In-Beam α- and γ-Ray Spectroscopy for ²¹⁴Rn

Abstract

In-beam α- and γ-rays following a ²⁰⁸Pb(¹²C, α2n)²¹⁴Rn reaction were measured. A level scheme of ²¹⁴Rn is proposed up to the (8⁺) state. Two new long-range α-decays in ²¹⁴Rn were found to de-excite the (6⁺) and (8⁺) states. A half-life of the (8⁺) state was determined to be 7.3±1.5 ns from which the B(E2: 8→6) values was obtained to be 209±63 e²fm⁴. The reduced α-width γ_α² was also deduced as 3.2±1.0 keV for the α-decay from the (8⁺) state in ²¹⁴Rn to the ground state in ²¹²Po. Systematic trends of the B(E2: 8→6) and γ_α² values of the N=128 isotones, ²¹²Po, ²¹⁴Rn and ²¹⁶Ra, are discussed in terms of the simple shell model configurations.