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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$Log$
18Revision 1.21 2000/06/09 11:10:07 cblume
19Compiler warnings and coding conventions, next round
20
21Revision 1.20 2000/06/08 18:32:58 cblume
22Make code compliant to coding conventions
23
24Revision 1.19 2000/06/07 16:27:32 cblume
25Try to remove compiler warnings on Sun and HP
26
27Revision 1.18 2000/05/08 16:17:27 cblume
28Merge TRD-develop
29
30Revision 1.17.2.1 2000/05/08 14:59:16 cblume
31Made inline function non-virtual. Bug fix in setting sensitive chamber
32
33Revision 1.17 2000/02/28 19:10:26 cblume
34Include the new TRD classes
35
36Revision 1.16.4.1 2000/02/28 18:04:35 cblume
37Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
38
39Revision 1.16 1999/11/05 22:50:28 fca
40Do not use Atan, removed from ROOT too
41
42Revision 1.15 1999/11/02 17:20:19 fca
43initialise nbytes before using it
44
45Revision 1.14 1999/11/02 17:15:54 fca
46Correct ansi scoping not accepted by HP compilers
47
48Revision 1.13 1999/11/02 17:14:51 fca
49Correct ansi scoping not accepted by HP compilers
50
51Revision 1.12 1999/11/02 16:35:56 fca
52New version of TRD introduced
53
54Revision 1.11 1999/11/01 20:41:51 fca
55Added protections against using the wrong version of FRAME
56
57Revision 1.10 1999/09/29 09:24:35 fca
58Introduction of the Copyright and cvs Log
59
60*/
61
62///////////////////////////////////////////////////////////////////////////////
63// //
64// Transition Radiation Detector version 2 -- slow simulator //
65// //
66//Begin_Html
67/*
68<img src="picts/AliTRDfullClass.gif">
69*/
70//End_Html
71// //
72// //
73///////////////////////////////////////////////////////////////////////////////
74
75#include <TMath.h>
76#include <TVector.h>
77#include <TRandom.h>
78
79#include "AliRun.h"
80#include "AliMC.h"
81#include "AliConst.h"
82
83#include "AliTRDv1.h"
84#include "AliTRDmatrix.h"
85#include "AliTRDgeometry.h"
86
87ClassImp(AliTRDv1)
88
89
90//_____________________________________________________________________________
91AliTRDv1::AliTRDv1():AliTRD()
92{
93 //
94 // Default constructor
95 //
96
97 fIdSens = 0;
98
99 fIdChamber1 = 0;
100 fIdChamber2 = 0;
101 fIdChamber3 = 0;
102
103 fSensSelect = 0;
104 fSensPlane = -1;
105 fSensChamber = -1;
106 fSensSector = -1;
107 fSensSectorRange = 0;
108
109 fDeltaE = NULL;
110
111}
112
113//_____________________________________________________________________________
114AliTRDv1::AliTRDv1(const char *name, const char *title)
115 :AliTRD(name, title)
116{
117 //
118 // Standard constructor for Transition Radiation Detector version 1
119 //
120
121 fIdSens = 0;
122
123 fIdChamber1 = 0;
124 fIdChamber2 = 0;
125 fIdChamber3 = 0;
126
127 fSensSelect = 0;
128 fSensPlane = -1;
129 fSensChamber = -1;
130 fSensSector = -1;
131 fSensSectorRange = 0;
132
133 fDeltaE = NULL;
134
135 SetBufferSize(128000);
136
137}
138
139//_____________________________________________________________________________
140AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
141{
142 //
143 // Copy constructor
144 //
145
146 ((AliTRDv1 &) trd).Copy(*this);
147
148}
149
150//_____________________________________________________________________________
151AliTRDv1::~AliTRDv1()
152{
153 //
154 // AliTRDv1 destructor
155 //
156
157 if (fDeltaE) delete fDeltaE;
158
159}
160
161//_____________________________________________________________________________
162AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
163{
164 //
165 // Assignment operator
166 //
167
168 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
169 return *this;
170
171}
172
173//_____________________________________________________________________________
174void AliTRDv1::Copy(TObject &trd)
175{
176 //
177 // Copy function
178 //
179
180 ((AliTRDv1 &) trd).fIdSens = fIdSens;
181
182 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
183 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
184 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
185
186 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
187 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
188 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
189 ((AliTRDv1 &) trd).fSensSector = fSensSector;
190 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
191
192 ((AliTRDv1 &) trd).fDeltaE = NULL;
193
194}
195
196//_____________________________________________________________________________
197void AliTRDv1::CreateGeometry()
198{
199 //
200 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
201 // This version covers the full azimuth.
