/************************************************************************** * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. * * * * Author: The ALICE Off-line Project. * * Contributors are mentioned in the code where appropriate. * * * * Permission to use, copy, modify and distribute this software and its * * documentation strictly for non-commercial purposes is hereby granted * * without fee, provided that the above copyright notice appears in all * * copies and that both the copyright notice and this permission notice * * appear in the supporting documentation. The authors make no claims * * about the suitability of this software for any purpose. It is * * provided "as is" without express or implied warranty. * **************************************************************************/ /* $Log$ Revision 1.10 2001/05/31 16:53:26 alibrary Correction to the destructor Revision 1.9 2001/05/21 16:45:47 hristov Last minute changes (C.Blume) Revision 1.8 2001/01/26 19:56:57 hristov Major upgrade of AliRoot code Revision 1.7 2000/12/20 13:00:45 cblume Modifications for the HP-compiler Revision 1.6 2000/12/12 10:20:10 cblume Initialize fSepctrum = 0 in ctors Revision 1.5 2000/10/15 23:40:01 cblume Remove AliTRDconst Revision 1.4 2000/10/06 16:49:46 cblume Made Getters const Revision 1.3.2.1 2000/09/18 13:45:30 cblume New class AliTRDsim that simulates TR photons Revision 1.2 1999/09/29 09:24:35 fca Introduction of the Copyright and cvs Log */ /////////////////////////////////////////////////////////////////////////////// // // // TRD simulation - multimodule (regular rad.) // // after: M. CASTELLANO et al., COMP. PHYS. COMM. 51 (1988) 431 // // + COMP. PHYS. COMM. 61 (1990) 395 // // // // 17.07.1998 - A.Andronic // // 08.12.1998 - simplified version // // 11.07.2000 - Adapted code to aliroot environment (C.Blume) // // // /////////////////////////////////////////////////////////////////////////////// #include #include #include #include #include #include "AliModule.h" #include "AliTRDsim.h" ClassImp(AliTRDsim) //_____________________________________________________________________________ AliTRDsim::AliTRDsim():TObject() { // // AliTRDsim default constructor // fSpectrum = 0; fSigma = 0; Init(); } //_____________________________________________________________________________ AliTRDsim::AliTRDsim(AliModule *mod, Int_t foil, Int_t gap) { // // AliTRDsim constructor. Takes the material properties of the radiator // foils and the gas in the gaps from AliModule . // The default number of foils is 100 with a thickness of 20 mu. The // thickness of the gaps is 500 mu. // Float_t aFoil, zFoil, rhoFoil; Float_t aGap, zGap, rhoGap; Float_t rad, abs; Char_t name[21]; fSpectrum = 0; fSigma = 0; Init(); mod->AliGetMaterial(foil,name,aFoil,zFoil,rhoFoil,rad,abs); mod->AliGetMaterial(gap ,name,aGap ,zGap ,rhoGap ,rad,abs); fFoilDens = rhoFoil; fFoilA = aFoil; fFoilZ = zFoil; fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA); fGapDens = rhoGap; fGapA = aGap; fGapZ = zGap; fGapOmega = Omega(fGapDens ,fGapZ ,fGapA ); } //_____________________________________________________________________________ AliTRDsim::AliTRDsim(const AliTRDsim &s) { // // AliTRDsim copy constructor // ((AliTRDsim &) s).Copy(*this); } //_____________________________________________________________________________ AliTRDsim::~AliTRDsim() { // // AliTRDsim destructor // // if (fSpectrum) delete fSpectrum; if (fSigma) delete [] fSigma; } //_____________________________________________________________________________ AliTRDsim &AliTRDsim::operator=(const AliTRDsim &s) { // // Assignment operator // if (this != &s) ((AliTRDsim &) s).Copy(*this); return *this; } //_____________________________________________________________________________ void AliTRDsim::Copy(TObject &s) { // // Copy function // ((AliTRDsim &) s).fNFoils = fNFoils; ((AliTRDsim &) s).fFoilThick = fFoilThick; ((AliTRDsim &) s).fFoilDens = fFoilDens; ((AliTRDsim &) s).fFoilOmega = fFoilOmega; ((AliTRDsim &) s).fFoilZ = fFoilZ; ((AliTRDsim &) s).fFoilA = fFoilA; ((AliTRDsim &) s).fGapThick = fGapThick; ((AliTRDsim &) s).fGapDens = fGapDens; ((AliTRDsim &) s).fGapOmega = fGapOmega; ((AliTRDsim &) s).fGapZ = fGapZ; ((AliTRDsim &) s).fGapA = fGapA; ((AliTRDsim &) s).fTemp = fTemp; ((AliTRDsim &) s).fSpNBins = fSpNBins; ((AliTRDsim &) s).fSpRange = fSpRange; ((AliTRDsim &) s).fSpBinWidth = fSpBinWidth; ((AliTRDsim &) s).fSpLower = fSpLower; ((AliTRDsim &) s).fSpUpper = fSpUpper; if (((AliTRDsim &) s).fSigma) delete [] ((AliTRDsim &) s).fSigma; ((AliTRDsim &) s).fSigma = new Double_t[fSpNBins]; for (Int_t iBin = 0; iBin < fSpNBins; iBin++) { ((AliTRDsim &) s).fSigma[iBin] = fSigma[iBin]; } fSpectrum->Copy(*((AliTRDsim &) s).fSpectrum); } //_____________________________________________________________________________ void AliTRDsim::Init() { // // Initialization // The default radiator are 100 prolypropilene foils of 13 mu thickness // with gaps of 60 mu filled with CO2. // fNFoils = 100; fFoilThick = 0.0013; fFoilDens = 0.92; fFoilZ = 5.28571; fFoilA = 10.4286; fFoilOmega = Omega(fFoilDens,fFoilZ,fFoilA); fGapThick = 0.0060; fGapDens = 0.001977; fGapZ = 7.45455; fGapA = 14.9091; fGapOmega = Omega(fGapDens ,fGapZ ,fGapA ); fTemp = 293.16; fSpNBins = 200; fSpRange = 100; fSpBinWidth = fSpRange / fSpNBins; fSpLower = 1.0 - 0.5 * fSpBinWidth; fSpUpper = fSpLower + fSpRange; if (fSpectrum) delete fSpectrum; fSpectrum = new TH1D("TRspectrum","TR spectrum",fSpNBins,fSpLower,fSpUpper); fSpectrum->SetDirectory(0); // Set the sigma values SetSigma(); } //_____________________________________________________________________________ Int_t AliTRDsim::CreatePhotons(Int_t pdg, Float_t p , Int_t &nPhoton, Float_t *ePhoton) { // // Create TRD photons for a charged particle of type with the total // momentum

. // Number of produced TR photons: // Energies of the produced TR photons: // // PDG codes const Int_t kPdgEle = 11; const Int_t kPdgMuon = 13; const Int_t kPdgPion = 211; const Int_t kPdgKaon = 321; Float_t mass = 0; switch (TMath::Abs(pdg)) { case kPdgEle: mass = 5.11e-4; break; case kPdgMuon: mass = 0.10566; break; case kPdgPion: mass = 0.13957; break; case kPdgKaon: mass = 0.4937; break; default: return 0; break; }; // Calculate gamma Double_t gamma = TMath::Sqrt(p*p + mass*mass) / mass; // Calculate the TR photons return