Decay of 159Dy: L-subshell X-ray fluorescence and Coster-kronig yields at Z = 65; branching ratio, and K-conversion of the 58 keV transition in 159Tb

Abstract

Ultra-high resolution Ge(Li) and Si(Li) detectors have been used to study L-subshell X-ray fluorescence and Coster-Kronig yields in Tb from the EC decay of carrier-free 159Dy. From singles and L X-ray spectra in coincidence with Kα1 and Kα2 X-rays, the following L-subshell quantities were obtained: ω3 = 0.188±0.016, ω2 = 0.160±0.018, f23 = 0.090±0.014, v1 = 0.29±0.08, v2 = 0.177±0.019, s2 = 0.204±0.024, s3 = 0.170±0.024, and ωKL = 0.184 ±0.016. Corrections for nuclear cascading were made experimentally using an L X-ray spectrum gated by Kβ X-rays. Angular correlation effects were taken into account. Taking a theoretical value of s1 = 0.270, the present experiment allows estimates to be made of the following L1 subshell quantities: ω1 = 0.18±0.04, ƒ12 = 0.41±0.36 and ƒ13 = 0.43±0.28. K X-ray spectra in coincidence with K X-rays and with the 58.0 keV γ-ray were taken to determine the EC branching to the 58.0 keV level (26.8±1.4%) and the K-conversion coefficient of the 58.0 keV transition, αK = 9.3±0.5, which agrees with the theoretical value for an M1 + 1.4% E2 transition.