X-Ray Pinhole Photographic Evidence of Multiple Field-Emission Sources

Abstract

An investigation was carried out to exhibit the existence of localized field-emitting areas on nickel electrode surfaces. To this end, a system consisting of concentric cylindrical electrodes, whose radial electrode spacing and inner radius were 7.75 and 16 mm, respectively, and which had an effective length of 12 cm and a cathode area of 130 sq cm, was used as a source to expose x-ray films through a pinhole setup. The resultant images clearly show the existence of discrete electron beams bombarding the anode. There were an average of 3.5 spots per square centimeter at a gross field of 157 kV/cm. A number of Fowler-Nordheim plots were taken, and the usual result was a straight line. The x-ray sources from the anode were also found to be smaller than 0.1 mm.