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[u/mrichter/AliRoot.git] / TRD / AliTRDsim.cxx
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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$Log$
5567246e 18Revision 1.9 2001/05/21 16:45:47 hristov
19Last minute changes (C.Blume)
20
db30bf0f 21Revision 1.8 2001/01/26 19:56:57 hristov
22Major upgrade of AliRoot code
23
2ab0c725 24Revision 1.7 2000/12/20 13:00:45 cblume
25Modifications for the HP-compiler
26
d1b06c24 27Revision 1.6 2000/12/12 10:20:10 cblume
28Initialize fSepctrum = 0 in ctors
29
fa5e892a 30Revision 1.5 2000/10/15 23:40:01 cblume
31Remove AliTRDconst
32
0e9c2ad5 33Revision 1.4 2000/10/06 16:49:46 cblume
34Made Getters const
35
46d29e70 36Revision 1.3.2.1 2000/09/18 13:45:30 cblume
37New class AliTRDsim that simulates TR photons
38
39Revision 1.2 1999/09/29 09:24:35 fca
40Introduction of the Copyright and cvs Log
41
42*/
43
44///////////////////////////////////////////////////////////////////////////////
45// //
46// TRD simulation - multimodule (regular rad.) //
47// after: M. CASTELLANO et al., COMP. PHYS. COMM. 51 (1988) 431 //
48// + COMP. PHYS. COMM. 61 (1990) 395 //
49// //
50// 17.07.1998 - A.Andronic //
51// 08.12.1998 - simplified version //
52// 11.07.2000 - Adapted code to aliroot environment (C.Blume) //
53// //
54///////////////////////////////////////////////////////////////////////////////
55
56#include <stdlib.h>
57
0e9c2ad5 58#include <TH1.h>
59#include <TRandom.h>
60#include <TMath.h>
61#include <TParticle.h>
46d29e70 62
46d29e70 63#include "AliModule.h"
64
0e9c2ad5 65#include "AliTRDsim.h"
66
46d29e70 67ClassImp(AliTRDsim)
68
69//_____________________________________________________________________________
70AliTRDsim::AliTRDsim():TObject()
71{
72 //
73 // AliTRDsim default constructor
74 //
75
fa5e892a 76 fSpectrum = 0;
d1b06c24 77 fSigma = 0;
fa5e892a 78
46d29e70 79 Init();
80
81}
82
83//_____________________________________________________________________________
84AliTRDsim::AliTRDsim(AliModule *mod, Int_t foil, Int_t gap)
85{
86 //
87 // AliTRDsim constructor. Takes the material properties of the radiator
88 // foils and the gas in the gaps from AliModule <mod>.
89 // The default number of foils is 100 with a thickness of 20 mu. The
90 // thickness of the gaps is 500 mu.
