Electron capture detector

ECD with a non-radioactive electron source for generation of ions in a reaction chamber. The reaction chamber consists of two partial chambers, of which one is evacuated and contains the electron source, and the other contains connections for the feeding in of analysis gas as well as a collector electrode for detecting ions. The partition between the two partial chambers is permeable for electrons from the source but impermeable for gas molecules. The electron source may be a thermoemitter or a photocathode, which is irradiated from the outside through a window. In this way, contact between the analysis substance and the electron source is prevented, which increases measurement stability.