| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam current attenuator easily manufactured and capable of easily adjusting a beam current of charged particle beams. SOLUTION: This beam current attenuator 1 is provided with a metal plate 2 provided with a plurality of slits 4, and a supporting shaft 3 supporting the metal plate 2 and movable reciprocating in an axial direction. A plurality of slits 4 are provided at the metal plate 2 parallel with one another, and the width dimension of the slits 4 is continuously reduced toward the supporting shaft 3 along the longitudinal direction. Consequently, when the metal plate 2 is irradiated with the charged particle beams 5, the charged particle beams 5 pass through only the slits 4 but do not pass through other metal parts. The beam current can thereby be attenuated, and the width dimension of the slits 4 is changed by reciprocating the metal plate, thus changing the attenuation factor of the beam current.
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