164
793ff80c 1165 // Apply the gas gain including fluctuations
1166 Float_t ggRndm = 0.0;
1167 do {
1168 ggRndm = gRandom->Rndm();
1169 } while (ggRndm <= 0);
1170 Int_t signal = (Int_t) (-fGasGain * TMath::Log(ggRndm));
1171
793ff80c 1172 // Apply the pad response
793ff80c 1173 if (fPRFOn) {
1174 // The distance of the electron to the center of the pad
1175 // in units of pad width
1176 Float_t dist = (xyz[1] - col0 - (colE + 0.5) * colPadSize)
872a7aba 1177 * divideCol;
793ff80c 1178 if (!(PadResponse(signal,dist,padSignal))) continue;
1179 }
1180 else {
1181 padSignal[0] = 0.0;
1182 padSignal[1] = signal;
1183 padSignal[2] = 0.0;
1184 }
f7336fa3 1185
872a7aba 1186 // Sample the time response inside the drift region
1187 // + additional time bins before and after.
1188 // The sampling is done always in the middle of the time bin
1189 for (Int_t iTimeBin = TMath::Max(timeE-timeTRDbeg, -nTimeBefore)
1190 ;iTimeBin < TMath::Min(timeE+timeTRDend,nTimeMax+nTimeAfter )
6244debe 1191 ;iTimeBin++) {
793ff80c 1192
1193 // Apply the time response
1194 Float_t timeResponse = 1.0;
1195 if (fTRFOn) {
1196 Float_t time = (iTimeBin - timeE) * timeBinSize + timeOffset;
1197 timeResponse = TimeResponse(time);
1198 }
f7336fa3 1199
872a7aba 1200 signalOld[0] = 0.0;
1201 signalOld[1] = 0.0;
1202 signalOld[2] = 0.0;
1203
c3a4830f 1204 for (iPad = 0; iPad < kNpad; iPad++) {
872a7aba 1205
793ff80c 1206 Int_t colPos = colE + iPad - 1;
1207 if (colPos < 0) continue;
1208 if (colPos >= nColMax) break;
872a7aba 1209
1210 // Add the signals
1211 // Note: The time bin number is shifted by nTimeBefore to avoid negative
db30bf0f 1212 // time bins. This has to be subtracted later.
872a7aba 1213 Int_t iCurrentTimeBin = iTimeBin + nTimeBefore;
1214 signalOld[iPad] = signals->GetDataUnchecked(rowE,colPos,iCurrentTimeBin);
793ff80c 1215 signalOld[iPad] += padSignal[iPad] * timeResponse;
872a7aba 1216 signals->SetDataUnchecked(rowE,colPos,iCurrentTimeBin,signalOld[iPad]);
f7336fa3 1217
872a7aba 1218 // Store the track index in the dictionary
1219 // Note: We store index+1 in order to allow the array to be compressed
1220 if (signalOld[iPad] > 0) {
71d9fa7b 1221 for (iDict = 0; iDict < kNDict; iDict++) {
872a7aba 1222 Int_t oldTrack = dictionary[iDict]->GetDataUnchecked(rowE
1223 ,colPos
1224 ,iCurrentTimeBin);
71d9fa7b 1225 if (oldTrack == track+1) break;
71d9fa7b 1226 if (oldTrack == 0) {
872a7aba 1227 dictionary[iDict]->SetDataUnchecked(rowE,colPos,iCurrentTimeBin,track+1);
71d9fa7b 1228 break;
1229 }
1230 }
793ff80c 1231 }
872a7aba 1232
1233 }
f7336fa3 1234
f7336fa3 1235 }
1236
793ff80c 1237 }
f7336fa3 1238
793ff80c 1239 }
f7336fa3 1240
793ff80c 1241 } // All hits finished
f7336fa3 1242
abaf1f1d 1243 if (fVerbose > 0) {
1244 printf("AliTRDdigitizer::MakeDigits -- ");
1245 printf("Finished analyzing %d hits\n",countHits);
1246 }
793ff80c 1247
6244debe 1248 // The total conversion factor
1249 Float_t convert = kEl2fC * fPadCoupling * fTimeCoupling * fChipGain;
1250
793ff80c 1251 // Loop through all chambers to finalize the digits
1252 for (Int_t iDet = 0; iDet < AliTRDgeometry::Ndet(); iDet++) {
1253
872a7aba 1254 Int_t plane = fGeo->GetPlane(iDet);
1255 Int_t sector = fGeo->GetSector(iDet);
1256 Int_t chamber = fGeo->GetChamber(iDet);
1257 Int_t nRowMax = fGeo->GetRowMax(plane,chamber,sector);
1258 Int_t nColMax = fGeo->GetColMax(plane);
