15 August 2012
One of the most sought-after goals in nuclear physics is an understanding of the structure of superheavy elements in the so-called “island of stability.” These nuclei contain a large number of protons, and would ordinarily be ripped apart by the strong Coulomb repulsion between them. However, quantum mechanical shell-effects act to stabilize the nuclei, meaning that they can then live long enough to be observed in the laboratory.
In order to understand these “shell effects,” detailed experimental studies are needed. Such studies are unfortunately precluded by the fact that superheavy elements can only be produced in small numbers (sometimes only a few atoms per month). It is, however, possible to study lighter nuclei in more detail. These studies can be used to gain indirect information on the island of stability.
Now, experimental advances at the Accelerator Laboratory of the University of Jyväskylä (JYFL-ACCLAB), Finland, have meant that it has been possible to study the nucleus 256Rf in detail for the first time. The facilities at JYFL-ACCLAB are currently the only ones worldwide which permit such studies to be carried out. The 256Rf nucleus has 104 protons, which corresponds to the accepted gateway to the superheavy elements. The 256Rf nucleus is the heaviest which has so far been studied in this manner.