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 1.3.2.1 2000/09/18 13:45:30 cblume
19 New class AliTRDsim that simulates TR photons
21 Revision 1.2 1999/09/29 09:24:35 fca
22 Introduction of the Copyright and cvs Log
26 ///////////////////////////////////////////////////////////////////////////////
28 // TRD simulation - multimodule (regular rad.) //
29 // after: M. CASTELLANO et al., COMP. PHYS. COMM. 51 (1988) 431 //
30 // + COMP. PHYS. COMM. 61 (1990) 395 //
32 // 17.07.1998 - A.Andronic //
33 // 08.12.1998 - simplified version //
34 // 11.07.2000 - Adapted code to aliroot environment (C.Blume) //
36 ///////////////////////////////////////////////////////////////////////////////
43 #include "TParticle.h"
45 #include "AliTRDsim.h"
46 #include "AliTRDconst.h"
47 #include "AliModule.h"
51 //_____________________________________________________________________________
52 AliTRDsim::AliTRDsim():TObject()
55 // AliTRDsim default constructor
62 //_____________________________________________________________________________
63 AliTRDsim::AliTRDsim(AliModule *mod, Int_t foil, Int_t gap)
66 // AliTRDsim constructor. Takes the material properties of the radiator
67 // foils and the gas in the gaps from AliModule <mod>.
68 // The default number of foils is 100 with a thickness of 20 mu. The
69 // thickness of the gaps is 500 mu.
72 Float_t aFoil, zFoil, rhoFoil;
73 Float_t aGap, zGap, rhoGap;
79 mod->AliGetMaterial(foil,name,aFoil,zFoil,rhoFoil,rad,abs);
80 mod->AliGetMaterial(gap ,name,aGap ,zGap ,rhoGap ,rad,abs);
85 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
90 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
94 //_____________________________________________________________________________
95 AliTRDsim::AliTRDsim(const AliTRDsim &s)
98 // AliTRDsim copy constructor
101 ((AliTRDsim &) s).Copy(*this);
105 //_____________________________________________________________________________
106 AliTRDsim::~AliTRDsim()
109 // AliTRDsim destructor
112 if (fSpectrum) delete fSpectrum;
113 if (fSigma) delete fSigma;
117 //_____________________________________________________________________________
118 AliTRDsim &AliTRDsim::operator=(const AliTRDsim &s)
121 // Assignment operator
124 if (this != &s) ((AliTRDsim &) s).Copy(*this);
129 //_____________________________________________________________________________
130 void AliTRDsim::Copy(TObject &s)
136 ((AliTRDsim &) s).fNFoils = fNFoils;
137 ((AliTRDsim &) s).fFoilThick = fFoilThick;
138 ((AliTRDsim &) s).fFoilDens = fFoilDens;
139 ((AliTRDsim &) s).fFoilOmega = fFoilOmega;
140 ((AliTRDsim &) s).fFoilZ = fFoilZ;
141 ((AliTRDsim &) s).fFoilA = fFoilA;
142 ((AliTRDsim &) s).fGapThick = fGapThick;
143 ((AliTRDsim &) s).fGapDens = fGapDens;
144 ((AliTRDsim &) s).fGapOmega = fGapOmega;
145 ((AliTRDsim &) s).fGapZ = fGapZ;
146 ((AliTRDsim &) s).fGapA = fGapA;
147 ((AliTRDsim &) s).fTemp = fTemp;
148 ((AliTRDsim &) s).fSpNBins = fSpNBins;
149 ((AliTRDsim &) s).fSpRange = fSpRange;
150 ((AliTRDsim &) s).fSpBinWidth = fSpBinWidth;
151 ((AliTRDsim &) s).fSpLower = fSpLower;
152 ((AliTRDsim &) s).fSpUpper = fSpUpper;
154 if (((AliTRDsim &) s).fSigma) delete ((AliTRDsim &) s).fSigma;
155 ((AliTRDsim &) s).fSigma = new Double_t[fSpNBins];
156 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
157 ((AliTRDsim &) s).fSigma[iBin] = fSigma[iBin];
160 fSpectrum->Copy(*((AliTRDsim &) s).fSpectrum);
164 //_____________________________________________________________________________
165 void AliTRDsim::Init()
169 // The default radiator are 100 prolypropilene foils of 20 mu thickness
170 // with gaps of 500 mu filled with CO2.
