Charged particle beam device

A charged particle beam device comprising:

• a stage on which a sample is to be placed;
• a charged particle optical system including a charged particle source and an objective lens configured to focus a charged particle beam from the charged particle source onto the sample;
• and
• a detector disposed between the objective lens and the stage and configured to detect electrons emitted by an interaction between the charged particle beam and the sample, wherein
• the stage, the charged particle optical system, and the detector are housed in a vacuum housing,
• the detector includes a scintillator, a solid-state photomultiplier tube, and a light guide provided between the scintillator and the solid-state photomultiplier tube, and an area of a light receiving surface of the scintillator is larger than an area of a light receiving surface of the solid-state photomultiplier tube,
• the charged particle beam device further comprises:
• a conductive housing configured to house the detector with the light receiving surface of the scintillator of the detector exposed;
• and
• a housing potential setting power supply configured to apply a predetermined voltage to the conductive housing,
• a surface of the scintillator of the detector is coated with a conductive material,
• the conductive housing and the conductive material are electrically connected, and
• focus adjustment of the charged particle beam from the charged particle optical system is executed by controlling the voltage to be applied to the conductive housing.