Reduction of contaminants originating from primary beam by improving the beam stoppers in GARIS-II

Abstract

Two independent beam stoppers have been developed for improving the beam separation of the gas-filled recoil ion separator GARIS-II. Performance evaluation of these supplemental beam stoppers was performed by using the 208Pb (18O,3n)223Th reaction. A160-fold enhancement of the signal-to-noise ratio at the GARIS-II focal plane was observed.