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 1.23 2000/11/01 14:53:21 cblume
19 Merge with TRD-develop
21 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
24 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
27 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
28 Replace include files by forward declarations
30 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
31 Include TR photon generation and adapt to new AliTRDhit
33 Revision 1.22 2000/06/27 13:08:50 cblume
34 Changed to Copy(TObject &A) to appease the HP-compiler
36 Revision 1.21 2000/06/09 11:10:07 cblume
37 Compiler warnings and coding conventions, next round
39 Revision 1.20 2000/06/08 18:32:58 cblume
40 Make code compliant to coding conventions
42 Revision 1.19 2000/06/07 16:27:32 cblume
43 Try to remove compiler warnings on Sun and HP
45 Revision 1.18 2000/05/08 16:17:27 cblume
48 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
49 Made inline function non-virtual. Bug fix in setting sensitive chamber
51 Revision 1.17 2000/02/28 19:10:26 cblume
52 Include the new TRD classes
54 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
55 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
57 Revision 1.16 1999/11/05 22:50:28 fca
58 Do not use Atan, removed from ROOT too
60 Revision 1.15 1999/11/02 17:20:19 fca
61 initialise nbytes before using it
63 Revision 1.14 1999/11/02 17:15:54 fca
64 Correct ansi scoping not accepted by HP compilers
66 Revision 1.13 1999/11/02 17:14:51 fca
67 Correct ansi scoping not accepted by HP compilers
69 Revision 1.12 1999/11/02 16:35:56 fca
70 New version of TRD introduced
72 Revision 1.11 1999/11/01 20:41:51 fca
73 Added protections against using the wrong version of FRAME
75 Revision 1.10 1999/09/29 09:24:35 fca
76 Introduction of the Copyright and cvs Log
80 ///////////////////////////////////////////////////////////////////////////////
82 // Transition Radiation Detector version 1 -- slow simulator //
86 <img src="picts/AliTRDfullClass.gif">
91 ///////////////////////////////////////////////////////////////////////////////
102 #include "AliConst.h"
104 #include "AliTRDv1.h"
105 #include "AliTRDhit.h"
106 #include "AliTRDmatrix.h"
107 #include "AliTRDgeometry.h"
108 #include "AliTRDsim.h"
112 //_____________________________________________________________________________
113 AliTRDv1::AliTRDv1():AliTRD()
116 // Default constructor
129 fSensSectorRange = 0;
136 //_____________________________________________________________________________
137 AliTRDv1::AliTRDv1(const char *name, const char *title)
141 // Standard constructor for Transition Radiation Detector version 1
154 fSensSectorRange = 0;
159 SetBufferSize(128000);
163 //_____________________________________________________________________________
164 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
170 ((AliTRDv1 &) trd).Copy(*this);
174 //_____________________________________________________________________________
175 AliTRDv1::~AliTRDv1()
178 // AliTRDv1 destructor
181 if (fDeltaE) delete fDeltaE;
186 //_____________________________________________________________________________
187 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
190 // Assignment operator
193 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
198 //_____________________________________________________________________________
199 void AliTRDv1::Copy(TObject &trd)
205 ((AliTRDv1 &) trd).fIdSens = fIdSens;
207 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
208 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
209 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
211 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
212 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
213 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
214 ((AliTRDv1 &) trd).fSensSector = fSensSector;
215 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
217 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
218 fTR->Copy(*((AliTRDv1 &) trd).fTR);
222 //_____________________________________________________________________________
223 void AliTRDv1::CreateGeometry()
226 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
227 // This version covers the full azimuth.
230 // Check that FRAME is there otherwise we have no place where to put the TRD
231 AliModule* frame = gAlice->GetModule("FRAME");
234 // Define the chambers
235 AliTRD::CreateGeometry();
239 //_____________________________________________________________________________
240 void AliTRDv1::CreateMaterials()
243 // Create materials for the Transition Radiation Detector version 1
246 AliTRD::CreateMaterials();
250 //_____________________________________________________________________________
251 void AliTRDv1::CreateTRhit(Int_t det)
254 // Creates an electron cluster from a TR photon.
