Microscopic and macroscopic material property effects on ultraviolet-laser-induced flashover of angled insulators in vacuum

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · IEEE Trans. Plasma Sci.; (United States)

DOI:https://doi.org/10.1109/27.3846· OSTI ID:7123142

Enloe, C L; Gilgenbach, R M

Flashover of electrically stressed polymeric insulators in vacuum has been induced by ultraviolet radiation from an excimer laser (KrF). Flashover behavior is a relatively strong function of integrated fluence up to the time of flashover initiation, and virtually independent of applied power or pulse time. Flashover is induced by moderate fluence (10 - 150 mJ/cm/sup 2/) of intense (0.4 - 6 MW/cm/sup 2/) ultraviolet at 248 nm at electric field stress considerably below the static breakdown stress. The critical fluence required to initiate flashover is a function of the electric field stress, the insulating material, and the geometry of the dielectric/vacuum interface. The unconventional insulator geometry (in which electrons are accelerated toward the insulator surface) is more tolerant than the conventional geometry by nearly a factor of 2 in fluence. Insulator materials tested were polyethylene, polystyrene, acrylic, nylon-6, acetal, PVC, and teflon. The critical fluence is correlated to the microscopic and macroscopic material properties; results show that insulating materials with high dielectric constants and low secondary electron emission coefficients exhibit superior tolerance to ultraviolet radiation. Of the materials tested, nylon exhibited the highest critical fluence in both the conventional and the unconventional geometries. A theory of ultraviolet-induced insulator flashover is developed.

• Research Organization: Intense Energy Beam Interaction Lab., Dept. of Nuclear Engineering, Univ. of Michigan, Ann Arbor, MI (US)
• OSTI ID: 7123142
• Journal Information: IEEE Trans. Plasma Sci.; (United States), Journal Name: IEEE Trans. Plasma Sci.; (United States) Vol. 16:3; ISSN ITPSB
• Country of Publication: United States
• Language: English

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CURRENTS
DATA
DIELECTRIC MATERIALS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
ELECTRIC FIELDS
ELECTRICAL EQUIPMENT
ELECTRICAL INSULATORS
ELECTROMAGNETIC RADIATION
EQUIPMENT
EXCIMER LASERS
FLASHOVER
FLUORINATED ALIPHATIC HYDROCARBONS
GAS LASERS
GEOMETRY
HALOGENATED ALIPHATIC HYDROCARBONS
INFORMATION
LASER-PRODUCED PLASMA
LASERS
MATERIALS
MATERIALS TESTING
MATHEMATICS
NUMERICAL DATA
NYLON
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASMA
PLASTICS
POLYAMIDES
POLYETHYLENES
POLYMERS
POLYOLEFINS
POLYSTYRENE
POLYTETRAFLUOROETHYLENE
POLYVINYLS
RADIATIONS
SYNTHETIC MATERIALS
TEFLON
TESTING
THEORETICAL DATA
ULTRAVIOLET RADIATION
VACUUM SYSTEMS