91 //
92
93 Float_t aFoil, zFoil, rhoFoil;
94 Float_t aGap, zGap, rhoGap;
95 Float_t rad, abs;
96 Char_t name[21];
97
fa5e892a 98 fSpectrum = 0;
d1b06c24 99 fSigma = 0;
fa5e892a 100
46d29e70 101 Init();
102
103 mod->AliGetMaterial(foil,name,aFoil,zFoil,rhoFoil,rad,abs);
104 mod->AliGetMaterial(gap ,name,aGap ,zGap ,rhoGap ,rad,abs);
105
106 fFoilDens = rhoFoil;
107 fFoilA = aFoil;
108 fFoilZ = zFoil;
109 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
110
111 fGapDens = rhoGap;
112 fGapA = aGap;
113 fGapZ = zGap;
114 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
115
116}
117
118//_____________________________________________________________________________
119AliTRDsim::AliTRDsim(const AliTRDsim &s)
120{
121 //
122 // AliTRDsim copy constructor
123 //
124
125 ((AliTRDsim &) s).Copy(*this);
126
127}
128
129//_____________________________________________________________________________
130AliTRDsim::~AliTRDsim()
131{
132 //
133 // AliTRDsim destructor
134 //
135
5567246e 136 // if (fSpectrum) delete fSpectrum;
137 if (fSigma) delete [] fSigma;
46d29e70 138
139}
140
141//_____________________________________________________________________________
142AliTRDsim &AliTRDsim::operator=(const AliTRDsim &s)
143{
144 //
145 // Assignment operator
146 //
147
148 if (this != &s) ((AliTRDsim &) s).Copy(*this);
149 return *this;
150
151}
152
153//_____________________________________________________________________________
154void AliTRDsim::Copy(TObject &s)
155{
156 //
157 // Copy function
158 //
159
160 ((AliTRDsim &) s).fNFoils = fNFoils;
161 ((AliTRDsim &) s).fFoilThick = fFoilThick;
162 ((AliTRDsim &) s).fFoilDens = fFoilDens;
163 ((AliTRDsim &) s).fFoilOmega = fFoilOmega;
164 ((AliTRDsim &) s).fFoilZ = fFoilZ;
165 ((AliTRDsim &) s).fFoilA = fFoilA;
166 ((AliTRDsim &) s).fGapThick = fGapThick;
167 ((AliTRDsim &) s).fGapDens = fGapDens;
168 ((AliTRDsim &) s).fGapOmega = fGapOmega;
169 ((AliTRDsim &) s).fGapZ = fGapZ;
170 ((AliTRDsim &) s).fGapA = fGapA;
171 ((AliTRDsim &) s).fTemp = fTemp;
172 ((AliTRDsim &) s).fSpNBins = fSpNBins;
173 ((AliTRDsim &) s).fSpRange = fSpRange;
174 ((AliTRDsim &) s).fSpBinWidth = fSpBinWidth;
175 ((AliTRDsim &) s).fSpLower = fSpLower;
176 ((AliTRDsim &) s).fSpUpper = fSpUpper;
177
5567246e 178 if (((AliTRDsim &) s).fSigma) delete [] ((AliTRDsim &) s).fSigma;
46d29e70 179 ((AliTRDsim &) s).fSigma = new Double_t[fSpNBins];
180 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
181 ((AliTRDsim &) s).fSigma[iBin] = fSigma[iBin];
182 }
183
184 fSpectrum->Copy(*((AliTRDsim &) s).fSpectrum);
185
186}
187
188//_____________________________________________________________________________
189void AliTRDsim::Init()
190{
191 //
192 // Initialization
db30bf0f 193 // The default radiator are 100 prolypropilene foils of 13 mu thickness
194 // with gaps of 60 mu filled with CO2.
46d29e70 195 //
196
197 fNFoils = 100;
198
db30bf0f 199 fFoilThick = 0.0013;
46d29e70 200 fFoilDens = 0.92;
201 fFoilZ = 5.28571;
202 fFoilA = 10.4286;
203 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
204
db30bf0f 205 fGapThick = 0.0060;
46d29e70 206 fGapDens = 0.001977;
207 fGapZ = 7.45455;
208 fGapA = 14.9091;
209 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
210
211 fTemp = 293.16;
212
213 fSpNBins = 200;
214 fSpRange = 100;
215 fSpBinWidth = fSpRange / fSpNBins;
216 fSpLower = 1.0 - 0.5 * fSpBinWidth;
217 fSpUpper = fSpLower + fSpRange;
218
219 if (fSpectrum) delete fSpectrum;
220 fSpectrum = new TH1D("TRspectrum","TR spectrum",fSpNBins,fSpLower,fSpUpper);
221
222 // Set the sigma values
223 SetSigma();
224
225}
226
227//_____________________________________________________________________________
228Int_t AliTRDsim::CreatePhotons(Int_t pdg, Float_t p
229 , Int_t &nPhoton, Float_t *ePhoton)
230{
231 //
232 // Create TRD photons for a charged particle of type <pdg> with the total
233 // momentum <p>.