255 // The photon is assumed to be created a the end of the radiator. The
256 // distance after which it deposits its energy takes into account the
257 // absorbtion of the entrance window and of the gas mixture in drift
262 const Int_t kPdgElectron = 11;
265 const Float_t kWion = 22.04;
267 // Maximum number of TR photons per track
268 const Int_t kNTR = 50;
270 TLorentzVector mom, pos;
271 TClonesArray &lhits = *fHits;
273 // Create TR only for electrons
274 Int_t iPdg = gMC->TrackPid();
275 if (TMath::Abs(iPdg) != kPdgElectron) return;
277 // Create TR at the entrance of the chamber
278 if (gMC->IsTrackEntering()) {
284 gMC->TrackMomentum(mom);
285 Float_t pTot = mom.Rho();
286 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
288 printf("AliTRDv1::CreateTRhit -- ");
289 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
293 // Loop through the TR photons
294 for (Int_t iTR = 0; iTR < nTR; iTR++) {
296 Float_t energyMeV = eTR[iTR] * 0.001;
297 Float_t energyeV = eTR[iTR] * 1000.0;
298 Float_t absLength = 0;
301 // Take the absorbtion in the entrance window into account
302 Double_t muMy = fTR->GetMuMy(energyMeV);
303 sigma = muMy * fFoilDensity;
304 absLength = gRandom->Exp(sigma);
305 if (absLength < AliTRDgeometry::MyThick()) continue;
307 // The absorbtion cross sections in the drift gas
309 // Gas-mixture (Xe/CO2)
310 Double_t muXe = fTR->GetMuXe(energyMeV);
311 Double_t muCO = fTR->GetMuCO(energyMeV);
312 sigma = (0.90 * muXe + 0.10 * muCO) * fGasDensity;
315 // Gas-mixture (Xe/Isobutane)
316 Double_t muXe = fTR->GetMuXe(energyMeV);
317 Double_t muBu = fTR->GetMuBu(energyMeV);
318 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
321 // The distance after which the energy of the TR photon
323 absLength = gRandom->Exp(sigma);
324 if (absLength > AliTRDgeometry::DrThick()) continue;
326 // The position of the absorbtion
328 gMC->TrackPosition(pos);
329 posHit[0] = pos[0] + mom[0] / pTot * absLength;
330 posHit[1] = pos[1] + mom[1] / pTot * absLength;
331 posHit[2] = pos[2] + mom[2] / pTot * absLength;
334 Int_t q = ((Int_t) (energyeV / kWion));
336 // Add the hit to the array. TR photon hits are marked
337 // by negative charge
338 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack()
347 //_____________________________________________________________________________
348 void AliTRDv1::Init()
351 // Initialise Transition Radiation Detector after geometry has been built.
356 printf(" Slow simulator\n\n");
359 printf(" Only plane %d is sensitive\n",fSensPlane);
360 if (fSensChamber >= 0)
361 printf(" Only chamber %d is sensitive\n",fSensChamber);
362 if (fSensSector >= 0) {
363 Int_t sens1 = fSensSector;
364 Int_t sens2 = fSensSector + fSensSectorRange;
365 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
366 * AliTRDgeometry::Nsect();
367 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
371 printf(" TR simulation on\n");
373 printf(" TR simulation off\n");
376 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
377 const Float_t kPoti = 12.1;
378 // Maximum energy (50 keV);
379 const Float_t kEend = 50000.0;
380 // Ermilova distribution for the delta-ray spectrum
381 Float_t poti = TMath::Log(kPoti);
382 Float_t eEnd = TMath::Log(kEend);
383 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
385 // Identifier of the sensitive volume (drift region)
386 fIdSens = gMC->VolId("UL05");
388 // Identifier of the TRD-driftchambers
389 fIdChamber1 = gMC->VolId("UCIO");
390 fIdChamber2 = gMC->VolId("UCIM");
391 fIdChamber3 = gMC->VolId("UCII");
393 for (Int_t i = 0; i < 80; i++) printf("*");
398 //_____________________________________________________________________________
399 AliTRDsim *AliTRDv1::CreateTR()
402 // Enables the simulation of TR
405 fTR = new AliTRDsim();
410 //_____________________________________________________________________________
411 void AliTRDv1::SetSensPlane(Int_t iplane)
414 // Defines the hit-sensitive plane (0-5)
417 if ((iplane < 0) || (iplane > 5)) {
418 printf("Wrong input value: %d\n",iplane);
419 printf("Use standard setting\n");
430 //_____________________________________________________________________________
431 void AliTRDv1::SetSensChamber(Int_t ichamber)
434 // Defines the hit-sensitive chamber (0-4)
437 if ((ichamber < 0) || (ichamber > 4)) {
438 printf("Wrong input value: %d\n",ichamber);
439 printf("Use standard setting\n");
446 fSensChamber = ichamber;
450 //_____________________________________________________________________________
451 void AliTRDv1::SetSensSector(Int_t isector)
454 // Defines the hit-sensitive sector (0-17)
457 SetSensSector(isector,1);
461 //_____________________________________________________________________________
462 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
465 // Defines a range of hit-sensitive sectors. The range is defined by
466 // <isector> (0-17) as the starting point and <nsector> as the number
467 // of sectors to be included.
