Progress towards the EDM³ instrument at FRIB Part 1: Ionization and mass separation

The study of radioactive molecules receives increasing attention due to their enhanced sensitivity to fundamental symmetry violations and Beyond Standard Model physics. In particular, ²²⁵RaF has been proposed as powerful probe due to its enhanced Schiff-moment. While the principle advantage of such systems is known for more than 30 years [1], the progress in the field relies on the development of novel instruments and the availability of suitable radioisotopes. At the Facility for Rare Isotope Beams (FRIB), the latter is being addressed by development of isotope harvesting techniques [2].

Within a series of two contributions, we introduce the in-design FRIB-EDM³ instrument. The first contribution covers ionization and mass-separation of harvested radioisotopes; the second contribution is focused on neutralization of molecular ions and their embedding in a solid noble gas matrix [3].

The efficient ionization of harvested radioisotopes from aqueous phase is pursued with a spray-ionization method [4]. Subsequently, the molecular ion beam is analyzed by mass-to-charge ratio by a quadrupole mass filter. Octupole ion guides serve to minimize losses during the differential pumping stages. We will report on the progress of the instrument’s construction and its simulation-aided design.