Upgrade of the rf System for RIKEN Ring Cyclotron, RRC

Abstract

The rf system of the RIKEN Ring Cyclotron (RRC) was upgraded in order to increase the acceleration voltage at 18.25 MHz operation by remodeling its rf controllers and cavity resonators. As a result, the maximum gap voltage at 18.25 MHz improved from about 80 kV to more than 150 kV. The beam intensity of ²³⁸U for the RIBF was increased to 94 pnA in the fiscal 2019 by overcoming the beam intensity limitation due to the space charge effect. It is ready to further increase the beam intensity in the near future.