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 1.17.2.5 2000/10/15 23:40:01 cblume
21 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
24 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
25 Replace include files by forward declarations
27 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
28 Include TR photon generation and adapt to new AliTRDhit
30 Revision 1.22 2000/06/27 13:08:50 cblume
31 Changed to Copy(TObject &A) to appease the HP-compiler
33 Revision 1.21 2000/06/09 11:10:07 cblume
34 Compiler warnings and coding conventions, next round
36 Revision 1.20 2000/06/08 18:32:58 cblume
37 Make code compliant to coding conventions
39 Revision 1.19 2000/06/07 16:27:32 cblume
40 Try to remove compiler warnings on Sun and HP
42 Revision 1.18 2000/05/08 16:17:27 cblume
45 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
46 Made inline function non-virtual. Bug fix in setting sensitive chamber
48 Revision 1.17 2000/02/28 19:10:26 cblume
49 Include the new TRD classes
51 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
52 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
54 Revision 1.16 1999/11/05 22:50:28 fca
55 Do not use Atan, removed from ROOT too
57 Revision 1.15 1999/11/02 17:20:19 fca
58 initialise nbytes before using it
60 Revision 1.14 1999/11/02 17:15:54 fca
61 Correct ansi scoping not accepted by HP compilers
63 Revision 1.13 1999/11/02 17:14:51 fca
64 Correct ansi scoping not accepted by HP compilers
66 Revision 1.12 1999/11/02 16:35:56 fca
67 New version of TRD introduced
69 Revision 1.11 1999/11/01 20:41:51 fca
70 Added protections against using the wrong version of FRAME
72 Revision 1.10 1999/09/29 09:24:35 fca
73 Introduction of the Copyright and cvs Log
77 ///////////////////////////////////////////////////////////////////////////////
79 // Transition Radiation Detector version 2 -- slow simulator //
83 <img src="picts/AliTRDfullClass.gif">
88 ///////////////////////////////////////////////////////////////////////////////
100 #include "AliTRDhit.h"
101 #include "AliTRDmatrix.h"
102 #include "AliTRDgeometry.h"
103 #include "AliTRDsim.h"
107 //_____________________________________________________________________________
108 AliTRDv1::AliTRDv1():AliTRD()
111 // Default constructor
124 fSensSectorRange = 0;
131 //_____________________________________________________________________________
132 AliTRDv1::AliTRDv1(const char *name, const char *title)
136 // Standard constructor for Transition Radiation Detector version 1
149 fSensSectorRange = 0;
154 SetBufferSize(128000);
158 //_____________________________________________________________________________
159 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
165 ((AliTRDv1 &) trd).Copy(*this);
169 //_____________________________________________________________________________
170 AliTRDv1::~AliTRDv1()
173 // AliTRDv1 destructor
176 if (fDeltaE) delete fDeltaE;
181 //_____________________________________________________________________________
182 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
185 // Assignment operator
188 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
193 //_____________________________________________________________________________
194 void AliTRDv1::Copy(TObject &trd)
200 ((AliTRDv1 &) trd).fIdSens = fIdSens;
202 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
203 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
204 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
206 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
207 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
208 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
209 ((AliTRDv1 &) trd).fSensSector = fSensSector;
210 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
212 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
213 fTR->Copy(*((AliTRDv1 &) trd).fTR);
217 //_____________________________________________________________________________
218 void AliTRDv1::CreateGeometry()
221 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
222 // This version covers the full azimuth.
225 // Check that FRAME is there otherwise we have no place where to put the TRD
226 AliModule* frame = gAlice->GetModule("FRAME");
229 // Define the chambers
230 AliTRD::CreateGeometry();
234 //_____________________________________________________________________________
235 void AliTRDv1::CreateMaterials()
238 // Create materials for the Transition Radiation Detector version 1
241 AliTRD::CreateMaterials();
245 //_____________________________________________________________________________
246 void AliTRDv1::CreateTRhit(Int_t det)
249 // Creates an electron cluster from a TR photon.
