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 1.20 2000/06/08 18:32:58 cblume
19 Make code compliant to coding conventions
21 Revision 1.19 2000/06/07 16:27:32 cblume
22 Try to remove compiler warnings on Sun and HP
24 Revision 1.18 2000/05/08 16:17:27 cblume
27 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
28 Made inline function non-virtual. Bug fix in setting sensitive chamber
30 Revision 1.17 2000/02/28 19:10:26 cblume
31 Include the new TRD classes
33 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
34 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
36 Revision 1.16 1999/11/05 22:50:28 fca
37 Do not use Atan, removed from ROOT too
39 Revision 1.15 1999/11/02 17:20:19 fca
40 initialise nbytes before using it
42 Revision 1.14 1999/11/02 17:15:54 fca
43 Correct ansi scoping not accepted by HP compilers
45 Revision 1.13 1999/11/02 17:14:51 fca
46 Correct ansi scoping not accepted by HP compilers
48 Revision 1.12 1999/11/02 16:35:56 fca
49 New version of TRD introduced
51 Revision 1.11 1999/11/01 20:41:51 fca
52 Added protections against using the wrong version of FRAME
54 Revision 1.10 1999/09/29 09:24:35 fca
55 Introduction of the Copyright and cvs Log
59 ///////////////////////////////////////////////////////////////////////////////
61 // Transition Radiation Detector version 2 -- slow simulator //
65 <img src="picts/AliTRDfullClass.gif">
70 ///////////////////////////////////////////////////////////////////////////////
81 #include "AliTRDmatrix.h"
82 #include "AliTRDgeometry.h"
87 //_____________________________________________________________________________
88 AliTRDv1::AliTRDv1():AliTRD()
91 // Default constructor
104 fSensSectorRange = 0;
110 //_____________________________________________________________________________
111 AliTRDv1::AliTRDv1(const char *name, const char *title)
115 // Standard constructor for Transition Radiation Detector version 1
128 fSensSectorRange = 0;
132 SetBufferSize(128000);
136 //_____________________________________________________________________________
137 AliTRDv1::AliTRDv1(const AliTRDv1 &trd)
143 ((AliTRDv1 &) trd).Copy(*this);
147 //_____________________________________________________________________________
148 AliTRDv1::~AliTRDv1()
151 // AliTRDv1 destructor
154 if (fDeltaE) delete fDeltaE;
158 //_____________________________________________________________________________
159 AliTRDv1 &AliTRDv1::operator=(const AliTRDv1 &trd)
162 // Assignment operator
165 if (this != &trd) ((AliTRDv1 &) trd).Copy(*this);
170 //_____________________________________________________________________________
171 void AliTRDv1::Copy(AliTRDv1 &trd)
177 trd.fIdSens = fIdSens;
179 trd.fIdChamber1 = fIdChamber1;
180 trd.fIdChamber2 = fIdChamber2;
181 trd.fIdChamber3 = fIdChamber3;
183 trd.fSensSelect = fSensSelect;
184 trd.fSensPlane = fSensPlane;
185 trd.fSensChamber = fSensChamber;
186 trd.fSensSector = fSensSector;
187 trd.fSensSectorRange = fSensSectorRange;
193 //_____________________________________________________________________________
194 void AliTRDv1::CreateGeometry()
197 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
198 // This version covers the full azimuth.
201 // Check that FRAME is there otherwise we have no place where to put the TRD
202 AliModule* frame = gAlice->GetModule("FRAME");
205 // Define the chambers
206 AliTRD::CreateGeometry();
210 //_____________________________________________________________________________
211 void AliTRDv1::CreateMaterials()
214 // Create materials for the Transition Radiation Detector version 1
217 AliTRD::CreateMaterials();
221 //_____________________________________________________________________________
222 void AliTRDv1::Init()
225 // Initialise Transition Radiation Detector after geometry has been built.
