Include the bug fixes by Oliver in the TR simulation
[u/mrichter/AliRoot.git] / TRD / AliTRDsim.cxx
CommitLineData
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$Log$
842287f2 18Revision 1.11 2001/11/14 10:50:46 cblume
19Changes in digits IO. Add merging of summable digits
20
abaf1f1d 21Revision 1.10 2001/05/31 16:53:26 alibrary
22Correction to the destructor
23
5567246e 24Revision 1.9 2001/05/21 16:45:47 hristov
25Last minute changes (C.Blume)
26
db30bf0f 27Revision 1.8 2001/01/26 19:56:57 hristov
28Major upgrade of AliRoot code
29
2ab0c725 30Revision 1.7 2000/12/20 13:00:45 cblume
31Modifications for the HP-compiler
32
d1b06c24 33Revision 1.6 2000/12/12 10:20:10 cblume
34Initialize fSepctrum = 0 in ctors
35
fa5e892a 36Revision 1.5 2000/10/15 23:40:01 cblume
37Remove AliTRDconst
38
0e9c2ad5 39Revision 1.4 2000/10/06 16:49:46 cblume
40Made Getters const
41
46d29e70 42Revision 1.3.2.1 2000/09/18 13:45:30 cblume
43New class AliTRDsim that simulates TR photons
44
45Revision 1.2 1999/09/29 09:24:35 fca
46Introduction of the Copyright and cvs Log
47
48*/
49
50///////////////////////////////////////////////////////////////////////////////
51// //
52// TRD simulation - multimodule (regular rad.) //
53// after: M. CASTELLANO et al., COMP. PHYS. COMM. 51 (1988) 431 //
54// + COMP. PHYS. COMM. 61 (1990) 395 //
55// //
56// 17.07.1998 - A.Andronic //
57// 08.12.1998 - simplified version //
58// 11.07.2000 - Adapted code to aliroot environment (C.Blume) //
59// //
60///////////////////////////////////////////////////////////////////////////////
61
62#include <stdlib.h>
63
0e9c2ad5 64#include <TH1.h>
65#include <TRandom.h>
66#include <TMath.h>
67#include <TParticle.h>
46d29e70 68
46d29e70 69#include "AliModule.h"
70
0e9c2ad5 71#include "AliTRDsim.h"
72
46d29e70 73ClassImp(AliTRDsim)
74
75//_____________________________________________________________________________
76AliTRDsim::AliTRDsim():TObject()
77{
78 //
79 // AliTRDsim default constructor
80 //
81
fa5e892a 82 fSpectrum = 0;
d1b06c24 83 fSigma = 0;
fa5e892a 84
46d29e70 85 Init();
86
87}
88
89//_____________________________________________________________________________
90AliTRDsim::AliTRDsim(AliModule *mod, Int_t foil, Int_t gap)
91{
92 //
93 // AliTRDsim constructor. Takes the material properties of the radiator
94 // foils and the gas in the gaps from AliModule <mod>.
95 // The default number of foils is 100 with a thickness of 20 mu. The
96 // thickness of the gaps is 500 mu.
