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 1.33.6.2 2002/07/24 10:09:31 alibrary
21 Revision 1.34 2002/06/13 08:11:56 cblume
22 Add the track references
24 Revision 1.33 2002/02/20 14:01:40 hristov
25 Compare a TString with a string, otherwise the conversion cannot be done on Sun
27 Revision 1.32 2002/02/13 16:58:37 cblume
28 Bug fix reported by Jiri. Make atoi input zero terminated in StepManager()
30 Revision 1.31 2002/02/11 14:25:27 cblume
31 Geometry update, compressed hit structure
33 Revision 1.30 2001/05/21 16:45:47 hristov
34 Last minute changes (C.Blume)
36 Revision 1.29 2001/05/16 14:57:28 alibrary
37 New files for folders and Stack
39 Revision 1.28 2001/05/07 08:03:22 cblume
40 Generate also hits in the amplification region
42 Revision 1.27 2001/03/30 14:40:15 cblume
43 Update of the digitization parameter
45 Revision 1.26 2000/11/30 17:38:08 cblume
46 Changes to get in line with new STEER and EVGEN
48 Revision 1.25 2000/11/15 14:30:16 cblume
49 Fixed bug in calculating detector no. of extra hit
51 Revision 1.24 2000/11/10 14:58:36 cblume
52 Introduce additional hit with amplitude 0 at the chamber borders
54 Revision 1.23 2000/11/01 14:53:21 cblume
55 Merge with TRD-develop
57 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
60 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
63 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
64 Replace include files by forward declarations
66 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
67 Include TR photon generation and adapt to new AliTRDhit
69 Revision 1.22 2000/06/27 13:08:50 cblume
70 Changed to Copy(TObject &A) to appease the HP-compiler
72 Revision 1.21 2000/06/09 11:10:07 cblume
73 Compiler warnings and coding conventions, next round
75 Revision 1.20 2000/06/08 18:32:58 cblume
76 Make code compliant to coding conventions
78 Revision 1.19 2000/06/07 16:27:32 cblume
79 Try to remove compiler warnings on Sun and HP
81 Revision 1.18 2000/05/08 16:17:27 cblume
84 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
85 Made inline function non-virtual. Bug fix in setting sensitive chamber
87 Revision 1.17 2000/02/28 19:10:26 cblume
88 Include the new TRD classes
90 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
91 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
93 Revision 1.16 1999/11/05 22:50:28 fca
94 Do not use Atan, removed from ROOT too
96 Revision 1.15 1999/11/02 17:20:19 fca
97 initialise nbytes before using it
99 Revision 1.14 1999/11/02 17:15:54 fca
100 Correct ansi scoping not accepted by HP compilers
102 Revision 1.13 1999/11/02 17:14:51 fca
103 Correct ansi scoping not accepted by HP compilers
105 Revision 1.12 1999/11/02 16:35:56 fca
106 New version of TRD introduced
108 Revision 1.11 1999/11/01 20:41:51 fca
109 Added protections against using the wrong version of FRAME
111 Revision 1.10 1999/09/29 09:24:35 fca
112 Introduction of the Copyright and cvs Log
116 ///////////////////////////////////////////////////////////////////////////////
118 // Transition Radiation Detector version 1 -- slow simulator //
122 <img src="picts/AliTRDfullClass.gif">
127 ///////////////////////////////////////////////////////////////////////////////
135 #include <TLorentzVector.h>
139 #include "AliConst.h"
141 #include "AliTRDv1.h"
142 #include "AliTRDhit.h"
143 #include "AliTRDmatrix.h"
144 #include "AliTRDgeometry.h"
145 #include "AliTRDsim.h"
149 //_____________________________________________________________________________
150 AliTRDv1::AliTRDv1():AliTRD()
153 // Default constructor
160 fSensSectorRange = 0;
167 //_____________________________________________________________________________
168 AliTRDv1::AliTRDv1(const char *name, const char *title)
172 // Standard constructor for Transition Radiation Detector version 1
179 fSensSectorRange = 0;
184 SetBufferSize(128000);
188 //_____________________________________________________________________________
189 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
195 ((AliTRDv1 &) trd).Copy(*this);
199 //_____________________________________________________________________________
200 AliTRDv1::~AliTRDv1()
203 // AliTRDv1 destructor
206 if (fDeltaE) delete fDeltaE;
211 //_____________________________________________________________________________
212 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
215 // Assignment operator
218 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
223 //_____________________________________________________________________________
224 void AliTRDv1::Copy(TObject &trd)
230 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
231 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
232 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
233 ((AliTRDv1 &) trd).fSensSector = fSensSector;
234 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
236 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
237 fTR->Copy(*((AliTRDv1 &) trd).fTR);
241 //_____________________________________________________________________________
242 void AliTRDv1::CreateGeometry()
245 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
246 // This version covers the full azimuth.
