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