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 1.38 2003/01/31 11:41:06 cblume
19 Fix bug in StepManager in treating geometry with holes
21 Revision 1.37 2003/01/28 14:38:18 cblume
22 Add track length to track references
24 Revision 1.36 2002/11/21 22:38:47 alibrary
25 Removing AliMC and AliMCProcess
27 Revision 1.35 2002/10/14 14:57:44 hristov
28 Merging the VirtualMC branch to the main development branch (HEAD)
30 Revision 1.33.6.2 2002/07/24 10:09:31 alibrary
33 Revision 1.34 2002/06/13 08:11:56 cblume
34 Add the track references
36 Revision 1.33 2002/02/20 14:01:40 hristov
37 Compare a TString with a string, otherwise the conversion cannot be done on Sun
39 Revision 1.32 2002/02/13 16:58:37 cblume
40 Bug fix reported by Jiri. Make atoi input zero terminated in StepManager()
42 Revision 1.31 2002/02/11 14:25:27 cblume
43 Geometry update, compressed hit structure
45 Revision 1.30 2001/05/21 16:45:47 hristov
46 Last minute changes (C.Blume)
48 Revision 1.29 2001/05/16 14:57:28 alibrary
49 New files for folders and Stack
51 Revision 1.28 2001/05/07 08:03:22 cblume
52 Generate also hits in the amplification region
54 Revision 1.27 2001/03/30 14:40:15 cblume
55 Update of the digitization parameter
57 Revision 1.26 2000/11/30 17:38:08 cblume
58 Changes to get in line with new STEER and EVGEN
60 Revision 1.25 2000/11/15 14:30:16 cblume
61 Fixed bug in calculating detector no. of extra hit
63 Revision 1.24 2000/11/10 14:58:36 cblume
64 Introduce additional hit with amplitude 0 at the chamber borders
66 Revision 1.23 2000/11/01 14:53:21 cblume
67 Merge with TRD-develop
69 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
72 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
75 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
76 Replace include files by forward declarations
78 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
79 Include TR photon generation and adapt to new AliTRDhit
81 Revision 1.22 2000/06/27 13:08:50 cblume
82 Changed to Copy(TObject &A) to appease the HP-compiler
84 Revision 1.21 2000/06/09 11:10:07 cblume
85 Compiler warnings and coding conventions, next round
87 Revision 1.20 2000/06/08 18:32:58 cblume
88 Make code compliant to coding conventions
90 Revision 1.19 2000/06/07 16:27:32 cblume
91 Try to remove compiler warnings on Sun and HP
93 Revision 1.18 2000/05/08 16:17:27 cblume
96 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
97 Made inline function non-virtual. Bug fix in setting sensitive chamber
99 Revision 1.17 2000/02/28 19:10:26 cblume
100 Include the new TRD classes
102 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
103 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
105 Revision 1.16 1999/11/05 22:50:28 fca
106 Do not use Atan, removed from ROOT too
108 Revision 1.15 1999/11/02 17:20:19 fca
109 initialise nbytes before using it
111 Revision 1.14 1999/11/02 17:15:54 fca
112 Correct ansi scoping not accepted by HP compilers
114 Revision 1.13 1999/11/02 17:14:51 fca
115 Correct ansi scoping not accepted by HP compilers
117 Revision 1.12 1999/11/02 16:35:56 fca
118 New version of TRD introduced
120 Revision 1.11 1999/11/01 20:41:51 fca
121 Added protections against using the wrong version of FRAME
123 Revision 1.10 1999/09/29 09:24:35 fca
124 Introduction of the Copyright and cvs Log
128 ///////////////////////////////////////////////////////////////////////////////
130 // Transition Radiation Detector version 1 -- slow simulator //
134 <img src="picts/AliTRDfullClass.gif">
139 ///////////////////////////////////////////////////////////////////////////////
147 #include <TLorentzVector.h>
150 #include "AliConst.h"
152 #include "AliTRDv1.h"
153 #include "AliTRDhit.h"
154 #include "AliTRDmatrix.h"
155 #include "AliTRDgeometry.h"
156 #include "AliTRDsim.h"
160 //_____________________________________________________________________________
161 AliTRDv1::AliTRDv1():AliTRD()
164 // Default constructor
171 fSensSectorRange = 0;
178 //_____________________________________________________________________________
179 AliTRDv1::AliTRDv1(const char *name, const char *title)
183 // Standard constructor for Transition Radiation Detector version 1
190 fSensSectorRange = 0;
195 SetBufferSize(128000);
199 //_____________________________________________________________________________
200 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
206 ((AliTRDv1 &) trd).Copy(*this);
210 //_____________________________________________________________________________
211 AliTRDv1::~AliTRDv1()
214 // AliTRDv1 destructor
217 if (fDeltaE) delete fDeltaE;
222 //_____________________________________________________________________________
223 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
226 // Assignment operator
229 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
234 //_____________________________________________________________________________
235 void AliTRDv1::Copy(TObject &trd)
241 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
242 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
243 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
244 ((AliTRDv1 &) trd).fSensSector = fSensSector;
245 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
247 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
248 fTR->Copy(*((AliTRDv1 &) trd).fTR);
252 //_____________________________________________________________________________
253 void AliTRDv1::CreateGeometry()
256 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
257 // This version covers the full azimuth.