1259 Int_t nTimeMax = fGeo->GetTimeMax();
1260 Int_t nTimeTotal = fGeo->GetTimeTotal();
793ff80c 1261
793ff80c 1262 if (fVerbose > 0) {
1263 printf("AliTRDdigitizer::MakeDigits -- ");
1264 printf("Digitization for chamber %d\n",iDet);
1265 }
da581aea 1266
793ff80c 1267 // Add a container for the digits of this detector
abaf1f1d 1268 digits = fDigitsManager->GetDigits(iDet);
793ff80c 1269 // Allocate memory space for the digits buffer
872a7aba 1270 digits->Allocate(nRowMax,nColMax,nTimeTotal);
da581aea 1271
793ff80c 1272 // Get the signal container
1273 signals = (AliTRDdataArrayF *) signalsArray->At(iDet);
1274 if (signals->GetNtime() == 0) {
1275 // Create missing containers
872a7aba 1276 signals->Allocate(nRowMax,nColMax,nTimeTotal);
793ff80c 1277 }
1278 else {
1279 // Expand the container if neccessary
1280 if (fCompress) signals->Expand();
1281 }
1282 // Create the missing dictionary containers
1283 for (iDict = 0; iDict < kNDict; iDict++) {
abaf1f1d 1284 dictionary[iDict] = fDigitsManager->GetDictionary(iDet,iDict);
793ff80c 1285 if (dictionary[iDict]->GetNtime() == 0) {
872a7aba 1286 dictionary[iDict]->Allocate(nRowMax,nColMax,nTimeTotal);
793ff80c 1287 }
1288 }
f7336fa3 1289
793ff80c 1290 Int_t nDigits = 0;
1291
6244debe 1292 // Don't create noise in detectors that are switched off
1293 if (CheckDetector(plane,chamber,sector)) {
1294
1295 // Create the digits for this chamber
872a7aba 1296 for (iRow = 0; iRow < nRowMax; iRow++ ) {
1297 for (iCol = 0; iCol < nColMax; iCol++ ) {
1298 for (iTime = 0; iTime < nTimeTotal; iTime++) {
6244debe 1299
1300 // Create summable digits
1301 if (fSDigits) {
1302
872a7aba 1303 Float_t signalAmp = signals->GetDataUnchecked(iRow,iCol,iTime);
abaf1f1d 1304 signalAmp *= fSDigitsScale;
20c69486 1305 signalAmp = TMath::Min(signalAmp,(Float_t)1.0e9);
abaf1f1d 1306 Int_t adc = (Int_t) signalAmp;
6244debe 1307 nDigits++;
872a7aba 1308 digits->SetDataUnchecked(iRow,iCol,iTime,adc);
f7336fa3 1309
c1e4b257 1310 }
6244debe 1311 // Create normal digits
1312 else {
1313
872a7aba 1314 Float_t signalAmp = signals->GetDataUnchecked(iRow,iCol,iTime);
6244debe 1315
1316 // Add the noise
1317 signalAmp = TMath::Max((Double_t) gRandom->Gaus(signalAmp,fNoise),0.0);
1318 // Convert to mV
1319 signalAmp *= convert;
1320 // Convert to ADC counts. Set the overflow-bit fADCoutRange if the
1321 // signal is larger than fADCinRange
1322 Int_t adc = 0;
1323 if (signalAmp >= fADCinRange) {
1324 adc = ((Int_t) fADCoutRange);
1325 }
1326 else {
1327 adc = ((Int_t) (signalAmp * (fADCoutRange / fADCinRange)));
1328 }
1329
1330 // Store the amplitude of the digit if above threshold
1331 if (adc > fADCthreshold) {
1332 if (fVerbose > 2) {
1333 printf(" iRow = %d, iCol = %d, iTime = %d\n"
1334 ,iRow,iCol,iTime);
1335 printf(" signal = %f, adc = %d\n",signalAmp,adc);
1336 }
1337 nDigits++;
872a7aba 1338 digits->SetDataUnchecked(iRow,iCol,iTime,adc);
6244debe 1339 }
f7336fa3 1340
6244debe 1341 }
1342
1343 }
1344 }
793ff80c 1345 }
6244debe 1346
793ff80c 1347 }
1348
1349 // Compress the arrays
1350 digits->Compress(1,0);
1351 for (iDict = 0; iDict < kNDict; iDict++) {
1352 dictionary[iDict]->Compress(1,0);
1353 }
f7336fa3 1354
793ff80c 1355 totalSizeDigits += digits->GetSize();
1356 totalSizeDict0 += dictionary[0]->GetSize();
1357 totalSizeDict1 += dictionary[1]->GetSize();
1358 totalSizeDict2 += dictionary[2]->GetSize();
