Determination of 210Pb in marine sediment core- A comparison between alpha and gamma techniques

The most commonly used techniques of alpha and gamma spectrometry were performed to measure 210Pb activity in marine sediment core as a comparison. Alpha analytical technique measured the activity of 210Pb from its in-grow grand-daughter 210Po after a chemical separation, assuming radioactive equilibrium between the two radionuclides. Meanwhile, gamma analysis technique allows direct measurement, non-destructive and no preliminary chemical separation. Through the comparison, it is found that both alpha and gamma analysis techniques were slightly difference. Overall, the results from alpha analytical technique were basically higher than those from the gamma analytical techniques. Some logical argument had been discussed to explain this situation. In routine analysis, the analytical technique used should be chosen carefully based on advantages and disadvantages of the each technique and analysis requirements. Therefore, it is recommended to determine exactly the needs and purpose of analysis and to know the sample history before decide the appropriate analytical technique. (author)