97 //
98
99 Float_t aFoil, zFoil, rhoFoil;
100 Float_t aGap, zGap, rhoGap;
101 Float_t rad, abs;
102 Char_t name[21];
103
fa5e892a 104 fSpectrum = 0;
d1b06c24 105 fSigma = 0;
fa5e892a 106
46d29e70 107 Init();
108
109 mod->AliGetMaterial(foil,name,aFoil,zFoil,rhoFoil,rad,abs);
110 mod->AliGetMaterial(gap ,name,aGap ,zGap ,rhoGap ,rad,abs);
111
112 fFoilDens = rhoFoil;
113 fFoilA = aFoil;
114 fFoilZ = zFoil;
115 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
116
117 fGapDens = rhoGap;
118 fGapA = aGap;
119 fGapZ = zGap;
120 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
121
122}
123
124//_____________________________________________________________________________
125AliTRDsim::AliTRDsim(const AliTRDsim &s)
126{
127 //
128 // AliTRDsim copy constructor
129 //
130
131 ((AliTRDsim &) s).Copy(*this);
132
133}
134
135//_____________________________________________________________________________
136AliTRDsim::~AliTRDsim()
137{
138 //
139 // AliTRDsim destructor
140 //
141
5567246e 142 // if (fSpectrum) delete fSpectrum;
143 if (fSigma) delete [] fSigma;
46d29e70 144
145}
146
147//_____________________________________________________________________________
148AliTRDsim &AliTRDsim::operator=(const AliTRDsim &s)
149{
150 //
151 // Assignment operator
152 //
153
154 if (this != &s) ((AliTRDsim &) s).Copy(*this);
155 return *this;
156
157}
158
159//_____________________________________________________________________________
160void AliTRDsim::Copy(TObject &s)
161{
162 //
163 // Copy function
164 //
165
166 ((AliTRDsim &) s).fNFoils = fNFoils;
167 ((AliTRDsim &) s).fFoilThick = fFoilThick;
168 ((AliTRDsim &) s).fFoilDens = fFoilDens;
169 ((AliTRDsim &) s).fFoilOmega = fFoilOmega;
170 ((AliTRDsim &) s).fFoilZ = fFoilZ;
171 ((AliTRDsim &) s).fFoilA = fFoilA;
172 ((AliTRDsim &) s).fGapThick = fGapThick;
173 ((AliTRDsim &) s).fGapDens = fGapDens;
174 ((AliTRDsim &) s).fGapOmega = fGapOmega;
175 ((AliTRDsim &) s).fGapZ = fGapZ;
176 ((AliTRDsim &) s).fGapA = fGapA;
177 ((AliTRDsim &) s).fTemp = fTemp;
178 ((AliTRDsim &) s).fSpNBins = fSpNBins;
179 ((AliTRDsim &) s).fSpRange = fSpRange;
180 ((AliTRDsim &) s).fSpBinWidth = fSpBinWidth;
181 ((AliTRDsim &) s).fSpLower = fSpLower;
182 ((AliTRDsim &) s).fSpUpper = fSpUpper;
183
5567246e 184 if (((AliTRDsim &) s).fSigma) delete [] ((AliTRDsim &) s).fSigma;
46d29e70 185 ((AliTRDsim &) s).fSigma = new Double_t[fSpNBins];
186 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
187 ((AliTRDsim &) s).fSigma[iBin] = fSigma[iBin];
188 }
189
190 fSpectrum->Copy(*((AliTRDsim &) s).fSpectrum);
191
192}
193
194//_____________________________________________________________________________
195void AliTRDsim::Init()
196{
197 //
198 // Initialization
db30bf0f 199 // The default radiator are 100 prolypropilene foils of 13 mu thickness
200 // with gaps of 60 mu filled with CO2.
46d29e70 201 //
202
203 fNFoils = 100;
204
db30bf0f 205 fFoilThick = 0.0013;
46d29e70 206 fFoilDens = 0.92;
207 fFoilZ = 5.28571;
208 fFoilA = 10.4286;
209 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
210
db30bf0f 211 fGapThick = 0.0060;
46d29e70 212 fGapDens = 0.001977;
213 fGapZ = 7.45455;
214 fGapA = 14.9091;
215 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
216
217 fTemp = 293.16;
218
219 fSpNBins = 200;
220 fSpRange = 100;
221 fSpBinWidth = fSpRange / fSpNBins;
222 fSpLower = 1.0 - 0.5 * fSpBinWidth;
223 fSpUpper = fSpLower + fSpRange;
224
225 if (fSpectrum) delete fSpectrum;
226 fSpectrum = new TH1D("TRspectrum","TR spectrum",fSpNBins,fSpLower,fSpUpper);
abaf1f1d 227 fSpectrum->SetDirectory(0);
46d29e70 228
229 // Set the sigma values
230 SetSigma();
231
232}
233
234//_____________________________________________________________________________
235Int_t AliTRDsim::CreatePhotons(Int_t pdg, Float_t p
236 , Int_t &nPhoton, Float_t *ePhoton)
237{
238 //
239 // Create TRD photons for a charged particle of type <pdg> with the total
240 // momentum <p>.
