A precision isotope ratio mass spectrometer for the analysis of 6Li/ 7Li

Abstract

An isotope ratio mass spectrometer is described which is capable of measuring 6Li/ 7Li abundance ratios with a reproducible precision of ∼±4.0 · 10 −4 at the 95% confidence level. The instrument includes a Knudsen cell-electron impact ionization source, a 90° magnetic sector and a double collector system. The ion currents are integrated digitally following v-to- f conversion. The precision, accuracy, reproducibility, and sensitivity of the instrument are described.