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 1.32 2002/02/13 16:58:37 cblume
19 Bug fix reported by Jiri. Make atoi input zero terminated in StepManager()
21 Revision 1.31 2002/02/11 14:25:27 cblume
22 Geometry update, compressed hit structure
24 Revision 1.30 2001/05/21 16:45:47 hristov
25 Last minute changes (C.Blume)
27 Revision 1.29 2001/05/16 14:57:28 alibrary
28 New files for folders and Stack
30 Revision 1.28 2001/05/07 08:03:22 cblume
31 Generate also hits in the amplification region
33 Revision 1.27 2001/03/30 14:40:15 cblume
34 Update of the digitization parameter
36 Revision 1.26 2000/11/30 17:38:08 cblume
37 Changes to get in line with new STEER and EVGEN
39 Revision 1.25 2000/11/15 14:30:16 cblume
40 Fixed bug in calculating detector no. of extra hit
42 Revision 1.24 2000/11/10 14:58:36 cblume
43 Introduce additional hit with amplitude 0 at the chamber borders
45 Revision 1.23 2000/11/01 14:53:21 cblume
46 Merge with TRD-develop
48 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
51 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
54 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
55 Replace include files by forward declarations
57 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
58 Include TR photon generation and adapt to new AliTRDhit
60 Revision 1.22 2000/06/27 13:08:50 cblume
61 Changed to Copy(TObject &A) to appease the HP-compiler
63 Revision 1.21 2000/06/09 11:10:07 cblume
64 Compiler warnings and coding conventions, next round
66 Revision 1.20 2000/06/08 18:32:58 cblume
67 Make code compliant to coding conventions
69 Revision 1.19 2000/06/07 16:27:32 cblume
70 Try to remove compiler warnings on Sun and HP
72 Revision 1.18 2000/05/08 16:17:27 cblume
75 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
76 Made inline function non-virtual. Bug fix in setting sensitive chamber
78 Revision 1.17 2000/02/28 19:10:26 cblume
79 Include the new TRD classes
81 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
82 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
84 Revision 1.16 1999/11/05 22:50:28 fca
85 Do not use Atan, removed from ROOT too
87 Revision 1.15 1999/11/02 17:20:19 fca
88 initialise nbytes before using it
90 Revision 1.14 1999/11/02 17:15:54 fca
91 Correct ansi scoping not accepted by HP compilers
93 Revision 1.13 1999/11/02 17:14:51 fca
94 Correct ansi scoping not accepted by HP compilers
96 Revision 1.12 1999/11/02 16:35:56 fca
97 New version of TRD introduced
99 Revision 1.11 1999/11/01 20:41:51 fca
100 Added protections against using the wrong version of FRAME
102 Revision 1.10 1999/09/29 09:24:35 fca
103 Introduction of the Copyright and cvs Log
107 ///////////////////////////////////////////////////////////////////////////////
109 // Transition Radiation Detector version 1 -- slow simulator //
113 <img src="picts/AliTRDfullClass.gif">
118 ///////////////////////////////////////////////////////////////////////////////
126 #include <TLorentzVector.h>
130 #include "AliConst.h"
132 #include "AliTRDv1.h"
133 #include "AliTRDhit.h"
134 #include "AliTRDmatrix.h"
135 #include "AliTRDgeometry.h"
136 #include "AliTRDsim.h"
140 //_____________________________________________________________________________
141 AliTRDv1::AliTRDv1():AliTRD()
144 // Default constructor
151 fSensSectorRange = 0;
158 //_____________________________________________________________________________
159 AliTRDv1::AliTRDv1(const char *name, const char *title)
163 // Standard constructor for Transition Radiation Detector version 1
170 fSensSectorRange = 0;
175 SetBufferSize(128000);
179 //_____________________________________________________________________________
180 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
186 ((AliTRDv1 &) trd).Copy(*this);
190 //_____________________________________________________________________________
191 AliTRDv1::~AliTRDv1()
194 // AliTRDv1 destructor
197 if (fDeltaE) delete fDeltaE;
202 //_____________________________________________________________________________
203 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
206 // Assignment operator
209 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
214 //_____________________________________________________________________________
215 void AliTRDv1::Copy(TObject &trd)
221 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
222 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
223 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
224 ((AliTRDv1 &) trd).fSensSector = fSensSector;
225 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
227 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
228 fTR->Copy(*((AliTRDv1 &) trd).fTR);
232 //_____________________________________________________________________________
233 void AliTRDv1::CreateGeometry()
236 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
237 // This version covers the full azimuth.
