Abstract
Neutron activation analysis of selenium using 75Se has been investigated by means of a coincidence counting of γ-rays in the cascade decay series by a NaI (Tl) detector and a Ge (Li) detector. Using this method, the background around the photopeak of 75Se-265 keV could be reduced to one twentieth, and thus the detection limit of selenium could be improved four times higher than the usual method. For examining the accuracy of this measuring method, selenium contained in Bovine Liver (NBS) was determind and the content of selenium was found to be 1.02μg/g (the certified value is 1.1±0.1μg/g) . Selenium content in Orchard Leaves (NBS) was determind to be 0.081±0.006, ccg/g (the certified value is 0.08±0.01μg/g), though its nondestructive determination was difficult because of its very low content. The results obtained here indicate that the accuracy, the precision and the reproducibility for selenium determintion are thought to be adequate. As an example of a sample containing many interference nuclides, selenium in a soot was determined on the basis of these results.