234 // Number of produced TR photons: <nPhoton>
235 // Energies of the produced TR photons: <ePhoton>
236 //
237
238 // PDG codes
239 const Int_t kPdgEle = 11;
240 const Int_t kPdgMuon = 13;
241 const Int_t kPdgPion = 211;
242 const Int_t kPdgKaon = 321;
243
244 Float_t mass = 0;
245 switch (TMath::Abs(pdg)) {
246 case kPdgEle:
247 mass = 5.11e-4;
248 break;
249 case kPdgMuon:
250 mass = 0.10566;
251 break;
252 case kPdgPion:
253 mass = 0.13957;
254 break;
255 case kPdgKaon:
256 mass = 0.4937;
257 break;
258 default:
259 return 0;
260 break;
261 };
262
263 // Calculate gamma
264 Double_t gamma = TMath::Sqrt(p*p + mass*mass) / mass;
265
266 // Calculate the TR photons
267 return TrPhotons(gamma, nPhoton, ePhoton);
268
269}
270
271//_____________________________________________________________________________
272Int_t AliTRDsim::TrPhotons(Double_t gamma, Int_t &nPhoton, Float_t *ePhoton)
273{
274 //
275 // Produces TR photons.
276 //
277
278 const Double_t kAlpha = 0.0072973;
279 const Int_t kSumMax = 10;
280
281 Double_t kappa = fGapThick / fFoilThick;
282
283 fSpectrum->Reset();
284
285 // The TR spectrum
286 Double_t stemp = 0;
287 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
288
289 // keV -> eV
290 Double_t energyeV = (fSpBinWidth * iBin + 1.0) * 1e3;
291
292 Double_t csFoil = fFoilOmega / energyeV;
293 Double_t csGap = fGapOmega / energyeV;
294
295 Double_t rho1 = energyeV * fFoilThick * 1e4 * 2.5
296 * (1.0 / (gamma*gamma) + csFoil*csFoil);
297 Double_t rho2 = energyeV * fFoilThick * 1e4 * 2.5
298 * (1.0 / (gamma*gamma) + csGap *csGap);
299
300 // Calculate the sum
301 Double_t sum = 0;
302 for (Int_t iSum = 0; iSum < kSumMax; iSum++) {
303 Double_t tetan = (TMath::Pi() * 2.0 * (iSum+1) - (rho1 + kappa * rho2))
304 / (kappa + 1.0);
305 if (tetan < 0.0) tetan = 0.0;
306 Double_t aux = 1.0 / (rho1 + tetan) - 1.0 / (rho2 + tetan);
307 sum += tetan * (aux*aux) * (1.0 - TMath::Cos(rho1 + tetan));
308 }
309
310 // Absorbtion
311 Double_t conv = 1.0 - TMath::Exp(-fNFoils * fSigma[iBin]);
312
313 // eV -> keV
314 Float_t energykeV = energyeV * 0.001;
315
316 // dN / domega
317 Double_t wn = kAlpha * 4.0 / (fSigma[iBin] * (kappa + 1.0))
318 * conv * sum / energykeV;
319 fSpectrum->SetBinContent(iBin,wn);
320
321 stemp += wn;
322
323 }
324
325 // <nTR> (binsize corr.)
