George, Patricia M. and Swanson, Mark N. and Beauchamp, J. L. (1979) Simple pressure gauge for uranium hexafluoride. Review of Scientific Instruments, 50 (12). pp. 1640-1644. ISSN 0034-6748 http://resolver.caltech.edu/CaltechAUTHORS:20120725-145242342
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A sensitive detector and pressure gauge for uranium hexafluoride in high‐vacuum systems is described. Negative surface ionization of UF_6 occurs on ribbon filaments operated at temperatures too low for electron emission to be significant. The ion current measured on a cylindrical collector surrounding the filament assembly varies regularly with UF_6 pressure below 10^(−3) Torr. Different filament materials are considered, including rhenium, thoriated tungsten, and platinum. Rhenium is found to be the most satisfactory material for operation of diode emitters as a pressure gauge. Gauge constants (in A Torr^(−1)) are derived from comparing negative surface ionization currents with the response of a capacitance manometer and are shown to be independent of temperature within a reasonable operating range. The effects of exposing the rhenium filament to various gases is considered, and it is shown that brief exposure to acetylene substantially improves the operating characteristics of the gauge.
|Additional Information:||© 1979 American Institute of Physics. Received 18 September 1978; accepted for publication 6 July 1979. Online Publication Date: 6 August 2008. This work was supported in part by the United States Department of Energy under Grant No. E(04-3)767-8.|
|Subject Keywords:||PRESSURE GAGES, URANIUM HEXAFLUORIDE, SENSITIVITY, SURFACE IONIZATION, HIGH VACUUM, FILAMENTS, ELECTRON EMISSION, IONS, ELECTRIC CURRENTS, CYLINDRICAL CONFIGURATION, THORIATED TUNGSTEN, PLATNUM, THENIUM, DATA, CAPACITORS, TEMPERATURE DEPENDENCE, ACETYLENE|
|Classification Code:||PACS: 34.80.Gs, 07.30.Dz|
|Official Citation:||Simple pressure gauge for uranium hexafluoride Patricia M. George, Mark N. Swanson, and J. L. Beauchamp Rev. Sci. Instrum. 50, 1640 (1979); http://dx.doi.org/10.1063/1.1135745|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||30 Jul 2012 16:29|
|Last Modified:||26 Dec 2012 15:44|
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