1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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 **************************************************************************/
18 Revision 1.35 2002/10/14 14:57:44 hristov
19 Merging the VirtualMC branch to the main development branch (HEAD)
21 Revision 1.33.6.2 2002/07/24 10:09:31 alibrary
24 Revision 1.34 2002/06/13 08:11:56 cblume
25 Add the track references
27 Revision 1.33 2002/02/20 14:01:40 hristov
28 Compare a TString with a string, otherwise the conversion cannot be done on Sun
30 Revision 1.32 2002/02/13 16:58:37 cblume
31 Bug fix reported by Jiri. Make atoi input zero terminated in StepManager()
33 Revision 1.31 2002/02/11 14:25:27 cblume
34 Geometry update, compressed hit structure
36 Revision 1.30 2001/05/21 16:45:47 hristov
37 Last minute changes (C.Blume)
39 Revision 1.29 2001/05/16 14:57:28 alibrary
40 New files for folders and Stack
42 Revision 1.28 2001/05/07 08:03:22 cblume
43 Generate also hits in the amplification region
45 Revision 1.27 2001/03/30 14:40:15 cblume
46 Update of the digitization parameter
48 Revision 1.26 2000/11/30 17:38:08 cblume
49 Changes to get in line with new STEER and EVGEN
51 Revision 1.25 2000/11/15 14:30:16 cblume
52 Fixed bug in calculating detector no. of extra hit
54 Revision 1.24 2000/11/10 14:58:36 cblume
55 Introduce additional hit with amplitude 0 at the chamber borders
57 Revision 1.23 2000/11/01 14:53:21 cblume
58 Merge with TRD-develop
60 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
63 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
66 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
67 Replace include files by forward declarations
69 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
70 Include TR photon generation and adapt to new AliTRDhit
72 Revision 1.22 2000/06/27 13:08:50 cblume
73 Changed to Copy(TObject &A) to appease the HP-compiler
75 Revision 1.21 2000/06/09 11:10:07 cblume
76 Compiler warnings and coding conventions, next round
78 Revision 1.20 2000/06/08 18:32:58 cblume
79 Make code compliant to coding conventions
81 Revision 1.19 2000/06/07 16:27:32 cblume
82 Try to remove compiler warnings on Sun and HP
84 Revision 1.18 2000/05/08 16:17:27 cblume
87 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
88 Made inline function non-virtual. Bug fix in setting sensitive chamber
90 Revision 1.17 2000/02/28 19:10:26 cblume
91 Include the new TRD classes
93 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
94 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
96 Revision 1.16 1999/11/05 22:50:28 fca
97 Do not use Atan, removed from ROOT too
99 Revision 1.15 1999/11/02 17:20:19 fca
100 initialise nbytes before using it
102 Revision 1.14 1999/11/02 17:15:54 fca
103 Correct ansi scoping not accepted by HP compilers
105 Revision 1.13 1999/11/02 17:14:51 fca
106 Correct ansi scoping not accepted by HP compilers
108 Revision 1.12 1999/11/02 16:35:56 fca
109 New version of TRD introduced
111 Revision 1.11 1999/11/01 20:41:51 fca
112 Added protections against using the wrong version of FRAME
114 Revision 1.10 1999/09/29 09:24:35 fca
115 Introduction of the Copyright and cvs Log
119 ///////////////////////////////////////////////////////////////////////////////
121 // Transition Radiation Detector version 1 -- slow simulator //
125 <img src="picts/AliTRDfullClass.gif">
130 ///////////////////////////////////////////////////////////////////////////////
138 #include <TLorentzVector.h>
141 #include "AliConst.h"
143 #include "AliTRDv1.h"
144 #include "AliTRDhit.h"
145 #include "AliTRDmatrix.h"
146 #include "AliTRDgeometry.h"
147 #include "AliTRDsim.h"
151 //_____________________________________________________________________________
152 AliTRDv1::AliTRDv1():AliTRD()
155 // Default constructor
162 fSensSectorRange = 0;
169 //_____________________________________________________________________________
170 AliTRDv1::AliTRDv1(const char *name, const char *title)
174 // Standard constructor for Transition Radiation Detector version 1
181 fSensSectorRange = 0;
186 SetBufferSize(128000);
190 //_____________________________________________________________________________
191 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
197 ((AliTRDv1 &) trd).Copy(*this);
201 //_____________________________________________________________________________
202 AliTRDv1::~AliTRDv1()
205 // AliTRDv1 destructor
208 if (fDeltaE) delete fDeltaE;
213 //_____________________________________________________________________________
214 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
217 // Assignment operator
220 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
225 //_____________________________________________________________________________
226 void AliTRDv1::Copy(TObject &trd)
232 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
233 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
234 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
235 ((AliTRDv1 &) trd).fSensSector = fSensSector;
236 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
238 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
239 fTR->Copy(*((AliTRDv1 &) trd).fTR);
243 //_____________________________________________________________________________
244 void AliTRDv1::CreateGeometry()
247 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
248 // This version covers the full azimuth.