250 // The photon is assumed to be created a the end of the radiator. The
251 // distance after which it deposits its energy takes into account the
252 // absorbtion of the entrance window and of the gas mixture in drift
257 const Int_t kPdgElectron = 11;
260 const Float_t kWion = 22.04;
262 // Maximum number of TR photons per track
263 const Int_t kNTR = 50;
265 TLorentzVector mom, pos;
266 TClonesArray &lhits = *fHits;
268 // Create TR only for electrons
269 Int_t iPdg = gMC->TrackPid();
270 if (TMath::Abs(iPdg) != kPdgElectron) return;
272 // Create TR at the entrance of the chamber
273 if (gMC->IsTrackEntering()) {
279 gMC->TrackMomentum(mom);
280 Float_t pTot = mom.Rho();
281 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
283 printf("AliTRDv1::CreateTRhit -- ");
284 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
288 // Loop through the TR photons
289 for (Int_t iTR = 0; iTR < nTR; iTR++) {
291 Float_t energyMeV = eTR[iTR] * 0.001;
292 Float_t energyeV = eTR[iTR] * 1000.0;
293 Float_t absLength = 0;
296 // Take the absorbtion in the entrance window into account
297 Double_t muMy = fTR->GetMuMy(energyMeV);
298 sigma = muMy * fFoilDensity;
299 absLength = gRandom->Exp(sigma);
300 if (absLength < AliTRDgeometry::MyThick()) continue;
302 // The absorbtion cross sections in the drift gas
304 // Gas-mixture (Xe/CO2)
305 Double_t muXe = fTR->GetMuXe(energyMeV);
306 Double_t muCO = fTR->GetMuCO(energyMeV);
307 sigma = (0.90 * muXe + 0.10 * muCO) * fGasDensity;
310 // Gas-mixture (Xe/Isobutane)
311 Double_t muXe = fTR->GetMuXe(energyMeV);
312 Double_t muBu = fTR->GetMuBu(energyMeV);
313 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
316 // The distance after which the energy of the TR photon
318 absLength = gRandom->Exp(sigma);
319 if (absLength > AliTRDgeometry::DrThick()) continue;
321 // The position of the absorbtion
323 gMC->TrackPosition(pos);
324 posHit[0] = pos[0] + mom[0] / pTot * absLength;
325 posHit[1] = pos[1] + mom[1] / pTot * absLength;
326 posHit[2] = pos[2] + mom[2] / pTot * absLength;
329 Int_t q = ((Int_t) (energyeV / kWion));
331 // Add the hit to the array. TR photon hits are marked
332 // by negative charge
333 new(lhits[fNhits++]) AliTRDhit(fIshunt,gAlice->CurrentTrack()
342 //_____________________________________________________________________________
343 void AliTRDv1::Init()
346 // Initialise Transition Radiation Detector after geometry has been built.
351 printf(" Slow simulator\n\n");
354 printf(" Only plane %d is sensitive\n",fSensPlane);
355 if (fSensChamber >= 0)
356 printf(" Only chamber %d is sensitive\n",fSensChamber);
357 if (fSensSector >= 0) {
358 Int_t sens1 = fSensSector;
359 Int_t sens2 = fSensSector + fSensSectorRange;
360 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
361 * AliTRDgeometry::Nsect();
362 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
366 printf(" TR simulation on\n");
368 printf(" TR simulation off\n");
371 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
372 const Float_t kPoti = 12.1;
373 // Maximum energy (50 keV);
374 const Float_t kEend = 50000.0;
375 // Ermilova distribution for the delta-ray spectrum
376 Float_t poti = TMath::Log(kPoti);
377 Float_t eEnd = TMath::Log(kEend);
378 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
380 // Identifier of the sensitive volume (drift region)
381 fIdSens = gMC->VolId("UL05");
383 // Identifier of the TRD-driftchambers
384 fIdChamber1 = gMC->VolId("UCIO");
385 fIdChamber2 = gMC->VolId("UCIM");
386 fIdChamber3 = gMC->VolId("UCII");
388 for (Int_t i = 0; i < 80; i++) printf("*");
393 //_____________________________________________________________________________
394 AliTRDsim *AliTRDv1::CreateTR()
397 // Enables the simulation of TR
400 fTR = new AliTRDsim();
405 //_____________________________________________________________________________
406 void AliTRDv1::SetSensPlane(Int_t iplane)
409 // Defines the hit-sensitive plane (0-5)
412 if ((iplane < 0) || (iplane > 5)) {
413 printf("Wrong input value: %d\n",iplane);
414 printf("Use standard setting\n");
425 //_____________________________________________________________________________
426 void AliTRDv1::SetSensChamber(Int_t ichamber)
429 // Defines the hit-sensitive chamber (0-4)
432 if ((ichamber < 0) || (ichamber > 4)) {
433 printf("Wrong input value: %d\n",ichamber);
434 printf("Use standard setting\n");
441 fSensChamber = ichamber;
445 //_____________________________________________________________________________
446 void AliTRDv1::SetSensSector(Int_t isector)
449 // Defines the hit-sensitive sector (0-17)
452 SetSensSector(isector,1);
456 //_____________________________________________________________________________
457 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
460 // Defines a range of hit-sensitive sectors. The range is defined by
461 // <isector> (0-17) as the starting point and <nsector> as the number
462 // of sectors to be included.
465 if ((isector < 0) || (isector > 17)) {
466 printf("Wrong input value <isector>: %d\n",isector);
467 printf("Use standard setting\n");
469 fSensSectorRange = 0;
474 if ((nsector < 1) || (nsector > 18)) {
475 printf("Wrong input value <nsector>: %d\n",nsector);
476 printf("Use standard setting\n");
478 fSensSectorRange = 0;
484 fSensSector = isector;
485 fSensSectorRange = nsector;
489 //_____________________________________________________________________________
490 void AliTRDv1::StepManager()
493 // Slow simulator. Every charged track produces electron cluster as hits
494 // along its path across the drift volume. The step size is set acording
495 // to Bethe-Bloch. The energy distribution of the delta electrons follows
496 // a spectrum taken from Ermilova et al.
