Near-yrast discrete line γ-ray spectroscopy of 159Er and 160Er to I > 40h/2π

High-spin states in 159Er and 160Er have been populated using the 116Cd + 48Ca reaction at a 48Ca bombarding energy of 210 MeV. Gamma rays were detected in an array of six escape-suppressed germanium spectrometers and a 50 element BGO multiplicity and summed energy detector. Decay scheme and angular correlation data for these nuclei were deduced from the γ-γ-BGO coincidence data. In 159Er the yrast band has been identified up to Isup(π) = 89/2+ and three side bands have been observed to 69/2-(77/2-), 43/2+ and 51/2-(59/2-). In 160Er the lowest energy positive-parity band has been observed up to 38+(40+) and the two lowest energy negative-parity side bands up to 40-(44-) and 39-(41-). The ground state level sequence has been observed up to (28+). The spin and parity of the low-lying states (I < 20 h/2π) in the bands observed in 160Er were established by measuring γ-ray angular distributions and internal conversion coefficients following the 148Nd(16O, 4n) reaction at a beam energy of 80 MeV. (author)