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 2002/02/20 14:01:40 hristov
19 Compare a TString with a string, otherwise the conversion cannot be done on Sun
21 Revision 1.32 2002/02/13 16:58:37 cblume
22 Bug fix reported by Jiri. Make atoi input zero terminated in StepManager()
24 Revision 1.31 2002/02/11 14:25:27 cblume
25 Geometry update, compressed hit structure
27 Revision 1.30 2001/05/21 16:45:47 hristov
28 Last minute changes (C.Blume)
30 Revision 1.29 2001/05/16 14:57:28 alibrary
31 New files for folders and Stack
33 Revision 1.28 2001/05/07 08:03:22 cblume
34 Generate also hits in the amplification region
36 Revision 1.27 2001/03/30 14:40:15 cblume
37 Update of the digitization parameter
39 Revision 1.26 2000/11/30 17:38:08 cblume
40 Changes to get in line with new STEER and EVGEN
42 Revision 1.25 2000/11/15 14:30:16 cblume
43 Fixed bug in calculating detector no. of extra hit
45 Revision 1.24 2000/11/10 14:58:36 cblume
46 Introduce additional hit with amplitude 0 at the chamber borders
48 Revision 1.23 2000/11/01 14:53:21 cblume
49 Merge with TRD-develop
51 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
54 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
57 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
58 Replace include files by forward declarations
60 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
61 Include TR photon generation and adapt to new AliTRDhit
63 Revision 1.22 2000/06/27 13:08:50 cblume
64 Changed to Copy(TObject &A) to appease the HP-compiler
66 Revision 1.21 2000/06/09 11:10:07 cblume
67 Compiler warnings and coding conventions, next round
69 Revision 1.20 2000/06/08 18:32:58 cblume
70 Make code compliant to coding conventions
72 Revision 1.19 2000/06/07 16:27:32 cblume
73 Try to remove compiler warnings on Sun and HP
75 Revision 1.18 2000/05/08 16:17:27 cblume
78 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
79 Made inline function non-virtual. Bug fix in setting sensitive chamber
81 Revision 1.17 2000/02/28 19:10:26 cblume
82 Include the new TRD classes
84 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
85 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
87 Revision 1.16 1999/11/05 22:50:28 fca
88 Do not use Atan, removed from ROOT too
90 Revision 1.15 1999/11/02 17:20:19 fca
91 initialise nbytes before using it
93 Revision 1.14 1999/11/02 17:15:54 fca
94 Correct ansi scoping not accepted by HP compilers
96 Revision 1.13 1999/11/02 17:14:51 fca
97 Correct ansi scoping not accepted by HP compilers
99 Revision 1.12 1999/11/02 16:35:56 fca
100 New version of TRD introduced
102 Revision 1.11 1999/11/01 20:41:51 fca
103 Added protections against using the wrong version of FRAME
105 Revision 1.10 1999/09/29 09:24:35 fca
106 Introduction of the Copyright and cvs Log
110 ///////////////////////////////////////////////////////////////////////////////
112 // Transition Radiation Detector version 1 -- slow simulator //
116 <img src="picts/AliTRDfullClass.gif">
121 ///////////////////////////////////////////////////////////////////////////////
129 #include <TLorentzVector.h>
133 #include "AliConst.h"
135 #include "AliTRDv1.h"
136 #include "AliTRDhit.h"
137 #include "AliTRDmatrix.h"
138 #include "AliTRDgeometry.h"
139 #include "AliTRDsim.h"
143 //_____________________________________________________________________________
144 AliTRDv1::AliTRDv1():AliTRD()
147 // Default constructor
154 fSensSectorRange = 0;
161 //_____________________________________________________________________________
162 AliTRDv1::AliTRDv1(const char *name, const char *title)
166 // Standard constructor for Transition Radiation Detector version 1
173 fSensSectorRange = 0;
178 SetBufferSize(128000);
182 //_____________________________________________________________________________
183 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
189 ((AliTRDv1 &) trd).Copy(*this);
193 //_____________________________________________________________________________
194 AliTRDv1::~AliTRDv1()
197 // AliTRDv1 destructor
200 if (fDeltaE) delete fDeltaE;
205 //_____________________________________________________________________________
206 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
209 // Assignment operator
212 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
217 //_____________________________________________________________________________
218 void AliTRDv1::Copy(TObject &trd)
224 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
225 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
226 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
227 ((AliTRDv1 &) trd).fSensSector = fSensSector;
228 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
230 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
231 fTR->Copy(*((AliTRDv1 &) trd).fTR);
235 //_____________________________________________________________________________
236 void AliTRDv1::CreateGeometry()
239 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
240 // This version covers the full azimuth.