240 // Check that FRAME is there otherwise we have no place where to put the TRD
241 AliModule* frame = gAlice->GetModule("FRAME");
244 // Define the chambers
245 AliTRD::CreateGeometry();
249 //_____________________________________________________________________________
250 void AliTRDv1::CreateMaterials()
253 // Create materials for the Transition Radiation Detector version 1
256 AliTRD::CreateMaterials();
260 //_____________________________________________________________________________
261 void AliTRDv1::CreateTRhit(Int_t det)
264 // Creates an electron cluster from a TR photon.
265 // The photon is assumed to be created a the end of the radiator. The
266 // distance after which it deposits its energy takes into account the
267 // absorbtion of the entrance window and of the gas mixture in drift
272 const Int_t kPdgElectron = 11;
275 const Float_t kWion = 22.04;
277 // Maximum number of TR photons per track
278 const Int_t kNTR = 50;
280 TLorentzVector mom, pos;
282 // Create TR at the entrance of the chamber
283 if (gMC->IsTrackEntering()) {
285 // Create TR only for electrons
286 Int_t iPdg = gMC->TrackPid();
287 if (TMath::Abs(iPdg) != kPdgElectron) return;
293 gMC->TrackMomentum(mom);
294 Float_t pTot = mom.Rho();
295 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
297 printf("AliTRDv1::CreateTRhit -- ");
298 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
302 // Loop through the TR photons
303 for (Int_t iTR = 0; iTR < nTR; iTR++) {
305 Float_t energyMeV = eTR[iTR] * 0.001;
306 Float_t energyeV = eTR[iTR] * 1000.0;
307 Float_t absLength = 0;
310 // Take the absorbtion in the entrance window into account
311 Double_t muMy = fTR->GetMuMy(energyMeV);
312 sigma = muMy * fFoilDensity;
313 absLength = gRandom->Exp(sigma);
314 if (absLength < AliTRDgeometry::MyThick()) continue;
316 // The absorbtion cross sections in the drift gas
318 // Gas-mixture (Xe/CO2)
319 Double_t muXe = fTR->GetMuXe(energyMeV);
320 Double_t muCO = fTR->GetMuCO(energyMeV);
321 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
324 // Gas-mixture (Xe/Isobutane)
325 Double_t muXe = fTR->GetMuXe(energyMeV);
326 Double_t muBu = fTR->GetMuBu(energyMeV);
327 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
330 // The distance after which the energy of the TR photon
332 absLength = gRandom->Exp(sigma);
333 if (absLength > AliTRDgeometry::DrThick()) continue;
335 // The position of the absorbtion
337 gMC->TrackPosition(pos);
338 posHit[0] = pos[0] + mom[0] / pTot * absLength;
339 posHit[1] = pos[1] + mom[1] / pTot * absLength;
340 posHit[2] = pos[2] + mom[2] / pTot * absLength;
343 Int_t q = ((Int_t) (energyeV / kWion));
345 // Add the hit to the array. TR photon hits are marked
346 // by negative charge
347 AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
355 //_____________________________________________________________________________
356 void AliTRDv1::Init()
359 // Initialise Transition Radiation Detector after geometry has been built.
