RadioaktiveIonenBeams

RadioaktiveIonenBeams, also known as radioactive ion beams (RIBs), are beams composed of unstable atomic nuclei produced for experimental investigations in nuclear physics, nuclear astrophysics, and related fields. They enable studies of nuclei far from stability, including their structures, decay modes, and reaction properties, which are otherwise difficult to access with stable beams.

RIBs are produced mainly by two methods. The Isotope Separation On-Line (ISOL) technique begins with a thick target where a reaction such as fission or spallation creates a range of radioactive isotopes. The isotopes are chemically extracted, ionized, mass-separated, and then accelerated to low or intermediate energies. Some isotopes are later reaccelerated to higher energies for experiments. The ISOL method provides high beam purity and relatively large intensities for many elements but is limited by the chemical release and extraction times, which depend on the isotopes’ chemistry and half-lives. The in-flight technique uses projectile fragmentation or fission of a high-energy primary beam to produce short-lived fragments directly in-flight. These fragments are momentum-selected and delivered at high energies, offering access to very short-lived species, though with typically lower purity and broader energy spreads than ISOL beams.

Key facilities worldwide include ISOLDE at CERN, FRIB in the United States, GANIL and FAIR/GSI in Europe, and RIKEN in Japan. RIBs support a range of experiments such as spectroscopy of exotic nuclei, measurements of decay properties, mass determinations, reaction-rate studies relevant to stellar nucleosynthesis, and tests of fundamental symmetries.

Challenges for RIB research include limited intensities due to short lifetimes, complex separation and purification requirements, and the need for sophisticated detection systems and remote handling. Ongoing developments aim to extend reach, improve beam quality, and expand applications in physics and medicine.