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 1.29 2001/05/16 14:57:28 alibrary
19 New files for folders and Stack
21 Revision 1.28 2001/05/07 08:03:22 cblume
22 Generate also hits in the amplification region
24 Revision 1.27 2001/03/30 14:40:15 cblume
25 Update of the digitization parameter
27 Revision 1.26 2000/11/30 17:38:08 cblume
28 Changes to get in line with new STEER and EVGEN
30 Revision 1.25 2000/11/15 14:30:16 cblume
31 Fixed bug in calculating detector no. of extra hit
33 Revision 1.24 2000/11/10 14:58:36 cblume
34 Introduce additional hit with amplitude 0 at the chamber borders
36 Revision 1.23 2000/11/01 14:53:21 cblume
37 Merge with TRD-develop
39 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
42 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
45 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
46 Replace include files by forward declarations
48 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
49 Include TR photon generation and adapt to new AliTRDhit
51 Revision 1.22 2000/06/27 13:08:50 cblume
52 Changed to Copy(TObject &A) to appease the HP-compiler
54 Revision 1.21 2000/06/09 11:10:07 cblume
55 Compiler warnings and coding conventions, next round
57 Revision 1.20 2000/06/08 18:32:58 cblume
58 Make code compliant to coding conventions
60 Revision 1.19 2000/06/07 16:27:32 cblume
61 Try to remove compiler warnings on Sun and HP
63 Revision 1.18 2000/05/08 16:17:27 cblume
66 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
67 Made inline function non-virtual. Bug fix in setting sensitive chamber
69 Revision 1.17 2000/02/28 19:10:26 cblume
70 Include the new TRD classes
72 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
73 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
75 Revision 1.16 1999/11/05 22:50:28 fca
76 Do not use Atan, removed from ROOT too
78 Revision 1.15 1999/11/02 17:20:19 fca
79 initialise nbytes before using it
81 Revision 1.14 1999/11/02 17:15:54 fca
82 Correct ansi scoping not accepted by HP compilers
84 Revision 1.13 1999/11/02 17:14:51 fca
85 Correct ansi scoping not accepted by HP compilers
87 Revision 1.12 1999/11/02 16:35:56 fca
88 New version of TRD introduced
90 Revision 1.11 1999/11/01 20:41:51 fca
91 Added protections against using the wrong version of FRAME
93 Revision 1.10 1999/09/29 09:24:35 fca
94 Introduction of the Copyright and cvs Log
98 ///////////////////////////////////////////////////////////////////////////////
100 // Transition Radiation Detector version 1 -- slow simulator //
104 <img src="picts/AliTRDfullClass.gif">
109 ///////////////////////////////////////////////////////////////////////////////
117 #include <TLorentzVector.h>
121 #include "AliConst.h"
123 #include "AliTRDv1.h"
124 #include "AliTRDhit.h"
125 #include "AliTRDmatrix.h"
126 #include "AliTRDgeometry.h"
127 #include "AliTRDsim.h"
131 //_____________________________________________________________________________
132 AliTRDv1::AliTRDv1():AliTRD()
135 // Default constructor
149 fSensSectorRange = 0;
156 //_____________________________________________________________________________
157 AliTRDv1::AliTRDv1(const char *name, const char *title)
161 // Standard constructor for Transition Radiation Detector version 1
175 fSensSectorRange = 0;
180 SetBufferSize(128000);
184 //_____________________________________________________________________________
185 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
191 ((AliTRDv1 &) trd).Copy(*this);
195 //_____________________________________________________________________________
196 AliTRDv1::~AliTRDv1()
199 // AliTRDv1 destructor
202 if (fDeltaE) delete fDeltaE;
207 //_____________________________________________________________________________
208 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
211 // Assignment operator
214 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
219 //_____________________________________________________________________________
220 void AliTRDv1::Copy(TObject &trd)
226 ((AliTRDv1 &) trd).fIdSensDr = fIdSensDr;
227 ((AliTRDv1 &) trd).fIdSensAm = fIdSensAm;
229 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
230 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
231 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
233 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
234 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
235 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
236 ((AliTRDv1 &) trd).fSensSector = fSensSector;
237 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
239 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
240 fTR->Copy(*((AliTRDv1 &) trd).fTR);
244 //_____________________________________________________________________________
245 void AliTRDv1::CreateGeometry()
248 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
249 // This version covers the full azimuth.
