+}
+//______________________________________________________________________________________
+TH2S* AliTRDCalibraVdriftLinearFit::GetLinearFitterHistoForce(Int_t detector)
+{
+ //
+ // return pointer to TH2F histo
+ // if NULL create a new histo if it doesn't exist allready
+ //
+ if (fLinearFitterHistoArray.UncheckedAt(detector))
+ return (TH2S*)fLinearFitterHistoArray.UncheckedAt(detector);
+
+ // if we are forced and TLinearFitter doesn't yes exist create it
+
+ // new TH2F
+ TString name("LFDV");
+ name += detector;
+ name += "version";
+ name += fVersion;
+
+ TH2S *lfdv = new TH2S((const Char_t *)name,(const Char_t *) name
+ ,36,-0.9,0.9,48
+ ,-1.2,1.2);
+ lfdv->SetXTitle("tan(phi_{track})");
+ lfdv->SetYTitle("dy/dt");
+ lfdv->SetZTitle("Number of clusters");
+ lfdv->SetStats(0);
+ lfdv->SetDirectory(0);
+
+ fLinearFitterHistoArray.AddAt(lfdv,detector);
+ return lfdv;