326 Float_t ntr = stemp * fSpBinWidth;
327 // Number of TR photons from Poisson distribution with mean <ntr>
328 nPhoton = gRandom->Poisson(ntr);
329 // Energy of the TR photons
330 for (Int_t iPhoton = 0; iPhoton < nPhoton; iPhoton++) {
331 ePhoton[iPhoton] = fSpectrum->GetRandom();
332 }
333
334 return 1;
335
336}
337
338//_____________________________________________________________________________
339void AliTRDsim::SetSigma()
340{
341 //
342 // Sets the absorbtion crosssection for the energies of the TR spectrum
343 //
344
5567246e 345 if (fSigma) delete [] fSigma;
46d29e70 346 fSigma = new Double_t[fSpNBins];
347 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
348 Double_t energykeV = iBin * fSpBinWidth + 1.0;
349 fSigma[iBin] = Sigma(energykeV);
350 //printf("SetSigma(): iBin = %d fSigma %g\n",iBin,fSigma[iBin]);
351 }
352
353}
354
355//_____________________________________________________________________________
356Double_t AliTRDsim::Sigma(Double_t energykeV)
357{
358 //
359 // Calculates the absorbtion crosssection for a one-foil-one-gap-radiator
360 //
361
362 // Gas at 0 C
363 const Double_t kTemp0 = 273.16;
364
365 // keV -> MeV
366 Double_t energyMeV = energykeV * 0.001;
367 if (energyMeV >= 0.001) {
368 return(GetMuPo(energyMeV) * fFoilDens * fFoilThick +
369 GetMuCO(energyMeV) * fGapDens * fGapThick * fTemp/kTemp0);
370 }
371 else {
372 return 1e6;
373 }
374
375}
376
377//_____________________________________________________________________________
378Double_t AliTRDsim::GetMuPo(Double_t energyMeV)
379{
380 //
381 // Returns the photon absorbtion cross section for polypropylene
382 //
383
384 const Int_t kN = 36;
385
386 Double_t mu[kN] = { 1.894E+03, 5.999E+02, 2.593E+02
387 , 7.743E+01, 3.242E+01, 1.643E+01
388 , 9.432E+00, 3.975E+00, 2.088E+00
389 , 7.452E-01, 4.315E-01, 2.706E-01
390 , 2.275E-01, 2.084E-01, 1.970E-01
391 , 1.823E-01, 1.719E-01, 1.534E-01
392 , 1.402E-01, 1.217E-01, 1.089E-01
393 , 9.947E-02, 9.198E-02, 8.078E-02
394 , 7.262E-02, 6.495E-02, 5.910E-02
395 , 5.064E-02, 4.045E-02, 3.444E-02
396 , 3.045E-02, 2.760E-02, 2.383E-02
397 , 2.145E-02, 1.819E-02, 1.658E-02 };
398
399 Double_t en[kN] = { 1.000E-03, 1.500E-03, 2.000E-03
400 , 3.000E-03, 4.000E-03, 5.000E-03
401 , 6.000E-03, 8.000E-03, 1.000E-02
402 , 1.500E-02, 2.000E-02, 3.000E-02
403 , 4.000E-02, 5.000E-02, 6.000E-02
404 , 8.000E-02, 1.000E-01, 1.500E-01
405 , 2.000E-01, 3.000E-01, 4.000E-01
406 , 5.000E-01, 6.000E-01, 8.000E-01
407 , 1.000E+00, 1.250E+00, 1.500E+00
408 , 2.000E+00, 3.000E+00, 4.000E+00
409 , 5.000E+00, 6.000E+00, 8.000E+00
410 , 1.000E+01, 1.500E+01, 2.000E+01 };
411
412 return Interpolate(energyMeV,en,mu,kN);
413
414}
415
416//_____________________________________________________________________________