243 // Check that FRAME is there otherwise we have no place where to put the TRD
244 AliModule* frame = gAlice->GetModule("FRAME");
247 // Define the chambers
248 AliTRD::CreateGeometry();
252 //_____________________________________________________________________________
253 void AliTRDv1::CreateMaterials()
256 // Create materials for the Transition Radiation Detector version 1
259 AliTRD::CreateMaterials();
263 //_____________________________________________________________________________
264 void AliTRDv1::CreateTRhit(Int_t det)
267 // Creates an electron cluster from a TR photon.
268 // The photon is assumed to be created a the end of the radiator. The
269 // distance after which it deposits its energy takes into account the
270 // absorbtion of the entrance window and of the gas mixture in drift
275 const Int_t kPdgElectron = 11;
278 const Float_t kWion = 22.04;
280 // Maximum number of TR photons per track
281 const Int_t kNTR = 50;
283 TLorentzVector mom, pos;
285 // Create TR at the entrance of the chamber
286 if (gMC->IsTrackEntering()) {
288 // Create TR only for electrons
289 Int_t iPdg = gMC->TrackPid();
290 if (TMath::Abs(iPdg) != kPdgElectron) return;
296 gMC->TrackMomentum(mom);
297 Float_t pTot = mom.Rho();
298 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
300 printf("AliTRDv1::CreateTRhit -- ");
301 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
305 // Loop through the TR photons
306 for (Int_t iTR = 0; iTR < nTR; iTR++) {
308 Float_t energyMeV = eTR[iTR] * 0.001;
309 Float_t energyeV = eTR[iTR] * 1000.0;
310 Float_t absLength = 0;
313 // Take the absorbtion in the entrance window into account
314 Double_t muMy = fTR->GetMuMy(energyMeV);
315 sigma = muMy * fFoilDensity;
316 absLength = gRandom->Exp(sigma);
317 if (absLength < AliTRDgeometry::MyThick()) continue;
319 // The absorbtion cross sections in the drift gas
321 // Gas-mixture (Xe/CO2)
322 Double_t muXe = fTR->GetMuXe(energyMeV);
323 Double_t muCO = fTR->GetMuCO(energyMeV);
324 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
327 // Gas-mixture (Xe/Isobutane)
328 Double_t muXe = fTR->GetMuXe(energyMeV);
329 Double_t muBu = fTR->GetMuBu(energyMeV);
330 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
333 // The distance after which the energy of the TR photon
335 absLength = gRandom->Exp(sigma);
336 if (absLength > AliTRDgeometry::DrThick()) continue;
338 // The position of the absorbtion
340 gMC->TrackPosition(pos);
341 posHit[0] = pos[0] + mom[0] / pTot * absLength;
342 posHit[1] = pos[1] + mom[1] / pTot * absLength;
343 posHit[2] = pos[2] + mom[2] / pTot * absLength;
346 Int_t q = ((Int_t) (energyeV / kWion));
348 // Add the hit to the array. TR photon hits are marked
349 // by negative charge
350 AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
358 //_____________________________________________________________________________
359 void AliTRDv1::Init()
362 // Initialise Transition Radiation Detector after geometry has been built.
