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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$Log$
90f8d287 18Revision 1.15 1999/11/02 17:20:19 fca
19initialise nbytes before using it
20
036da493 21Revision 1.14 1999/11/02 17:15:54 fca
22Correct ansi scoping not accepted by HP compilers
23
0549c011 24Revision 1.13 1999/11/02 17:14:51 fca
25Correct ansi scoping not accepted by HP compilers
26
9c767df4 27Revision 1.12 1999/11/02 16:35:56 fca
28New version of TRD introduced
29
5c7f4665 30Revision 1.11 1999/11/01 20:41:51 fca
31Added protections against using the wrong version of FRAME
32
ab76897d 33Revision 1.10 1999/09/29 09:24:35 fca
34Introduction of the Copyright and cvs Log
35
4c039060 36*/
37
fe4da5cc 38///////////////////////////////////////////////////////////////////////////////
39// //
5c7f4665 40// Transition Radiation Detector version 2 -- slow simulator //
fe4da5cc 41// //
42//Begin_Html
43/*
5c7f4665 44<img src="picts/AliTRDfullClass.gif">
fe4da5cc 45*/
46//End_Html
47// //
48// //
49///////////////////////////////////////////////////////////////////////////////
50
51#include <TMath.h>
fe4da5cc 52#include <TVector.h>
5c7f4665 53#include <TRandom.h>
fe4da5cc 54
fe4da5cc 55#include "AliTRDv1.h"
5c7f4665 56#include "AliTRDmatrix.h"
fe4da5cc 57#include "AliRun.h"
fe4da5cc 58#include "AliMC.h"
d3f347ff 59#include "AliConst.h"
5c7f4665 60
fe4da5cc 61ClassImp(AliTRDv1)
62
63//_____________________________________________________________________________
64AliTRDv1::AliTRDv1(const char *name, const char *title)
65 :AliTRD(name, title)
66{
67 //
5c7f4665 68 // Standard constructor for Transition Radiation Detector version 2
fe4da5cc 69 //
82bbf98a 70
5c7f4665 71 fIdSens = 0;
72
73 fIdChamber1 = 0;
74 fIdChamber2 = 0;
75 fIdChamber3 = 0;
76
77 fSensSelect = 0;
78 fSensPlane = 0;
79 fSensChamber = 0;
80 fSensSector = 0;
82bbf98a 81
5c7f4665 82 fGasGain = 0;
83 fNoise = 0;
84 fChipGain = 0;
85 fADCoutRange = 0;
86 fADCinRange = 0;
87 fADCthreshold = 0;
88
89 fDiffusionT = 0;
90 fDiffusionL = 0;
91
92 fClusMaxThresh = 0;
93 fClusSigThresh = 0;
94 fClusMethod = 0;
95
96 fDeltaE = NULL;
97
98 SetBufferSize(128000);
99
100}
101
102//_____________________________________________________________________________
103AliTRDv1::~AliTRDv1()
104{
82bbf98a 105
5c7f4665 106 if (fDeltaE) delete fDeltaE;
82bbf98a 107
fe4da5cc 108}
109
110//_____________________________________________________________________________
111void AliTRDv1::CreateGeometry()
112{
113 //
5c7f4665 114 // Create the GEANT geometry for the Transition Radiation Detector - Version 2
115 // This version covers the full azimuth.
d3f347ff 116 //
117
82bbf98a 118 // Check that FRAME is there otherwise we have no place where to put the TRD
119 AliModule* FRAME = gAlice->GetModule("FRAME");
120 if (!FRAME) return;
d3f347ff 121
82bbf98a 122 // Define the chambers
123 AliTRD::CreateGeometry();
d3f347ff 124
fe4da5cc 125}
126
127//_____________________________________________________________________________
128void AliTRDv1::CreateMaterials()
129{
130 //
5c7f4665 131 // Create materials for the Transition Radiation Detector version 2
fe4da5cc 132 //
82bbf98a 133
d3f347ff 134 AliTRD::CreateMaterials();
82bbf98a 135
fe4da5cc 136}
137
138//_____________________________________________________________________________
5c7f4665 139void AliTRDv1::Diffusion(Float_t driftlength, Float_t *xyz)
fe4da5cc 140{
141 //
5c7f4665 142 // Applies the diffusion smearing to the position of a single electron
fe4da5cc 143 //
82bbf98a 144
5c7f4665 145 if ((driftlength > 0) &&
146 (driftlength < kDrThick)) {
147 Float_t driftSqrt = TMath::Sqrt(driftlength);
148 Float_t sigmaT = driftSqrt * fDiffusionT;
149 Float_t sigmaL = driftSqrt * fDiffusionL;
150 xyz[0] = gRandom->Gaus(xyz[0], sigmaL);
151 xyz[1] = gRandom->Gaus(xyz[1], sigmaT);
152 xyz[2] = gRandom->Gaus(xyz[2], sigmaT);
153 }
154 else {
155 xyz[0] = 0.0;
156 xyz[1] = 0.0;
157 xyz[2] = 0.0;
158 }
ab76897d 159
5c7f4665 160}
82bbf98a 161
5c7f4665 162//_____________________________________________________________________________
163void AliTRDv1::Hits2Digits()
164{
165 //
166 // Creates TRD digits from hits. This procedure includes the following:
167 // - Diffusion
168 // - Gas gain including fluctuations
169 // - Pad-response (simple Gaussian approximation)
170 // - Electronics noise
171 // - Electronics gain
172 // - Digitization
173 // - ADC threshold
174 // The corresponding parameter can be adjusted via the various Set-functions.
