50-Channel charge integrating faraday detector for characterization of ambient ions

Abstract

Herein we present a novel 50 channel, charge integrating, Faraday plate detector system for the detection, characterization and imaging of charged particles emitted from an ambient ionization source. The detector is capable of spatial positioning of ion beams with sub nA current intensity, high linearity, large dynamic range and dark current noise <10 pA. Each channel is connected to its own calibrated amplifier for true simultaneous integration. To demonstrate the detector capability, 2-dimensional ion images are presented for ions emitted from a desorption atmospheric pressure chemical ionisation source with peak ion current of ∼30pA. The novel detection system facilitates the characterization and optimization of ambient ionisation sources in terms of electrical and geometric conditions for improved ion generation and coupling with a mass spectrometer.