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 1.17.2.1 2000/05/08 14:59:16 cblume
19 Made inline function non-virtual. Bug fix in setting sensitive chamber
21 Revision 1.17 2000/02/28 19:10:26 cblume
22 Include the new TRD classes
24 Revision 1.16.4.1 2000/02/28 18:04:35 cblume
25 Change to new hit version, introduce geometry class, and move digitization and clustering to AliTRDdigitizer/AliTRDclusterizerV1
27 Revision 1.16 1999/11/05 22:50:28 fca
28 Do not use Atan, removed from ROOT too
30 Revision 1.15 1999/11/02 17:20:19 fca
31 initialise nbytes before using it
33 Revision 1.14 1999/11/02 17:15:54 fca
34 Correct ansi scoping not accepted by HP compilers
36 Revision 1.13 1999/11/02 17:14:51 fca
37 Correct ansi scoping not accepted by HP compilers
39 Revision 1.12 1999/11/02 16:35:56 fca
40 New version of TRD introduced
42 Revision 1.11 1999/11/01 20:41:51 fca
43 Added protections against using the wrong version of FRAME
45 Revision 1.10 1999/09/29 09:24:35 fca
46 Introduction of the Copyright and cvs Log
50 ///////////////////////////////////////////////////////////////////////////////
52 // Transition Radiation Detector version 2 -- slow simulator //
56 <img src="picts/AliTRDfullClass.gif">
61 ///////////////////////////////////////////////////////////////////////////////
72 #include "AliTRDmatrix.h"
73 #include "AliTRDgeometry.h"
77 //_____________________________________________________________________________
78 AliTRDv1::AliTRDv1(const char *name, const char *title)
82 // Standard constructor for Transition Radiation Detector version 1
98 SetBufferSize(128000);
102 //_____________________________________________________________________________
103 AliTRDv1::~AliTRDv1()
106 if (fDeltaE) delete fDeltaE;
110 //_____________________________________________________________________________
111 void AliTRDv1::CreateGeometry()
114 // Create the GEANT geometry for the Transition Radiation Detector - Version 1
115 // This version covers the full azimuth.
118 // Check that FRAME is there otherwise we have no place where to put the TRD
119 AliModule* FRAME = gAlice->GetModule("FRAME");
122 // Define the chambers
123 AliTRD::CreateGeometry();
127 //_____________________________________________________________________________
128 void AliTRDv1::CreateMaterials()
131 // Create materials for the Transition Radiation Detector version 1
134 AliTRD::CreateMaterials();
138 //_____________________________________________________________________________
139 void AliTRDv1::Init()
142 // Initialise Transition Radiation Detector after geometry has been built.
147 printf(" Slow simulator\n\n");
150 printf(" Only plane %d is sensitive\n",fSensPlane);
151 if (fSensChamber >= 0)
152 printf(" Only chamber %d is sensitive\n",fSensChamber);
153 if (fSensSector >= 0)
154 printf(" Only sector %d is sensitive\n",fSensSector);
158 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
159 const Float_t kPoti = 12.1;
160 // Maximum energy (50 keV);
161 const Float_t kEend = 50000.0;
162 // Ermilova distribution for the delta-ray spectrum
163 Float_t Poti = TMath::Log(kPoti);
164 Float_t Eend = TMath::Log(kEend);
165 fDeltaE = new TF1("deltae",Ermilova,Poti,Eend,0);
167 // Identifier of the sensitive volume (drift region)
168 fIdSens = gMC->VolId("UL05");
170 // Identifier of the TRD-driftchambers
171 fIdChamber1 = gMC->VolId("UCIO");
172 fIdChamber2 = gMC->VolId("UCIM");
173 fIdChamber3 = gMC->VolId("UCII");
175 for (Int_t i = 0; i < 80; i++) printf("*");
180 //_____________________________________________________________________________
181 void AliTRDv1::SetSensPlane(Int_t iplane)
184 // Defines the hit-sensitive plane (0-5)
187 if ((iplane < 0) || (iplane > 5)) {
188 printf("Wrong input value: %d\n",iplane);
189 printf("Use standard setting\n");
200 //_____________________________________________________________________________
201 void AliTRDv1::SetSensChamber(Int_t ichamber)
204 // Defines the hit-sensitive chamber (0-4)
207 if ((ichamber < 0) || (ichamber > 4)) {
208 printf("Wrong input value: %d\n",ichamber);
209 printf("Use standard setting\n");
216 fSensChamber = ichamber;
220 //_____________________________________________________________________________
221 void AliTRDv1::SetSensSector(Int_t isector)
224 // Defines the hit-sensitive sector (0-17)
227 if ((isector < 0) || (isector > 17)) {
228 printf("Wrong input value: %d\n",isector);
229 printf("Use standard setting\n");
236 fSensSector = isector;
240 //_____________________________________________________________________________
241 void AliTRDv1::StepManager()
244 // Slow simulator. Every charged track produces electron cluster as hits
245 // along its path across the drift volume. The step size is set acording
246 // to Bethe-Bloch. The energy distribution of the delta electrons follows
247 // a spectrum taken from Ermilova et al.
