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4c039060 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15
16/*
17$Log$
036da493 18Revision 1.14 1999/11/02 17:15:54 fca
19Correct ansi scoping not accepted by HP compilers
20
0549c011 21Revision 1.13 1999/11/02 17:14:51 fca
22Correct ansi scoping not accepted by HP compilers
23
9c767df4 24Revision 1.12 1999/11/02 16:35:56 fca
25New version of TRD introduced
26
5c7f4665 27Revision 1.11 1999/11/01 20:41:51 fca
28Added protections against using the wrong version of FRAME
29
ab76897d 30Revision 1.10 1999/09/29 09:24:35 fca
31Introduction of the Copyright and cvs Log
32
4c039060 33*/
34
fe4da5cc 35///////////////////////////////////////////////////////////////////////////////
36// //
5c7f4665 37// Transition Radiation Detector version 2 -- slow simulator //
fe4da5cc 38// //
39//Begin_Html
40/*
5c7f4665 41<img src="picts/AliTRDfullClass.gif">
fe4da5cc 42*/
43//End_Html
44// //
45// //
46///////////////////////////////////////////////////////////////////////////////
47
48#include <TMath.h>
fe4da5cc 49#include <TVector.h>
5c7f4665 50#include <TRandom.h>
fe4da5cc 51
fe4da5cc 52#include "AliTRDv1.h"
5c7f4665 53#include "AliTRDmatrix.h"
fe4da5cc 54#include "AliRun.h"
fe4da5cc 55#include "AliMC.h"
d3f347ff 56#include "AliConst.h"
5c7f4665 57
fe4da5cc 58ClassImp(AliTRDv1)
59
60//_____________________________________________________________________________
61AliTRDv1::AliTRDv1(const char *name, const char *title)
62 :AliTRD(name, title)
63{
64 //
5c7f4665 65 // Standard constructor for Transition Radiation Detector version 2
fe4da5cc 66 //
82bbf98a 67
5c7f4665 68 fIdSens = 0;
69
70 fIdChamber1 = 0;
71 fIdChamber2 = 0;
72 fIdChamber3 = 0;
73
74 fSensSelect = 0;
75 fSensPlane = 0;
76 fSensChamber = 0;
77 fSensSector = 0;
82bbf98a 78
5c7f4665 79 fGasGain = 0;
80 fNoise = 0;
81 fChipGain = 0;
82 fADCoutRange = 0;
83 fADCinRange = 0;
84 fADCthreshold = 0;
85
86 fDiffusionT = 0;
87 fDiffusionL = 0;
88
89 fClusMaxThresh = 0;
90 fClusSigThresh = 0;
91 fClusMethod = 0;
92
93 fDeltaE = NULL;
94
95 SetBufferSize(128000);
96
97}
98
99//_____________________________________________________________________________
100AliTRDv1::~AliTRDv1()
101{
82bbf98a 102
5c7f4665 103 if (fDeltaE) delete fDeltaE;
82bbf98a 104
fe4da5cc 105}
106
107//_____________________________________________________________________________
108void AliTRDv1::CreateGeometry()
109{
110 //
5c7f4665 111 // Create the GEANT geometry for the Transition Radiation Detector - Version 2
112 // This version covers the full azimuth.
d3f347ff 113 //
114
82bbf98a 115 // Check that FRAME is there otherwise we have no place where to put the TRD
116 AliModule* FRAME = gAlice->GetModule("FRAME");
117 if (!FRAME) return;
d3f347ff 118
82bbf98a 119 // Define the chambers
120 AliTRD::CreateGeometry();
d3f347ff 121
fe4da5cc 122}
123
124//_____________________________________________________________________________
125void AliTRDv1::CreateMaterials()
126{
127 //
5c7f4665 128 // Create materials for the Transition Radiation Detector version 2
fe4da5cc 129 //
82bbf98a 130
d3f347ff 131 AliTRD::CreateMaterials();
82bbf98a 132
fe4da5cc 133}
134
135//_____________________________________________________________________________
5c7f4665 136void AliTRDv1::Diffusion(Float_t driftlength, Float_t *xyz)
fe4da5cc 137{
138 //
5c7f4665 139 // Applies the diffusion smearing to the position of a single electron
fe4da5cc 140 //
82bbf98a 141
5c7f4665 142 if ((driftlength > 0) &&
143 (driftlength < kDrThick)) {
144 Float_t driftSqrt = TMath::Sqrt(driftlength);
145 Float_t sigmaT = driftSqrt * fDiffusionT;
146 Float_t sigmaL = driftSqrt * fDiffusionL;
147 xyz[0] = gRandom->Gaus(xyz[0], sigmaL);
148 xyz[1] = gRandom->Gaus(xyz[1], sigmaT);
149 xyz[2] = gRandom->Gaus(xyz[2], sigmaT);
150 }
151 else {
152 xyz[0] = 0.0;
153 xyz[1] = 0.0;
154 xyz[2] = 0.0;
155 }
ab76897d 156
5c7f4665 157}
82bbf98a 158
5c7f4665 159//_____________________________________________________________________________
160void AliTRDv1::Hits2Digits()
161{
162 //
163 // Creates TRD digits from hits. This procedure includes the following:
164 // - Diffusion
165 // - Gas gain including fluctuations
166 // - Pad-response (simple Gaussian approximation)
167 // - Electronics noise
168 // - Electronics gain
169 // - Digitization
170 // - ADC threshold
171 // The corresponding parameter can be adjusted via the various Set-functions.
