Influence of the filament potential wave form on the sensitivity of glass‐envelope Bayard–Alpert gages
作者:
Patrick J. Abbott,
J. Patrick Looney,
期刊:
Journal of Vacuum Science&Technology A: Vacuum, Surfaces, and Films
(AIP Available online 1994)
卷期:
Volume 12,
issue 5
页码: 2911-2916
ISSN:0734-2101
年代: 1994
DOI:10.1116/1.578964
出版商: American Vacuum Society
关键词: BAYARD−ALPERT GAGES;SENSITIVITY;HIGH VACUUM;ULTRAHIGH VACUUM;GLASS;PLATINUM;FILAMENTS;ELECTRIC POTENTIAL;WAVE FORMS;glass;Pt
数据来源: AIP
摘要:
Nonlinearities of ∼10%–15% in the sensitivity of glass envelope Bayard–Alpert gages (BA gages) have been observed in the pressure range 10−7–10−2Pa. These nonlinearities were studied in modified BA gage tubes with platinum coatings on their inner glass surfaces by measuring the equilibrium potential of the platinum coating as a function of pressure. The sensitivities of the gage systems (gage tube plus controller) were found to depend on the inner surface potential, and this potential was found to depend on pressure and on the details of the filament potential waveform provided by the gage controller. It was found that the nonlinearities could be minimized by holding the inner surface to a fixed direct‐current (dc) potential, by modifying the alternating‐current filament potential wave form, or by using a controller that provides a noise‐free dc filament‐heating current.
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