KβX-Ray Emission from Solid and Liquid Aluminum

The $K\beta$ emission band from solid and liquid aluminum has been studied using 6-kV electrons and a flat crystal x-ray spectrometer equipped with a flow counter. The $K\beta$ band from the solid is similar to that recorded by other authors: very asymmetrical, rising rapidly on the short-wavelength side and tailing off slowly to longer wavelengths. At the melting point, the curve is virtually identical to the obtained from the solid. At higher temperatures, estimated to be several hundred degrees above the melting point, $K\beta$ becomes symmetrical and very narrow, of approximately the same width as lines not involving the conduction band. It is not clear whether this narrow line originates from the surface of the liquid aluminum or from a dense gaseous aluminum layer at the surface.