Novel device to study double-alpha decay at the FRS Ion Catcher

A novel system has been developed to detect simultaneous double-alpha emission from purified and weightless sources. The system includes the collection of 224Ra low-energy recoils in purified helium buffer gas from the decay of 228Th. The recoil products are thermalized and collected in a cryogenic buffer gas cell and extracted into an RF-ion guide for mass selection. The mass-separated ions are implanted at low kinetic energy into a thin carbon foil placed between two large-area double-sided silicon strip detectors to observe correlated alpha-particle emission. The apparatus is described in detail, including insights into its experimental performance.