Corrected calculation of the step size

diff --git a/TRD/AliTRDv1.cxx b/TRD/AliTRDv1.cxx
index ed68793f59090be188852333576684d7b5b1fc18..44c2ed2dd740c08fadb368668217c121c69332d9 100644 (file)
--- a/TRD/AliTRDv1.cxx
+++ b/TRD/AliTRDv1.cxx
@@ -675,9 +675,11 @@ void AliTRDv1::StepManagerGeant()
                                                pp = kPrim * kPlateau;
           }
 
-          stepSize = 1./gRandom->Poisson(pp);
-                                       gMC->SetMaxStep(stepSize);
-                               }
+         Int_t nsteps = 0;
+         do {nsteps = gRandom->Poisson(pp);} while(!nsteps);
+          stepSize = 1./nsteps;
+         gMC->SetMaxStep(stepSize);
+       }
       }
     }
   }