Analyses of the EPR responses of sucrose and L-alpha-alanine radicals induced by C, Ne, and Ar ion irradiations.

Using electron paramagnetic resonance (EPR), we investigated the signal responses of sucrose and L-alpha-alanine radicals produced by heavy-ion irradiation with various linear energy transfers (LETs) and absorbed dose. The spin yields for the two compounds showed a linear relation with the absorbed dose, as well as a logarithmic correlation with the LET. A quantitative EPR analysis showed that sucrose was more sensitive to the particle species than that of alanine. Hence, the present EPR results imply that sucrose can be useful as a radiation indicator. Further analysis was carried out for the radical-production cross section, which showed that stable radicals of the two compounds were produced through collisions of several particles with a single molecule.