470 if ((isector < 0) || (isector > 17)) {
471 printf("Wrong input value <isector>: %d\n",isector);
472 printf("Use standard setting\n");
474 fSensSectorRange = 0;
479 if ((nsector < 1) || (nsector > 18)) {
480 printf("Wrong input value <nsector>: %d\n",nsector);
481 printf("Use standard setting\n");
483 fSensSectorRange = 0;
489 fSensSector = isector;
490 fSensSectorRange = nsector;
494 //_____________________________________________________________________________
495 void AliTRDv1::StepManager()
498 // Slow simulator. Every charged track produces electron cluster as hits
499 // along its path across the drift volume. The step size is set acording
500 // to Bethe-Bloch. The energy distribution of the delta electrons follows
501 // a spectrum taken from Ermilova et al.
504 Int_t iIdSens, icSens;
505 Int_t iIdSpace, icSpace;
506 Int_t iIdChamber, icChamber;
521 Double_t betaGamma, pp;
523 TLorentzVector pos, mom;
524 TClonesArray &lhits = *fHits;
526 const Double_t kBig = 1.0E+12;
529 const Float_t kWion = 22.04;
530 // Maximum energy for e+ e- g for the step-size calculation
531 const Float_t kPTotMax = 0.002;
532 // Plateau value of the energy-loss for electron in xenon
533 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
534 //const Double_t kPlateau = 1.70;
535 // the averaged value (26/3/99)
536 const Float_t kPlateau = 1.55;
537 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
538 const Float_t kPrim = 48.0;
539 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
540 const Float_t kPoti = 12.1;
543 const Int_t kPdgElectron = 11;
545 // Set the maximum step size to a very large number for all
546 // neutral particles and those outside the driftvolume
547 gMC->SetMaxStep(kBig);
549 // Create some special hits with amplitude 0 at the entrance and
550 // exit of each chamber that contain the momentum components of the particle
551 if (gMC->TrackCharge() &&
552 (gMC->IsTrackEntering() || gMC->IsTrackExiting())) {
554 // Inside a sensitive volume?
555 iIdSens = gMC->CurrentVolID(icSens);
556 if (iIdSens == fIdSens) {
558 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
559 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
561 // The hit coordinates
562 gMC->TrackPosition(pos);
564 // The track momentum
565 gMC->TrackMomentum(mom);
570 // The sector number (0 - 17)
571 // The numbering goes clockwise and starts at y = 0
572 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
577 sec = ((Int_t) (phi / 20));
579 // The chamber number
585 if (iIdChamber == fIdChamber1)
586 cha = (hits[2] < 0 ? 0 : 4);
587 else if (iIdChamber == fIdChamber2)
588 cha = (hits[2] < 0 ? 1 : 3);
589 else if (iIdChamber == fIdChamber3)
593 // The numbering starts at the innermost plane
594 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
596 // Check on selected volumes
597 Int_t addthishit = 1;
599 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
600 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
601 if (fSensSector >= 0) {
602 Int_t sens1 = fSensSector;
603 Int_t sens2 = fSensSector + fSensSectorRange;
604 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
605 * AliTRDgeometry::Nsect();
607 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
610 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
617 det = fGeometry->GetDetector(pla,cha,sec);
618 new(lhits[fNhits++]) AliTRDhit(fIshunt
619 ,gAlice->CurrentTrack()
629 // Use only charged tracks
630 if (( gMC->TrackCharge() ) &&
631 (!gMC->IsTrackStop() ) &&
632 (!gMC->IsTrackDisappeared())) {
634 // Inside a sensitive volume?
