This method specifies the minimum requirements and laboratory methods for measuring 238Pu and 239,240Pu in sediment samples via alpha-counting.
Before digestion, the sample should be ashed at 480 ℃ for 48 h in order to remove the organic matter. This method will meet difficulties when the counting statistics are low or when the alpha spectrum is disturbed by natural radioactivities in the sample or background (Hakanen et al., 1984). It is thus necessary to collect the enough sample volume (about 100 g) due to low 238Pu activity. Interference is especially due to 228Th, indicated by the presence of 224Ra in the alpha spectrum. Meanwhile, this method cannot separate 239Pu and 240Pu because of their similar energy.
|View Recipe (pdf)|