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 1.26 2000/11/30 17:38:08 cblume
19 Changes to get in line with new STEER and EVGEN
21 Revision 1.25 2000/11/15 14:30:16 cblume
22 Fixed bug in calculating detector no. of extra hit
24 Revision 1.24 2000/11/10 14:58:36 cblume
25 Introduce additional hit with amplitude 0 at the chamber borders
27 Revision 1.23 2000/11/01 14:53:21 cblume
28 Merge with TRD-develop
30 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
33 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
36 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
37 Replace include files by forward declarations
39 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
40 Include TR photon generation and adapt to new AliTRDhit
42 Revision 1.22 2000/06/27 13:08:50 cblume
43 Changed to Copy(TObject &A) to appease the HP-compiler
45 Revision 1.21 2000/06/09 11:10:07 cblume
46 Compiler warnings and coding conventions, next round
48 Revision 1.20 2000/06/08 18:32:58 cblume
49 Make code compliant to coding conventions
51 Revision 1.19 2000/06/07 16:27:32 cblume
52 Try to remove compiler warnings on Sun and HP
54 Revision 1.18 2000/05/08 16:17:27 cblume
57 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
58 Made inline function non-virtual. Bug fix in setting sensitive chamber
60 Revision 1.17 2000/02/28 19:10:26 cblume
61 Include the new TRD classes
63 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
64 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
66 Revision 1.16 1999/11/05 22:50:28 fca
67 Do not use Atan, removed from ROOT too
69 Revision 1.15 1999/11/02 17:20:19 fca
70 initialise nbytes before using it
72 Revision 1.14 1999/11/02 17:15:54 fca
73 Correct ansi scoping not accepted by HP compilers
75 Revision 1.13 1999/11/02 17:14:51 fca
76 Correct ansi scoping not accepted by HP compilers
78 Revision 1.12 1999/11/02 16:35:56 fca
79 New version of TRD introduced
81 Revision 1.11 1999/11/01 20:41:51 fca
82 Added protections against using the wrong version of FRAME
84 Revision 1.10 1999/09/29 09:24:35 fca
85 Introduction of the Copyright and cvs Log
89 ///////////////////////////////////////////////////////////////////////////////
91 // Transition Radiation Detector version 1 -- slow simulator //
95 <img src="picts/AliTRDfullClass.gif">
100 ///////////////////////////////////////////////////////////////////////////////
108 #include <TLorentzVector.h>
112 #include "AliConst.h"
114 #include "AliTRDv1.h"
115 #include "AliTRDhit.h"
116 #include "AliTRDmatrix.h"
117 #include "AliTRDgeometry.h"
118 #include "AliTRDsim.h"
122 //_____________________________________________________________________________
123 AliTRDv1::AliTRDv1():AliTRD()
126 // Default constructor
139 fSensSectorRange = 0;
146 //_____________________________________________________________________________
147 AliTRDv1::AliTRDv1(const char *name, const char *title)
151 // Standard constructor for Transition Radiation Detector version 1
164 fSensSectorRange = 0;
169 SetBufferSize(128000);
173 //_____________________________________________________________________________
174 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
180 ((AliTRDv1 &) trd).Copy(*this);
184 //_____________________________________________________________________________
185 AliTRDv1::~AliTRDv1()
188 // AliTRDv1 destructor
191 if (fDeltaE) delete fDeltaE;
196 //_____________________________________________________________________________
197 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
200 // Assignment operator
203 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
208 //_____________________________________________________________________________
209 void AliTRDv1::Copy(TObject &trd)
215 ((AliTRDv1 &) trd).fIdSens = fIdSens;
217 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
218 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
219 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
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;
281 TClonesArray &lhits = *fHits;
283 // Create TR only for electrons
284 Int_t iPdg = gMC->TrackPid();
285 if (TMath::Abs(iPdg) != kPdgElectron) return;
287 // Create TR at the entrance of the chamber
288 if (gMC->IsTrackEntering()) {
294 gMC->TrackMomentum(mom);
