Added protections against using the wrong version of FRAME
[u/mrichter/AliRoot.git] / TRD / AliTRDv2.cxx
CommitLineData
4c039060 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
7 * Permission to use, copy, modify and distribute this software and its *
8 * documentation strictly for non-commercial purposes is hereby granted *
9 * without fee, provided that the above copyright notice appears in all *
10 * copies and that both the copyright notice and this permission notice *
11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
15
16/*
17$Log$
ab76897d 18Revision 1.14 1999/10/04 14:48:07 fca
19Avoid warnings on non-ansi compiler HP-UX CC
20
7d83513f 21Revision 1.13 1999/09/29 09:24:35 fca
22Introduction of the Copyright and cvs Log
23
4c039060 24*/
25
fe4da5cc 26///////////////////////////////////////////////////////////////////////////////
27// //
28// Transition Radiation Detector version 2 -- detailed simulation //
29// //
30//Begin_Html
31/*
1439f98e 32<img src="picts/AliTRDv2Class.gif">
fe4da5cc 33*/
34//End_Html
35// //
36// //
37///////////////////////////////////////////////////////////////////////////////
38
ab76897d 39#include <stdlib.h>
40
fe4da5cc 41#include <TMath.h>
fe4da5cc 42#include <TVector.h>
99d5402e 43#include <TRandom.h>
fe4da5cc 44
fe4da5cc 45#include "AliTRDv2.h"
99d5402e 46#include "AliTRDmatrix.h"
fe4da5cc 47#include "AliRun.h"
fe4da5cc 48#include "AliMC.h"
d3f347ff 49#include "AliConst.h"
fe4da5cc 50
51ClassImp(AliTRDv2)
52
53//_____________________________________________________________________________
54AliTRDv2::AliTRDv2(const char *name, const char *title)
55 :AliTRD(name, title)
56{
57 //
58 // Standard constructor for Transition Radiation Detector version 2
59 //
82bbf98a 60
99d5402e 61 fIdSens = 0;
82bbf98a 62
99d5402e 63 fIdSpace1 = 0;
64 fIdSpace2 = 0;
65 fIdSpace3 = 0;
82bbf98a 66
99d5402e 67 fIdChamber1 = 0;
68 fIdChamber2 = 0;
69 fIdChamber3 = 0;
82bbf98a 70
99d5402e 71 fSensSelect = 0;
72 fSensPlane = 0;
73 fSensChamber = 0;
74 fSensSector = 0;
82bbf98a 75
7d83513f 76 Int_t iplan;
77
78 for (iplan = 0; iplan < kNplan; iplan++) {
99d5402e 79 for (Int_t icham = 0; icham < kNcham; icham++) {
80 fRowMax[iplan][icham] = 0;
81 }
82 fColMax[iplan] = 0;
83 }
84 fTimeMax = 0;
85
86 fRowPadSize = 0;
87 fColPadSize = 0;
88 fTimeBinSize = 0;
89
90 fGasGain = 0;
91 fNoise = 0;
92 fChipGain = 0;
93 fADCoutRange = 0;
94 fADCinRange = 0;
95 fADCthreshold = 0;
96
97 fDiffusionT = 0;
98 fDiffusionL = 0;
99
100 fDeltaE = NULL;
d3f347ff 101
fe4da5cc 102 SetBufferSize(128000);
82bbf98a 103
fe4da5cc 104}
d3f347ff 105
99d5402e 106//_____________________________________________________________________________
d3f347ff 107AliTRDv2::~AliTRDv2()
108{
82bbf98a 109
99d5402e 110 if (fDeltaE) delete fDeltaE;
82bbf98a 111
d3f347ff 112}
fe4da5cc 113
114//_____________________________________________________________________________
115void AliTRDv2::CreateGeometry()
116{
117 //
82bbf98a 118 // Create the GEANT geometry for the Transition Radiation Detector - Version 2
fe4da5cc 119 // This version covers the full azimuth.
