Conventional triode ionization gauge with carbon nanotube cold electron emitter
Schematic illustration of CNT-based conventional triode ionization gauge. , collector current; , grid current. The gauge is operated with the collector at a negative voltage, the grid at a positive voltage, and the CNT cathode at ground potential.
(a) SEM image of the CNT electron emitter. (b) characteristics of the CNT electron emitter with collector voltage; . The inset is the corresponding Fowler-Nordheim plot (Ref. 11).
Electrical characteristics of the CNT-based gauge in the vacuum range from in nitrogen with and . (a) The system pressure. (b) Stability of the electron current. (c) Stability of the ratio of the ion current to the electron current. (a)–(c) are in the same time scale.
Variation of the CNT-based gauge’s sensitivity factor with the collector voltage and the grid voltage at in nitrogen. (a) Sensitivity factor vs the collector voltage with . (b) Sensitivity factor vs the grid voltage with . The arrows in (b) indicate the electron currents at the corresponding grid voltages.
Linearity dependence of the ratio of the ion current to the electron current on the system pressure for the CNT-based gauge. Curve (A): cylindrical shell ion collector; the electrode potentials are and ; the slope of the linear portion is . Curve (B): 85% transparency mesh ion collector; the electrode potentials are and ; the slope of the linear portion is .
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