A charged particle beam system can include a vacuum chamber, a specimen holder for holding a specimen within the vacuum chamber, and a charged particle column. The charged particle column can include a charged particle source for producing a beam of charged particles along an optical axis and a magnetic immersion lens for focusing the beam of charged particles. The magnetic immersion lens can include a first lens pole disposed adjacent a first surface of the specimen, an excitation coil surrounding the first lens pole, and a counterpole disposed adjacent a second surface of the specimen, the counterpole including one or more magnets disposed on the counterpole.

A charged particle beam system can include a vacuum chamber, a specimen holder for holding a specimen within the vacuum chamber, and a charged particle column. The charged particle column can include a charged particle source for producing a beam of charged particles along an optical axis and a magnetic immersion lens for focusing the beam of charged particles. The magnetic immersion lens can include a first lens pole disposed adjacent a first surface of the specimen, an excitation coil surrounding the first lens pole, and a counterpole disposed adjacent a second surface of the specimen, the counterpole including one or more magnets disposed on the counterpole.

A Wien filter includes a cylindrical yoke, a plurality of magnetic poles arranged at intervals along an inner periphery of the yoke, the magnetic poles each joined at one end thereof to the yoke, a coil wound on each of the plurality of magnetic poles, and an electrode disposed at the other end of each of the plurality of magnetic poles, with an insulator between the electrode and the magnetic pole. The magnetic poles each has a recess at the other end thereof, and the insulator and the electrode may be disposed in the recess.

A fine-adjustable charged particle lens comprises a magnetic circuit assembly including permanent magnets, a yoke body, and a shunting device comprising a shunting component, and this assembly surrounds a beam passage extending along the longitudinal axis (cx). The shunting device is placed in the yoke body besides the permanent magnets and may be composed of several sector components, comprising different high magnetically permeable materials. The permanent magnet and the yoke body form a magnetic circuit having at least two gaps, in order to generate a magnetic field reaching inwards into the beam passage, into which a sleeve insert having electrostatic electrodes can be inserted, which may also generate an electric field spatially overlapping said magnetic field. The shunting device partially bypasses the magnetic flux of said circuit assembly and thus reduces the magnetic field to a desired value.

A fine-adjustable charged particle lens comprises a magnetic circuit assembly including permanent magnets, a yoke body, and a shunting device comprising a shunting component, and this assembly surrounds a beam passage extending along the longitudinal axis (cx). The shunting device is placed in the yoke body besides the permanent magnets and may be composed of several sector components, comprising different high magnetically permeable materials. The permanent magnet and the yoke body form a magnetic circuit having at least two gaps, in order to generate a magnetic field reaching inwards into the beam passage, into which a sleeve insert having electrostatic electrodes can be inserted, which may also generate an electric field spatially overlapping said magnetic field. The shunting device partially bypasses the magnetic flux of said circuit assembly and thus reduces the magnetic field to a desired value.

A charged particle beam system can include a vacuum chamber, a specimen holder for holding a specimen within the vacuum chamber, and a charged particle column. The charged particle column can include a charged particle source for producing a beam of charged particles along an optical axis and a magnetic immersion lens for focusing the beam of charged particles. The magnetic immersion lens can include a first lens pole disposed adjacent a first surface of the specimen, an excitation coil surrounding the first lens pole, and a counterpole disposed adjacent a second surface of the specimen, the counterpole including one or more magnets disposed on the counterpole.

A charged particle beam system can include a vacuum chamber, a specimen holder for holding a specimen within the vacuum chamber, and a charged particle column. The charged particle column can include a charged particle source for producing a beam of charged particles along an optical axis and a magnetic immersion lens for focusing the beam of charged particles. The magnetic immersion lens can include a first lens pole disposed adjacent a first surface of the specimen, an excitation coil surrounding the first lens pole, and a counterpole disposed adjacent a second surface of the specimen, the counterpole including one or more magnets disposed on the counterpole.

This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

This invention provides a charged particle source, which comprises an emitter and means fo generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.

This invention provides a charged particle source, which comprises an emitter and means for generating a magnetic field distribution. The magnetic field distribution is minimum, about zero, or preferred zero at the tip of the emitter, and along the optical axis is maximum away from the tip immediately. In a preferred embodiment, the magnetic field distribution is provided by dual magnetic lens which provides an anti-symmetric magnetic field at the tip, such that magnetic field at the tip is zero.