Ionization-type smoke detectors

Abstract

A simple model is developed to determine quantitative relations among operating parameters applicable to the design of ionization-type smoke detectors. The model permits the adjustable parameters of operating current, radioisotope source intensity, and cell geometry to be specified for ambient pressure response and optimum sensitivity to smoke particulates. Specific ionization has been measured for two sources (3H and 63Ni) as a function of pressure as required by the model. Experimental agreement with the model presented shows its validity for design evaluation of ionization cells for smoke detection and possibly other special applications with particulates.