367 if(fDebug) printf("%s: Slow simulator\n",ClassName());
370 printf(" Only plane %d is sensitive\n",fSensPlane);
371 if (fSensChamber >= 0)
372 printf(" Only chamber %d is sensitive\n",fSensChamber);
373 if (fSensSector >= 0) {
374 Int_t sens1 = fSensSector;
375 Int_t sens2 = fSensSector + fSensSectorRange;
376 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
377 * AliTRDgeometry::Nsect();
378 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
382 printf("%s: TR simulation on\n",ClassName());
384 printf("%s: TR simulation off\n",ClassName());
387 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
388 const Float_t kPoti = 12.1;
389 // Maximum energy (50 keV);
390 const Float_t kEend = 50000.0;
391 // Ermilova distribution for the delta-ray spectrum
392 Float_t poti = TMath::Log(kPoti);
393 Float_t eEnd = TMath::Log(kEend);
394 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
397 printf("%s: ",ClassName());
398 for (Int_t i = 0; i < 80; i++) printf("*");
404 //_____________________________________________________________________________
405 AliTRDsim *AliTRDv1::CreateTR()
408 // Enables the simulation of TR
411 fTR = new AliTRDsim();
416 //_____________________________________________________________________________
417 void AliTRDv1::SetSensPlane(Int_t iplane)
420 // Defines the hit-sensitive plane (0-5)
423 if ((iplane < 0) || (iplane > 5)) {
424 printf("Wrong input value: %d\n",iplane);
425 printf("Use standard setting\n");
436 //_____________________________________________________________________________
437 void AliTRDv1::SetSensChamber(Int_t ichamber)
440 // Defines the hit-sensitive chamber (0-4)
443 if ((ichamber < 0) || (ichamber > 4)) {
444 printf("Wrong input value: %d\n",ichamber);
445 printf("Use standard setting\n");
452 fSensChamber = ichamber;
456 //_____________________________________________________________________________
457 void AliTRDv1::SetSensSector(Int_t isector)
460 // Defines the hit-sensitive sector (0-17)
463 SetSensSector(isector,1);
467 //_____________________________________________________________________________
468 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
471 // Defines a range of hit-sensitive sectors. The range is defined by
472 // <isector> (0-17) as the starting point and <nsector> as the number
473 // of sectors to be included.
476 if ((isector < 0) || (isector > 17)) {
477 printf("Wrong input value <isector>: %d\n",isector);
478 printf("Use standard setting\n");
480 fSensSectorRange = 0;
485 if ((nsector < 1) || (nsector > 18)) {
486 printf("Wrong input value <nsector>: %d\n",nsector);
487 printf("Use standard setting\n");
489 fSensSectorRange = 0;
495 fSensSector = isector;
496 fSensSectorRange = nsector;
500 //_____________________________________________________________________________
501 void AliTRDv1::StepManager()
504 // Slow simulator. Every charged track produces electron cluster as hits
505 // along its path across the drift volume. The step size is set acording
506 // to Bethe-Bloch. The energy distribution of the delta electrons follows
507 // a spectrum taken from Ermilova et al.
524 Double_t betaGamma, pp;
527 Bool_t drRegion = kFALSE;
528 Bool_t amRegion = kFALSE;
531 TString cIdSensDr = "J";
532 TString cIdSensAm = "K";
533 Char_t cIdChamber[3];
536 TLorentzVector pos, mom;
538 const Int_t kNplan = AliTRDgeometry::Nplan();
539 const Double_t kBig = 1.0E+12;
542 const Float_t kWion = 22.04;
543 // Maximum momentum for e+ e- g
544 const Float_t kPTotMaxEl = 0.002;
545 // Minimum energy for the step size adjustment
546 const Float_t kEkinMinStep = 1.0e-5;
547 // Plateau value of the energy-loss for electron in xenon
548 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
549 //const Double_t kPlateau = 1.70;
550 // the averaged value (26/3/99)
551 const Float_t kPlateau = 1.55;
552 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
553 const Float_t kPrim = 48.0;
554 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
555 const Float_t kPoti = 12.1;
558 const Int_t kPdgElectron = 11;
560 // Set the maximum step size to a very large number for all
561 // neutral particles and those outside the driftvolume
562 gMC->SetMaxStep(kBig);
564 // Use only charged tracks
565 if (( gMC->TrackCharge() ) &&
566 (!gMC->IsTrackStop() ) &&
567 (!gMC->IsTrackDisappeared())) {
569 // Inside a sensitive volume?
