Over the past century, mass spectrometry (MS) has become one of the most utilized analytical tools. This technique, applied to everything from atomic analyses to protein characterization, has undergone numerous advancements; several of which have been honored by Nobel Prizes. However, these advances have focused mainly on the ionization and mass separation portions of MS instruments. While innovations in these areas are important, the components of ion detection have not received the same attention.

In contrast to the simultaneous detection that is now commonplace in optical spectroscopy due to the development of multichannel photon detectors such as charge-transfer devices, the majority of MS instruments remain scan- or pulse-based because of the lack of a suitable multichannel ion array detector. As a result, the duty cycle in such instruments is greatly diminished because only a single mass-to-charge (m/z) value is acquired at a time; meanwhile all other ions are lost. Furthermore, when transient sample introduction methods such as chromatographic separations are used prior to the MS, the relative signal between several analytes can appear amplitude-skewed due to the need to scan during the time-changing concentration profile. Finally, the precision of ratio measurements is greatly deteriorated because correlated noise remains problematic when each analyte is determined at a different time. Importantly, these problems can all be overcome by employing an array of detectors to acquire many m/z values simultaneously.

Such an array detector, termed the focal plane camera (FPC), has been developed and coupled to a simultaneously dispersing and focusing Mattauch-Herzog mass spectrograph (MHMS). These detectors, employing individual micro-Faraday-strip detecting elements and amplifying units in a 1:1 ratio, are shown to be as sensitive as the single-channel counterparts while overcoming the problems described above for scan-based instruments. Three generations of the FPC device have been constructed and characterized using both an inductively coupled plasma (ICP) ionization source and a novel flowing atmospheric-pressure afterglow ionization source. Demonstration of the advantages that are achieved and results showing the utility of the FPC devices for atomic and molecular analyses are given.