helium ionization detector

in gas chromatography
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.
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2191 [Terms] [Paper]