1. Physics Department, Nuclear Physics Lab, Aristotle University of Thessaloniki, Thessaloniki, Greece
2. Biology Department, Division of Botany, Aristotle University of Thessaloniki, Thessaloniki, Greece
3. Geology Depatment, Aristotle University of Thessaloniki, Thessaloniki, Greece
4. Physics Department, Faculty of Science, University of Novi Sad, Novi Sad, Serbia
5. Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, Dubna, Russia