Browse Prior Art Database

Original Publication Date: 1976-Feb-29
Included in the Prior Art Database: 2004-Mar-26

Publishing Venue

Xerox Disclosure Journal


A method is disclosed for providing preferential heating to a crucible, e.g.~ a tube crucible, without the need for radiation shields, In the past1 tube crucibles were usually heated by passing a high current through the structure, thereby heating the metal which in turn melts the material causing it to evaporate. The present method is a process whereby the crucible is constructed in such a way that the areas not in contact with the evaporant can be heated to a different temperature than the areas which are in contact with the evaporant. The principles of heat radiation are used. It may be desirable to have the areas in contact with the evaporant material operate at a cooler temperature than the areas of the crucible not in contact with the evaporant. Therefore, the latter areas should be treated to provide a highly reflective surface (bright or