TrPhotons(gamma, nPhoton, ePhoton); } //_____________________________________________________________________________ Int_t AliTRDsim::TrPhotons(Double_t gamma, Int_t &nPhoton, Float_t *ePhoton) { // // Produces TR photons. // const Double_t kAlpha = 0.0072973; const Int_t kSumMax = 10; Double_t kappa = fGapThick / fFoilThick; fSpectrum->Reset(); // The TR spectrum Double_t stemp = 0; for (Int_t iBin = 0; iBin < fSpNBins; iBin++) { // keV -> eV Double_t energyeV = (fSpBinWidth * iBin + 1.0) * 1e3; Double_t csFoil = fFoilOmega / energyeV; Double_t csGap = fGapOmega / energyeV; Double_t rho1 = energyeV * fFoilThick * 1e4 * 2.5 * (1.0 / (gamma*gamma) + csFoil*csFoil); Double_t rho2 = energyeV * fFoilThick * 1e4 * 2.5 * (1.0 / (gamma*gamma) + csGap *csGap); // Calculate the sum Double_t sum = 0; for (Int_t iSum = 0; iSum < kSumMax; iSum++) { Double_t tetan = (TMath::Pi() * 2.0 * (iSum+1) - (rho1 + kappa * rho2)) / (kappa + 1.0); if (tetan < 0.0) tetan = 0.0; Double_t aux = 1.0 / (rho1 + tetan) - 1.0 / (rho2 + tetan); sum += tetan * (aux*aux) * (1.0 - TMath::Cos(rho1 + tetan)); } // Absorbtion Double_t conv = 1.0 - TMath::Exp(-fNFoils * fSigma[iBin]); // eV -> keV Float_t energykeV = energyeV * 0.001; // dN / domega Double_t wn = kAlpha * 4.0 / (fSigma[iBin] * (kappa + 1.0)) * conv * sum / energykeV; fSpectrum->SetBinContent(iBin,wn); stemp += wn; } // (binsize corr.) Float_t ntr = stemp * fSpBinWidth; // Number of TR photons from Poisson distribution with mean nPhoton = gRandom->Poisson(ntr); // Energy of the TR photons for (Int_t iPhoton = 0; iPhoton < nPhoton; iPhoton++) { ePhoton[iPhoton] = fSpectrum->GetRandom(); } return 1; } //_____________________________________________________________________________ void AliTRDsim::SetSigma() { // // Sets the absorbtion crosssection for the energies of the TR spectrum // if (fSigma) delete [] fSigma; fSigma = new Double_t[fSpNBins]; for (Int_t iBin = 0; iBin < fSpNBins; iBin++) { Double_t energykeV = iBin * fSpBinWidth + 1.0; fSigma[iBin] = Sigma(energykeV); //printf("SetSigma(): iBin = %d fSigma %g\n",iBin,fSigma[iBin]); } } //_____________________________________________________________________________ Double_t AliTRDsim::Sigma(Double_t energykeV) { // // Calculates the absorbtion crosssection for a one-foil-one-gap-radiator // // Gas at 0 C const Double_t kTemp0 = 273.16; // keV -> MeV Double_t energyMeV = energykeV * 0.001; if (energyMeV >= 0.001) { return(GetMuPo(energyMeV) * fFoilDens * fFoilThick + GetMuCO(energyMeV) * fGapDens * fGapThick * fTemp/kTemp0); } else { return 1e6; } } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuPo(Double_t energyMeV) { // // Returns the photon absorbtion cross section for polypropylene // const Int_t kN = 36; Double_t mu[kN] = { 1.894E+03, 5.999E+02, 2.593E+02 , 7.743E+01, 3.242E+01, 1.643E+01 , 9.432E+00, 3.975E+00, 2.088E+00 , 7.452E-01, 4.315E-01, 2.706E-01 , 2.275E-01, 2.084E-01, 1.970E-01 , 1.823E-01, 1.719E-01, 1.534E-01 , 1.402E-01, 1.217E-01, 1.089E-01 , 9.947E-02, 9.198E-02, 8.078E-02 , 7.262E-02, 6.495E-02, 5.910E-02 , 5.064E-02, 4.045E-02, 3.444E-02 , 3.045E-02, 2.760E-02, 2.383E-02 , 2.145E-02, 1.819E-02, 1.658E-02 }; Double_t en[kN] = { 1.000E-03, 