Design and initial characterization of a glow discharge atomic emission instrument for macro-scale elemental composition mapping of solid surfaces

An instrument intended for rapid, accurate, precise, macro-scale (i.e. up to many tens of square centimeters) elemental composition mapping of solid surfaces has been designed and constructed. The spatial resolution provided by the instrument, on the order of 1 mm at best, is coarse by today's standards but is appropriate for selected analytical problems. The instrument is based on a novel glow discharge atomic emission device capable of sustaining multiple discharges simultaneously. Each discharge exhibits atomic emission characteristic of the sample surface beneath it. Using Hadamard transform spatial imaging, the emissions are selectively multiplexed, and the individual emission intensities are recovered from the multiplexed data through matrix multiplication. In this publication, the instrument is described, and its performance for elemental composition mapping is demonstrated. The data indicate that internal standardization should be employed to reduce the likelihood of mapping errors.