Reusability of plastic scintillators used in beta emitter activity determination

The use of plastic scintillation in the measurement of beta emitter activity is a suitable alternative to classical detection techniques in spite of the high cost and potential memory effects. Reuse of the plastic scintillator beads after a cleanup procedure would overcome both drawbacks. In the present paper, we tested several cleaning solutions (water, HCl 0.1 M, commercial soap, EDTA 0.01 M pH=3, citric acid 0.1 M pH=3). The recommended procedure consists of the immersion of the beads in three consecutive citric acid baths for 24 h. If this protocol is followed, plastic beads contaminated with 90Sr/90Y, 14C, and 3H recover their initial condition, and can be used in successive determinations.