364 if(fDebug) printf("%s: Slow simulator\n",ClassName());
367 printf(" Only plane %d is sensitive\n",fSensPlane);
368 if (fSensChamber >= 0)
369 printf(" Only chamber %d is sensitive\n",fSensChamber);
370 if (fSensSector >= 0) {
371 Int_t sens1 = fSensSector;
372 Int_t sens2 = fSensSector + fSensSectorRange;
373 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
374 * AliTRDgeometry::Nsect();
375 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
379 printf("%s: TR simulation on\n",ClassName());
381 printf("%s: TR simulation off\n",ClassName());
384 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
385 const Float_t kPoti = 12.1;
386 // Maximum energy (50 keV);
387 const Float_t kEend = 50000.0;
388 // Ermilova distribution for the delta-ray spectrum
389 Float_t poti = TMath::Log(kPoti);
390 Float_t eEnd = TMath::Log(kEend);
391 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
394 printf("%s: ",ClassName());
395 for (Int_t i = 0; i < 80; i++) printf("*");
401 //_____________________________________________________________________________
402 AliTRDsim *AliTRDv1::CreateTR()
405 // Enables the simulation of TR
408 fTR = new AliTRDsim();
413 //_____________________________________________________________________________
414 void AliTRDv1::SetSensPlane(Int_t iplane)
417 // Defines the hit-sensitive plane (0-5)
420 if ((iplane < 0) || (iplane > 5)) {
421 printf("Wrong input value: %d\n",iplane);
422 printf("Use standard setting\n");
433 //_____________________________________________________________________________
434 void AliTRDv1::SetSensChamber(Int_t ichamber)
437 // Defines the hit-sensitive chamber (0-4)
440 if ((ichamber < 0) || (ichamber > 4)) {
441 printf("Wrong input value: %d\n",ichamber);
442 printf("Use standard setting\n");
449 fSensChamber = ichamber;
453 //_____________________________________________________________________________
454 void AliTRDv1::SetSensSector(Int_t isector)
457 // Defines the hit-sensitive sector (0-17)
460 SetSensSector(isector,1);
464 //_____________________________________________________________________________
465 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
468 // Defines a range of hit-sensitive sectors. The range is defined by
469 // <isector> (0-17) as the starting point and <nsector> as the number
470 // of sectors to be included.
473 if ((isector < 0) || (isector > 17)) {
474 printf("Wrong input value <isector>: %d\n",isector);
475 printf("Use standard setting\n");
477 fSensSectorRange = 0;
482 if ((nsector < 1) || (nsector > 18)) {
483 printf("Wrong input value <nsector>: %d\n",nsector);
484 printf("Use standard setting\n");
486 fSensSectorRange = 0;
492 fSensSector = isector;
493 fSensSectorRange = nsector;
497 //_____________________________________________________________________________
498 void AliTRDv1::StepManager()
501 // Slow simulator. Every charged track produces electron cluster as hits
502 // along its path across the drift volume. The step size is set acording
503 // to Bethe-Bloch. The energy distribution of the delta electrons follows
504 // a spectrum taken from Ermilova et al.
522 Double_t betaGamma, pp;
525 Bool_t drRegion = kFALSE;
526 Bool_t amRegion = kFALSE;
529 TString cIdSensDr = "J";
530 TString cIdSensAm = "K";
531 Char_t cIdChamber[3];
534 TLorentzVector pos, mom;
536 const Int_t kNplan = AliTRDgeometry::Nplan();
537 const Double_t kBig = 1.0E+12;
540 const Float_t kWion = 22.04;
541 // Maximum momentum for e+ e- g
542 const Float_t kPTotMaxEl = 0.002;
543 // Minimum energy for the step size adjustment
544 const Float_t kEkinMinStep = 1.0e-5;
545 // Plateau value of the energy-loss for electron in xenon
546 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
547 //const Double_t kPlateau = 1.70;
548 // the averaged value (26/3/99)
549 const Float_t kPlateau = 1.55;
550 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
551 const Float_t kPrim = 48.0;
552 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
553 const Float_t kPoti = 12.1;
556 const Int_t kPdgElectron = 11;
558 // Set the maximum step size to a very large number for all
559 // neutral particles and those outside the driftvolume
560 gMC->SetMaxStep(kBig);
562 // Use only charged tracks
563 if (( gMC->TrackCharge() ) &&
564 (!gMC->IsTrackStop() ) &&
565 (!gMC->IsTrackDisappeared())) {
567 // Inside a sensitive volume?