251 // Check that FRAME is there otherwise we have no place where to put the TRD
252 AliModule* frame = gAlice->GetModule("FRAME");
255 // Define the chambers
256 AliTRD::CreateGeometry();
260 //_____________________________________________________________________________
261 void AliTRDv1::CreateMaterials()
264 // Create materials for the Transition Radiation Detector version 1
267 AliTRD::CreateMaterials();
271 //_____________________________________________________________________________
272 void AliTRDv1::CreateTRhit(Int_t det)
275 // Creates an electron cluster from a TR photon.
276 // The photon is assumed to be created a the end of the radiator. The
277 // distance after which it deposits its energy takes into account the
278 // absorbtion of the entrance window and of the gas mixture in drift
283 const Int_t kPdgElectron = 11;
286 const Float_t kWion = 22.04;
288 // Maximum number of TR photons per track
289 const Int_t kNTR = 50;
291 TLorentzVector mom, pos;
293 // Create TR at the entrance of the chamber
294 if (gMC->IsTrackEntering()) {
296 // Create TR only for electrons
297 Int_t iPdg = gMC->TrackPid();
298 if (TMath::Abs(iPdg) != kPdgElectron) return;
304 gMC->TrackMomentum(mom);
305 Float_t pTot = mom.Rho();
306 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
308 printf("AliTRDv1::CreateTRhit -- ");
309 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
313 // Loop through the TR photons
314 for (Int_t iTR = 0; iTR < nTR; iTR++) {
316 Float_t energyMeV = eTR[iTR] * 0.001;
317 Float_t energyeV = eTR[iTR] * 1000.0;
318 Float_t absLength = 0;
321 // Take the absorbtion in the entrance window into account
322 Double_t muMy = fTR->GetMuMy(energyMeV);
323 sigma = muMy * fFoilDensity;
324 absLength = gRandom->Exp(sigma);
325 if (absLength < AliTRDgeometry::MyThick()) continue;
327 // The absorbtion cross sections in the drift gas
329 // Gas-mixture (Xe/CO2)
330 Double_t muXe = fTR->GetMuXe(energyMeV);
331 Double_t muCO = fTR->GetMuCO(energyMeV);
332 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
335 // Gas-mixture (Xe/Isobutane)
336 Double_t muXe = fTR->GetMuXe(energyMeV);
337 Double_t muBu = fTR->GetMuBu(energyMeV);
338 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
341 // The distance after which the energy of the TR photon
343 absLength = gRandom->Exp(sigma);
344 if (absLength > AliTRDgeometry::DrThick()) continue;
346 // The position of the absorbtion
348 gMC->TrackPosition(pos);
349 posHit[0] = pos[0] + mom[0] / pTot * absLength;
350 posHit[1] = pos[1] + mom[1] / pTot * absLength;
351 posHit[2] = pos[2] + mom[2] / pTot * absLength;
354 Int_t q = ((Int_t) (energyeV / kWion));
356 // Add the hit to the array. TR photon hits are marked
357 // by negative charge
358 AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
366 //_____________________________________________________________________________
367 void AliTRDv1::Init()
370 // Initialise Transition Radiation Detector after geometry has been built.
