Simultaneous determination of alpha, beta emitters by liquid scintillation counting In the Indigenously developed Liquid Scintillation Counters

摘要

In connection with the simultaneous determination of alpha, beta emitters by liquid scintillation counting, a systematic study was carried out using toluene based scintillation cocktail obtained from SISCO, Mumbai. A stock solution of extractive scintillator solution containing 20 percent HDEHP was prepared with this cocktail. Scintillator solutions containing lower concentrations of HDEHP were prepared from this stock by dilution and higher concentration by adding required volume of HDEHP. i) Effect of HDEHP: The effect of HDEHP on the extraction of ~(241)Am from nitric acid medium was studied by taking extractive scintillator containing different concentrations of HDEHP. Even with 20 percent HDEHP (an aliquot of 25 lambda of Am in 0.5M HNO_3) only 15 percent of the activity was transferred to the organic phase (Table-1). On the other hand if the acid is evaporated and cocktail added to trie dried radionuclide quantitative assay is possible even in the absence of HDEHP. However, misclassification of alpha events as beta events in LSAI was approx 20 percent without HDEHP which gradually diminished with increasing concentration of HDEHP and came down to 1.5 percent in 20 percent HDEHP.