A New Measurement of the ¹⁰B(n, α)⁷Li Branching Ratio

To resolve a discrepancy in determinations of the ¹⁰B(n,α)⁷Li branching ratio, a new measurement has been made at the National Bureau of Standards (NBS). The measurement was made with a ¹⁰BF₃ gas proportional counter and monoenergetic 790-keV neutrons obtained at the NBS 3-MV Van de Graaff laboratory. A branching ratio of 0.66 ± 0.03 was obtained. This determination agrees with the measurements of Petree et al. and Davis et al.