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 1.27 2001/03/30 14:40:15 cblume
19 Update of the digitization parameter
21 Revision 1.26 2000/11/30 17:38:08 cblume
22 Changes to get in line with new STEER and EVGEN
24 Revision 1.25 2000/11/15 14:30:16 cblume
25 Fixed bug in calculating detector no. of extra hit
27 Revision 1.24 2000/11/10 14:58:36 cblume
28 Introduce additional hit with amplitude 0 at the chamber borders
30 Revision 1.23 2000/11/01 14:53:21 cblume
31 Merge with TRD-develop
33 Revision 1.17.2.5 2000/10/15 23:40:01 cblume
36 Revision 1.17.2.4 2000/10/06 16:49:46 cblume
39 Revision 1.17.2.3 2000/10/04 16:34:58 cblume
40 Replace include files by forward declarations
42 Revision 1.17.2.2 2000/09/18 13:50:17 cblume
43 Include TR photon generation and adapt to new AliTRDhit
45 Revision 1.22 2000/06/27 13:08:50 cblume
46 Changed to Copy(TObject &A) to appease the HP-compiler
48 Revision 1.21 2000/06/09 11:10:07 cblume
49 Compiler warnings and coding conventions, next round
51 Revision 1.20 2000/06/08 18:32:58 cblume
52 Make code compliant to coding conventions
54 Revision 1.19 2000/06/07 16:27:32 cblume
55 Try to remove compiler warnings on Sun and HP
57 Revision 1.18 2000/05/08 16:17:27 cblume
60 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
61 Made inline function non-virtual. Bug fix in setting sensitive chamber
63 Revision 1.17 2000/02/28 19:10:26 cblume
64 Include the new TRD classes
66 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
67 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
69 Revision 1.16 1999/11/05 22:50:28 fca
70 Do not use Atan, removed from ROOT too
72 Revision 1.15 1999/11/02 17:20:19 fca
73 initialise nbytes before using it
75 Revision 1.14 1999/11/02 17:15:54 fca
76 Correct ansi scoping not accepted by HP compilers
78 Revision 1.13 1999/11/02 17:14:51 fca
79 Correct ansi scoping not accepted by HP compilers
81 Revision 1.12 1999/11/02 16:35:56 fca
82 New version of TRD introduced
84 Revision 1.11 1999/11/01 20:41:51 fca
85 Added protections against using the wrong version of FRAME
87 Revision 1.10 1999/09/29 09:24:35 fca
88 Introduction of the Copyright and cvs Log
92 ///////////////////////////////////////////////////////////////////////////////
94 // Transition Radiation Detector version 1 -- slow simulator //
98 <img src="picts/AliTRDfullClass.gif">
103 ///////////////////////////////////////////////////////////////////////////////
111 #include <TLorentzVector.h>
115 #include "AliConst.h"
117 #include "AliTRDv1.h"
118 #include "AliTRDhit.h"
119 #include "AliTRDmatrix.h"
120 #include "AliTRDgeometry.h"
121 #include "AliTRDsim.h"
125 //_____________________________________________________________________________
126 AliTRDv1::AliTRDv1():AliTRD()
129 // Default constructor
143 fSensSectorRange = 0;
150 //_____________________________________________________________________________
151 AliTRDv1::AliTRDv1(const char *name, const char *title)
155 // Standard constructor for Transition Radiation Detector version 1
169 fSensSectorRange = 0;
174 SetBufferSize(128000);
178 //_____________________________________________________________________________
179 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
185 ((AliTRDv1 &) trd).Copy(*this);
189 //_____________________________________________________________________________
190 AliTRDv1::~AliTRDv1()
193 // AliTRDv1 destructor
196 if (fDeltaE) delete fDeltaE;
201 //_____________________________________________________________________________
202 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
205 // Assignment operator
208 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
213 //_____________________________________________________________________________
214 void AliTRDv1::Copy(TObject &trd)
220 ((AliTRDv1 &) trd).fIdSensDr = fIdSensDr;
221 ((AliTRDv1 &) trd).fIdSensAm = fIdSensAm;
223 ((AliTRDv1 &) trd).fIdChamber1 = fIdChamber1;
224 ((AliTRDv1 &) trd).fIdChamber2 = fIdChamber2;
225 ((AliTRDv1 &) trd).fIdChamber3 = fIdChamber3;
227 ((AliTRDv1 &) trd).fSensSelect = fSensSelect;
228 ((AliTRDv1 &) trd).fSensPlane = fSensPlane;
229 ((AliTRDv1 &) trd).fSensChamber = fSensChamber;
230 ((AliTRDv1 &) trd).fSensSector = fSensSector;
231 ((AliTRDv1 &) trd).fSensSectorRange = fSensSectorRange;
233 fDeltaE->Copy(*((AliTRDv1 &) trd).fDeltaE);
234 fTR->Copy(*((AliTRDv1 &) trd).fTR);
238 //_____________________________________________________________________________
239 void AliTRDv1::CreateGeometry()
242 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
243 // This version covers the full azimuth.
