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46d29e70 1/**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
3 * *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
6 * *
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 **************************************************************************/
15
16/*
17$Log$
db30bf0f 18Revision 1.8 2001/01/26 19:56:57 hristov
19Major upgrade of AliRoot code
20
2ab0c725 21Revision 1.7 2000/12/20 13:00:45 cblume
22Modifications for the HP-compiler
23
d1b06c24 24Revision 1.6 2000/12/12 10:20:10 cblume
25Initialize fSepctrum = 0 in ctors
26
fa5e892a 27Revision 1.5 2000/10/15 23:40:01 cblume
28Remove AliTRDconst
29
0e9c2ad5 30Revision 1.4 2000/10/06 16:49:46 cblume
31Made Getters const
32
46d29e70 33Revision 1.3.2.1 2000/09/18 13:45:30 cblume
34New class AliTRDsim that simulates TR photons
35
36Revision 1.2 1999/09/29 09:24:35 fca
37Introduction of the Copyright and cvs Log
38
39*/
40
41///////////////////////////////////////////////////////////////////////////////
42// //
43// TRD simulation - multimodule (regular rad.) //
44// after: M. CASTELLANO et al., COMP. PHYS. COMM. 51 (1988) 431 //
45// + COMP. PHYS. COMM. 61 (1990) 395 //
46// //
47// 17.07.1998 - A.Andronic //
48// 08.12.1998 - simplified version //
49// 11.07.2000 - Adapted code to aliroot environment (C.Blume) //
50// //
51///////////////////////////////////////////////////////////////////////////////
52
53#include <stdlib.h>
54
0e9c2ad5 55#include <TH1.h>
56#include <TRandom.h>
57#include <TMath.h>
58#include <TParticle.h>
46d29e70 59
46d29e70 60#include "AliModule.h"
61
0e9c2ad5 62#include "AliTRDsim.h"
63
46d29e70 64ClassImp(AliTRDsim)
65
66//_____________________________________________________________________________
67AliTRDsim::AliTRDsim():TObject()
68{
69 //
70 // AliTRDsim default constructor
71 //
72
fa5e892a 73 fSpectrum = 0;
d1b06c24 74 fSigma = 0;
fa5e892a 75
46d29e70 76 Init();
77
78}
79
80//_____________________________________________________________________________
81AliTRDsim::AliTRDsim(AliModule *mod, Int_t foil, Int_t gap)
82{
83 //
84 // AliTRDsim constructor. Takes the material properties of the radiator
85 // foils and the gas in the gaps from AliModule <mod>.
86 // The default number of foils is 100 with a thickness of 20 mu. The
87 // thickness of the gaps is 500 mu.
88 //
89
90 Float_t aFoil, zFoil, rhoFoil;
91 Float_t aGap, zGap, rhoGap;
92 Float_t rad, abs;
93 Char_t name[21];
94
fa5e892a 95 fSpectrum = 0;
d1b06c24 96 fSigma = 0;
fa5e892a 97
46d29e70 98 Init();
99
100 mod->AliGetMaterial(foil,name,aFoil,zFoil,rhoFoil,rad,abs);
101 mod->AliGetMaterial(gap ,name,aGap ,zGap ,rhoGap ,rad,abs);
102
103 fFoilDens = rhoFoil;
104 fFoilA = aFoil;
105 fFoilZ = zFoil;
106 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
107
108 fGapDens = rhoGap;
109 fGapA = aGap;
110 fGapZ = zGap;
111 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
112
113}
114
115//_____________________________________________________________________________
116AliTRDsim::AliTRDsim(const AliTRDsim &s)
117{
118 //
119 // AliTRDsim copy constructor
120 //
121
122 ((AliTRDsim &) s).Copy(*this);
123
124}
125
126//_____________________________________________________________________________
127AliTRDsim::~AliTRDsim()
128{
129 //
130 // AliTRDsim destructor
131 //
132
133 if (fSpectrum) delete fSpectrum;
134 if (fSigma) delete fSigma;
135
136}
137
138//_____________________________________________________________________________
139AliTRDsim &AliTRDsim::operator=(const AliTRDsim &s)
140{
141 //
