Carbon nanotube electron ionization source for portable mass spectrometry

Cold cathode carbon nanotubes (CNTs) are used in a low-voltage quadrupole ion trap mass spectrometer and shown to be a viable low-power alternative to filament sources for portable mass spectrometry instrumentation. No heating is necessary, and the power consumption depends only on the switching characteristics of the electronics. The CNT electron sources are mounted directly in the ring electrode, and their performance is compared directly with a filament source also mounted in the ring electron. Up to a 5 × 10 ^-4 Torr CO ₂ environment, reflecting conditions expected during operation in a Mars atmosphere, the CNT emitters may provide up to 1 μA of current over more than 200 h.