A 150 ms 10⁺ Isomer in¹⁴⁶Dy

In the course of systematic studies of very proton rich nuclei in the N≈82 region with Ni induced compound reactions, an unusually long-lived high spin isomer has been found. After in-and off-beam γ and conversion electron measurements, as γ excitation functions, γ and eγ coincidences, pulsed beam techniques and multi spectrum analyses of the residual activities, this isomer has been tentatively assigned to be a 10⁺ state in¹⁴⁶Dy, which decays into two 7^- states by E3 transitions. The half-life of the isomer has been measured to be 150±20ms. The isomer has been found to follow the β decay of the previously unknown 3.9 s isotope¹⁴⁶Ho. The mechanism of the appearance of such an isomer is discussed.