375 if(fDebug) printf("%s: Slow simulator\n",ClassName());
378 printf(" Only plane %d is sensitive\n",fSensPlane);
379 if (fSensChamber >= 0)
380 printf(" Only chamber %d is sensitive\n",fSensChamber);
381 if (fSensSector >= 0) {
382 Int_t sens1 = fSensSector;
383 Int_t sens2 = fSensSector + fSensSectorRange;
384 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
385 * AliTRDgeometry::Nsect();
386 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
390 printf("%s: TR simulation on\n",ClassName());
392 printf("%s: TR simulation off\n",ClassName());
395 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
396 const Float_t kPoti = 12.1;
397 // Maximum energy (50 keV);
398 const Float_t kEend = 50000.0;
399 // Ermilova distribution for the delta-ray spectrum
400 Float_t poti = TMath::Log(kPoti);
401 Float_t eEnd = TMath::Log(kEend);
402 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
405 printf("%s: ",ClassName());
406 for (Int_t i = 0; i < 80; i++) printf("*");
412 //_____________________________________________________________________________
413 AliTRDsim *AliTRDv1::CreateTR()
416 // Enables the simulation of TR
419 fTR = new AliTRDsim();
424 //_____________________________________________________________________________
425 void AliTRDv1::SetSensPlane(Int_t iplane)
428 // Defines the hit-sensitive plane (0-5)
431 if ((iplane < 0) || (iplane > 5)) {
432 printf("Wrong input value: %d\n",iplane);
433 printf("Use standard setting\n");
444 //_____________________________________________________________________________
445 void AliTRDv1::SetSensChamber(Int_t ichamber)
448 // Defines the hit-sensitive chamber (0-4)
451 if ((ichamber < 0) || (ichamber > 4)) {
452 printf("Wrong input value: %d\n",ichamber);
453 printf("Use standard setting\n");
460 fSensChamber = ichamber;
464 //_____________________________________________________________________________
465 void AliTRDv1::SetSensSector(Int_t isector)
468 // Defines the hit-sensitive sector (0-17)
471 SetSensSector(isector,1);
475 //_____________________________________________________________________________
476 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
479 // Defines a range of hit-sensitive sectors. The range is defined by
480 // <isector> (0-17) as the starting point and <nsector> as the number
481 // of sectors to be included.
484 if ((isector < 0) || (isector > 17)) {
485 printf("Wrong input value <isector>: %d\n",isector);
486 printf("Use standard setting\n");
488 fSensSectorRange = 0;
493 if ((nsector < 1) || (nsector > 18)) {
494 printf("Wrong input value <nsector>: %d\n",nsector);
495 printf("Use standard setting\n");
497 fSensSectorRange = 0;
503 fSensSector = isector;
504 fSensSectorRange = nsector;
508 //_____________________________________________________________________________
509 void AliTRDv1::StepManager()
512 // Slow simulator. Every charged track produces electron cluster as hits
513 // along its path across the drift volume. The step size is set acording
514 // to Bethe-Bloch. The energy distribution of the delta electrons follows
515 // a spectrum taken from Ermilova et al.
532 Double_t betaGamma, pp;
535 Bool_t drRegion = kFALSE;
536 Bool_t amRegion = kFALSE;
539 TString cIdSensDr = "J";
540 TString cIdSensAm = "K";
541 Char_t cIdChamber[3];
544 TLorentzVector pos, mom;
546 const Int_t kNplan = AliTRDgeometry::Nplan();
547 const Double_t kBig = 1.0E+12;
550 const Float_t kWion = 22.04;
551 // Maximum momentum for e+ e- g
552 const Float_t kPTotMaxEl = 0.002;
553 // Minimum energy for the step size adjustment
554 const Float_t kEkinMinStep = 1.0e-5;
555 // Plateau value of the energy-loss for electron in xenon
556 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
557 //const Double_t kPlateau = 1.70;
558 // the averaged value (26/3/99)
559 const Float_t kPlateau = 1.55;
560 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
561 const Float_t kPrim = 48.0;
562 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
563 const Float_t kPoti = 12.1;
566 const Int_t kPdgElectron = 11;
568 // Set the maximum step size to a very large number for all
569 // neutral particles and those outside the driftvolume
570 gMC->SetMaxStep(kBig);
572 // Use only charged tracks
573 if (( gMC->TrackCharge() ) &&
574 (!gMC->IsTrackStop() ) &&
575 (!gMC->IsTrackDisappeared())) {
577 // Inside a sensitive volume?
