RI beam facility project at RIKEN and physics programs

Abstract

In the Radioactive-Isotope Beam Factory (RIBF) project in RIKEN, intense primary beams can be provided at the energies E = 350−400MeV over the whole range of atomic number in the cascade-cyclotron acceleration scheme, for which three cyclotrons, fRC, IRC, and SRC, have been newly constructed. The project proceeds through two phases. In the phase-I program, the superconducting in-flight radioactive-isotope beam separator BigRIPS and the following ZeroDegree spectrometer have been installed as well as the three cyclotrons. In the commissioning, after the successful extraction of a 238U beam from SRC at E = 345 A MeV in the cascade-acceleration scheme, radioactive-isotope beams were produced and isotope-separated with BigRIPS as designed. The RIBF project is fully capitalized in the phase-II program, in which the construction of several experimental key devices has been proposed. The upgrade of the former fragment separator RIPS is also included there. It allow for a scheme to use intense primary beams at the intermediate energy E = 115 A MeV with RIPS. Remarkably, the produced radioactive-isotope beams at this energy can be spin-polarized taking the advantage of the fragmentation-induced spin orientation phenomena.