Efficient Fragment Separator for High Energy Secondary Radioactive Beams

Radioactive beams have a major impact on studies of nuclear structure and nuclear physics far from stability. The production of such isotopes is an important component of broad scientific programs at next generation facilities such as the Facility for Rare Isotope Beams (FRIB). To maximize the science reach, the secondary fragments must be filtered from the radioactive beams. Currently, a three-stage magnetic separator is used for beam purification. However, its filtering capability is in most cases not sufficient for performing experiments. In response to this problem, RadiaBeam Systems proposes to design and build a cost-efficient RF kicker cavity as an addition to the existing separator. The device will be capable of deflecting 120 MeV/u ions with charge-to-mass ratio of ½ by up to 13 mm in 3 m distance. We will implement a direct drive of the cavity with efficient solid-state RF sources without couplers, allowing up to 70% wall-plug power efficiency. In Phase I, we plan to perform the RF design, conceptual engineering and beam dynamics study of the cavity and the power supply system that will satisfy the required parameters. We will optimize the electrode shape so that the cavity can produce the required 300 kV kick with minimal power losses and peak fields of ~1 Kilpatrick. A prototype of a solid-state RF module for the direct-drive technique will be built and tested. The results of this work will be of immediate benefit to the FRIB facility. In addition, a similar buncher could be used at ATLAS for purifying in-flight produced rare isotope beams. RF fragment separators are also of interest for mass-spectrometry as they can provide very precise isotope separation, which is critical for security, defense, and environmental applications. Finally, the secondary product of the proposed project will be a solid-state RF source and direct-drive technology that will be applicable for both accelerator facilities and to the industrial and defense community.