Daresbury technology helps beam physicists into unexplored territory at CERN

13 March 2020

Technology developed at STFC’s Daresbury Laboratory has played an exciting role in an experiment at CERN to shed light on how heavy elements, such as gold, are formed in the universe.

The ISOLDE Solenoidal Spectrometer (ISS).
(Credit: Ben Kay, Argonne National Laboratory)

Scientists believe that many heavy elements form in cosmic environments rich in neutrons – think exploding stars and stellar collisions. In these extreme settings, atomic nuclei can rapidly capture neutrons and become heavier, creating new elements.

These heavy elements lie at the far reaches of the nuclear chart, which arranges all known nuclei according to their number of protons and neutrons. Here lie unexplored nuclei that are crucial to understanding this rapid neutron-capture process.

Now, at CERN’s ISOLDE nuclear physics facility, researchers have stepped into this nearly uncharted region of the chart with a first study of the structure of a specific isotope of mercury, a very close neighbour of these heavy ‘neutron grabbing’ nuclei. This research, which will help solve unanswered questions about how heavy elements are formed in the universe, has been published in Physical Review Letters.

This research also marks the first published results of an experiment performed using the ISOLDE Solenoid Spectrometer (ISS) instrument, a newly developed, cutting edge magnetic spectrometer, funded by STFC and constructed through an international collaboration between STFC’s Daresbury Laboratory, the universities of Liverpool and Manchester, Leuven University (Belgium) and Argonne National Laboratory (USA).

As part of this experiment, ions of a selected radioactive isotope of mercury were accelerated to energies of approximately 1.52 billion electron volts, which then bombarded the heavy hydrogen target positioned at the centre of the ISS.  During this process, the ISS cleverly revealed the mercury isotope capturing a neutron in real-time. The researchers then used the results from this experiment to test and challenge the current theories.

STFC Daresbury Laboratory’s Ian Lazarus, Technical Coordinator for the ISOLDE-ISS project, said: “Nuclear physicists aim to create and study the very rarest and heaviest elements predicted to exist, so it’s really exciting to see the magnet, which we recycled from an old MRI scanner, playing a crucial role at the heart of the cutting-edge ISS spectrometer to deliver this ground breaking science.”

Read about this research in more detail at the CERN website.

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