► The quest for superheavies
Nuclei appear to be more robust when they have 2, 8, 20, 28, 50, 82, or 126 protons or neutrons. These are the nuclear magic numbers. Based on these, the existence of very heavy nuclei composed of 114 to 126 protons and 184 neutrons can be predicted. These chemical elements, 15 times heavier than lead, are said to be superheavy. They are now actively sought after, and the high intensity of the SPIRAL2 beams, as well as its new installations, will be major assets in this race.
| ► The revolution of magic numbers
The structure of exotic nuclei seems to ignore these magic numbers.
Scientists sometimes see them disappear, whereas others appear.
With SPIRAL2, the evolution of magic numbers will be monitored up to the boundaries of the existence of nuclei, in an attempt to understand this still unsolved phenomenon.
| ► The nuclear cohesion forces
The properties of exotic nuclei, their cohesion, size, excited levels, shape …, are determined by a subtle balance between the forces they experience. As a result of a strong modeling effort, the results from SPIRAL2 will help in the evaluation of these forces, in particular those which act in neutron-rich nuclei. | ► The origin of heavy elements in the Universe
Exotic nuclei are produced during nuclear reactions in the Universe.
To understand where these elements come from, and their abundance on Earth, the properties of exotic nuclei, and the nuclear reactions which created them, must be understood.
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► The nuclear matter of neutron stars
The protons and neutrons in a nucleus form a liquid with an "extraordinary" density. This neutron-rich liquid consitutes the heart of supernovae and neutron stars.
SPIRAL2 will create this kind of matter on Earth, in reactions with highly neutron-rich projectiles.
| ►Fundamental interactions
Exotic nuclei transmute, through beta radioactivity, into more stable species. They may thus be used to study the fundamental properties of the weak nuclear force, which is at the origin of this phenomenon. | ► A high-performance, fast neutron source
SPIRAL2 will be the most powerful, fast neutron source in the world, and is expected to maintain this position for the next ten years.
With it, it will be possible to obtain data on neutrons, thereby contributing towards even safer, and more environmentally friendly nuclear energy.
| ► A multidisciplinary platform
This new, high-performance facility is open to multidisciplinary research, and will bring together the scientific communities who work in atomic physics, solid physics and radiobiology, with irradiated matter being the primary focus of attention. |
