New gamma-ray detector to uncover structure of the atomic nucleus

London, Oct 31 : UK physicists are constructing a new gamma-ray detector that will help to uncover the structure of the atomic nucleus, as well as in the advancement of medical gamma-ray technology, used in hospital scans.

Named as the Advanced Gamma Tracking Array (AGATA), it will be a thousand times more sensitive than previous detectors.

Atomic nuclei make up most of the visible matter in the Universe, including ourselves. So, unlocking their structures is of great significance in not only understanding how the forces of nature work but also how the elements were created.

By probing the structure of rare exotic atomic nuclei, with significant or extreme ratios of protons to neutrons, we may reveal why certain proton-neutron combinations are more stable than others, or have particular shapes.

It may also shed light on how the elements are built up in stars, thought to happen via processes involving nuclei that are unusually rich in neutrons or protons.

Another goal is to make massive nuclei with as many protons as possible in pursuit of discovering new super-heavy elements.

Like previous gamma-ray detectors, AGATA collects the gamma rays emitted when the nuclei decay, or when they are excited into a higher energy state by a laser or a collision with another particle.

However, it differs from previous detectors in that the germanium detectors fill up the entire sphere, which dramatically improves the sensitivity.

The paths of the gamma rays, as they bounce around inside the detector, can be reconstructed using state-of-the-art computer methods. This enables the researchers to record both the position and energies of all the gamma rays reaching the detector.

The characteristic spectrum of gamma-ray energies reveals much about the energy levels in the nuclei, the arrangement of protons and neutrons, and the overall shape of the nucleus.

The social and economic benefits of AGATA include improved gamma-ray technology for PET and SPECT scanners - medical imaging and diagnosis machines which produce three-dimensional images of people's bodies to provide information about localized function in internal organs and detect disease and tumors.

Work is already in hand to develop portable radiation monitors based on AGATA technology, which could be used by the security services to detect dirty bombs, and also to monitor radioactive waste.

According to Professor Keith Mason, Chief Executive of STFC, "This project is an exciting new step on our journey to uncover the structure of matter. It's also a prime example of how fundamental research can have great economic and social impact on our everyday lives."

ANI