1. INFN, Legnaro National LaboratoriesPadua Italy
2. Department of Physics and Earth SciencesUniversity of FerraraFerrara Italy
3. Department of GeologyUniversity of MarylandCollege Park MD USA
4. INFN, Ferrara SectionFerrara Italy
5. Department of Earth and Planetary Materials Science and Research Center for Neutrino Science, Graduate School of ScienceTohoku UniversitySendai Miyagi Japan