230 printf(" Slow simulator\n\n");
233 printf(" Only plane %d is sensitive\n",fSensPlane);
234 if (fSensChamber >= 0)
235 printf(" Only chamber %d is sensitive\n",fSensChamber);
236 if (fSensSector >= 0) {
237 Int_t sens1 = fSensSector;
238 Int_t sens2 = fSensSector + fSensSectorRange;
239 sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
240 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
245 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
246 const Float_t kPoti = 12.1;
247 // Maximum energy (50 keV);
248 const Float_t kEend = 50000.0;
249 // Ermilova distribution for the delta-ray spectrum
250 Float_t poti = TMath::Log(kPoti);
251 Float_t eEnd = TMath::Log(kEend);
252 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
254 // Identifier of the sensitive volume (drift region)
255 fIdSens = gMC->VolId("UL05");
257 // Identifier of the TRD-driftchambers
258 fIdChamber1 = gMC->VolId("UCIO");
259 fIdChamber2 = gMC->VolId("UCIM");
260 fIdChamber3 = gMC->VolId("UCII");
262 for (Int_t i = 0; i < 80; i++) printf("*");
267 //_____________________________________________________________________________
268 void AliTRDv1::SetSensPlane(Int_t iplane)
271 // Defines the hit-sensitive plane (0-5)
274 if ((iplane < 0) || (iplane > 5)) {
275 printf("Wrong input value: %d\n",iplane);
276 printf("Use standard setting\n");
287 //_____________________________________________________________________________
288 void AliTRDv1::SetSensChamber(Int_t ichamber)
291 // Defines the hit-sensitive chamber (0-4)
294 if ((ichamber < 0) || (ichamber > 4)) {
295 printf("Wrong input value: %d\n",ichamber);
296 printf("Use standard setting\n");
303 fSensChamber = ichamber;
307 //_____________________________________________________________________________
308 void AliTRDv1::SetSensSector(Int_t isector)
311 // Defines the hit-sensitive sector (0-17)
314 SetSensSector(isector,1);
318 //_____________________________________________________________________________
319 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
322 // Defines a range of hit-sensitive sectors. The range is defined by
323 // <isector> (0-17) as the starting point and <nsector> as the number
324 // of sectors to be included.
327 if ((isector < 0) || (isector > 17)) {
328 printf("Wrong input value <isector>: %d\n",isector);
329 printf("Use standard setting\n");
331 fSensSectorRange = 0;
336 if ((nsector < 1) || (nsector > 18)) {
337 printf("Wrong input value <nsector>: %d\n",nsector);
338 printf("Use standard setting\n");
340 fSensSectorRange = 0;
346 fSensSector = isector;
347 fSensSectorRange = nsector;
351 //_____________________________________________________________________________
352 void AliTRDv1::StepManager()
355 // Slow simulator. Every charged track produces electron cluster as hits
356 // along its path across the drift volume. The step size is set acording
357 // to Bethe-Bloch. The energy distribution of the delta electrons follows
358 // a spectrum taken from Ermilova et al.
361 Int_t iIdSens, icSens;
362 Int_t iIdSpace, icSpace;
363 Int_t iIdChamber, icChamber;
379 Double_t betaGamma, pp;
381 TLorentzVector pos, mom;
382 TClonesArray &lhits = *fHits;
384 const Double_t kBig = 1.0E+12;
387 const Float_t kWion = 22.04;
388 // Maximum energy for e+ e- g for the step-size calculation
389 const Float_t kPTotMax = 0.002;
390 // Plateau value of the energy-loss for electron in xenon
391 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
392 //const Double_t kPlateau = 1.70;
393 // the averaged value (26/3/99)
394 const Float_t kPlateau = 1.55;
395 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
396 const Float_t kPrim = 48.0;
397 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
398 const Float_t kPoti = 12.1;
401 const Int_t kPdgElectron = 11;
403 // Set the maximum step size to a very large number for all
404 // neutral particles and those outside the driftvolume
405 gMC->SetMaxStep(kBig);
407 // Use only charged tracks
408 if (( gMC->TrackCharge() ) &&
409 (!gMC->IsTrackStop() ) &&
410 (!gMC->IsTrackDisappeared())) {
412 // Inside a sensitive volume?
