First Use of High Charge States for Mass Measurements of Short-Lived Nuclides in a Penning Trap

摘要

Penning trap mass measurements of short-lived nuclides have been performed for the first time with highly charged ions, using the TITAN facility at TRIUMF. Compared to singly charged ions, this provides an improvement in experimental precision that scales with the charge state q. Neutron-deficient Rb isotopes have been charge bred in an electron beam ion trap to q = 8- 12+ prior to injection into the Penning trap. In combination with the Ramsey excitation scheme, this unique setup creating low energy, highly charged ions at a radioactive beam facility opens the door to unrivaled precision with gains of 1-2 orders of magnitude. The method is particularly suited for short-lived nuclides such as the super-allowed β emitter ~(74)Rb (T_(1/2) = 65 ms). The determination of its atomic mass and an improved Q_(ec) value are presented.