HIGH VOLTAGE BREAKDOWN STUDY

The work reported describes a five-year program to study high voltage breakdown in vacuum and the factors which influence it with particular application to problems encountered in the development of high power vacuum tubes which operate in the range 100 to 300 kV. Factorial and statistical design was used because it provided a powerful tool for the analysis of the results and enabled information to be derived from a minimum number of experiments on both the effects of the individual factors and on the degree of interaction among factors. The test apparatus was designed and fabricated - bakeable vacuum chamber with control and monitoring apparatus (voltage, current, radiation and pressure). Six major experiments were carried out: Preliminary, Pilot, Block of Eight, Block of Thirty-Two, Energy Conditioning and Barium Contamination Experiments. Factors studied included: Environmental Factors (residual gas, temperature, envelope, magnetic field, contamination, oxide films); Fields, Geometry and Area; Electrode Materials and Surface Properties; Electrical Circuitry, and Energy and Experimental Factors. The results are analyzed and discussed. See also Final rept. AD0711558.