Preparation for the measurement of the bound-state beta-decay of bare 205Tl ions at the ESRud

摘要

Bound-state beta-decay (βb) accompanied by the emission of a monochromatic antineutrino, was first predicted by Daudel et al [1] in 1947 and then discussed in detail by Bahcall [2]. The first direct observation of the bound-state beta decay (βb decay) was done in 1992 by Jung et al [3] with the use of bare 163Dy66+ ions stored in the heavy ion storage ring ESR at GSI. In the present study we aim at measuring the bound-state beta-decay rate of fully-ionized 205Tl, which is needed to determine the matrix element for the electron capture decay from the 2.3 keV excited state in 205Pb to the ground state of 205Tl. This matrix element is important for constraining of neutrino capture probability into the 2.3 keV state of 205Pb [4] and for modelling of the s-process [5] in the Hg-Pb region. The experiment proposal has been approved by the GSI program advisory panel. We aim at conducting the experiment in 2018, when the accelerator complex of GSI will restart its operation