helium ionization detector

in gas chromatography
https://doi.org/10.1351/goldbook.H02767
A weak beta source and a high potential raise the helium atom of the @C00863@ to a @M03872@ state. All other substances having an @I03208@ lower than $$18\ \text{eV}$$ are ionized, and the current that results is used to measure the components. The detector is usually employed to measure inorganic compounds at concentrations between $$0.1$$ and $$10\ \text{ppmv}$$. It has a @L03558@ of about $$10^{2}$$ but is somewhat @U06569@ and requires great care to ensure the helium purity and to eliminate all leaks in the system.
Source:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2191 [Terms] [Paper]