Resin and bark of pine (Pinus silvestris) as new objects for retrospective dosimetry by the EPR method

The EPR spectra of irradiated and non-irradiated bark and resin of pine were investigated in order to determine the possibility of using these objects for retrospective dosimetry. It was shown that yield of gamma-radiation induced free radicals in bark is to 2–3 times higher than for resin. The stability of these free radicals in conditions of normal and exceptionally high humidity in resin is higher than for bark. Dose dependencies of radiation-induced free radicals in bark and resin were investigated up to 1 kGy. The minimum dose which we could determine from the EPR signal for resin was 10 Gy. Thus pine resin is suitable for retrospective dosimetry for a relatively long period after irradiation, while bark is suitable object for a shorter period.