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 1.25 2000/11/15 14:30:16 cblume
19 Fixed bug in calculating detector no. of extra hit
21 Revision 1.24 2000/11/10 14:58:36 cblume
22 Introduce additional hit with amplitude 0 at the chamber borders
24 Revision 1.23 2000/11/01 14:53:21 cblume
25 Merge with TRD-develop
27 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
30 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
33 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
34 Replace include files by forward declarations
36 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
37 Include TR photon generation and adapt to new AliTRDhit
39 Revision 1.22 2000/06/27 13:08:50 cblume
40 Changed to Copy(TObject &A) to appease the HP-compiler
42 Revision 1.21 2000/06/09 11:10:07 cblume
43 Compiler warnings and coding conventions, next round
45 Revision 1.20 2000/06/08 18:32:58 cblume
46 Make code compliant to coding conventions
48 Revision 1.19 2000/06/07 16:27:32 cblume
49 Try to remove compiler warnings on Sun and HP
51 Revision 1.18 2000/05/08 16:17:27 cblume
54 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
55 Made inline function non-virtual. Bug fix in setting sensitive chamber
57 Revision 1.17 2000/02/28 19:10:26 cblume
58 Include the new TRD classes
60 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
61 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
63 Revision 1.16 1999/11/05 22:50:28 fca
64 Do not use Atan, removed from ROOT too
66 Revision 1.15 1999/11/02 17:20:19 fca
67 initialise nbytes before using it
69 Revision 1.14 1999/11/02 17:15:54 fca
70 Correct ansi scoping not accepted by HP compilers
72 Revision 1.13 1999/11/02 17:14:51 fca
73 Correct ansi scoping not accepted by HP compilers
75 Revision 1.12 1999/11/02 16:35:56 fca
76 New version of TRD introduced
78 Revision 1.11 1999/11/01 20:41:51 fca
79 Added protections against using the wrong version of FRAME
81 Revision 1.10 1999/09/29 09:24:35 fca
82 Introduction of the Copyright and cvs Log
86 ///////////////////////////////////////////////////////////////////////////////
88 // Transition Radiation Detector version 1 -- slow simulator //
92 <img src="picts/AliTRDfullClass.gif">
97 ///////////////////////////////////////////////////////////////////////////////
105 #include <TLorentzVector.h>
109 #include "AliConst.h"
111 #include "AliTRDv1.h"
112 #include "AliTRDhit.h"
113 #include "AliTRDmatrix.h"
114 #include "AliTRDgeometry.h"
115 #include "AliTRDsim.h"
119 //_____________________________________________________________________________
120 AliTRDv1::AliTRDv1():AliTRD()
123 // Default constructor
136 fSensSectorRange = 0;
143 //_____________________________________________________________________________
144 AliTRDv1::AliTRDv1(const char *name, const char *title)
148 // Standard constructor for Transition Radiation Detector version 1
161 fSensSectorRange = 0;
166 SetBufferSize(128000);
170 //_____________________________________________________________________________
171 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
177 ((AliTRDv1 &) trd).Copy(*this);
181 //_____________________________________________________________________________
182 AliTRDv1::~AliTRDv1()
185 // AliTRDv1 destructor
188 if (fDeltaE) delete fDeltaE;
193 //_____________________________________________________________________________
194 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
197 // Assignment operator
200 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
205 //_____________________________________________________________________________
206 void AliTRDv1::Copy(TObject &trd)
212 ((AliTRDv1 &) trd).fIdSens = fIdSens;
214 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
215 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
216 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
218 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
219 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
220 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
221 ((AliTRDv1 &) trd).fSensSector = fSensSector;
222 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
224 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
225 fTR->Copy(*((AliTRDv1 &) trd).fTR);
229 //_____________________________________________________________________________
230 void AliTRDv1::CreateGeometry()
233 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
234 // This version covers the full azimuth.
237 // Check that FRAME is there otherwise we have no place where to put the TRD
238 AliModule* frame = gAlice->GetModule("FRAME");
241 // Define the chambers
242 AliTRD::CreateGeometry();
246 //_____________________________________________________________________________
247 void AliTRDv1::CreateMaterials()
250 // Create materials for the Transition Radiation Detector version 1
253 AliTRD::CreateMaterials();
257 //_____________________________________________________________________________
258 void AliTRDv1::CreateTRhit(Int_t det)
261 // Creates an electron cluster from a TR photon.