172 // If these parameters are not explicitly set, default values are used (see
173 // Init-function).
174 // To produce digits from a root-file with TRD-hits use the
175 // slowDigitsCreate.C macro.
ab76897d 176 //
5c7f4665 177
178 printf("AliTRDv1::Hits2Digits -- Start creating digits\n");
179
180 ///////////////////////////////////////////////////////////////
181 // Parameter
182 ///////////////////////////////////////////////////////////////
183
184 // Converts number of electrons to fC
185 const Float_t el2fC = 1.602E-19 * 1.0E15;
186
187 ///////////////////////////////////////////////////////////////
188
189 Int_t nBytes = 0;
190
9c767df4 191 Int_t iRow;
192
5c7f4665 193 AliTRDhit *TRDhit;
194
195 // Get the pointer to the hit tree
196 TTree *HitTree = gAlice->TreeH();
197 // Get the pointer to the digits tree
198 TTree *DigitsTree = gAlice->TreeD();
199
200 // Get the number of entries in the hit tree
201 // (Number of primary particles creating a hit somewhere)
202 Int_t nTrack = (Int_t) HitTree->GetEntries();
203
204 Int_t chamBeg = 0;
205 Int_t chamEnd = kNcham;
206 if (fSensChamber) chamEnd = chamBeg = fSensChamber;
207 Int_t planBeg = 0;
208 Int_t planEnd = kNplan;
209 if (fSensPlane) planEnd = planBeg = fSensPlane;
210 Int_t sectBeg = 0;
211 Int_t sectEnd = kNsect;
212 if (fSensSector) sectEnd = sectBeg = fSensSector;
213
214 // Loop through all the chambers
215 for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
216 for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
217 for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
218
219 Int_t nDigits = 0;
220
221 printf("AliTRDv1::Hits2Digits -- Digitizing chamber %d, plane %d, sector %d\n"
222 ,icham+1,iplan+1,isect+1);
223
224 // Create a detector matrix to keep the signal and track numbers
225 AliTRDmatrix *matrix = new AliTRDmatrix(fRowMax[iplan][icham][isect]
226 ,fColMax[iplan]
227 ,fTimeMax
228 ,isect+1,icham+1,iplan+1);
229
230 // Loop through all entries in the tree
231 for (Int_t iTrack = 0; iTrack < nTrack; iTrack++) {
232
233 gAlice->ResetHits();
234 nBytes += HitTree->GetEvent(iTrack);
235
236 // Get the number of hits in the TRD created by this particle
237 Int_t nHit = fHits->GetEntriesFast();
238
239 // Loop through the TRD hits
240 for (Int_t iHit = 0; iHit < nHit; iHit++) {
241
242 if (!(TRDhit = (AliTRDhit *) fHits->UncheckedAt(iHit)))
243 continue;
244
245 Float_t x = TRDhit->fX;
246 Float_t y = TRDhit->fY;
247 Float_t z = TRDhit->fZ;
248 Float_t q = TRDhit->fQ;
249 Int_t track = TRDhit->fTrack;
250 Int_t plane = TRDhit->fPlane;
251 Int_t sector = TRDhit->fSector;
252 Int_t chamber = TRDhit->fChamber;
253
254 if ((sector != isect+1) ||
255 (plane != iplan+1) ||
256 (chamber != icham+1))
257 continue;
258
259 // Rotate the sectors on top of each other
260 Float_t phi = 2.0 * kPI / (Float_t) kNsect
261 * ((Float_t) sector - 0.5);
262 Float_t xRot = -x * TMath::Cos(phi) + y * TMath::Sin(phi);
263 Float_t yRot = x * TMath::Sin(phi) + y * TMath::Cos(phi);
264 Float_t zRot = z;
265
266 // The hit position in pad coordinates (center pad)
267 // The pad row (z-direction)
268 Int_t rowH = (Int_t) ((zRot - fRow0[iplan][icham][isect]) / fRowPadSize);
269 // The pad column (rphi-direction)
270 Int_t colH = (Int_t) ((yRot - fCol0[iplan] ) / fColPadSize);
271 // The time bucket
272 Int_t timeH = (Int_t) ((xRot - fTime0[iplan] ) / fTimeBinSize);
273
274 // Array to sum up the signal in a box surrounding the
275 // hit postition
276 const Int_t timeBox = 5;
277 const Int_t colBox = 7;
278 const Int_t rowBox = 5;
279 Float_t signalSum[rowBox][colBox][timeBox];
9c767df4 280 for (iRow = 0; iRow < rowBox; iRow++ ) {
5c7f4665 281 for (Int_t iCol = 0; iCol < colBox; iCol++ ) {
282 for (Int_t iTime = 0; iTime < timeBox; iTime++) {
283 signalSum[iRow][iCol][iTime] = 0;
284 }
285 }
286 }
287
288 // Loop over all electrons of this hit
289 Int_t nEl = (Int_t) q;
290 for (Int_t iEl = 0; iEl < nEl; iEl++) {
291
292 // Apply the diffusion smearing
293 Float_t driftlength = xRot - fTime0[iplan];
294 Float_t xyz[3];
295 xyz[0] = xRot;
296 xyz[1] = yRot;
297 xyz[2] = zRot;
298 Diffusion(driftlength,xyz);
299
300 // At this point absorption effects that depend on the
301 // driftlength could be taken into account.
