The ReA post-accelerator of the Facility for Rare Isotope Beams (FRIB) employs an Electron-Beam Ion Trap (EBIT) as a charge breeder to reaccelerate RIB up ~10 MeV/u. The ReA-EBIT uses a Pierce-type electron gun, partially magneto-immersed with a Ba-dispenser cathode, to produce an electron current of ~600 mA. It corresponds to a current density of ~340 A/cm^2 in the ion trap and a trap capacity of 10^10 charges, which can be insufficient to handle future high RIB rates. To increase the trap capacity, a High-Current Electron-Beam Ion Source (HCEBIS) has been built based on the TestEBIS obtained from BNL. By using a 4-A electron beam launched from a LaB6 convex cathode immersed in a magnetic field, a current density of 298 A/cm^2 and a maximum capacity of 2.4×10^11 charges are predicted. In parallel, the ReA-EBIT e-gun is being upgraded. A new insert is being fabricated to include a large-area dispenser cathode to achieve higher electron-beam current and density. A 2-A electron-beam is projected to reach a capacity of 5×10^10 charges. In simulations a current density of 432 A/cm^2 was obtained in the trap region. This paper presents the status of the HCEBIS and the ReA-EBIT upgrade.

An electron beam ion source (EBIS) was considered as a charge breeder for rare isotopes produced from isotope separation on-line (ISOL) system of the heavy ion accelerator RAON in Korea. The off-line installation of the RAON EBIS was conducted at the Korea University, Sejong from 2017 to 2020. A lot of effort went into getting very low vacuum pressure of around 1E-10 torr at the breeding region adopting cryopumps and getter pumps as well as vacuum-firing the chambers. In order to find and align the central magnetic field lines of the solenoids, we used a gimbal mount for a hall probe with rotation, tilt, and translation functions. With the help of four sets of steering coils around the drift tube chamber, we successfully transport electron beam of 2 A at a magnetic field of 6 T producing charge bred ions from the residual gas. After confirming the performance of our EBIS system at the off-line site, we moved it to RAON accelerator site at Shindong and started the on-line installation from 2021. Cesium test ion beam was used for the first charge breeding experiment showing a relative abundance of Cs27+ ions more than 20 % with electron beam current of 1 A in breeding time of 40 ms.