Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum
- State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China)
- Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)
The luminescence evolution phenomena from alumina ceramic surface in vacuum under high voltage of direct and alternating current are reported, with the voltage covering a large range from far below to close to the flashover voltage. Its time resolved and spatial distributed behaviors are examined by a photon counting system and an electron-multiplying charge-coupled device (EMCCD) together with a digital camera, respectively. The luminescence before flashover exhibits two stages as voltage increasing, i.e., under a relative low voltage (Stage A), the luminescence is ascribed to radiative recombination of hetero-charges injected into the sample surface layer by Schottky effect; under a higher voltage (Stage B), a stable secondary electron emission process, resulting from the Fowler-Nordheim emission at the cathode triple junction (CTJ), is responsible for the luminescence. Spectrum analysis implies that inner secondary electrons within the surface layer of alumina generated during the SSEE process also participate in the luminescence of Stage B. A comprehensive interpretation of the flashover process is formulated, which might promote a better understanding of flashover issue in vacuum.
- OSTI ID:
- 22611542
- Journal Information:
- AIP Advances, Vol. 6, Issue 6; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALTERNATING CURRENT
ALUMINIUM OXIDES
CERAMICS
CHARGE-COUPLED DEVICES
CONNECTORS
ELECTRIC CONTACTS
ELECTRON EMISSION
FLASHOVER
LAYERS
LUMINESCENCE
SCHOTTKY EFFECT
SEMICONDUCTOR JUNCTIONS
SPECTRA
SUPERCONDUCTING JUNCTIONS
SURFACES
TIME RESOLUTION
PHOTON COUNTING