Determination of lithium and its isotopic composition by activation analysis and measurement of8Li and17N

The non-destructive determination of lithium was performed by using a Cerenkov counter for the detection of the 13 MeV (max) β-particles from the 0.84 sec⁸Li produced by the reaction⁷Li(n,γ)⁸Li. Under optimal conditions for a favorable signal-to-noise ratio, a count rate of about 35 cps/μg lithium at the beginning of the measurement was obtained, with a background of 4.5 cps and a working range of 3–400 μg lithium. The interference of other elements was studied. Several lithium-containing minerals and a sample of Dead Sea water were analyzed. The isotopic composition of lithium in aqueous solutions was determined by the simultaneous measurement of the neutrons produced by the reactions⁶Li(n,α)t and¹⁸O(t,α)¹⁷N, and the β-particles emitted by⁸Li.