Suppression of vacuum breakdown using thin film coatings
The use of thin film coatings for increasing the breakdown voltage in a parallel-plane high-voltage gap has been investigated. Both metallic and ceramic thin films were deposited at varying thicknesses and deposition conditions on a screen cathode using ion-beam sputtering. Improvements in breakdown voltage were observed for nearly any type of deposited film, with significant variations in breakdown voltage depending on film thickness and oxygen and partial pressure during ceramic film deposition. For 500 nm thick metallic or oxide films, breakdown voltage was nearly doubled compared to the bare stainless steel screen, which is attributed to the burying of surface imperfections on the cathode. For 200 nm thick films, the covering of imperfections is less effective; however, high breakdown voltages can still be obtained by choosing an appropriate oxygen partial pressure during film deposition. Electric fields as high as 60 kV/mm were sustained across a 1 mm gap for 10 {mu}sec pulses; lesser fields could be sustained for as long as 10 ms. These coatings allowed for the successful study of a planar liquid metal ion source.
- OSTI ID:
- 67885
- Report Number(s):
- CONF-9310400--; CNN: Contract 69-5698; Grant F49629-92-J-0157P00001
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 13 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
- Country of Publication:
- United States
- Language:
- English
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