A Micro Ionizer for Portable Mass Spectrometers using Double-gated Isolated Vertically Aligned Carbon Nanofiber Arrays

We report micro-fabricated double-gated vertically aligned carbon nanofiber (CNF) arrays for ionization of gasses in low power portable mass spectrometers. The devices can be operated in one of two modes - electron impact ionization (EII ) or field ionization (FI). When operated as electron impact ionizer, power dissipation was reduced from >1 W typical of thermionic emission based electron impact ionizers to <100 mW. When operated as a field ionizer, the turn-on voltage for field ionization is reduced from 5-10 kV typical of ungated ionizers to 350 V.