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We have measured the γ-ray angular distribution of the 12C(α,γ)16O reaction at TRIAC (Tokai Radioactive Ion Accelerator Complex) to accurately determine the E1 and E2 cross sections. In this experiment, we used high efficiency anti-Compton NaI(T1) spectrometers to detect a γ-ray from the reaction with large S/N ratio, intense pulsed α-beams to discriminate true event from background events due to neutrons from 13C(α,n)16O reaction with a time-of-flight (TOF) method. We succeeded in removing a background events due to neutrons and clearly detected γ-ray from the 12C(αγ)16O reaction with high statistics.

The {beta}-decay properties of the neutron-rich isotopes with neutron number N = 126, out of reach by any reaction well established so far, are very interesting from the astrophysical point of view. We will propose {beta}-decay lifetime measurements with a new isotope separation system, which is supposed to separate a single species of the radioactive nuclei among target-like fragments produced via multi-nucleon transfer reactions in binary heavy ion collisions, by using a gas catcher cell combined with laser resonance ionization technique. The present proposal aims to measure {beta}-decay properties of several nuclei around A{approx}200 with N = 126 and nearby nuclei by using a stable {sup 136}Xe beam on a {sup 198}Pt target.

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.

Excitation functions of 8Li(α,n), (d, t) and 12B(α,n) reactions were directly measured in the energy region of astrophysical interest using low‐energy radioactive nuclear beams of 8Li and 12B. Each measured excitation function is strongly affected by one or more resonances through a compound nucleus. The measured excitation functions are presented. Dominant r‐process paths through 8Li at various temperatures are discussed and our future experimental plan is also presented.

A systematic study of astrophysical reaction rates of (α, n) reactions on light neutron‐rich nuclei using low‐energy radioactive nuclear beams is in progress at the tandem facility of Japan Atomic Energy Agency. Exclusive measurements of 8Li(α, n)11B and 12B(α, n)15N reaction cross sections have been performed successfully. Their excitation functions together with the experimental method are presented.

A systematic study of astrophysical reaction rates of (α, n) and (p, n) reactions on light neutron‐rich nuclei by using low‐energy radioactive nuclear beam is in progress at the tandem facility of Japan Atomic Energy Research Institute. Exclusive measurements of 8Li(α, n)11B and 16N(α, n)19F reaction cross sections have been performed successfully. Their excitation functions together with the experimental method are presented.

A low‐energy radioactive‐ion beam separator based on an in‐flight technique was developed at CNS, University of Tokyo and was installed at RIKEN. Using the separator, experiments of the elastic resonance scattering of 11C+p, 12N+p, and 23Mg+p were performed to study resonance levels in 12N, 13O, and 24Al, respectively. New information on spin‐parities and widths for these levels may help understand stellar (p,γ) reaction rates.

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.