A Source of Radially Converging Low-Energy High-Current Electron Beams

The design and some characteristics of a source of radially converging low-energy (5–25 keV) high-current electron beams of microsecond pulse duration, which is aimed at surface modification of cylindrical parts and samples, are presented. The cathode unit of the source is a duralumin ring with an 8-cm inner diameter in which which 18 resistively decoupled arc plasma sources are built-in. The operability of the source electron gun in the vacuum-diode (with a residual-gas pressure of ~0.013 Pa) and gas-filled-diode modes at pressures of 0.05–0.09 Pa has been demonstrated. The beam energy density on the 1-cm-diameter anode is sufficient for surface melting of copper (the threshold of pulsed copper melting is 5–5.5 J/cm2 at a pulse duration of 2–3 µs) at a 17-kV charging voltage of the high-voltage pulse generator that powers the electron gun.