CXXVII. Nuclear Reactions Produced by the Bombardment of Boron by Low Energy Alpha-Particles

Abstract

Boron targets have been bombarded by helium nuclei of energy between 1 and 2 mev. Resonances for production of gamma-rays and protons from the reactions ¹⁰B(αp)¹³C*, of protons from ¹⁰B(α, p)¹³C, and of deuterons from ¹⁰B(αd)¹²C were observed at 1·13, 1·24, 1·39, 1·51, 1·64, 1·68 and 1·83 mev. Resonances for neutrons from the ¹⁰B(αn)¹³N reaction were detected at 1·51, 1·64 and 2·05 mev. Angular distributions of the particles emitted were measured at 1·13, 1·51, 1·64, 1·68 and 1·83 mev and spins and parities of 4^-, 3^-, 4⁺, 4^- and 4⁺ tentatively assigned to the corresponding ¹⁴N levels. Spins and parities of 3/2^- and 5/2⁺ were confirmed for the second and third excited levels of ¹³C. Reaction cross sections and reduced level widths were obtained for alpha-particle energies of 1·51 and 1·64 mev. A resonance in the ¹¹B(αp)¹⁴C reaction was found at 1·58 mev alpha-particle energy.