417Double_t AliTRDsim::GetMuCO(Double_t energyMeV)
418{
419 //
420 // Returns the photon absorbtion cross section for CO2
421 //
422
423 const Int_t kN = 36;
424
425 Double_t mu[kN] = { 0.39383E+04, 0.13166E+04, 0.58750E+03
426 , 0.18240E+03, 0.77996E+02, 0.40024E+02
427 , 0.23116E+02, 0.96997E+01, 0.49726E+01
428 , 0.15543E+01, 0.74915E+00, 0.34442E+00
429 , 0.24440E+00, 0.20589E+00, 0.18632E+00
430 , 0.16578E+00, 0.15394E+00, 0.13558E+00
431 , 0.12336E+00, 0.10678E+00, 0.95510E-01
432 , 0.87165E-01, 0.80587E-01, 0.70769E-01
433 , 0.63626E-01, 0.56894E-01, 0.51782E-01
434 , 0.44499E-01, 0.35839E-01, 0.30825E-01
435 , 0.27555E-01, 0.25269E-01, 0.22311E-01
436 , 0.20516E-01, 0.18184E-01, 0.17152E-01 };
437
438 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
439 , 0.30000E-02, 0.40000E-02, 0.50000E-02
440 , 0.60000E-02, 0.80000E-02, 0.10000E-01
441 , 0.15000E-01, 0.20000E-01, 0.30000E-01
442 , 0.40000E-01, 0.50000E-01, 0.60000E-01
443 , 0.80000E-01, 0.10000E+00, 0.15000E+00
444 , 0.20000E+00, 0.30000E+00, 0.40000E+00
445 , 0.50000E+00, 0.60000E+00, 0.80000E+00
446 , 0.10000E+01, 0.12500E+01, 0.15000E+01
447 , 0.20000E+01, 0.30000E+01, 0.40000E+01
448 , 0.50000E+01, 0.60000E+01, 0.80000E+01
449 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
450
451 return Interpolate(energyMeV,en,mu,kN);
452
453}
454
455//_____________________________________________________________________________
456Double_t AliTRDsim::GetMuXe(Double_t energyMeV)
457{
458 //
459 // Returns the photon absorbtion cross section for xenon
460 //
461
462 const Int_t kN = 48;
463
464 Double_t mu[kN] = { 9.413E+03, 8.151E+03, 7.035E+03
465 , 7.338E+03, 4.085E+03, 2.088E+03
466 , 7.780E+02, 3.787E+02, 2.408E+02
467 , 6.941E+02, 6.392E+02, 6.044E+02
468 , 8.181E+02, 7.579E+02, 6.991E+02
469 , 8.064E+02, 6.376E+02, 3.032E+02
470 , 1.690E+02, 5.743E+01, 2.652E+01
471 , 8.930E+00, 6.129E+00, 3.316E+01
472 , 2.270E+01, 1.272E+01, 7.825E+00
473 , 3.633E+00, 2.011E+00, 7.202E-01
474 , 3.760E-01, 1.797E-01, 1.223E-01
475 , 9.699E-02, 8.281E-02, 6.696E-02
476 , 5.785E-02, 5.054E-02, 4.594E-02
477 , 4.078E-02, 3.681E-02, 3.577E-02
478 , 3.583E-02, 3.634E-02, 3.797E-02
479 , 3.987E-02, 4.445E-02, 4.815E-02 };
480
481 Double_t en[kN] = { 1.00000E-03, 1.07191E-03, 1.14900E-03
482 , 1.14900E-03, 1.50000E-03, 2.00000E-03
483 , 3.00000E-03, 4.00000E-03, 4.78220E-03
484 , 4.78220E-03, 5.00000E-03, 5.10370E-03
485 , 5.10370E-03, 5.27536E-03, 5.45280E-03
486 , 5.45280E-03, 6.00000E-03, 8.00000E-03
487 , 1.00000E-02, 1.50000E-02, 2.00000E-02
488 , 3.00000E-02, 3.45614E-02, 3.45614E-02
489 , 4.00000E-02, 5.00000E-02, 6.00000E-02
490 , 8.00000E-02, 1.00000E-01, 1.50000E-01
491 , 2.00000E-01, 3.00000E-01, 4.00000E-01
492 , 5.00000E-01, 6.00000E-01, 8.00000E-01
