Nuclear Data Sheets for A=233

Abstract

The present evaluation of the known A=233 nuclides (233Fr, 233Ra, 233Ac, 233Th, 233Pa, 233U, 233Np, 233Pu, 233Am, 233Cm) and 233Bk represents an update and revision, after 15 years of the previous evaluation of A=233 published by B. Singh and J.K. Tuli (2005Si15). Laboratory identification of 233Bk nuclide is still considered as tentative. Various decay and reaction data are evaluated and compared. Adopted data, levels, gammas, level half-lives, spins, parities, and configuration assignments are provided. For 233Fr, 233Ra, 233Ac, 233Pu, 233Am and 233Cm, information is available for the respective ground states only. The decay schemes from β− decays of 233Fr and 233Ra, and from ε decay of 233Am and 233Cm are unknown, while those from β− decay of 233Ac, and from ε decay of 233Np are considered incomplete. The α decay of 237Np to 233Pa has been studied in detail by many investigators, yet the decay scheme is considered incomplete as several very low-energy transitions are involved, without the knowledge of their intensities, resulting in mismatch of directly measured α feedings and those deduced from γ-transition intensity balances. The decay schemes from α decays of 237Am, 237Cm and 237Cf to respective A=233 daughters are considered incomplete. Particle-transfer and high-spin data are available for 233Th, 233Pa and 233U nuclei, which remain the most extensively studied in this mass chain. However, data for half-lives for the excited states are available only for one level in 233Pa, and for five levels in 233U, thus limiting the knowledge of reduced transition probabilities in this mass chain.