180 fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA);
186 fGapOmega = Omega(fGapDens ,fGapZ ,fGapA );
192 fSpBinWidth = fSpRange / fSpNBins;
193 fSpLower = 1.0 - 0.5 * fSpBinWidth;
194 fSpUpper = fSpLower + fSpRange;
196 if (fSpectrum) delete fSpectrum;
197 fSpectrum = new TH1D("TRspectrum","TR spectrum",fSpNBins,fSpLower,fSpUpper);
199 // Set the sigma values
204 //_____________________________________________________________________________
205 Int_t AliTRDsim::CreatePhotons(Int_t pdg, Float_t p
206 , Int_t &nPhoton, Float_t *ePhoton)
209 // Create TRD photons for a charged particle of type <pdg> with the total
211 // Number of produced TR photons: <nPhoton>
212 // Energies of the produced TR photons: <ePhoton>
216 const Int_t kPdgEle = 11;
217 const Int_t kPdgMuon = 13;
218 const Int_t kPdgPion = 211;
219 const Int_t kPdgKaon = 321;
222 switch (TMath::Abs(pdg)) {
241 Double_t gamma = TMath::Sqrt(p*p + mass*mass) / mass;
243 // Calculate the TR photons
244 return TrPhotons(gamma, nPhoton, ePhoton);
248 //_____________________________________________________________________________
249 Int_t AliTRDsim::TrPhotons(Double_t gamma, Int_t &nPhoton, Float_t *ePhoton)
252 // Produces TR photons.
255 const Double_t kAlpha = 0.0072973;
256 const Int_t kSumMax = 10;
258 Double_t kappa = fGapThick / fFoilThick;
264 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
267 Double_t energyeV = (fSpBinWidth * iBin + 1.0) * 1e3;
269 Double_t csFoil = fFoilOmega / energyeV;
270 Double_t csGap = fGapOmega / energyeV;
272 Double_t rho1 = energyeV * fFoilThick * 1e4 * 2.5
273 * (1.0 / (gamma*gamma) + csFoil*csFoil);
274 Double_t rho2 = energyeV * fFoilThick * 1e4 * 2.5
275 * (1.0 / (gamma*gamma) + csGap *csGap);
279 for (Int_t iSum = 0; iSum < kSumMax; iSum++) {
280 Double_t tetan = (TMath::Pi() * 2.0 * (iSum+1) - (rho1 + kappa * rho2))
282 if (tetan < 0.0) tetan = 0.0;
283 Double_t aux = 1.0 / (rho1 + tetan) - 1.0 / (rho2 + tetan);
284 sum += tetan * (aux*aux) * (1.0 - TMath::Cos(rho1 + tetan));
288 Double_t conv = 1.0 - TMath::Exp(-fNFoils * fSigma[iBin]);
291 Float_t energykeV = energyeV * 0.001;
294 Double_t wn = kAlpha * 4.0 / (fSigma[iBin] * (kappa + 1.0))
295 * conv * sum / energykeV;
296 fSpectrum->SetBinContent(iBin,wn);
302 // <nTR> (binsize corr.)
303 Float_t ntr = stemp * fSpBinWidth;
304 // Number of TR photons from Poisson distribution with mean <ntr>
305 nPhoton = gRandom->Poisson(ntr);
306 // Energy of the TR photons
307 for (Int_t iPhoton = 0; iPhoton < nPhoton; iPhoton++) {
308 ePhoton[iPhoton] = fSpectrum->GetRandom();
315 //_____________________________________________________________________________
316 void AliTRDsim::SetSigma()
319 // Sets the absorbtion crosssection for the energies of the TR spectrum
322 if (fSigma) delete fSigma;
323 fSigma = new Double_t[fSpNBins];
324 for (Int_t iBin = 0; iBin < fSpNBins; iBin++) {
325 Double_t energykeV = iBin * fSpBinWidth + 1.0;
326 fSigma[iBin] = Sigma(energykeV);
327 //printf("SetSigma(): iBin = %d fSigma %g\n",iBin,fSigma[iBin]);
332 //_____________________________________________________________________________
