Inverse-kinematics one-neutron pickup with fast rare-isotope beams

Abstract

New measurements and reaction model calculations are reported for single neutron pickup reactions onto a fast \nuc{22}{Mg} secondary beam at 84 MeV per nucleon. Measurements were made on both carbon and beryllium targets, having very different structures, allowing a first investigation of the likely nature of the pickup reaction mechanism. The measurements involve thick reaction targets and $\gamma$-ray spectroscopy of the projectile-like reaction residue for final-state resolution, that permit experiments with low incident beam rates compared to traditional low-energy transfer reactions. From measured longitudinal momentum distributions we show that the $\nuc{12}{C} (\nuc{22}{Mg},\nuc{23}{Mg}+γ)X$ reaction largely proceeds as a direct two-body reaction, the neutron transfer producing bound \nuc{11}{C} target residues. The corresponding reaction on the \nuc{9}{Be} target seems to largely leave the \nuc{8}{Be} residual nucleus unbound at excitation energies high in the continuum. We discuss the possible use of such fast-beam one-neutron pickup reactions to track single-particle strength in exotic nuclei, and also their expected sensitivity to neutron high-$\ell$ (intruder) states which are often direct indicators of shell evolution and the disappearance of magic numbers in the exotic regime.

arXiv comment8 pages, 5 figures

References in corpus (2)

• Quantum Monte Carlo Calculations of Light Nuclei
• In-beam gamma-ray spectroscopy at the proton dripline: 23Al

Cited by in corpus (5)

• Invariant-mass spectroscopy of ${}^{18}$Ne, ${}^{16}$O, and ${}^{10}$C excited states formed in neutron transfer reactions
• Spectroscopy of ${}^{35}$P using the one-proton knockout reaction
• Exploiting dissipative reactions to perform in-beam $\gamma$-ray spectroscopy of the neutron-deficient isotopes \nuc{38,39}{Ca}
• Intermediate-energy inverse-kinematics one-proton pickup reactions on neutron-deficient $fp$-shell nuclei
• News on the nuclear structure of neutron-rich nuclei at and beyond N=28