d3f347ff 120 //
82bbf98a 121 // Author: Christoph Blume (C.Blume@gsi.de) 20/07/99
fe4da5cc 122 //
d3f347ff 123
82bbf98a 124 Float_t xpos, ypos, zpos;
d3f347ff 125
82bbf98a 126 // Check that FRAME is there otherwise we have no place where to put the TRD
127 AliModule* FRAME = gAlice->GetModule("FRAME");
128 if (!FRAME) return;
d3f347ff 129
82bbf98a 130 // Define the chambers
131 AliTRD::CreateGeometry();
fe4da5cc 132
82bbf98a 133 // Position the the TRD-sectors in all TRD-volumes in the spaceframe
134 xpos = 0.;
135 ypos = 0.;
136 zpos = 0.;
137 gMC->Gspos("TRD ",1,"BTR1",xpos,ypos,zpos,0,"ONLY");
138 gMC->Gspos("TRD ",2,"BTR2",xpos,ypos,zpos,0,"ONLY");
139 gMC->Gspos("TRD ",3,"BTR3",xpos,ypos,zpos,0,"ONLY");
fe4da5cc 140
fe4da5cc 141}
142
143//_____________________________________________________________________________
144void AliTRDv2::CreateMaterials()
145{
146 //
147 // Create materials for the Transition Radiation Detector version 2
148 //
82bbf98a 149
fe4da5cc 150 AliTRD::CreateMaterials();
82bbf98a 151
fe4da5cc 152}
153
154//_____________________________________________________________________________
99d5402e 155void AliTRDv2::Diffusion(Float_t driftlength, Float_t *xyz)
fe4da5cc 156{
157 //
99d5402e 158 // Applies the diffusion smearing to the position of a single electron
fe4da5cc 159 //
d3f347ff 160
99d5402e 161 if ((driftlength > 0) &&
162 (driftlength < kDrThick)) {
163 Float_t driftSqrt = TMath::Sqrt(driftlength);
164 Float_t sigmaT = driftSqrt * fDiffusionT;
165 Float_t sigmaL = driftSqrt * fDiffusionL;
166 xyz[0] = gRandom->Gaus(xyz[0], sigmaL);
167 xyz[1] = gRandom->Gaus(xyz[1], sigmaT);
168 xyz[2] = gRandom->Gaus(xyz[2], sigmaT);
169 }
170 else {
171 xyz[0] = 0.0;
172 xyz[1] = 0.0;
173 xyz[2] = 0.0;
174 }
175
176}
177
178//_____________________________________________________________________________
179void AliTRDv2::Hits2Digits()
180{
181 //
182 // Creates TRD digits from hits. This procedure includes the following:
183 // - Diffusion
184 // - Gas gain including fluctuations
185 // - Pad-response (simple Gaussian approximation)
186 // - Electronics noise
187 // - Electronics gain
188 // - Digitization
189 // - ADC threshold
190 // The corresponding parameter can be adjusted via the various Set-functions.
191 // If these parameters are not explicitly set, default values are used (see
192 // Init-function).
193 // To produce digits from a galice.root file with TRD-hits use the
194 // digitsCreate.C macro.
195 //
196
197 printf(" Start creating digits\n");
198
199 ///////////////////////////////////////////////////////////////
200 // Parameter
201 ///////////////////////////////////////////////////////////////
202
203 // Converts number of electrons to fC
204 const Float_t el2fC = 1.602E-19 * 1.0E15;
205
206 ///////////////////////////////////////////////////////////////
207
208 Int_t nBytes = 0;
209
210 AliTRDhit *TRDhit;
211
7d83513f 212 Int_t iplan;
213 Int_t iRow;
214
99d5402e 215 // Position of pad 0,0,0
216 //
217 // chambers seen from the top:
218 // +----------------------------+
219 // | |
220 // | | ^
221 // | | rphi|
222 // | | |
223 // |0 | |
224 // +----------------------------+ +------>
225 // z
226 // chambers seen from the side: ^
227 // +----------------------------+ time|
228 // | | |
229 // |0 | |
230 // +----------------------------+ +------>
231 // z
232 //
233 // The pad row (z-direction)
234 Float_t row0[kNplan][kNcham];
7d83513f 235 for (iplan = 0; iplan < kNplan; iplan++) {
99d5402e 236 row0[iplan][0] = -fClengthI[iplan]/2. - fClengthM[iplan] - fClengthO[iplan]
237 + kCcthick;
238 row0[iplan][1] = -fClengthI[iplan]/2. - fClengthM[iplan]
239 + kCcthick;
240 row0[iplan][2] = -fClengthI[iplan]/2.
241 + kCcthick;
242 row0[iplan][3] = fClengthI[iplan]/2.
