Li Neutron-unbound States using a Compact Detector System*

The study of neutron-unbound states requires measuring properties of the emitted charged fragments and neutrons, which may be made more complicated if the emitted charged particles are in a bound excited state. This is because the de-excitation of these bound excited states emit gamma rays, which causes an energy misassignment of the neutron-unbound states. An additional detection system is therefore required to measure these gamma rays. The MoNA collaboration recently ran an experiment to determine if the 0⁺ bound excited state of ¹²Be is populated following neutron emission from ¹³Be rather than the 0⁺ ground state. There were several secondary beams available in the experiment, including ¹¹Li, ¹⁵B, and ¹⁴Be, the latter of which was used for the main experiment. The neutron-unbound states in this experiment were reconstructed by using a stack of five silicon PINs and one CsI detector to measure the energy of the charged fragment, the MoNA-LISA detector to measure the momentum of neutrons, and the CAESAR detector to measure gamma rays. A reconstruction of ¹⁰Li neutron-unbound states produced by neutron knockout with the ¹¹Li beam may be used as a test of this experimental setup. The comparison of this data with prior experimental results will be presented.