333 Double_t AliTRDsim::Sigma(Double_t energykeV)
336 // Calculates the absorbtion crosssection for a one-foil-one-gap-radiator
340 const Double_t kTemp0 = 273.16;
343 Double_t energyMeV = energykeV * 0.001;
344 if (energyMeV >= 0.001) {
345 return(GetMuPo(energyMeV) * fFoilDens * fFoilThick +
346 GetMuCO(energyMeV) * fGapDens * fGapThick * fTemp/kTemp0);
354 //_____________________________________________________________________________
355 Double_t AliTRDsim::GetMuPo(Double_t energyMeV)
358 // Returns the photon absorbtion cross section for polypropylene
363 Double_t mu[kN] = { 1.894E+03, 5.999E+02, 2.593E+02
364 , 7.743E+01, 3.242E+01, 1.643E+01
365 , 9.432E+00, 3.975E+00, 2.088E+00
366 , 7.452E-01, 4.315E-01, 2.706E-01
367 , 2.275E-01, 2.084E-01, 1.970E-01
368 , 1.823E-01, 1.719E-01, 1.534E-01
369 , 1.402E-01, 1.217E-01, 1.089E-01
370 , 9.947E-02, 9.198E-02, 8.078E-02
371 , 7.262E-02, 6.495E-02, 5.910E-02
372 , 5.064E-02, 4.045E-02, 3.444E-02
373 , 3.045E-02, 2.760E-02, 2.383E-02
374 , 2.145E-02, 1.819E-02, 1.658E-02 };
376 Double_t en[kN] = { 1.000E-03, 1.500E-03, 2.000E-03
377 , 3.000E-03, 4.000E-03, 5.000E-03
378 , 6.000E-03, 8.000E-03, 1.000E-02
379 , 1.500E-02, 2.000E-02, 3.000E-02
380 , 4.000E-02, 5.000E-02, 6.000E-02
381 , 8.000E-02, 1.000E-01, 1.500E-01
382 , 2.000E-01, 3.000E-01, 4.000E-01
383 , 5.000E-01, 6.000E-01, 8.000E-01
384 , 1.000E+00, 1.250E+00, 1.500E+00
385 , 2.000E+00, 3.000E+00, 4.000E+00
386 , 5.000E+00, 6.000E+00, 8.000E+00
387 , 1.000E+01, 1.500E+01, 2.000E+01 };
389 return Interpolate(energyMeV,en,mu,kN);
393 //_____________________________________________________________________________
394 Double_t AliTRDsim::GetMuCO(Double_t energyMeV)
397 // Returns the photon absorbtion cross section for CO2
402 Double_t mu[kN] = { 0.39383E+04, 0.13166E+04, 0.58750E+03
403 , 0.18240E+03, 0.77996E+02, 0.40024E+02
404 , 0.23116E+02, 0.96997E+01, 0.49726E+01
405 , 0.15543E+01, 0.74915E+00, 0.34442E+00
406 , 0.24440E+00, 0.20589E+00, 0.18632E+00
407 , 0.16578E+00, 0.15394E+00, 0.13558E+00
408 , 0.12336E+00, 0.10678E+00, 0.95510E-01
409 , 0.87165E-01, 0.80587E-01, 0.70769E-01
410 , 0.63626E-01, 0.56894E-01, 0.51782E-01
411 , 0.44499E-01, 0.35839E-01, 0.30825E-01
412 , 0.27555E-01, 0.25269E-01, 0.22311E-01
413 , 0.20516E-01, 0.18184E-01, 0.17152E-01 };
415 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
416 , 0.30000E-02, 0.40000E-02, 0.50000E-02
417 , 0.60000E-02, 0.80000E-02, 0.10000E-01
418 , 0.15000E-01, 0.20000E-01, 0.30000E-01
419 , 0.40000E-01, 0.50000E-01, 0.60000E-01
420 , 0.80000E-01, 0.10000E+00, 0.15000E+00
421 , 0.20000E+00, 0.30000E+00, 0.40000E+00
422 , 0.50000E+00, 0.60000E+00, 0.80000E+00
423 , 0.10000E+01, 0.12500E+01, 0.15000E+01
424 , 0.20000E+01, 0.30000E+01, 0.40000E+01
425 , 0.50000E+01, 0.60000E+01, 0.80000E+01
426 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
428 return Interpolate(energyMeV,en,mu,kN);
432 //_____________________________________________________________________________
433 Double_t AliTRDsim::GetMuXe(Double_t energyMeV)
