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Title: Cold cathode field emitter array on a quadrupole mass spectrometer: Route to miniaturization

Abstract

We have improved the quadrupole mass spectrometer by substituting the conventional hot filament electron source by a field emitter array (FEA). Elimination of the hot filament avoids a number of common problems, including thermal cracking of delicate molecules, outgassing of the filament itself and nearby components, high power requirements for the filament, large size, stray light, stray magnetic fields, contamination by thoria and tungsten, and a long warm-up time. The advantages are clearest for portable applications where power requirements dominate. Here, the power savings are not just in eliminating the filament supply, but more important in reducing the largest component of the system, the vacuum pump. This comes about because the filament is the primary gas load and because chemical reactions taking place on it require fast pumping to keep the products from interfering with the spectra. Comparison between hot filament and cold cathode FEA ionization is made using a quadrupole mass spectrometer fitted with both electron sources, independently controlled. The FEA advantage is strongest when the ultrahigh vacuum system is throttled to a low pumping speed, mimicking a portable system with a small pump. FEAs also enable miniaturization and a corresponding decrease in pump size. Moreover, with miniaturization, shortermore » mean free paths and consequently higher working pressures can be tolerated further decreasing pump requirements. {copyright} {ital 1999 American Vacuum Society.}« less

Authors:
 [1]
  1. Sandia National Laboratories, Livermore, California 94550 (United States)
Publication Date:
OSTI Identifier:
686527
Resource Type:
Journal Article
Journal Name:
Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena
Additional Journal Information:
Journal Volume: 17; Journal Issue: 5; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
66 PHYSICS; 44 INSTRUMENTATION, INCLUDING NUCLEAR AND PARTICLE DETECTORS; CATHODES; ELECTRON SOURCES; MOLYBDENUM; FIELD EMISSION; COLD CATHODE TUBES; MASS SPECTROMETERS; MINIATURIZATION; QUADRUPOLAR CONFIGURATIONS

Citation Formats

Felter, T.E. Cold cathode field emitter array on a quadrupole mass spectrometer: Route to miniaturization. United States: N. p., 1999. Web. doi:10.1116/1.590859.
Felter, T.E. Cold cathode field emitter array on a quadrupole mass spectrometer: Route to miniaturization. United States. doi:10.1116/1.590859.
Felter, T.E. Wed . "Cold cathode field emitter array on a quadrupole mass spectrometer: Route to miniaturization". United States. doi:10.1116/1.590859.
@article{osti_686527,
title = {Cold cathode field emitter array on a quadrupole mass spectrometer: Route to miniaturization},
author = {Felter, T.E.},
abstractNote = {We have improved the quadrupole mass spectrometer by substituting the conventional hot filament electron source by a field emitter array (FEA). Elimination of the hot filament avoids a number of common problems, including thermal cracking of delicate molecules, outgassing of the filament itself and nearby components, high power requirements for the filament, large size, stray light, stray magnetic fields, contamination by thoria and tungsten, and a long warm-up time. The advantages are clearest for portable applications where power requirements dominate. Here, the power savings are not just in eliminating the filament supply, but more important in reducing the largest component of the system, the vacuum pump. This comes about because the filament is the primary gas load and because chemical reactions taking place on it require fast pumping to keep the products from interfering with the spectra. Comparison between hot filament and cold cathode FEA ionization is made using a quadrupole mass spectrometer fitted with both electron sources, independently controlled. The FEA advantage is strongest when the ultrahigh vacuum system is throttled to a low pumping speed, mimicking a portable system with a small pump. FEAs also enable miniaturization and a corresponding decrease in pump size. Moreover, with miniaturization, shorter mean free paths and consequently higher working pressures can be tolerated further decreasing pump requirements. {copyright} {ital 1999 American Vacuum Society.}},
doi = {10.1116/1.590859},
journal = {Journal of Vacuum Science and Technology. B, Microelectronics Processing and Phenomena},
number = 5,
volume = 17,
place = {United States},
year = {1999},
month = {9}
}