241 // Number of produced TR photons: <nPhoton>
242 // Energies of the produced TR photons: <ePhoton>
243 //
244
245 // PDG codes
246 const Int_t kPdgEle = 11;
247 const Int_t kPdgMuon = 13;
248 const Int_t kPdgPion = 211;
249 const Int_t kPdgKaon = 321;
250
251 Float_t mass = 0;
252 switch (TMath::Abs(pdg)) {
253 case kPdgEle:
254 mass = 5.11e-4;
255 break;
256 case kPdgMuon:
257 mass = 0.10566;
258 break;
259 case kPdgPion:
260 mass = 0.13957;
261 break;
262 case kPdgKaon:
263 mass = 0.4937;
264 break;
265 default:
266 return 0;
267 break;
268 };
269
270 // Calculate gamma
271 Double_t gamma = TMath::Sqrt(p*p + mass*mass) / mass;
272
273 // Calculate the TR photons
274 return TrPhotons(gamma, nPhoton, ePhoton);
275
276}
277
278//_____________________________________________________________________________
279Int_t AliTRDsim::TrPhotons(Double_t gamma, Int_t &nPhoton, Float_t *ePhoton)
280{
281 //
282 // Produces TR photons.
283 //
284
285 const Double_t kAlpha = 0.0072973;
286 const Int_t kSumMax = 10;
287
288 Double_t kappa = fGapThick / fFoilThick;
289
290 fSpectrum->Reset();
291
292 // The TR spectrum
293 Double_t stemp = 0;
294 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
295
296 // keV -> eV
297 Double_t energyeV = (fSpBinWidth * iBin + 1.0) * 1e3;
298
299 Double_t csFoil = fFoilOmega / energyeV;
300 Double_t csGap = fGapOmega / energyeV;
301
302 Double_t rho1 = energyeV * fFoilThick * 1e4 * 2.5
303 * (1.0 / (gamma*gamma) + csFoil*csFoil);
304 Double_t rho2 = energyeV * fFoilThick * 1e4 * 2.5
305 * (1.0 / (gamma*gamma) + csGap *csGap);
306
307 // Calculate the sum
308 Double_t sum = 0;
309 for (Int_t iSum = 0; iSum < kSumMax; iSum++) {
310 Double_t tetan = (TMath::Pi() * 2.0 * (iSum+1) - (rho1 + kappa * rho2))
311 / (kappa + 1.0);
312 if (tetan < 0.0) tetan = 0.0;
313 Double_t aux = 1.0 / (rho1 + tetan) - 1.0 / (rho2 + tetan);
314 sum += tetan * (aux*aux) * (1.0 - TMath::Cos(rho1 + tetan));
315 }
316
317 // Absorbtion
318 Double_t conv = 1.0 - TMath::Exp(-fNFoils * fSigma[iBin]);
319
320 // eV -> keV
321 Float_t energykeV = energyeV * 0.001;
322
323 // dN / domega
324 Double_t wn = kAlpha * 4.0 / (fSigma[iBin] * (kappa + 1.0))
325 * conv * sum / energykeV;
326 fSpectrum->SetBinContent(iBin,wn);
327
328 stemp += wn;
329
330 }
331
332 // <nTR> (binsize corr.)