572 cIdCurrent = gMC->CurrentVolName();
573 if (cIdSensDr == cIdCurrent[1]) {
576 if (cIdSensAm == cIdCurrent[1]) {
579 if (drRegion || amRegion) {
581 // The hit coordinates and charge
582 gMC->TrackPosition(pos);
587 // The sector number (0 - 17)
588 // The numbering goes clockwise and starts at y = 0
589 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
594 sec = ((Int_t) (phi / 20));
596 // The plane and chamber number
597 cIdChamber[0] = cIdCurrent[2];
598 cIdChamber[1] = cIdCurrent[3];
599 Int_t idChamber = atoi(cIdChamber);
600 cha = ((Int_t) idChamber / kNplan);
601 pla = ((Int_t) idChamber % kNplan);
603 // Check on selected volumes
604 Int_t addthishit = 1;
606 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
607 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
608 if (fSensSector >= 0) {
609 Int_t sens1 = fSensSector;
610 Int_t sens2 = fSensSector + fSensSectorRange;
611 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
612 * AliTRDgeometry::Nsect();
614 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
617 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
625 // The detector number
626 det = fGeometry->GetDetector(pla,cha,sec);
628 // Special hits and TR photons only in the drift region
631 // Create a track reference at the entrance and
632 // exit of each chamber that contain the
633 // momentum components of the particle
634 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
635 gMC->TrackMomentum(mom);
636 AddTrackReference(gAlice->CurrentTrack(),mom,pos);
639 // Create the hits from TR photons
640 if (fTR) CreateTRhit(det);
644 // Calculate the energy of the delta-electrons
645 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
646 eDelta = TMath::Max(eDelta,0.0);
648 // The number of secondary electrons created
649 qTot = ((Int_t) (eDelta / kWion) + 1);
651 // Create a new dEdx hit
653 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
656 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
659 // Calculate the maximum step size for the next tracking step
660 // Produce only one hit if Ekin is below cutoff
661 aMass = gMC->TrackMass();
662 if ((gMC->Etot() - aMass) > kEkinMinStep) {
664 // The energy loss according to Bethe Bloch
665 iPdg = TMath::Abs(gMC->TrackPid());
666 if ( (iPdg != kPdgElectron) ||
667 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
668 gMC->TrackMomentum(mom);
670 betaGamma = pTot / aMass;
671 pp = kPrim * BetheBloch(betaGamma);
672 // Take charge > 1 into account
673 charge = gMC->TrackCharge();
674 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
676 // Electrons above 20 Mev/c are at the plateau
678 pp = kPrim * kPlateau;
684 while ((random[0] == 1.) || (random[0] == 0.));
685 stepSize = - TMath::Log(random[0]) / pp;
686 gMC->SetMaxStep(stepSize);
699 //_____________________________________________________________________________
700 Double_t AliTRDv1::BetheBloch(Double_t bg)
703 // Parametrization of the Bethe-Bloch-curve
704 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
707 // This parameters have been adjusted to averaged values from GEANT
708 const Double_t kP1 = 7.17960e-02;
709 const Double_t kP2 = 8.54196;
710 const Double_t kP3 = 1.38065e-06;
711 const Double_t kP4 = 5.30972;
712 const Double_t kP5 = 2.83798;
714 // This parameters have been adjusted to Xe-data found in:
715 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
716 //const Double_t kP1 = 0.76176E-1;
717 //const Double_t kP2 = 10.632;
718 //const Double_t kP3 = 3.17983E-6;
719 //const Double_t kP4 = 1.8631;
720 //const Double_t kP5 = 1.9479;
722 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
723 const Double_t kBgMin = 0.8;
724 const Double_t kBBMax = 6.83298;
725 //const Double_t kBgMin = 0.6;
726 //const Double_t kBBMax = 17.2809;
727 //const Double_t kBgMin = 0.4;
728 //const Double_t kBBMax = 82.0;
731 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
732 Double_t aa = TMath::Power(yy,kP4);
733 Double_t bb = TMath::Power((1./bg),kP5);
734 bb = TMath::Log(kP3 + bb);
735 return ((kP2 - aa - bb)*kP1 / aa);
743 //_____________________________________________________________________________
744 Double_t Ermilova(Double_t *x, Double_t *)
747 // Calculates the delta-ray energy distribution according to Ermilova.
748 // Logarithmic scale !
757 const Int_t kNv = 31;
759 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
760 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
761 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
762 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
763 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
764 , 9.4727, 9.9035,10.3735,10.5966,10.8198
767 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
768 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
769 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
770 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
771 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
772 , 0.04 , 0.023, 0.015, 0.011, 0.01
781 dpos = energy - vxe[pos2++];
785 if (pos2 > kNv) pos2 = kNv - 1;
788 // Differentiate between the sampling points
789 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);