243 + kCcthick;
244 row0[iplan][4] = fClengthI[iplan]/2. + fClengthM[iplan]
245 + kCcthick;
246 }
247 // The pad column (rphi-direction)
248 Float_t col0[kNplan];
7d83513f 249 for (iplan = 0; iplan < kNplan; iplan++) {
99d5402e 250 col0[iplan] = -fCwidth[iplan]/2. + kCcthick;
251 }
252 // The time bucket
253 Float_t time0[kNplan];
7d83513f 254 for (iplan = 0; iplan < kNplan; iplan++) {
99d5402e 255 time0[iplan] = kRmin + kCcframe/2. + kDrZpos - 0.5 * kDrThick
256 + iplan * (kCheight + kCspace);
257 }
258
259 // Get the pointer to the hit tree
260 TTree *HitTree = gAlice->TreeH();
261 // Get the pointer to the digits tree
262 TTree *DigitsTree = gAlice->TreeD();
263
264 // Get the number of entries in the hit tree
265 // (Number of primary particles creating a hit somewhere)
266 Int_t nTrack = (Int_t) HitTree->GetEntries();
267
268 Int_t chamBeg = 0;
269 Int_t chamEnd = kNcham;
270 if (fSensChamber) chamEnd = chamBeg = fSensChamber;
271 Int_t planBeg = 0;
272 Int_t planEnd = kNplan;
273 if (fSensPlane) planEnd = planBeg = fSensPlane;
274 Int_t sectBeg = 0;
275 Int_t sectEnd = kNsect;
276 if (fSensSector) sectEnd = sectBeg = fSensSector;
277
278 // Loop through all the chambers
279 for (Int_t icham = chamBeg; icham < chamEnd; icham++) {
7d83513f 280 for (iplan = planBeg; iplan < planEnd; iplan++) {
99d5402e 281 for (Int_t isect = sectBeg; isect < sectEnd; isect++) {
282
283 printf(" Digitizing chamber %d, plane %d, sector %d\n"
284 ,icham+1,iplan+1,isect+1);
285
286 // Create a detector matrix to keep the signal and track numbers
287 AliTRDmatrix *matrix = new AliTRDmatrix(fRowMax[iplan][icham]
288 ,fColMax[iplan]
289 ,fTimeMax
290 ,isect+1,icham+1,iplan+1);
291
292 // Loop through all entries in the tree
293 for (Int_t iTrack = 0; iTrack < nTrack; iTrack++) {
294
295 gAlice->ResetHits();
296 nBytes += HitTree->GetEvent(iTrack);
297
298 // Get the number of hits in the TRD created by this particle
299 Int_t nHit = fHits->GetEntriesFast();
300
301 // Loop through the TRD hits
302 for (Int_t iHit = 0; iHit < nHit; iHit++) {
303
304 if (!(TRDhit = (AliTRDhit *) fHits->UncheckedAt(iHit)))
305 continue;
306
307 Float_t x = TRDhit->fX;
308 Float_t y = TRDhit->fY;
309 Float_t z = TRDhit->fZ;
310 Float_t q = TRDhit->fQ;
311 Int_t track = TRDhit->fTrack;
312 Int_t plane = TRDhit->fPlane;
313 Int_t sector = TRDhit->fSector;
314 Int_t chamber = TRDhit->fChamber;
315
316 if ((sector != isect+1) ||
317 (plane != iplan+1) ||
318 (chamber != icham+1))
319 continue;
320
321 // Rotate the sectors on top of each other
322 Float_t phi = 2.0 * kPI / (Float_t) kNsect
323 * ((Float_t) sector - 0.5);
324 Float_t xRot = -x * TMath::Cos(phi) + y * TMath::Sin(phi);
325 Float_t yRot = x * TMath::Sin(phi) + y * TMath::Cos(phi);
326 Float_t zRot = z;
327
328 // The hit position in pad coordinates (center pad)
329 // The pad row (z-direction)
330 Int_t rowH = (Int_t) ((zRot - row0[iplan][icham]) / fRowPadSize);
331 // The pad column (rphi-direction)
332 Int_t colH = (Int_t) ((yRot - col0[iplan] ) / fColPadSize);
333 // The time bucket
334 Int_t timeH = (Int_t) ((xRot - time0[iplan] ) / fTimeBinSize);
335
336 // Array to sum up the signal in a box surrounding the
337 // hit postition
338 const Int_t timeBox = 5;
339 const Int_t colBox = 7;
340 const Int_t rowBox = 5;
341 Float_t signalSum[rowBox][colBox][timeBox];
7d83513f 342 for (iRow = 0; iRow < rowBox; iRow++ ) {
99d5402e 343 for (Int_t iCol = 0; iCol < colBox; iCol++ ) {
344 for (Int_t iTime = 0; iTime < timeBox; iTime++) {
345 signalSum[iRow][iCol][iTime] = 0;
346 }
347 }
348 }
349
350 // Loop over all electrons of this hit
351 Int_t nEl = (Int_t) q;
352 for (Int_t iEl = 0; iEl < nEl; iEl++) {
353
354 // Apply the diffusion smearing
355 Float_t driftlength = xRot - time0[iplan];
356 Float_t xyz[3];
357 xyz[0] = xRot;
358 xyz[1] = yRot;
359 xyz[2] = zRot;
360 Diffusion(driftlength,xyz);
361
362 // At this point absorption effects that depend on the
363 // driftlength could be taken into account.
