Trapped and stored: atomic nuclei reach for the stars

Tuesday 7 September 2010

Surrey-led experiment, studying nuclear physics at GSI, a German accelerator laboratory, has discovered new nuclear "isomers", which are long-lived excited states of nuclei. The results have been accepted for publication in Physical Review Letters.
 
The title of the publication is "Discovery of highly excited long-lived isomers in neutron-rich hafnium and tantalum isotopes through direct mass measurements".

Exotic atomic nuclei, trapped in previously unknown excited states, have been discovered using an ion-storage ring. This is the first such application of a storage ring and represents the unique capabilities of the heavy-ion accelerator laboratory at GSI in Darmstadt, Germany. First, gold ions were accelerated to three-quarters the speed of light and fired at a beryllium target. Then individual fragments from the collisions were stored and monitored for periods of up to 30 minutes to give precise identifications of each nuclear species, and to measure their stability. The kind of trapped nuclear state found in this way only exists naturally in exploding stars, and laboratory observations may be useful in pinning down the explosion conditions. It is also hoped that the trapped states will be useful for the investigation unknown processes at the borderland between atomic and nuclear physics, perhaps leading to novel energy-storage devices. For the time being, however, the newly developed experimental techniques will be focussed on the exploration of the limits of nuclear binding, thus providing key information about the forces of nature that hold together the matter that we are made of.

The Surrey researchers include PhD students, Matthew Reed, Ian Cullen, Ryan Kempley and Tom Swan, a post-doctoral fellow, Ajay Deo, and Professor Phil Walker, who is the spokesman for the research.