413 iIdSens = gMC->CurrentVolID(icSens);
414 if (iIdSens == fIdSens) {
416 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
417 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
419 // Calculate the energy of the delta-electrons
420 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
421 eDelta = TMath::Max(eDelta,0.0);
423 // The number of secondary electrons created
424 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
426 // The hit coordinates and charge
427 gMC->TrackPosition(pos);
433 // The sector number (0 - 17)
434 // The numbering goes clockwise and starts at y = 0
435 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
440 sec = ((Int_t) (phi / 20));
442 // The chamber number
448 if (iIdChamber == fIdChamber1)
449 cha = (hits[2] < 0 ? 0 : 4);
450 else if (iIdChamber == fIdChamber2)
451 cha = (hits[2] < 0 ? 1 : 3);
452 else if (iIdChamber == fIdChamber3)
456 // The numbering starts at the innermost plane
457 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
459 // Check on selected volumes
460 Int_t addthishit = 1;
462 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
463 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
464 if (fSensSector >= 0) {
465 Int_t sens1 = fSensSector;
466 Int_t sens2 = fSensSector + fSensSectorRange;
467 sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
469 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
472 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
480 det[0] = fGeometry->GetDetector(pla,cha,sec);
481 new(lhits[fNhits++]) AliTRDhit(fIshunt
482 ,gAlice->CurrentTrack()
486 // The energy loss according to Bethe Bloch
487 gMC->TrackMomentum(mom);
489 iPdg = TMath::Abs(gMC->TrackPid());
490 if ( (iPdg != kPdgElectron) ||
491 ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
492 aMass = gMC->TrackMass();
493 betaGamma = pTot / aMass;
494 pp = kPrim * BetheBloch(betaGamma);
495 // Take charge > 1 into account
496 charge = gMC->TrackCharge();
497 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
499 // Electrons above 20 Mev/c are at the plateau
501 pp = kPrim * kPlateau;
504 // Calculate the maximum step size for the next tracking step
508 while ((random[0] == 1.) || (random[0] == 0.));
509 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
514 // set step size to maximal value
515 gMC->SetMaxStep(kBig);
524 //_____________________________________________________________________________
525 Double_t AliTRDv1::BetheBloch(Double_t bg)
528 // Parametrization of the Bethe-Bloch-curve
529 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
532 // This parameters have been adjusted to averaged values from GEANT
533 const Double_t kP1 = 7.17960e-02;
534 const Double_t kP2 = 8.54196;
535 const Double_t kP3 = 1.38065e-06;
536 const Double_t kP4 = 5.30972;
537 const Double_t kP5 = 2.83798;
539 // This parameters have been adjusted to Xe-data found in:
540 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
541 //const Double_t kP1 = 0.76176E-1;
542 //const Double_t kP2 = 10.632;
543 //const Double_t kP3 = 3.17983E-6;
544 //const Double_t kP4 = 1.8631;
545 //const Double_t kP5 = 1.9479;
548 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
549 Double_t aa = TMath::Power(yy,kP4);
550 Double_t bb = TMath::Power((1./bg),kP5);
551 bb = TMath::Log(kP3 + bb);
552 return ((kP2 - aa - bb)*kP1 / aa);
559 //_____________________________________________________________________________
560 Double_t Ermilova(Double_t *x, Double_t *)
563 // Calculates the delta-ray energy distribution according to Ermilova.
564 // Logarithmic scale !
573 const Int_t kNv = 31;
575 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
576 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
577 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
578 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
579 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
580 , 9.4727, 9.9035,10.3735,10.5966,10.8198
583 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
584 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
585 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
586 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
587 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
588 , 0.04 , 0.023, 0.015, 0.011, 0.01
597 dpos = energy - vxe[pos2++];
601 if (pos2 > kNv) pos2 = kNv;
604 // Differentiate between the sampling points
605 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);