NEUTRON-ACTIVATION ANALYSIS OF LI-6 ISOTOPIC ABUNDANCE USING A LOW-BACKGROUND LIQUID SCINTILLATION-COUNTER

A neutron activation method based on the measurement of tritium radioa ctivity produced by Li-6(n,alpha)H-3 reaction was applied to determine the isotopic abundance of Li-6 in aqueous solution with known lithium concentration. Tritium radioactivity was measured with a low backgrou nd liquid scintillation counter over a period of 2000 min. The present method demonstrated a good linearity between the isotopic abundance o f Li-6 and tritium radioactivity produced per unit amount of lithium i n a wide range of lithium concentration. A comparison of the present d ata with those from mass spectrometry showed agreement, though our met hod was 10 times less sensitive, than mass spectrometry. The present n ew approach should thus prove quite useful for determining the isotopi c abundance of Li-6.