//
  G4VPhysicalVolume* volume = prePoint->GetTouchableHandle()->GetVolume();
  //test Aditya problem 16-08-20
  ///if (aStep->IsLastStepInVolume()) {
  ///  G4cout << "          last step in volume " << volume ->GetName() << "\n " << G4endl;    
  ///}
    if (aStep->GetPostStepPoint()->GetStepStatus() == fGeomBoundary) {
    G4cout << "          fGeomBoundary in volume " << volume ->GetName() << "\n " << G4endl;
    
  }