Search for the decay of nature's rarest isotope Ta 180m
Ta180m is the rarest naturally occurring quasistable isotope and the longest lived metastable state which is known. Its possible decay via the β- or the electron capture channel has never been observed. This article presents a search for the decay of Ta180m with an ultralow background Sandwich HPGe γ spectrometry setup in the HADES underground laboratory. No signal is observed and improved lower partial half-life limits are set with a Bayesian analysis to 5.8×1016yr for the β- channel and 2.0×1017yr for the electron capture channel (90 % credibility). The total half-life of Ta180m is longer than 4.5×1016yr. This is more than a factor of two improvement compared to previous searches.
|Journal||Physical Review C|
Lehnert, B., Hult, M., Lutter, G., & Zuber, K. (2017). Search for the decay of nature's rarest isotope Ta 180m. Physical Review C, 95(4). doi:10.1103/PhysRevC.95.044306