175 // If these parameters are not explicitly set, default values are used (see
176 // Init-function).
177 // To produce digits from a root-file with TRD-hits use the
178 // slowDigitsCreate.C macro.
ab76897d 179 //
5c7f4665 180
181 printf("AliTRDv1::Hits2Digits -- Start creating digits\n");
182
183 ///////////////////////////////////////////////////////////////
184 // Parameter
185 ///////////////////////////////////////////////////////////////
186
187 // Converts number of electrons to fC
188 const Float_t el2fC = 1.602E-19 * 1.0E15;
189
190 ///////////////////////////////////////////////////////////////
191
192 Int_t nBytes = 0;
193
9c767df4 194 Int_t iRow;
195
5c7f4665 196 AliTRDhit *TRDhit;
197
198 // Get the pointer to the hit tree
199 TTree *HitTree = gAlice->TreeH();
200 // Get the pointer to the digits tree
201 TTree *DigitsTree = gAlice->TreeD();
202
203 // Get the number of entries in the hit tree
204 // (Number of primary particles creating a hit somewhere)
205 Int_t nTrack = (Int_t) HitTree->GetEntries();
206
207 Int_t chamBeg = 0;
208 Int_t chamEnd = kNcham;
209 if (fSensChamber) chamEnd = chamBeg = fSensChamber;
210 Int_t planBeg = 0;
211 Int_t planEnd = kNplan;
212 if (fSensPlane) planEnd = planBeg = fSensPlane;
213 Int_t sectBeg = 0;
214 Int_t sectEnd = kNsect;
215 if (fSensSector) sectEnd = sectBeg = fSensSector;
216
217 // Loop through all the chambers
218 for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
219 for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
220 for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
221
222 Int_t nDigits = 0;
223
224 printf("AliTRDv1::Hits2Digits -- Digitizing chamber %d, plane %d, sector %d\n"
225 ,icham+1,iplan+1,isect+1);
226
227 // Create a detector matrix to keep the signal and track numbers
228 AliTRDmatrix *matrix = new AliTRDmatrix(fRowMax[iplan][icham][isect]
229 ,fColMax[iplan]
230 ,fTimeMax
231 ,isect+1,icham+1,iplan+1);
232
233 // Loop through all entries in the tree
234 for (Int_t iTrack = 0; iTrack < nTrack; iTrack++) {
235
236 gAlice->ResetHits();
237 nBytes += HitTree->GetEvent(iTrack);
238
239 // Get the number of hits in the TRD created by this particle
240 Int_t nHit = fHits->GetEntriesFast();
241
242 // Loop through the TRD hits
243 for (Int_t iHit = 0; iHit < nHit; iHit++) {
244
245 if (!(TRDhit = (AliTRDhit *) fHits->UncheckedAt(iHit)))
246 continue;
247
248 Float_t x = TRDhit->fX;
249 Float_t y = TRDhit->fY;
250 Float_t z = TRDhit->fZ;
251 Float_t q = TRDhit->fQ;
252 Int_t track = TRDhit->fTrack;
253 Int_t plane = TRDhit->fPlane;
254 Int_t sector = TRDhit->fSector;
255 Int_t chamber = TRDhit->fChamber;
256
257 if ((sector != isect+1) ||
258 (plane != iplan+1) ||
259 (chamber != icham+1))
260 continue;
261
262 // Rotate the sectors on top of each other
263 Float_t phi = 2.0 * kPI / (Float_t) kNsect
264 * ((Float_t) sector - 0.5);
265 Float_t xRot = -x * TMath::Cos(phi) + y * TMath::Sin(phi);
266 Float_t yRot = x * TMath::Sin(phi) + y * TMath::Cos(phi);
267 Float_t zRot = z;
268
269 // The hit position in pad coordinates (center pad)
270 // The pad row (z-direction)
271 Int_t rowH = (Int_t) ((zRot - fRow0[iplan][icham][isect]) / fRowPadSize);
272 // The pad column (rphi-direction)
273 Int_t colH = (Int_t) ((yRot - fCol0[iplan] ) / fColPadSize);
274 // The time bucket
275 Int_t timeH = (Int_t) ((xRot - fTime0[iplan] ) / fTimeBinSize);
276
277 // Array to sum up the signal in a box surrounding the
278 // hit postition
279 const Int_t timeBox = 5;
280 const Int_t colBox = 7;
281 const Int_t rowBox = 5;
282 Float_t signalSum[rowBox][colBox][timeBox];
9c767df4 283 for (iRow = 0; iRow < rowBox; iRow++ ) {
5c7f4665 284 for (Int_t iCol = 0; iCol < colBox; iCol++ ) {
285 for (Int_t iTime = 0; iTime < timeBox; iTime++) {
286 signalSum[iRow][iCol][iTime] = 0;
287 }
288 }
289 }
290
291 // Loop over all electrons of this hit
292 Int_t nEl = (Int_t) q;
293 for (Int_t iEl = 0; iEl < nEl; iEl++) {
294
295 // Apply the diffusion smearing
296 Float_t driftlength = xRot - fTime0[iplan];
297 Float_t xyz[3];
298 xyz[0] = xRot;
299 xyz[1] = yRot;
300 xyz[2] = zRot;
301 Diffusion(driftlength,xyz);
302
303 // At this point absorption effects that depend on the
304 // driftlength could be taken into account.
