Coaxial source for electron beam welding etc. - has cathode anode chamber cathode structure with central emission apertures

摘要

Increased effective energy electron source of coaxial construction comprises an accelerator electrode (2) with an aperture (3) through to the emission cathode (4) assembly with its emission channel (5) leading to an emitting chamber cathode structure (8,7). The chamber cathode (7) is a soft magnetic material lined with a tube (15) of material having a higher photo emission coefficient. A central ring anode (6) between cathodes (4,7) and their aperture faces (11,12) form a chamber (14) in which Penning discharges can be initiated.