Observing Performance of Individual Metal-Coated Silicon Field-Emitters in an X-ray Generator

The performance of a field-enhanced emitter (FEE) array in an enclosed and ex-situ operated device has long been known to deviate from the ideal characteristics observed in laboratory settings. Here we report on the performance and failure mechanisms measured in FEE arrays operating in high-voltage sealed x-ray generators. The emitters are fabricated from etched silicon forming pyramids which are coated with metal. Unlike many previously reported arrays, here the pitch is large (1cm) and affords easy measurement and diagnosis of individual emitters. We report on emitter performance and likely causes of deviations from ideal, including the impact of anode treatment, emitter geometry and catastrophic failure mechanisms.