493 , 1.00000E+00, 1.25000E+00, 1.50000E+00
494 , 2.00000E+00, 3.00000E+00, 4.00000E+00
495 , 5.00000E+00, 6.00000E+00, 8.00000E+00
496 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
497
498 return Interpolate(energyMeV,en,mu,kN);
499
500}
501
502//_____________________________________________________________________________
503Double_t AliTRDsim::GetMuBu(Double_t energyMeV)
504{
505 //
506 // Returns the photon absorbtion cross section for isobutane
507 //
508
509 const Int_t kN = 36;
510
511 Double_t mu[kN] = { 0.38846E+03, 0.12291E+03, 0.53225E+02
512 , 0.16091E+02, 0.69114E+01, 0.36541E+01
513 , 0.22282E+01, 0.11149E+01, 0.72887E+00
514 , 0.45053E+00, 0.38167E+00, 0.33920E+00
515 , 0.32155E+00, 0.30949E+00, 0.29960E+00
516 , 0.28317E+00, 0.26937E+00, 0.24228E+00
517 , 0.22190E+00, 0.19289E+00, 0.17288E+00
518 , 0.15789E+00, 0.14602E+00, 0.12829E+00
519 , 0.11533E+00, 0.10310E+00, 0.93790E-01
520 , 0.80117E-01, 0.63330E-01, 0.53229E-01
521 , 0.46390E-01, 0.41425E-01, 0.34668E-01
522 , 0.30267E-01, 0.23910E-01, 0.20509E-01 };
523
524 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
525 , 0.30000E-02, 0.40000E-02, 0.50000E-02
526 , 0.60000E-02, 0.80000E-02, 0.10000E-01
527 , 0.15000E-01, 0.20000E-01, 0.30000E-01
528 , 0.40000E-01, 0.50000E-01, 0.60000E-01
529 , 0.80000E-01, 0.10000E+00, 0.15000E+00
530 , 0.20000E+00, 0.30000E+00, 0.40000E+00
531 , 0.50000E+00, 0.60000E+00, 0.80000E+00
532 , 0.10000E+01, 0.12500E+01, 0.15000E+01
533 , 0.20000E+01, 0.30000E+01, 0.40000E+01
534 , 0.50000E+01, 0.60000E+01, 0.80000E+01
535 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
536
537 return Interpolate(energyMeV,en,mu,kN);
538
539}
540
541//_____________________________________________________________________________
542Double_t AliTRDsim::GetMuMy(Double_t energyMeV)
543{
544 //
545 // Returns the photon absorbtion cross section for mylar
546 //
547
548 const Int_t kN = 36;
549
550 Double_t mu[kN] = { 2.911E+03, 9.536E+02, 4.206E+02
551 , 1.288E+02, 5.466E+01, 2.792E+01
552 , 1.608E+01, 6.750E+00, 3.481E+00
553 , 1.132E+00, 5.798E-01, 3.009E-01
554 , 2.304E-01, 2.020E-01, 1.868E-01
555 , 1.695E-01, 1.586E-01, 1.406E-01
556 , 1.282E-01, 1.111E-01, 9.947E-02
557 , 9.079E-02, 8.395E-02, 7.372E-02
558 , 6.628E-02, 5.927E-02, 5.395E-02
559 , 4.630E-02, 3.715E-02, 3.181E-02
560 , 2.829E-02, 2.582E-02, 2.257E-02
561 , 2.057E-02, 1.789E-02, 1.664E-02 };
562
563 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
564 , 3.00000E-03, 4.00000E-03, 5.00000E-03
565 , 6.00000E-03, 8.00000E-03, 1.00000E-02
566 , 1.50000E-02, 2.00000E-02, 3.00000E-02
567 , 4.00000E-02, 5.00000E-02, 6.00000E-02
568 , 8.00000E-02, 1.00000E-01, 1.50000E-01
569 , 2.00000E-01, 3.00000E-01, 4.00000E-01
570 , 5.00000E-01, 6.00000E-01, 8.00000E-01
