Development of directly and indirectly heated thermionic electron beam sources at EBSDL

The development of thermionic electron guns is of significant importance in electron beam technology. The paper is primarily concerned with the design, fabrication and experimentation of electron beam sources developed by our research group at electron beam sources development laboratory (EBSDL). This includes directly and indirectly heated thermionic electron beam sources as well as high power line source electron guns. The important features of optimized gun designs and performance characteristics are briefly outlined and their results are presented. These guns are currently being used for melting, welding and evaporation and heat treatment.