Design and construction of a mechanically simple, interdigitated-wire ion gate

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.