// calculates the impact coordinates on PHOS of a neutral particle
// emitted in the vertex vtx[3] with direction theta and phi in the ALICE global coordinate system
TVector3 p(TMath::Sin(theta)*TMath::Cos(phi),TMath::Sin(theta)*TMath::Sin(phi),TMath::Cos(theta)) ;
- TVector3 v(vtx[0],vtx[1],-vtx[2]) ;
+ TVector3 v(vtx[0],vtx[1],vtx[2]) ;
//calculate offset to crystal surface
Float_t * inthermo = fGeometryEMCA->GetInnerThermoHalfSize() ;
//____________________________________________________________________________
void AliPHOSGeometry::GetIncidentVector(const TVector3 &vtx, Int_t module, Float_t x,Float_t z, TVector3 &vInc) const {
//Calculates vector pointing from vertex to current poisition in module local frame
+ //Note that PHOS local system and ALICE global have opposite z directions
Global2Local(vInc,vtx,module) ;
- vInc.SetXYZ(vInc.X()+x,vInc.Y(),vInc.Z()+z) ;
+ vInc.SetXYZ(vInc.X()+x,vInc.Y(),vInc.Z()-z) ;
}