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Reactions of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) toward deoxyguanosine monophosphate (dGMP) hydroxyl radical adducts were investigated by pulse radiolysis technique. Edaravone was found to reduce the dGMP hydroxyl radical adducts through electron transfer reactions. The rate constants of the reactions were higher than 4 $\times$ 10$^{8}$ dm$^{3}$ mol$^{-1}$ s$^{-1}$ and similar to those of the reactions of ascorbic acid, which is a representative antioxidant. Yields of single-strand breaks, base lesions, and abasic sites produced in pUC18 plasmid DNA by $\gamma$ ray irradiation in the presence of low concentrations of edaravone were also quantified, and the chemical repair activity of edaravone was estimated by a method recently developed by the authors. By comparing suppression efficiencies to the induction of each DNA lesion, it was found that base lesions and abasic sites were suppressed by the chemical repair activity of edaravone, although the suppression of single-strand breaks was not very effective. This phenomenon is attributed to the chemical repair activity of edaravone toward base lesions and abasic sites. However, the chemical repair activity of edaravone for base lesions was lower than that of ascorbic acid.

Allenes, one of the compounds with cumulative double bonds, are attracting much interests due to the characteristics of their twisted π-conjugated bonds. Several allenes were synthesized to characterize their electronic features by their ground-state absorption, transient absorption and emission spectra to be found that they increase conjugation length in the excited state due to their conformational change. Photophysical process and active species were determined by laser flash photolysis and electron beam pulse radiolysis to find that intramolecular charge transfer of an allene is induced upon electron beam irradiation.

We are commissioning the cathode, Na2KSb at the wavelength of 266, 400 nm with thermo-mechanically modified structure and improved vacuum system (2·10⁻⁰⁸ Pa). We could improve RF reflection waveform and obtain the maximum energy of 22 MeV. We estimate the electrical field of 50 MV at the cathode. So far, we have obtained the quantum efficiencies of 1.1, 0.01% and the maximal charges of 4.6, 1 nC for 266, 400 nm. We are observing and checking carefully individual difference of QE of the cathodes for 266, 400 nm, and we have obtained 22 MeV energy. This new RF photocathode RF gun system has been already used for subpicosecond time-resolved radiation chemistry., Proceedings of the 1st International Particle Accelerator Conference, IPAC2010, Kyoto, Japan