| 摘要 |
Charged-particle-beam (CPB) optical systems are disclosed that exhibit reduced eddy currents forming in the beam tube of the system. The eddy currents otherwise would degrade beam-control response time of the system. In an embodiment, the beam tube defines at least one slit in an "eddy-current zone" of the beam tube adjacent an energizable coil of the system, such as a deflector coil. The slit(s) is situated so as to divide the eddy-current zone. The slit(s) extends at least part way through the thickness dimension of the beam tube and can be formed using conventional machine tools, wire cutting, or electrical-discharge machining, or other suitable technique. Compared to an eddy-current zone lacking a slit, the divided eddy-current zones produced by the slit(s) have substantially reduced overall area, thereby reducing eddy current in the beam tube and allowing a corresponding increase in beam-control speed.
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