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 1.41 2003/04/23 15:19:48 cblume
19 Fix bug in absorbtion length of photons
21 Revision 1.40 2003/04/08 08:14:53 morsch
22 AddTrackReference moved to AliModule.
24 Revision 1.39 2003/02/11 16:54:07 hristov
25 Updated AliTrackReference class (S.Radomski)
27 Revision 1.38 2003/01/31 11:41:06 cblume
28 Fix bug in StepManager in treating geometry with holes
30 Revision 1.37 2003/01/28 14:38:18 cblume
31 Add track length to track references
33 Revision 1.36 2002/11/21 22:38:47 alibrary
34 Removing AliMC and AliMCProcess
36 Revision 1.35 2002/10/14 14:57:44 hristov
37 Merging the VirtualMC branch to the main development branch (HEAD)
39 Revision 1.33.6.2 2002/07/24 10:09:31 alibrary
42 Revision 1.34 2002/06/13 08:11:56 cblume
43 Add the track references
45 Revision 1.33 2002/02/20 14:01:40 hristov
46 Compare a TString with a string, otherwise the conversion cannot be done on Sun
48 Revision 1.32 2002/02/13 16:58:37 cblume
49 Bug fix reported by Jiri. Make atoi input zero terminated in StepManager()
51 Revision 1.31 2002/02/11 14:25:27 cblume
52 Geometry update, compressed hit structure
54 Revision 1.30 2001/05/21 16:45:47 hristov
55 Last minute changes (C.Blume)
57 Revision 1.29 2001/05/16 14:57:28 alibrary
58 New files for folders and Stack
60 Revision 1.28 2001/05/07 08:03:22 cblume
61 Generate also hits in the amplification region
63 Revision 1.27 2001/03/30 14:40:15 cblume
64 Update of the digitization parameter
66 Revision 1.26 2000/11/30 17:38:08 cblume
67 Changes to get in line with new STEER and EVGEN
69 Revision 1.25 2000/11/15 14:30:16 cblume
70 Fixed bug in calculating detector no. of extra hit
72 Revision 1.24 2000/11/10 14:58:36 cblume
73 Introduce additional hit with amplitude 0 at the chamber borders
75 Revision 1.23 2000/11/01 14:53:21 cblume
76 Merge with TRD-develop
78 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
81 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
84 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
85 Replace include files by forward declarations
87 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
88 Include TR photon generation and adapt to new AliTRDhit
90 Revision 1.22 2000/06/27 13:08:50 cblume
91 Changed to Copy(TObject &A) to appease the HP-compiler
93 Revision 1.21 2000/06/09 11:10:07 cblume
94 Compiler warnings and coding conventions, next round
96 Revision 1.20 2000/06/08 18:32:58 cblume
97 Make code compliant to coding conventions
99 Revision 1.19 2000/06/07 16:27:32 cblume
100 Try to remove compiler warnings on Sun and HP
102 Revision 1.18 2000/05/08 16:17:27 cblume
105 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
106 Made inline function non-virtual. Bug fix in setting sensitive chamber
108 Revision 1.17 2000/02/28 19:10:26 cblume
109 Include the new TRD classes
111 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
112 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
114 Revision 1.16 1999/11/05 22:50:28 fca
115 Do not use Atan, removed from ROOT too
117 Revision 1.15 1999/11/02 17:20:19 fca
118 initialise nbytes before using it
120 Revision 1.14 1999/11/02 17:15:54 fca
121 Correct ansi scoping not accepted by HP compilers
123 Revision 1.13 1999/11/02 17:14:51 fca
124 Correct ansi scoping not accepted by HP compilers
126 Revision 1.12 1999/11/02 16:35:56 fca
127 New version of TRD introduced
129 Revision 1.11 1999/11/01 20:41:51 fca
130 Added protections against using the wrong version of FRAME
132 Revision 1.10 1999/09/29 09:24:35 fca
133 Introduction of the Copyright and cvs Log
137 ///////////////////////////////////////////////////////////////////////////////
139 // Transition Radiation Detector version 1 -- slow simulator //
143 <img src="picts/AliTRDfullClass.gif">
148 ///////////////////////////////////////////////////////////////////////////////
156 #include <TLorentzVector.h>
159 #include "AliConst.h"
161 #include "AliTRDv1.h"
162 #include "AliTRDhit.h"
163 #include "AliTRDmatrix.h"
164 #include "AliTRDgeometry.h"
165 #include "AliTRDsim.h"
169 //_____________________________________________________________________________
170 AliTRDv1::AliTRDv1():AliTRD()
173 // Default constructor
180 fSensSectorRange = 0;
187 //_____________________________________________________________________________
188 AliTRDv1::AliTRDv1(const char *name, const char *title)
192 // Standard constructor for Transition Radiation Detector version 1
199 fSensSectorRange = 0;
204 SetBufferSize(128000);
208 //_____________________________________________________________________________
209 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
215 ((AliTRDv1 &) trd).Copy(*this);
219 //_____________________________________________________________________________
220 AliTRDv1::~AliTRDv1()
223 // AliTRDv1 destructor
226 if (fDeltaE) delete fDeltaE;
231 //_____________________________________________________________________________
232 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
235 // Assignment operator
238 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
243 //_____________________________________________________________________________
244 void AliTRDv1::Copy(TObject &trd)
250 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
251 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
252 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
253 ((AliTRDv1 &) trd).fSensSector = fSensSector;
254 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
256 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
257 fTR->Copy(*((AliTRDv1 &) trd).fTR);
261 //_____________________________________________________________________________
262 void AliTRDv1::CreateGeometry()
265 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
266 // This version covers the full azimuth.