302
303 // The electron position and the distance to the hit position
304 // in pad units
305 // The pad row (z-direction)
306 Int_t rowE = (Int_t) ((xyz[2] - fRow0[iplan][icham][isect]) / fRowPadSize);
307 Int_t rowD = rowH - rowE;
308 // The pad column (rphi-direction)
309 Int_t colE = (Int_t) ((xyz[1] - fCol0[iplan] ) / fColPadSize);
310 Int_t colD = colH - colE;
311 // The time bucket
312 Int_t timeE = (Int_t) ((xyz[0] - fTime0[iplan] ) / fTimeBinSize);
313 Int_t timeD = timeH - timeE;
314
315 // Apply the gas gain including fluctuations
316 Int_t signal = (Int_t) (-fGasGain * TMath::Log(gRandom->Rndm()));
317
318 // The distance of the electron to the center of the pad
319 // in units of pad width
320 Float_t dist = (xyz[1] - fCol0[iplan] - (colE + 0.5) * fColPadSize)
321 / fColPadSize;
322
323 // Sum up the signal in the different pixels
324 // and apply the pad response
325 Int_t rowIdx = rowD + (Int_t) ( rowBox / 2);
326 Int_t colIdx = colD + (Int_t) ( colBox / 2);
327 Int_t timeIdx = timeD + (Int_t) (timeBox / 2);
328 signalSum[rowIdx][colIdx-1][timeIdx] += PadResponse(dist-1.) * signal;
329 signalSum[rowIdx][colIdx ][timeIdx] += PadResponse(dist ) * signal;
330 signalSum[rowIdx][colIdx+1][timeIdx] += PadResponse(dist+1.) * signal;
331
332 }
333
334 // Add the padcluster to the detector matrix
9c767df4 335 for (iRow = 0; iRow < rowBox; iRow++ ) {
5c7f4665 336 for (Int_t iCol = 0; iCol < colBox; iCol++ ) {
337 for (Int_t iTime = 0; iTime < timeBox; iTime++) {
338
339 Int_t rowB = rowH + iRow - (Int_t) ( rowBox / 2);
340 Int_t colB = colH + iCol - (Int_t) ( colBox / 2);
341 Int_t timeB = timeH + iTime - (Int_t) (timeBox / 2);
342
343 Float_t signalB = signalSum[iRow][iCol][iTime];
344 if (signalB > 0.0) {
345 matrix->AddSignal(rowB,colB,timeB,signalB);
346 if (!(matrix->AddTrack(rowB,colB,timeB,track)))
347 printf(" More than three tracks in a pixel!\n");
348 }
349
350 }
351 }
352 }
353
354 }
355
356 }
357
358 // Create the hits for this chamber
359 for (Int_t iRow = 0; iRow < fRowMax[iplan][icham][isect]; iRow++ ) {
360 for (Int_t iCol = 0; iCol < fColMax[iplan] ; iCol++ ) {
361 for (Int_t iTime = 0; iTime < fTimeMax ; iTime++) {
362
363 Float_t signalAmp = matrix->GetSignal(iRow,iCol,iTime);
364
365 // Add the noise
366 signalAmp = TMath::Max(gRandom->Gaus(signalAmp,fNoise),(Float_t) 0.0);
367 // Convert to fC
368 signalAmp *= el2fC;
369 // Convert to mV
370 signalAmp *= fChipGain;
371 // Convert to ADC counts
372 Int_t adc = (Int_t) (signalAmp * (fADCoutRange / fADCinRange));
373
374 // Apply threshold on ADC value
375 if (adc > fADCthreshold) {
376
377 Int_t trackSave[3];
378 for (Int_t ii = 0; ii < 3; ii++) {
379 trackSave[ii] = matrix->GetTrack(iRow,iCol,iTime,ii);
380 }
381
382 Int_t digits[7];
383 digits[0] = matrix->GetSector();
384 digits[1] = matrix->GetChamber();
385 digits[2] = matrix->GetPlane();
386 digits[3] = iRow;
387 digits[4] = iCol;
388 digits[5] = iTime;
389 digits[6] = adc;
390
391 // Add this digit to the TClonesArray
392 AddDigit(trackSave,digits);
393 nDigits++;
394
395 }
396
397 }
398 }
399 }
400
401 printf("AliTRDv1::Hits2Digits -- Number of digits found: %d\n",nDigits);
402
403 // Clean up
404 delete matrix;
405
406 }
ab76897d 407 }
5c7f4665 408 }
ab76897d 409
5c7f4665 410 // Fill the digits-tree
411 printf("AliTRDv1::Hits2Digits -- Fill the digits tree\n");
412 DigitsTree->Fill();
413
414}
415
416//_____________________________________________________________________________
417void AliTRDv1::Digits2Clusters()
418{
419
420 //
421 // Method to convert AliTRDdigits created by AliTRDv1::Hits2Digits()
422 // into AliTRDclusters
423 // To produce cluster from a root-file with TRD-digits use the
424 // slowClusterCreate.C macro.
