Integration of a carbon nanotube field emission electron gun for a miniaturized time-of-flight mass spectrometer

Stephanie A. Getty; Mary Li; Larry Hess; Nick Costen; Todd T. King; Patrick A. Roman; William B. Brinckerhoff; Paul R. Mahaffy

doi:10.1117/12.818939

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11 May 2009 Integration of a carbon nanotube field emission electron gun for a miniaturized time-of-flight mass spectrometer

Stephanie A. Getty, Mary Li, Larry Hess, Nick Costen, Todd T. King, Patrick A. Roman, William B. Brinckerhoff, Paul R. Mahaffy

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Proceedings Volume 7318, Micro- and Nanotechnology Sensors, Systems, and Applications; 731816 (2009) https://doi.org/10.1117/12.818939
Event: SPIE Defense, Security, and Sensing, 2009, Orlando, Florida, United States

Abstract

A carbon nanotube (CNT) field emission electron gun has been fabricated and assembled as an electron impact ionization source for a miniaturized time-of-flight mass spectrometer (TOF-MS). The cathode consists of a patterned array of CNT towers grown by catalyst-assisted thermal chemical vapor deposition. An extraction grid is precisely integrated in close proximity to the emitter tips (20-35 μm spacing), and an anode is located at the output to monitor the ionization beam current. Ultra-clean MEMS integration techniques were employed in an effort to achieve three improvements, relative to previous embodiments: reduced extraction voltage during operation to be resonant with gas ionization energies, enhanced current transmission through the grid, and a greater understanding of the fundamental current fluctuations due to adsorbate-assisted tunneling. Performance of the CNT electron gun will be reported, and implications for in situ mass spectrometry in planetary science will be discussed.

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Stephanie A. Getty, Mary Li, Larry Hess, Nick Costen, Todd T. King, Patrick A. Roman, William B. Brinckerhoff, and Paul R. Mahaffy "Integration of a carbon nanotube field emission electron gun for a miniaturized time-of-flight mass spectrometer", Proc. SPIE 7318, Micro- and Nanotechnology Sensors, Systems, and Applications, 731816 (11 May 2009); https://doi.org/10.1117/12.818939

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