436 // Returns the photon absorbtion cross section for xenon
441 Double_t mu[kN] = { 9.413E+03, 8.151E+03, 7.035E+03
442 , 7.338E+03, 4.085E+03, 2.088E+03
443 , 7.780E+02, 3.787E+02, 2.408E+02
444 , 6.941E+02, 6.392E+02, 6.044E+02
445 , 8.181E+02, 7.579E+02, 6.991E+02
446 , 8.064E+02, 6.376E+02, 3.032E+02
447 , 1.690E+02, 5.743E+01, 2.652E+01
448 , 8.930E+00, 6.129E+00, 3.316E+01
449 , 2.270E+01, 1.272E+01, 7.825E+00
450 , 3.633E+00, 2.011E+00, 7.202E-01
451 , 3.760E-01, 1.797E-01, 1.223E-01
452 , 9.699E-02, 8.281E-02, 6.696E-02
453 , 5.785E-02, 5.054E-02, 4.594E-02
454 , 4.078E-02, 3.681E-02, 3.577E-02
455 , 3.583E-02, 3.634E-02, 3.797E-02
456 , 3.987E-02, 4.445E-02, 4.815E-02 };
458 Double_t en[kN] = { 1.00000E-03, 1.07191E-03, 1.14900E-03
459 , 1.14900E-03, 1.50000E-03, 2.00000E-03
460 , 3.00000E-03, 4.00000E-03, 4.78220E-03
461 , 4.78220E-03, 5.00000E-03, 5.10370E-03
462 , 5.10370E-03, 5.27536E-03, 5.45280E-03
463 , 5.45280E-03, 6.00000E-03, 8.00000E-03
464 , 1.00000E-02, 1.50000E-02, 2.00000E-02
465 , 3.00000E-02, 3.45614E-02, 3.45614E-02
466 , 4.00000E-02, 5.00000E-02, 6.00000E-02
467 , 8.00000E-02, 1.00000E-01, 1.50000E-01
468 , 2.00000E-01, 3.00000E-01, 4.00000E-01
469 , 5.00000E-01, 6.00000E-01, 8.00000E-01
470 , 1.00000E+00, 1.25000E+00, 1.50000E+00
471 , 2.00000E+00, 3.00000E+00, 4.00000E+00
472 , 5.00000E+00, 6.00000E+00, 8.00000E+00
473 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
475 return Interpolate(energyMeV,en,mu,kN);
479 //_____________________________________________________________________________
480 Double_t AliTRDsim::GetMuBu(Double_t energyMeV)
483 // Returns the photon absorbtion cross section for isobutane
488 Double_t mu[kN] = { 0.38846E+03, 0.12291E+03, 0.53225E+02
489 , 0.16091E+02, 0.69114E+01, 0.36541E+01
490 , 0.22282E+01, 0.11149E+01, 0.72887E+00
491 , 0.45053E+00, 0.38167E+00, 0.33920E+00
492 , 0.32155E+00, 0.30949E+00, 0.29960E+00
493 , 0.28317E+00, 0.26937E+00, 0.24228E+00
494 , 0.22190E+00, 0.19289E+00, 0.17288E+00
495 , 0.15789E+00, 0.14602E+00, 0.12829E+00
496 , 0.11533E+00, 0.10310E+00, 0.93790E-01
497 , 0.80117E-01, 0.63330E-01, 0.53229E-01
498 , 0.46390E-01, 0.41425E-01, 0.34668E-01
499 , 0.30267E-01, 0.23910E-01, 0.20509E-01 };
501 Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02
502 , 0.30000E-02, 0.40000E-02, 0.50000E-02
503 , 0.60000E-02, 0.80000E-02, 0.10000E-01
504 , 0.15000E-01, 0.20000E-01, 0.30000E-01
505 , 0.40000E-01, 0.50000E-01, 0.60000E-01
506 , 0.80000E-01, 0.10000E+00, 0.15000E+00
507 , 0.20000E+00, 0.30000E+00, 0.40000E+00
508 , 0.50000E+00, 0.60000E+00, 0.80000E+00
509 , 0.10000E+01, 0.12500E+01, 0.15000E+01
510 , 0.20000E+01, 0.30000E+01, 0.40000E+01
511 , 0.50000E+01, 0.60000E+01, 0.80000E+01
512 , 0.10000E+02, 0.15000E+02, 0.20000E+02 };
514 return Interpolate(energyMeV,en,mu,kN);
518 //_____________________________________________________________________________
519 Double_t AliTRDsim::GetMuMy(Double_t energyMeV)
522 // Returns the photon absorbtion cross section for mylar
527 Double_t mu[kN] = { 2.911E+03, 9.536E+02, 4.206E+02
528 , 1.288E+02, 5.466E+01, 2.792E+01
