Lifetime of paramagnetic E1 centers in quartz rocks

Conclusions In quartz rocks E₁ centers are formed in both paramagnetic and nonparamagnetic states under the effect of the natural background of ionizing radiation.Nonparamagnetic E₁ centers go over into the paramagnetic state under the effect of heat on quartz (thermal activation of E₁ centers).The rate of thermal activation depends on the absolute temperature of the specimen.Two subtypes of E₁ centers differing as to the rate of thermal activation were detected.By quasilinear extrapolation in the coordinates (C_E–C₀)/(C_M–C₀)-t^1/2 it was found that thermal activation of E₁ centers of the first type, determined from the initial segments of the process, whould be completed at the usual temperature of 293°K (20°C) in 0.8·10⁸ yr.Annealing of E₁ centers of the first subtype in natural occurrence (at 293°K) is completed in 6.4·10⁸ yr. The time for the completion of the thermal activation and annealing of E₁ centers of the second subtype is roughly an order of magnitude longer than in the case of the first subtype.As a result of a long experiment (3 yr) it was established that at 423°K (150°C) the method of quasilinear extrapolation inables the thermal activation time to be estimated more accurately than does the barrier-activation theory usually employed.Translated from Atomnaya Énergiya, Vol. 49, No. 1, pp. 31–33, July, 1980.