364
365 // The electron position and the distance to the hit position
366 // in pad units
367 // The pad row (z-direction)
368 Int_t rowE = (Int_t) ((xyz[2] - row0[iplan][icham]) / fRowPadSize);
369 Int_t rowD = rowH - rowE;
370 // The pad column (rphi-direction)
371 Int_t colE = (Int_t) ((xyz[1] - col0[iplan] ) / fColPadSize);
372 Int_t colD = colH - colE;
373 // The time bucket
374 Int_t timeE = (Int_t) ((xyz[0] - time0[iplan] ) / fTimeBinSize);
375 Int_t timeD = timeH - timeE;
376
377 // Apply the gas gain including fluctuations
378 Int_t signal = (Int_t) (-fGasGain * TMath::Log(gRandom->Rndm()));
379
380 // The distance of the electron to the center of the pad
381 // in units of pad width
382 Float_t dist = (xyz[1] - col0[iplan] - (colE + 0.5) * fColPadSize)
383 / fColPadSize;
384
385 // Sum up the signal in the different pixels
386 // and apply the pad response
387 Int_t rowIdx = rowD + (Int_t) ( rowBox / 2);
388 Int_t colIdx = colD + (Int_t) ( colBox / 2);
389 Int_t timeIdx = timeD + (Int_t) (timeBox / 2);
390 signalSum[rowIdx][colIdx-1][timeIdx] += PadResponse(dist-1.) * signal;
391 signalSum[rowIdx][colIdx ][timeIdx] += PadResponse(dist ) * signal;
392 signalSum[rowIdx][colIdx+1][timeIdx] += PadResponse(dist+1.) * signal;
393
394 }
395
396 // Add the padcluster to the detector matrix
7d83513f 397 for (iRow = 0; iRow < rowBox; iRow++ ) {
99d5402e 398 for (Int_t iCol = 0; iCol < colBox; iCol++ ) {
399 for (Int_t iTime = 0; iTime < timeBox; iTime++) {
400
401 Int_t rowB = rowH + iRow - (Int_t) ( rowBox / 2);
402 Int_t colB = colH + iCol - (Int_t) ( colBox / 2);
403 Int_t timeB = timeH + iTime - (Int_t) (timeBox / 2);
404
405 Float_t signalB = signalSum[iRow][iCol][iTime];
406 if (signalB > 0.0) {
407 matrix->AddSignal(rowB,colB,timeB,signalB);
408 if (!(matrix->AddTrack(rowB,colB,timeB,track)))
409 printf("More than three tracks in a pixel!\n");
410 }
411
412 }
413 }
414 }
415
416 }
417
418 }
419
420 // Create the hits for this chamber
421 for (Int_t iRow = 0; iRow < fRowMax[iplan][icham]; iRow++ ) {
422 for (Int_t iCol = 0; iCol < fColMax[iplan] ; iCol++ ) {
423 for (Int_t iTime = 0; iTime < fTimeMax ; iTime++) {
424
425 Float_t signalAmp = matrix->GetSignal(iRow,iCol,iTime);
426
427 // Add the noise
7d83513f 428 signalAmp = TMath::Max(gRandom->Gaus(signalAmp,fNoise),(Float_t) 0.0);
99d5402e 429 // Convert to fC
430 signalAmp *= el2fC;
431 // Convert to mV
432 signalAmp *= fChipGain;
433 // Convert to ADC counts
434 Int_t adc = (Int_t) (signalAmp * (fADCoutRange / fADCinRange));
435
436 // Apply threshold on ADC value
437 if (adc > fADCthreshold) {
438
439 Int_t trackSave[3];
440 for (Int_t ii = 0; ii < 3; ii++) {
441 trackSave[ii] = matrix->GetTrack(iRow,iCol,iTime,ii);
442 }
443
444 Int_t digits[7];
445 digits[0] = matrix->GetSector();
446 digits[1] = matrix->GetChamber();
447 digits[2] = matrix->GetPlane();
448 digits[3] = iRow;
449 digits[4] = iCol;
450 digits[5] = iTime;
451 digits[6] = adc;
452
453 // Add this digit to the TClonesArray
454 AddDigit(trackSave,digits);
455
456 }
457
458 }
459 }
460 }
461
462 // Clean up
463 delete matrix;
464
465 }
466 }
467 }
468
469 // Fill the digits-tree
470 DigitsTree->Fill();
471
472}
473
474//_____________________________________________________________________________
475void AliTRDv2::Init()
476{
477 //
478 // Initialise Transition Radiation Detector after geometry has been built.