305
306 // The electron position and the distance to the hit position
307 // in pad units
308 // The pad row (z-direction)
309 Int_t rowE = (Int_t) ((xyz[2] - fRow0[iplan][icham][isect]) / fRowPadSize);
310 Int_t rowD = rowH - rowE;
311 // The pad column (rphi-direction)
312 Int_t colE = (Int_t) ((xyz[1] - fCol0[iplan] ) / fColPadSize);
313 Int_t colD = colH - colE;
314 // The time bucket
315 Int_t timeE = (Int_t) ((xyz[0] - fTime0[iplan] ) / fTimeBinSize);
316 Int_t timeD = timeH - timeE;
317
318 // Apply the gas gain including fluctuations
319 Int_t signal = (Int_t) (-fGasGain * TMath::Log(gRandom->Rndm()));
320
321 // The distance of the electron to the center of the pad
322 // in units of pad width
323 Float_t dist = (xyz[1] - fCol0[iplan] - (colE + 0.5) * fColPadSize)
324 / fColPadSize;
325
326 // Sum up the signal in the different pixels
327 // and apply the pad response
328 Int_t rowIdx = rowD + (Int_t) ( rowBox / 2);
329 Int_t colIdx = colD + (Int_t) ( colBox / 2);
330 Int_t timeIdx = timeD + (Int_t) (timeBox / 2);
331 signalSum[rowIdx][colIdx-1][timeIdx] += PadResponse(dist-1.) * signal;
332 signalSum[rowIdx][colIdx ][timeIdx] += PadResponse(dist ) * signal;
333 signalSum[rowIdx][colIdx+1][timeIdx] += PadResponse(dist+1.) * signal;
334
335 }
336
337 // Add the padcluster to the detector matrix
9c767df4 338 for (iRow = 0; iRow < rowBox; iRow++ ) {
5c7f4665 339 for (Int_t iCol = 0; iCol < colBox; iCol++ ) {
340 for (Int_t iTime = 0; iTime < timeBox; iTime++) {
341
342 Int_t rowB = rowH + iRow - (Int_t) ( rowBox / 2);
343 Int_t colB = colH + iCol - (Int_t) ( colBox / 2);
344 Int_t timeB = timeH + iTime - (Int_t) (timeBox / 2);
345
346 Float_t signalB = signalSum[iRow][iCol][iTime];
347 if (signalB > 0.0) {
348 matrix->AddSignal(rowB,colB,timeB,signalB);
349 if (!(matrix->AddTrack(rowB,colB,timeB,track)))
350 printf(" More than three tracks in a pixel!\n");
351 }
352
353 }
354 }
355 }
356
357 }
358
359 }
360
361 // Create the hits for this chamber
362 for (Int_t iRow = 0; iRow < fRowMax[iplan][icham][isect]; iRow++ ) {
363 for (Int_t iCol = 0; iCol < fColMax[iplan] ; iCol++ ) {
364 for (Int_t iTime = 0; iTime < fTimeMax ; iTime++) {
365
366 Float_t signalAmp = matrix->GetSignal(iRow,iCol,iTime);
367
368 // Add the noise
369 signalAmp = TMath::Max(gRandom->Gaus(signalAmp,fNoise),(Float_t) 0.0);
370 // Convert to fC
371 signalAmp *= el2fC;
372 // Convert to mV
373 signalAmp *= fChipGain;
374 // Convert to ADC counts
375 Int_t adc = (Int_t) (signalAmp * (fADCoutRange / fADCinRange));
376
377 // Apply threshold on ADC value
378 if (adc > fADCthreshold) {
379
380 Int_t trackSave[3];
381 for (Int_t ii = 0; ii < 3; ii++) {
382 trackSave[ii] = matrix->GetTrack(iRow,iCol,iTime,ii);
383 }
384
385 Int_t digits[7];
386 digits[0] = matrix->GetSector();
387 digits[1] = matrix->GetChamber();
388 digits[2] = matrix->GetPlane();
389 digits[3] = iRow;
390 digits[4] = iCol;
391 digits[5] = iTime;
392 digits[6] = adc;
393
394 // Add this digit to the TClonesArray
395 AddDigit(trackSave,digits);
396 nDigits++;
397
398 }
399
400 }
401 }
402 }
403
404 printf("AliTRDv1::Hits2Digits -- Number of digits found: %d\n",nDigits);
405
406 // Clean up
407 delete matrix;
408
409 }
ab76897d 410 }
5c7f4665 411 }
ab76897d 412
5c7f4665 413 // Fill the digits-tree
414 printf("AliTRDv1::Hits2Digits -- Fill the digits tree\n");
415 DigitsTree->Fill();
416
417}
418
419//_____________________________________________________________________________
420void AliTRDv1::Digits2Clusters()
421{
422
423 //
424 // Method to convert AliTRDdigits created by AliTRDv1::Hits2Digits()
425 // into AliTRDclusters
426 // To produce cluster from a root-file with TRD-digits use the
427 // slowClusterCreate.C macro.