1.500E-03, 2.000E-03 , 3.000E-03, 4.000E-03, 5.000E-03 , 6.000E-03, 8.000E-03, 1.000E-02 , 1.500E-02, 2.000E-02, 3.000E-02 , 4.000E-02, 5.000E-02, 6.000E-02 , 8.000E-02, 1.000E-01, 1.500E-01 , 2.000E-01, 3.000E-01, 4.000E-01 , 5.000E-01, 6.000E-01, 8.000E-01 , 1.000E+00, 1.250E+00, 1.500E+00 , 2.000E+00, 3.000E+00, 4.000E+00 , 5.000E+00, 6.000E+00, 8.000E+00 , 1.000E+01, 1.500E+01, 2.000E+01 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuCO(Double_t energyMeV) { // // Returns the photon absorbtion cross section for CO2 // const Int_t kN = 36; Double_t mu[kN] = { 0.39383E+04, 0.13166E+04, 0.58750E+03 , 0.18240E+03, 0.77996E+02, 0.40024E+02 , 0.23116E+02, 0.96997E+01, 0.49726E+01 , 0.15543E+01, 0.74915E+00, 0.34442E+00 , 0.24440E+00, 0.20589E+00, 0.18632E+00 , 0.16578E+00, 0.15394E+00, 0.13558E+00 , 0.12336E+00, 0.10678E+00, 0.95510E-01 , 0.87165E-01, 0.80587E-01, 0.70769E-01 , 0.63626E-01, 0.56894E-01, 0.51782E-01 , 0.44499E-01, 0.35839E-01, 0.30825E-01 , 0.27555E-01, 0.25269E-01, 0.22311E-01 , 0.20516E-01, 0.18184E-01, 0.17152E-01 }; Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02 , 0.30000E-02, 0.40000E-02, 0.50000E-02 , 0.60000E-02, 0.80000E-02, 0.10000E-01 , 0.15000E-01, 0.20000E-01, 0.30000E-01 , 0.40000E-01, 0.50000E-01, 0.60000E-01 , 0.80000E-01, 0.10000E+00, 0.15000E+00 , 0.20000E+00, 0.30000E+00, 0.40000E+00 , 0.50000E+00, 0.60000E+00, 0.80000E+00 , 0.10000E+01, 0.12500E+01, 0.15000E+01 , 0.20000E+01, 0.30000E+01, 0.40000E+01 , 0.50000E+01, 0.60000E+01, 0.80000E+01 , 0.10000E+02, 0.15000E+02, 0.20000E+02 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuXe(Double_t energyMeV) { // // Returns the photon absorbtion cross section for xenon // const Int_t kN = 48; Double_t mu[kN] = { 9.413E+03, 8.151E+03, 7.035E+03 , 7.338E+03, 4.085E+03, 2.088E+03 , 7.780E+02, 3.787E+02, 2.408E+02 , 6.941E+02, 6.392E+02, 6.044E+02 , 8.181E+02, 7.579E+02, 6.991E+02 , 8.064E+02, 6.376E+02, 3.032E+02 , 1.690E+02, 5.743E+01, 2.652E+01 , 8.930E+00, 6.129E+00, 3.316E+01 , 2.270E+01, 1.272E+01, 7.825E+00 , 3.633E+00, 2.011E+00, 7.202E-01 , 3.760E-01, 1.797E-01, 1.223E-01 , 9.699E-02, 8.281E-02, 6.696E-02 , 5.785E-02, 5.054E-02, 4.594E-02 , 4.078E-02, 3.681E-02, 3.577E-02 , 3.583E-02, 3.634E-02, 3.797E-02 , 3.987E-02, 4.445E-02, 4.815E-02 }; Double_t en[kN] = { 1.00000E-03, 1.07191E-03, 1.14900E-03 , 1.14900E-03, 1.50000E-03, 2.00000E-03 , 3.00000E-03, 4.00000E-03, 4.78220E-03 , 4.78220E-03, 5.00000E-03, 5.10370E-03 , 5.10370E-03, 5.27536E-03, 5.45280E-03 , 5.45280E-03, 6.00000E-03, 8.00000E-03 , 1.00000E-02, 1.50000E-02, 2.00000E-02 , 3.00000E-02, 3.45614E-02, 3.45614E-02 , 4.00000E-02, 5.00000E-02, 6.00000E-02 , 8.00000E-02, 1.00000E-01, 1.50000E-01 , 2.00000E-01, 3.00000E-01, 4.00000E-01 , 5.00000E-01, 6.00000E-01, 8.00000E-01 , 1.00000E+00, 1.25000E+00, 1.50000E+00 , 2.00000E+00, 3.00000E+00, 4.00000E+00 , 5.00000E+00, 6.00000E+00, 8.00000E+00 , 1.00000E+01, 1.50000E+01, 2.00000E+01 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuBu(Double_t energyMeV) { // // Returns the photon absorbtion cross section for isobutane // const Int_t kN = 36; Double_t mu[kN] = { 0.38846E+03, 0.12291E+03, 0.53225E+02 , 0.16091E+02, 