weightThetaCerenkov += fPhotCkov[i]*fPhotWei[i];
wei += fPhotWei[i]; //collect weight as sum of all candidate weghts
- sigma2 += 1./Sigma2(fPhotCkov[i],fPhotPhi[i]);
+ sigma2 += 1./fParam->Sigma2(fTrkDir.Theta(),fTrkDir.Phi(),fPhotCkov[i],fPhotPhi[i]);
}
}//candidates loop
return (Double_t)(locMax*fDTheta+0.5*fDTheta); //final most probable track theta ckov
}//HoughResponse()
//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-Double_t AliHMPIDRecon::Sigma2(Double_t ckovTh, Double_t ckovPh)const
-{
-// Analithical calculation of total error (as a sum of localization, geometrical and chromatic errors) on Cerenkov angle for a given Cerenkov photon
-// created by a given MIP. Fromulae according to CERN-EP-2000-058
-// Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
-// dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]
-// MIP beta
-// Returns: absolute error on Cerenkov angle, [radians]
-
- TVector3 v(-999,-999,-999);
- Double_t trkBeta = 1./(TMath::Cos(ckovTh)*fParam->GetRefIdx());
-
- if(trkBeta > 1) trkBeta = 1; //protection against bad measured thetaCer
- if(trkBeta < 0) trkBeta = 0.0001; //
-
- v.SetX(SigLoc (ckovTh,ckovPh,trkBeta));
- v.SetY(SigGeom(ckovTh,ckovPh,trkBeta));
- v.SetZ(SigCrom(ckovTh,ckovPh,trkBeta));
-
- return v.Mag2();
-}
-//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-Double_t AliHMPIDRecon::SigLoc(Double_t thetaC, Double_t phiC,Double_t betaM)const
-{
-// Analithical calculation of localization error (due to finite segmentation of PC) on Cerenkov angle for a given Cerenkov photon
-// created by a given MIP. Fromulae according to CERN-EP-2000-058
-// Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
-// dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]
-// MIP beta
-// Returns: absolute error on Cerenkov angle, [radians]
-
- Double_t phiDelta = phiC - fTrkDir.Phi();
-
- Double_t sint = TMath::Sin(fTrkDir.Theta());
- Double_t cost = TMath::Cos(fTrkDir.Theta());
- Double_t sinf = TMath::Sin(fTrkDir.Phi());
- Double_t cosf = TMath::Cos(fTrkDir.Phi());
- Double_t sinfd = TMath::Sin(phiDelta);
- Double_t cosfd = TMath::Cos(phiDelta);
- Double_t tantheta = TMath::Tan(thetaC);
-
- Double_t alpha =cost-tantheta*cosfd*sint; // formula (11)
- Double_t k = 1.-fParam->GetRefIdx()*fParam->GetRefIdx()+alpha*alpha/(betaM*betaM); // formula (after 8 in the text)
- if (k<0) return 1e10;
- Double_t mu =sint*sinf+tantheta*(cost*cosfd*sinf+sinfd*cosf); // formula (10)
- Double_t e =sint*cosf+tantheta*(cost*cosfd*cosf-sinfd*sinf); // formula (9)
-
- Double_t kk = betaM*TMath::Sqrt(k)/(fParam->GapThick()*alpha); // formula (6) and (7)
- Double_t dtdxc = kk*(k*(cosfd*cosf-cost*sinfd*sinf)-(alpha*mu/(betaM*betaM))*sint*sinfd); // formula (6)
- Double_t dtdyc = kk*(k*(cosfd*sinf+cost*sinfd*cosf)+(alpha* e/(betaM*betaM))*sint*sinfd); // formula (7) pag.4
-
- Double_t errX = 0.2,errY=0.25; //end of page 7
- return TMath::Sqrt(errX*errX*dtdxc*dtdxc + errY*errY*dtdyc*dtdyc);
-}
-//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-Double_t AliHMPIDRecon::SigCrom(Double_t thetaC, Double_t phiC,Double_t betaM)const
-{
-// Analithical calculation of chromatic error (due to lack of knowledge of Cerenkov photon energy) on Cerenkov angle for a given Cerenkov photon
-// created by a given MIP. Fromulae according to CERN-EP-2000-058
-// Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
-// dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]
-// MIP beta
-// Returns: absolute error on Cerenkov angle, [radians]
-
- Double_t phiDelta = phiC - fTrkDir.Phi();
-
- Double_t sint = TMath::Sin(fTrkDir.Theta());
- Double_t cost = TMath::Cos(fTrkDir.Theta());
- Double_t cosfd = TMath::Cos(phiDelta);
- Double_t tantheta = TMath::Tan(thetaC);
-
- Double_t alpha =cost-tantheta*cosfd*sint; // formula (11)
- Double_t dtdn = cost*fParam->GetRefIdx()*betaM*betaM/(alpha*tantheta); // formula (12)
-
-// Double_t f = 0.00928*(7.75-5.635)/TMath::Sqrt(12.);
- Double_t f = 0.0172*(7.75-5.635)/TMath::Sqrt(24.);
-
- return f*dtdn;
-}//SigCrom()
-//++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-Double_t AliHMPIDRecon::SigGeom(Double_t thetaC, Double_t phiC,Double_t betaM)const
-{
-// Analithical calculation of geometric error (due to lack of knowledge of creation point in radiator) on Cerenkov angle for a given Cerenkov photon
-// created by a given MIP. Formulae according to CERN-EP-2000-058
-// Arguments: Cerenkov and azimuthal angles for Cerenkov photon, [radians]
-// dip and azimuthal angles for MIP taken at the entrance to radiator, [radians]
-// MIP beta
-// Returns: absolute error on Cerenkov angle, [radians]
-
- Double_t phiDelta = phiC - fTrkDir.Phi();
-
- Double_t sint = TMath::Sin(fTrkDir.Theta());
- Double_t cost = TMath::Cos(fTrkDir.Theta());
- Double_t sinf = TMath::Sin(fTrkDir.Phi());
- Double_t cosfd = TMath::Cos(phiDelta);
- Double_t costheta = TMath::Cos(thetaC);
- Double_t tantheta = TMath::Tan(thetaC);
-
- Double_t alpha =cost-tantheta*cosfd*sint; // formula (11)
-
- Double_t k = 1.-fParam->GetRefIdx()*fParam->GetRefIdx()+alpha*alpha/(betaM*betaM); // formula (after 8 in the text)
- if (k<0) return 1e10;
-
- Double_t eTr = 0.5*fParam->RadThick()*betaM*TMath::Sqrt(k)/(fParam->GapThick()*alpha); // formula (14)
- Double_t lambda = 1.-sint*sint*sinf*sinf; // formula (15)
-
- Double_t c1 = 1./(1.+ eTr*k/(alpha*alpha*costheta*costheta)); // formula (13.a)
- Double_t c2 = betaM*TMath::Power(k,1.5)*tantheta*lambda/(fParam->GapThick()*alpha*alpha); // formula (13.b)
- Double_t c3 = (1.+eTr*k*betaM*betaM)/((1+eTr)*alpha*alpha); // formula (13.c)
- Double_t c4 = TMath::Sqrt(k)*tantheta*(1-lambda)/(fParam->GapThick()*betaM); // formula (13.d)
- Double_t dtdT = c1 * (c2+c3*c4);
- Double_t trErr = fParam->RadThick()/(TMath::Sqrt(12.)*cost);
-
- return trErr*dtdT;
-}//SigGeom()
git://git.uio.no / u / mrichter / AliRoot.git / blobdiff