333 Float_t ntr = stemp * fSpBinWidth;
334 // Number of TR photons from Poisson distribution with mean <ntr>
335 nPhoton = gRandom->Poisson(ntr);
336 // Energy of the TR photons
337 for (Int_t iPhoton = 0; iPhoton < nPhoton; iPhoton++) {
338 ePhoton[iPhoton] = fSpectrum->GetRandom();
339 }
340
341 return 1;
342
343}
344
345//_____________________________________________________________________________
346void AliTRDsim::SetSigma()
347{
348 //
349 // Sets the absorbtion crosssection for the energies of the TR spectrum
350 //
351
5567246e 352 if (fSigma) delete [] fSigma;
46d29e70 353 fSigma = new Double_t[fSpNBins];
354 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
355 Double_t energykeV = iBin * fSpBinWidth + 1.0;
356 fSigma[iBin] = Sigma(energykeV);
357 //printf("SetSigma(): iBin = %d fSigma %g\n",iBin,fSigma[iBin]);
358 }
359
360}
361
362//_____________________________________________________________________________
363Double_t AliTRDsim::Sigma(Double_t energykeV)
364{
365 //
366 // Calculates the absorbtion crosssection for a one-foil-one-gap-radiator
367 //
368
46d29e70 369 // keV -> MeV
370 Double_t energyMeV = energykeV * 0.001;
371 if (energyMeV >= 0.001) {
842287f2 372 return(GetMuPo(energyMeV) * fFoilDens * fFoilThick +
373 GetMuAi(energyMeV) * fGapDens * fGapThick * GetTemp());
46d29e70 374 }
375 else {
376 return 1e6;
377 }
378
379}
380
381//_____________________________________________________________________________
382Double_t AliTRDsim::GetMuPo(Double_t energyMeV)
383{
384 //
385 // Returns the photon absorbtion cross section for polypropylene
386 //
387
388 const Int_t kN = 36;
389
390 Double_t mu[kN] = { 1.894E+03, 5.999E+02, 2.593E+02
391 , 7.743E+01, 3.242E+01, 1.643E+01
392 , 9.432E+00, 3.975E+00, 2.088E+00
393 , 7.452E-01, 4.315E-01, 2.706E-01
394 , 2.275E-01, 2.084E-01, 1.970E-01
395 , 1.823E-01, 1.719E-01, 1.534E-01
396 , 1.402E-01, 1.217E-01, 1.089E-01
397 , 9.947E-02, 9.198E-02, 8.078E-02
398 , 7.262E-02, 6.495E-02, 5.910E-02
399 , 5.064E-02, 4.045E-02, 3.444E-02
400 , 3.045E-02, 2.760E-02, 2.383E-02
401 , 2.145E-02, 1.819E-02, 1.658E-02 };
402
403 Double_t en[kN] = { 1.000E-03, 1.500E-03, 2.000E-03
404 , 3.000E-03, 4.000E-03, 5.000E-03
405 , 6.000E-03, 8.000E-03, 1.000E-02
406 , 1.500E-02, 2.000E-02, 3.000E-02
407 , 4.000E-02, 5.000E-02, 6.000E-02
408 , 8.000E-02, 1.000E-01, 1.500E-01
409 , 2.000E-01, 3.000E-01, 4.000E-01
410 , 5.000E-01, 6.000E-01, 8.000E-01
411 , 1.000E+00, 1.250E+00, 1.500E+00
412 , 2.000E+00, 3.000E+00, 4.000E+00
413 , 5.000E+00, 6.000E+00, 8.000E+00
414 , 1.000E+01, 1.500E+01, 2.000E+01 };
415
416 return Interpolate(energyMeV,en,mu,kN);
417
418}
419
420//_____________________________________________________________________________
421Double_t AliTRDsim::GetMuCO(Double_t energyMeV)
422{
423 //
424 // Returns the photon absorbtion cross section for CO2
425 //
426
427 const Int_t kN = 36;
428
429 Double_t mu[kN] = { 0.39383E+04, 0.13166E+04, 0.58750E+03
430 , 0.18240E+03, 0.77996E+02, 0.40024E+02
431 , 0.23116E+02, 0.96997E+01, 0.49726E+01
