Search for neutrino-less double beta decay of 48Ca by CaF2 scintillator

• DOI: 10.1016/j.nuclphysa.2003.10.015
• Publication Date: 2003-11-19T15:20:47Z
• Authors: I. Ogawa; R. Hazama; H. Miyawaki; S. Shiomi; N. Suzuki; Y. Ishikawa; G. Kunitomi; Y. Tanaka; M. Itamura; K. Matsuoka; S. Ajimura; T. Kishimoto; H. Ejiri; N. Kudomi; K. Kume; H. Ohsumi; K. Fushimi
• Keywords: 0103 physical sciences; 01 natural sciences; 7. Clean energy

Abstract A CaF 2 scintillation detector system (ELEGANT VI) has been operating at Oto Cosmo Observatory to study double beta decays of 48 Ca. No events were observed around the Q -value energy region after the analysis of 4.23 kg yr data. To derive the lower limit for the half-life of the neutrino-less double beta decay of 48 Ca, the expected number of background events in that energy region was estimated by a Monte Carlo simulation using the measured activities of 214 Bi and 220 Rn inside CaF 2 crystals. A new lower limit is obtained to be 1.4×10 22 yr at the 90% C.L. An experimental sensitivity is 5.9×10 21 yr at the 90% C.L.