635 iIdSens = gMC->CurrentVolID(icSens);
636 if (iIdSens == fIdSens) {
638 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
639 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
641 // Calculate the energy of the delta-electrons
642 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
643 eDelta = TMath::Max(eDelta,0.0);
645 // The number of secondary electrons created
646 qTot = ((Int_t) (eDelta / kWion) + 1);
648 // The hit coordinates and charge
649 gMC->TrackPosition(pos);
654 // The sector number (0 - 17)
655 // The numbering goes clockwise and starts at y = 0
656 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
661 sec = ((Int_t) (phi / 20));
663 // The chamber number
669 if (iIdChamber == fIdChamber1)
670 cha = (hits[2] < 0 ? 0 : 4);
671 else if (iIdChamber == fIdChamber2)
672 cha = (hits[2] < 0 ? 1 : 3);
673 else if (iIdChamber == fIdChamber3)
677 // The numbering starts at the innermost plane
678 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
680 // Check on selected volumes
681 Int_t addthishit = 1;
683 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
684 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
685 if (fSensSector >= 0) {
686 Int_t sens1 = fSensSector;
687 Int_t sens2 = fSensSector + fSensSectorRange;
688 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
689 * AliTRDgeometry::Nsect();
691 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
694 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
702 det = fGeometry->GetDetector(pla,cha,sec);
704 // Create the electron cluster from TR photons
705 if (fTR) CreateTRhit(det);
707 new(lhits[fNhits++]) AliTRDhit(fIshunt
708 ,gAlice->CurrentTrack()
713 // The energy loss according to Bethe Bloch
714 gMC->TrackMomentum(mom);
716 iPdg = TMath::Abs(gMC->TrackPid());
717 if ( (iPdg != kPdgElectron) ||
718 ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
719 aMass = gMC->TrackMass();
720 betaGamma = pTot / aMass;
721 pp = kPrim * BetheBloch(betaGamma);
722 // Take charge > 1 into account
723 charge = gMC->TrackCharge();
724 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
726 // Electrons above 20 Mev/c are at the plateau
728 pp = kPrim * kPlateau;
731 // Calculate the maximum step size for the next tracking step
735 while ((random[0] == 1.) || (random[0] == 0.));
736 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
741 // set step size to maximal value
742 gMC->SetMaxStep(kBig);
751 //_____________________________________________________________________________
752 Double_t AliTRDv1::BetheBloch(Double_t bg)
755 // Parametrization of the Bethe-Bloch-curve
756 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
759 // This parameters have been adjusted to averaged values from GEANT
760 const Double_t kP1 = 7.17960e-02;
761 const Double_t kP2 = 8.54196;
762 const Double_t kP3 = 1.38065e-06;
763 const Double_t kP4 = 5.30972;
764 const Double_t kP5 = 2.83798;
766 // This parameters have been adjusted to Xe-data found in:
767 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
768 //const Double_t kP1 = 0.76176E-1;
769 //const Double_t kP2 = 10.632;
770 //const Double_t kP3 = 3.17983E-6;
771 //const Double_t kP4 = 1.8631;
772 //const Double_t kP5 = 1.9479;
775 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
776 Double_t aa = TMath::Power(yy,kP4);
777 Double_t bb = TMath::Power((1./bg),kP5);
778 bb = TMath::Log(kP3 + bb);
779 return ((kP2 - aa - bb)*kP1 / aa);
786 //_____________________________________________________________________________
787 Double_t Ermilova(Double_t *x, Double_t *)
790 // Calculates the delta-ray energy distribution according to Ermilova.
791 // Logarithmic scale !
800 const Int_t kNv = 31;
802 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
803 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
804 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
805 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
806 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
807 , 9.4727, 9.9035,10.3735,10.5966,10.8198
810 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
811 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
812 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
813 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
814 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
815 , 0.04 , 0.023, 0.015, 0.011, 0.01
824 dpos = energy - vxe[pos2++];
828 if (pos2 > kNv) pos2 = kNv;
831 // Differentiate between the sampling points
832 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);