202 //
203
204 // Check that FRAME is there otherwise we have no place where to put the TRD
205 AliModule* frame = gAlice->GetModule("FRAME");
206 if (!frame) return;
207
208 // Define the chambers
209 AliTRD::CreateGeometry();
210
211}
212
213//_____________________________________________________________________________
214void AliTRDv1::CreateMaterials()
215{
216 //
217 // Create materials for the Transition Radiation Detector version 1
218 //
219
220 AliTRD::CreateMaterials();
221
222}
223
224//_____________________________________________________________________________
225void AliTRDv1::Init()
226{
227 //
228 // Initialise Transition Radiation Detector after geometry has been built.
229 //
230
231 AliTRD::Init();
232
233 printf(" Slow simulator\n\n");
234 if (fSensSelect) {
235 if (fSensPlane >= 0)
236 printf(" Only plane %d is sensitive\n",fSensPlane);
237 if (fSensChamber >= 0)
238 printf(" Only chamber %d is sensitive\n",fSensChamber);
239 if (fSensSector >= 0) {
240 Int_t sens1 = fSensSector;
241 Int_t sens2 = fSensSector + fSensSectorRange;
242 sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
243 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
244 }
245 }
246 printf("\n");
247
248 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
249 const Float_t kPoti = 12.1;
250 // Maximum energy (50 keV);
251 const Float_t kEend = 50000.0;
252 // Ermilova distribution for the delta-ray spectrum
253 Float_t poti = TMath::Log(kPoti);
254 Float_t eEnd = TMath::Log(kEend);
255 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
256
257 // Identifier of the sensitive volume (drift region)
258 fIdSens = gMC->VolId("UL05");
259
260 // Identifier of the TRD-driftchambers
261 fIdChamber1 = gMC->VolId("UCIO");
262 fIdChamber2 = gMC->VolId("UCIM");
263 fIdChamber3 = gMC->VolId("UCII");
264
265 for (Int_t i = 0; i < 80; i++) printf("*");
266 printf("\n");
267
268}
269
270//_____________________________________________________________________________
271void AliTRDv1::SetSensPlane(Int_t iplane)
272{
273 //
274 // Defines the hit-sensitive plane (0-5)
275 //
276
277 if ((iplane < 0) || (iplane > 5)) {
278 printf("Wrong input value: %d\n",iplane);
279 printf("Use standard setting\n");
280 fSensPlane = -1;
281 fSensSelect = 0;
282 return;
283 }
284
285 fSensSelect = 1;
286 fSensPlane = iplane;
287
288}
289
290//_____________________________________________________________________________
291void AliTRDv1::SetSensChamber(Int_t ichamber)
292{
293 //
294 // Defines the hit-sensitive chamber (0-4)
295 //
296
297 if ((ichamber < 0) || (ichamber > 4)) {
298 printf("Wrong input value: %d\n",ichamber);
299 printf("Use standard setting\n");
300 fSensChamber = -1;
301 fSensSelect = 0;
302 return;
303 }
304
305 fSensSelect = 1;
306 fSensChamber = ichamber;
307
308}
309
310//_____________________________________________________________________________
311void AliTRDv1::SetSensSector(Int_t isector)
312{
313 //
314 // Defines the hit-sensitive sector (0-17)
315 //
316
317 SetSensSector(isector,1);
318
319}
320
321//_____________________________________________________________________________
322void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
323{
324 //
325 // Defines a range of hit-sensitive sectors. The range is defined by
326 // <isector> (0-17) as the starting point and <nsector> as the number
327 // of sectors to be included.
