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 1.19 2000/06/07 16:27:32 cblume
19 Try to remove compiler warnings on Sun and HP
21 Revision 1.18 2000/05/08 16:17:27 cblume
24 Revision 1.17.2.1 2000/05/08 14:59:16 cblume
25 Made inline function non-virtual. Bug fix in setting sensitive chamber
27 Revision 1.17 2000/02/28 19:10:26 cblume
28 Include the new TRD classes
30 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
31 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
33 Revision 1.16 1999/11/05 22:50:28 fca
34 Do not use Atan, removed from ROOT too
36 Revision 1.15 1999/11/02 17:20:19 fca
37 initialise nbytes before using it
39 Revision 1.14 1999/11/02 17:15:54 fca
40 Correct ansi scoping not accepted by HP compilers
42 Revision 1.13 1999/11/02 17:14:51 fca
43 Correct ansi scoping not accepted by HP compilers
45 Revision 1.12 1999/11/02 16:35:56 fca
46 New version of TRD introduced
48 Revision 1.11 1999/11/01 20:41:51 fca
49 Added protections against using the wrong version of FRAME
51 Revision 1.10 1999/09/29 09:24:35 fca
52 Introduction of the Copyright and cvs Log
56 ///////////////////////////////////////////////////////////////////////////////
58 // Transition Radiation Detector version 2 -- slow simulator //
62 <img src="picts/AliTRDfullClass.gif">
67 ///////////////////////////////////////////////////////////////////////////////
78 #include "AliTRDmatrix.h"
79 #include "AliTRDgeometry.h"
84 //_____________________________________________________________________________
85 AliTRDv1::AliTRDv1():AliTRD()
88 // Default constructor
101 fSensSectorRange = 0;
107 //_____________________________________________________________________________
108 AliTRDv1::AliTRDv1(const char *name, const char *title)
112 // Standard constructor for Transition Radiation Detector version 1
125 fSensSectorRange = 0;
129 SetBufferSize(128000);
133 //_____________________________________________________________________________
134 AliTRDv1::AliTRDv1(AliTRDv1 &trd)
144 //_____________________________________________________________________________
145 AliTRDv1::~AliTRDv1()
148 if (fDeltaE) delete fDeltaE;
153 //_____________________________________________________________________________
154 void AliTRDv1::Copy(AliTRDv1 &trd)
160 trd.fIdSens = fIdSens;
162 trd.fIdChamber1 = fIdChamber1;
163 trd.fIdChamber2 = fIdChamber2;
164 trd.fIdChamber3 = fIdChamber3;
166 trd.fSensSelect = fSensSelect;
167 trd.fSensPlane = fSensPlane;
168 trd.fSensChamber = fSensChamber;
169 trd.fSensSector = fSensSector;
170 trd.fSensSectorRange = fSensSectorRange;
176 //_____________________________________________________________________________
177 void AliTRDv1::CreateGeometry()
180 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
181 // This version covers the full azimuth.
184 // Check that FRAME is there otherwise we have no place where to put the TRD
185 AliModule* frame = gAlice->GetModule("FRAME");
188 // Define the chambers
189 AliTRD::CreateGeometry();
193 //_____________________________________________________________________________
194 void AliTRDv1::CreateMaterials()
197 // Create materials for the Transition Radiation Detector version 1
200 AliTRD::CreateMaterials();
204 //_____________________________________________________________________________
205 void AliTRDv1::Init()
208 // Initialise Transition Radiation Detector after geometry has been built.