580 cIdCurrent = gMC->CurrentVolName();
581 if (cIdSensDr == cIdCurrent[1]) {
584 if (cIdSensAm == cIdCurrent[1]) {
587 if (drRegion || amRegion) {
589 // The hit coordinates and charge
590 gMC->TrackPosition(pos);
595 // The sector number (0 - 17)
596 // The numbering goes clockwise and starts at y = 0
597 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
602 sec = ((Int_t) (phi / 20));
604 // The plane and chamber number
605 cIdChamber[0] = cIdCurrent[2];
606 cIdChamber[1] = cIdCurrent[3];
607 Int_t idChamber = atoi(cIdChamber);
608 cha = ((Int_t) idChamber / kNplan);
609 pla = ((Int_t) idChamber % kNplan);
611 // Check on selected volumes
612 Int_t addthishit = 1;
614 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
615 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
616 if (fSensSector >= 0) {
617 Int_t sens1 = fSensSector;
618 Int_t sens2 = fSensSector + fSensSectorRange;
619 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
620 * AliTRDgeometry::Nsect();
622 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
625 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
633 // The detector number
634 det = fGeometry->GetDetector(pla,cha,sec);
636 // Special hits and TR photons only in the drift region
639 // Create a track reference at the entrance and
640 // exit of each chamber that contain the
641 // momentum components of the particle
642 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
643 gMC->TrackMomentum(mom);
644 AddTrackReference(gAlice->CurrentTrack(),mom,pos);
647 // Create the hits from TR photons
648 if (fTR) CreateTRhit(det);
652 // Calculate the energy of the delta-electrons
653 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
654 eDelta = TMath::Max(eDelta,0.0);
656 // The number of secondary electrons created
657 qTot = ((Int_t) (eDelta / kWion) + 1);
659 // Create a new dEdx hit
661 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
664 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
667 // Calculate the maximum step size for the next tracking step
668 // Produce only one hit if Ekin is below cutoff
669 aMass = gMC->TrackMass();
670 if ((gMC->Etot() - aMass) > kEkinMinStep) {
672 // The energy loss according to Bethe Bloch
673 iPdg = TMath::Abs(gMC->TrackPid());
674 if ( (iPdg != kPdgElectron) ||
675 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
676 gMC->TrackMomentum(mom);
678 betaGamma = pTot / aMass;
679 pp = kPrim * BetheBloch(betaGamma);
680 // Take charge > 1 into account
681 charge = gMC->TrackCharge();
682 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
684 // Electrons above 20 Mev/c are at the plateau
686 pp = kPrim * kPlateau;
691 gMC->GetRandom()->RndmArray(1, random);
692 while ((random[0] == 1.) || (random[0] == 0.));
693 stepSize = - TMath::Log(random[0]) / pp;
694 gMC->SetMaxStep(stepSize);
707 //_____________________________________________________________________________
708 Double_t AliTRDv1::BetheBloch(Double_t bg)
711 // Parametrization of the Bethe-Bloch-curve
712 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
715 // This parameters have been adjusted to averaged values from GEANT
716 const Double_t kP1 = 7.17960e-02;
717 const Double_t kP2 = 8.54196;
718 const Double_t kP3 = 1.38065e-06;
719 const Double_t kP4 = 5.30972;
720 const Double_t kP5 = 2.83798;
722 // This parameters have been adjusted to Xe-data found in:
723 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
724 //const Double_t kP1 = 0.76176E-1;
725 //const Double_t kP2 = 10.632;
726 //const Double_t kP3 = 3.17983E-6;
727 //const Double_t kP4 = 1.8631;
728 //const Double_t kP5 = 1.9479;
730 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
731 const Double_t kBgMin = 0.8;
732 const Double_t kBBMax = 6.83298;
733 //const Double_t kBgMin = 0.6;
734 //const Double_t kBBMax = 17.2809;
735 //const Double_t kBgMin = 0.4;
736 //const Double_t kBBMax = 82.0;
739 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
740 Double_t aa = TMath::Power(yy,kP4);
741 Double_t bb = TMath::Power((1./bg),kP5);
742 bb = TMath::Log(kP3 + bb);
743 return ((kP2 - aa - bb)*kP1 / aa);
751 //_____________________________________________________________________________
752 Double_t Ermilova(Double_t *x, Double_t *)
755 // Calculates the delta-ray energy distribution according to Ermilova.
756 // Logarithmic scale !
765 const Int_t kNv = 31;
767 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
768 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
769 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
770 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
771 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
772 , 9.4727, 9.9035,10.3735,10.5966,10.8198
775 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
776 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
777 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
778 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
779 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
780 , 0.04 , 0.023, 0.015, 0.011, 0.01
789 dpos = energy - vxe[pos2++];
793 if (pos2 > kNv) pos2 = kNv - 1;
796 // Differentiate between the sampling points
797 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);