479 // Includes the default settings of all parameter for the digitization.
480 //
d3f347ff 481
ab76897d 482 printf("**************************************"
483 " TRD "
484 "**************************************\n");
485 printf("\n Version 2 of TRD initialing, "
486 "symmetric TRD\n\n");
487
fe4da5cc 488 AliTRD::Init();
d3f347ff 489
ab76897d 490
491 //
492 // Check that FRAME is there otherwise we have no place where to
493 // put TRD
494 AliModule* FRAME=gAlice->GetModule("FRAME");
495 if(!FRAME) {
496 Error("Ctor","TRD needs FRAME to be present\n");
497 exit(1);
498 } else
499 if(FRAME->IsVersion()!=1) {
500 Error("Ctor","FRAME version 1 needed with this version of TRD\n");
501 exit(1);
502 }
503
82bbf98a 504 if (fSensPlane)
505 printf(" Only plane %d is sensitive\n",fSensPlane);
506 if (fSensChamber)
507 printf(" Only chamber %d is sensitive\n",fSensChamber);
508 if (fSensSector)
509 printf(" Only sector %d is sensitive\n",fSensSector);
d3f347ff 510
99d5402e 511 for (Int_t i = 0; i < 80; i++) printf("*");
82bbf98a 512 printf("\n");
d3f347ff 513
99d5402e 514 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
515 const Float_t kPoti = 12.1;
516 // Maximum energy (50 keV);
517 const Float_t kEend = 50000.0;
d3f347ff 518 // Ermilova distribution for the delta-ray spectrum
82bbf98a 519 Float_t Poti = TMath::Log(kPoti);
520 Float_t Eend = TMath::Log(kEend);
d3f347ff 521 fDeltaE = new TF1("deltae",Ermilova,Poti,Eend,0);
522
82bbf98a 523 // Identifier of the sensitive volume (drift region)
524 fIdSens = gMC->VolId("UL05");
525
526 // Identifier of the TRD-spaceframe volumina
527 fIdSpace1 = gMC->VolId("B028");
528 fIdSpace2 = gMC->VolId("B029");
529 fIdSpace3 = gMC->VolId("B030");
530
531 // Identifier of the TRD-driftchambers
532 fIdChamber1 = gMC->VolId("UCIO");
533 fIdChamber2 = gMC->VolId("UCIM");
534 fIdChamber3 = gMC->VolId("UCII");
535
99d5402e 536 // The default pad dimensions
537 if (!(fRowPadSize)) fRowPadSize = 4.5;
538 if (!(fColPadSize)) fColPadSize = 1.0;
539 if (!(fTimeBinSize)) fTimeBinSize = 0.1;
540
541 // The maximum number of pads
542 for (Int_t iplan = 0; iplan < kNplan; iplan++) {
543 // Rows
544 fRowMax[iplan][0] = 1 + TMath::Nint((fClengthO[iplan] - 2. * kCcthick)
545 / fRowPadSize - 0.5);
546 fRowMax[iplan][1] = 1 + TMath::Nint((fClengthM[iplan] - 2. * kCcthick)
547 / fRowPadSize - 0.5);
548 fRowMax[iplan][2] = 1 + TMath::Nint((fClengthI[iplan] - 2. * kCcthick)
549 / fRowPadSize - 0.5);
550 fRowMax[iplan][3] = 1 + TMath::Nint((fClengthM[iplan] - 2. * kCcthick)
551 / fRowPadSize - 0.5);
552 fRowMax[iplan][4] = 1 + TMath::Nint((fClengthO[iplan] - 2. * kCcthick)
553 / fRowPadSize - 0.5);
554 // Columns
555 fColMax[iplan] = 1 + TMath::Nint((fCwidth[iplan] - 2. * kCcthick)
556 / fColPadSize - 0.5);
557 }
558 // Time buckets
559 fTimeMax = 1 + TMath::Nint(kDrThick / fTimeBinSize - 0.5);
560
561 // The default parameter for the digitization
562 if (!(fGasGain)) fGasGain = 2.0E3;
563 if (!(fNoise)) fNoise = 3000.;
564 if (!(fChipGain)) fChipGain = 10.;
565 if (!(fADCoutRange)) fADCoutRange = 255.;
566 if (!(fADCinRange)) fADCinRange = 2000.;
567 if (!(fADCthreshold)) fADCthreshold = 0;
568
569 // Transverse and longitudinal diffusion coefficients (Xe/Isobutane)
570 if (!(fDiffusionT)) fDiffusionT = 0.060;
571 if (!(fDiffusionL)) fDiffusionL = 0.017;
572
ab76897d 573 printf("**************************************"
574 " TRD "
575 "**************************************\n");
99d5402e 576}
577
578//_____________________________________________________________________________
579void AliTRDv2::MakeBranch(Option_t* option)
580{
581 //
582 // Create Tree branches for the TRD digits.