249 // Check that FRAME is there otherwise we have no place where to put the TRD
250 AliModule* frame = gAlice->GetModule("FRAME");
253 // Define the chambers
254 AliTRD::CreateGeometry();
258 //_____________________________________________________________________________
259 void AliTRDv1::CreateMaterials()
262 // Create materials for the Transition Radiation Detector version 1
265 AliTRD::CreateMaterials();
269 //_____________________________________________________________________________
270 void AliTRDv1::CreateTRhit(Int_t det)
273 // Creates an electron cluster from a TR photon.
274 // The photon is assumed to be created a the end of the radiator. The
275 // distance after which it deposits its energy takes into account the
276 // absorbtion of the entrance window and of the gas mixture in drift
281 const Int_t kPdgElectron = 11;
284 const Float_t kWion = 22.04;
286 // Maximum number of TR photons per track
287 const Int_t kNTR = 50;
289 TLorentzVector mom, pos;
291 // Create TR at the entrance of the chamber
292 if (gMC->IsTrackEntering()) {
294 // Create TR only for electrons
295 Int_t iPdg = gMC->TrackPid();
296 if (TMath::Abs(iPdg) != kPdgElectron) return;
302 gMC->TrackMomentum(mom);
303 Float_t pTot = mom.Rho();
304 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
306 printf("AliTRDv1::CreateTRhit -- ");
307 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
311 // Loop through the TR photons
312 for (Int_t iTR = 0; iTR < nTR; iTR++) {
314 Float_t energyMeV = eTR[iTR] * 0.001;
315 Float_t energyeV = eTR[iTR] * 1000.0;
316 Float_t absLength = 0;
319 // Take the absorbtion in the entrance window into account
320 Double_t muMy = fTR->GetMuMy(energyMeV);
321 sigma = muMy * fFoilDensity;
322 absLength = gRandom->Exp(sigma);
323 if (absLength < AliTRDgeometry::MyThick()) continue;
325 // The absorbtion cross sections in the drift gas
327 // Gas-mixture (Xe/CO2)
328 Double_t muXe = fTR->GetMuXe(energyMeV);
329 Double_t muCO = fTR->GetMuCO(energyMeV);
330 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
333 // Gas-mixture (Xe/Isobutane)
334 Double_t muXe = fTR->GetMuXe(energyMeV);
335 Double_t muBu = fTR->GetMuBu(energyMeV);
336 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
339 // The distance after which the energy of the TR photon
341 absLength = gRandom->Exp(sigma);
342 if (absLength > AliTRDgeometry::DrThick()) continue;
344 // The position of the absorbtion
346 gMC->TrackPosition(pos);
347 posHit[0] = pos[0] + mom[0] / pTot * absLength;
348 posHit[1] = pos[1] + mom[1] / pTot * absLength;
349 posHit[2] = pos[2] + mom[2] / pTot * absLength;
352 Int_t q = ((Int_t) (energyeV / kWion));
354 // Add the hit to the array. TR photon hits are marked
355 // by negative charge
356 AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
364 //_____________________________________________________________________________
365 void AliTRDv1::Init()
368 // Initialise Transition Radiation Detector after geometry has been built.
