A simple template-based transfer method to fabricate Bradbury–Nielsen gates with uniform tension for ion mobility spectrometry

Abstract

A Bradbury-Nielsen gate (BNG) consists of two interleaved and electrically isolated sets of wires. It is usually used to gate or modulate ion beams. Uniformly tense wires can remain parallel, equidistant, and coplanar over a wide working temperature range, which is critical to reliable BNG performance. Hence, this study analyzes the non-uniform tension of wires wound using traditional sequential winding methods in which the elastic modulus of the metal wire is much larger than that of the insulation substrate. To address this problem, a simple and reliable template-based transfer method is developed. First, a template with large elastic modulus is used to fabricate a wire mesh with uniform tension. The mesh is then transferred to the substrate. Theoretically, this method reduces the non-uniformity of the tension in wires to less than 2%; therefore, it is used to construct a BNG with stainless steel wire, a stainless steel template, and a printed circuit board substrate. The BNG was installed in our homebuilt ion mobility spectrometer. To confirm that the performance of the BNG meets the requirements of portable ion mobility spectrometry, signal intensity and resolution (approximately 30) were experimentally determined.

Toward Compact High-Performance Ion Mobility Spectrometers: Ion Gating in Ion Mobility Spectrometry

“…The width is limited by the minimal structure size supported by Ätztec GmbH. However, compared to similar approaches reported in the literature, , utilizing PCB mounted Bradbury-Nielsen shutters, the spacing could be reduced from 1 mm down to 720 μm. Etching the wires from one foil allows the electrodes to be placed all at once on the pads of a PCB (Figure , right) and soldered in a reflow process.…”

Field-Switching Repeller Flowing Atmospheric-Pressure Afterglow Drift Tube Ion Mobility Spectrometry

“…However, BNGs (and TPG to a higher degree in some cases) in DTIMS suffer several disadvantages, including intrinsic low duty cycle (1%), 1,16,17 physical ions loss on BNG surface wires, 1 gate depletion effect (GDE), 18,19 and difficulties pertinent to construction, such as the small inner distance among wires (<1 mm), especially if a high working temperature across the IMS cell is desired. 20,21 One of the main issues associated with the BNG is the gate depletion effect (GDE) during injection into the drift region. When the closing potential is applied to the BNG wires at the end of the gating pulse, the electric field induced will "pull back" the ions that have not traveled a sufficient distance from the BNG plane.…”

“…Therefore, electrical ion gates are commonly deployed in IMS to generate discrete ions packet for separation. However, BNGs (and TPG to a higher degree in some cases) in DTIMS suffer several disadvantages, including intrinsic low duty cycle (1%), ,, physical ions loss on BNG surface wires, gate depletion effect (GDE), , and difficulties pertinent to construction, such as the small inner distance among wires (<1 mm), especially if a high working temperature across the IMS cell is desired. , …”