f7336fa3 1359
c1e4b257 1360 Float_t nPixel = nRowMax * nColMax * nTimeMax;
abaf1f1d 1361 if (fVerbose > 0) {
1362 printf("AliTRDdigitizer::MakeDigits -- ");
1363 printf("Found %d digits in detector %d (%3.0f).\n"
1364 ,nDigits,iDet
1365 ,100.0 * ((Float_t) nDigits) / nPixel);
1366 }
1367
793ff80c 1368 if (fCompress) signals->Compress(1,0);
f7336fa3 1369
f7336fa3 1370 }
1371
abaf1f1d 1372 if (fVerbose > 0) {
1373 printf("AliTRDdigitizer::MakeDigits -- ");
1374 printf("Total number of analyzed hits = %d\n",countHits);
1375 printf("AliTRDdigitizer::MakeDigits -- ");
1376 printf("Total digits data size = %d, %d, %d, %d\n",totalSizeDigits
1377 ,totalSizeDict0
1378 ,totalSizeDict1
1379 ,totalSizeDict2);
1380 }
1381
1382 return kTRUE;
1383
1384}
1385
1386//_____________________________________________________________________________
1387void AliTRDdigitizer::AddSDigitsManager(AliTRDdigitsManager *man)
1388{
1389 //
1390 // Add a digits manager for s-digits to the input list.
1391 //
1392
1393 fSDigitsManagerList->Add(man);
1394
1395}
1396
1397//_____________________________________________________________________________
1398Bool_t AliTRDdigitizer::ConvertSDigits()
1399{
1400 //
1401 // Converts s-digits to normal digits
1402 //
1403
1404 // Number of track dictionary arrays
1405 const Int_t kNDict = AliTRDdigitsManager::kNDict;
1406
1407 // Converts number of electrons to fC
1408 const Double_t kEl2fC = 1.602E-19 * 1.0E15;
1409
1410 Int_t iDict = 0;
1411
1412 if (fVerbose > 0) {
1413 this->Dump();
1414 }
1415
1416 Double_t sDigitsScale = 1.0 / GetSDigitsScale();
1417 Double_t noise = GetNoise();
1418 Double_t padCoupling = GetPadCoupling();
1419 Double_t timeCoupling = GetTimeCoupling();
1420 Double_t chipGain = GetChipGain();
1421 Double_t convert = kEl2fC * padCoupling * timeCoupling * chipGain;;
1422 Double_t adcInRange = GetADCinRange();
1423 Double_t adcOutRange = GetADCoutRange();
1424 Int_t adcThreshold = GetADCthreshold();
1425
1426 AliTRDdataArrayI *digitsIn;
1427 AliTRDdataArrayI *digitsOut;
1428 AliTRDdataArrayI *dictionaryIn[kNDict];
1429 AliTRDdataArrayI *dictionaryOut[kNDict];
1430
1431 // Loop through the detectors
1432 for (Int_t iDet = 0; iDet < AliTRDgeometry::Ndet(); iDet++) {
da581aea 1433
abaf1f1d 1434 if (fVerbose > 0) {
1435 printf("AliTRDdigitizer::ConvertSDigits -- ");
1436 printf("Convert detector %d to digits.\n",iDet);
1437 }
1438
1439 Int_t plane = fGeo->GetPlane(iDet);
1440 Int_t sector = fGeo->GetSector(iDet);
1441 Int_t chamber = fGeo->GetChamber(iDet);
1442 Int_t nRowMax = fGeo->GetRowMax(plane,chamber,sector);
1443 Int_t nColMax = fGeo->GetColMax(plane);
1444 Int_t nTimeTotal = fGeo->GetTimeTotal();
1445
1446 digitsIn = fSDigitsManager->GetDigits(iDet);
1447 digitsIn->Expand();
1448 digitsOut = fDigitsManager->GetDigits(iDet);
1449 digitsOut->Allocate(nRowMax,nColMax,nTimeTotal);
1450 for (iDict = 0; iDict < kNDict; iDict++) {
1451 dictionaryIn[iDict] = fSDigitsManager->GetDictionary(iDet,iDict);
1452 dictionaryIn[iDict]->Expand();
1453 dictionaryOut[iDict] = fDigitsManager->GetDictionary(iDet,iDict);
1454 dictionaryOut[iDict]->Allocate(nRowMax,nColMax,nTimeTotal);
1455 }
1456
1457 for (Int_t iRow = 0; iRow < nRowMax; iRow++ ) {
1458 for (Int_t iCol = 0; iCol < nColMax; iCol++ ) {
1459 for (Int_t iTime = 0; iTime < nTimeTotal; iTime++) {
1460