252 // Check that FRAME is there otherwise we have no place where to put the TRD
253 AliModule* frame = gAlice->GetModule("FRAME");
256 // Define the chambers
257 AliTRD::CreateGeometry();
261 //_____________________________________________________________________________
262 void AliTRDv1::CreateMaterials()
265 // Create materials for the Transition Radiation Detector version 1
268 AliTRD::CreateMaterials();
272 //_____________________________________________________________________________
273 void AliTRDv1::CreateTRhit(Int_t det)
276 // Creates an electron cluster from a TR photon.
277 // The photon is assumed to be created a the end of the radiator. The
278 // distance after which it deposits its energy takes into account the
279 // absorbtion of the entrance window and of the gas mixture in drift
284 const Int_t kPdgElectron = 11;
287 const Float_t kWion = 22.04;
289 // Maximum number of TR photons per track
290 const Int_t kNTR = 50;
292 TLorentzVector mom, pos;
293 TClonesArray &lhits = *fHits;
295 // Create TR at the entrance of the chamber
296 if (gMC->IsTrackEntering()) {
298 // Create TR only for electrons
299 Int_t iPdg = gMC->TrackPid();
300 if (TMath::Abs(iPdg) != kPdgElectron) return;
306 gMC->TrackMomentum(mom);
307 Float_t pTot = mom.Rho();
308 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
310 printf("AliTRDv1::CreateTRhit -- ");
311 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
315 // Loop through the TR photons
316 for (Int_t iTR = 0; iTR < nTR; iTR++) {
318 Float_t energyMeV = eTR[iTR] * 0.001;
319 Float_t energyeV = eTR[iTR] * 1000.0;
320 Float_t absLength = 0;
323 // Take the absorbtion in the entrance window into account
324 Double_t muMy = fTR->GetMuMy(energyMeV);
325 sigma = muMy * fFoilDensity;
326 absLength = gRandom->Exp(sigma);
327 if (absLength < AliTRDgeometry::MyThick()) continue;
329 // The absorbtion cross sections in the drift gas
331 // Gas-mixture (Xe/CO2)
332 Double_t muXe = fTR->GetMuXe(energyMeV);
333 Double_t muCO = fTR->GetMuCO(energyMeV);
334 sigma = (0.85 * muXe + 0.15 * muCO) * fGasDensity;
337 // Gas-mixture (Xe/Isobutane)
338 Double_t muXe = fTR->GetMuXe(energyMeV);
339 Double_t muBu = fTR->GetMuBu(energyMeV);
340 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
343 // The distance after which the energy of the TR photon
345 absLength = gRandom->Exp(sigma);
346 if (absLength > AliTRDgeometry::DrThick()) continue;
348 // The position of the absorbtion
350 gMC->TrackPosition(pos);
351 posHit[0] = pos[0] + mom[0] / pTot * absLength;
352 posHit[1] = pos[1] + mom[1] / pTot * absLength;
353 posHit[2] = pos[2] + mom[2] / pTot * absLength;
356 Int_t q = ((Int_t) (energyeV / kWion));
358 // Add the hit to the array. TR photon hits are marked
359 // by negative charge
360 AliTRDhit *hit = new(lhits[fNhits++]) AliTRDhit(fIshunt
361 ,gAlice->CurrentTrack()
371 //_____________________________________________________________________________
372 void AliTRDv1::Init()
375 // Initialise Transition Radiation Detector after geometry has been built.
