Abstract: Vapor source material such as uranium, which is to be dropped into a melt in an evaporator, is made into many balls of identical diameters and placed inside a container. An elongated sloping pipe is connected to the container and leads to the evaporator such that these balls can travel sequentially therealong by gravity. A metering valve in this pipe for passing these balls one at a time is opened in response to a signal when it is ascertained by a detector that there is a ball ready to be passed. A gate in the pipe near the evaporator momentarily stops the motion of the traveling ball and is then opened to allow the ball drop into the melt at a reduced speed.

Abstract: Apparatus and method for supplying feedstock to a reservoir containing material having a portion which is heated to a molten condition and vaporized by an electron beam. The electron beam is supplied from a heated filament and directed to impact on the vapor source material by electric and magnetic fields. The feedstock is suspended above a portion of the reservoir out of the path of the electron beam. Skip electrons along with some secondary electrons emitted from the surface of the material in the vicinity of the region of electron beam impact, together with radiant heating therefrom, are utilized to melt an exposed portion of the feedstock, allowing it to drip into the reservoir, and replenish the supply of material which is depleted by vaporization. Vaporization is maintained substantially uniform from the region of electron beam impact and splatter of the feedstock is largely avoided.