Effects of low-dose X-ray irradiation of eggshells on radical production.

We investigated effects of low-dose X-ray irradiation on eggshells radical production. Eggshells irradiated by low-dose X-ray produced stable radicals. The stable radicals at the central region of the spectrum are the carbonates and CO2(•-) signals. The electron spin resonance (ESR) signals increase with increasing absorbed dose. The estimated radical concentration (spin number) was approximately 3.6 × 10(12) (spins/g) at 10-Gy dose using various known concentrations of TEMPOL (4-hydroxy-2, 2, 6, 6-tretramethylpiperidin-1-oxyl) aqueous solutions. The stable radicals in irradiated eggshells were recognized at the low-level dose (0.10 Gy). In addition, no significant dose rate (0.5-1.5 Gy/min) dependence was found for the radical production.