Invariant-mass spectroscopy of ${}^{18}$Ne, ${}^{16}$O, and ${}^{10}$C excited states formed in neutron transfer reactions

Abstract

Neutron transfer reactions with fast secondary beams of ${}^{17}$Ne, ${}^{15}$O, and ${}^9$C have been studied with the HiRA and CAESAR arrays. Excited states of ${}^{18}$Ne, ${}^{16}$O, and ${}^{10}$C in the continuum have been identified using invariant-mass spectroscopy. The best experimental resolution of these states is achieved by selecting events where the decay fragments are emitted transverse to the beam direction. We have confirmed a number of spin assignments made in previous works for the negative-parity states of ${}^{18}$Ne. In addition we have found new higher-lying excited states in ${}^{16}$O and ${}^{18}$Ne, some of which fission into two ground-state ${}^8$Be fragments. Finally for ${}^{10}$C, a new excited state was observed. These transfer reactions were found to leave the remnant of the ${}^9$Be target nuclei at very high excitation energies and maybe associated with the pickup of a deeply-bound ${}^9$Be neutron.

21 pages, 18 figures