Fast determination of 90Sr/90Y activity in milk by Cherenkov counting

Cherenkov counting of the 90Sr/90Y pure beta emitters is an attractive method for 90Sr activity determination, but the color quenching effect may be significant, especially for strongly colored or semi-opaque media. A quench correction method based on the external source of some liquid scintillation systems (named ESAR - external source area ratio) was proposed and checked for aqueous solutions and was proved to be effective also for urine samples. In the present work, the application of the ESAR method for fast determination of 90Sr/90Y activity in milk samples is described.