Ionization chamber for smoke detector and the like

摘要

An ionization smoke detector is disclosed in which an electric field is established in an ionization chamber which includes an outer cup-shaped electrode defining the chamber and having side wall apertures for permitting airflow therethrough and a circular inner electrode within the chamber. A radiation source is arranged to produce bipolar and unipolar regions in the chamber. A cylindrical control screen coaxial with the outer electrode and spaced therefrom is electrically connected to and supported by the inner electrode in the chamber.