328 //
329
330 if ((isector < 0) || (isector > 17)) {
331 printf("Wrong input value <isector>: %d\n",isector);
332 printf("Use standard setting\n");
333 fSensSector = -1;
334 fSensSectorRange = 0;
335 fSensSelect = 0;
336 return;
337 }
338
339 if ((nsector < 1) || (nsector > 18)) {
340 printf("Wrong input value <nsector>: %d\n",nsector);
341 printf("Use standard setting\n");
342 fSensSector = -1;
343 fSensSectorRange = 0;
344 fSensSelect = 0;
345 return;
346 }
347
348 fSensSelect = 1;
349 fSensSector = isector;
350 fSensSectorRange = nsector;
351
352}
353
354//_____________________________________________________________________________
355void AliTRDv1::StepManager()
356{
357 //
358 // Slow simulator. Every charged track produces electron cluster as hits
359 // along its path across the drift volume. The step size is set acording
360 // to Bethe-Bloch. The energy distribution of the delta electrons follows
361 // a spectrum taken from Ermilova et al.
362 //
363
364 Int_t iIdSens, icSens;
365 Int_t iIdSpace, icSpace;
366 Int_t iIdChamber, icChamber;
367 Int_t pla = 0;
368 Int_t cha = 0;
369 Int_t sec = 0;
370 Int_t iPdg;
371
372 Int_t det[1];
373
374 Float_t hits[4];
375 Float_t random[1];
376 Float_t charge;
377 Float_t aMass;
378
379 Double_t pTot;
380 Double_t qTot;
381 Double_t eDelta;
382 Double_t betaGamma, pp;
383
384 TLorentzVector pos, mom;
385 TClonesArray &lhits = *fHits;
386
387 const Double_t kBig = 1.0E+12;
388
389 // Ionization energy
390 const Float_t kWion = 22.04;
391 // Maximum energy for e+ e- g for the step-size calculation
392 const Float_t kPTotMax = 0.002;
393 // Plateau value of the energy-loss for electron in xenon
394 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
395 //const Double_t kPlateau = 1.70;
396 // the averaged value (26/3/99)
397 const Float_t kPlateau = 1.55;
398 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
399 const Float_t kPrim = 48.0;
400 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
401 const Float_t kPoti = 12.1;
402
403 // PDG code electron
404 const Int_t kPdgElectron = 11;
405
406 // Set the maximum step size to a very large number for all
407 // neutral particles and those outside the driftvolume
408 gMC->SetMaxStep(kBig);
409
410 // Use only charged tracks
411 if (( gMC->TrackCharge() ) &&
412 (!gMC->IsTrackStop() ) &&
413 (!gMC->IsTrackDisappeared())) {
414
415 // Inside a sensitive volume?
416 iIdSens = gMC->CurrentVolID(icSens);
417 if (iIdSens == fIdSens) {
418
419 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
420 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
421
422 // Calculate the energy of the delta-electrons
423 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
424 eDelta = TMath::Max(eDelta,0.0);
425
426 // The number of secondary electrons created
427 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
428
429 // The hit coordinates and charge
430 gMC->TrackPosition(pos);
431 hits[0] = pos[0];
432 hits[1] = pos[1];
433 hits[2] = pos[2];
434 hits[3] = qTot;
435
436 // The sector number (0 - 17)
437 // The numbering goes clockwise and starts at y = 0
438 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
439 if (phi < 90.)
