Reflected electron distribution on anode surface of vacuum gap during electron beam bombardment: experimental results

Previously carried out analysis and simulation (see V.A. Shostak, 15th International Symposium on Discharges and Electrical Insulation, Darmstadt, Germany, p.726-9, 1992) of the reflection of an electron beam bombarding the anode through the hole in a cathode in vacuum gap (VG) with parallel electrodes and constant electrical field showed, that electrons distributions on anode surface have some peculiarities, in particular the availability of additional maximums and gradients, and dependence of their location and value on ratio of total beam energy and energy acquired by beam at VG. In this paper the results of experimental investigation of these distributions are presented (beam energy-15 keV, gap-40 mm, VG voltage-from 5 to 30 kV). In general, obtained results confirm qualitatively the peculiarities predicted by simulation.