| 摘要 |
Currently, there is no noise-proof cover, particularly noise-proof cover used in a clean room, which absorbs noise by a structure specialized for an estimated frequency of noise produced by environmental noise. Therefore, efficient noise absorption is still difficult. Accordingly, the invention provides a charged particle beam apparatus in which either a first noise absorber which provides noise absorbing performance specialized for a first frequency range including the natural frequency of the charged particle beam apparatus as reference, or a second noise absorber which provides noise absorbing performance specialized for a second frequency range including the frequency of acoustic standing waves generated within the cover as reference, or both of the first and second noise absorbers is/are disposed within a cover of the charged particle beam apparatus.
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