A preliminary study of direct 10Be2+ counting in AMS using the super-halogen anion BeF3−

Abstract The key to effective 10 Be measurements by AMS is to efficiently suppress the interference of the isobar 10 B and at the same time optimize 10 Be transmission. In this work, a new approach of measuring 10 Be by AMS has been studied. It uses the super-halogen anion of beryllium, BeF 3 − , which inherently suppresses 10 B interference by nearly 5 orders of magnitude because the accompanying BF 3 − anion is rarely formed. The resulting 10 B suppression factor is not as high as that achieved with energy degrader foils, but the 10 B and 10 Be separation in the final ionization detector was found to result in sufficient total 10 B suppression for 10 Be 2+ to be counted directly at ∼6 MeV energies. Although the stripping yield from 10 BeF 3 − to 10 Be 2+ is not as large as that from 10 BeO − , this inefficiency is compensated by avoiding the reduction in transmission due to charge fraction splitting and optical transmission losses after the degrader foil. This paper summarizes our first observation of the direct 10 Be 2+ counting approach using the 3 MV multi-element system at the Xi’an AMS.