432 , 0.15543E+01, 0.74915E+00, 0.34442E+00
433 , 0.24440E+00, 0.20589E+00, 0.18632E+00
434 , 0.16578E+00, 0.15394E+00, 0.13558E+00
435 , 0.12336E+00, 0.10678E+00, 0.95510E-01
436 , 0.87165E-01, 0.80587E-01, 0.70769E-01
437 , 0.63626E-01, 0.56894E-01, 0.51782E-01
438 , 0.44499E-01, 0.35839E-01, 0.30825E-01
439 , 0.27555E-01, 0.25269E-01, 0.22311E-01
440 , 0.20516E-01, 0.18184E-01, 0.17152E-01 };
441
442 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
443 , 0.30000E-02, 0.40000E-02, 0.50000E-02
444 , 0.60000E-02, 0.80000E-02, 0.10000E-01
445 , 0.15000E-01, 0.20000E-01, 0.30000E-01
446 , 0.40000E-01, 0.50000E-01, 0.60000E-01
447 , 0.80000E-01, 0.10000E+00, 0.15000E+00
448 , 0.20000E+00, 0.30000E+00, 0.40000E+00
449 , 0.50000E+00, 0.60000E+00, 0.80000E+00
450 , 0.10000E+01, 0.12500E+01, 0.15000E+01
451 , 0.20000E+01, 0.30000E+01, 0.40000E+01
452 , 0.50000E+01, 0.60000E+01, 0.80000E+01
453 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
454
455 return Interpolate(energyMeV,en,mu,kN);
456
457}
458
459//_____________________________________________________________________________
460Double_t AliTRDsim::GetMuXe(Double_t energyMeV)
461{
462 //
463 // Returns the photon absorbtion cross section for xenon
464 //
465
466 const Int_t kN = 48;
467
468 Double_t mu[kN] = { 9.413E+03, 8.151E+03, 7.035E+03
469 , 7.338E+03, 4.085E+03, 2.088E+03
470 , 7.780E+02, 3.787E+02, 2.408E+02
471 , 6.941E+02, 6.392E+02, 6.044E+02
472 , 8.181E+02, 7.579E+02, 6.991E+02
473 , 8.064E+02, 6.376E+02, 3.032E+02
474 , 1.690E+02, 5.743E+01, 2.652E+01
475 , 8.930E+00, 6.129E+00, 3.316E+01
476 , 2.270E+01, 1.272E+01, 7.825E+00
477 , 3.633E+00, 2.011E+00, 7.202E-01
478 , 3.760E-01, 1.797E-01, 1.223E-01
479 , 9.699E-02, 8.281E-02, 6.696E-02
480 , 5.785E-02, 5.054E-02, 4.594E-02
481 , 4.078E-02, 3.681E-02, 3.577E-02
482 , 3.583E-02, 3.634E-02, 3.797E-02
483 , 3.987E-02, 4.445E-02, 4.815E-02 };
484
485 Double_t en[kN] = { 1.00000E-03, 1.07191E-03, 1.14900E-03
486 , 1.14900E-03, 1.50000E-03, 2.00000E-03
487 , 3.00000E-03, 4.00000E-03, 4.78220E-03
488 , 4.78220E-03, 5.00000E-03, 5.10370E-03
489 , 5.10370E-03, 5.27536E-03, 5.45280E-03
490 , 5.45280E-03, 6.00000E-03, 8.00000E-03
491 , 1.00000E-02, 1.50000E-02, 2.00000E-02
492 , 3.00000E-02, 3.45614E-02, 3.45614E-02
493 , 4.00000E-02, 5.00000E-02, 6.00000E-02
494 , 8.00000E-02, 1.00000E-01, 1.50000E-01
495 , 2.00000E-01, 3.00000E-01, 4.00000E-01
496 , 5.00000E-01, 6.00000E-01, 8.00000E-01
497 , 1.00000E+00, 1.25000E+00, 1.50000E+00
498 , 2.00000E+00, 3.00000E+00, 4.00000E+00
499 , 5.00000E+00, 6.00000E+00, 8.00000E+00
500 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
501
502 return Interpolate(energyMeV,en,mu,kN);
503
504}
505
506//_____________________________________________________________________________
507Double_t AliTRDsim::GetMuBu(Double_t energyMeV)
508{
509 //
510 // Returns the photon absorbtion cross section for isobutane
511 //
512
513 const Int_t kN = 36;
514
515 Double_t mu[kN] = { 0.38846E+03, 0.12291E+03, 0.53225E+02
516 , 0.16091E+02, 0.69114E+01, 0.36541E+01
517 , 0.22282E+01, 0.11149E+01, 0.72887E+00
