Orbital electron capture and beta(+) decay of H-like Pr-141 ions

For the first time the electron capture and beta(+) decay rates of H-like Pr-140 ions have been measured at the FRS-ESR facility by using the Schottky noise technique. The H-like Pr-140(58+) decay rate was found to be larger by a factor of 1.5 than in the case of neutral atom. This non-intuitive result can be explained by taking into account hyperfine splitting of nuclear levels in the decaying nuclei and the conservation law of the total angular momentum of the system.