269 // Check that FRAME is there otherwise we have no place where to put the TRD
270 AliModule* frame = gAlice->GetModule("FRAME");
273 // Define the chambers
274 AliTRD::CreateGeometry();
278 //_____________________________________________________________________________
279 void AliTRDv1::CreateMaterials()
282 // Create materials for the Transition Radiation Detector version 1
285 AliTRD::CreateMaterials();
289 //_____________________________________________________________________________
290 void AliTRDv1::CreateTRhit(Int_t det)
293 // Creates an electron cluster from a TR photon.
294 // The photon is assumed to be created a the end of the radiator. The
295 // distance after which it deposits its energy takes into account the
296 // absorbtion of the entrance window and of the gas mixture in drift
301 const Int_t kPdgElectron = 11;
304 const Float_t kWion = 22.04;
306 // Maximum number of TR photons per track
307 const Int_t kNTR = 50;
309 TLorentzVector mom, pos;
311 // Create TR at the entrance of the chamber
312 if (gMC->IsTrackEntering()) {
314 // Create TR only for electrons
315 Int_t iPdg = gMC->TrackPid();
316 if (TMath::Abs(iPdg) != kPdgElectron) return;
322 gMC->TrackMomentum(mom);
323 Float_t pTot = mom.Rho();
324 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
326 printf("AliTRDv1::CreateTRhit -- ");
327 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
331 // Loop through the TR photons
332 for (Int_t iTR = 0; iTR < nTR; iTR++) {
334 Float_t energyMeV = eTR[iTR] * 0.001;
335 Float_t energyeV = eTR[iTR] * 1000.0;
336 Float_t absLength = 0;
339 // Take the absorbtion in the entrance window into account
340 Double_t muMy = fTR->GetMuMy(energyMeV);
341 sigma = muMy * fFoilDensity;
343 absLength = gRandom->Exp(1.0/sigma);
344 if (absLength < AliTRDgeometry::MyThick()) continue;
350 // The absorbtion cross sections in the drift gas
352 // Gas-mixture (Xe/CO2)
353 Double_t muXe = fTR->GetMuXe(energyMeV);
354 Double_t muCO = fTR->GetMuCO(energyMeV);
355 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity * fTR->GetTemp();
358 // Gas-mixture (Xe/Isobutane)
359 Double_t muXe = fTR->GetMuXe(energyMeV);
360 Double_t muBu = fTR->GetMuBu(energyMeV);
361 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity * fTR->GetTemp();
364 // The distance after which the energy of the TR photon
367 absLength = gRandom->Exp(1.0/sigma);
368 if (absLength > AliTRDgeometry::DrThick()) continue;
374 // The position of the absorbtion
376 gMC->TrackPosition(pos);
377 posHit[0] = pos[0] + mom[0] / pTot * absLength;
378 posHit[1] = pos[1] + mom[1] / pTot * absLength;
379 posHit[2] = pos[2] + mom[2] / pTot * absLength;
382 Int_t q = ((Int_t) (energyeV / kWion));
384 // Add the hit to the array. TR photon hits are marked
385 // by negative charge
386 AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
394 //_____________________________________________________________________________
395 void AliTRDv1::Init()
398 // Initialise Transition Radiation Detector after geometry has been built.