529 , 1.608E+01, 6.750E+00, 3.481E+00
530 , 1.132E+00, 5.798E-01, 3.009E-01
531 , 2.304E-01, 2.020E-01, 1.868E-01
532 , 1.695E-01, 1.586E-01, 1.406E-01
533 , 1.282E-01, 1.111E-01, 9.947E-02
534 , 9.079E-02, 8.395E-02, 7.372E-02
535 , 6.628E-02, 5.927E-02, 5.395E-02
536 , 4.630E-02, 3.715E-02, 3.181E-02
537 , 2.829E-02, 2.582E-02, 2.257E-02
538 , 2.057E-02, 1.789E-02, 1.664E-02 };
540 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
541 , 3.00000E-03, 4.00000E-03, 5.00000E-03
542 , 6.00000E-03, 8.00000E-03, 1.00000E-02
543 , 1.50000E-02, 2.00000E-02, 3.00000E-02
544 , 4.00000E-02, 5.00000E-02, 6.00000E-02
545 , 8.00000E-02, 1.00000E-01, 1.50000E-01
546 , 2.00000E-01, 3.00000E-01, 4.00000E-01
547 , 5.00000E-01, 6.00000E-01, 8.00000E-01
548 , 1.00000E+00, 1.25000E+00, 1.50000E+00
549 , 2.00000E+00, 3.00000E+00, 4.00000E+00
550 , 5.00000E+00, 6.00000E+00, 8.00000E+00
551 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
553 return Interpolate(energyMeV,en,mu,kN);
557 //_____________________________________________________________________________
558 Double_t AliTRDsim::GetMuN2(Double_t energyMeV)
561 // Returns the photon absorbtion cross section for nitrogen
566 Double_t mu[kN] = { 3.311E+03, 1.083E+03, 4.769E+02
567 , 1.456E+02, 6.166E+01, 3.144E+01
568 , 1.809E+01, 7.562E+00, 3.879E+00
569 , 1.236E+00, 6.178E-01, 3.066E-01
570 , 2.288E-01, 1.980E-01, 1.817E-01
571 , 1.639E-01, 1.529E-01, 1.353E-01
572 , 1.233E-01, 1.068E-01, 9.557E-02
573 , 8.719E-02, 8.063E-02, 7.081E-02
574 , 6.364E-02, 5.693E-02, 5.180E-02
575 , 4.450E-02, 3.579E-02, 3.073E-02
576 , 2.742E-02, 2.511E-02, 2.209E-02
577 , 2.024E-02, 1.782E-02, 1.673E-02 };
579 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
580 , 3.00000E-03, 4.00000E-03, 5.00000E-03
581 , 6.00000E-03, 8.00000E-03, 1.00000E-02
582 , 1.50000E-02, 2.00000E-02, 3.00000E-02
583 , 4.00000E-02, 5.00000E-02, 6.00000E-02
584 , 8.00000E-02, 1.00000E-01, 1.50000E-01
585 , 2.00000E-01, 3.00000E-01, 4.00000E-01
586 , 5.00000E-01, 6.00000E-01, 8.00000E-01
587 , 1.00000E+00, 1.25000E+00, 1.50000E+00
588 , 2.00000E+00, 3.00000E+00, 4.00000E+00
589 , 5.00000E+00, 6.00000E+00, 8.00000E+00
590 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
592 return Interpolate(energyMeV,en,mu,kN);
596 //_____________________________________________________________________________
597 Double_t AliTRDsim::GetMuO2(Double_t energyMeV)
600 // Returns the photon absorbtion cross section for oxygen
605 Double_t mu[kN] = { 4.590E+03, 1.549E+03, 6.949E+02
606 , 2.171E+02, 9.315E+01, 4.790E+01
607 , 2.770E+01, 1.163E+01, 5.952E+00
608 , 1.836E+00, 8.651E-01, 3.779E-01
609 , 2.585E-01, 2.132E-01, 1.907E-01
610 , 1.678E-01, 1.551E-01, 1.361E-01
611 , 1.237E-01, 1.070E-01, 9.566E-02
612 , 8.729E-02, 8.070E-02, 7.087E-02
613 , 6.372E-02, 5.697E-02, 5.185E-02
614 , 4.459E-02, 3.597E-02, 3.100E-02
615 , 2.777E-02, 2.552E-02, 2.263E-02
616 , 2.089E-02, 1.866E-02, 1.770E-02 };
618 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
619 , 3.00000E-03, 4.00000E-03, 5.00000E-03
620 , 6.00000E-03, 8.00000E-03, 1.00000E-02
621 , 1.50000E-02, 2.00000E-02, 3.00000E-02