428 //
9c767df4 429
0549c011 430 Int_t row;
5c7f4665 431
432 printf("AliTRDv1::Digits2Clusters -- Start creating clusters\n");
433
434 AliTRDdigit *TRDdigit;
435 TClonesArray *TRDDigits;
436
437 // Parameters
438 Float_t maxThresh = fClusMaxThresh; // threshold value for maximum
439 Float_t signalThresh = fClusSigThresh; // threshold value for digit signal
440 Int_t clusteringMethod = fClusMethod; // clustering method option (for testing)
441
442 const Float_t epsilon = 0.01; // iteration limit for unfolding procedure
443
444 // Get the pointer to the digits tree
445 TTree *DigitTree = gAlice->TreeD();
446 // Get the pointer to the cluster tree
447 TTree *ClusterTree = gAlice->TreeD();
448
449 // Get the pointer to the digits container
450 TRDDigits = Digits();
451
452 Int_t chamBeg = 0;
453 Int_t chamEnd = kNcham;
454 if (fSensChamber) chamEnd = chamBeg = fSensChamber;
455 Int_t planBeg = 0;
456 Int_t planEnd = kNplan;
457 if (fSensPlane) planEnd = planBeg = fSensPlane;
458 Int_t sectBeg = 0;
459 Int_t sectEnd = kNsect;
460 if (fSensSector) sectEnd = sectBeg = fSensSector;
461
462 // Import the digit tree
463 gAlice->ResetDigits();
036da493 464 Int_t nbytes=0;
5c7f4665 465 nbytes += DigitTree->GetEvent(1);
466
467 // Get the number of digits in the detector
468 Int_t nTRDDigits = TRDDigits->GetEntriesFast();
469
470 // *** Start clustering *** in every chamber
471 for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
472 for (Int_t iplan = planBeg; iplan < planEnd; iplan++) {
473 for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
474
475 Int_t nClusters = 0;
476 printf("AliTRDv1::Digits2Clusters -- Finding clusters in chamber %d, plane %d, sector %d\n"
477 ,icham+1,iplan+1,isect+1);
478
479 // Create a detector matrix to keep maxima
480 AliTRDmatrix *digitMatrix = new AliTRDmatrix(fRowMax[iplan][icham][isect]
481 ,fColMax[iplan]
482 ,fTimeMax,isect+1
483 ,icham+1,iplan+1);
484 // Create a matrix to contain maximum flags
485 AliTRDmatrix *maximaMatrix = new AliTRDmatrix(fRowMax[iplan][icham][isect]
486 ,fColMax[iplan]
487 ,fTimeMax
488 ,isect+1,icham+1,iplan+1);
489
490 // Loop through all TRD digits
491 for (Int_t iTRDDigits = 0; iTRDDigits < nTRDDigits; iTRDDigits++) {
492
493 // Get the information for this digit
494 TRDdigit = (AliTRDdigit*) TRDDigits->UncheckedAt(iTRDDigits);
495 Int_t signal = TRDdigit->fSignal;
496 Int_t sector = TRDdigit->fSector;
497 Int_t chamber = TRDdigit->fChamber;
498 Int_t plane = TRDdigit->fPlane;
499 Int_t row = TRDdigit->fRow;
500 Int_t col = TRDdigit->fCol;
501 Int_t time = TRDdigit->fTime;
502
503 Int_t track[3];
504 for (Int_t iTrack = 0; iTrack < 3; iTrack++) {
505 track[iTrack] = TRDdigit->AliDigit::fTracks[iTrack];
506 }
507
508 if ((sector != isect+1) ||
509 (plane != iplan+1) ||
510 (chamber != icham+1))
511 continue;
512
513 // Fill the detector matrix
514 if (signal > signalThresh) {
515 digitMatrix->SetSignal(row,col,time,signal);
516 for (Int_t iTrack = 0; iTrack < 3; iTrack++) {
517 if (track[iTrack] > 0) {
518 digitMatrix->AddTrack(row,col,time,track[iTrack]);
519 }
520 }
521 }
522
523 }
524
525 // Loop chamber and find maxima in digitMatrix
9c767df4 526 for (row = 0; row < fRowMax[iplan][icham][isect]; row++) {
5c7f4665 527 for (Int_t col = 1; col < fColMax[iplan] ; col++) {
528 for (Int_t time = 0; time < fTimeMax ; time++) {
529
530 if (digitMatrix->GetSignal(row,col,time)
531 < digitMatrix->GetSignal(row,col - 1,time)) {
532 // really maximum?
533 if (col > 1) {
534 if (digitMatrix->GetSignal(row,col - 2,time)
535 < digitMatrix->GetSignal(row,col - 1,time)) {
536 // yes, so set maximum flag
537 maximaMatrix->SetSignal(row,col - 1,time,1);
538 }
539 else maximaMatrix->SetSignal(row,col - 1,time,0);
540 }
541 }
542
543 } // time
544 } // col
545 } // row
546
547 // now check maxima and calculate cluster position
9c767df4 548 for (row = 0; row < fRowMax[iplan][icham][isect]; row++) {
5c7f4665 549 for (Int_t col = 1; col < fColMax[iplan] ; col++) {
550 for (Int_t time = 0; time < fTimeMax ; time++) {
551
552 if ((maximaMatrix->GetSignal(row,col,time) > 0)
553 && (digitMatrix->GetSignal(row,col,time) > maxThresh)) {
554
555 Int_t clusters[5] = {0}; // cluster-object data
556
557 Float_t ratio = 0; // ratio resulting from unfolding
558 Float_t padSignal[5] = {0}; // signals on max and neighbouring pads
559 Float_t clusterSignal[3] = {0}; // signals from cluster
560 Float_t clusterPos[3] = {0}; // cluster in ALICE refFrame coords
561 Float_t clusterPads[6] = {0}; // cluster pad info
562
563 // setting values
564 clusters[0] = isect+1; // = isect ????