403 if(fDebug) printf("%s: Slow simulator\n",ClassName());
406 printf(" Only plane %d is sensitive\n",fSensPlane);
407 if (fSensChamber >= 0)
408 printf(" Only chamber %d is sensitive\n",fSensChamber);
409 if (fSensSector >= 0) {
410 Int_t sens1 = fSensSector;
411 Int_t sens2 = fSensSector + fSensSectorRange;
412 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
413 * AliTRDgeometry::Nsect();
414 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
418 printf("%s: TR simulation on\n",ClassName());
420 printf("%s: TR simulation off\n",ClassName());
423 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
424 const Float_t kPoti = 12.1;
425 // Maximum energy (50 keV);
426 const Float_t kEend = 50000.0;
427 // Ermilova distribution for the delta-ray spectrum
428 Float_t poti = TMath::Log(kPoti);
429 Float_t eEnd = TMath::Log(kEend);
430 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
433 printf("%s: ",ClassName());
434 for (Int_t i = 0; i < 80; i++) printf("*");
440 //_____________________________________________________________________________
441 AliTRDsim *AliTRDv1::CreateTR()
444 // Enables the simulation of TR
447 fTR = new AliTRDsim();
452 //_____________________________________________________________________________
453 void AliTRDv1::SetSensPlane(Int_t iplane)
456 // Defines the hit-sensitive plane (0-5)
459 if ((iplane < 0) || (iplane > 5)) {
460 printf("Wrong input value: %d\n",iplane);
461 printf("Use standard setting\n");
472 //_____________________________________________________________________________
473 void AliTRDv1::SetSensChamber(Int_t ichamber)
476 // Defines the hit-sensitive chamber (0-4)
479 if ((ichamber < 0) || (ichamber > 4)) {
480 printf("Wrong input value: %d\n",ichamber);
481 printf("Use standard setting\n");
488 fSensChamber = ichamber;
492 //_____________________________________________________________________________
493 void AliTRDv1::SetSensSector(Int_t isector)
496 // Defines the hit-sensitive sector (0-17)
499 SetSensSector(isector,1);
503 //_____________________________________________________________________________
504 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
507 // Defines a range of hit-sensitive sectors. The range is defined by
508 // <isector> (0-17) as the starting point and <nsector> as the number
509 // of sectors to be included.
512 if ((isector < 0) || (isector > 17)) {
513 printf("Wrong input value <isector>: %d\n",isector);
514 printf("Use standard setting\n");
516 fSensSectorRange = 0;
521 if ((nsector < 1) || (nsector > 18)) {
522 printf("Wrong input value <nsector>: %d\n",nsector);
523 printf("Use standard setting\n");
525 fSensSectorRange = 0;
531 fSensSector = isector;
532 fSensSectorRange = nsector;
536 //_____________________________________________________________________________
537 void AliTRDv1::StepManager()
540 // Slow simulator. Every charged track produces electron cluster as hits
541 // along its path across the drift volume. The step size is set acording
542 // to Bethe-Bloch. The energy distribution of the delta electrons follows
543 // a spectrum taken from Ermilova et al.
560 Double_t betaGamma, pp;
563 Bool_t drRegion = kFALSE;
564 Bool_t amRegion = kFALSE;
567 TString cIdSensDr = "J";
568 TString cIdSensAm = "K";
569 Char_t cIdChamber[3];
572 TLorentzVector pos, mom;
574 const Int_t kNplan = AliTRDgeometry::Nplan();
575 const Int_t kNcham = AliTRDgeometry::Ncham();
576 const Int_t kNdetsec = kNplan * kNcham;
578 const Double_t kBig = 1.0E+12;
581 const Float_t kWion = 22.04;
582 // Maximum momentum for e+ e- g
583 const Float_t kPTotMaxEl = 0.002;
584 // Minimum energy for the step size adjustment
585 const Float_t kEkinMinStep = 1.0e-5;
586 // Plateau value of the energy-loss for electron in xenon
587 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
588 //const Double_t kPlateau = 1.70;
589 // the averaged value (26/3/99)
590 const Float_t kPlateau = 1.55;
591 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
592 const Float_t kPrim = 48.0;
593 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
594 const Float_t kPoti = 12.1;
597 const Int_t kPdgElectron = 11;
599 // Set the maximum step size to a very large number for all
600 // neutral particles and those outside the driftvolume
601 gMC->SetMaxStep(kBig);
603 // Use only charged tracks
604 if (( gMC->TrackCharge() ) &&
605 (!gMC->IsTrackStop() ) &&
606 (!gMC->IsTrackDisappeared())) {
608 // Inside a sensitive volume?