250 Int_t iIdSens, icSens;
251 Int_t iIdSpace, icSpace;
252 Int_t iIdChamber, icChamber;
266 Double_t betaGamma, pp;
268 TLorentzVector pos, mom;
269 TClonesArray &lhits = *fHits;
271 const Double_t kBig = 1.0E+12;
274 const Float_t kWion = 22.04;
275 // Maximum energy for e+ e- g for the step-size calculation
276 const Float_t kPTotMax = 0.002;
277 // Plateau value of the energy-loss for electron in xenon
278 // taken from: Allison + Comb, Ann. Rev. Nucl. Sci. (1980), 30, 253
279 //const Double_t kPlateau = 1.70;
280 // the averaged value (26/3/99)
281 const Float_t kPlateau = 1.55;
282 // dN1/dx|min for the gas mixture (90% Xe + 10% CO2)
283 const Float_t kPrim = 48.0;
284 // First ionization potential (eV) for the gas mixture (90% Xe + 10% CO2)
285 const Float_t kPoti = 12.1;
288 const Int_t pdgElectron = 11;
290 // Set the maximum step size to a very large number for all
291 // neutral particles and those outside the driftvolume
292 gMC->SetMaxStep(kBig);
294 // Use only charged tracks
295 if (( gMC->TrackCharge() ) &&
296 (!gMC->IsTrackStop() ) &&
297 (!gMC->IsTrackDisappeared())) {
299 // Inside a sensitive volume?
300 iIdSens = gMC->CurrentVolID(icSens);
301 if (iIdSens == fIdSens) {
303 iIdSpace = gMC->CurrentVolOffID(4,icSpace );
304 iIdChamber = gMC->CurrentVolOffID(1,icChamber);
306 // Calculate the energy of the delta-electrons
307 eDelta = TMath::Exp(fDeltaE->GetRandom()) - kPoti;
308 eDelta = TMath::Max(eDelta,0.0);
310 // The number of secondary electrons created
311 qTot = (Double_t) ((Int_t) (eDelta / kWion) + 1);
313 // The hit coordinates and charge
314 gMC->TrackPosition(pos);
320 // The sector number (0 - 17)
321 // The numbering goes clockwise and starts at y = 0
322 Float_t phi = kRaddeg*TMath::ATan2(pos[0],pos[1]);
327 sec = ((Int_t) (phi / 20));
329 // The chamber number
335 if (iIdChamber == fIdChamber1)
336 cha = (hits[2] < 0 ? 0 : 4);
337 else if (iIdChamber == fIdChamber2)
338 cha = (hits[2] < 0 ? 1 : 3);
339 else if (iIdChamber == fIdChamber3)
343 // The numbering starts at the innermost plane
344 pla = icChamber - TMath::Nint((Float_t) (icChamber / 7)) * 6 - 1;
346 // Check on selected volumes
347 Int_t addthishit = 1;
349 if ((fSensPlane >= 0) && (pla != fSensPlane )) addthishit = 0;
350 if ((fSensChamber >= 0) && (cha != fSensChamber)) addthishit = 0;
351 if ((fSensSector >= 0) && (sec != fSensSector )) addthishit = 0;
357 new(lhits[fNhits++]) AliTRDhit(fIshunt
358 ,gAlice->CurrentTrack()
359 ,fGeometry->GetDetector(pla,cha,sec)
362 // The energy loss according to Bethe Bloch
363 gMC->TrackMomentum(mom);
