CHARGED PARTICLE BEAM APPARATUS

摘要

Conventionally, soundproof covers, especially soundproof covers to be used in a clean room, did not assume frequency of noise brought about by environmental noise, and did not absorb that noise with a structure specialized to meet that frequency, and therefore, could not absorb sound efficiently. Provided to solve this problem is a charged particle beam apparatus characterized in having installed, within a cover (301) of the charged particle beam apparatus, a first sound absorber (1001) having the sound absorbing property thereof specialized to meet a first frequency range that is based on the natural frequency of the charged particle beam apparatus, and/or a second sound absorber (1003) that is specialized to meet a second frequency range that is based on the frequency of an acoustic standing wave to be generated within the cover (301).