260 // Check that FRAME is there otherwise we have no place where to put the TRD
261 AliModule* frame = gAlice->GetModule("FRAME");
264 // Define the chambers
265 AliTRD::CreateGeometry();
269 //_____________________________________________________________________________
270 void AliTRDv1::CreateMaterials()
273 // Create materials for the Transition Radiation Detector version 1
276 AliTRD::CreateMaterials();
280 //_____________________________________________________________________________
281 void AliTRDv1::CreateTRhit(Int_t det)
284 // Creates an electron cluster from a TR photon.
285 // The photon is assumed to be created a the end of the radiator. The
286 // distance after which it deposits its energy takes into account the
287 // absorbtion of the entrance window and of the gas mixture in drift
292 const Int_t kPdgElectron = 11;
295 const Float_t kWion = 22.04;
297 // Maximum number of TR photons per track
298 const Int_t kNTR = 50;
300 TLorentzVector mom, pos;
302 // Create TR at the entrance of the chamber
303 if (gMC->IsTrackEntering()) {
305 // Create TR only for electrons
306 Int_t iPdg = gMC->TrackPid();
307 if (TMath::Abs(iPdg) != kPdgElectron) return;
313 gMC->TrackMomentum(mom);
314 Float_t pTot = mom.Rho();
315 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
317 printf("AliTRDv1::CreateTRhit -- ");
318 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
322 // Loop through the TR photons
323 for (Int_t iTR = 0; iTR < nTR; iTR++) {
325 Float_t energyMeV = eTR[iTR] * 0.001;
326 Float_t energyeV = eTR[iTR] * 1000.0;
327 Float_t absLength = 0;
330 // Take the absorbtion in the entrance window into account
331 Double_t muMy = fTR->GetMuMy(energyMeV);
332 sigma = muMy * fFoilDensity;
333 absLength = gRandom->Exp(sigma);
334 if (absLength < AliTRDgeometry::MyThick()) continue;
336 // The absorbtion cross sections in the drift gas
338 // Gas-mixture (Xe/CO2)
339 Double_t muXe = fTR->GetMuXe(energyMeV);
340 Double_t muCO = fTR->GetMuCO(energyMeV);
341 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
344 // Gas-mixture (Xe/Isobutane)
345 Double_t muXe = fTR->GetMuXe(energyMeV);
346 Double_t muBu = fTR->GetMuBu(energyMeV);
347 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
350 // The distance after which the energy of the TR photon
352 absLength = gRandom->Exp(sigma);
353 if (absLength > AliTRDgeometry::DrThick()) continue;
355 // The position of the absorbtion
357 gMC->TrackPosition(pos);
358 posHit[0] = pos[0] + mom[0] / pTot * absLength;
359 posHit[1] = pos[1] + mom[1] / pTot * absLength;
360 posHit[2] = pos[2] + mom[2] / pTot * absLength;
363 Int_t q = ((Int_t) (energyeV / kWion));
365 // Add the hit to the array. TR photon hits are marked
366 // by negative charge
367 AddHit(gAlice->CurrentTrack(),det,posHit,-q,kTRUE);
375 //_____________________________________________________________________________
376 void AliTRDv1::Init()
379 // Initialise Transition Radiation Detector after geometry has been built.
