Trace Gas Field Instrumentation Van and Explosive Detection Research.

摘要

The Plasma Chromatograph (PC) is an analytical instrument that is nearly ideally suited for explosives vapor detection. It is sensitive, rugged, has a moderate selectivity, operates at atmospheric pressure, and, in the negative mode, responds to relatively few substances except the nitrated compounds used as the basis for explosives. The scope of the present contract was to quantify the sensitivity of the Plasma Chromatograph to explosive materials and to investigate and put into practice ways of improving its sensitivity and selectivity. A thorough understanding of the processes of production of identifiable ions and the way in which the instrument responds to them is necessary before it can be developed into a practical explosives detector. The sensitivity of the Plasma Chromatograph was analyzed and quantified in terms of the ionization efficiency for a given material and the detectability of an ion once produced. Ionization efficiency depends upon the type and relative speeds of reactions occurring in the vicinity of the radioactive source region of the Plasma Chromatograph, whereas detectability is a function of transmission losses and instrument noise.