262 // The photon is assumed to be created a the end of the radiator. The
263 // distance after which it deposits its energy takes into account the
264 // absorbtion of the entrance window and of the gas mixture in drift
269 const Int_t kPdgElectron = 11;
272 const Float_t kWion = 22.04;
274 // Maximum number of TR photons per track
275 const Int_t kNTR = 50;
277 TLorentzVector mom, pos;
278 TClonesArray &lhits = *fHits;
280 // Create TR only for electrons
281 Int_t iPdg = gMC->TrackPid();
282 if (TMath::Abs(iPdg) != kPdgElectron) return;
284 // Create TR at the entrance of the chamber
285 if (gMC->IsTrackEntering()) {
291 gMC->TrackMomentum(mom);
292 Float_t pTot = mom.Rho();
293 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
295 printf("AliTRDv1::CreateTRhit -- ");
296 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
300 // Loop through the TR photons
301 for (Int_t iTR = 0; iTR < nTR; iTR++) {
303 Float_t energyMeV = eTR[iTR] * 0.001;
304 Float_t energyeV = eTR[iTR] * 1000.0;
305 Float_t absLength = 0;
308 // Take the absorbtion in the entrance window into account
309 Double_t muMy = fTR->GetMuMy(energyMeV);
310 sigma = muMy * fFoilDensity;
311 absLength = gRandom->Exp(sigma);
312 if (absLength < AliTRDgeometry::MyThick()) continue;
314 // The absorbtion cross sections in the drift gas
316 // Gas-mixture (Xe/CO2)
317 Double_t muXe = fTR->GetMuXe(energyMeV);
318 Double_t muCO = fTR->GetMuCO(energyMeV);
319 sigma = (0.90 * muXe + 0.10 * muCO) * fGasDensity;
322 // Gas-mixture (Xe/Isobutane)
323 Double_t muXe = fTR->GetMuXe(energyMeV);
324 Double_t muBu = fTR->GetMuBu(energyMeV);
325 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
328 // The distance after which the energy of the TR photon
330 absLength = gRandom->Exp(sigma);
331 if (absLength > AliTRDgeometry::DrThick()) continue;
333 // The position of the absorbtion
335 gMC->TrackPosition(pos);
336 posHit[0] = pos[0] + mom[0] / pTot * absLength;
337 posHit[1] = pos[1] + mom[1] / pTot * absLength;
338 posHit[2] = pos[2] + mom[2] / pTot * absLength;
341 Int_t q = ((Int_t) (energyeV / kWion));
343 // Add the hit to the array. TR photon hits are marked
344 // by negative charge
345 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack()
354 //_____________________________________________________________________________
355 void AliTRDv1::Init()
358 // Initialise Transition Radiation Detector after geometry has been built.
363 printf(" Slow simulator\n\n");
366 printf(" Only plane %d is sensitive\n",fSensPlane);
367 if (fSensChamber >= 0)
368 printf(" Only chamber %d is sensitive\n",fSensChamber);
369 if (fSensSector >= 0) {
370 Int_t sens1 = fSensSector;
371 Int_t sens2 = fSensSector + fSensSectorRange;
372 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
373 * AliTRDgeometry::Nsect();
374 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
378 printf(" TR simulation on\n");
380 printf(" TR simulation off\n");
383 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
384 const Float_t kPoti = 12.1;
385 // Maximum energy (50 keV);
386 const Float_t kEend = 50000.0;
387 // Ermilova distribution for the delta-ray spectrum
388 Float_t poti = TMath::Log(kPoti);
389 Float_t eEnd = TMath::Log(kEend);
390 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
392 // Identifier of the sensitive volume (drift region)
393 fIdSens = gMC->VolId("UL05");
395 // Identifier of the TRD-driftchambers
396 fIdChamber1 = gMC->VolId("UCIO");
397 fIdChamber2 = gMC->VolId("UCIM");
398 fIdChamber3 = gMC->VolId("UCII");
400 for (Int_t i = 0; i < 80; i++) printf("*");
405 //_____________________________________________________________________________
406 AliTRDsim *AliTRDv1::CreateTR()
409 // Enables the simulation of TR
412 fTR = new AliTRDsim();
417 //_____________________________________________________________________________
418 void AliTRDv1::SetSensPlane(Int_t iplane)
421 // Defines the hit-sensitive plane (0-5)
424 if ((iplane < 0) || (iplane > 5)) {
425 printf("Wrong input value: %d\n",iplane);
426 printf("Use standard setting\n");
437 //_____________________________________________________________________________
438 void AliTRDv1::SetSensChamber(Int_t ichamber)
441 // Defines the hit-sensitive chamber (0-4)
444 if ((ichamber < 0) || (ichamber > 4)) {
445 printf("Wrong input value: %d\n",ichamber);
446 printf("Use standard setting\n");
453 fSensChamber = ichamber;
457 //_____________________________________________________________________________
458 void AliTRDv1::SetSensSector(Int_t isector)
461 // Defines the hit-sensitive sector (0-17)
464 SetSensSector(isector,1);
468 //_____________________________________________________________________________
469 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
472 // Defines a range of hit-sensitive sectors. The range is defined by
473 // <isector> (0-17) as the starting point and <nsector> as the number
474 // of sectors to be included.
