Study of One-nucleon Transfer Reactions

The structure of nuclei away from the line of stability and near the driplines in the nuclear chart has been of huge interest since the arrival of radioactive ion beam facilities. The properties of nuclei evolve as a function of proton and neutron numbers and understanding the mechanisms behind this is one of the keys to explaining the strong nuclear force. Single-nucleon transfer reactions using deuteron targets are powerful probes of nuclear structure when the emitted proton or neutron is measured with high fidelity.

A variety of structure phenomena are observed in the beryllium isotopes marking them particularly attractive for nuclear structure studies. The structure of ¹³Be offers insights into the N=8 shell gap, the nature of the Borromean nucleus ¹⁴Be, the influence of the continuum, and the nature of neutron drip-line nuclei. However, despite the significant number of experiments performed over the last three decades, the energies and ordering of the low-lying resonances are less certain.

A ¹²Be(d,p)¹³Be transfer reaction was performed in inverse kinematics at ISAC II at TRIUMF. The ¹²Be beam at 9.5 MeV/u interacted with the novel IRIS solid D₂ target, and ejectiles and recoils were detected in an annular silicon detector array and two ΔE - E telescopes, respectively. A Q-value plot showing the population of resonances in the ¹³Be continuum was obtained, and it was fitted using GEANT4 simulations in combination with Bayesian optimization. An angular distribution of the lowest-lying strength in ¹³Be was obtained, and it was fitted with DWBA calculations using different combinations of optical model potentials. Results from this work will be presented here, along with interpretations of five previous works performed on ¹³Be, in comparison with our data.

The NEXT detector is a novel, high precision, segmented neutron detector which offers excellent position and timing resolution. It uses a pulse shape discriminating plastic scintillator, which is crucial in identifying neutrons from a gamma-ray background in reaction experiments. A ²⁰Ne(d,n)²¹Na proton transfer reaction was performed at ReA6 at NSCL to benchmark this detector for reaction experiment studies. The details and preliminary results of this experiment will also be presented.