Production of and Physics with High-Intensity Radioactive Nuclear Beam

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The main purpose of the present study is to develop various techniques to realize accelerated radioactive nuclear beams (RNB) that are presently expected worldwide to open new fields of nuclear physics and related sciences. To carry out some pioneering experiments by use of the unstable nuclear beams to show their powerfulness as a new experimental tool is another aim of this work.The following objects were set up in the beginning of the present study and were successfully carried out in collaboration with researchers of several universities and institutions in Europe, Canada and U. S. A. such as CERN (The Switzerland), TRIUMF (Canada) and University of Giessen (Germany). The results have been presented in several international conferences on nuclear physics held in 1992-93 and have also been published in international scientific journals.A. Research and development of highly efficient ion sources for an isotope separator on-line (ISOL)--- ISOL ion sources such as those of surface-ioni … More zation, plasma and ECR types suited for the use of thick targets have been developed in collaboration with INS, CERN and TRIUMF. High ionization efficiencies up to several tens of % were achieved for some elements.B. Detailed design of the high-mass resolving-power ISOL optics--- The ISOL consisting of both magnetic and electrostatic stages have been designed and shown to realize a mass resolving power over 20, 000 by the MonteCarlo simulations. This has been done in collaboration with INS, Tohoku and Giessen Unversites.C. Accelration of radioactive nuclear beams--- A special type of heavy-ion linac, called a split-coaxial RFQ, has been studied in INS and GSI (germany). A prototype accelerator of this type has been constructed at INS, which could successfully accelerate low-speed heavy ions with extremely small charge-to-mass ratios. It has enabled efficient acceleration of radioactive nuclear beams.D. Pioneering experiments on nuclear and nuclear astrophysics with RNB--- The spin polarization of unstable nuclei implanted into solids has successfully been achieved, in collaboration with Kyoto University and CERN, etc., by optical pumping. Nuclear astrophysical experiments to study heavy-element synthesis in the universe were also carried out in RIKEN, INS and are in progress at GANIL (France). Less