Electron spin resonance signal of human nails: increase after irradiation

We report the phenomenon whereby the electron spin resonance signal of human nails intensify after irradiation. Forty nail samples from three donors were divided into three groups (X-ray irradiated, γ-ray irradiated, and control). The extent of signal intensified after irradiation was proportional to the given dose under 11% humidity at 20 °C. This result seemed to contradict previous studies, reporting signal fading. Based on literature and our experimental results, we constructed a model taking both the decay and increase into consideration. Our investigation revealed that rapid deterioration in the signal intensity obscured the increase at humidity levels exceeding 40%.

The alpha effectiveness of the dating ESR signal in barite: possible dependence with age

The alpha effectiveness value (k-value) for the ESR (Electron Spin Resonance) signal due to SO3- in barite was revised by comparing the dose responses of the signal intensities to gamma rays and to 4 MeV He+ ion doses in natural sea-floor hydrothermal barite samples actually used for dating. Of the values obtained for a synthetic, a natural old, and a natural young samples, the one for the natural young sample is tentatively adopted, which is 0.053 ± 0.006, although further works are still necessary to establish this value.