| 摘要 |
Apparatus for blanking an electron or ion beam comprises a pair of blanking plates 2,3. A stopper 4 is mechanically and electrically connected to one blanking plate. By applying a suitable bias to the plates 2,3 and stopper 4, a beam 7 passing between the plates is deflected so that electrons or ions are stopped by the stopper 4. The stopper 4 may comprise a cavity 6 into which electrons or ions are deflected, the cavity 6 having a knife edge at its entrance. The cavity 6 may be formed by drilling a hole in the plate 2 from one face, chamfering the edge of the face and attaching a wedge to the chamfer to cover a part of the entrance of the hole. Alternatively, the cavity may be formed by drilling an angled hole from one face which stops a given distance form the opposite face, and then cutting a recess in the opposite face which breaks through to the hole. |