440 phi = phi + 270.;
441 else
442 phi = phi - 90.;
443 sec = ((Int_t) (phi / 20));
444
445 // The chamber number
446 // 0: outer left
447 // 1: middle left
448 // 2: inner
449 // 3: middle right
450 // 4: outer right
451 if (iIdChamber == fIdChamber1)
452 cha = (hits[2] < 0 ? 0 : 4);
453 else if (iIdChamber == fIdChamber2)
454 cha = (hits[2] < 0 ? 1 : 3);
455 else if (iIdChamber == fIdChamber3)
456 cha = 2;
457
458 // The plane number
459 // The numbering starts at the innermost plane
460 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
461
462 // Check on selected volumes
463 Int_t addthishit = 1;
464 if (fSensSelect) {
465 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
466 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
467 if (fSensSector >= 0) {
468 Int_t sens1 = fSensSector;
469 Int_t sens2 = fSensSector + fSensSectorRange;
470 sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
471 if (sens1 < sens2) {
472 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
473 }
474 else {
475 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
476 }
477 }
478 }
479
480 // Add this hit
481 if (addthishit) {
482
483 det[0] = fGeometry->GetDetector(pla,cha,sec);
484 new(lhits[fNhits++]) AliTRDhit(fIshunt
485 ,gAlice->CurrentTrack()
486 ,det
487 ,hits);
488
489 // The energy loss according to Bethe Bloch
490 gMC->TrackMomentum(mom);
491 pTot = mom.Rho();
492 iPdg = TMath::Abs(gMC->TrackPid());
493 if ( (iPdg != kPdgElectron) ||
494 ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
495 aMass = gMC->TrackMass();
496 betaGamma = pTot / aMass;
497 pp = kPrim * BetheBloch(betaGamma);
498 // Take charge > 1 into account
499 charge = gMC->TrackCharge();
500 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
501 }
502 // Electrons above 20 Mev/c are at the plateau
503 else {
504 pp = kPrim * kPlateau;
505 }
506
507 // Calculate the maximum step size for the next tracking step
508 if (pp > 0) {
509 do
510 gMC->Rndm(random,1);
511 while ((random[0] == 1.) || (random[0] == 0.));
512 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
513 }
514
515 }
516 else {
517 // set step size to maximal value
518 gMC->SetMaxStep(kBig);
519 }
520
521 }
522
523 }
524
525}
526
527//_____________________________________________________________________________
528Double_t AliTRDv1::BetheBloch(Double_t bg)
529{
530 //
531 // Parametrization of the Bethe-Bloch-curve
532 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
533 //
534
535 // This parameters have been adjusted to averaged values from GEANT
536 const Double_t kP1 = 7.17960e-02;
537 const Double_t kP2 = 8.54196;
538 const Double_t kP3 = 1.38065e-06;
539 const Double_t kP4 = 5.30972;
540 const Double_t kP5 = 2.83798;
541
542 // This parameters have been adjusted to Xe-data found in:
543 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
544 //const Double_t kP1 = 0.76176E-1;
545 //const Double_t kP2 = 10.632;
546 //const Double_t kP3 = 3.17983E-6;
547 //const Double_t kP4 = 1.8631;
548 //const Double_t kP5 = 1.9479;
549
550 if (bg > 0) {
551 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
552 Double_t aa = TMath::Power(yy,kP4);
553 Double_t bb = TMath::Power((1./bg),kP5);
554 bb = TMath::Log(kP3 + bb);
555 return ((kP2 - aa - bb)*kP1 / aa);
556 }
557 else
558 return 0;
559
560}
561
562//_____________________________________________________________________________
563Double_t Ermilova(Double_t *x, Double_t *)
564{
565 //
566 // Calculates the delta-ray energy distribution according to Ermilova.
567 // Logarithmic scale !
568 //
569
570 Double_t energy;
571 Double_t dpos;
572 Double_t dnde;
573
574 Int_t pos1, pos2;
575
576 const Int_t kNv = 31;
577
578 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
579 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
580 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
581 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
582 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
583 , 9.4727, 9.9035,10.3735,10.5966,10.8198
584 ,11.5129 };
585
586 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
587 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
588 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
589 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
590 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
591 , 0.04 , 0.023, 0.015, 0.011, 0.01
592 , 0.004 };
593
594 energy = x[0];
595
596 // Find the position
597 pos1 = pos2 = 0;
598 dpos = 0;
599 do {
600 dpos = energy - vxe[pos2++];
601 }
602 while (dpos > 0);
603 pos2--;
604 if (pos2 > kNv) pos2 = kNv;
605 pos1 = pos2 - 1;
606
607 // Differentiate between the sampling points
608 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);
609
610 return dnde;
611
612}