518 , 0.45053E+00, 0.38167E+00, 0.33920E+00
519 , 0.32155E+00, 0.30949E+00, 0.29960E+00
520 , 0.28317E+00, 0.26937E+00, 0.24228E+00
521 , 0.22190E+00, 0.19289E+00, 0.17288E+00
522 , 0.15789E+00, 0.14602E+00, 0.12829E+00
523 , 0.11533E+00, 0.10310E+00, 0.93790E-01
524 , 0.80117E-01, 0.63330E-01, 0.53229E-01
525 , 0.46390E-01, 0.41425E-01, 0.34668E-01
526 , 0.30267E-01, 0.23910E-01, 0.20509E-01 };
527
528 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
529 , 0.30000E-02, 0.40000E-02, 0.50000E-02
530 , 0.60000E-02, 0.80000E-02, 0.10000E-01
531 , 0.15000E-01, 0.20000E-01, 0.30000E-01
532 , 0.40000E-01, 0.50000E-01, 0.60000E-01
533 , 0.80000E-01, 0.10000E+00, 0.15000E+00
534 , 0.20000E+00, 0.30000E+00, 0.40000E+00
535 , 0.50000E+00, 0.60000E+00, 0.80000E+00
536 , 0.10000E+01, 0.12500E+01, 0.15000E+01
537 , 0.20000E+01, 0.30000E+01, 0.40000E+01
538 , 0.50000E+01, 0.60000E+01, 0.80000E+01
539 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
540
541 return Interpolate(energyMeV,en,mu,kN);
542
543}
544
545//_____________________________________________________________________________
546Double_t AliTRDsim::GetMuMy(Double_t energyMeV)
547{
548 //
549 // Returns the photon absorbtion cross section for mylar
550 //
551
552 const Int_t kN = 36;
553
554 Double_t mu[kN] = { 2.911E+03, 9.536E+02, 4.206E+02
555 , 1.288E+02, 5.466E+01, 2.792E+01
556 , 1.608E+01, 6.750E+00, 3.481E+00
557 , 1.132E+00, 5.798E-01, 3.009E-01
558 , 2.304E-01, 2.020E-01, 1.868E-01
559 , 1.695E-01, 1.586E-01, 1.406E-01
560 , 1.282E-01, 1.111E-01, 9.947E-02
561 , 9.079E-02, 8.395E-02, 7.372E-02
562 , 6.628E-02, 5.927E-02, 5.395E-02
563 , 4.630E-02, 3.715E-02, 3.181E-02
564 , 2.829E-02, 2.582E-02, 2.257E-02
565 , 2.057E-02, 1.789E-02, 1.664E-02 };
566
567 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
568 , 3.00000E-03, 4.00000E-03, 5.00000E-03
569 , 6.00000E-03, 8.00000E-03, 1.00000E-02
570 , 1.50000E-02, 2.00000E-02, 3.00000E-02
571 , 4.00000E-02, 5.00000E-02, 6.00000E-02
572 , 8.00000E-02, 1.00000E-01, 1.50000E-01
573 , 2.00000E-01, 3.00000E-01, 4.00000E-01
574 , 5.00000E-01, 6.00000E-01, 8.00000E-01
575 , 1.00000E+00, 1.25000E+00, 1.50000E+00
576 , 2.00000E+00, 3.00000E+00, 4.00000E+00
577 , 5.00000E+00, 6.00000E+00, 8.00000E+00
578 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
579
580 return Interpolate(energyMeV,en,mu,kN);
581
582}
583
584//_____________________________________________________________________________
585Double_t AliTRDsim::GetMuN2(Double_t energyMeV)
586{
587 //
588 // Returns the photon absorbtion cross section for nitrogen
589 //
590
591 const Int_t kN = 36;
592
593 Double_t mu[kN] = { 3.311E+03, 1.083E+03, 4.769E+02
594 , 1.456E+02, 6.166E+01, 3.144E+01
595 , 1.809E+01, 7.562E+00, 3.879E+00
596 , 1.236E+00, 6.178E-01, 3.066E-01
597 , 2.288E-01, 1.980E-01, 1.817E-01
598 , 1.639E-01, 1.529E-01, 1.353E-01
599 , 1.233E-01, 1.068E-01, 9.557E-02
600 , 8.719E-02, 8.063E-02, 7.081E-02
601 , 6.364E-02, 5.693E-02, 5.180E-02
602 , 4.450E-02, 3.579E-02, 3.073E-02
603 , 2.742E-02, 2.511E-02, 2.209E-02