246 // Check that FRAME is there otherwise we have no place where to put the TRD
247 AliModule* frame = gAlice->GetModule("FRAME");
250 // Define the chambers
251 AliTRD::CreateGeometry();
255 //_____________________________________________________________________________
256 void AliTRDv1::CreateMaterials()
259 // Create materials for the Transition Radiation Detector version 1
262 AliTRD::CreateMaterials();
266 //_____________________________________________________________________________
267 void AliTRDv1::CreateTRhit(Int_t det)
270 // Creates an electron cluster from a TR photon.
271 // The photon is assumed to be created a the end of the radiator. The
272 // distance after which it deposits its energy takes into account the
273 // absorbtion of the entrance window and of the gas mixture in drift
278 const Int_t kPdgElectron = 11;
281 const Float_t kWion = 22.04;
283 // Maximum number of TR photons per track
284 const Int_t kNTR = 50;
286 TLorentzVector mom, pos;
287 TClonesArray &lhits = *fHits;
289 // Create TR at the entrance of the chamber
290 if (gMC->IsTrackEntering()) {
292 // Create TR only for electrons
293 Int_t iPdg = gMC->TrackPid();
294 if (TMath::Abs(iPdg) != kPdgElectron) return;
300 gMC->TrackMomentum(mom);
301 Float_t pTot = mom.Rho();
302 fTR->CreatePhotons(iPdg,pTot,nTR,eTR);
304 printf("AliTRDv1::CreateTRhit -- ");
305 printf("Boundary error: nTR = %d, kNTR = %d\n",nTR,kNTR);
309 // Loop through the TR photons
310 for (Int_t iTR = 0; iTR < nTR; iTR++) {
312 Float_t energyMeV = eTR[iTR] * 0.001;
313 Float_t energyeV = eTR[iTR] * 1000.0;
314 Float_t absLength = 0;
317 // Take the absorbtion in the entrance window into account
318 Double_t muMy = fTR->GetMuMy(energyMeV);
319 sigma = muMy * fFoilDensity;
320 absLength = gRandom->Exp(sigma);
321 if (absLength < AliTRDgeometry::MyThick()) continue;
323 // The absorbtion cross sections in the drift gas
325 // Gas-mixture (Xe/CO2)
326 Double_t muXe = fTR->GetMuXe(energyMeV);
327 Double_t muCO = fTR->GetMuCO(energyMeV);
328 sigma = (0.90 * muXe + 0.10 * muCO) * fGasDensity;
331 // Gas-mixture (Xe/Isobutane)
332 Double_t muXe = fTR->GetMuXe(energyMeV);
333 Double_t muBu = fTR->GetMuBu(energyMeV);
334 sigma = (0.97 * muXe + 0.03 * muBu) * fGasDensity;
337 // The distance after which the energy of the TR photon
339 absLength = gRandom->Exp(sigma);
340 if (absLength > AliTRDgeometry::DrThick()) continue;
342 // The position of the absorbtion
344 gMC->TrackPosition(pos);
345 posHit[0] = pos[0] + mom[0] / pTot * absLength;
346 posHit[1] = pos[1] + mom[1] / pTot * absLength;
347 posHit[2] = pos[2] + mom[2] / pTot * absLength;
350 Int_t q = ((Int_t) (energyeV / kWion));
352 // Add the hit to the array. TR photon hits are marked
353 // by negative charge
354 AliTRDhit *hit = new(lhits[fNhits++]) AliTRDhit(fIshunt
355 ,gAlice->CurrentTrack()
365 //_____________________________________________________________________________
366 void AliTRDv1::Init()
369 // Initialise Transition Radiation Detector after geometry has been built.
