The magic nature of 132Sn explored through the single-particle states of 133Sn

• Published in: Nature (London) Vol. 465; no. 7297; pp. 454 - 457
• Main Authors: Jones, K. L., Adekola, A. S., Bardayan, D. W., Blackmon, J. C., Chae, K. Y., Chipps, K. A., Cizewski, J. A., Erikson, L., Harlin, C., Hatarik, R., Kapler, R., Kozub, R. L., Liang, J. F., Livesay, R., Ma, Z., Moazen, B. H., Nesaraja, C. D., Nunes, F. M., Pain, S. D., Patterson, N. P., Shapira, D., Shriner, J. F., Smith, M. S., Swan, T. P., Thomas, J. S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.05.2010; Nature Publishing Group
• Subjects: 639/638/263; 639/766/387; ATOMIC AND MOLECULAR PHYSICS; ATOMIC PHYSICS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CLOSURES; Exact sciences and technology; Humanities and Social Sciences; letter; MAGIC NUCLEI; multidisciplinary; NEUTRONS; Nuclear physics; NUCLEAR PHYSICS AND RADIATION PHYSICS; NUCLEAR STRUCTURE; NUCLEI; NUCLEONS; NUCLEOSYNTHESIS; Physics; PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; PRODUCTION; PROTONS; QUANTUM NUMBERS; R PROCESS; RARE GASES; Science; SHELL MODELS; Protons; Nuclear structure; Magic nuclei; Quantum numbers; Nuclear shell model; Nucleosynthesis; Neutrons; r process; Heavy element; Lifetime; Atomic nucleus; Magic number; Kinematics; Tin; Nucleons
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature09048

Nuclear magic Atomic nuclei have a shell structure that allows for 'magic' numbers of neutrons and protons, analogous to the noble gases in atomic physics. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for fundamental understanding of nuclear structure and nucleosynthesis. Using a nucleon transfer technique to add single neutrons to the short-lived tin isotope 132 Sn, to create the even-shorter-lived 133 Sn, Jones et al . have been able to confirm the closed-shell 'doubly magic' nature of 132 Sn. Measurements of the spectrum of quantum states available to the added neutron show that the characteristics of the 133 Sn nucleus are determined almost completely by this single neutron. This finding extends the validity of the shell model to neutron-rich nuclei, and provides a benchmark for predicting the properties of nuclei even farther from stability, including those involved in neutron-capture reactions in supernovae. Atomic nuclei have a shell structure that allows for 'magic numbers' of neutrons and protons, analogous to the noble gases in atomic physics. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for the fundamental understanding of nuclear structure and nucleosynthesis. Here, a nucleon-transfer technique has been used to measure the single-particle states of 133 Sn, revealing the highly magic nature of 132 Sn. Atomic nuclei have a shell structure 1 in which nuclei with ‘magic numbers’ of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important 2 , 3 , 4 , 5 for a fundamental understanding of nuclear structure and nucleosynthesis (for example the r-process, which is responsible for the production of about half of the heavy elements). However, as a result of their short lifetimes, there is a paucity of knowledge about the nature of single-particle states outside exotic doubly magic nuclei. Here we measure the single-particle character of the levels in 133 Sn that lie outside the double shell closure present at the short-lived nucleus 132 Sn. We use an inverse kinematics technique that involves the transfer of a single nucleon to the nucleus. The purity of the measured single-particle states clearly illustrates the magic nature of 132 Sn.