Charged particle gun, charged particle beam system, and lock nut

A charged particle beam system comprising:

• a charged particle gun;
• an optical processing unit configured to optically process a charged particle beam emitted from the charged particle gun;
• a sample holding unit configured to hold a sample to be irradiated with the charged particle beam;
• and
• a computer system configured to control the optical processing unit,
• wherein the charged particle gun includes:
• a charged particle source;
• a bolt having the charged particle source attached thereto;
• a nut including a first surface and a second surface on an opposite side of the first surface and configured to hold the charged particle source by being screwed onto the bolt having the charged particle source attached thereto;
• and
• a nut seat surface configured to contact the second surface of the nut,
• wherein the nut includes:
• the first surface, the second surface, an outer surface, and an inner surface;
• a screw thread section provided on a portion of the inner surface and formed with a plurality of screw threads to be screwed with the bolt;
• an inclination adjustment section configured to be able to adjust an inclination angle of the charged particle source with respect to the nut seat surface, the charged particle source being in a state of being held by the nut;
• and
• a lock section configured to prevent loosening of a screwed state between the nut and the bolt, wherein:
• the inner surface of the nut includes:
• the screw thread section;
• and
• a non-screw thread section having an inner diameter larger than an inner diameter of the screw thread section, and
• the inclination adjustment section includes:
• a first slit formed to be penetrated from a portion of the outer surface to a portion of the non-screw thread section;
• an inclination adjustment screw;
• a first portion positioned between the first slit and the second surface;
• a second portion positioned between the first slit and the first surface;
• and
• a first screw hole having the inclination adjustment screw screwed thereinto, the first screw hole being formed to be penetrated from the first surface to the first slit in the second portion,
• wherein a tip of the inclination adjustment screw expands the first slit and presses the nut seat surface via the first portion, thereby changing the inclination angle of the charged particle source with respect to the nut seat surface.

A lock nut comprising:

• a first surface;
• a second surface on an opposite side of the first surface;
• a nut hole penetrated from one side of the first surface and the second surface to the other side thereof;
• an inner surface which is an outer edge of the nut hole;
• an outer surface on an opposite side of the inner surface;
• a screw thread section provided on a portion of the inner surface and formed with a plurality of screw threads;
• an inclination adjustment section configured to be able to adjust an inclination angle of the nut hole with respect to a nut seat surface facing the second surface;
• and
• a lock section configured to prevent loosening of a screwed state of a bolt screwed into the nut hole, wherein:
• the inner surface includes:
• the screw thread section;
• and
• a non-screw thread section having an inner diameter larger than an inner diameter of the screw thread section, and
• the inclination adjustment section includes:
• a first slit formed to be penetrated from a portion of the outer surface to a portion of the non-screw thread section;
• an inclination adjustment screw;
• a first portion positioned between the first slit and the second surface;
• a second portion positioned between the first slit and the first surface;
• and
• a first screw hole having the inclination adjustment screw screwed thereinto, the first screw hole being formed to be penetrated from the first surface to the first slit in the second portion,
• wherein a tip of the inclination adjustment screw presses the nut seat surface via the first portion, thereby changing an inclination angle of a nut axis with respect to the nut seat surface.