Search

A novel vapor delivery testbed, referred to as the Trace Explosives Sensor Testbed, or TESTbed, is demonstrated that is amenable to both high- and low-volatility explosives vapors including nitromethane, nitroglycerine, ethylene glycol dinitrate, triacetone triperoxide, 2,4,6-trinitrotoluene, pentaerythritol tetranitrate, and hexahydro-1,3,5-trinitro-1,3,5-triazine. The TESTbed incorporates a six-port dual-line manifold system allowing for rapid actuation between a dedicated clean air source and a trace explosives vapor source. Explosives and explosives-related vapors can be sourced through a number of means including gas cylinders, permeation tube ovens, dynamic headspace chambers, and a Pneumatically Modulated Liquid Delivery System coupled to a perfluoroalkoxy total-consumption microflow nebulizer. Key features of the TESTbed include continuous and pulseless control of trace vapor concentrations with wide dynamic range of concentration generation, six sampling ports with reproducible vapor profile outputs, limited low-volatility explosives adsorption to the manifold surface, temperature and humidity control of the vapor stream, and a graphical user interface for system operation and testing protocol implementation. [ABSTRACT FROM AUTHOR]

This note describes the design of a simple, wire-array ion gate that is easy to create and machine. The gate consists of two separate wires that can be pulsed differentially to either neutralize ions or deflect the path of an ion beam. Unlike previous designs, the gate described herein consists of only a single piece: an insulator through which two wires are woven to create an interdigitated array. The wires are then terminated at both ends, where electrical connections to external voltage sources can be made. Once constructed, the gate has a 1 mm grid spacing and takes about 3–4 h to complete after the initial support is machined. A gate constructed with this design has been successfully installed in an ion-mobility spectrometer, and its performance compares favorably to that of a previously configured gate system. [ABSTRACT FROM AUTHOR]