365 iPdg = TMath::Abs(gMC->TrackPid());
366 if ( (iPdg != pdgElectron) ||
367 ((iPdg == pdgElectron) && (pTot < kPTotMax))) {
368 aMass = gMC->TrackMass();
369 betaGamma = pTot / aMass;
370 pp = kPrim * BetheBloch(betaGamma);
371 // Take charge > 1 into account
372 charge = gMC->TrackCharge();
373 if (TMath::Abs(charge) > 1) pp = pp * charge*charge;
375 // Electrons above 20 Mev/c are at the plateau
377 pp = kPrim * kPlateau;
380 // Calculate the maximum step size for the next tracking step
384 while ((random[0] == 1.) || (random[0] == 0.));
385 gMC->SetMaxStep( - TMath::Log(random[0]) / pp);
390 // set step size to maximal value
391 gMC->SetMaxStep(kBig);
400 //_____________________________________________________________________________
401 Double_t AliTRDv1::BetheBloch(Double_t bg)
404 // Parametrization of the Bethe-Bloch-curve
405 // The parametrization is the same as for the TPC and is taken from Lehrhaus.
408 // This parameters have been adjusted to averaged values from GEANT
409 const Double_t kP1 = 7.17960e-02;
410 const Double_t kP2 = 8.54196;
411 const Double_t kP3 = 1.38065e-06;
412 const Double_t kP4 = 5.30972;
413 const Double_t kP5 = 2.83798;
415 // This parameters have been adjusted to Xe-data found in:
416 // Allison & Cobb, Ann. Rev. Nucl. Sci. (1980), 30, 253
417 //const Double_t kP1 = 0.76176E-1;
418 //const Double_t kP2 = 10.632;
419 //const Double_t kP3 = 3.17983E-6;
420 //const Double_t kP4 = 1.8631;
421 //const Double_t kP5 = 1.9479;
424 Double_t yy = bg / TMath::Sqrt(1. + bg*bg);
425 Double_t aa = TMath::Power(yy,kP4);
426 Double_t bb = TMath::Power((1./bg),kP5);
427 bb = TMath::Log(kP3 + bb);
428 return ((kP2 - aa - bb)*kP1 / aa);
435 //_____________________________________________________________________________
436 Double_t Ermilova(Double_t *x, Double_t *)
439 // Calculates the delta-ray energy distribution according to Ermilova.
440 // Logarithmic scale !
451 Float_t vxe[nV] = { 2.3026, 2.9957, 3.4012, 3.6889, 3.9120
452 , 4.0943, 4.2485, 4.3820, 4.4998, 4.6052
453 , 4.7005, 5.0752, 5.2983, 5.7038, 5.9915
454 , 6.2146, 6.5221, 6.9078, 7.3132, 7.6009
455 , 8.0064, 8.5172, 8.6995, 8.9872, 9.2103
456 , 9.4727, 9.9035,10.3735,10.5966,10.8198
459 Float_t vye[nV] = { 80.0 , 31.0 , 23.3 , 21.1 , 21.0
460 , 20.9 , 20.8 , 20.0 , 16.0 , 11.0
461 , 8.0 , 6.0 , 5.2 , 4.6 , 4.0
462 , 3.5 , 3.0 , 1.4 , 0.67 , 0.44
463 , 0.3 , 0.18 , 0.12 , 0.08 , 0.056
464 , 0.04 , 0.023, 0.015, 0.011, 0.01
473 dpos = energy - vxe[pos2++];
477 if (pos2 > nV) pos2 = nV;
480 // Differentiate between the sampling points
481 dnde = (vye[pos1] - vye[pos2]) / (vxe[pos2] - vxe[pos1]);