565 clusters[1] = icham+1; // = ichamber ????
566 clusters[2] = iplan+1; // = iplane ????
567 clusters[3] = time;
568
569 clusterPads[0] = icham+1;
570 clusterPads[1] = isect+1;
571 clusterPads[2] = iplan+1;
572
573 for (Int_t iPad = 0; iPad < 3; iPad++) {
574 clusterSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
575 }
576
577 // neighbouring maximum on right side?
578 if (col < fColMax[iplan] - 2) {
579 if (maximaMatrix->GetSignal(row,col + 2,time) > 0) {
580 for (Int_t iPad = 0; iPad < 5; iPad++) {
581 padSignal[iPad] = digitMatrix->GetSignal(row,col-1+iPad,time);
582 }
583
584 // unfold:
585 ratio = Unfold(epsilon, padSignal);
586
587 // set signal on overlapping pad to ratio
588 clusterSignal[2] *= ratio;
589 }
590 }
591
592 switch (clusteringMethod) {
593 case 1:
594 // method 1: simply center of mass
595 clusterPads[3] = row + 0.5;
596 clusterPads[4] = col - 0.5 + (clusterSignal[2] - clusterSignal[0]) /
597 (clusterSignal[1] + clusterSignal[2] + clusterSignal[3]);
598 clusterPads[5] = time + 0.5;
599
600 nClusters++;
601 break;
602 case 2:
603 // method 2: integral gauss fit on 3 pads
604 TH1F *hPadCharges = new TH1F("hPadCharges", "Charges on center 3 pads"
605 , 5, -1.5, 3.5);
606 for (Int_t iCol = -1; iCol <= 3; iCol++) {
607 if (clusterSignal[iCol] < 1) clusterSignal[iCol] = 1;
608 hPadCharges->Fill(iCol, clusterSignal[iCol]);
609 }
610 hPadCharges->Fit("gaus", "IQ", "SAME", -0.5, 2.5);
611 TF1 *fPadChargeFit = hPadCharges->GetFunction("gaus");
612 Double_t colMean = fPadChargeFit->GetParameter(1);
613
614 clusterPads[3] = row + 0.5;
615 clusterPads[4] = col - 1.5 + colMean;
616 clusterPads[5] = time + 0.5;
617
618 delete hPadCharges;
619
620 nClusters++;
621 break;
622 }
623
624 Float_t clusterCharge = clusterSignal[0]
625 + clusterSignal[1]
626 + clusterSignal[2];
627 clusters[4] = (Int_t)clusterCharge;
628
629 Int_t trackSave[3];
630 for (Int_t iTrack = 0; iTrack < 3; iTrack++) {
631 trackSave[iTrack] = digitMatrix->GetTrack(row,col,time,iTrack);
632 }
633
634 // Calculate cluster position in ALICE refFrame coords
635 // and set array clusterPos to calculated values
636 Pads2XYZ(clusterPads, clusterPos);
637
638 // Add cluster to reconstruction tree
639 AddCluster(trackSave,clusters,clusterPos);
640
641 }
82bbf98a 642
5c7f4665 643 } // time
644 } // col
645 } // row
646
647 printf("AliTRDv1::Digits2Clusters -- Number of clusters found: %d\n",nClusters);
648
649 delete digitMatrix;
650 delete maximaMatrix;
651
652 } // isect
653 } // iplan
654 } // icham
655
656 // Fill the cluster-tree
657 printf("AliTRDv1::Digits2Clusters -- Total number of clusters found: %d\n"
658 ,fClusters->GetEntries());
659 printf("AliTRDv1::Digits2Clusters -- Fill the cluster tree\n");
660 ClusterTree->Fill();
661
662}
663
664//_____________________________________________________________________________
665void AliTRDv1::Init()
666{
667 //
668 // Initialise Transition Radiation Detector after geometry has been built.
669 // Includes the default settings of all parameter for the digitization.
