The Beta-decay Paul Trap Mk IV: Design and commissioning

The Beta-decay Paul Trap is an open-geometry, linear trap used to measure the decays of 8Li and 8B to search for a tensor contribution to the weak interaction. In the latest 8Li measurement of Burkey et al. (2022), fi scattering was the dominant experimental systematic uncertainty. The Beta-decay Paul Trap Mk IV reduces the prevalence of fi scattering by a factor of 4 through a redesigned electrode geometry and the use of glassy carbon and graphite as electrode materials. The trap has been constructed and successfully commissioned with 8Li in a new data campaign that collected 2.6 million triple coincidence events, an increase in statistics by 30% with 4 times less fi scattering compared to the previous 8Li data set.