604 , 2.024E-02, 1.782E-02, 1.673E-02 };
605
606 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
607 , 3.00000E-03, 4.00000E-03, 5.00000E-03
608 , 6.00000E-03, 8.00000E-03, 1.00000E-02
609 , 1.50000E-02, 2.00000E-02, 3.00000E-02
610 , 4.00000E-02, 5.00000E-02, 6.00000E-02
611 , 8.00000E-02, 1.00000E-01, 1.50000E-01
612 , 2.00000E-01, 3.00000E-01, 4.00000E-01
613 , 5.00000E-01, 6.00000E-01, 8.00000E-01
614 , 1.00000E+00, 1.25000E+00, 1.50000E+00
615 , 2.00000E+00, 3.00000E+00, 4.00000E+00
616 , 5.00000E+00, 6.00000E+00, 8.00000E+00
617 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
618
619 return Interpolate(energyMeV,en,mu,kN);
620
621}
622
623//_____________________________________________________________________________
624Double_t AliTRDsim::GetMuO2(Double_t energyMeV)
625{
626 //
627 // Returns the photon absorbtion cross section for oxygen
628 //
629
630 const Int_t kN = 36;
631
632 Double_t mu[kN] = { 4.590E+03, 1.549E+03, 6.949E+02
633 , 2.171E+02, 9.315E+01, 4.790E+01
634 , 2.770E+01, 1.163E+01, 5.952E+00
635 , 1.836E+00, 8.651E-01, 3.779E-01
636 , 2.585E-01, 2.132E-01, 1.907E-01
637 , 1.678E-01, 1.551E-01, 1.361E-01
638 , 1.237E-01, 1.070E-01, 9.566E-02
639 , 8.729E-02, 8.070E-02, 7.087E-02
640 , 6.372E-02, 5.697E-02, 5.185E-02
641 , 4.459E-02, 3.597E-02, 3.100E-02
642 , 2.777E-02, 2.552E-02, 2.263E-02
643 , 2.089E-02, 1.866E-02, 1.770E-02 };
644
645 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
646 , 3.00000E-03, 4.00000E-03, 5.00000E-03
647 , 6.00000E-03, 8.00000E-03, 1.00000E-02
648 , 1.50000E-02, 2.00000E-02, 3.00000E-02
649 , 4.00000E-02, 5.00000E-02, 6.00000E-02
650 , 8.00000E-02, 1.00000E-01, 1.50000E-01
651 , 2.00000E-01, 3.00000E-01, 4.00000E-01
652 , 5.00000E-01, 6.00000E-01, 8.00000E-01
653 , 1.00000E+00, 1.25000E+00, 1.50000E+00
654 , 2.00000E+00, 3.00000E+00, 4.00000E+00
655 , 5.00000E+00, 6.00000E+00, 8.00000E+00
656 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
657
658 return Interpolate(energyMeV,en,mu,kN);
659
660}
661
662//_____________________________________________________________________________
663Double_t AliTRDsim::GetMuHe(Double_t energyMeV)
664{
665 //
666 // Returns the photon absorbtion cross section for helium
667 //
668
669 const Int_t kN = 36;
670
671 Double_t mu[kN] = { 6.084E+01, 1.676E+01, 6.863E+00
672 , 2.007E+00, 9.329E-01, 5.766E-01
673 , 4.195E-01, 2.933E-01, 2.476E-01
674 , 2.092E-01, 1.960E-01, 1.838E-01
675 , 1.763E-01, 1.703E-01, 1.651E-01
676 , 1.562E-01, 1.486E-01, 1.336E-01
677 , 1.224E-01, 1.064E-01, 9.535E-02
678 , 8.707E-02, 8.054E-02, 7.076E-02
679 , 6.362E-02, 5.688E-02, 5.173E-02
680 , 4.422E-02, 3.503E-02, 2.949E-02
681 , 2.577E-02, 2.307E-02, 1.940E-02
682 , 1.703E-02, 1.363E-02, 1.183E-02 };
683
684 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
685 , 3.00000E-03, 4.00000E-03, 5.00000E-03
686 , 6.00000E-03, 8.00000E-03, 1.00000E-02
687 , 1.50000E-02, 2.00000E-02, 3.00000E-02
688 , 4.00000E-02, 5.00000E-02, 6.00000E-02
689 , 8.00000E-02, 1.00000E-01, 1.50000E-01
690 , 2.00000E-01, 3.00000E-01, 4.00000E-01