670 //
671
672 AliTRD::Init();
673
674 printf(" Slow simulator\n");
675 if (fSensPlane)
676 printf(" Only plane %d is sensitive\n",fSensPlane);
677 if (fSensChamber)
678 printf(" Only chamber %d is sensitive\n",fSensChamber);
679 if (fSensSector)
680 printf(" Only sector %d is sensitive\n",fSensSector);
681
682 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
683 const Float_t kPoti = 12.1;
684 // Maximum energy (50 keV);
685 const Float_t kEend = 50000.0;
686 // Ermilova distribution for the delta-ray spectrum
687 Float_t Poti = TMath::Log(kPoti);
688 Float_t Eend = TMath::Log(kEend);
689 fDeltaE = new TF1("deltae",Ermilova,Poti,Eend,0);
690
691 // Identifier of the sensitive volume (drift region)
692 fIdSens = gMC->VolId("UL05");
82bbf98a 693
694 // Identifier of the TRD-driftchambers
695 fIdChamber1 = gMC->VolId("UCIO");
696 fIdChamber2 = gMC->VolId("UCIM");
697 fIdChamber3 = gMC->VolId("UCII");
698
5c7f4665 699 // The default parameter for the digitization
700 if (!(fGasGain)) fGasGain = 2.0E3;
701 if (!(fNoise)) fNoise = 3000.;
702 if (!(fChipGain)) fChipGain = 10.;
703 if (!(fADCoutRange)) fADCoutRange = 255.;
704 if (!(fADCinRange)) fADCinRange = 2000.;
705 if (!(fADCthreshold)) fADCthreshold = 1;
706
707 // Transverse and longitudinal diffusion coefficients (Xe/Isobutane)
708 if (!(fDiffusionT)) fDiffusionT = 0.060;
709 if (!(fDiffusionL)) fDiffusionL = 0.017;
710
711 // The default parameter for the clustering
712 if (!(fClusMaxThresh)) fClusMaxThresh = 5.0;
713 if (!(fClusSigThresh)) fClusSigThresh = 2.0;
714 if (!(fClusMethod)) fClusMethod = 1;
715
716 for (Int_t i = 0; i < 80; i++) printf("*");
717 printf("\n");
718
fe4da5cc 719}
720
721//_____________________________________________________________________________
5c7f4665 722Float_t AliTRDv1::PadResponse(Float_t x)
fe4da5cc 723{
724 //
5c7f4665 725 // The pad response for the chevron pads.
726 // We use a simple Gaussian approximation which should be good
727 // enough for our purpose.
fe4da5cc 728 //
d3f347ff 729
5c7f4665 730 // The parameters for the response function
731 const Float_t aa = 0.8872;
732 const Float_t bb = -0.00573;
733 const Float_t cc = 0.454;
734 const Float_t cc2 = cc*cc;
735
736 Float_t pr = aa * (bb + TMath::Exp(-x*x / (2. * cc2)));
737
738 return (pr);
739
740}
741
742//_____________________________________________________________________________
743void AliTRDv1::SetSensPlane(Int_t iplane)
744{
745 //
746 // Defines the hit-sensitive plane (1-6)
747 //
82bbf98a 748
5c7f4665 749 if ((iplane < 0) || (iplane > 6)) {
750 printf("Wrong input value: %d\n",iplane);
751 printf("Use standard setting\n");
752 fSensPlane = 0;
753 fSensSelect = 0;
754 return;
755 }
82bbf98a 756
5c7f4665 757 fSensSelect = 1;
758 fSensPlane = iplane;
82bbf98a 759
5c7f4665 760}
761
762//_____________________________________________________________________________
763void AliTRDv1::SetSensChamber(Int_t ichamber)
764{
765 //
766 // Defines the hit-sensitive chamber (1-5)
767 //
768
769 if ((ichamber < 0) || (ichamber > 5)) {
770 printf("Wrong input value: %d\n",ichamber);
771 printf("Use standard setting\n");
772 fSensChamber = 0;
773 fSensSelect = 0;
774 return;
775 }
776
777 fSensSelect = 1;
778 fSensChamber = ichamber;
779
780}
781
782//_____________________________________________________________________________
783void AliTRDv1::SetSensSector(Int_t isector)
784{
785 //
786 // Defines the hit-sensitive sector (1-18)
787 //
788
789 if ((isector < 0) || (isector > 18)) {
790 printf("Wrong input value: %d\n",isector);
791 printf("Use standard setting\n");
792 fSensSector = 0;
793 fSensSelect = 0;
794 return;
795 }
796
797 fSensSelect = 1;
798 fSensSector = isector;
799
800}
801
802//_____________________________________________________________________________
803void AliTRDv1::StepManager()
804{
805 //
806 // Called at every step in the Transition Radiation Detector version 2.
807 // Slow simulator. Every charged track produces electron cluster as hits
808 // along its path across the drift volume. The step size is set acording
809 // to Bethe-Bloch. The energy distribution of the delta electrons follows
810 // a spectrum taken from Ermilova et al.
811 //
812
813 Int_t iIdSens, icSens;
814 Int_t iIdSpace, icSpace;
815 Int_t iIdChamber, icChamber;
816 Int_t vol[3];
817 Int_t iPid;
818
819 Float_t hits[4];
820 Float_t random[1];
821 Float_t charge;
822 Float_t aMass;
823
824 Double_t pTot;
825 Double_t qTot;
826 Double_t eDelta;
827 Double_t betaGamma, pp;
828
829 TLorentzVector pos, mom;
82bbf98a 830 TClonesArray &lhits = *fHits;
831
5c7f4665 832 const Double_t kBig = 1.0E+12;
833
834 // Ionization energy
835 const Float_t kWion = 22.04;
836 // Maximum energy for e+ e- g for the step-size calculation
837 const Float_t kPTotMax = 0.002;
838 // Plateau value of the energy-loss for electron in xenon
839 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
840 //const Double_t kPlateau = 1.70;
841 // the averaged value (26/3/99)
842 const Float_t kPlateau = 1.55;
843 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
844 const Float_t kPrim = 48.0;
845 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
846 const Float_t kPoti = 12.1;
847
848 // Set the maximum step size to a very large number for all
849 // neutral particles and those outside the driftvolume
850 gMC->SetMaxStep(kBig);
851
852 // Use only charged tracks
853 if (( gMC->TrackCharge() ) &&
854 (!gMC->IsTrackStop() ) &&
855 (!gMC->IsTrackDisappeared())) {
fe4da5cc 856
5c7f4665 857 // Inside a sensitive volume?