583 //
584
585 Int_t buffersize = 4000;
586 Char_t branchname[10];
587
588 sprintf(branchname,"%s",GetName());
589
590 AliDetector::MakeBranch(option);
591
592 Char_t *D = strstr(option,"D");
593 if (fDigits && gAlice->TreeD() && D) {
594 gAlice->TreeD()->Branch(branchname,&fDigits, buffersize);
595 printf("Making Branch %s for digits\n",branchname);
596 }
597
598}
599
600//_____________________________________________________________________________
601Float_t AliTRDv2::PadResponse(Float_t x)
602{
603 //
604 // The pad response for the chevron pads.
605 // We use a simple Gaussian approximation which should be good
606 // enough for our purpose.
607 //
608
609 // The parameters for the response function
610 const Float_t aa = 0.8872;
611 const Float_t bb = -0.00573;
612 const Float_t cc = 0.454;
613 const Float_t cc2 = cc*cc;
614
615 Float_t pr = aa * (bb + TMath::Exp(-x*x / (2. * cc2)));
616
617 //TF1 *funPR = new TF1("funPR","[0]*([1]+exp(-x*x /(2.*[2])))",-3,3);
618 //funPR->SetParameter(0,aa );
619 //funPR->SetParameter(1,bb );
620 //funPR->SetParameter(2,cc2);
621 //
622 //Float_t pr = funPR->Eval(distance);
623 //
624 //delete funPR;
625
626 return (pr);
627
fe4da5cc 628}
629
630//_____________________________________________________________________________
82bbf98a 631void AliTRDv2::SetSensPlane(Int_t iplane)
fe4da5cc 632{
633 //
82bbf98a 634 // Defines the hit-sensitive plane (1-6)
fe4da5cc 635 //
d3f347ff 636
82bbf98a 637 if ((iplane < 0) || (iplane > 6)) {
638 printf("Wrong input value: %d\n",iplane);
639 printf("Use standard setting\n");
640 fSensPlane = 0;
641 fSensSelect = 0;
642 return;
643 }
d3f347ff 644
82bbf98a 645 fSensSelect = 1;
646 fSensPlane = iplane;
d3f347ff 647
82bbf98a 648}
d3f347ff 649
82bbf98a 650//_____________________________________________________________________________
651void AliTRDv2::SetSensChamber(Int_t ichamber)
652{
653 //
654 // Defines the hit-sensitive chamber (1-5)
655 //
656
657 if ((ichamber < 0) || (ichamber > 5)) {
658 printf("Wrong input value: %d\n",ichamber);
659 printf("Use standard setting\n");
660 fSensChamber = 0;
661 fSensSelect = 0;
662 return;
663 }
664
665 fSensSelect = 1;
666 fSensChamber = ichamber;
667
668}
669
670//_____________________________________________________________________________
671void AliTRDv2::SetSensSector(Int_t isector)
672{
673 //
674 // Defines the hit-sensitive sector (1-18)
675 //
676
677 if ((isector < 0) || (isector > 18)) {
678 printf("Wrong input value: %d\n",isector);
679 printf("Use standard setting\n");
680 fSensSector = 0;
681 fSensSelect = 0;
682 return;
683 }
684
685 fSensSelect = 1;
686 fSensSector = isector;
687
688}
689
690//_____________________________________________________________________________
691void AliTRDv2::StepManager()
692{
693 //
694 // Called at every step in the Transition Radiation Detector version 2.
