Index: trunk/MagicSoft/Mars/mhist/MHMcCollectionArea.cc
===================================================================
--- trunk/MagicSoft/Mars/mhist/MHMcCollectionArea.cc	(revision 905)
+++ trunk/MagicSoft/Mars/mhist/MHMcCollectionArea.cc	(revision 929)
@@ -162,5 +162,5 @@
             const Double_t r2  = fHistSel->GetYaxis()->GetBinLowEdge(iy+1);
 
-            const Double_t A   = kPI * (r2*r2 - r1*r1);
+            const Double_t A   = TMath::Pi() * (r2*r2 - r1*r1);
 
             const Double_t eff = fHistSel->GetCellContent(ix, iy);