0.69114E+01, 0.36541E+01 , 0.22282E+01, 0.11149E+01, 0.72887E+00 , 0.45053E+00, 0.38167E+00, 0.33920E+00 , 0.32155E+00, 0.30949E+00, 0.29960E+00 , 0.28317E+00, 0.26937E+00, 0.24228E+00 , 0.22190E+00, 0.19289E+00, 0.17288E+00 , 0.15789E+00, 0.14602E+00, 0.12829E+00 , 0.11533E+00, 0.10310E+00, 0.93790E-01 , 0.80117E-01, 0.63330E-01, 0.53229E-01 , 0.46390E-01, 0.41425E-01, 0.34668E-01 , 0.30267E-01, 0.23910E-01, 0.20509E-01 }; Double_t en[kN] = { 0.10000E-02, 0.15000E-02, 0.20000E-02 , 0.30000E-02, 0.40000E-02, 0.50000E-02 , 0.60000E-02, 0.80000E-02, 0.10000E-01 , 0.15000E-01, 0.20000E-01, 0.30000E-01 , 0.40000E-01, 0.50000E-01, 0.60000E-01 , 0.80000E-01, 0.10000E+00, 0.15000E+00 , 0.20000E+00, 0.30000E+00, 0.40000E+00 , 0.50000E+00, 0.60000E+00, 0.80000E+00 , 0.10000E+01, 0.12500E+01, 0.15000E+01 , 0.20000E+01, 0.30000E+01, 0.40000E+01 , 0.50000E+01, 0.60000E+01, 0.80000E+01 , 0.10000E+02, 0.15000E+02, 0.20000E+02 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuMy(Double_t energyMeV) { // // Returns the photon absorbtion cross section for mylar // const Int_t kN = 36; Double_t mu[kN] = { 2.911E+03, 9.536E+02, 4.206E+02 , 1.288E+02, 5.466E+01, 2.792E+01 , 1.608E+01, 6.750E+00, 3.481E+00 , 1.132E+00, 5.798E-01, 3.009E-01 , 2.304E-01, 2.020E-01, 1.868E-01 , 1.695E-01, 1.586E-01, 1.406E-01 , 1.282E-01, 1.111E-01, 9.947E-02 , 9.079E-02, 8.395E-02, 7.372E-02 , 6.628E-02, 5.927E-02, 5.395E-02 , 4.630E-02, 3.715E-02, 3.181E-02 , 2.829E-02, 2.582E-02, 2.257E-02 , 2.057E-02, 1.789E-02, 1.664E-02 }; Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03 , 3.00000E-03, 4.00000E-03, 5.00000E-03 , 6.00000E-03, 8.00000E-03, 1.00000E-02 , 1.50000E-02, 2.00000E-02, 3.00000E-02 , 4.00000E-02, 5.00000E-02, 6.00000E-02 , 8.00000E-02, 1.00000E-01, 1.50000E-01 , 2.00000E-01, 3.00000E-01, 4.00000E-01 , 5.00000E-01, 6.00000E-01, 8.00000E-01 , 1.00000E+00, 1.25000E+00, 1.50000E+00 , 2.00000E+00, 3.00000E+00, 4.00000E+00 , 5.00000E+00, 6.00000E+00, 8.00000E+00 , 1.00000E+01, 1.50000E+01, 2.00000E+01 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuN2(Double_t energyMeV) { // // Returns the photon absorbtion cross section for nitrogen // const Int_t kN = 36; Double_t mu[kN] = { 3.311E+03, 1.083E+03, 4.769E+02 , 1.456E+02, 6.166E+01, 3.144E+01 , 1.809E+01, 7.562E+00, 3.879E+00 , 1.236E+00, 6.178E-01, 3.066E-01 , 2.288E-01, 1.980E-01, 1.817E-01 , 1.639E-01, 1.529E-01, 1.353E-01 , 1.233E-01, 1.068E-01, 9.557E-02 , 8.719E-02, 8.063E-02, 7.081E-02 , 6.364E-02, 5.693E-02, 5.180E-02 , 4.450E-02, 3.579E-02, 3.073E-02 , 2.742E-02, 2.511E-02, 2.209E-02 , 2.024E-02, 1.782E-02, 1.673E-02 }; Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03 , 3.00000E-03, 4.00000E-03, 5.00000E-03 , 6.00000E-03, 8.00000E-03, 1.00000E-02 , 1.50000E-02, 2.00000E-02, 3.00000E-02 , 4.00000E-02, 5.00000E-02, 6.00000E-02 , 8.00000E-02, 1.00000E-01, 1.50000E-01 , 2.00000E-01, 3.00000E-01, 4.00000E-01 , 5.00000E-01, 6.00000E-01, 8.00000E-01 , 1.00000E+00, 1.25000E+00, 1.50000E+00 , 2.00000E+00, 3.00000E+00, 4.00000E+00 , 5.00000E+00, 6.00000E+00, 8.00000E+00 , 1.00000E+01, 1.50000E+01, 2.00000E+01 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuO2(Double_t energyMeV) { // // Returns