Title

An experiment to distinguish between homogeneous and heterogeneous response mechanisms in a parallel-plate electron-capture detector

Document Type

Article

Publication Date

1987

Publication Title

Journal of Chromatography A

Volume

406

Issue

C

First Page

81

Last Page

93

Abstract

A 63Ni parallel-plate electron-capture detector was run under two disparate conditions: one as closely as possible resembling a homogeneous plasma ("stirred reactor"), the other resembling a typically heterogeneous plasma ("space charge") system. The latter produced a response almost two orders of magnitude larger than the former, both under d.c. and pulse regimes, and its linear range was more than one decade longer. Enhancing homogeneity by using two radioactive foils, i.e. by making both the cathode and the anode radioactive, diminished the response of the former but heightened the response of the latter system. This is consistent with the idea that (at least) two mechanisms are operating. It is apparent that, under conditions prevailing in most conventional parallel-plate electron-capture detectors, response arises predominantly from space charge mechanisms. © 1987.