Spin-Aligned Radioactive Isotope Beams via Two-Step Fragmentation Reaction

Recently the “dispersion-matching two-step projectile-fragmentation (PF) method” has been developed as a new spin manipulation technique for a quantum system called a radioactive isotope (RI) beam [1]. This method obtains an RI beam with a high production yield while producing universally high spin alignment for a large variety of RIs. A proof-of-principle experiment was performed at the RIKEN RIBF facility [2]. By applying this method, it is expected that the measurement of the nuclear moment of an unstable nucleus, which was previously impossible, can be accomplished. In this article, after discussing the conventional mechanism for producing a spin orientation, the principle of the new method, demonstration experiments, evaluations based on the results of these experiments, and future prospects are described.