374 printf(" Slow simulator\n\n");
377 printf(" Only plane %d is sensitive\n",fSensPlane);
378 if (fSensChamber >= 0)
379 printf(" Only chamber %d is sensitive\n",fSensChamber);
380 if (fSensSector >= 0) {
381 Int_t sens1 = fSensSector;
382 Int_t sens2 = fSensSector + fSensSectorRange;
383 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
384 * AliTRDgeometry::Nsect();
385 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
389 printf(" TR simulation on\n");
391 printf(" TR simulation off\n");
394 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
395 const Float_t kPoti = 12.1;
396 // Maximum energy (50 keV);
397 const Float_t kEend = 50000.0;
398 // Ermilova distribution for the delta-ray spectrum
399 Float_t poti = TMath::Log(kPoti);
400 Float_t eEnd = TMath::Log(kEend);
401 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
403 // Identifier of the sensitive volume (drift region)
404 fIdSensDr = gMC->VolId("UL05");
405 // Identifier of the sensitive volume (amplification region)
406 fIdSensAm = gMC->VolId("UL06");
408 // Identifier of the TRD-driftchambers
409 fIdChamber1 = gMC->VolId("UCIO");
410 fIdChamber2 = gMC->VolId("UCIM");
411 fIdChamber3 = gMC->VolId("UCII");
413 for (Int_t i = 0; i < 80; i++) printf("*");
418 //_____________________________________________________________________________
419 AliTRDsim *AliTRDv1::CreateTR()
422 // Enables the simulation of TR
425 fTR = new AliTRDsim();
430 //_____________________________________________________________________________
431 void AliTRDv1::SetSensPlane(Int_t iplane)
434 // Defines the hit-sensitive plane (0-5)
437 if ((iplane < 0) || (iplane > 5)) {
438 printf("Wrong input value: %d\n",iplane);
439 printf("Use standard setting\n");
450 //_____________________________________________________________________________
451 void AliTRDv1::SetSensChamber(Int_t ichamber)
454 // Defines the hit-sensitive chamber (0-4)
457 if ((ichamber < 0) || (ichamber > 4)) {
458 printf("Wrong input value: %d\n",ichamber);
459 printf("Use standard setting\n");
466 fSensChamber = ichamber;
470 //_____________________________________________________________________________
471 void AliTRDv1::SetSensSector(Int_t isector)
474 // Defines the hit-sensitive sector (0-17)
477 SetSensSector(isector,1);
481 //_____________________________________________________________________________
482 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
485 // Defines a range of hit-sensitive sectors. The range is defined by
486 // <isector> (0-17) as the starting point and <nsector> as the number
487 // of sectors to be included.
490 if ((isector < 0) || (isector > 17)) {
491 printf("Wrong input value <isector>: %d\n",isector);
492 printf("Use standard setting\n");
494 fSensSectorRange = 0;
499 if ((nsector < 1) || (nsector > 18)) {
500 printf("Wrong input value <nsector>: %d\n",nsector);
501 printf("Use standard setting\n");
503 fSensSectorRange = 0;
509 fSensSector = isector;
510 fSensSectorRange = nsector;
514 //_____________________________________________________________________________
515 void AliTRDv1::StepManager()
518 // Slow simulator. Every charged track produces electron cluster as hits
519 // along its path across the drift volume. The step size is set acording
520 // to Bethe-Bloch. The energy distribution of the delta electrons follows
521 // a spectrum taken from Ermilova et al.
524 Int_t iIdSens, icSens;
525 Int_t iIdChamber, icChamber;
541 Double_t betaGamma, pp;
544 TLorentzVector pos, mom;
545 TClonesArray &lhits = *fHits;
547 const Double_t kBig = 1.0E+12;
550 const Float_t kWion = 22.04;
551 // Maximum momentum for e+ e- g
552 const Float_t kPTotMaxEl = 0.002;
553 // Minimum energy for the step size adjustment
554 const Float_t kEkinMinStep = 1.0e-5;
555 // Plateau value of the energy-loss for electron in xenon
556 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
557 //const Double_t kPlateau = 1.70;
558 // the averaged value (26/3/99)
559 const Float_t kPlateau = 1.55;
560 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
561 const Float_t kPrim = 48.0;
562 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
563 const Float_t kPoti = 12.1;
566 const Int_t kPdgElectron = 11;
568 // Set the maximum step size to a very large number for all
569 // neutral particles and those outside the driftvolume
570 gMC->SetMaxStep(kBig);
572 // Use only charged tracks
573 if (( gMC->TrackCharge() ) &&
574 (!gMC->IsTrackStop() ) &&
575 (!gMC->IsTrackDisappeared())) {
577 // Inside a sensitive volume?