384 if(fDebug) printf("%s: Slow simulator\n",ClassName());
387 printf(" Only plane %d is sensitive\n",fSensPlane);
388 if (fSensChamber >= 0)
389 printf(" Only chamber %d is sensitive\n",fSensChamber);
390 if (fSensSector >= 0) {
391 Int_t sens1 = fSensSector;
392 Int_t sens2 = fSensSector + fSensSectorRange;
393 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
394 * AliTRDgeometry::Nsect();
395 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
399 printf("%s: TR simulation on\n",ClassName());
401 printf("%s: TR simulation off\n",ClassName());
404 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
405 const Float_t kPoti = 12.1;
406 // Maximum energy (50 keV);
407 const Float_t kEend = 50000.0;
408 // Ermilova distribution for the delta-ray spectrum
409 Float_t poti = TMath::Log(kPoti);
410 Float_t eEnd = TMath::Log(kEend);
411 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
414 printf("%s: ",ClassName());
415 for (Int_t i = 0; i < 80; i++) printf("*");
421 //_____________________________________________________________________________
422 AliTRDsim *AliTRDv1::CreateTR()
425 // Enables the simulation of TR
428 fTR = new AliTRDsim();
433 //_____________________________________________________________________________
434 void AliTRDv1::SetSensPlane(Int_t iplane)
437 // Defines the hit-sensitive plane (0-5)
440 if ((iplane < 0) || (iplane > 5)) {
441 printf("Wrong input value: %d\n",iplane);
442 printf("Use standard setting\n");
453 //_____________________________________________________________________________
454 void AliTRDv1::SetSensChamber(Int_t ichamber)
457 // Defines the hit-sensitive chamber (0-4)
460 if ((ichamber < 0) || (ichamber > 4)) {
461 printf("Wrong input value: %d\n",ichamber);
462 printf("Use standard setting\n");
469 fSensChamber = ichamber;
473 //_____________________________________________________________________________
474 void AliTRDv1::SetSensSector(Int_t isector)
477 // Defines the hit-sensitive sector (0-17)
480 SetSensSector(isector,1);
484 //_____________________________________________________________________________
485 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
488 // Defines a range of hit-sensitive sectors. The range is defined by
489 // <isector> (0-17) as the starting point and <nsector> as the number
490 // of sectors to be included.
493 if ((isector < 0) || (isector > 17)) {
494 printf("Wrong input value <isector>: %d\n",isector);
495 printf("Use standard setting\n");
497 fSensSectorRange = 0;
502 if ((nsector < 1) || (nsector > 18)) {
503 printf("Wrong input value <nsector>: %d\n",nsector);
504 printf("Use standard setting\n");
506 fSensSectorRange = 0;
512 fSensSector = isector;
513 fSensSectorRange = nsector;
517 //_____________________________________________________________________________
518 void AliTRDv1::StepManager()
521 // Slow simulator. Every charged track produces electron cluster as hits
522 // along its path across the drift volume. The step size is set acording
523 // to Bethe-Bloch. The energy distribution of the delta electrons follows
524 // a spectrum taken from Ermilova et al.
541 Double_t betaGamma, pp;
544 Bool_t drRegion = kFALSE;
545 Bool_t amRegion = kFALSE;
548 TString cIdSensDr = "J";
549 TString cIdSensAm = "K";
550 Char_t cIdChamber[3];
553 TLorentzVector pos, mom;
555 const Int_t kNplan = AliTRDgeometry::Nplan();
556 const Int_t kNcham = AliTRDgeometry::Ncham();
557 const Int_t kNdetsec = kNplan * kNcham;
559 const Double_t kBig = 1.0E+12;
562 const Float_t kWion = 22.04;
563 // Maximum momentum for e+ e- g
564 const Float_t kPTotMaxEl = 0.002;
565 // Minimum energy for the step size adjustment
566 const Float_t kEkinMinStep = 1.0e-5;
567 // Plateau value of the energy-loss for electron in xenon
568 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
569 //const Double_t kPlateau = 1.70;
570 // the averaged value (26/3/99)
571 const Float_t kPlateau = 1.55;
572 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
573 const Float_t kPrim = 48.0;
574 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
575 const Float_t kPoti = 12.1;
578 const Int_t kPdgElectron = 11;
580 // Set the maximum step size to a very large number for all
581 // neutral particles and those outside the driftvolume
582 gMC->SetMaxStep(kBig);
584 // Use only charged tracks
585 if (( gMC->TrackCharge() ) &&
586 (!gMC->IsTrackStop() ) &&
587 (!gMC->IsTrackDisappeared())) {
589 // Inside a sensitive volume?