142 // Assignment operator
143 //
144
145 if (this != &s) ((AliTRDsim &) s).Copy(*this);
146 return *this;
147
148}
149
150//_____________________________________________________________________________
151void AliTRDsim::Copy(TObject &s)
152{
153 //
154 // Copy function
155 //
156
157 ((AliTRDsim &) s).fNFoils = fNFoils;
158 ((AliTRDsim &) s).fFoilThick = fFoilThick;
159 ((AliTRDsim &) s).fFoilDens = fFoilDens;
160 ((AliTRDsim &) s).fFoilOmega = fFoilOmega;
161 ((AliTRDsim &) s).fFoilZ = fFoilZ;
162 ((AliTRDsim &) s).fFoilA = fFoilA;
163 ((AliTRDsim &) s).fGapThick = fGapThick;
164 ((AliTRDsim &) s).fGapDens = fGapDens;
165 ((AliTRDsim &) s).fGapOmega = fGapOmega;
166 ((AliTRDsim &) s).fGapZ = fGapZ;
167 ((AliTRDsim &) s).fGapA = fGapA;
168 ((AliTRDsim &) s).fTemp = fTemp;
169 ((AliTRDsim &) s).fSpNBins = fSpNBins;
170 ((AliTRDsim &) s).fSpRange = fSpRange;
171 ((AliTRDsim &) s).fSpBinWidth = fSpBinWidth;
172 ((AliTRDsim &) s).fSpLower = fSpLower;
173 ((AliTRDsim &) s).fSpUpper = fSpUpper;
174
175 if (((AliTRDsim &) s).fSigma) delete ((AliTRDsim &) s).fSigma;
176 ((AliTRDsim &) s).fSigma = new Double_t[fSpNBins];
177 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
178 ((AliTRDsim &) s).fSigma[iBin] = fSigma[iBin];
179 }
180
181 fSpectrum->Copy(*((AliTRDsim &) s).fSpectrum);
182
183}
184
185//_____________________________________________________________________________
186void AliTRDsim::Init()
187{
188 //
189 // Initialization
db30bf0f 190 // The default radiator are 100 prolypropilene foils of 13 mu thickness
191 // with gaps of 60 mu filled with CO2.
46d29e70 192 //
193
194 fNFoils = 100;
195
db30bf0f 196 fFoilThick = 0.0013;
46d29e70 197 fFoilDens = 0.92;
198 fFoilZ = 5.28571;
199 fFoilA = 10.4286;
200 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
201
db30bf0f 202 fGapThick = 0.0060;
46d29e70 203 fGapDens = 0.001977;
204 fGapZ = 7.45455;
205 fGapA = 14.9091;
206 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
207
208 fTemp = 293.16;
209
210 fSpNBins = 200;
211 fSpRange = 100;
212 fSpBinWidth = fSpRange / fSpNBins;
213 fSpLower = 1.0 - 0.5 * fSpBinWidth;
214 fSpUpper = fSpLower + fSpRange;
215
216 if (fSpectrum) delete fSpectrum;
217 fSpectrum = new TH1D("TRspectrum","TR spectrum",fSpNBins,fSpLower,fSpUpper);
218
219 // Set the sigma values
220 SetSigma();
221
222}
223
224//_____________________________________________________________________________
225Int_t AliTRDsim::CreatePhotons(Int_t pdg, Float_t p
226 , Int_t &nPhoton, Float_t *ePhoton)
227{
228 //
229 // Create TRD photons for a charged particle of type <pdg> with the total
230 // momentum <p>.
231 // Number of produced TR photons: <nPhoton>
232 // Energies of the produced TR photons: <ePhoton>
233 //
234
235 // PDG codes
236 const Int_t kPdgEle = 11;
237 const Int_t kPdgMuon = 13;
238 const Int_t kPdgPion = 211;
239 const Int_t kPdgKaon = 321;
240
241 Float_t mass = 0;
242 switch (TMath::Abs(pdg)) {
243 case kPdgEle:
244 mass = 5.11e-4;
245 break;
246 case kPdgMuon:
247 mass = 0.10566;
248 break;
249 case kPdgPion:
250 mass = 0.13957;
251 break;
252 case kPdgKaon:
253 mass = 0.4937;
254 break;
255 default:
256 return 0;
257 break;
258 };
259
260 // Calculate gamma
261 Double_t gamma = TMath::Sqrt(p*p + mass*mass) / mass;
262
263 // Calculate the TR photons
264 return TrPhotons(gamma, nPhoton, ePhoton);
265
266}
267
268//_____________________________________________________________________________
269Int_t AliTRDsim::TrPhotons(Double_t gamma, Int_t &nPhoton, Float_t *ePhoton)
270{
271 //
272 // Produces TR photons.
