Isotopic analysis of lithium by prompt alpha measurement during deuteron irradiation

Charged particle spectrometry was used to determine the isotopic concentration of lithium in lithium fluoride targets irradiated with a deuteron beam of 4.0 MeV. Alpha particles emitted by the⁶Li(d, α)⁴He and⁷Li(d, α)⁵He reactions were used as a measure of⁶Li and⁷Li, respectively. From the⁶Li/⁷Li α-count ratio the isotopic concentration of⁶Li was determined for isotopic concentrations over the range 7.42 (natural) to about 30 atom%⁶Li, with a relative standard deviation of±4.1%. Alpha particles from the¹⁹F(d, α)¹⁷O reaction could also be measured as an internal standard, extending the measurements from natural to 100 atom%⁶Li and giving a relative standard deviation of ±1.9%. The effect of target thickness on the accuracy of the determinations was investigated.