1461 Double_t signal = (Double_t) digitsIn->GetDataUnchecked(iRow,iCol,iTime);
1462 signal *= sDigitsScale;
1463 // Add the noise
1464 signal = TMath::Max((Double_t) gRandom->Gaus(signal,noise),0.0);
1465 // Convert to mV
1466 signal *= convert;
1467 // Convert to ADC counts. Set the overflow-bit adcOutRange if the
1468 // signal is larger than adcInRange
1469 Int_t adc = 0;
1470 if (signal >= adcInRange) {
1471 adc = ((Int_t) adcOutRange);
1472 }
1473 else {
1474 adc = ((Int_t) (signal * (adcOutRange / adcInRange)));
1475 }
1476 // Store the amplitude of the digit if above threshold
1477 if (adc > adcThreshold) {
1478 digitsOut->SetDataUnchecked(iRow,iCol,iTime,adc);
1479 }
1480 // Copy the dictionary
1481 for (iDict = 0; iDict < kNDict; iDict++) {
1482 Int_t track = dictionaryIn[iDict]->GetDataUnchecked(iRow,iCol,iTime);
1483 dictionaryOut[iDict]->SetDataUnchecked(iRow,iCol,iTime,track);
1484 }
1485
1486 }
1487 }
1488 }
1489
1490 if (fCompress) {
1491 digitsIn->Compress(1,0);
1492 digitsOut->Compress(1,0);
1493 for (iDict = 0; iDict < kNDict; iDict++) {
1494 dictionaryIn[iDict]->Compress(1,0);
1495 dictionaryOut[iDict]->Compress(1,0);
1496 }
1497 }
1498
1499 }
f7336fa3 1500
1501 return kTRUE;
1502
1503}
1504
16bf9884 1505//_____________________________________________________________________________
abaf1f1d 1506Bool_t AliTRDdigitizer::MergeSDigits()
16bf9884 1507{
1508 //
abaf1f1d 1509 // Merges the input s-digits:
1510 // - The amplitude of the different inputs are summed up.
1511 // - Of the track IDs from the input dictionaries only one is
1512 // kept for each input. This works for maximal 3 different merged inputs.
16bf9884 1513 //
1514
abaf1f1d 1515 // Number of track dictionary arrays
1516 const Int_t kNDict = AliTRDdigitsManager::kNDict;
1517
1518 Int_t iDict = 0;
1519
1520 AliTRDdataArrayI *digitsA;
1521 AliTRDdataArrayI *digitsB;
1522 AliTRDdataArrayI *dictionaryA[kNDict];
1523 AliTRDdataArrayI *dictionaryB[kNDict];
1524
1525 // Get the first s-digits
1526 fSDigitsManager = (AliTRDdigitsManager *) fSDigitsManagerList->First();
1527 if (!fSDigitsManager) return kFALSE;
1528
1529 // Loop through the other sets of s-digits
1530 AliTRDdigitsManager *mergeSDigitsManager;
1531 mergeSDigitsManager = (AliTRDdigitsManager *)
1532 fSDigitsManagerList->After(fSDigitsManager);
1533
1534 if (fVerbose > 0) {
1535 if (mergeSDigitsManager) {
1536 printf("AliTRDdigitizer::MergeSDigits -- ");
1537 printf("Merge serveral input files.\n");
1538 }
1539 else {
1540 printf("AliTRDdigitizer::MergeSDigits -- ");
1541 printf("Only one input file.\n");
1542 }
1543 }
1544
1545 Int_t iMerge = 0;
1546 while (mergeSDigitsManager) {
1547
1548 iMerge++;
1549
1550 // Loop through the detectors
1551 for (Int_t iDet = 0; iDet < AliTRDgeometry::Ndet(); iDet++) {
1552
1553 Int_t plane = fGeo->GetPlane(iDet);
1554 Int_t sector = fGeo->GetSector(iDet);
1555 Int_t chamber = fGeo->GetChamber(iDet);
1556 Int_t nRowMax = fGeo->GetRowMax(plane,chamber,sector);
1557 Int_t nColMax = fGeo->GetColMax(plane);
1558 Int_t nTimeTotal = fGeo->GetTimeTotal();
1559
1560 // Loop through the pixels of one detector and add the signals
1561 digitsA = fSDigitsManager->GetDigits(iDet);
1562 digitsB = mergeSDigitsManager->GetDigits(iDet);
1563 digitsA->Expand();
1564 digitsB->Expand();
1565 for (iDict = 0; iDict < kNDict; iDict++) {
1566 dictionaryA[iDict] = fSDigitsManager->GetDictionary(iDet,iDict);