425 //
9c767df4 426
0549c011 427 Int_t row;
5c7f4665 428
429 printf("AliTRDv1::Digits2Clusters -- Start creating clusters\n");
430
431 AliTRDdigit *TRDdigit;
432 TClonesArray *TRDDigits;
433
434 // Parameters
435 Float_t maxThresh = fClusMaxThresh; // threshold value for maximum
436 Float_t signalThresh = fClusSigThresh; // threshold value for digit signal
437 Int_t clusteringMethod = fClusMethod; // clustering method option (for testing)
438
439 const Float_t epsilon = 0.01; // iteration limit for unfolding procedure
440
441 // Get the pointer to the digits tree
442 TTree *DigitTree = gAlice->TreeD();
443 // Get the pointer to the cluster tree
444 TTree *ClusterTree = gAlice->TreeD();
445
446 // Get the pointer to the digits container
447 TRDDigits = Digits();
448
449 Int_t chamBeg = 0;
450 Int_t chamEnd = kNcham;
451 if (fSensChamber) chamEnd = chamBeg = fSensChamber;
452 Int_t planBeg = 0;
453 Int_t planEnd = kNplan;
454 if (fSensPlane) planEnd = planBeg = fSensPlane;
455 Int_t sectBeg = 0;
456 Int_t sectEnd = kNsect;
457 if (fSensSector) sectEnd = sectBeg = fSensSector;
458
459 // Import the digit tree
460 gAlice->ResetDigits();
036da493 461 Int_t nbytes=0;
5c7f4665 462 nbytes += DigitTree->GetEvent(1);
463
464 // Get the number of digits in the detector
465 Int_t nTRDDigits = TRDDigits->GetEntriesFast();
466
467 // *** Start clustering *** in every chamber
468 for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
469 for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
470 for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
471
472 Int_t nClusters = 0;
473 printf("AliTRDv1::Digits2Clusters -- Finding clusters in chamber %d, plane %d, sector %d\n"
474 ,icham+1,iplan+1,isect+1);
475
476 // Create a detector matrix to keep maxima
477 AliTRDmatrix *digitMatrix = new AliTRDmatrix(fRowMax[iplan][icham][isect]
478 ,fColMax[iplan]
479 ,fTimeMax,isect+1
480 ,icham+1,iplan+1);
481 // Create a matrix to contain maximum flags
482 AliTRDmatrix *maximaMatrix = new AliTRDmatrix(fRowMax[iplan][icham][isect]
483 ,fColMax[iplan]
484 ,fTimeMax
485 ,isect+1,icham+1,iplan+1);
486
487 // Loop through all TRD digits
488 for (Int_t iTRDDigits = 0; iTRDDigits < nTRDDigits; iTRDDigits++) {
489
490 // Get the information for this digit
491 TRDdigit = (AliTRDdigit*) TRDDigits->UncheckedAt(iTRDDigits);
492 Int_t signal = TRDdigit->fSignal;
493 Int_t sector = TRDdigit->fSector;
494 Int_t chamber = TRDdigit->fChamber;
495 Int_t plane = TRDdigit->fPlane;
496 Int_t row = TRDdigit->fRow;
497 Int_t col = TRDdigit->fCol;
498 Int_t time = TRDdigit->fTime;
499
500 Int_t track[3];
501 for (Int_t iTrack = 0; iTrack < 3; iTrack++) {
502 track[iTrack] = TRDdigit->AliDigit::fTracks[iTrack];
503 }
504
505 if ((sector != isect+1) ||
506 (plane != iplan+1) ||
507 (chamber != icham+1))
508 continue;
509
510 // Fill the detector matrix
511 if (signal > signalThresh) {
512 digitMatrix->SetSignal(row,col,time,signal);
513 for (Int_t iTrack = 0; iTrack < 3; iTrack++) {
514 if (track[iTrack] > 0) {
515 digitMatrix->AddTrack(row,col,time,track[iTrack]);
516 }
517 }
518 }
519
520 }
521
522 // Loop chamber and find maxima in digitMatrix
9c767df4 523 for (row = 0; row < fRowMax[iplan][icham][isect]; row++) {
5c7f4665 524 for (Int_t col = 1; col < fColMax[iplan] ; col++) {
525 for (Int_t time = 0; time < fTimeMax ; time++) {
526
527 if (digitMatrix->GetSignal(row,col,time)
528 < digitMatrix->GetSignal(row,col - 1,time)) {
529 // really maximum?
530 if (col > 1) {
531 if (digitMatrix->GetSignal(row,col - 2,time)
532 < digitMatrix->GetSignal(row,col - 1,time)) {
533 // yes, so set maximum flag
534 maximaMatrix->SetSignal(row,col - 1,time,1);
535 }
536 else maximaMatrix->SetSignal(row,col - 1,time,0);
537 }
538 }
539
540 } // time
541 } // col
542 } // row
543
544 // now check maxima and calculate cluster position
9c767df4 545 for (row = 0; row < fRowMax[iplan][icham][isect]; row++) {
5c7f4665 546 for (Int_t col = 1; col < fColMax[iplan] ; col++) {
547 for (Int_t time = 0; time < fTimeMax ; time++) {
548
549 if ((maximaMatrix->GetSignal(row,col,time) > 0)
550 && (digitMatrix->GetSignal(row,col,time) > maxThresh)) {
551
552 Int_t clusters[5] = {0}; // cluster-object data
553
554 Float_t ratio = 0; // ratio resulting from unfolding
555 Float_t padSignal[5] = {0}; // signals on max and neighbouring pads
556 Float_t clusterSignal[3] = {0}; // signals from cluster
557 Float_t clusterPos[3] = {0}; // cluster in ALICE refFrame coords
558 Float_t clusterPads[6] = {0}; // cluster pad info
559
560 // setting values
561 clusters[0] = isect+1; // = isect ????
