PNNL

Abstract

A 512-channel Faraday-strip array detector has been developed and fitted to a Mattauch-Herzog geometry mass spectrograph for the simultaneous acquisition of multiple mass-to-charge values. Several advantages are realized by using simultaneous detection methods, including higher duty cycles, removal of correlated noise, and multianalyte transient analyses independent of spectral skew. The new 512-channel version offers narrower, more closely spaced pixels, providing improved spectral peak sampling and resolution. In addition, the electronics in the amplification stage of the new detector array incorporate a sample-and-hold feature that enables truly simultaneous interrogation of all 512 channels. While sensitivity and linear dynamic range remain impressive for this Faraday-based detector system, limits of detection and isotope ratio data have suffered slightly from leaky p-n junctions produced during the manufacture of the semiconductor-based amplification and readout stages. This paper describes the new 512-channel detector array, the current dominant noise sources, and the figures of merit for the device as pertaining to inductively coupled plasma ionization.