380 if(fDebug) printf("%s: Slow simulator\n",ClassName());
383 printf(" Only plane %d is sensitive\n",fSensPlane);
384 if (fSensChamber >= 0)
385 printf(" Only chamber %d is sensitive\n",fSensChamber);
386 if (fSensSector >= 0) {
387 Int_t sens1 = fSensSector;
388 Int_t sens2 = fSensSector + fSensSectorRange;
389 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
390 * AliTRDgeometry::Nsect();
391 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
395 printf("%s: TR simulation on\n",ClassName());
397 printf("%s: TR simulation off\n",ClassName());
400 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
401 const Float_t kPoti = 12.1;
402 // Maximum energy (50 keV);
403 const Float_t kEend = 50000.0;
404 // Ermilova distribution for the delta-ray spectrum
405 Float_t poti = TMath::Log(kPoti);
406 Float_t eEnd = TMath::Log(kEend);
407 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
409 // Identifier of the sensitive volume (drift region)
410 fIdSensDr = gMC->VolId("UL05");
411 // Identifier of the sensitive volume (amplification region)
412 fIdSensAm = gMC->VolId("UL06");
414 // Identifier of the TRD-driftchambers
415 fIdChamber1 = gMC->VolId("UCIO");
416 fIdChamber2 = gMC->VolId("UCIM");
417 fIdChamber3 = gMC->VolId("UCII");
420 printf("%s: ",ClassName());
421 for (Int_t i = 0; i < 80; i++) printf("*");
427 //_____________________________________________________________________________
428 AliTRDsim *AliTRDv1::CreateTR()
431 // Enables the simulation of TR
434 fTR = new AliTRDsim();
439 //_____________________________________________________________________________
440 void AliTRDv1::SetSensPlane(Int_t iplane)
443 // Defines the hit-sensitive plane (0-5)
446 if ((iplane < 0) || (iplane > 5)) {
447 printf("Wrong input value: %d\n",iplane);
448 printf("Use standard setting\n");
459 //_____________________________________________________________________________
460 void AliTRDv1::SetSensChamber(Int_t ichamber)
463 // Defines the hit-sensitive chamber (0-4)
466 if ((ichamber < 0) || (ichamber > 4)) {
467 printf("Wrong input value: %d\n",ichamber);
468 printf("Use standard setting\n");
475 fSensChamber = ichamber;
479 //_____________________________________________________________________________
480 void AliTRDv1::SetSensSector(Int_t isector)
483 // Defines the hit-sensitive sector (0-17)
486 SetSensSector(isector,1);
490 //_____________________________________________________________________________
491 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
494 // Defines a range of hit-sensitive sectors. The range is defined by
495 // <isector> (0-17) as the starting point and <nsector> as the number
496 // of sectors to be included.
499 if ((isector < 0) || (isector > 17)) {
500 printf("Wrong input value <isector>: %d\n",isector);
501 printf("Use standard setting\n");
503 fSensSectorRange = 0;
508 if ((nsector < 1) || (nsector > 18)) {
509 printf("Wrong input value <nsector>: %d\n",nsector);
510 printf("Use standard setting\n");
512 fSensSectorRange = 0;
518 fSensSector = isector;
519 fSensSectorRange = nsector;
523 //_____________________________________________________________________________
524 void AliTRDv1::StepManager()
527 // Slow simulator. Every charged track produces electron cluster as hits
528 // along its path across the drift volume. The step size is set acording
529 // to Bethe-Bloch. The energy distribution of the delta electrons follows
530 // a spectrum taken from Ermilova et al.
533 Int_t iIdSens, icSens;
534 Int_t iIdChamber, icChamber;
550 Double_t betaGamma, pp;
553 TLorentzVector pos, mom;
554 TClonesArray &lhits = *fHits;
556 const Double_t kBig = 1.0E+12;
559 const Float_t kWion = 22.04;
560 // Maximum momentum for e+ e- g
561 const Float_t kPTotMaxEl = 0.002;
562 // Minimum energy for the step size adjustment
563 const Float_t kEkinMinStep = 1.0e-5;
564 // Plateau value of the energy-loss for electron in xenon
565 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
566 //const Double_t kPlateau = 1.70;
567 // the averaged value (26/3/99)
568 const Float_t kPlateau = 1.55;
569 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
570 const Float_t kPrim = 48.0;
571 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
572 const Float_t kPoti = 12.1;
575 const Int_t kPdgElectron = 11;
577 // Set the maximum step size to a very large number for all
578 // neutral particles and those outside the driftvolume
579 gMC->SetMaxStep(kBig);
581 // Use only charged tracks
582 if (( gMC->TrackCharge() ) &&
583 (!gMC->IsTrackStop() ) &&
584 (!gMC->IsTrackDisappeared())) {
586 // Inside a sensitive volume?