213 printf(" Slow simulator\n\n");
216 printf(" Only plane %d is sensitive\n",fSensPlane);
217 if (fSensChamber >= 0)
218 printf(" Only chamber %d is sensitive\n",fSensChamber);
219 if (fSensSector >= 0) {
220 Int_t sens1 = fSensSector;
221 Int_t sens2 = fSensSector + fSensSectorRange;
222 sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
223 printf(" Only sectors %d - %d are sensitive\n",sens1,sens2-1);
228 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
229 const Float_t kPoti = 12.1;
230 // Maximum energy (50 keV);
231 const Float_t kEend = 50000.0;
232 // Ermilova distribution for the delta-ray spectrum
233 Float_t poti = TMath::Log(kPoti);
234 Float_t eEnd = TMath::Log(kEend);
235 fDeltaE = new TF1("deltae",Ermilova,poti,eEnd,0);
237 // Identifier of the sensitive volume (drift region)
238 fIdSens = gMC->VolId("UL05");
240 // Identifier of the TRD-driftchambers
241 fIdChamber1 = gMC->VolId("UCIO");
242 fIdChamber2 = gMC->VolId("UCIM");
243 fIdChamber3 = gMC->VolId("UCII");
245 for (Int_t i = 0; i < 80; i++) printf("*");
250 //_____________________________________________________________________________
251 void AliTRDv1::SetSensPlane(Int_t iplane)
254 // Defines the hit-sensitive plane (0-5)
257 if ((iplane < 0) || (iplane > 5)) {
258 printf("Wrong input value: %d\n",iplane);
259 printf("Use standard setting\n");
270 //_____________________________________________________________________________
271 void AliTRDv1::SetSensChamber(Int_t ichamber)
274 // Defines the hit-sensitive chamber (0-4)
277 if ((ichamber < 0) || (ichamber > 4)) {
278 printf("Wrong input value: %d\n",ichamber);
279 printf("Use standard setting\n");
286 fSensChamber = ichamber;
290 //_____________________________________________________________________________
291 void AliTRDv1::SetSensSector(Int_t isector)
294 // Defines the hit-sensitive sector (0-17)
297 SetSensSector(isector,1);
301 //_____________________________________________________________________________
302 void AliTRDv1::SetSensSector(Int_t isector, Int_t nsector)
305 // Defines a range of hit-sensitive sectors. The range is defined by
306 // <isector> (0-17) as the starting point and <nsector> as the number
307 // of sectors to be included.
310 if ((isector < 0) || (isector > 17)) {
311 printf("Wrong input value <isector>: %d\n",isector);
312 printf("Use standard setting\n");
314 fSensSectorRange = 0;
319 if ((nsector < 1) || (nsector > 18)) {
320 printf("Wrong input value <nsector>: %d\n",nsector);
321 printf("Use standard setting\n");
323 fSensSectorRange = 0;
329 fSensSector = isector;
330 fSensSectorRange = nsector;
334 //_____________________________________________________________________________
335 void AliTRDv1::StepManager()
338 // Slow simulator. Every charged track produces electron cluster as hits
339 // along its path across the drift volume. The step size is set acording
340 // to Bethe-Bloch. The energy distribution of the delta electrons follows
341 // a spectrum taken from Ermilova et al.
344 Int_t iIdSens, icSens;
345 Int_t iIdSpace, icSpace;
346 Int_t iIdChamber, icChamber;
362 Double_t betaGamma, pp;
364 TLorentzVector pos, mom;
365 TClonesArray &lhits = *fHits;
367 const Double_t kBig = 1.0E+12;
370 const Float_t kWion = 22.04;
371 // Maximum energy for e+ e- g for the step-size calculation
372 const Float_t kPTotMax = 0.002;
373 // Plateau value of the energy-loss for electron in xenon
374 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
375 //const Double_t kPlateau = 1.70;
376 // the averaged value (26/3/99)
377 const Float_t kPlateau = 1.55;
378 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
379 const Float_t kPrim = 48.0;
380 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
381 const Float_t kPoti = 12.1;
384 const Int_t kPdgElectron = 11;
386 // Set the maximum step size to a very large number for all
387 // neutral particles and those outside the driftvolume
388 gMC->SetMaxStep(kBig);
390 // Use only charged tracks
391 if (( gMC->TrackCharge() ) &&
392 (!gMC->IsTrackStop() ) &&
393 (!gMC->IsTrackDisappeared())) {
395 // Inside a sensitive volume?