571 , 1.00000E+00, 1.25000E+00, 1.50000E+00
572 , 2.00000E+00, 3.00000E+00, 4.00000E+00
573 , 5.00000E+00, 6.00000E+00, 8.00000E+00
574 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
575
576 return Interpolate(energyMeV,en,mu,kN);
577
578}
579
580//_____________________________________________________________________________
581Double_t AliTRDsim::GetMuN2(Double_t energyMeV)
582{
583 //
584 // Returns the photon absorbtion cross section for nitrogen
585 //
586
587 const Int_t kN = 36;
588
589 Double_t mu[kN] = { 3.311E+03, 1.083E+03, 4.769E+02
590 , 1.456E+02, 6.166E+01, 3.144E+01
591 , 1.809E+01, 7.562E+00, 3.879E+00
592 , 1.236E+00, 6.178E-01, 3.066E-01
593 , 2.288E-01, 1.980E-01, 1.817E-01
594 , 1.639E-01, 1.529E-01, 1.353E-01
595 , 1.233E-01, 1.068E-01, 9.557E-02
596 , 8.719E-02, 8.063E-02, 7.081E-02
597 , 6.364E-02, 5.693E-02, 5.180E-02
598 , 4.450E-02, 3.579E-02, 3.073E-02
599 , 2.742E-02, 2.511E-02, 2.209E-02
600 , 2.024E-02, 1.782E-02, 1.673E-02 };
601
602 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
603 , 3.00000E-03, 4.00000E-03, 5.00000E-03
604 , 6.00000E-03, 8.00000E-03, 1.00000E-02
605 , 1.50000E-02, 2.00000E-02, 3.00000E-02
606 , 4.00000E-02, 5.00000E-02, 6.00000E-02
607 , 8.00000E-02, 1.00000E-01, 1.50000E-01
608 , 2.00000E-01, 3.00000E-01, 4.00000E-01
609 , 5.00000E-01, 6.00000E-01, 8.00000E-01
610 , 1.00000E+00, 1.25000E+00, 1.50000E+00
611 , 2.00000E+00, 3.00000E+00, 4.00000E+00
612 , 5.00000E+00, 6.00000E+00, 8.00000E+00
613 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
614
615 return Interpolate(energyMeV,en,mu,kN);
616
617}
618
619//_____________________________________________________________________________
620Double_t AliTRDsim::GetMuO2(Double_t energyMeV)
621{
622 //
623 // Returns the photon absorbtion cross section for oxygen
624 //
625
626 const Int_t kN = 36;
627
628 Double_t mu[kN] = { 4.590E+03, 1.549E+03, 6.949E+02
629 , 2.171E+02, 9.315E+01, 4.790E+01
630 , 2.770E+01, 1.163E+01, 5.952E+00
631 , 1.836E+00, 8.651E-01, 3.779E-01
632 , 2.585E-01, 2.132E-01, 1.907E-01
633 , 1.678E-01, 1.551E-01, 1.361E-01
634 , 1.237E-01, 1.070E-01, 9.566E-02
635 , 8.729E-02, 8.070E-02, 7.087E-02
636 , 6.372E-02, 5.697E-02, 5.185E-02
637 , 4.459E-02, 3.597E-02, 3.100E-02
638 , 2.777E-02, 2.552E-02, 2.263E-02
639 , 2.089E-02, 1.866E-02, 1.770E-02 };
640
641 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
642 , 3.00000E-03, 4.00000E-03, 5.00000E-03
643 , 6.00000E-03, 8.00000E-03, 1.00000E-02
644 , 1.50000E-02, 2.00000E-02, 3.00000E-02
645 , 4.00000E-02, 5.00000E-02, 6.00000E-02
646 , 8.00000E-02, 1.00000E-01, 1.50000E-01
647 , 2.00000E-01, 3.00000E-01, 4.00000E-01
648 , 5.00000E-01, 6.00000E-01, 8.00000E-01
649 , 1.00000E+00, 1.25000E+00, 1.50000E+00
650 , 2.00000E+00, 3.00000E+00, 4.00000E+00