477 if ((isector < 0) || (isector > 17)) {
478 printf("Wrong input value <isector>: %d\n",isector);
479 printf("Use standard setting\n");
481 fSensSectorRange = 0;
486 if ((nsector < 1) || (nsector > 18)) {
487 printf("Wrong input value <nsector>: %d\n",nsector);
488 printf("Use standard setting\n");
490 fSensSectorRange = 0;
496 fSensSector = isector;
497 fSensSectorRange = nsector;
501 //_____________________________________________________________________________
502 void AliTRDv1::StepManager()
505 // Slow simulator. Every charged track produces electron cluster as hits
506 // along its path across the drift volume. The step size is set acording
507 // to Bethe-Bloch. The energy distribution of the delta electrons follows
508 // a spectrum taken from Ermilova et al.
511 Int_t iIdSens, icSens;
512 Int_t iIdSpace, icSpace;
513 Int_t iIdChamber, icChamber;
529 Double_t betaGamma, pp;
531 TLorentzVector pos, mom;
532 TClonesArray &lhits = *fHits;
534 const Double_t kBig = 1.0E+12;
537 const Float_t kWion = 22.04;
538 // Maximum energy for e+ e- g for the step-size calculation
539 const Float_t kPTotMax = 0.002;
540 // Plateau value of the energy-loss for electron in xenon
541 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
542 //const Double_t kPlateau = 1.70;
543 // the averaged value (26/3/99)
544 const Float_t kPlateau = 1.55;
545 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
546 const Float_t kPrim = 48.0;
547 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
548 const Float_t kPoti = 12.1;
551 const Int_t kPdgElectron = 11;
553 // Set the maximum step size to a very large number for all
554 // neutral particles and those outside the driftvolume
555 gMC->SetMaxStep(kBig);
557 // Create some special hits with amplitude 0 at the entrance and
558 // exit of each chamber that contain the momentum components of the particle
559 if (gMC->TrackCharge() &&
560 (gMC->IsTrackEntering() || gMC->IsTrackExiting())) {
562 // Inside a sensitive volume?
563 iIdSens = gMC->CurrentVolID(icSens);
564 if (iIdSens == fIdSens) {
566 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
567 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
569 // The hit coordinates
570 gMC->TrackPosition(pos);
575 // The track momentum
576 gMC->TrackMomentum(mom);
581 // The sector number (0 - 17)
582 // The numbering goes clockwise and starts at y = 0
583 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
588 sec = ((Int_t) (phi / 20));
590 // The chamber number
596 if (iIdChamber == fIdChamber1)
597 cha = (hits[2] < 0 ? 0 : 4);
598 else if (iIdChamber == fIdChamber2)
599 cha = (hits[2] < 0 ? 1 : 3);
600 else if (iIdChamber == fIdChamber3)
604 // The numbering starts at the innermost plane
605 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
607 // Check on selected volumes
608 Int_t addthishit = 1;
610 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
611 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
612 if (fSensSector >= 0) {
613 Int_t sens1 = fSensSector;
614 Int_t sens2 = fSensSector + fSensSectorRange;
615 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
616 * AliTRDgeometry::Nsect();
618 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
621 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
628 det = fGeometry->GetDetector(pla,cha,sec);
629 new(lhits[fNhits++]) AliTRDhit(fIshunt
630 ,gAlice->CurrentTrack()
640 // Use only charged tracks
641 if (( gMC->TrackCharge() ) &&
642 (!gMC->IsTrackStop() ) &&
643 (!gMC->IsTrackDisappeared())) {
645 // Inside a sensitive volume?