499 Int_t iIdSens, icSens;
500 Int_t iIdSpace, icSpace;
501 Int_t iIdChamber, icChamber;
516 Double_t betaGamma, pp;
518 TLorentzVector pos, mom;
519 TClonesArray &lhits = *fHits;
521 const Double_t kBig = 1.0E+12;
524 const Float_t kWion = 22.04;
525 // Maximum energy for e+ e- g for the step-size calculation
526 const Float_t kPTotMax = 0.002;
527 // Plateau value of the energy-loss for electron in xenon
528 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
529 //const Double_t kPlateau = 1.70;
530 // the averaged value (26/3/99)
531 const Float_t kPlateau = 1.55;
532 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
533 const Float_t kPrim = 48.0;
534 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
535 const Float_t kPoti = 12.1;
538 const Int_t kPdgElectron = 11;
540 // Set the maximum step size to a very large number for all
541 // neutral particles and those outside the driftvolume
542 gMC->SetMaxStep(kBig);
544 // Use only charged tracks
545 if (( gMC->TrackCharge() ) &&
546 (!gMC->IsTrackStop() ) &&
547 (!gMC->IsTrackDisappeared())) {
549 // Inside a sensitive volume?
550 iIdSens = gMC->CurrentVolID(icSens);
551 if (iIdSens == fIdSens) {
553 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
554 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
556 // Calculate the energy of the delta-electrons
557 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
558 eDelta = TMath::Max(eDelta,0.0);
560 // The number of secondary electrons created
561 qTot = ((Int_t) (eDelta / kWion) + 1);
563 // The hit coordinates and charge
564 gMC->TrackPosition(pos);
569 // The sector number (0 - 17)
570 // The numbering goes clockwise and starts at y = 0
571 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
576 sec = ((Int_t) (phi / 20));
578 // The chamber number
584 if (iIdChamber == fIdChamber1)
585 cha = (hits[2] < 0 ? 0 : 4);
586 else if (iIdChamber == fIdChamber2)
587 cha = (hits[2] < 0 ? 1 : 3);
588 else if (iIdChamber == fIdChamber3)
592 // The numbering starts at the innermost plane
593 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
595 // Check on selected volumes
596 Int_t addthishit = 1;
598 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
599 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
600 if (fSensSector >= 0) {
601 Int_t sens1 = fSensSector;
602 Int_t sens2 = fSensSector + fSensSectorRange;
603 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
604 * AliTRDgeometry::Nsect();
606 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
609 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
617 det = fGeometry->GetDetector(pla,cha,sec);
619 // Create the electron cluster from TR photons
620 if (fTR) CreateTRhit(det);
622 new(lhits[fNhits++]) AliTRDhit(fIshunt
623 ,gAlice->CurrentTrack()
628 // The energy loss according to Bethe Bloch
629 gMC->TrackMomentum(mom);
631 iPdg = TMath::Abs(gMC->TrackPid());
632 if ( (iPdg != kPdgElectron) ||
633 ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
634 aMass = gMC->TrackMass();
635 betaGamma = pTot / aMass;
636 pp = kPrim * BetheBloch(betaGamma);
637 // Take charge > 1 into account
638 charge = gMC->TrackCharge();
639 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
641 // Electrons above 20 Mev/c are at the plateau
643 pp = kPrim * kPlateau;
646 // Calculate the maximum step size for the next tracking step
650 while ((random[0] == 1.) || (random[0] == 0.));
651 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
656 // set step size to maximal value
657 gMC->SetMaxStep(kBig);
666 //_____________________________________________________________________________
667 Double_t AliTRDv1::BetheBloch(Double_t bg)
670 // Parametrization of the Bethe-Bloch-curve
671 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
674 // This parameters have been adjusted to averaged values from GEANT
675 const Double_t kP1 = 7.17960e-02;
676 const Double_t kP2 = 8.54196;
677 const Double_t kP3 = 1.38065e-06;
678 const Double_t kP4 = 5.30972;
679 const Double_t kP5 = 2.83798;
681 // This parameters have been adjusted to Xe-data found in:
682 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
683 //const Double_t kP1 = 0.76176E-1;
684 //const Double_t kP2 = 10.632;
685 //const Double_t kP3 = 3.17983E-6;
686 //const Double_t kP4 = 1.8631;
687 //const Double_t kP5 = 1.9479;
690 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
691 Double_t aa = TMath::Power(yy,kP4);
692 Double_t bb = TMath::Power((1./bg),kP5);
693 bb = TMath::Log(kP3 + bb);
694 return ((kP2 - aa - bb)*kP1 / aa);
701 //_____________________________________________________________________________
702 Double_t Ermilova(Double_t *x, Double_t *)
705 // Calculates the delta-ray energy distribution according to Ermilova.
706 // Logarithmic scale !
715 const Int_t kNv = 31;
717 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
718 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
719 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
720 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
721 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
722 , 9.4727, 9.9035,10.3735,10.5966,10.8198
725 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
726 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
727 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
728 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
729 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
730 , 0.04 , 0.023, 0.015, 0.011, 0.01
739 dpos = energy - vxe[pos2++];
743 if (pos2 > kNv) pos2 = kNv;
746 // Differentiate between the sampling points
747 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);