562 clusters[1] = icham+1; // = ichamber ????
563 clusters[2] = iplan+1; // = iplane ????
564 clusters[3] = time;
565
566 clusterPads[0] = icham+1;
567 clusterPads[1] = isect+1;
568 clusterPads[2] = iplan+1;
569
570 for (Int_t iPad = 0; iPad < 3; iPad++) {
571 clusterSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
572 }
573
574 // neighbouring maximum on right side?
575 if (col < fColMax[iplan] - 2) {
576 if (maximaMatrix->GetSignal(row,col + 2,time) > 0) {
577 for (Int_t iPad = 0; iPad < 5; iPad++) {
578 padSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
579 }
580
581 // unfold:
582 ratio = Unfold(epsilon, padSignal);
583
584 // set signal on overlapping pad to ratio
585 clusterSignal[2] *= ratio;
586 }
587 }
588
589 switch (clusteringMethod) {
590 case 1:
591 // method 1: simply center of mass
592 clusterPads[3] = row + 0.5;
593 clusterPads[4] = col - 0.5 + (clusterSignal[2] - clusterSignal[0]) /
594 (clusterSignal[1] + clusterSignal[2] + clusterSignal[3]);
595 clusterPads[5] = time + 0.5;
596
597 nClusters++;
598 break;
599 case 2:
600 // method 2: integral gauss fit on 3 pads
601 TH1F *hPadCharges = new TH1F("hPadCharges", "Charges on center 3 pads"
602 , 5, -1.5, 3.5);
603 for (Int_t iCol = -1; iCol <= 3; iCol++) {
604 if (clusterSignal[iCol] < 1) clusterSignal[iCol] = 1;
605 hPadCharges->Fill(iCol, clusterSignal[iCol]);
606 }
607 hPadCharges->Fit("gaus", "IQ", "SAME", -0.5, 2.5);
608 TF1 *fPadChargeFit = hPadCharges->GetFunction("gaus");
609 Double_t colMean = fPadChargeFit->GetParameter(1);
610
611 clusterPads[3] = row + 0.5;
612 clusterPads[4] = col - 1.5 + colMean;
613 clusterPads[5] = time + 0.5;
614
615 delete hPadCharges;
616
617 nClusters++;
618 break;
619 }
620
621 Float_t clusterCharge = clusterSignal[0]
622 + clusterSignal[1]
623 + clusterSignal[2];
624 clusters[4] = (Int_t)clusterCharge;
625
626 Int_t trackSave[3];
627 for (Int_t iTrack = 0; iTrack < 3; iTrack++) {
628 trackSave[iTrack] = digitMatrix->GetTrack(row,col,time,iTrack);
629 }
630
631 // Calculate cluster position in ALICE refFrame coords
632 // and set array clusterPos to calculated values
633 Pads2XYZ(clusterPads, clusterPos);
634
635 // Add cluster to reconstruction tree
636 AddCluster(trackSave,clusters,clusterPos);
637
638 }
82bbf98a 639
5c7f4665 640 } // time
641 } // col
642 } // row
643
644 printf("AliTRDv1::Digits2Clusters -- Number of clusters found: %d\n",nClusters);
645
646 delete digitMatrix;
647 delete maximaMatrix;
648
649 } // isect
650 } // iplan
651 } // icham
652
653 // Fill the cluster-tree
654 printf("AliTRDv1::Digits2Clusters -- Total number of clusters found: %d\n"
655 ,fClusters->GetEntries());
656 printf("AliTRDv1::Digits2Clusters -- Fill the cluster tree\n");
657 ClusterTree->Fill();
658
659}
660
661//_____________________________________________________________________________
662void AliTRDv1::Init()
663{
664 //
665 // Initialise Transition Radiation Detector after geometry has been built.
666 // Includes the default settings of all parameter for the digitization.