373 if(fDebug) printf("%s: Slow simulator\n",ClassName());
376 printf(" Only plane %d is sensitive\n",fSensPlane);
377 if (fSensChamber >= 0)
378 printf(" Only chamber %d is sensitive\n",fSensChamber);
379 if (fSensSector >= 0) {
380 Int_t sens1 = fSensSector;
381 Int_t sens2 = fSensSector + fSensSectorRange;
382 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
383 * AliTRDgeometry::Nsect();
384 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
388 printf("%s: TR simulation on\n",ClassName());
390 printf("%s: TR simulation off\n",ClassName());
393 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
394 const Float_t kPoti = 12.1;
395 // Maximum energy (50 keV);
396 const Float_t kEend = 50000.0;
397 // Ermilova distribution for the delta-ray spectrum
398 Float_t poti = TMath::Log(kPoti);
399 Float_t eEnd = TMath::Log(kEend);
400 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
403 printf("%s: ",ClassName());
404 for (Int_t i = 0; i < 80; i++) printf("*");
410 //_____________________________________________________________________________
411 AliTRDsim *AliTRDv1::CreateTR()
414 // Enables the simulation of TR
417 fTR = new AliTRDsim();
422 //_____________________________________________________________________________
423 void AliTRDv1::SetSensPlane(Int_t iplane)
426 // Defines the hit-sensitive plane (0-5)
429 if ((iplane < 0) || (iplane > 5)) {
430 printf("Wrong input value: %d\n",iplane);
431 printf("Use standard setting\n");
442 //_____________________________________________________________________________
443 void AliTRDv1::SetSensChamber(Int_t ichamber)
446 // Defines the hit-sensitive chamber (0-4)
449 if ((ichamber < 0) || (ichamber > 4)) {
450 printf("Wrong input value: %d\n",ichamber);
451 printf("Use standard setting\n");
458 fSensChamber = ichamber;
462 //_____________________________________________________________________________
463 void AliTRDv1::SetSensSector(Int_t isector)
466 // Defines the hit-sensitive sector (0-17)
469 SetSensSector(isector,1);
473 //_____________________________________________________________________________
474 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
477 // Defines a range of hit-sensitive sectors. The range is defined by
478 // <isector> (0-17) as the starting point and <nsector> as the number
479 // of sectors to be included.
482 if ((isector < 0) || (isector > 17)) {
483 printf("Wrong input value <isector>: %d\n",isector);
484 printf("Use standard setting\n");
486 fSensSectorRange = 0;
491 if ((nsector < 1) || (nsector > 18)) {
492 printf("Wrong input value <nsector>: %d\n",nsector);
493 printf("Use standard setting\n");
495 fSensSectorRange = 0;
501 fSensSector = isector;
502 fSensSectorRange = nsector;
506 //_____________________________________________________________________________
507 void AliTRDv1::StepManager()
510 // Slow simulator. Every charged track produces electron cluster as hits
511 // along its path across the drift volume. The step size is set acording
512 // to Bethe-Bloch. The energy distribution of the delta electrons follows
513 // a spectrum taken from Ermilova et al.
530 Double_t betaGamma, pp;
533 Bool_t drRegion = kFALSE;
534 Bool_t amRegion = kFALSE;
537 TString cIdSensDr = "J";
538 TString cIdSensAm = "K";
539 Char_t cIdChamber[3];
542 TLorentzVector pos, mom;
544 const Int_t kNplan = AliTRDgeometry::Nplan();
545 const Double_t kBig = 1.0E+12;
548 const Float_t kWion = 22.04;
549 // Maximum momentum for e+ e- g
550 const Float_t kPTotMaxEl = 0.002;
551 // Minimum energy for the step size adjustment
552 const Float_t kEkinMinStep = 1.0e-5;
553 // Plateau value of the energy-loss for electron in xenon
554 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
555 //const Double_t kPlateau = 1.70;
556 // the averaged value (26/3/99)
557 const Float_t kPlateau = 1.55;
558 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
559 const Float_t kPrim = 48.0;
560 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
561 const Float_t kPoti = 12.1;
564 const Int_t kPdgElectron = 11;
566 // Set the maximum step size to a very large number for all
567 // neutral particles and those outside the driftvolume
568 gMC->SetMaxStep(kBig);
570 // Use only charged tracks
571 if (( gMC->TrackCharge() ) &&
572 (!gMC->IsTrackStop() ) &&
573 (!gMC->IsTrackDisappeared())) {
575 // Inside a sensitive volume?