646 iIdSens = gMC->CurrentVolID(icSens);
647 if (iIdSens == fIdSens) {
649 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
650 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
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 // The hit coordinates and charge
660 gMC->TrackPosition(pos);
665 // The sector number (0 - 17)
666 // The numbering goes clockwise and starts at y = 0
667 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
672 sec = ((Int_t) (phi / 20));
674 // The chamber number
680 if (iIdChamber == fIdChamber1)
681 cha = (hits[2] < 0 ? 0 : 4);
682 else if (iIdChamber == fIdChamber2)
683 cha = (hits[2] < 0 ? 1 : 3);
684 else if (iIdChamber == fIdChamber3)
688 // The numbering starts at the innermost plane
689 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
691 // Check on selected volumes
692 Int_t addthishit = 1;
694 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
695 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
696 if (fSensSector >= 0) {
697 Int_t sens1 = fSensSector;
698 Int_t sens2 = fSensSector + fSensSectorRange;
699 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
700 * AliTRDgeometry::Nsect();
702 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
705 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
713 det = fGeometry->GetDetector(pla,cha,sec);
715 // Create the electron cluster from TR photons
716 if (fTR) CreateTRhit(det);
718 new(lhits[fNhits++]) AliTRDhit(fIshunt
719 ,gAlice->CurrentTrack()
724 // The energy loss according to Bethe Bloch
725 gMC->TrackMomentum(mom);
727 iPdg = TMath::Abs(gMC->TrackPid());
728 if ( (iPdg != kPdgElectron) ||
729 ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
730 aMass = gMC->TrackMass();
731 betaGamma = pTot / aMass;
732 pp = kPrim * BetheBloch(betaGamma);
733 // Take charge > 1 into account
734 charge = gMC->TrackCharge();
735 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
737 // Electrons above 20 Mev/c are at the plateau
739 pp = kPrim * kPlateau;
742 // Calculate the maximum step size for the next tracking step
746 while ((random[0] == 1.) || (random[0] == 0.));
747 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
752 // set step size to maximal value
753 gMC->SetMaxStep(kBig);
762 //_____________________________________________________________________________
763 Double_t AliTRDv1::BetheBloch(Double_t bg)
766 // Parametrization of the Bethe-Bloch-curve
767 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
770 // This parameters have been adjusted to averaged values from GEANT
771 const Double_t kP1 = 7.17960e-02;
772 const Double_t kP2 = 8.54196;
773 const Double_t kP3 = 1.38065e-06;
774 const Double_t kP4 = 5.30972;
775 const Double_t kP5 = 2.83798;
777 // This parameters have been adjusted to Xe-data found in:
778 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
779 //const Double_t kP1 = 0.76176E-1;
780 //const Double_t kP2 = 10.632;
781 //const Double_t kP3 = 3.17983E-6;
782 //const Double_t kP4 = 1.8631;
783 //const Double_t kP5 = 1.9479;
786 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
787 Double_t aa = TMath::Power(yy,kP4);
788 Double_t bb = TMath::Power((1./bg),kP5);
789 bb = TMath::Log(kP3 + bb);
790 return ((kP2 - aa - bb)*kP1 / aa);
797 //_____________________________________________________________________________
798 Double_t Ermilova(Double_t *x, Double_t *)
801 // Calculates the delta-ray energy distribution according to Ermilova.
802 // Logarithmic scale !
811 const Int_t kNv = 31;
813 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
814 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
815 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
816 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
817 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
818 , 9.4727, 9.9035,10.3735,10.5966,10.8198
821 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
822 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
823 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
824 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
825 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
826 , 0.04 , 0.023, 0.015, 0.011, 0.01
835 dpos = energy - vxe[pos2++];
839 if (pos2 > kNv) pos2 = kNv;
842 // Differentiate between the sampling points
843 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);