651 , 5.00000E+00, 6.00000E+00, 8.00000E+00
652 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
653
654 return Interpolate(energyMeV,en,mu,kN);
655
656}
657
658//_____________________________________________________________________________
659Double_t AliTRDsim::GetMuHe(Double_t energyMeV)
660{
661 //
662 // Returns the photon absorbtion cross section for helium
663 //
664
665 const Int_t kN = 36;
666
667 Double_t mu[kN] = { 6.084E+01, 1.676E+01, 6.863E+00
668 , 2.007E+00, 9.329E-01, 5.766E-01
669 , 4.195E-01, 2.933E-01, 2.476E-01
670 , 2.092E-01, 1.960E-01, 1.838E-01
671 , 1.763E-01, 1.703E-01, 1.651E-01
672 , 1.562E-01, 1.486E-01, 1.336E-01
673 , 1.224E-01, 1.064E-01, 9.535E-02
674 , 8.707E-02, 8.054E-02, 7.076E-02
675 , 6.362E-02, 5.688E-02, 5.173E-02
676 , 4.422E-02, 3.503E-02, 2.949E-02
677 , 2.577E-02, 2.307E-02, 1.940E-02
678 , 1.703E-02, 1.363E-02, 1.183E-02 };
679
680 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
681 , 3.00000E-03, 4.00000E-03, 5.00000E-03
682 , 6.00000E-03, 8.00000E-03, 1.00000E-02
683 , 1.50000E-02, 2.00000E-02, 3.00000E-02
684 , 4.00000E-02, 5.00000E-02, 6.00000E-02
685 , 8.00000E-02, 1.00000E-01, 1.50000E-01
686 , 2.00000E-01, 3.00000E-01, 4.00000E-01
687 , 5.00000E-01, 6.00000E-01, 8.00000E-01
688 , 1.00000E+00, 1.25000E+00, 1.50000E+00
689 , 2.00000E+00, 3.00000E+00, 4.00000E+00
690 , 5.00000E+00, 6.00000E+00, 8.00000E+00
691 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
692
693 return Interpolate(energyMeV,en,mu,kN);
694
695}
696
697//_____________________________________________________________________________
698Double_t AliTRDsim::Interpolate(Double_t energyMeV
699 , Double_t *en, Double_t *mu, Int_t n)
700{
701 //
702 // Interpolates the photon absorbtion cross section
703 // for a given energy <energyMeV>.
704 //
705
706 Double_t de = 0;
707 Int_t index = 0;
708 Int_t istat = Locate(en,n,energyMeV,index,de);
709 if (istat == 0) {
710 return (mu[index] - de * (mu[index] - mu[index+1])
711 / (en[index+1] - en[index] ));
712 }
713 else {
714 return 0.0;
715 }
716
717}
718
719//_____________________________________________________________________________
720Int_t AliTRDsim::Locate(Double_t *xv, Int_t n, Double_t xval
721 , Int_t &kl, Double_t &dx)
722{
723 //
724 // Locates a point (xval) in a 1-dim grid (xv(n))
725 //
726
727 if (xval >= xv[n-1]) return 1;
728 if (xval < xv[0]) return -1;
729
730 Int_t km;
731 Int_t kh = n - 1;
732
733 kl = 0;
734 while (kh - kl > 1) {
735 if (xval < xv[km = (kl+kh)/2]) kh = km;
736 else kl = km;
737 }
738 if (xval < xv[kl] || xval > xv[kl+1] || kl >= n-1) {
739 printf("Locate failed xv[%d] %f xval %f xv[%d] %f!!!\n"
740 ,kl,xv[kl],xval,kl+1,xv[kl+1]);
741 exit(1);
742 }
743
744 dx = xval - xv[kl];
745
746 return 0;
747
748}