587 iIdSens = gMC->CurrentVolID(icSens);
588 if ((iIdSens == fIdSensDr) ||
589 (iIdSens == fIdSensAm)) {
591 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
593 // The hit coordinates and charge
594 gMC->TrackPosition(pos);
599 // The sector number (0 - 17)
600 // The numbering goes clockwise and starts at y = 0
601 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
606 sec = ((Int_t) (phi / 20));
608 // The chamber number
614 if (iIdChamber == fIdChamber1)
615 cha = (hits[2] < 0 ? 0 : 4);
616 else if (iIdChamber == fIdChamber2)
617 cha = (hits[2] < 0 ? 1 : 3);
618 else if (iIdChamber == fIdChamber3)
622 // The numbering starts at the innermost plane
623 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
625 // Check on selected volumes
626 Int_t addthishit = 1;
628 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
629 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
630 if (fSensSector >= 0) {
631 Int_t sens1 = fSensSector;
632 Int_t sens2 = fSensSector + fSensSectorRange;
633 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
634 * AliTRDgeometry::Nsect();
636 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
639 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
647 // The detector number
648 det = fGeometry->GetDetector(pla,cha,sec);
650 // Special hits and TR photons only in the drift region
651 if (iIdSens == fIdSensDr) {
653 // Create some special hits with amplitude 0 at the entrance and
654 // exit of each chamber that contain the momentum components of the particle
655 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
656 gMC->TrackMomentum(mom);
660 AliTRDhit *hitTest = new(lhits[fNhits++]) AliTRDhit(fIshunt
661 ,gAlice->CurrentTrack()
666 // Create the hits from TR photons
667 if (fTR) CreateTRhit(det);
671 // Calculate the energy of the delta-electrons
672 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
673 eDelta = TMath::Max(eDelta,0.0);
675 // The number of secondary electrons created
676 qTot = ((Int_t) (eDelta / kWion) + 1);
678 // Create a new dEdx hit
679 AliTRDhit *hit = new(lhits[fNhits++]) AliTRDhit(fIshunt
680 ,gAlice->CurrentTrack()
682 if (iIdSens == fIdSensDr) {
686 hit->SetAmplification();
689 // Calculate the maximum step size for the next tracking step
690 // Produce only one hit if Ekin is below cutoff
691 aMass = gMC->TrackMass();
692 if ((gMC->Etot() - aMass) > kEkinMinStep) {
694 // The energy loss according to Bethe Bloch
695 iPdg = TMath::Abs(gMC->TrackPid());
696 if ( (iPdg != kPdgElectron) ||
697 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
698 gMC->TrackMomentum(mom);
700 betaGamma = pTot / aMass;
701 pp = kPrim * BetheBloch(betaGamma);
702 // Take charge > 1 into account
703 charge = gMC->TrackCharge();
704 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
706 // Electrons above 20 Mev/c are at the plateau
708 pp = kPrim * kPlateau;
714 while ((random[0] == 1.) || (random[0] == 0.));
715 stepSize = - TMath::Log(random[0]) / pp;
716 gMC->SetMaxStep(stepSize);
729 //_____________________________________________________________________________
730 Double_t AliTRDv1::BetheBloch(Double_t bg)
733 // Parametrization of the Bethe-Bloch-curve
734 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
737 // This parameters have been adjusted to averaged values from GEANT
738 const Double_t kP1 = 7.17960e-02;
739 const Double_t kP2 = 8.54196;
740 const Double_t kP3 = 1.38065e-06;
741 const Double_t kP4 = 5.30972;
742 const Double_t kP5 = 2.83798;
744 // This parameters have been adjusted to Xe-data found in:
745 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
746 //const Double_t kP1 = 0.76176E-1;
747 //const Double_t kP2 = 10.632;
748 //const Double_t kP3 = 3.17983E-6;
749 //const Double_t kP4 = 1.8631;
750 //const Double_t kP5 = 1.9479;
752 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
753 const Double_t kBgMin = 0.8;
754 const Double_t kBBMax = 6.83298;
755 //const Double_t kBgMin = 0.6;
756 //const Double_t kBBMax = 17.2809;
757 //const Double_t kBgMin = 0.4;
758 //const Double_t kBBMax = 82.0;
761 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
762 Double_t aa = TMath::Power(yy,kP4);
763 Double_t bb = TMath::Power((1./bg),kP5);
764 bb = TMath::Log(kP3 + bb);
765 return ((kP2 - aa - bb)*kP1 / aa);
773 //_____________________________________________________________________________
774 Double_t Ermilova(Double_t *x, Double_t *)
777 // Calculates the delta-ray energy distribution according to Ermilova.
778 // Logarithmic scale !
787 const Int_t kNv = 31;
789 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
790 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
791 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
792 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
793 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
794 , 9.4727, 9.9035,10.3735,10.5966,10.8198
797 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
798 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
799 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
800 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
801 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
802 , 0.04 , 0.023, 0.015, 0.011, 0.01
811 dpos = energy - vxe[pos2++];
815 if (pos2 > kNv) pos2 = kNv - 1;
818 // Differentiate between the sampling points
819 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);