273 //
274
275 const Double_t kAlpha = 0.0072973;
276 const Int_t kSumMax = 10;
277
278 Double_t kappa = fGapThick / fFoilThick;
279
280 fSpectrum->Reset();
281
282 // The TR spectrum
283 Double_t stemp = 0;
284 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
285
286 // keV -> eV
287 Double_t energyeV = (fSpBinWidth * iBin + 1.0) * 1e3;
288
289 Double_t csFoil = fFoilOmega / energyeV;
290 Double_t csGap = fGapOmega / energyeV;
291
292 Double_t rho1 = energyeV * fFoilThick * 1e4 * 2.5
293 * (1.0 / (gamma*gamma) + csFoil*csFoil);
294 Double_t rho2 = energyeV * fFoilThick * 1e4 * 2.5
295 * (1.0 / (gamma*gamma) + csGap *csGap);
296
297 // Calculate the sum
298 Double_t sum = 0;
299 for (Int_t iSum = 0; iSum < kSumMax; iSum++) {
300 Double_t tetan = (TMath::Pi() * 2.0 * (iSum+1) - (rho1 + kappa * rho2))
301 / (kappa + 1.0);
302 if (tetan < 0.0) tetan = 0.0;
303 Double_t aux = 1.0 / (rho1 + tetan) - 1.0 / (rho2 + tetan);
304 sum += tetan * (aux*aux) * (1.0 - TMath::Cos(rho1 + tetan));
305 }
306
307 // Absorbtion
308 Double_t conv = 1.0 - TMath::Exp(-fNFoils * fSigma[iBin]);
309
310 // eV -> keV
311 Float_t energykeV = energyeV * 0.001;
312
313 // dN / domega
314 Double_t wn = kAlpha * 4.0 / (fSigma[iBin] * (kappa + 1.0))
315 * conv * sum / energykeV;
316 fSpectrum->SetBinContent(iBin,wn);
317
318 stemp += wn;
319
320 }
321
322 // <nTR> (binsize corr.)
323 Float_t ntr = stemp * fSpBinWidth;
324 // Number of TR photons from Poisson distribution with mean <ntr>
325 nPhoton = gRandom->Poisson(ntr);
326 // Energy of the TR photons
327 for (Int_t iPhoton = 0; iPhoton < nPhoton; iPhoton++) {
328 ePhoton[iPhoton] = fSpectrum->GetRandom();
329 }
330
331 return 1;
332
333}
334
335//_____________________________________________________________________________
336void AliTRDsim::SetSigma()
337{
338 //
339 // Sets the absorbtion crosssection for the energies of the TR spectrum
340 //
341
342 if (fSigma) delete fSigma;
343 fSigma = new Double_t[fSpNBins];
344 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
345 Double_t energykeV = iBin * fSpBinWidth + 1.0;
346 fSigma[iBin] = Sigma(energykeV);
347 //printf("SetSigma(): iBin = %d fSigma %g\n",iBin,fSigma[iBin]);
348 }
349
350}
351
352//_____________________________________________________________________________
353Double_t AliTRDsim::Sigma(Double_t energykeV)
354{
355 //
356 // Calculates the absorbtion crosssection for a one-foil-one-gap-radiator
357 //
358
359 // Gas at 0 C
360 const Double_t kTemp0 = 273.16;
361
362 // keV -> MeV
363 Double_t energyMeV = energykeV * 0.001;
364 if (energyMeV >= 0.001) {
365 return(GetMuPo(energyMeV) * fFoilDens * fFoilThick +
366 GetMuCO(energyMeV) * fGapDens * fGapThick * fTemp/kTemp0);
367 }
368 else {
369 return 1e6;
370 }
371
372}
373
374//_____________________________________________________________________________
375Double_t AliTRDsim::GetMuPo(Double_t energyMeV)
376{
377 //
378 // Returns the photon absorbtion cross section for polypropylene
379 //
380
381 const Int_t kN = 36;
382