295 Float_t pTot = mom.Rho();
296 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
298 printf("AliTRDv1::CreateTRhit -- ");
299 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
303 // Loop through the TR photons
304 for (Int_t iTR = 0; iTR < nTR; iTR++) {
306 Float_t energyMeV = eTR[iTR] * 0.001;
307 Float_t energyeV = eTR[iTR] * 1000.0;
308 Float_t absLength = 0;
311 // Take the absorbtion in the entrance window into account
312 Double_t muMy = fTR->GetMuMy(energyMeV);
313 sigma = muMy * fFoilDensity;
314 absLength = gRandom->Exp(sigma);
315 if (absLength < AliTRDgeometry::MyThick()) continue;
317 // The absorbtion cross sections in the drift gas
319 // Gas-mixture (Xe/CO2)
320 Double_t muXe = fTR->GetMuXe(energyMeV);
321 Double_t muCO = fTR->GetMuCO(energyMeV);
322 sigma = (0.90 * muXe + 0.10 * muCO) * fGasDensity;
325 // Gas-mixture (Xe/Isobutane)
326 Double_t muXe = fTR->GetMuXe(energyMeV);
327 Double_t muBu = fTR->GetMuBu(energyMeV);
328 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
331 // The distance after which the energy of the TR photon
333 absLength = gRandom->Exp(sigma);
334 if (absLength > AliTRDgeometry::DrThick()) continue;
336 // The position of the absorbtion
338 gMC->TrackPosition(pos);
339 posHit[0] = pos[0] + mom[0] / pTot * absLength;
340 posHit[1] = pos[1] + mom[1] / pTot * absLength;
341 posHit[2] = pos[2] + mom[2] / pTot * absLength;
344 Int_t q = ((Int_t) (energyeV / kWion));
346 // Add the hit to the array. TR photon hits are marked
347 // by negative charge
348 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack()
357 //_____________________________________________________________________________
358 void AliTRDv1::Init()
361 // Initialise Transition Radiation Detector after geometry has been built.
366 printf(" Slow simulator\n\n");
369 printf(" Only plane %d is sensitive\n",fSensPlane);
370 if (fSensChamber >= 0)
371 printf(" Only chamber %d is sensitive\n",fSensChamber);
372 if (fSensSector >= 0) {
373 Int_t sens1 = fSensSector;
374 Int_t sens2 = fSensSector + fSensSectorRange;
375 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
376 * AliTRDgeometry::Nsect();
377 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
381 printf(" TR simulation on\n");
383 printf(" TR simulation off\n");
386 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
387 const Float_t kPoti = 12.1;
388 // Maximum energy (50 keV);
389 const Float_t kEend = 50000.0;
390 // Ermilova distribution for the delta-ray spectrum
391 Float_t poti = TMath::Log(kPoti);
392 Float_t eEnd = TMath::Log(kEend);
393 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
395 // Identifier of the sensitive volume (drift region)
396 fIdSens = gMC->VolId("UL05");
398 // Identifier of the TRD-driftchambers
399 fIdChamber1 = gMC->VolId("UCIO");
400 fIdChamber2 = gMC->VolId("UCIM");
401 fIdChamber3 = gMC->VolId("UCII");
403 for (Int_t i = 0; i < 80; i++) printf("*");
408 //_____________________________________________________________________________
409 AliTRDsim *AliTRDv1::CreateTR()
412 // Enables the simulation of TR
415 fTR = new AliTRDsim();
420 //_____________________________________________________________________________
421 void AliTRDv1::SetSensPlane(Int_t iplane)
424 // Defines the hit-sensitive plane (0-5)
427 if ((iplane < 0) || (iplane > 5)) {
428 printf("Wrong input value: %d\n",iplane);
429 printf("Use standard setting\n");
440 //_____________________________________________________________________________
441 void AliTRDv1::SetSensChamber(Int_t ichamber)
444 // Defines the hit-sensitive chamber (0-4)
447 if ((ichamber < 0) || (ichamber > 4)) {
448 printf("Wrong input value: %d\n",ichamber);
449 printf("Use standard setting\n");
456 fSensChamber = ichamber;
460 //_____________________________________________________________________________
461 void AliTRDv1::SetSensSector(Int_t isector)
464 // Defines the hit-sensitive sector (0-17)
467 SetSensSector(isector,1);
471 //_____________________________________________________________________________
472 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
475 // Defines a range of hit-sensitive sectors. The range is defined by
476 // <isector> (0-17) as the starting point and <nsector> as the number
477 // of sectors to be included.