1567 dictionaryB[iDict] = mergeSDigitsManager->GetDictionary(iDet,iDict);
1568 dictionaryA[iDict]->Expand();
1569 dictionaryB[iDict]->Expand();
1570 }
1571
1572 if (fVerbose > 0) {
1573 printf("AliTRDdigitizer::MergeSDigits -- ");
1574 printf("Merge detector %d of input no.%d.\n",iDet,iMerge);
1575 }
1576
1577 for (Int_t iRow = 0; iRow < nRowMax; iRow++ ) {
1578 for (Int_t iCol = 0; iCol < nColMax; iCol++ ) {
1579 for (Int_t iTime = 0; iTime < nTimeTotal; iTime++) {
1580
1581 // Add the amplitudes of the summable digits
1582 Int_t ampA = digitsA->GetDataUnchecked(iRow,iCol,iTime);
1583 Int_t ampB = digitsB->GetDataUnchecked(iRow,iCol,iTime);
1584 ampA += ampB;
1585 digitsA->SetDataUnchecked(iRow,iCol,iTime,ampA);
1586
1587 // Take only one track from each input
1588 Int_t track = dictionaryB[0]->GetDataUnchecked(iRow,iCol,iTime);
1589 if (iMerge < kNDict) {
1590 dictionaryA[iMerge]->SetDataUnchecked(iRow,iCol,iTime,track);
1591 }
1592
1593 }
1594 }
1595 }
1596
1597 if (fCompress) {
1598 digitsA->Compress(1,0);
1599 digitsB->Compress(1,0);
1600 for (iDict = 0; iDict < kNDict; iDict++) {
1601 dictionaryA[iDict]->Compress(1,0);
1602 dictionaryB[iDict]->Compress(1,0);
1603 }
1604 }
1605
1606 }
1607
1608 // The next set of s-digits
1609 mergeSDigitsManager = (AliTRDdigitsManager *)
1610 fSDigitsManagerList->After(mergeSDigitsManager);
1611
1612 }
1613
16bf9884 1614 return kTRUE;
1615
1616}
1617
abaf1f1d 1618//_____________________________________________________________________________
1619Bool_t AliTRDdigitizer::SDigits2Digits()
1620{
1621 //
1622 // Merges the input s-digits and converts them to normal digits
1623 //
1624
1625 if (!MergeSDigits()) return kFALSE;
1626
1627 return ConvertSDigits();
1628
1629}
1630
793ff80c 1631//_____________________________________________________________________________
1632Bool_t AliTRDdigitizer::CheckDetector(Int_t plane, Int_t chamber, Int_t sector)
1633{
1634 //
1635 // Checks whether a detector is enabled
1636 //
1637
1638 if ((fTRD->GetSensChamber() >= 0) &&
1639 (fTRD->GetSensChamber() != chamber)) return kFALSE;
1640 if ((fTRD->GetSensPlane() >= 0) &&
c1e4b257 1641 (fTRD->GetSensPlane() != plane)) return kFALSE;
793ff80c 1642 if ( fTRD->GetSensSector() >= 0) {
1643 Int_t sens1 = fTRD->GetSensSector();
1644 Int_t sens2 = sens1 + fTRD->GetSensSectorRange();
1645 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
1646 * AliTRDgeometry::Nsect();
1647 if (sens1 < sens2) {
1648 if ((sector < sens1) || (sector >= sens2)) return kFALSE;
1649 }
1650 else {
1651 if ((sector < sens1) && (sector >= sens2)) return kFALSE;
1652 }
1653 }
1654
1655 return kTRUE;
1656
1657}
1658
f7336fa3 1659//_____________________________________________________________________________
1660Bool_t AliTRDdigitizer::WriteDigits()
1661{
1662 //
1663 // Writes out the TRD-digits and the dictionaries
1664 //
1665
da581aea 1666 // Store the digits and the dictionary in the tree
abaf1f1d 1667 return fDigitsManager->WriteDigits();
f7336fa3 1668
1669}
793ff80c 1670
1671//_____________________________________________________________________________
db30bf0f 1672Float_t AliTRDdigitizer::GetDiffusionL(Float_t vd, Float_t b)
793ff80c 1673{
1674 //
db30bf0f 1675 // Returns the longitudinal diffusion coefficient for a given drift
1676 // velocity <vd> and a B-field <b> for Xe/CO2 (15%).
