Comparison of thermionic filament and carbon nanotube field emitter-based electron ionization sources in cycloidal coded aperture mass analyzers

Raul Vyas, Philip J. Herr, Tanouir Aloui, Kathleen Horvath, Matthew P. Kirley, Charles B. Parker, Adam D. Keil, James B. Carlson, Justin Keogh, Roger P. Sperline, M. Bonner Denton, M. Luisa Sartorelli, Brian R. Stoner, Michael E. Gehm, Jeffrey T. Glass, Jason J. Amsden

Research output: Contribution to journalArticle

Abstract

This work compares the coded aperture imaging performance of thermionic filament and carbon nanotube (CNT) field emitter-based electron sources in cycloidal-coded aperture mass spectrometers. The use of spatially coded apertures in mass spectrometry enables miniaturization by improving throughput without sacrificing resolution. CNT-based electron ionization sources for mass spectrometers provide several potential benefits over conventional thermionic emitters, including low voltage and low power consumption, room temperature operation, long lifetime, and ability to emit electrons in a pulsed mode. However, spatiotemporal variation in electron emission from CNTs is a major disadvantage. In this study, electron emission stability and spatiotemporal stability of the coded aperture image were compared for coded aperture cycloidal mass analyzers with either a CNT-based ion source or a thermionic filament-based ion source. We found that the thermionic filament-based ion source produced a significantly more stable coded aperture image than the CNT based ion source. The aperture image fluctuations in the CNT-based source are likely a result of adsorption and desorption of molecules on the CNT surface that cause local work function changes and induce spatiotemporal variation in electron emission and subsequent ion generation.

Original languageEnglish (US)
Article number116415
JournalInternational Journal of Mass Spectrometry
Volume457
DOIs
StatePublished - Nov 2020

Keywords

  • Carbon nanotubes
  • Coded apertures
  • Cycloidal mass analyzer
  • Field emission
  • Thermionic filament

ASJC Scopus subject areas

  • Instrumentation
  • Condensed Matter Physics
  • Spectroscopy
  • Physical and Theoretical Chemistry

Fingerprint Dive into the research topics of 'Comparison of thermionic filament and carbon nanotube field emitter-based electron ionization sources in cycloidal coded aperture mass analyzers'. Together they form a unique fingerprint.

  • Cite this

    Vyas, R., Herr, P. J., Aloui, T., Horvath, K., Kirley, M. P., Parker, C. B., Keil, A. D., Carlson, J. B., Keogh, J., Sperline, R. P., Denton, M. B., Sartorelli, M. L., Stoner, B. R., Gehm, M. E., Glass, J. T., & Amsden, J. J. (2020). Comparison of thermionic filament and carbon nanotube field emitter-based electron ionization sources in cycloidal coded aperture mass analyzers. International Journal of Mass Spectrometry, 457, [116415]. https://doi.org/10.1016/j.ijms.2020.116415