the photon absorbtion cross section for oxygen // const Int_t kN = 36; Double_t mu[kN] = { 4.590E+03, 1.549E+03, 6.949E+02 , 2.171E+02, 9.315E+01, 4.790E+01 , 2.770E+01, 1.163E+01, 5.952E+00 , 1.836E+00, 8.651E-01, 3.779E-01 , 2.585E-01, 2.132E-01, 1.907E-01 , 1.678E-01, 1.551E-01, 1.361E-01 , 1.237E-01, 1.070E-01, 9.566E-02 , 8.729E-02, 8.070E-02, 7.087E-02 , 6.372E-02, 5.697E-02, 5.185E-02 , 4.459E-02, 3.597E-02, 3.100E-02 , 2.777E-02, 2.552E-02, 2.263E-02 , 2.089E-02, 1.866E-02, 1.770E-02 }; Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03 , 3.00000E-03, 4.00000E-03, 5.00000E-03 , 6.00000E-03, 8.00000E-03, 1.00000E-02 , 1.50000E-02, 2.00000E-02, 3.00000E-02 , 4.00000E-02, 5.00000E-02, 6.00000E-02 , 8.00000E-02, 1.00000E-01, 1.50000E-01 , 2.00000E-01, 3.00000E-01, 4.00000E-01 , 5.00000E-01, 6.00000E-01, 8.00000E-01 , 1.00000E+00, 1.25000E+00, 1.50000E+00 , 2.00000E+00, 3.00000E+00, 4.00000E+00 , 5.00000E+00, 6.00000E+00, 8.00000E+00 , 1.00000E+01, 1.50000E+01, 2.00000E+01 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::GetMuHe(Double_t energyMeV) { // // Returns the photon absorbtion cross section for helium // const Int_t kN = 36; Double_t mu[kN] = { 6.084E+01, 1.676E+01, 6.863E+00 , 2.007E+00, 9.329E-01, 5.766E-01 , 4.195E-01, 2.933E-01, 2.476E-01 , 2.092E-01, 1.960E-01, 1.838E-01 , 1.763E-01, 1.703E-01, 1.651E-01 , 1.562E-01, 1.486E-01, 1.336E-01 , 1.224E-01, 1.064E-01, 9.535E-02 , 8.707E-02, 8.054E-02, 7.076E-02 , 6.362E-02, 5.688E-02, 5.173E-02 , 4.422E-02, 3.503E-02, 2.949E-02 , 2.577E-02, 2.307E-02, 1.940E-02 , 1.703E-02, 1.363E-02, 1.183E-02 }; Double_t en[kN] = { 1.00000E-03, 1.50000E-03, 2.00000E-03 , 3.00000E-03, 4.00000E-03, 5.00000E-03 , 6.00000E-03, 8.00000E-03, 1.00000E-02 , 1.50000E-02, 2.00000E-02, 3.00000E-02 , 4.00000E-02, 5.00000E-02, 6.00000E-02 , 8.00000E-02, 1.00000E-01, 1.50000E-01 , 2.00000E-01, 3.00000E-01, 4.00000E-01 , 5.00000E-01, 6.00000E-01, 8.00000E-01 , 1.00000E+00, 1.25000E+00, 1.50000E+00 , 2.00000E+00, 3.00000E+00, 4.00000E+00 , 5.00000E+00, 6.00000E+00, 8.00000E+00 , 1.00000E+01, 1.50000E+01, 2.00000E+01 }; return Interpolate(energyMeV,en,mu,kN); } //_____________________________________________________________________________ Double_t AliTRDsim::Interpolate(Double_t energyMeV , Double_t *en, Double_t *mu, Int_t n) { // // Interpolates the photon absorbtion cross section // for a given energy . // Double_t de = 0; Int_t index = 0; Int_t istat = Locate(en,n,energyMeV,index,de); if (istat == 0) { return (mu[index] - de * (mu[index] - mu[index+1]) / (en[index+1] - en[index] )); } else { return 0.0; } } //_____________________________________________________________________________ Int_t AliTRDsim::Locate(Double_t *xv, Int_t n, Double_t xval , Int_t &kl, Double_t &dx) { // // Locates a point (xval) in a 1-dim grid (xv(n)) // if (xval >= xv[n-1]) return 1; if (xval < xv[0]) return -1; Int_t km; Int_t kh = n - 1; kl = 0; while (kh - kl > 1) { if (xval < xv[km = (kl+kh)/2]) kh = km; else kl = km; } if (xval < xv[kl] || xval > xv[kl+1] || kl >= n-1) { printf("Locate failed xv[%d] %f xval %f xv[%d] %f!!!\n" ,kl,xv[kl],xval,kl+1,xv[kl+1]); exit(1); } dx = xval - xv[kl]; return 0; }