667 //
668
669 AliTRD::Init();
670
671 printf(" Slow simulator\n");
672 if (fSensPlane)
673 printf(" Only plane %d is sensitive\n",fSensPlane);
674 if (fSensChamber)
675 printf(" Only chamber %d is sensitive\n",fSensChamber);
676 if (fSensSector)
677 printf(" Only sector %d is sensitive\n",fSensSector);
678
679 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
680 const Float_t kPoti = 12.1;
681 // Maximum energy (50 keV);
682 const Float_t kEend = 50000.0;
683 // Ermilova distribution for the delta-ray spectrum
684 Float_t Poti = TMath::Log(kPoti);
685 Float_t Eend = TMath::Log(kEend);
686 fDeltaE = new TF1("deltae",Ermilova,Poti,Eend,0);
687
688 // Identifier of the sensitive volume (drift region)
689 fIdSens = gMC->VolId("UL05");
82bbf98a 690
691 // Identifier of the TRD-driftchambers
692 fIdChamber1 = gMC->VolId("UCIO");
693 fIdChamber2 = gMC->VolId("UCIM");
694 fIdChamber3 = gMC->VolId("UCII");
695
5c7f4665 696 // The default parameter for the digitization
697 if (!(fGasGain)) fGasGain = 2.0E3;
698 if (!(fNoise)) fNoise = 3000.;
699 if (!(fChipGain)) fChipGain = 10.;
700 if (!(fADCoutRange)) fADCoutRange = 255.;
701 if (!(fADCinRange)) fADCinRange = 2000.;
702 if (!(fADCthreshold)) fADCthreshold = 1;
703
704 // Transverse and longitudinal diffusion coefficients (Xe/Isobutane)
705 if (!(fDiffusionT)) fDiffusionT = 0.060;
706 if (!(fDiffusionL)) fDiffusionL = 0.017;
707
708 // The default parameter for the clustering
709 if (!(fClusMaxThresh)) fClusMaxThresh = 5.0;
710 if (!(fClusSigThresh)) fClusSigThresh = 2.0;
711 if (!(fClusMethod)) fClusMethod = 1;
712
713 for (Int_t i = 0; i < 80; i++) printf("*");
714 printf("\n");
715
fe4da5cc 716}
717
718//_____________________________________________________________________________
5c7f4665 719Float_t AliTRDv1::PadResponse(Float_t x)
fe4da5cc 720{
721 //
5c7f4665 722 // The pad response for the chevron pads.
723 // We use a simple Gaussian approximation which should be good
724 // enough for our purpose.
fe4da5cc 725 //
d3f347ff 726
5c7f4665 727 // The parameters for the response function
728 const Float_t aa = 0.8872;
729 const Float_t bb = -0.00573;
730 const Float_t cc = 0.454;
731 const Float_t cc2 = cc*cc;
732
733 Float_t pr = aa * (bb + TMath::Exp(-x*x / (2. * cc2)));
734
735 return (pr);
736
737}
738
739//_____________________________________________________________________________
740void AliTRDv1::SetSensPlane(Int_t iplane)
741{
742 //
743 // Defines the hit-sensitive plane (1-6)
744 //
82bbf98a 745
5c7f4665 746 if ((iplane < 0) || (iplane > 6)) {
747 printf("Wrong input value: %d\n",iplane);
748 printf("Use standard setting\n");
749 fSensPlane = 0;
750 fSensSelect = 0;
751 return;
752 }
82bbf98a 753
5c7f4665 754 fSensSelect = 1;
755 fSensPlane = iplane;
82bbf98a 756
5c7f4665 757}
758
759//_____________________________________________________________________________
760void AliTRDv1::SetSensChamber(Int_t ichamber)
761{
762 //
763 // Defines the hit-sensitive chamber (1-5)
764 //
765
766 if ((ichamber < 0) || (ichamber > 5)) {
767 printf("Wrong input value: %d\n",ichamber);
768 printf("Use standard setting\n");
769 fSensChamber = 0;
770 fSensSelect = 0;
771 return;
772 }
773
774 fSensSelect = 1;
775 fSensChamber = ichamber;
776
777}
778
779//_____________________________________________________________________________
780void AliTRDv1::SetSensSector(Int_t isector)
781{
782 //
783 // Defines the hit-sensitive sector (1-18)
784 //
785
786 if ((isector < 0) || (isector > 18)) {
787 printf("Wrong input value: %d\n",isector);
788 printf("Use standard setting\n");
789 fSensSector = 0;
790 fSensSelect = 0;
791 return;
792 }
793
794 fSensSelect = 1;
795 fSensSector = isector;
796
797}
798
799//_____________________________________________________________________________
800void AliTRDv1::StepManager()
801{
802 //
803 // Called at every step in the Transition Radiation Detector version 2.
804 // Slow simulator. Every charged track produces electron cluster as hits
805 // along its path across the drift volume. The step size is set acording
806 // to Bethe-Bloch. The energy distribution of the delta electrons follows
807 // a spectrum taken from Ermilova et al.
808 //
809
810 Int_t iIdSens, icSens;
811 Int_t iIdSpace, icSpace;
812 Int_t iIdChamber, icChamber;
813 Int_t vol[3];
814 Int_t iPid;
815
816 Float_t hits[4];
817 Float_t random[1];
818 Float_t charge;
819 Float_t aMass;
820
821 Double_t pTot;
822 Double_t qTot;
823 Double_t eDelta;
824 Double_t betaGamma, pp;
825
826 TLorentzVector pos, mom;
82bbf98a 827 TClonesArray &lhits = *fHits;
828
5c7f4665 829 const Double_t kBig = 1.0E+12;
830
831 // Ionization energy
832 const Float_t kWion = 22.04;
833 // Maximum energy for e+ e- g for the step-size calculation
834 const Float_t kPTotMax = 0.002;
835 // Plateau value of the energy-loss for electron in xenon
836 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
837 //const Double_t kPlateau = 1.70;
838 // the averaged value (26/3/99)
839 const Float_t kPlateau = 1.55;
840 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
841 const Float_t kPrim = 48.0;
842 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
843 const Float_t kPoti = 12.1;
844
845 // Set the maximum step size to a very large number for all
846 // neutral particles and those outside the driftvolume
847 gMC->SetMaxStep(kBig);
848
849 // Use only charged tracks
850 if (( gMC->TrackCharge() ) &&
851 (!gMC->IsTrackStop() ) &&
852 (!gMC->IsTrackDisappeared())) {
fe4da5cc 853
5c7f4665 854 // Inside a sensitive volume?