480 if ((isector < 0) || (isector > 17)) {
481 printf("Wrong input value <isector>: %d\n",isector);
482 printf("Use standard setting\n");
484 fSensSectorRange = 0;
489 if ((nsector < 1) || (nsector > 18)) {
490 printf("Wrong input value <nsector>: %d\n",nsector);
491 printf("Use standard setting\n");
493 fSensSectorRange = 0;
499 fSensSector = isector;
500 fSensSectorRange = nsector;
504 //_____________________________________________________________________________
505 void AliTRDv1::StepManager()
508 // Slow simulator. Every charged track produces electron cluster as hits
509 // along its path across the drift volume. The step size is set acording
510 // to Bethe-Bloch. The energy distribution of the delta electrons follows
511 // a spectrum taken from Ermilova et al.
514 Int_t iIdSens, icSens;
515 Int_t iIdSpace, icSpace;
516 Int_t iIdChamber, icChamber;
532 Double_t betaGamma, pp;
534 TLorentzVector pos, mom;
535 TClonesArray &lhits = *fHits;
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 momentum for the step size adjustment
544 const Float_t kPTotMinStep = 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 // Create some special hits with amplitude 0 at the entrance and
563 // exit of each chamber that contain the momentum components of the particle
564 if (gMC->TrackCharge() &&
565 (gMC->IsTrackEntering() || gMC->IsTrackExiting())) {
567 // Inside a sensitive volume?
568 iIdSens = gMC->CurrentVolID(icSens);
569 if (iIdSens == fIdSens) {
571 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
572 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
574 // The hit coordinates
575 gMC->TrackPosition(pos);
580 // The track momentum
581 gMC->TrackMomentum(mom);
586 // The sector number (0 - 17)
587 // The numbering goes clockwise and starts at y = 0
588 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
593 sec = ((Int_t) (phi / 20));
595 // The chamber number
601 if (iIdChamber == fIdChamber1)
602 cha = (hits[2] < 0 ? 0 : 4);
603 else if (iIdChamber == fIdChamber2)
604 cha = (hits[2] < 0 ? 1 : 3);
605 else if (iIdChamber == fIdChamber3)
609 // The numbering starts at the innermost plane
610 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
612 // Check on selected volumes
613 Int_t addthishit = 1;
615 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
616 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
617 if (fSensSector >= 0) {
618 Int_t sens1 = fSensSector;
619 Int_t sens2 = fSensSector + fSensSectorRange;
620 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
621 * AliTRDgeometry::Nsect();
623 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
626 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
633 det = fGeometry->GetDetector(pla,cha,sec);
634 new(lhits[fNhits++]) AliTRDhit(fIshunt
635 ,gAlice->CurrentTrack()
645 // Use only charged tracks
646 if (( gMC->TrackCharge() ) &&
647 (!gMC->IsTrackStop() ) &&
648 (!gMC->IsTrackDisappeared())) {
650 // Inside a sensitive volume?
