In the whole landscape of atomic nuclei, $^{ 229}$Th is currently the only known nucleus which could allow for the development of a nuclear-based frequency standard, as it possesses an isomeric state of just 7.6 eV energy above the ground state. The 3+ charge state is of special importance in this context, as Th$^{ 3+}$ allows for a simple laser-cooling scheme. Here we emphasize the direct extraction of triply-charged $^{ 229}$Th from a buffer-gas stopping cell. This finding will not only simplify any future approach of $^{ 229}$Th ion cooling, but is also used for thorium-beam purification and in this way provides a powerful tool for the direct identification of the $^{ 229}$Th isomer to ground state nuclear transition.
Categories: physics.ins-det nucl-ex