Lucrezia Terzi1, Martin Kalinowski2. 1. Belgian Nuclear Research Centre (SCK.CEN), Mol, Belgium. Electronic address: lucrezia.terzi@sckcen.be. 2. Provisional Technical Secretariat, Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization, Vienna International Centre, P.O. Box 1200, A-1400 Vienna, Austria.