| Description |
It is a remarkable feature of nuclear physics that the majority of nuclei are not spherically symmetric but have a deformed shape. Coulomb excitation is a key tool for studying nuclear shapes where colliding nuclei are excited through the exchange of virtual photons. In recent years, the REX-ISOLDE facility at CERN has been leading the study of Coulomb excitation of beams of radioactive nuclei. Data has been obtained which shines a light on the shapes of exotic nuclei and the phenomenon of shape coexistence where nuclei can change shape with the addition of a small amount of excitation energy. Some of the best evidence for octupole (pear) shapes has been found for the very heavy nuclei, 220-Rn and 224-Ra and was reported last year in Nature. The techniques for producing and accelerating radioactive beams will be described along with some of the key results on nuclear shapes that have been obtained in the last few years.
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