695 // Slow simulator. Every charged track produces electron cluster as hits
696 // along its path across the drift volume. The step size is set acording
697 // to Bethe-Bloch. The energy distribution of the delta electrons follows
698 // a spectrum taken from Ermilova et al.
699 //
700
701 Int_t iIdSens, icSens;
702 Int_t iIdSpace, icSpace;
703 Int_t iIdChamber, icChamber;
704 Int_t vol[3];
705 Int_t iPid;
706
707 Int_t secMap1[10] = { 3, 7, 8, 9, 10, 11, 2, 1, 18, 17 };
708 Int_t secMap2[ 5] = { 16, 15, 14, 13, 12 };
709 Int_t secMap3[ 3] = { 5, 6, 4 };
710
711 Float_t hits[4];
712 Float_t random[1];
713 Float_t charge;
714 Float_t aMass;
0a6d8768 715
82bbf98a 716 Double_t pTot;
717 Double_t qTot;
718 Double_t eDelta;
719 Double_t betaGamma, pp;
d3f347ff 720
82bbf98a 721 TLorentzVector pos, mom;
fe4da5cc 722 TClonesArray &lhits = *fHits;
d3f347ff 723
82bbf98a 724 const Double_t kBig = 1.0E+12;
725
fe4da5cc 726 // Ionization energy
d3f347ff 727 const Float_t kWion = 22.04;
fe4da5cc 728 // Maximum energy for e+ e- g for the step-size calculation
d3f347ff 729 const Float_t kPTotMax = 0.002;
fe4da5cc 730 // Plateau value of the energy-loss for electron in xenon
731 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
d3f347ff 732 //const Double_t kPlateau = 1.70;
733 // the averaged value (26/3/99)
734 const Float_t kPlateau = 1.55;
fe4da5cc 735 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
d3f347ff 736 const Float_t kPrim = 48.0;
737 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
738 const Float_t kPoti = 12.1;
739
fe4da5cc 740 // Set the maximum step size to a very large number for all
741 // neutral particles and those outside the driftvolume
cfce8870 742 gMC->SetMaxStep(kBig);
d3f347ff 743
fe4da5cc 744 // Use only charged tracks
82bbf98a 745 if (( gMC->TrackCharge() ) &&
746 (!gMC->IsTrackStop() ) &&
0a6d8768 747 (!gMC->IsTrackDisappeared())) {
d3f347ff 748
fe4da5cc 749 // Inside a sensitive volume?
82bbf98a 750 iIdSens = gMC->CurrentVolID(icSens);
751 if (iIdSens == fIdSens) {
752
753 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
754 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
d3f347ff 755
756 // Calculate the energy of the delta-electrons
757 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
758 eDelta = TMath::Max(eDelta,0.0);
759
760 // The number of secondary electrons created
761 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
762
82bbf98a 763 // The hit coordinates and charge
764 gMC->TrackPosition(pos);
765 hits[0] = pos[0];
766 hits[1] = pos[1];
767 hits[2] = pos[2];
768 hits[3] = qTot;
d3f347ff 769
82bbf98a 770 // The sector number
771 if (iIdSpace == fIdSpace1)
772 vol[0] = secMap1[icSpace-1];
773 else if (iIdSpace == fIdSpace2)
774 vol[0] = secMap2[icSpace-1];
775 else if (iIdSpace == fIdSpace3)
776 vol[0] = secMap3[icSpace-1];
777
778 // The chamber number
d3f347ff 779 // 1: outer left
82bbf98a 780 // 2: middle left
d3f347ff 781 // 3: inner
82bbf98a 782 // 4: middle right
d3f347ff 783 // 5: outer right
82bbf98a 784 if (iIdChamber == fIdChamber1)
785 vol[1] = (hits[2] < 0 ? 1 : 5);
786 else if (iIdChamber == fIdChamber2)
787 vol[1] = (hits[2] < 0 ? 2 : 4);
788 else if (iIdChamber == fIdChamber3)
789 vol[1] = 3;
d3f347ff 790
82bbf98a 791 // The plane number
792 vol[2] = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6;
fe4da5cc 793
d3f347ff 794 // Check on selected volumes
795 Int_t addthishit = 1;
796 if (fSensSelect) {
797 if ((fSensPlane) && (vol[2] != fSensPlane )) addthishit = 0;
798 if ((fSensChamber) && (vol[1] != fSensChamber)) addthishit = 0;
799 if ((fSensSector) && (vol[0] != fSensSector )) addthishit = 0;
800 }
801
82bbf98a 802 // Add this hit
d3f347ff 803 if (addthishit) {
804
d3f347ff 805 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack(),vol,hits);
