Abstract: A method is disclosed for shaping parts made of tungsten and of tungsten with thoria. The method involves machining the parts with a machining apparatus wherein the machining tool is made of diamond or material of which tungsten carbide is the main phase, the material having a hardness of greater than about 91 Rockwell A, the machining being done at a speed of from about 40 to about 120 surface feed per minute, and a feed rate of from about 0.0002 to about 0.006 inches per revolution. Machining of parts made of tungsten is done with cooling with a halocarbon solvent. Machining of parts made of tungsten and thoria can be done with or without cooling.

Abstract: A PIN photodiode structure uses direct side entry into the I region, thus permitting the use of thicker P and N regions with a comparatively thin I region without sacrificing speed and results in more constant spatial distribution upon carrier generation and longer wave length devices with conventional speeds or smaller devices at faster speeds, and may be integrated on the same chip with associated circuits.