diff --git a/src/PrimaryGeneratorAction.cc b/src/PrimaryGeneratorAction.cc
index aacec9b..6e0b420 100644
--- a/src/PrimaryGeneratorAction.cc
+++ b/src/PrimaryGeneratorAction.cc
@@ -79,7 +79,7 @@ void PrimaryGeneratorAction::GeneratePrimaries(G4Event* anEvent)
   // This function is called at the begining of event
 
   G4double rand =  0;
-  while(rand > 1 || rand < 0)
+  while(rand > 1 || rand <= 0)
       rand = G4INCL::Random::shoot();
   partEnergy = rand*(maxPartEnergy-minPartEnergy)+minPartEnergy;