806
807 // The energy loss according to Bethe Bloch
cfce8870 808 gMC->TrackMomentum(mom);
0a6d8768 809 pTot = mom.Rho();
cfce8870 810 iPid = gMC->TrackPid();
d3f347ff 811 if ( (iPid > 3) ||
812 ((iPid <= 3) && (pTot < kPTotMax))) {
cfce8870 813 aMass = gMC->TrackMass();
d3f347ff 814 betaGamma = pTot / aMass;
815 pp = kPrim * BetheBloch(betaGamma);
816 // Take charge > 1 into account
cfce8870 817 charge = gMC->TrackCharge();
d3f347ff 818 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
819 }
820 // Electrons above 20 Mev/c are at the plateau
821 else {
822 pp = kPrim * kPlateau;
823 }
fe4da5cc 824
d3f347ff 825 // Calculate the maximum step size for the next tracking step
826 if (pp > 0) {
827 do
cfce8870 828 gMC->Rndm(random,1);
d3f347ff 829 while ((random[0] == 1.) || (random[0] == 0.));
cfce8870 830 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
d3f347ff 831 }
832
fe4da5cc 833 }
fe4da5cc 834 else {
d3f347ff 835 // set step size to maximal value
cfce8870 836 gMC->SetMaxStep(kBig);
fe4da5cc 837 }
d3f347ff 838
fe4da5cc 839 }
d3f347ff 840
841 }
842
843}
844
845//_____________________________________________________________________________
846Double_t AliTRDv2::BetheBloch(Double_t bg)
847{
848 //
849 // Parametrization of the Bethe-Bloch-curve
850 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
851 //
852
d3f347ff 853 // This parameters have been adjusted to averaged values from GEANT
854 const Double_t kP1 = 7.17960e-02;
855 const Double_t kP2 = 8.54196;
856 const Double_t kP3 = 1.38065e-06;
857 const Double_t kP4 = 5.30972;
858 const Double_t kP5 = 2.83798;
859
99d5402e 860 // This parameters have been adjusted to Xe-data found in:
861 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
862 //const Double_t kP1 = 0.76176E-1;
863 //const Double_t kP2 = 10.632;
864 //const Double_t kP3 = 3.17983E-6;
865 //const Double_t kP4 = 1.8631;
866 //const Double_t kP5 = 1.9479;
867
d3f347ff 868 if (bg > 0) {
869 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
870 Double_t aa = TMath::Power(yy,kP4);
871 Double_t bb = TMath::Power((1./bg),kP5);
872 bb = TMath::Log(kP3 + bb);
873 return ((kP2 - aa - bb)*kP1 / aa);
fe4da5cc 874 }
d3f347ff 875 else
876 return 0;
877
878}
879
880//_____________________________________________________________________________
6fe53707 881Double_t Ermilova(Double_t *x, Double_t *)
d3f347ff 882{
883 //
99d5402e 884 // Calculates the delta-ray energy distribution according to Ermilova.
d3f347ff 885 // Logarithmic scale !
886 //
887
888 Double_t energy;
889 Double_t dpos;
890 Double_t dnde;
891
892 Int_t pos1, pos2;
893
894 const Int_t nV = 31;
895
896 Float_t vxe[nV] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
897 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
898 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
899 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
900 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
901 , 9.4727, 9.9035,10.3735,10.5966,10.8198
902 ,11.5129 };
903
904 Float_t vye[nV] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
905 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
906 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
907 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
908 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
909 , 0.04 , 0.023, 0.015, 0.011, 0.01
910 , 0.004 };
911
912 energy = x[0];
913
914 // Find the position
915 pos1 = pos2 = 0;
916 dpos = 0;
917 do {
918 dpos = energy - vxe[pos2++];
919 }
920 while (dpos > 0);
921 pos2--;
922 if (pos2 > nV) pos2 = nV;
923 pos1 = pos2 - 1;
924
925 // Differentiate between the sampling points
926 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
927
928 return dnde;
929
fe4da5cc 930}