383 Double_t mu[kN] = { 1.894E+03, 5.999E+02, 2.593E+02
384 , 7.743E+01, 3.242E+01, 1.643E+01
385 , 9.432E+00, 3.975E+00, 2.088E+00
386 , 7.452E-01, 4.315E-01, 2.706E-01
387 , 2.275E-01, 2.084E-01, 1.970E-01
388 , 1.823E-01, 1.719E-01, 1.534E-01
389 , 1.402E-01, 1.217E-01, 1.089E-01
390 , 9.947E-02, 9.198E-02, 8.078E-02
391 , 7.262E-02, 6.495E-02, 5.910E-02
392 , 5.064E-02, 4.045E-02, 3.444E-02
393 , 3.045E-02, 2.760E-02, 2.383E-02
394 , 2.145E-02, 1.819E-02, 1.658E-02 };
395
396 Double_t en[kN] = { 1.000E-03, 1.500E-03, 2.000E-03
397 , 3.000E-03, 4.000E-03, 5.000E-03
398 , 6.000E-03, 8.000E-03, 1.000E-02
399 , 1.500E-02, 2.000E-02, 3.000E-02
400 , 4.000E-02, 5.000E-02, 6.000E-02
401 , 8.000E-02, 1.000E-01, 1.500E-01
402 , 2.000E-01, 3.000E-01, 4.000E-01
403 , 5.000E-01, 6.000E-01, 8.000E-01
404 , 1.000E+00, 1.250E+00, 1.500E+00
405 , 2.000E+00, 3.000E+00, 4.000E+00
406 , 5.000E+00, 6.000E+00, 8.000E+00
407 , 1.000E+01, 1.500E+01, 2.000E+01 };
408
409 return Interpolate(energyMeV,en,mu,kN);
410
411}
412
413//_____________________________________________________________________________
414Double_t AliTRDsim::GetMuCO(Double_t energyMeV)
415{
416 //
417 // Returns the photon absorbtion cross section for CO2
418 //
419
420 const Int_t kN = 36;
421
422 Double_t mu[kN] = { 0.39383E+04, 0.13166E+04, 0.58750E+03
423 , 0.18240E+03, 0.77996E+02, 0.40024E+02
424 , 0.23116E+02, 0.96997E+01, 0.49726E+01
425 , 0.15543E+01, 0.74915E+00, 0.34442E+00
426 , 0.24440E+00, 0.20589E+00, 0.18632E+00
427 , 0.16578E+00, 0.15394E+00, 0.13558E+00
428 , 0.12336E+00, 0.10678E+00, 0.95510E-01
429 , 0.87165E-01, 0.80587E-01, 0.70769E-01
430 , 0.63626E-01, 0.56894E-01, 0.51782E-01
431 , 0.44499E-01, 0.35839E-01, 0.30825E-01
432 , 0.27555E-01, 0.25269E-01, 0.22311E-01
433 , 0.20516E-01, 0.18184E-01, 0.17152E-01 };
434
435 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
436 , 0.30000E-02, 0.40000E-02, 0.50000E-02
437 , 0.60000E-02, 0.80000E-02, 0.10000E-01
438 , 0.15000E-01, 0.20000E-01, 0.30000E-01
439 , 0.40000E-01, 0.50000E-01, 0.60000E-01
440 , 0.80000E-01, 0.10000E+00, 0.15000E+00
441 , 0.20000E+00, 0.30000E+00, 0.40000E+00
442 , 0.50000E+00, 0.60000E+00, 0.80000E+00
443 , 0.10000E+01, 0.12500E+01, 0.15000E+01
444 , 0.20000E+01, 0.30000E+01, 0.40000E+01
445 , 0.50000E+01, 0.60000E+01, 0.80000E+01
446 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
447
448 return Interpolate(energyMeV,en,mu,kN);
449
450}
451
452//_____________________________________________________________________________
453Double_t AliTRDsim::GetMuXe(Double_t energyMeV)
454{
455 //
456 // Returns the photon absorbtion cross section for xenon
457 //
458
459 const Int_t kN = 48;
460
461 Double_t mu[kN] = { 9.413E+03, 8.151E+03, 7.035E+03
462 , 7.338E+03, 4.085E+03, 2.088E+03
463 , 7.780E+02, 3.787E+02, 2.408E+02
464 , 6.941E+02, 6.392E+02, 6.044E+02
465 , 8.181E+02, 7.579E+02, 6.991E+02
466 , 8.064E+02, 6.376E+02, 3.032E+02
467 , 1.690E+02, 5.743E+01, 2.652E+01
468 , 8.930E+00, 6.129E+00, 3.316E+01
469 , 2.270E+01, 1.272E+01, 7.825E+00
