A Broad-Range Ionization Detector

Abstract

In the course of designing an electron attachment detector, a study of design parameters led to some rather interesting results. The effect of interelectrode distance was of particular interest. This variable has a pronounced effect on attachment behavior at spacings less than 8 mm, the extent of the attachment effect decreasing abruptly as spacing is reduced below this value. At very narrow spacings virtually no attachment occurs, resulting in high sensitivity to permanent gases. Thus, a detector with adjustable electrode spacing, as described, can be used for both fixed gases and electronegative materials. Applications are presented which illustrate the detector’s versatility and sensitivity in various operating modes.