Researchers at Argonne are probing the very edges of nuclear stability - and beyond - with the aid of a 12-ton gamma-ray "microscope" called Gammasphere. A $20 million national traveling physics instrument, Gammasphere was built to study the complex structure and behavior of nuclei by fusing lighter nuclei into heavier ones and observing gamma rays - a form of extremely high-energy light - emitted when the new nuclei's component protons and neutrons settle into stable configurations. Argonne physicist Kim Lister is at the center of the machine. Argonne National Laboratory photo.

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