470 , 3.633E+00, 2.011E+00, 7.202E-01
471 , 3.760E-01, 1.797E-01, 1.223E-01
472 , 9.699E-02, 8.281E-02, 6.696E-02
473 , 5.785E-02, 5.054E-02, 4.594E-02
474 , 4.078E-02, 3.681E-02, 3.577E-02
475 , 3.583E-02, 3.634E-02, 3.797E-02
476 , 3.987E-02, 4.445E-02, 4.815E-02 };
477
478 Double_t en[kN] = { 1.00000E-03, 1.07191E-03, 1.14900E-03
479 , 1.14900E-03, 1.50000E-03, 2.00000E-03
480 , 3.00000E-03, 4.00000E-03, 4.78220E-03
481 , 4.78220E-03, 5.00000E-03, 5.10370E-03
482 , 5.10370E-03, 5.27536E-03, 5.45280E-03
483 , 5.45280E-03, 6.00000E-03, 8.00000E-03
484 , 1.00000E-02, 1.50000E-02, 2.00000E-02
485 , 3.00000E-02, 3.45614E-02, 3.45614E-02
486 , 4.00000E-02, 5.00000E-02, 6.00000E-02
487 , 8.00000E-02, 1.00000E-01, 1.50000E-01
488 , 2.00000E-01, 3.00000E-01, 4.00000E-01
489 , 5.00000E-01, 6.00000E-01, 8.00000E-01
490 , 1.00000E+00, 1.25000E+00, 1.50000E+00
491 , 2.00000E+00, 3.00000E+00, 4.00000E+00
492 , 5.00000E+00, 6.00000E+00, 8.00000E+00
493 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
494
495 return Interpolate(energyMeV,en,mu,kN);
496
497}
498
499//_____________________________________________________________________________
500Double_t AliTRDsim::GetMuBu(Double_t energyMeV)
501{
502 //
503 // Returns the photon absorbtion cross section for isobutane
504 //
505
506 const Int_t kN = 36;
507
508 Double_t mu[kN] = { 0.38846E+03, 0.12291E+03, 0.53225E+02
509 , 0.16091E+02, 0.69114E+01, 0.36541E+01
510 , 0.22282E+01, 0.11149E+01, 0.72887E+00
511 , 0.45053E+00, 0.38167E+00, 0.33920E+00
512 , 0.32155E+00, 0.30949E+00, 0.29960E+00
513 , 0.28317E+00, 0.26937E+00, 0.24228E+00
514 , 0.22190E+00, 0.19289E+00, 0.17288E+00
515 , 0.15789E+00, 0.14602E+00, 0.12829E+00
516 , 0.11533E+00, 0.10310E+00, 0.93790E-01
517 , 0.80117E-01, 0.63330E-01, 0.53229E-01
518 , 0.46390E-01, 0.41425E-01, 0.34668E-01
519 , 0.30267E-01, 0.23910E-01, 0.20509E-01 };
520
521 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
522 , 0.30000E-02, 0.40000E-02, 0.50000E-02
523 , 0.60000E-02, 0.80000E-02, 0.10000E-01
524 , 0.15000E-01, 0.20000E-01, 0.30000E-01
525 , 0.40000E-01, 0.50000E-01, 0.60000E-01
526 , 0.80000E-01, 0.10000E+00, 0.15000E+00
527 , 0.20000E+00, 0.30000E+00, 0.40000E+00
528 , 0.50000E+00, 0.60000E+00, 0.80000E+00
529 , 0.10000E+01, 0.12500E+01, 0.15000E+01
530 , 0.20000E+01, 0.30000E+01, 0.40000E+01
531 , 0.50000E+01, 0.60000E+01, 0.80000E+01
532 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
533
534 return Interpolate(energyMeV,en,mu,kN);
535
536}
537
538//_____________________________________________________________________________
539Double_t AliTRDsim::GetMuMy(Double_t energyMeV)
540{
541 //
542 // Returns the photon absorbtion cross section for mylar
543 //
544
545 const Int_t kN = 36;
546
547 Double_t mu[kN] = { 2.911E+03, 9.536E+02, 4.206E+02
548 , 1.288E+02, 5.466E+01, 2.792E+01
549 , 1.608E+01, 6.750E+00, 3.481E+00
550 , 1.132E+00, 5.798E-01, 3.009E-01
551 , 2.304E-01, 2.020E-01, 1.868E-01
552 , 1.695E-01, 1.586E-01, 1.406E-01
553 , 1.282E-01, 1.111E-01, 9.947E-02
554 , 9.079E-02, 8.395E-02, 7.372E-02
