KoBRA Wien filter for low-energy RI beam production and recoil separation

Abstract

The Wien filter is one of the key components in ion optics to improve the mass separation performance. The KoBRA Wien filter will be installed at the low-energy beamline KoBRA of RAON in Korea. The specifications of the KoBRA Wien filter were determined based on the ion beams expected in the KoBRA beamline, especially, beam energies less than about 5 MeV/nucleon suitable for nuclear astrophysics experiments. The Wien filter is designed to have the maximum field intensities of 0.2 T for the magnetic field and 2.0 kV/mm for the electric field in the ±75(H)×±50(V)×2500(L)mm3 good-field region. Performance of the Wien filter was estimated by the ion optics calculations of the KoBRA beamline for 40Ar beams at 18.5 MeV/nucleon and 14O beams at 2.5 MeV/nucleon. The mass resolving powers are 42.65 and 517, respectively. Currently, the KoBRA Wien filter is being manufactured, and will perform a factory acceptance test.