396 iIdSens = gMC->CurrentVolID(icSens);
397 if (iIdSens == fIdSens) {
399 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
400 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
402 // Calculate the energy of the delta-electrons
403 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
404 eDelta = TMath::Max(eDelta,0.0);
406 // The number of secondary electrons created
407 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
409 // The hit coordinates and charge
410 gMC->TrackPosition(pos);
416 // The sector number (0 - 17)
417 // The numbering goes clockwise and starts at y = 0
418 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
423 sec = ((Int_t) (phi / 20));
425 // The chamber number
431 if (iIdChamber == fIdChamber1)
432 cha = (hits[2] < 0 ? 0 : 4);
433 else if (iIdChamber == fIdChamber2)
434 cha = (hits[2] < 0 ? 1 : 3);
435 else if (iIdChamber == fIdChamber3)
439 // The numbering starts at the innermost plane
440 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
442 // Check on selected volumes
443 Int_t addthishit = 1;
445 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
446 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
447 if (fSensSector >= 0) {
448 Int_t sens1 = fSensSector;
449 Int_t sens2 = fSensSector + fSensSectorRange;
450 sens2 -= ((Int_t) (sens2 / kNsect)) * kNsect;
452 if ((sec < sens1) || (sec >= sens2)) addthishit = 0;
455 if ((sec < sens1) && (sec >= sens2)) addthishit = 0;
463 det[0] = fGeometry->GetDetector(pla,cha,sec);
464 new(lhits[fNhits++]) AliTRDhit(fIshunt
465 ,gAlice->CurrentTrack()
469 // The energy loss according to Bethe Bloch
470 gMC->TrackMomentum(mom);
472 iPdg = TMath::Abs(gMC->TrackPid());
473 if ( (iPdg != kPdgElectron) ||
474 ((iPdg == kPdgElectron) && (pTot < kPTotMax))) {
475 aMass = gMC->TrackMass();
476 betaGamma = pTot / aMass;
477 pp = kPrim * BetheBloch(betaGamma);
478 // Take charge > 1 into account
479 charge = gMC->TrackCharge();
480 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
482 // Electrons above 20 Mev/c are at the plateau
484 pp = kPrim * kPlateau;
487 // Calculate the maximum step size for the next tracking step
491 while ((random[0] == 1.) || (random[0] == 0.));
492 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
497 // set step size to maximal value
498 gMC->SetMaxStep(kBig);
507 //_____________________________________________________________________________
508 Double_t AliTRDv1::BetheBloch(Double_t bg)
511 // Parametrization of the Bethe-Bloch-curve
512 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
515 // This parameters have been adjusted to averaged values from GEANT
516 const Double_t kP1 = 7.17960e-02;
517 const Double_t kP2 = 8.54196;
518 const Double_t kP3 = 1.38065e-06;
519 const Double_t kP4 = 5.30972;
520 const Double_t kP5 = 2.83798;
522 // This parameters have been adjusted to Xe-data found in:
523 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
524 //const Double_t kP1 = 0.76176E-1;
525 //const Double_t kP2 = 10.632;
526 //const Double_t kP3 = 3.17983E-6;
527 //const Double_t kP4 = 1.8631;
528 //const Double_t kP5 = 1.9479;
531 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
532 Double_t aa = TMath::Power(yy,kP4);
533 Double_t bb = TMath::Power((1./bg),kP5);
534 bb = TMath::Log(kP3 + bb);
535 return ((kP2 - aa - bb)*kP1 / aa);
542 //_____________________________________________________________________________
543 Double_t Ermilova(Double_t *x, Double_t *)
546 // Calculates the delta-ray energy distribution according to Ermilova.
547 // Logarithmic scale !
556 const Int_t kNv = 31;
558 Float_t vxe[kNv] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
559 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
560 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
561 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
562 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
563 , 9.4727, 9.9035,10.3735,10.5966,10.8198
566 Float_t vye[kNv] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
567 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
568 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
569 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
570 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
571 , 0.04 , 0.023, 0.015, 0.011, 0.01
580 dpos = energy - vxe[pos2++];
584 if (pos2 > kNv) pos2 = kNv;
587 // Differentiate between the sampling points
588 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);