“…In particular, Penning traps have been known to measure the mass of radioactive nuclei with a precision down to 10 −8 − 10 −9 [2,3,4,5,6]. Many such setups are already in operation [7,8,9,10,11,12,13] or under construction [14,15,16,17], showing both the need for measuring the ground-state properties of exotic nuclei and the success of the Penning trap in doing so. The review presented in [18] overviews recent ion traps and the masses they have allowed to measure.…”