592 cIdCurrent = gMC->CurrentVolName();
593 if (cIdSensDr == cIdCurrent[1]) {
596 if (cIdSensAm == cIdCurrent[1]) {
599 if (drRegion || amRegion) {
601 // The hit coordinates and charge
602 gMC->TrackPosition(pos);
607 // The sector number (0 - 17)
608 // The numbering goes clockwise and starts at y = 0
609 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
614 sec = ((Int_t) (phi / 20));
616 // The plane and chamber number
617 cIdChamber[0] = cIdCurrent[2];
618 cIdChamber[1] = cIdCurrent[3];
619 Int_t idChamber = (atoi(cIdChamber) % kNdetsec);
620 cha = ((Int_t) idChamber / kNplan);
621 pla = ((Int_t) idChamber % kNplan);
623 // Check on selected volumes
624 Int_t addthishit = 1;
626 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
627 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
628 if (fSensSector >= 0) {
629 Int_t sens1 = fSensSector;
630 Int_t sens2 = fSensSector + fSensSectorRange;
631 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
632 * AliTRDgeometry::Nsect();
634 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
637 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
645 // The detector number
646 det = fGeometry->GetDetector(pla,cha,sec);
648 // Special hits and TR photons only in the drift region
651 // Create a track reference at the entrance and
652 // exit of each chamber that contain the
653 // momentum components of the particle
654 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
655 gMC->TrackMomentum(mom);
656 AddTrackReference(gAlice->CurrentTrack(),gMC);
659 // Create the hits from TR photons
660 if (fTR) CreateTRhit(det);
664 // Calculate the energy of the delta-electrons
665 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
666 eDelta = TMath::Max(eDelta,0.0);
668 // The number of secondary electrons created
669 qTot = ((Int_t) (eDelta / kWion) + 1);
671 // Create a new dEdx hit
673 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kTRUE);
676 AddHit(gAlice->CurrentTrack(),det,hits,qTot,kFALSE);
679 // Calculate the maximum step size for the next tracking step
680 // Produce only one hit if Ekin is below cutoff
681 aMass = gMC->TrackMass();
682 if ((gMC->Etot() - aMass) > kEkinMinStep) {
684 // The energy loss according to Bethe Bloch
685 iPdg = TMath::Abs(gMC->TrackPid());
686 if ( (iPdg != kPdgElectron) ||
687 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
688 gMC->TrackMomentum(mom);
690 betaGamma = pTot / aMass;
691 pp = kPrim * BetheBloch(betaGamma);
692 // Take charge > 1 into account
693 charge = gMC->TrackCharge();
694 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
696 // Electrons above 20 Mev/c are at the plateau
698 pp = kPrim * kPlateau;
703 gMC->GetRandom()->RndmArray(1, random);
704 while ((random[0] == 1.) || (random[0] == 0.));
705 stepSize = - TMath::Log(random[0]) / pp;
706 gMC->SetMaxStep(stepSize);
719 //_____________________________________________________________________________
720 Double_t AliTRDv1::BetheBloch(Double_t bg)
723 // Parametrization of the Bethe-Bloch-curve
724 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
727 // This parameters have been adjusted to averaged values from GEANT
728 const Double_t kP1 = 7.17960e-02;
729 const Double_t kP2 = 8.54196;
730 const Double_t kP3 = 1.38065e-06;
731 const Double_t kP4 = 5.30972;
732 const Double_t kP5 = 2.83798;
734 // This parameters have been adjusted to Xe-data found in:
735 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
736 //const Double_t kP1 = 0.76176E-1;
737 //const Double_t kP2 = 10.632;
738 //const Double_t kP3 = 3.17983E-6;
739 //const Double_t kP4 = 1.8631;
740 //const Double_t kP5 = 1.9479;
742 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
743 const Double_t kBgMin = 0.8;
744 const Double_t kBBMax = 6.83298;
745 //const Double_t kBgMin = 0.6;
746 //const Double_t kBBMax = 17.2809;
747 //const Double_t kBgMin = 0.4;
748 //const Double_t kBBMax = 82.0;
751 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
752 Double_t aa = TMath::Power(yy,kP4);
753 Double_t bb = TMath::Power((1./bg),kP5);
754 bb = TMath::Log(kP3 + bb);
755 return ((kP2 - aa - bb)*kP1 / aa);
763 //_____________________________________________________________________________
764 Double_t Ermilova(Double_t *x, Double_t *)
767 // Calculates the delta-ray energy distribution according to Ermilova.
768 // Logarithmic scale !
777 const Int_t kNv = 31;
779 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
780 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
781 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
782 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
783 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
784 , 9.4727, 9.9035,10.3735,10.5966,10.8198
787 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
788 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
789 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
790 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
791 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
792 , 0.04 , 0.023, 0.015, 0.011, 0.01
801 dpos = energy - vxe[pos2++];
805 if (pos2 > kNv) pos2 = kNv - 1;
808 // Differentiate between the sampling points
809 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);