Present status and future subjects of the analytical studies related with application of charged particles and RI to materials science and biotechnology

The position in the research field of radiation application of Theoretical Analysis Group for Radiation Application' which will be set up within fiscal 2003, and the relation between the research that this analytical group will advance in future and the analytical research made so far at Takasaki Radiation Chemistry Establishment (JAERI, Takasaki) are summarized. Since the JAERI Takasaki was founded as the center of the research and development on radiation chemistry, a lot of outcomes have been obtained in the research and development of radiation application using large-sized sup 6 sup 0 Co gamma ray irradiation facilities and high power electron accelerators, etc. After the ion irradiation research facility (TIARA) started operation, many outstanding outcomes have been obtained in the research of up-to-date science and technologies in the fields of material science and bio-technology, etc., making use of ions in addition to gamma rays and electron beams. Although these results of the research are mainly produced experimentally, theoretical analyses also are thought to be important because these results will be applied and expanded in future. We aim to set up 'Theoretical Analysis Group for Radiation Application' in fiscal 2003, and we aim at performing theoretical and engineering analyses about phenomena and things such as radiation chemical reactions, irradiation/implantation effects to semiconductors, model for plant function, etc. The irradiation effects of charged particles to materials are divided into the primary effects like generation of radicals and lattice defects, etc., which occurs immediately after charged particles impinge on materials, and the secondary effects like chemical changes and physical changes caused in materials as a result of the primary effects. The subjects of our analytical research are the analyses of the secondary effects and the systems which utilize the chemical and the physical changes to the radiation application. It is making analysis keeping close cooperation with the experiment. In order to utilize and develop a lot of practical outcomes which have been obtained experimentally up to now, first, the theoretical analysis group for radiation application extracts only the core element from the analysis of reactive process of charged particles in the materials and from the irradiation effect, and then constructs the simplified model. Second, the validity of the constructed model is verified by advancing the theoretical analysis based on the model, and the calculated result is fed back to the experiment, and then the verification is carried out. The data collection and the analysis in each analytical item will be conducted in fiscal 2003-4, and modeling will be carried out for possible ones. For the item in which modeling has been already finished, the theoretical analysis like the material structure and physical properties, etc. will be implemented. On the other hand, for the items like the material transfer in higher plants and the biological effects, etc. in which the analysis of experimental results leading to the basis for the theoretical treatment has just started modeling will be carried out in parallel with the experiment, and the simplified model will be constructed. In fiscal 2005-6, the analysis based on the simplified model will be advanced, and the elaboration of modeling will be carried out based on the result of the verification experiment. Finally, the general-purpose theorization will be conducted by generalizing and universalizing the obtained model concerning the specific system. The obtained outcomes will by applied to other systems, and, will consequently, contribute to the promotion of new technological development.