578 iIdSens = gMC->CurrentVolID(icSens);
579 if ((iIdSens == fIdSensDr) ||
580 (iIdSens == fIdSensAm)) {
582 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
584 // The hit coordinates and charge
585 gMC->TrackPosition(pos);
590 // The sector number (0 - 17)
591 // The numbering goes clockwise and starts at y = 0
592 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
597 sec = ((Int_t) (phi / 20));
599 // The chamber number
605 if (iIdChamber == fIdChamber1)
606 cha = (hits[2] < 0 ? 0 : 4);
607 else if (iIdChamber == fIdChamber2)
608 cha = (hits[2] < 0 ? 1 : 3);
609 else if (iIdChamber == fIdChamber3)
613 // The numbering starts at the innermost plane
614 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
616 // Check on selected volumes
617 Int_t addthishit = 1;
619 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
620 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
621 if (fSensSector >= 0) {
622 Int_t sens1 = fSensSector;
623 Int_t sens2 = fSensSector + fSensSectorRange;
624 sens2 -= ((Int_t) (sens2 / AliTRDgeometry::Nsect()))
625 * AliTRDgeometry::Nsect();
627 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
630 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
638 // The detector number
639 det = fGeometry->GetDetector(pla,cha,sec);
641 // Special hits and TR photons only in the drift region
642 if (iIdSens == fIdSensDr) {
644 // Create some special hits with amplitude 0 at the entrance and
645 // exit of each chamber that contain the momentum components of the particle
646 if (gMC->IsTrackEntering() || gMC->IsTrackExiting()) {
647 gMC->TrackMomentum(mom);
651 AliTRDhit *hitTest = new(lhits[fNhits++]) AliTRDhit(fIshunt
652 ,gAlice->CurrentTrack()
657 // Create the hits from TR photons
658 if (fTR) CreateTRhit(det);
662 // Calculate the energy of the delta-electrons
663 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
664 eDelta = TMath::Max(eDelta,0.0);
666 // The number of secondary electrons created
667 qTot = ((Int_t) (eDelta / kWion) + 1);
669 // Create a new dEdx hit
670 AliTRDhit *hit = new(lhits[fNhits++]) AliTRDhit(fIshunt
671 ,gAlice->CurrentTrack()
673 if (iIdSens == fIdSensDr) {
677 hit->SetAmplification();
680 // Calculate the maximum step size for the next tracking step
681 // Produce only one hit if Ekin is below cutoff
682 aMass = gMC->TrackMass();
683 if ((gMC->Etot() - aMass) > kEkinMinStep) {
685 // The energy loss according to Bethe Bloch
686 iPdg = TMath::Abs(gMC->TrackPid());
687 if ( (iPdg != kPdgElectron) ||
688 ((iPdg == kPdgElectron) && (pTot < kPTotMaxEl))) {
689 gMC->TrackMomentum(mom);
691 betaGamma = pTot / aMass;
692 pp = kPrim * BetheBloch(betaGamma);
693 // Take charge > 1 into account
694 charge = gMC->TrackCharge();
695 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
697 // Electrons above 20 Mev/c are at the plateau
699 pp = kPrim * kPlateau;
705 while ((random[0] == 1.) || (random[0] == 0.));
706 stepSize = - TMath::Log(random[0]) / pp;
707 gMC->SetMaxStep(stepSize);
720 //_____________________________________________________________________________
721 Double_t AliTRDv1::BetheBloch(Double_t bg)
724 // Parametrization of the Bethe-Bloch-curve
725 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
728 // This parameters have been adjusted to averaged values from GEANT
729 const Double_t kP1 = 7.17960e-02;
730 const Double_t kP2 = 8.54196;
731 const Double_t kP3 = 1.38065e-06;
732 const Double_t kP4 = 5.30972;
733 const Double_t kP5 = 2.83798;
735 // This parameters have been adjusted to Xe-data found in:
736 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
737 //const Double_t kP1 = 0.76176E-1;
738 //const Double_t kP2 = 10.632;
739 //const Double_t kP3 = 3.17983E-6;
740 //const Double_t kP4 = 1.8631;
741 //const Double_t kP5 = 1.9479;
743 // Lower cutoff of the Bethe-Bloch-curve to limit step sizes
744 const Double_t kBgMin = 0.8;
745 const Double_t kBBMax = 6.83298;
746 //const Double_t kBgMin = 0.6;
747 //const Double_t kBBMax = 17.2809;
748 //const Double_t kBgMin = 0.4;
749 //const Double_t kBBMax = 82.0;
752 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
753 Double_t aa = TMath::Power(yy,kP4);
754 Double_t bb = TMath::Power((1./bg),kP5);
755 bb = TMath::Log(kP3 + bb);
756 return ((kP2 - aa - bb)*kP1 / aa);
764 //_____________________________________________________________________________
765 Double_t Ermilova(Double_t *x, Double_t *)
768 // Calculates the delta-ray energy distribution according to Ermilova.
769 // Logarithmic scale !
778 const Int_t kNv = 31;
780 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
781 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
782 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
783 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
784 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
785 , 9.4727, 9.9035,10.3735,10.5966,10.8198
788 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
789 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
790 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
791 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
792 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
793 , 0.04 , 0.023, 0.015, 0.011, 0.01
802 dpos = energy - vxe[pos2++];
806 if (pos2 > kNv) pos2 = kNv - 1;
809 // Differentiate between the sampling points
810 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);