622 , 4.00000E-02, 5.00000E-02, 6.00000E-02
623 , 8.00000E-02, 1.00000E-01, 1.50000E-01
624 , 2.00000E-01, 3.00000E-01, 4.00000E-01
625 , 5.00000E-01, 6.00000E-01, 8.00000E-01
626 , 1.00000E+00, 1.25000E+00, 1.50000E+00
627 , 2.00000E+00, 3.00000E+00, 4.00000E+00
628 , 5.00000E+00, 6.00000E+00, 8.00000E+00
629 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
631 return Interpolate(energyMeV,en,mu,kN);
635 //_____________________________________________________________________________
636 Double_t AliTRDsim::GetMuHe(Double_t energyMeV)
639 // Returns the photon absorbtion cross section for helium
644 Double_t mu[kN] = { 6.084E+01, 1.676E+01, 6.863E+00
645 , 2.007E+00, 9.329E-01, 5.766E-01
646 , 4.195E-01, 2.933E-01, 2.476E-01
647 , 2.092E-01, 1.960E-01, 1.838E-01
648 , 1.763E-01, 1.703E-01, 1.651E-01
649 , 1.562E-01, 1.486E-01, 1.336E-01
650 , 1.224E-01, 1.064E-01, 9.535E-02
651 , 8.707E-02, 8.054E-02, 7.076E-02
652 , 6.362E-02, 5.688E-02, 5.173E-02
653 , 4.422E-02, 3.503E-02, 2.949E-02
654 , 2.577E-02, 2.307E-02, 1.940E-02
655 , 1.703E-02, 1.363E-02, 1.183E-02 };
657 Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03
658 , 3.00000E-03, 4.00000E-03, 5.00000E-03
659 , 6.00000E-03, 8.00000E-03, 1.00000E-02
660 , 1.50000E-02, 2.00000E-02, 3.00000E-02
661 , 4.00000E-02, 5.00000E-02, 6.00000E-02
662 , 8.00000E-02, 1.00000E-01, 1.50000E-01
663 , 2.00000E-01, 3.00000E-01, 4.00000E-01
664 , 5.00000E-01, 6.00000E-01, 8.00000E-01
665 , 1.00000E+00, 1.25000E+00, 1.50000E+00
666 , 2.00000E+00, 3.00000E+00, 4.00000E+00
667 , 5.00000E+00, 6.00000E+00, 8.00000E+00
668 , 1.00000E+01, 1.50000E+01, 2.00000E+01 };
670 return Interpolate(energyMeV,en,mu,kN);
674 //_____________________________________________________________________________
675 Double_t AliTRDsim::Interpolate(Double_t energyMeV
676 , Double_t *en, Double_t *mu, Int_t n)
679 // Interpolates the photon absorbtion cross section
680 // for a given energy <energyMeV>.
685 Int_t istat = Locate(en,n,energyMeV,index,de);
687 return (mu[index] - de * (mu[index] - mu[index+1])
688 / (en[index+1] - en[index] ));
696 //_____________________________________________________________________________
697 Int_t AliTRDsim::Locate(Double_t *xv, Int_t n, Double_t xval
698 , Int_t &kl, Double_t &dx)
701 // Locates a point (xval) in a 1-dim grid (xv(n))
704 if (xval >= xv[n-1]) return 1;
705 if (xval < xv[0]) return -1;
711 while (kh - kl > 1) {
712 if (xval < xv[km = (kl+kh)/2]) kh = km;
715 if (xval < xv[kl] || xval > xv[kl+1] || kl >= n-1) {
716 printf("Locate failed xv[%d] %f xval %f xv[%d] %f!!!\n"
717 ,kl,xv[kl],xval,kl+1,xv[kl+1]);
727 //_____________________________________________________________________________
728 void AliTRDsim::Streamer(TBuffer &R__b)
731 // Stream an object of class AliTRDsim.
734 if (R__b.IsReading()) {
735 Version_t R__v = R__b.ReadVersion(); if (R__v) { }
736 TObject::Streamer(R__b);
754 R__b.ReadArray(fSigma);
758 R__b.WriteVersion(AliTRDsim::IsA());
759 TObject::Streamer(R__b);
777 R__b.WriteArray(fSigma, fSpNBins);
778 R__b << (TObject*) fSpectrum;