Date of Award
Doctor of Philosophy (PhD)
Electrical & Computer Engineering
Karl H. Schoenbach
Hani E. Elsayed-Ali
Gary E. Copeland
Ravindra P. Joshi
Field emission of electrons is the major cause of electrical breakdown in high voltage systems in vacuum. The highest hold-off electric field of the carefully polished and cleaned stainless steel cathodes was increased to 70MV/m. Thin silicon monoxide, SiOx, cathode coatings reduced field emission and increased the hold-off field further. Coating the stainless steel cathodes with 2μ SiOx reduced the field emission current by at least two orders of magnitude at field of 50MV/m and increased the breakdown field to 140MV/m, doubling the breakdown voltage.
The increase in hold-off voltage with SiOx coatings is discussed in terms of electron transport within the coating. Measurements indicate that current in SiOx at high fields is controlled by Frenkel-Poole electron emission from deep centers located about 1eV below the conduction band. Field emission current is limited at the coating-vacuum interface due to an accumulation of filled electron traps.
Allen, Raymond J..
"Field Emission and Breakdown Processes in Vacuum Gaps with SiO(X)-Coated Cathodes"
(1998). Doctor of Philosophy (PhD), Dissertation, Electrical & Computer Engineering, Old Dominion University, DOI: 10.25777/fs7a-n845