570 cIdCurrent = gMC->CurrentVolName();
571 if (cIdSensDr == cIdCurrent[1]) {
574 if (cIdSensAm == cIdCurrent[1]) {
577 if (drRegion || amRegion) {
579 // The hit coordinates and charge
580 gMC->TrackPosition(pos);
585 // The sector number (0 - 17)
586 // The numbering goes clockwise and starts at y = 0
587 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
592 sec = ((Int_t) (phi / 20));
594 // The plane and chamber number
595 cIdChamber[0] = cIdCurrent[2];
596 cIdChamber[1] = cIdCurrent[3];
597 Int_t idChamber = atoi(cIdChamber);
598 cha = ((Int_t) idChamber / kNplan);
599 pla = ((Int_t) idChamber % kNplan);
601 // Check on selected volumes
602 Int_t addthishit = 1;
604 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
605 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
606 if (fSensSector >= 0) {
607 Int_t sens1 = fSensSector;
608 Int_t sens2 = fSensSector + fSensSectorRange;
609 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
610 * AliTRDgeometry::Nsect();
612 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
615 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
623 // The detector number
624 det = fGeometry->GetDetector(pla,cha,sec);
626 // Special hits and TR photons only in the drift region
629 // Create some special hits with amplitude 0 at the entrance and
630 // exit of each chamber that contain the momentum components of the particle
631 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
632 gMC->TrackMomentum(mom);
636 AddHit(gAlice->CurrentTrack(),det,moms,0,kTRUE);
637 AddHit(gAlice->CurrentTrack(),det,hits,0,kTRUE);
640 // Create the hits from TR photons
641 if (fTR) CreateTRhit(det);
645 // Calculate the energy of the delta-electrons
646 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
647 eDelta = TMath::Max(eDelta,0.0);
649 // The number of secondary electrons created
650 qTot = ((Int_t) (eDelta / kWion) + 1);
652 // Create a new dEdx hit
654 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
657 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
660 // Calculate the maximum step size for the next tracking step
661 // Produce only one hit if Ekin is below cutoff
662 aMass = gMC->TrackMass();
663 if ((gMC->Etot() - aMass) > kEkinMinStep) {
665 // The energy loss according to Bethe Bloch
666 iPdg = TMath::Abs(gMC->TrackPid());
667 if ( (iPdg != kPdgElectron) ||
668 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
669 gMC->TrackMomentum(mom);
671 betaGamma = pTot / aMass;
672 pp = kPrim * BetheBloch(betaGamma);
673 // Take charge > 1 into account
674 charge = gMC->TrackCharge();
675 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
677 // Electrons above 20 Mev/c are at the plateau
679 pp = kPrim * kPlateau;
685 while ((random[0] == 1.) || (random[0] == 0.));
686 stepSize = - TMath::Log(random[0]) / pp;
687 gMC->SetMaxStep(stepSize);
700 //_____________________________________________________________________________
701 Double_t AliTRDv1::BetheBloch(Double_t bg)
704 // Parametrization of the Bethe-Bloch-curve
705 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
708 // This parameters have been adjusted to averaged values from GEANT
709 const Double_t kP1 = 7.17960e-02;
710 const Double_t kP2 = 8.54196;
711 const Double_t kP3 = 1.38065e-06;
712 const Double_t kP4 = 5.30972;
713 const Double_t kP5 = 2.83798;
715 // This parameters have been adjusted to Xe-data found in:
716 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
717 //const Double_t kP1 = 0.76176E-1;
718 //const Double_t kP2 = 10.632;
719 //const Double_t kP3 = 3.17983E-6;
720 //const Double_t kP4 = 1.8631;
721 //const Double_t kP5 = 1.9479;
723 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
724 const Double_t kBgMin = 0.8;
725 const Double_t kBBMax = 6.83298;
726 //const Double_t kBgMin = 0.6;
727 //const Double_t kBBMax = 17.2809;
728 //const Double_t kBgMin = 0.4;
729 //const Double_t kBBMax = 82.0;
732 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
733 Double_t aa = TMath::Power(yy,kP4);
734 Double_t bb = TMath::Power((1./bg),kP5);
735 bb = TMath::Log(kP3 + bb);
736 return ((kP2 - aa - bb)*kP1 / aa);
744 //_____________________________________________________________________________
745 Double_t Ermilova(Double_t *x, Double_t *)
748 // Calculates the delta-ray energy distribution according to Ermilova.
749 // Logarithmic scale !
758 const Int_t kNv = 31;
760 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
761 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
762 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
763 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
764 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
765 , 9.4727, 9.9035,10.3735,10.5966,10.8198
768 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
769 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
770 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
771 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
772 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
773 , 0.04 , 0.023, 0.015, 0.011, 0.01
782 dpos = energy - vxe[pos2++];
786 if (pos2 > kNv) pos2 = kNv - 1;
789 // Differentiate between the sampling points
790 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);