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We have developed a radiotracer method for diffusion studies in lithium ionic conductors, by using, as the tracer, the short‐lived α‐emitting radioisotope of 8Li from TRIAC (Tokai Radioactive Ion Accelerator Complex). In the method, we measured α‐particles coming out of the sample of interest and have found that the time‐dependent yields of α‐particle from the diffusing 8Li primarily implanted is a good measure of the Li diffusion in the sample. The method has been successfully applied to measure the lithium diffusion coefficients in a typical defect‐mediated lithium ionic conductor of LiGa, well demonstrating that the method is very efficient to measure the diffusion in the micro‐meter regime per second. Further development, as an extension of the present method, was proposed to measure the diffusion on the nanoscale in lithium ionic conductors.

Although the projectile fragment separator (RIPS) at the RIKEN accelerator facility (RARF) provides wide variety of energetic radioactive beams, it is not adequate for low energy beam experiments such as precision spectroscopy of trapped ions. Aiming for an efficient deceleration and cooling of energetic radioactive ions, the development of an rf ion guide system which comprises a large He gas cell and an rf funnel structure in the cell is under progress. A proof of the principle (pop) machine has been successfully tested on-line for collection of 70-MeV/u 8Li ions. A compact gas cell of 70 cm in length and 10 cm in diameter with a He gas pressure of 30 Torr was placed after a variable wedge shaped energy degrader. The ions were stopped in the gas and were transported by a superposition of dc and rf electric field toward a small exit hole. The overall efficiency was 10−4 which can be separated into a gas stopping efficiency of 0.43% and an ion-guide efficiency of 2.4%. The former is limited by the volume ...

A Radioactive beam facility using a thick target, an ISOL and heavy ion linacs will soon come into operation at INS, University of Tokyo. The status of the project together with experimental programs are reported.