82bbf98a 858 iIdSens = gMC->CurrentVolID(icSens);
859 if (iIdSens == fIdSens) {
860
82bbf98a 861 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
862 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
fe4da5cc 863
5c7f4665 864 // Calculate the energy of the delta-electrons
865 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
866 eDelta = TMath::Max(eDelta,0.0);
867
868 // The number of secondary electrons created
869 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
870
871 // The hit coordinates and charge
872 gMC->TrackPosition(pos);
873 hits[0] = pos[0];
874 hits[1] = pos[1];
875 hits[2] = pos[2];
876 hits[3] = qTot;
877
fe4da5cc 878 // The sector number
90f8d287 879 Float_t phi = pos[1] != 0 ? kRaddeg*TMath::ATan2(pos[0],pos[1]) : (pos[0] > 0 ? 180. : 0.);
5c7f4665 880 vol[0] = ((Int_t) (phi / 20)) + 1;
82bbf98a 881
d3f347ff 882 // The chamber number
883 // 1: outer left
82bbf98a 884 // 2: middle left
d3f347ff 885 // 3: inner
82bbf98a 886 // 4: middle right
d3f347ff 887 // 5: outer right
82bbf98a 888 if (iIdChamber == fIdChamber1)
889 vol[1] = (hits[2] < 0 ? 1 : 5);
890 else if (iIdChamber == fIdChamber2)
891 vol[1] = (hits[2] < 0 ? 2 : 4);
892 else if (iIdChamber == fIdChamber3)
d3f347ff 893 vol[1] = 3;
82bbf98a 894
fe4da5cc 895 // The plane number
82bbf98a 896 vol[2] = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6;
897
5c7f4665 898 // Check on selected volumes
899 Int_t addthishit = 1;
900 if (fSensSelect) {
901 if ((fSensPlane) && (vol[2] != fSensPlane )) addthishit = 0;
902 if ((fSensChamber) && (vol[1] != fSensChamber)) addthishit = 0;
903 if ((fSensSector) && (vol[0] != fSensSector )) addthishit = 0;
904 }
905
906 // Add this hit
907 if (addthishit) {
908
909 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack(),vol,hits);
910
911 // The energy loss according to Bethe Bloch
912 gMC->TrackMomentum(mom);
913 pTot = mom.Rho();
914 iPid = gMC->TrackPid();
915 if ( (iPid > 3) ||
916 ((iPid <= 3) && (pTot < kPTotMax))) {
917 aMass = gMC->TrackMass();
918 betaGamma = pTot / aMass;
919 pp = kPrim * BetheBloch(betaGamma);
920 // Take charge > 1 into account
921 charge = gMC->TrackCharge();
922 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
923 }
924 // Electrons above 20 Mev/c are at the plateau
925 else {
926 pp = kPrim * kPlateau;
927 }
928
929 // Calculate the maximum step size for the next tracking step
930 if (pp > 0) {
931 do
932 gMC->Rndm(random,1);
933 while ((random[0] == 1.) || (random[0] == 0.));
934 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
935 }
936
937 }
938 else {
939 // set step size to maximal value
940 gMC->SetMaxStep(kBig);
941 }
d3f347ff 942
943 }
944
5c7f4665 945 }
946
947}
948
949//_____________________________________________________________________________
950Double_t AliTRDv1::BetheBloch(Double_t bg)
951{
952 //
953 // Parametrization of the Bethe-Bloch-curve
954 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
955 //
956
957 // This parameters have been adjusted to averaged values from GEANT
958 const Double_t kP1 = 7.17960e-02;
959 const Double_t kP2 = 8.54196;
960 const Double_t kP3 = 1.38065e-06;
961 const Double_t kP4 = 5.30972;
962 const Double_t kP5 = 2.83798;
963
964 // This parameters have been adjusted to Xe-data found in:
965 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
966 //const Double_t kP1 = 0.76176E-1;
967 //const Double_t kP2 = 10.632;
968 //const Double_t kP3 = 3.17983E-6;
969 //const Double_t kP4 = 1.8631;
970 //const Double_t kP5 = 1.9479;
971
972 if (bg > 0) {
973 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
974 Double_t aa = TMath::Power(yy,kP4);
975 Double_t bb = TMath::Power((1./bg),kP5);
976 bb = TMath::Log(kP3 + bb);
977 return ((kP2 - aa - bb)*kP1 / aa);
978 }
979 else
980 return 0;
d3f347ff 981
fe4da5cc 982}
5c7f4665 983
984//_____________________________________________________________________________
985Double_t Ermilova(Double_t *x, Double_t *)
986{
987 //
988 // Calculates the delta-ray energy distribution according to Ermilova.
989 // Logarithmic scale !
