A system for accurate and fast measurement of the gas phase H/D ratio in electrolytic H/D separation factor experiments

Accurate and fast measurements of electrolytic hydrogen-deuterium separation factors are required to study short-term time effects and the effects of other variables, for example overpotential, before the cathode has suffered irreversible changes such as hydrogen embrittlement. A system for fast measurement of the hydrogen-deuterium ratio of the liberated hydrogen isotopes in argon as the sweep gas has been developed and is described in detail. Unique features include a modified Cartesian manostat and an automatic Toepler pump in the gas collection system, and an automatic mass spectrometer inlet system whose cycle time is about 4 min. Calibration procedures are outlined. The accuracy and reproducibility in the H/D ratio are ±1% and ±0.5% respectively, for the range 0.75 to 5.0 mol. % deuterium in mixtures containing 0 to 80 vol.% argon.