578 cIdCurrent = gMC->CurrentVolName();
579 if (cIdSensDr == cIdCurrent[1]) {
582 if (cIdSensAm == cIdCurrent[1]) {
585 if (drRegion || amRegion) {
587 // The hit coordinates and charge
588 gMC->TrackPosition(pos);
593 // The sector number (0 - 17)
594 // The numbering goes clockwise and starts at y = 0
595 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
600 sec = ((Int_t) (phi / 20));
602 // The plane and chamber number
603 cIdChamber[0] = cIdCurrent[2];
604 cIdChamber[1] = cIdCurrent[3];
605 Int_t idChamber = atoi(cIdChamber);
606 cha = ((Int_t) idChamber / kNplan);
607 pla = ((Int_t) idChamber % kNplan);
609 // Check on selected volumes
610 Int_t addthishit = 1;
612 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
613 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
614 if (fSensSector >= 0) {
615 Int_t sens1 = fSensSector;
616 Int_t sens2 = fSensSector + fSensSectorRange;
617 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
618 * AliTRDgeometry::Nsect();
620 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
623 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
631 // The detector number
632 det = fGeometry->GetDetector(pla,cha,sec);
634 // Special hits and TR photons only in the drift region
637 // Create a track reference at the entrance and
638 // exit of each chamber that contain the
639 // momentum components of the particle
640 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
641 gMC->TrackMomentum(mom);
642 AddTrackReference(gAlice->CurrentTrack(),mom,pos);
645 // Create the hits from TR photons
646 if (fTR) CreateTRhit(det);
650 // Calculate the energy of the delta-electrons
651 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
652 eDelta = TMath::Max(eDelta,0.0);
654 // The number of secondary electrons created
655 qTot = ((Int_t) (eDelta / kWion) + 1);
657 // Create a new dEdx hit
659 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
662 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
665 // Calculate the maximum step size for the next tracking step
666 // Produce only one hit if Ekin is below cutoff
667 aMass = gMC->TrackMass();
668 if ((gMC->Etot() - aMass) > kEkinMinStep) {
670 // The energy loss according to Bethe Bloch
671 iPdg = TMath::Abs(gMC->TrackPid());
672 if ( (iPdg != kPdgElectron) ||
673 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
674 gMC->TrackMomentum(mom);
676 betaGamma = pTot / aMass;
677 pp = kPrim * BetheBloch(betaGamma);
678 // Take charge > 1 into account
679 charge = gMC->TrackCharge();
680 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
682 // Electrons above 20 Mev/c are at the plateau
684 pp = kPrim * kPlateau;
689 gMC->GetRandom()->RndmArray(1, random);
690 while ((random[0] == 1.) || (random[0] == 0.));
691 stepSize = - TMath::Log(random[0]) / pp;
692 gMC->SetMaxStep(stepSize);
705 //_____________________________________________________________________________
706 Double_t AliTRDv1::BetheBloch(Double_t bg)
709 // Parametrization of the Bethe-Bloch-curve
710 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
713 // This parameters have been adjusted to averaged values from GEANT
714 const Double_t kP1 = 7.17960e-02;
715 const Double_t kP2 = 8.54196;
716 const Double_t kP3 = 1.38065e-06;
717 const Double_t kP4 = 5.30972;
718 const Double_t kP5 = 2.83798;
720 // This parameters have been adjusted to Xe-data found in:
721 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
722 //const Double_t kP1 = 0.76176E-1;
723 //const Double_t kP2 = 10.632;
724 //const Double_t kP3 = 3.17983E-6;
725 //const Double_t kP4 = 1.8631;
726 //const Double_t kP5 = 1.9479;
728 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
729 const Double_t kBgMin = 0.8;
730 const Double_t kBBMax = 6.83298;
731 //const Double_t kBgMin = 0.6;
732 //const Double_t kBBMax = 17.2809;
733 //const Double_t kBgMin = 0.4;
734 //const Double_t kBBMax = 82.0;
737 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
738 Double_t aa = TMath::Power(yy,kP4);
739 Double_t bb = TMath::Power((1./bg),kP5);
740 bb = TMath::Log(kP3 + bb);
741 return ((kP2 - aa - bb)*kP1 / aa);
749 //_____________________________________________________________________________
750 Double_t Ermilova(Double_t *x, Double_t *)
753 // Calculates the delta-ray energy distribution according to Ermilova.
754 // Logarithmic scale !
763 const Int_t kNv = 31;
765 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
766 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
767 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
768 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
769 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
770 , 9.4727, 9.9035,10.3735,10.5966,10.8198
773 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
774 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
775 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
776 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
777 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
778 , 0.04 , 0.023, 0.015, 0.011, 0.01
787 dpos = energy - vxe[pos2++];
791 if (pos2 > kNv) pos2 = kNv - 1;
794 // Differentiate between the sampling points
795 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);