82bbf98a 855 iIdSens = gMC->CurrentVolID(icSens);
856 if (iIdSens == fIdSens) {
857
82bbf98a 858 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
859 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
fe4da5cc 860
5c7f4665 861 // Calculate the energy of the delta-electrons
862 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
863 eDelta = TMath::Max(eDelta,0.0);
864
865 // The number of secondary electrons created
866 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
867
868 // The hit coordinates and charge
869 gMC->TrackPosition(pos);
870 hits[0] = pos[0];
871 hits[1] = pos[1];
872 hits[2] = pos[2];
873 hits[3] = qTot;
874
fe4da5cc 875 // The sector number
5c7f4665 876 Float_t phi = pos[1] != 0 ? TMath::Atan2(pos[0],pos[1]) : (pos[0] > 0 ? 180. : 0.);
877 vol[0] = ((Int_t) (phi / 20)) + 1;
82bbf98a 878
d3f347ff 879 // The chamber number
880 // 1: outer left
82bbf98a 881 // 2: middle left
d3f347ff 882 // 3: inner
82bbf98a 883 // 4: middle right
d3f347ff 884 // 5: outer right
82bbf98a 885 if (iIdChamber == fIdChamber1)
886 vol[1] = (hits[2] < 0 ? 1 : 5);
887 else if (iIdChamber == fIdChamber2)
888 vol[1] = (hits[2] < 0 ? 2 : 4);
889 else if (iIdChamber == fIdChamber3)
d3f347ff 890 vol[1] = 3;
82bbf98a 891
fe4da5cc 892 // The plane number
82bbf98a 893 vol[2] = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6;
894
5c7f4665 895 // Check on selected volumes
896 Int_t addthishit = 1;
897 if (fSensSelect) {
898 if ((fSensPlane) && (vol[2] != fSensPlane )) addthishit = 0;
899 if ((fSensChamber) && (vol[1] != fSensChamber)) addthishit = 0;
900 if ((fSensSector) && (vol[0] != fSensSector )) addthishit = 0;
901 }
902
903 // Add this hit
904 if (addthishit) {
905
906 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack(),vol,hits);
907
908 // The energy loss according to Bethe Bloch
909 gMC->TrackMomentum(mom);
910 pTot = mom.Rho();
911 iPid = gMC->TrackPid();
912 if ( (iPid > 3) ||
913 ((iPid <= 3) && (pTot < kPTotMax))) {
914 aMass = gMC->TrackMass();
915 betaGamma = pTot / aMass;
916 pp = kPrim * BetheBloch(betaGamma);
917 // Take charge > 1 into account
918 charge = gMC->TrackCharge();
919 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
920 }
921 // Electrons above 20 Mev/c are at the plateau
922 else {
923 pp = kPrim * kPlateau;
924 }
925
926 // Calculate the maximum step size for the next tracking step
927 if (pp > 0) {
928 do
929 gMC->Rndm(random,1);
930 while ((random[0] == 1.) || (random[0] == 0.));
931 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
932 }
933
934 }
935 else {
936 // set step size to maximal value
937 gMC->SetMaxStep(kBig);
938 }
d3f347ff 939
940 }
941
5c7f4665 942 }
943
944}
945
946//_____________________________________________________________________________
947Double_t AliTRDv1::BetheBloch(Double_t bg)
948{
949 //
950 // Parametrization of the Bethe-Bloch-curve
951 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
952 //
953
954 // This parameters have been adjusted to averaged values from GEANT
955 const Double_t kP1 = 7.17960e-02;
956 const Double_t kP2 = 8.54196;
957 const Double_t kP3 = 1.38065e-06;
958 const Double_t kP4 = 5.30972;
959 const Double_t kP5 = 2.83798;
960
961 // This parameters have been adjusted to Xe-data found in:
962 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
963 //const Double_t kP1 = 0.76176E-1;
964 //const Double_t kP2 = 10.632;
965 //const Double_t kP3 = 3.17983E-6;
966 //const Double_t kP4 = 1.8631;
967 //const Double_t kP5 = 1.9479;
968
969 if (bg > 0) {
970 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
971 Double_t aa = TMath::Power(yy,kP4);
972 Double_t bb = TMath::Power((1./bg),kP5);
973 bb = TMath::Log(kP3 + bb);
974 return ((kP2 - aa - bb)*kP1 / aa);
975 }
976 else
977 return 0;
d3f347ff 978
fe4da5cc 979}
5c7f4665 980
981//_____________________________________________________________________________
982Double_t Ermilova(Double_t *x, Double_t *)
983{
984 //
985 // Calculates the delta-ray energy distribution according to Ermilova.
986 // Logarithmic scale !