555 , 6.628E-02, 5.927E-02, 5.395E-02
556 , 4.630E-02, 3.715E-02, 3.181E-02
557 , 2.829E-02, 2.582E-02, 2.257E-02
558 , 2.057E-02, 1.789E-02, 1.664E-02 };
559
560 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
561 , 3.00000E-03, 4.00000E-03, 5.00000E-03
562 , 6.00000E-03, 8.00000E-03, 1.00000E-02
563 , 1.50000E-02, 2.00000E-02, 3.00000E-02
564 , 4.00000E-02, 5.00000E-02, 6.00000E-02
565 , 8.00000E-02, 1.00000E-01, 1.50000E-01
566 , 2.00000E-01, 3.00000E-01, 4.00000E-01
567 , 5.00000E-01, 6.00000E-01, 8.00000E-01
568 , 1.00000E+00, 1.25000E+00, 1.50000E+00
569 , 2.00000E+00, 3.00000E+00, 4.00000E+00
570 , 5.00000E+00, 6.00000E+00, 8.00000E+00
571 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
572
573 return Interpolate(energyMeV,en,mu,kN);
574
575}
576
577//_____________________________________________________________________________
578Double_t AliTRDsim::GetMuN2(Double_t energyMeV)
579{
580 //
581 // Returns the photon absorbtion cross section for nitrogen
582 //
583
584 const Int_t kN = 36;
585
586 Double_t mu[kN] = { 3.311E+03, 1.083E+03, 4.769E+02
587 , 1.456E+02, 6.166E+01, 3.144E+01
588 , 1.809E+01, 7.562E+00, 3.879E+00
589 , 1.236E+00, 6.178E-01, 3.066E-01
590 , 2.288E-01, 1.980E-01, 1.817E-01
591 , 1.639E-01, 1.529E-01, 1.353E-01
592 , 1.233E-01, 1.068E-01, 9.557E-02
593 , 8.719E-02, 8.063E-02, 7.081E-02
594 , 6.364E-02, 5.693E-02, 5.180E-02
595 , 4.450E-02, 3.579E-02, 3.073E-02
596 , 2.742E-02, 2.511E-02, 2.209E-02
597 , 2.024E-02, 1.782E-02, 1.673E-02 };
598
599 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
600 , 3.00000E-03, 4.00000E-03, 5.00000E-03
601 , 6.00000E-03, 8.00000E-03, 1.00000E-02
602 , 1.50000E-02, 2.00000E-02, 3.00000E-02
603 , 4.00000E-02, 5.00000E-02, 6.00000E-02
604 , 8.00000E-02, 1.00000E-01, 1.50000E-01
605 , 2.00000E-01, 3.00000E-01, 4.00000E-01
606 , 5.00000E-01, 6.00000E-01, 8.00000E-01
607 , 1.00000E+00, 1.25000E+00, 1.50000E+00
608 , 2.00000E+00, 3.00000E+00, 4.00000E+00
609 , 5.00000E+00, 6.00000E+00, 8.00000E+00
610 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
611
612 return Interpolate(energyMeV,en,mu,kN);
613
614}
615
616//_____________________________________________________________________________
617Double_t AliTRDsim::GetMuO2(Double_t energyMeV)
618{
619 //
620 // Returns the photon absorbtion cross section for oxygen
621 //
622
623 const Int_t kN = 36;
624
625 Double_t mu[kN] = { 4.590E+03, 1.549E+03, 6.949E+02
626 , 2.171E+02, 9.315E+01, 4.790E+01
627 , 2.770E+01, 1.163E+01, 5.952E+00
628 , 1.836E+00, 8.651E-01, 3.779E-01
629 , 2.585E-01, 2.132E-01, 1.907E-01
630 , 1.678E-01, 1.551E-01, 1.361E-01
631 , 1.237E-01, 1.070E-01, 9.566E-02
632 , 8.729E-02, 8.070E-02, 7.087E-02
633 , 6.372E-02, 5.697E-02, 5.185E-02
634 , 4.459E-02, 3.597E-02, 3.100E-02
635 , 2.777E-02, 2.552E-02, 2.263E-02
636 , 2.089E-02, 1.866E-02, 1.770E-02 };
637
638 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
639 , 3.00000E-03, 4.00000E-03, 5.00000E-03
640 , 6.00000E-03, 8.00000E-03, 1.00000E-02
641 , 1.50000E-02, 2.00000E-02, 3.00000E-02