990 //
991
992 Double_t energy;
993 Double_t dpos;
994 Double_t dnde;
995
996 Int_t pos1, pos2;
997
998 const Int_t nV = 31;
999
1000 Float_t vxe[nV] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
1001 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
1002 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
1003 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
1004 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
1005 , 9.4727, 9.9035,10.3735,10.5966,10.8198
1006 ,11.5129 };
1007
1008 Float_t vye[nV] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
1009 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
1010 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
1011 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
1012 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
1013 , 0.04 , 0.023, 0.015, 0.011, 0.01
1014 , 0.004 };
1015
1016 energy = x[0];
1017
1018 // Find the position
1019 pos1 = pos2 = 0;
1020 dpos = 0;
1021 do {
1022 dpos = energy - vxe[pos2++];
1023 }
1024 while (dpos > 0);
1025 pos2--;
1026 if (pos2 > nV) pos2 = nV;
1027 pos1 = pos2 - 1;
1028
1029 // Differentiate between the sampling points
1030 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
1031
1032 return dnde;
1033
1034}
1035
1036//_____________________________________________________________________________
1037void AliTRDv1::Pads2XYZ(Float_t *pads, Float_t *pos)
1038{
1039 // Method to convert pad coordinates (row,col,time)
1040 // into ALICE reference frame coordinates (x,y,z)
1041
1042 Int_t chamber = (Int_t) pads[0]; // chamber info (1-5)
1043 Int_t sector = (Int_t) pads[1]; // sector info (1-18)
1044 Int_t plane = (Int_t) pads[2]; // plane info (1-6)
1045
1046 Int_t icham = chamber - 1; // chamber info (0-4)
1047 Int_t isect = sector - 1; // sector info (0-17)
1048 Int_t iplan = plane - 1; // plane info (0-5)
1049
1050 Float_t padRow = pads[3]; // Pad Row position
1051 Float_t padCol = pads[4]; // Pad Column position
1052 Float_t timeSlice = pads[5]; // Time "position"
1053
1054 // calculate (x,y) position in rotated chamber
1055 Float_t yRot = fCol0[iplan] + padCol * fColPadSize;
1056 Float_t xRot = fTime0[iplan] + timeSlice * fTimeBinSize;
1057 // calculate z-position:
1058 Float_t z = fRow0[iplan][icham][isect] + padRow * fRowPadSize;
1059
1060 /**
1061 rotate chamber back to original position
1062 1. mirror at y-axis, 2. rotate back to position (-phi)
1063 / cos(phi) -sin(phi) \ / -1 0 \ / -cos(phi) -sin(phi) \
1064 \ sin(phi) cos(phi) / * \ 0 1 / = \ -sin(phi) cos(phi) /
1065 **/
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 Float_t phi = 2*kPI / kNsect * ((Float_t) sector - 0.5);
1070 Float_t x = -xRot * TMath::Cos(phi) + yRot * TMath::Sin(phi);
1071 Float_t y = xRot * TMath::Sin(phi) + yRot * TMath::Cos(phi);
1072
1073 // Setting values
1074 pos[0] = x;
1075 pos[1] = y;
1076 pos[2] = z;
1077
1078}
1079
1080//_____________________________________________________________________________
1081Float_t AliTRDv1::Unfold(Float_t eps, Float_t* padSignal)
1082{
1083 // Method to unfold neighbouring maxima.
1084 // The charge ratio on the overlapping pad is calculated
1085 // until there is no more change within the range given by eps.
1086 // The resulting ratio is then returned to the calling method.
1087
1088 Int_t itStep = 0; // count iteration steps
1089
1090 Float_t ratio = 0.5; // start value for ratio
1091 Float_t prevRatio = 0; // store previous ratio
1092
1093 Float_t newLeftSignal[3] = {0}; // array to store left cluster signal
1094 Float_t newRightSignal[3] = {0}; // array to store right cluster signal
1095
1096 // start iteration:
1097 while ((TMath::Abs(prevRatio - ratio) > eps) && (itStep < 10)) {
1098
1099 itStep++;
1100 prevRatio = ratio;
1101
1102 // cluster position according to charge ratio
1103 Float_t maxLeft = (ratio*padSignal[2] - padSignal[0]) /
1104 (padSignal[0] + padSignal[1] + ratio*padSignal[2]);
1105 Float_t maxRight = (padSignal[4] - (1-ratio)*padSignal[2]) /
1106 ((1-ratio)*padSignal[2] + padSignal[3] + padSignal[4]);
1107
1108 // set cluster charge ratio
1109 Float_t ampLeft = padSignal[1];
1110 Float_t ampRight = padSignal[3];
1111
1112 // apply pad response to parameters
1113 newLeftSignal[0] = ampLeft*PadResponse(-1 - maxLeft);
1114 newLeftSignal[1] = ampLeft*PadResponse( 0 - maxLeft);
1115 newLeftSignal[2] = ampLeft*PadResponse( 1 - maxLeft);
1116
1117 newRightSignal[0] = ampRight*PadResponse(-1 - maxRight);
1118 newRightSignal[1] = ampRight*PadResponse( 0 - maxRight);
1119 newRightSignal[2] = ampRight*PadResponse( 1 - maxRight);
1120
1121 // calculate new overlapping ratio
1122 ratio = newLeftSignal[2]/(newLeftSignal[2] + newRightSignal[0]);
1123
1124 }
1125
1126 return ratio;
1127
1128}
1129