987 //
988
989 Double_t energy;
990 Double_t dpos;
991 Double_t dnde;
992
993 Int_t pos1, pos2;
994
995 const Int_t nV = 31;
996
997 Float_t vxe[nV] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
998 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
999 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
1000 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
1001 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
1002 , 9.4727, 9.9035,10.3735,10.5966,10.8198
1003 ,11.5129 };
1004
1005 Float_t vye[nV] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
1006 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
1007 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
1008 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
1009 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
1010 , 0.04 , 0.023, 0.015, 0.011, 0.01
1011 , 0.004 };
1012
1013 energy = x[0];
1014
1015 // Find the position
1016 pos1 = pos2 = 0;
1017 dpos = 0;
1018 do {
1019 dpos = energy - vxe[pos2++];
1020 }
1021 while (dpos > 0);
1022 pos2--;
1023 if (pos2 > nV) pos2 = nV;
1024 pos1 = pos2 - 1;
1025
1026 // Differentiate between the sampling points
1027 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
1028
1029 return dnde;
1030
1031}
1032
1033//_____________________________________________________________________________
1034void AliTRDv1::Pads2XYZ(Float_t *pads, Float_t *pos)
1035{
1036 // Method to convert pad coordinates (row,col,time)
1037 // into ALICE reference frame coordinates (x,y,z)
1038
1039 Int_t chamber = (Int_t) pads[0]; // chamber info (1-5)
1040 Int_t sector = (Int_t) pads[1]; // sector info (1-18)
1041 Int_t plane = (Int_t) pads[2]; // plane info (1-6)
1042
1043 Int_t icham = chamber - 1; // chamber info (0-4)
1044 Int_t isect = sector - 1; // sector info (0-17)
1045 Int_t iplan = plane - 1; // plane info (0-5)
1046
1047 Float_t padRow = pads[3]; // Pad Row position
1048 Float_t padCol = pads[4]; // Pad Column position
1049 Float_t timeSlice = pads[5]; // Time "position"
1050
1051 // calculate (x,y) position in rotated chamber
1052 Float_t yRot = fCol0[iplan] + padCol * fColPadSize;
1053 Float_t xRot = fTime0[iplan] + timeSlice * fTimeBinSize;
1054 // calculate z-position:
1055 Float_t z = fRow0[iplan][icham][isect] + padRow * fRowPadSize;
1056
1057 /**
1058 rotate chamber back to original position
1059 1. mirror at y-axis, 2. rotate back to position (-phi)
1060 / cos(phi) -sin(phi) \ / -1 0 \ / -cos(phi) -sin(phi) \
1061 \ sin(phi) cos(phi) / * \ 0 1 / = \ -sin(phi) cos(phi) /
1062 **/
1063 //Float_t phi = 2*kPI / kNsect * ((Float_t) sector - 0.5);
1064 //Float_t x = -xRot * TMath::Cos(phi) - yRot * TMath::Sin(phi);
1065 //Float_t y = -xRot * TMath::Sin(phi) + yRot * TMath::Cos(phi);
1066 Float_t phi = 2*kPI / kNsect * ((Float_t) sector - 0.5);
1067 Float_t x = -xRot * TMath::Cos(phi) + yRot * TMath::Sin(phi);
1068 Float_t y = xRot * TMath::Sin(phi) + yRot * TMath::Cos(phi);
1069
1070 // Setting values
1071 pos[0] = x;
1072 pos[1] = y;
1073 pos[2] = z;
1074
1075}
1076
1077//_____________________________________________________________________________
1078Float_t AliTRDv1::Unfold(Float_t eps, Float_t* padSignal)
1079{
1080 // Method to unfold neighbouring maxima.
1081 // The charge ratio on the overlapping pad is calculated
1082 // until there is no more change within the range given by eps.
1083 // The resulting ratio is then returned to the calling method.
1084
1085 Int_t itStep = 0; // count iteration steps
1086
1087 Float_t ratio = 0.5; // start value for ratio
1088 Float_t prevRatio = 0; // store previous ratio
1089
1090 Float_t newLeftSignal[3] = {0}; // array to store left cluster signal
1091 Float_t newRightSignal[3] = {0}; // array to store right cluster signal
1092
1093 // start iteration:
1094 while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
1095
1096 itStep++;
1097 prevRatio = ratio;
1098
1099 // cluster position according to charge ratio
1100 Float_t maxLeft = (ratio*padSignal[2] - padSignal[0]) /
1101 (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
1102 Float_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2]) /
1103 ((1-ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
1104
1105 // set cluster charge ratio
1106 Float_t ampLeft = padSignal[1];
1107 Float_t ampRight = padSignal[3];
1108
1109 // apply pad response to parameters
1110 newLeftSignal[0] = ampLeft*PadResponse(-1 - maxLeft);
1111 newLeftSignal[1] = ampLeft*PadResponse( 0 - maxLeft);
1112 newLeftSignal[2] = ampLeft*PadResponse( 1 - maxLeft);
1113
1114 newRightSignal[0] = ampRight*PadResponse(-1 - maxRight);
1115 newRightSignal[1] = ampRight*PadResponse( 0 - maxRight);
1116 newRightSignal[2] = ampRight*PadResponse( 1 - maxRight);
1117
1118 // calculate new overlapping ratio
1119 ratio = newLeftSignal[2]/(newLeftSignal[2] + newRightSignal[0]);
1120
1121 }
1122
1123 return ratio;
1124
1125}
1126