The Search For The Island Of Stability
September 19, 2012

Finding The Island Of Stability In Super-Heavy Elements

April Flowers for - Your Universe Online

An international group of researchers, led by the University of Granada, has measured the effects of layers on super-heavy elements, providing useful data on the nuclear structure of these as yet undiscovered elements in nature.

The results, reported in Science, might prove useful in locating the "Island of Stability."

The team measured the isotopes of nobelium (No) and lawrencium (Lr) using a particle accelerator at the GSI Helmholtz Centre for Heavy Ion Research.

The Island of Stability is a theory in nuclear physics, which describes a set of as yet undiscovered isotopes of transuranium elements. These elements are theorized to be much more stable than others, with expected half-lives of at least minutes or days, as compared to seconds, with some expecting half-lives of millions of years.

All elements with an atomic number above 82 (lead) are unstable, and the "stability" (half-life of the longest-lived known isotope) of elements generally decreases with rising atomic numbers from the relatively stable uranium (92) upwards to the heaviest known element: 118. It increases very slightly in the range of elements 110 to 113, hypothesized to be at the beginning of the Island of Stability.

Super-heavy elements are those with an atomic number greater than 103. These elements are not "natural," they are created in a nuclear physics lab through the bombardment of elements in a particle accelerator. Super-heavy elements are created in atomic scale quantities, and no method of mass creation has yet been found. There are, however, predictive theories that claim a group of stable super-heavy elements exists in the Island of Stability range.

The stability of super-heavy elements is caused by a layer effect in the atomic nucleus. Protons and neutrons in the nucleus are arranged in layers, with some "magic layers" being very strongly bound, resulting in extremely stable elements. Without this bonding, super-heavy elements would immediately disintegrate due to Coulumb repulsion (the repulsive force between two positive or two negative charges) among protons.

The University of Granada is developing a quantum sensor, a unique device for measuring the greatest mass of nuclei ever measured. This device will be integrated into the GSI's accelerator in Germany, in the SHIPTRAP facilities.

The development of this measuring device (which started in November 2011) has been enabled by a grant of 1.5 million Euros, one of the highest grants ever awarded to the University of Granada for a specific project. The European Research Council awarded this grant to Professor Daniel Rodríguez in 2011 within the topic framework "Fundamental Constituents of Matter"