1677 // The values are according to a GARFIELD simulation.
793ff80c 1678 //
1679
db30bf0f 1680 const Int_t kNb = 5;
1681 Float_t p0[kNb] = { 0.007440, 0.007493, 0.007513, 0.007672, 0.007831 };
1682 Float_t p1[kNb] = { 0.019252, 0.018912, 0.018636, 0.018012, 0.017343 };
1683 Float_t p2[kNb] = { -0.005042, -0.004926, -0.004867, -0.004650, -0.004424 };
1684 Float_t p3[kNb] = { 0.000195, 0.000189, 0.000195, 0.000182, 0.000169 };
1685
1686 Int_t ib = ((Int_t) (10 * (b - 0.15)));
1687 ib = TMath::Max( 0,ib);
1688 ib = TMath::Min(kNb,ib);
1689
1690 Float_t diff = p0[ib]
1691 + p1[ib] * vd
1692 + p2[ib] * vd*vd
1693 + p3[ib] * vd*vd*vd;
1694
1695 return diff;
1696
1697}
1698
1699//_____________________________________________________________________________
1700Float_t AliTRDdigitizer::GetDiffusionT(Float_t vd, Float_t b)
1701{
1702 //
1703 // Returns the transverse diffusion coefficient for a given drift
1704 // velocity <vd> and a B-field <b> for Xe/CO2 (15%).
1705 // The values are according to a GARFIELD simulation.
1706 //
1707
1708 const Int_t kNb = 5;
1709 Float_t p0[kNb] = { 0.009550, 0.009599, 0.009674, 0.009757, 0.009850 };
1710 Float_t p1[kNb] = { 0.006667, 0.006539, 0.006359, 0.006153, 0.005925 };
1711 Float_t p2[kNb] = { -0.000853, -0.000798, -0.000721, -0.000635, -0.000541 };
1712 Float_t p3[kNb] = { 0.000131, 0.000122, 0.000111, 0.000098, 0.000085 };
1713
1714 Int_t ib = ((Int_t) (10 * (b - 0.15)));
1715 ib = TMath::Max( 0,ib);
1716 ib = TMath::Min(kNb,ib);
1717
1718 Float_t diff = p0[ib]
1719 + p1[ib] * vd
1720 + p2[ib] * vd*vd
1721 + p3[ib] * vd*vd*vd;
1722
1723 return diff;
1724
1725}
1726
1727//_____________________________________________________________________________
1728Float_t AliTRDdigitizer::GetOmegaTau(Float_t vd, Float_t b)
1729{
1730 //
1731 // Returns omega*tau (tan(Lorentz-angle)) for a given drift velocity <vd>
1732 // and a B-field <b> for Xe/CO2 (15%).
1733 // The values are according to a GARFIELD simulation.
1734 //
1735
1736 const Int_t kNb = 5;
1737 Float_t p0[kNb] = { 0.004810, 0.007412, 0.010252, 0.013409, 0.016888 };
1738 Float_t p1[kNb] = { 0.054875, 0.081534, 0.107333, 0.131983, 0.155455 };
1739 Float_t p2[kNb] = { -0.008682, -0.012896, -0.016987, -0.020880, -0.024623 };
1740 Float_t p3[kNb] = { 0.000155, 0.000238, 0.000330, 0.000428, 0.000541 };
1741
1742 Int_t ib = ((Int_t) (10 * (b - 0.15)));
1743 ib = TMath::Max( 0,ib);
1744 ib = TMath::Min(kNb,ib);
1745
1746 Float_t alphaL = p0[ib]
1747 + p1[ib] * vd
1748 + p2[ib] * vd*vd
1749 + p3[ib] * vd*vd*vd;
1750
1751 return TMath::Tan(alphaL);
793ff80c 1752
1753}
1754