Superconducting Linac Booster for Super-Heavy Element Experiments at RIKEN Radioactive Isotope Beam Factory

Abstract The Rikagaku Kenkyūjo (RIKEN) heavy-ion linac was upgraded by introducing a new super-conducting linac-booster to advance the super-heavy elements synthesis program beyond nihonium at the RIKEN Radioactive Isotope Beam Factory (RIBF). The total acceleration voltage was upgraded from 25 MV with 12 room temperature drift-tube-linacs (DTLs) to 39 MV by introducing a superconducting linac booster, SRILAC. The upgrade of the beam intensity is realized by a newly constructed superconducting electron-cyclotron resonance ion source (SC-ECRIS). The construction of SRILAC and the SC-ECRIS started in FY2017. After the hardware installation and commissioning, the first beam acceleration test was successfully conducted at the end of FY2019, and user beam service was started in FY2020. This article provides an overview of the upgrade and its present performance.