Determination of low-energy β-emitter radionuclides deposited on surfaces by attapulgite treatment

Abstract

A method for the determination of surface contamination of various materials by ³H and ⁹⁹Tc is reported. Both ³H and ⁹⁹Tc^m are widely used in chemical and clinical applications. The isotopes ⁹⁹Tc, the decay product of ⁹⁹Tc^m, and ³H are soft β-emitter radionuclides and the use of unsealed sources can frequently produce contamination and excessive internal dosing for workers. The removal of radionuclides from surfaces was effected with attapulgite, a clay with a high absorption capacity for many organic and inorganic substances. The determination was carried out by extracting the absorbed radionuclide from the clay and then measuring it in a β-scintillation counter. The determination limits of the method, 20 Bq cm^–2 for ³H and 100 Bq cm^–2 for ⁹⁹Tc, are below the “derived working limits” for these radionuclides.