691 , 5.00000E-01, 6.00000E-01, 8.00000E-01
692 , 1.00000E+00, 1.25000E+00, 1.50000E+00
693 , 2.00000E+00, 3.00000E+00, 4.00000E+00
694 , 5.00000E+00, 6.00000E+00, 8.00000E+00
695 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
696
697 return Interpolate(energyMeV,en,mu,kN);
698
699}
700
842287f2 701//_____________________________________________________________________________
702Double_t AliTRDsim::GetMuAi(Double_t energyMeV)
703{
704 //
705 // Returns the photon absorbtion cross section for air
706 // Implemented by Oliver Busch
707 //
708
709 const Int_t kN = 38;
710
711 Double_t mu[kN] = { 0.35854E+04, 0.11841E+04, 0.52458E+03,
712 0.16143E+03, 0.14250E+03, 0.15722E+03,
713 0.77538E+02, 0.40099E+02, 0.23313E+02,
714 0.98816E+01, 0.51000E+01, 0.16079E+01,
715 0.77536E+00, 0.35282E+00, 0.24790E+00,
716 0.20750E+00, 0.18703E+00, 0.16589E+00,
717 0.15375E+00, 0.13530E+00, 0.12311E+00,
718 0.10654E+00, 0.95297E-01, 0.86939E-01,
719 0.80390E-01, 0.70596E-01, 0.63452E-01,
720 0.56754E-01, 0.51644E-01, 0.44382E-01,
721 0.35733E-01, 0.30721E-01, 0.27450E-01,
722 0.25171E-01, 0.22205E-01, 0.20399E-01,
723 0.18053E-01, 0.18057E-01 };
724
725
726
727 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02,
728 0.30000E-02, 0.32029E-02, 0.32029E-02,
729 0.40000E-02, 0.50000E-02, 0.60000E-02,
730 0.80000E-02, 0.10000E-01, 0.15000E-01,
731 0.20000E-01, 0.30000E-01, 0.40000E-01,
732 0.50000E-01, 0.60000E-01, 0.80000E-01,
733 0.10000E+00, 0.15000E+00, 0.20000E+00,
734 0.30000E+00, 0.40000E+00, 0.50000E+00,
735 0.60000E+00, 0.80000E+00, 0.10000E+01,
736 0.12500E+01, 0.15000E+01, 0.20000E+01,
737 0.30000E+01, 0.40000E+01, 0.50000E+01,
738 0.60000E+01, 0.80000E+01, 0.10000E+02,
739 0.15000E+02, 0.20000E+02 };
740
741 return Interpolate(energyMeV,en,mu,kN);
742
743}
744
46d29e70 745//_____________________________________________________________________________
746Double_t AliTRDsim::Interpolate(Double_t energyMeV
747 , Double_t *en, Double_t *mu, Int_t n)
748{
749 //
750 // Interpolates the photon absorbtion cross section
751 // for a given energy <energyMeV>.
752 //
753
754 Double_t de = 0;
755 Int_t index = 0;
756 Int_t istat = Locate(en,n,energyMeV,index,de);
757 if (istat == 0) {
758 return (mu[index] - de * (mu[index] - mu[index+1])
759 / (en[index+1] - en[index] ));
760 }
761 else {
762 return 0.0;
763 }
764
765}
766
767//_____________________________________________________________________________
768Int_t AliTRDsim::Locate(Double_t *xv, Int_t n, Double_t xval
769 , Int_t &kl, Double_t &dx)
770{
771 //
772 // Locates a point (xval) in a 1-dim grid (xv(n))
773 //
774
775 if (xval >= xv[n-1]) return 1;
776 if (xval < xv[0]) return -1;
777
778 Int_t km;
779 Int_t kh = n - 1;
780
781 kl = 0;
782 while (kh - kl > 1) {
783 if (xval < xv[km = (kl+kh)/2]) kh = km;
784 else kl = km;
785 }
786 if (xval < xv[kl] || xval > xv[kl+1] || kl >= n-1) {
787 printf("Locate failed xv[%d] %f xval %f xv[%d] %f!!!\n"
788 ,kl,xv[kl],xval,kl+1,xv[kl+1]);
789 exit(1);
790 }
791
792 dx = xval - xv[kl];
793
794 return 0;
795
796}