Diverging beam electron gun for a toxic remediation device with a dome-shaped focusing electrode

摘要

An electron gun for use in remediation of hazardous volatile organic compounds is provided. The electron gun comprises a cathode having a concave emitting surface and a dome-shaped focusing electrode concentrically surrounding the emitting surface. The focusing electrode has an inwardly protruding lip portion that extends at least partially into a beam focusing region defined in front of the emitting surface. A target grid is spaced from the cathode and a negative voltage is applied between the emitting surface and the target. The target grid has a surface area that is substantially larger than an associated surface area of the emitting surface. An electron beam is provided by the emitting surface in response to the negative voltage, and is focused into a broad diverging beam by the focusing electrode. The electron gun may be configured for temperature limited emission or space charge limited emission.