αアラニンおよびＮアセチルアラニンの重粒子線照射で生成するラジカルの検出

The characteristics of irradiation with C290MeV/u ion beams were investigated using X-band ESR spectroscopy for a polycrystalline powder of L-alpha-alanine at from 77K to 310K. The formed main radicals at 190K~310K were the deamino radical and the decarboxyl radical. Because of the first-derivative ESR, decarboxyl radical showed an expanded spectral width and a lower peak height because of its amino hydrogen and nitrogen than that of the same amount of deamino radical. The ESR of irradiated L-alpha-alanine predominantly indicates the spectrum of the deamino radical. On the irradiated, L-alpha-alanine at from 77K to 310K ESR showed 1:4:6:4:1 lines at 220K and at room temperature, which indicate that the methyl group of the radical was rotating. On the other hand, at 77K ESR the spectrum showed nearly 1:5:5:5:1 lines, like the teeth of a saw, on samples irradiated at 270~ 350K (range IV), and 1:4:6:4:1 lines for those irradiated at 180-260K (range II and III), respectively. It is considered that the radical conformation of the deamino radical is planar (most stable conformation) on an irradiated sample in range IV, and a pyramidal structure on the irradiated sample in ranges II and III