Precise measurement of the half-life of 6¹Cu.

The decay characteristics of (61)Cu allow for a precise determination of its half-life. In order to search for a possible influence of the chemical environment on the decay rate, the half-life of (61)Cu in nickel and nickel-oxide was measured with high precision. The results show a small difference in the half-life that can be explained by the differences in electron density at the site of the nucleus. A discussion about the validity of the adopted value of the total angular momentum of the 656 keV state in (61)Ni is presented.