651 iIdSens = gMC->CurrentVolID(icSens);
652 if (iIdSens == fIdSens) {
654 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
655 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
657 // Calculate the energy of the delta-electrons
658 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
659 eDelta = TMath::Max(eDelta,0.0);
661 // The number of secondary electrons created
662 qTot = ((Int_t) (eDelta / kWion) + 1);
664 // The hit coordinates and charge
665 gMC->TrackPosition(pos);
670 // The sector number (0 - 17)
671 // The numbering goes clockwise and starts at y = 0
672 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
677 sec = ((Int_t) (phi / 20));
679 // The chamber number
685 if (iIdChamber == fIdChamber1)
686 cha = (hits[2] < 0 ? 0 : 4);
687 else if (iIdChamber == fIdChamber2)
688 cha = (hits[2] < 0 ? 1 : 3);
689 else if (iIdChamber == fIdChamber3)
693 // The numbering starts at the innermost plane
694 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
696 // Check on selected volumes
697 Int_t addthishit = 1;
699 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
700 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
701 if (fSensSector >= 0) {
702 Int_t sens1 = fSensSector;
703 Int_t sens2 = fSensSector + fSensSectorRange;
704 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
705 * AliTRDgeometry::Nsect();
707 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
710 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
718 det = fGeometry->GetDetector(pla,cha,sec);
720 // Create the electron cluster from TR photons
721 if (fTR) CreateTRhit(det);
723 new(lhits[fNhits++]) AliTRDhit(fIshunt
724 ,gAlice->CurrentTrack()
729 // The energy loss according to Bethe Bloch
730 gMC->TrackMomentum(mom);
732 iPdg = TMath::Abs(gMC->TrackPid());
733 if ( (iPdg != kPdgElectron) ||
734 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
735 aMass = gMC->TrackMass();
736 betaGamma = pTot / aMass;
737 pp = kPrim * BetheBloch(betaGamma);
738 // Take charge > 1 into account
739 charge = gMC->TrackCharge();
740 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
742 // Electrons above 20 Mev/c are at the plateau
744 pp = kPrim * kPlateau;
747 // Calculate the maximum step size for the next tracking step
748 // introduce a lower momentum cut
749 //if ((pp > 0) && (pTot > kPTotMinStep)) {
753 while ((random[0] == 1.) || (random[0] == 0.));
754 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
759 // set step size to maximal value
760 gMC->SetMaxStep(kBig);
769 //_____________________________________________________________________________
770 Double_t AliTRDv1::BetheBloch(Double_t bg)
773 // Parametrization of the Bethe-Bloch-curve
774 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
777 // This parameters have been adjusted to averaged values from GEANT
778 const Double_t kP1 = 7.17960e-02;
779 const Double_t kP2 = 8.54196;
780 const Double_t kP3 = 1.38065e-06;
781 const Double_t kP4 = 5.30972;
782 const Double_t kP5 = 2.83798;
784 // This parameters have been adjusted to Xe-data found in:
785 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
786 //const Double_t kP1 = 0.76176E-1;
787 //const Double_t kP2 = 10.632;
788 //const Double_t kP3 = 3.17983E-6;
789 //const Double_t kP4 = 1.8631;
790 //const Double_t kP5 = 1.9479;
793 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
794 Double_t aa = TMath::Power(yy,kP4);
795 Double_t bb = TMath::Power((1./bg),kP5);
796 bb = TMath::Log(kP3 + bb);
797 return ((kP2 - aa - bb)*kP1 / aa);
804 //_____________________________________________________________________________
805 Double_t Ermilova(Double_t *x, Double_t *)
808 // Calculates the delta-ray energy distribution according to Ermilova.
809 // Logarithmic scale !
818 const Int_t kNv = 31;
820 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
821 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
822 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
823 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
824 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
825 , 9.4727, 9.9035,10.3735,10.5966,10.8198
828 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
829 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
830 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
831 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
832 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
833 , 0.04 , 0.023, 0.015, 0.011, 0.01
842 dpos = energy - vxe[pos2++];
846 if (pos2 > kNv) pos2 = kNv;
849 // Differentiate between the sampling points
850 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);