Apparatus for the Measurement of Breakdown Voltage Between Metal Electrodes in Vacuum

This paper describes apparatus used for the measurement of breakdown voltages between electrodes in vacuum with potentials up to the order of 500 kv. The use of a direct voltage of this magnitude required special shielding to limit electrical stresses in the lead-in bushing of the vacuum tank. The source of power was an electrostatic belt generator with a corona-leak voltage control. Voltage was measured with a xylene alcohol high resistance voltmeter. Incidental work with stand-off insulators in vacuum is described. The results of a series of breakdown measurements are shown with a curve.