642 , 4.00000E-02, 5.00000E-02, 6.00000E-02
643 , 8.00000E-02, 1.00000E-01, 1.50000E-01
644 , 2.00000E-01, 3.00000E-01, 4.00000E-01
645 , 5.00000E-01, 6.00000E-01, 8.00000E-01
646 , 1.00000E+00, 1.25000E+00, 1.50000E+00
647 , 2.00000E+00, 3.00000E+00, 4.00000E+00
648 , 5.00000E+00, 6.00000E+00, 8.00000E+00
649 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
650
651 return Interpolate(energyMeV,en,mu,kN);
652
653}
654
655//_____________________________________________________________________________
656Double_t AliTRDsim::GetMuHe(Double_t energyMeV)
657{
658 //
659 // Returns the photon absorbtion cross section for helium
660 //
661
662 const Int_t kN = 36;
663
664 Double_t mu[kN] = { 6.084E+01, 1.676E+01, 6.863E+00
665 , 2.007E+00, 9.329E-01, 5.766E-01
666 , 4.195E-01, 2.933E-01, 2.476E-01
667 , 2.092E-01, 1.960E-01, 1.838E-01
668 , 1.763E-01, 1.703E-01, 1.651E-01
669 , 1.562E-01, 1.486E-01, 1.336E-01
670 , 1.224E-01, 1.064E-01, 9.535E-02
671 , 8.707E-02, 8.054E-02, 7.076E-02
672 , 6.362E-02, 5.688E-02, 5.173E-02
673 , 4.422E-02, 3.503E-02, 2.949E-02
674 , 2.577E-02, 2.307E-02, 1.940E-02
675 , 1.703E-02, 1.363E-02, 1.183E-02 };
676
677 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
678 , 3.00000E-03, 4.00000E-03, 5.00000E-03
679 , 6.00000E-03, 8.00000E-03, 1.00000E-02
680 , 1.50000E-02, 2.00000E-02, 3.00000E-02
681 , 4.00000E-02, 5.00000E-02, 6.00000E-02
682 , 8.00000E-02, 1.00000E-01, 1.50000E-01
683 , 2.00000E-01, 3.00000E-01, 4.00000E-01
684 , 5.00000E-01, 6.00000E-01, 8.00000E-01
685 , 1.00000E+00, 1.25000E+00, 1.50000E+00
686 , 2.00000E+00, 3.00000E+00, 4.00000E+00
687 , 5.00000E+00, 6.00000E+00, 8.00000E+00
688 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
689
690 return Interpolate(energyMeV,en,mu,kN);
691
692}
693
694//_____________________________________________________________________________
695Double_t AliTRDsim::Interpolate(Double_t energyMeV
696 , Double_t *en, Double_t *mu, Int_t n)
697{
698 //
699 // Interpolates the photon absorbtion cross section
700 // for a given energy <energyMeV>.
701 //
702
703 Double_t de = 0;
704 Int_t index = 0;
705 Int_t istat = Locate(en,n,energyMeV,index,de);
706 if (istat == 0) {
707 return (mu[index] - de * (mu[index] - mu[index+1])
708 / (en[index+1] - en[index] ));
709 }
710 else {
711 return 0.0;
712 }
713
714}
715
716//_____________________________________________________________________________
717Int_t AliTRDsim::Locate(Double_t *xv, Int_t n, Double_t xval
718 , Int_t &kl, Double_t &dx)
719{
720 //
721 // Locates a point (xval) in a 1-dim grid (xv(n))
722 //
723
724 if (xval >= xv[n-1]) return 1;
725 if (xval < xv[0]) return -1;
726
727 Int_t km;
728 Int_t kh = n - 1;
729
730 kl = 0;
731 while (kh - kl > 1) {
732 if (xval < xv[km = (kl+kh)/2]) kh = km;
733 else kl = km;
734 }
735 if (xval < xv[kl] || xval > xv[kl+1] || kl >= n-1) {
736 printf("Locate failed xv[%d] %f xval %f xv[%d] %f!!!\n"
737 ,kl,xv[kl],xval,kl+1,xv[kl+1]);
738 exit(1);
739 }
740
741 dx = xval - xv[kl];
742
743 return 0;
744
745}