Development of Superconducting Linac-Booster for Low-beta Heavy Ions at RIKEN RIBF

Abstract

RIKEN Heavy-Ion Linac (RILAC) of Radioactive Isotope Beam Factory (RIBF) is undergoing an upgrade of its acceleration voltage to allow it to further investigate new super-heavy elements. In this project, a new superconducting (SC) booster linac has been developed and constructed. The SC-Linac consists of 10 TEM quarter-wavelength resonators (QWRs) made from pure niobium sheets which operate at 4 K. Recently we succeeded to develop high performance SC-cavities which satisfies the requirement as Q₀ of 1×10⁹ with its accelerating gradient of 6.8 MV/m with a wide margin. The QWRs were integrated to three cryomodules and installed to the beam line. This paper describes about design, fabrication, processing and testing of newly developed superconducting cavity and commissioning status after installation.