Observation of 186mTa

Unreported tantalum isomer 186mTa has been produced through the reaction 186W(n,p) by irradiation of natW with 14 MeV neutrons. The activity of 186mTa and 186Ta was measured using HPGe detectors and several X-γ as well as γ-γ coincidence arrangements. The 186mTa has been identified by means of measuring known γ rays from 186Ta β-decay. The half-life of 186mTa has been determined to be (1.5±0.1) min.