611 cIdCurrent = gMC->CurrentVolName();
612 if (cIdSensDr == cIdCurrent[1]) {
615 if (cIdSensAm == cIdCurrent[1]) {
618 if (drRegion || amRegion) {
620 // The hit coordinates and charge
621 gMC->TrackPosition(pos);
626 // The sector number (0 - 17)
627 // The numbering goes clockwise and starts at y = 0
628 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
633 sec = ((Int_t) (phi / 20));
635 // The plane and chamber number
636 cIdChamber[0] = cIdCurrent[2];
637 cIdChamber[1] = cIdCurrent[3];
638 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
639 cha = ((Int_t) idChamber / kNplan);
640 pla = ((Int_t) idChamber % kNplan);
642 // Check on selected volumes
643 Int_t addthishit = 1;
645 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
646 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
647 if (fSensSector >= 0) {
648 Int_t sens1 = fSensSector;
649 Int_t sens2 = fSensSector + fSensSectorRange;
650 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
651 * AliTRDgeometry::Nsect();
653 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
656 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
664 // The detector number
665 det = fGeometry->GetDetector(pla,cha,sec);
667 // Special hits and TR photons only in the drift region
670 // Create a track reference at the entrance and
671 // exit of each chamber that contain the
672 // momentum components of the particle
673 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
674 gMC->TrackMomentum(mom);
675 AddTrackReference(gAlice->CurrentTrack());
678 // Create the hits from TR photons
679 if (fTR) CreateTRhit(det);
683 // Calculate the energy of the delta-electrons
684 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
685 eDelta = TMath::Max(eDelta,0.0);
687 // The number of secondary electrons created
688 qTot = ((Int_t) (eDelta / kWion) + 1);
690 // Create a new dEdx hit
692 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
695 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
698 // Calculate the maximum step size for the next tracking step
699 // Produce only one hit if Ekin is below cutoff
700 aMass = gMC->TrackMass();
701 if ((gMC->Etot() - aMass) > kEkinMinStep) {
703 // The energy loss according to Bethe Bloch
704 iPdg = TMath::Abs(gMC->TrackPid());
705 if ( (iPdg != kPdgElectron) ||
706 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
707 gMC->TrackMomentum(mom);
709 betaGamma = pTot / aMass;
710 pp = kPrim * BetheBloch(betaGamma);
711 // Take charge > 1 into account
712 charge = gMC->TrackCharge();
713 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
715 // Electrons above 20 Mev/c are at the plateau
717 pp = kPrim * kPlateau;
722 gMC->GetRandom()->RndmArray(1, random);
723 while ((random[0] == 1.) || (random[0] == 0.));
724 stepSize = - TMath::Log(random[0]) / pp;
725 gMC->SetMaxStep(stepSize);
738 //_____________________________________________________________________________
739 Double_t AliTRDv1::BetheBloch(Double_t bg)
742 // Parametrization of the Bethe-Bloch-curve
743 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
746 // This parameters have been adjusted to averaged values from GEANT
747 const Double_t kP1 = 7.17960e-02;
748 const Double_t kP2 = 8.54196;
749 const Double_t kP3 = 1.38065e-06;
750 const Double_t kP4 = 5.30972;
751 const Double_t kP5 = 2.83798;
753 // This parameters have been adjusted to Xe-data found in:
754 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
755 //const Double_t kP1 = 0.76176E-1;
756 //const Double_t kP2 = 10.632;
757 //const Double_t kP3 = 3.17983E-6;
758 //const Double_t kP4 = 1.8631;
759 //const Double_t kP5 = 1.9479;
761 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
762 const Double_t kBgMin = 0.8;
763 const Double_t kBBMax = 6.83298;
764 //const Double_t kBgMin = 0.6;
765 //const Double_t kBBMax = 17.2809;
766 //const Double_t kBgMin = 0.4;
767 //const Double_t kBBMax = 82.0;
770 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
771 Double_t aa = TMath::Power(yy,kP4);
772 Double_t bb = TMath::Power((1./bg),kP5);
773 bb = TMath::Log(kP3 + bb);
774 return ((kP2 - aa - bb)*kP1 / aa);
782 //_____________________________________________________________________________
783 Double_t Ermilova(Double_t *x, Double_t *)
786 // Calculates the delta-ray energy distribution according to Ermilova.
787 // Logarithmic scale !
796 const Int_t kNv = 31;
798 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
799 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
800 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
801 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
802 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
803 , 9.4727, 9.9035,10.3735,10.5966,10.8198
806 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
807 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
808 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
809 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
810 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
811 , 0.04 , 0.023, 0.015, 0.011, 0.01
820 dpos = energy - vxe[pos2++];
824 if (pos2 > kNv) pos2 = kNv - 1;
827 // Differentiate between the sampling points
828 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);