Overview of Fragment Separator Superconducting Magnets in the Facility for Rare Isotope Beams

Abstract

In 2022, the Facility for Rare Isotope Beams (FRIB) has been established as one of the world-class user facilities for the study of physics of atomic nuclei. The key feature is to provide a variety of nuclei with an energy of 200 MeV per nucleon with a beam power up to 400 kW in the FRIB driver linear accelerator (linac). The linac driven beam experiences a series of the FRIB fragment separator, consisting of the hot-cell target hall, vertical pre-separator, and A1900 fragment separator, which eventually allows a successful delivery of the final rare isotope of interest into the experimental vaults. The superconducting magnet commissioning with heavy ion beams has been progressed by the completion of each area sequentially, and finally the first rare isotope of selenium-84 was successfully produced with the FRIB target using a krypton-86 primary beam, demonstrating FRIB's capability for scientific discovery. This paper presents the FRIB superconducting magnet scope, series fabrication and installation, and the energization at the FRIB premises. The discussion deals with the major test results, and also suggests the significance of advanced technology development for the FRIB next-generation superconducting magnet.