English: Where do elements come from? How does the strong force bind subatomic particles into nuclei? What can scientists understand from nuclei with unusual proton–neutron ratios? Nuclear physicists at the US Department of Energy’s (DOE’s) Oak Ridge National Laboratory (ORNL) are seeking answers to questions like these.

One element is of particular interest to ORNL. In 2010, ORNL researchers discovered that the nucleus of a tin isotope, tin-132, was doubly “magic.” Isotopes are deemed magic when they have nucleons (positively-charged proton particles or neutrally-charged neutron particles) that complete a shell within the nucleus, making the magic isotopes much more strongly bound than those that are not magic. Isotopes with 2, 8, 20, 28, 50, 82, or 126 neutrons or protons are considered magic. A doubly magic isotope has two of these special numbers—one that describes its number of protons and one that describes its number of neutrons. Tin-132, for example, has 50 protons and 82 neutrons.

Now a team of nuclear physicists at ORNL and collaborators have simulated tin-100, an isotope that researchers have long sought to understand. Tin-100 is not only doubly magic but also possesses the same number of protons and neutrons (50 each). On the chart of nuclides—a table that orders the radioactive behaviors of isotopes—tin-100 exists in a region where, if a proton is added, a proton is ejected from the nucleus in the same way that someone might be eliminated from a game of musical chairs. This nucleus is also located in a region where alpha decay is a competing mechanism to beta decay, making it of astrophysical interest.

+ Read more: www.olcf.ornl.gov/2018/05/01/nuclear-physicists-wield-hpc...