Search for alpha decay of natural Europium

摘要

The indication for the a decay of Eu-151 (Q alpha = 1.964 MeV) with the half-life T-1/2(alpha) = 5(-3)(+11) x 10(18) yr has been observed for the first time with the help of a low background CaF2(Eu) crystal scintillator (mass of 370 g) in measurement at the Gran Sasso National Laboratories of the INFN during 7426 h. In a conservative approach the lower limit on the half-life of Eu-151 has been established as T-1/2(alpha) >= 1.7 x 10(18) yr at 68% C.L. (c) 2007 Elsevier B.V. All rights reserved.