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Yokoya, Akinari; Shikazono, Naoya; Fujii, Kentaro; Ushigome, Takeshi*; Suzuki, Masao*; Urushibara, Ayumi; Watanabe, Ritsuko
Proceedings of the 27th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, 8 Pages, 2008/12
It has been indicated that ion particle irradiation to living cells causes a clustered DNA damage site, defined as two or more lesions formed within a few nano meters, in a cell nuclei. The clustered damage is less readily repaired by enzymatic repair system so that it induces biological effects, such as mutation induction. We have studied the mechanism of clustered damage induction by biochemical approaches using closed circular plasmid DNA as a model molecule to be irradiated with He ions from TIARA. We have used base excision repair proteins as enzymatic probes to quantify base lesions. We have also applied a novel method using DNA denaturation to visualize multiple single strand breaks which hardly be detected by conventional method. Our recent results will be reported in this seminar.
Onoda, Shinobu; Hirao, Toshio; Oshima, Takeshi
Proceedings of the 27th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.43 - 46, 2008/12
no abstracts in English
Sato, Shinichiro; Imaizumi, Mitsuru*; Oshima, Takeshi
Proceedings of the 27th Symposium on Materials Science and Engineering, Research Center of Ion Beam Technology Hosei University, p.37 - 42, 2008/12
Degradation modeling of triple junction (3J) solar cell due to proton and electron irradiation is performed with the use of a one dimensional optical device simulator. By fitting external quantum efficiencies of the 3J solar cells degraded by proton or electron irradiation, the short circuit current (Isc) and open circuit voltage (Voc) are simulated. These simulated values are in good accordance with the experimental data. In this modeling, carrier removal rate of base layer (
) and the damage coefficient of minority carrier diffusion length (
) in each sub cell are considered as radiation degradation parameters. NIEL (Non Ionizing Energy Loss) analysis for both radiation degradation parameters is discussed. The radiation degradation of a 3J solar cell can be predicted from correlativity between NIEL and radiation degradation parameters.