| 摘要 |
An electron gun (1) includes an emitter (2), a tubular support (3) and an adaptor (4) for receiving the emitter. The adaptor includes a tapered plugging surface (7) and the tubular support includes a correspondingly tapered seating surface (9) for receiving the plugging surface. The plugging surface and seating surface have conical profiles which help to position the adaptor concentrically with the support. An extractor electrode (5) may be seated in another adaptor (6) which itself is seated in the support (3) by a similar arrangement of correspondingly tapered surfaces (8),(10). The gun may be an electron gun or an ion gun, e.g. for electron beam lithography. The arrangement facilitates proper alignment and spacing of the emitter (2) and the extractor electrode (5). |
