+ // need to correct here for the depth of the shower start point (TDR p 127) ?
+
+ Float_t energy = fEmcRecPoint->GetEnergy() ;
+ Float_t para = 0.925 ;
+ Float_t parb = 6.52 ;
+
+ TVector3 localpos ;
+ fEmcRecPoint->GetLocalPosition(localpos) ;
+
+ AliPHOSGeometry * geom = AliPHOSGeometry::GetInstance() ;
+ Float_t radius = geom->GetIPtoOuterCoverDistance() + geom->GetOuterBoxSize(1) ;
+ Float_t incidencephi = TMath::ATan(localpos.X() / radius) ;
+ Float_t incidencetheta = TMath::ATan(localpos.Z() / radius) ;
+
+ Float_t depthx = - ( para * TMath::Log(energy) + parb ) * TMath::Sin(incidencephi) ;
+ Float_t depthz = - ( para * TMath::Log(energy) + parb ) * TMath::Sin(incidencetheta) ;
+