| 摘要 |
The present invention relates to a plasma electron source apparatus (150). The apparatus comprises a cathode discharge chamber (100) in which a plasma is generated, an exit hole (120) provided in the cathode discharge chamber from which electrons from the plasma (107) are extracted by an accelerating field provided between the cathode discharge chamber (100) and an anode (104), at least one plasma confinement device (e.g. an electromagnetic coil 103), and a switching mechanism (190) for switching the at least one plasma confinement device between a first value allowing for electron extraction from the plasma and a second value prohibiting electron extraction from the plasma. Associated methods are also provided, in particular use of the apparatus (150) for forming a three dimensional article through successive fusion of parts of at least one layer of a powder bed provided on a work table. |
