A treatment which inhibits surface flashover in vacuum
A treatment is described which doubles the pulsed surface flashover potential of some insulator materials in vacuum. The test samples are short solid cylinders 1 cm in length and 6.35 cm in diameter. The flashover potential is measured by placing the sample between brass electrodes in a vacuum chamber at a pressure of 1 micro-Torr and applying a high voltage double exponential pulse with 1.5/135 ..mu..s time constants. The treatment consists of exposing a sample to 80,000 sparks from a spark plug in vacuum. For each material, an untreated and a treated sample are measured under identical conditions, and the results compared. Results on Lexan show an increase in flashover potential from 100 kV/cm to 170 kV/cm (limit of our Marx generator). On the machinable ceramic Macor, the results were 60 kV/cm untreated and 140 kV/cm treated. Surface analysis using Electron Spectroscopy for Chemical Analysis shows that the treatment alters the surface composition of the material. Also, the secondary electron emission coefficient has been measured for treated and untreated samples over a range of incident electron energies. The SEE changes dramatically after treatment. These measurements and the predictions of the existing theoretical model will be discussed.
- Research Organization:
- Texas Tech Univ., Lubbock (USA); Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6760111
- Report Number(s):
- UCRL-95087; CONF-860922-1; ON: DE87009564
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
420800* -- Engineering-- Electronic Circuits & Devices-- (-1989)
CURRENTS
CYLINDERS
ELECTRIC CURRENTS
ELECTRIC DISCHARGES
ELECTRICAL EQUIPMENT
ELECTRICAL INSULATORS
ELECTRON SPECTROSCOPY
EQUIPMENT
ESTERS
FLASHOVER
GLASS
LUCITE
MATERIALS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYACRYLATES
POLYMERS
POLYVINYLS
SPECTROSCOPY
SURFACE TREATMENTS
SYNTHETIC MATERIALS