Phys.Rev. C 104, 024306 (2021)

Y.Shigekawa, A.Yamaguchi, K.Suzuki, H.Haba, T.Hiraki, H.Kikunaga, T.Masuda, S.Nishimura, N.Sasao, A.Yoshimi, K.Yoshimura

Estimation of radiative half-life of ^229mTh by half-life measurement of other nuclear excited states in ²²⁹Th

RADIOACTIVITY ²³³Th(α)[source chemically purified by anion-exchange chromatography]; measured Eα, Iα, Eγ, Iγ, αγ-coin, half-life of levels in ²²⁹Th by αγ(t) using a passivated implanted planar Si (PIPS) detector for α detection, and LaBr₃(Ce) detector for γ radiation. ²²⁹Th; deduced levels, J, π, B(M1), B(E2). Comparison of transition probabilities with estimates from the Alaga rule for intraband transitions, and with previous experimental level T_1/2. ^229mTh; deduced radiative half-life of the 8.28-eV isomer from B(M1) estimated from Alaga Rule for the interband transitions, and compared with experimental and other theoretical values.

doi: 10.1103/PhysRevC.104.024306