Eur. Phys. J. A (2007) 34: 1-4
https://doi.org/10.1140/epja/i2007-10484-4

Letter

Evidence for a K^π = 1/2⁺ isomer in neutron-rich ¹⁸⁵Ta

¹ Quantum Beam Science Directorate, Japan Atomic Energy Agency, 619-0215, Kizugawa, Kyoto, Japan
² Advanced Science Research Center, Japan Atomic Energy Agency, 319-1195, Tokai, Ibaraki, Japan
³ Department of Energy Sciences, Tokyo Institute of Technology, 226-8502, Yokohama, Japan
⁴ Department of Research Reactor and Tandem Accelerator, Japan Atomic Energy Agency, 319-1195, Tokai, Ibaraki, Japan
⁵ Center for Nuclear Study, University of Tokyo, 351-0198, Wako, Saitama, Japan
⁶ Department of Physics, Kyushu University, 812-8581, Fukuoka, Japan

^* e-mail: shizuma.toshiyuki@jaea.go.jp

Received: 4 July 2007
Accepted: 18 September 2007
Published online: 4 October 2007

Abstract

Excited states in neutron-rich ¹⁸⁵Ta have been populated following the one-proton pickup reaction of ¹⁸⁶W(¹⁸O,¹⁹F). In-beam γ -rays were measured in coincidence with scattered particles detected by a high-resolution ΔE -E Si telescope for reaction channel selection. Several low-lying levels including a T _1/2 = 0.9(3) μs isomer at 406 keV have been identified. A spin assignment of I = 3/2 and the 1/2⁺[411] Nilsson configuration are given to the isomer in comparison with the level energy systematics and the isomer decay rates in the region.