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.

An electron optical module for providing an off-axial electron beam with a tunable coma, according to the present disclosure includes a structure positioned downstream of an electron source and an electron lens assembly positioned between the structure and the electron source. The structure generates a decelerating electric field, and is positioned to prevent the passage of electrons along the optical axis of the electron lens assembly. The electron optical module further includes a micro-lens that is not positioned on the optical axis of the electron lens assembly and is configured to apply a lensing effect to an off-axial election beam. Aberrations applied to the off-axial electron beam by the micro-lens and the electron lens assembly combine so that a coma of the off-axial beam has a desired value in a downstream plane.

An electron optical module for providing an off-axial electron beam with a tunable coma, according to the present disclosure includes a structure positioned downstream of an electron source and an electron lens assembly positioned between the structure and the electron source. The structure generates a decelerating electric field, and is positioned to prevent the passage of electrons along the optical axis of the electron lens assembly. The electron optical module further includes a micro-lens that is not positioned on the optical axis of the electron lens assembly and is configured to apply a lensing effect to an off-axial election beam. Aberrations applied to the off-axial electron beam by the micro-lens and the electron lens assembly combine so that a coma of the off-axial beam has a desired value in a downstream plane.

A charged particle beam device is provided in which axis adjustment as a superimposing lens is facilitated by aligning an axis of an electrostatic lens resulting from a deceleration electric field with an axis of a magnetic field lens. The charged particle beam device includes: an electron source; an objective lens that focuses a probe electron beam from the electron source on a sample; a first beam tube and a second beam tube through each of which the probe electron beam passes; a deceleration electrode arranged between the first beam tube and a sample; a first voltage source that forms a deceleration electric field for the probe electron beam between the first beam tube and the deceleration electrode by applying a first potential to the first beam tube; and a first moving mechanism that moves a position of the first beam tube.

A charged particle beam device is provided in which axis adjustment as a superimposing lens is facilitated by aligning an axis of an electrostatic lens resulting from a deceleration electric field with an axis of a magnetic field lens. The charged particle beam device includes: an electron source; an objective lens that focuses a probe electron beam from the electron source on a sample; a first beam tube and a second beam tube through each of which the probe electron beam passes; a deceleration electrode arranged between the first beam tube and a sample; a first voltage source that forms a deceleration electric field for the probe electron beam between the first beam tube and the deceleration electrode by applying a first potential to the first beam tube; and a first moving mechanism that moves a position of the first beam tube.

Systems for reducing the generation of thermal magnetic field noise in optical elements of microscope systems, are disclosed. Example microscopy optical elements having reduced Johnson noise generation according to the present disclosure comprises an inner core composed of an electrically isolating material, and an outer coating composed of an electrically conductive material. The product of the thickness of the outer coating and the electrical conductivity is less than 0.01Ω.sup.−1. The outer coating causes a reduction in Johnson noise generated by the optical element of greater than 2×, 3×, or an order of magnitude or greater. In a specific example embodiment, the optical element is a corrector system having reduced Johnson noise generation. Such a corrector system comprises an outer magnetic multipole, and an inner electrostatic multipole. The inner electrostatic multipole comprises an inner core composed of an electrically isolating material and an outer coating composed of an electrically conductive material.

Systems for reducing the generation of thermal magnetic field noise in optical elements of microscope systems, are disclosed. Example microscopy optical elements having reduced Johnson noise generation according to the present disclosure comprises an inner core composed of an electrically isolating material, and an outer coating composed of an electrically conductive material. The product of the thickness of the outer coating and the electrical conductivity is less than 0.01Ω.sup.−1. The outer coating causes a reduction in Johnson noise generated by the optical element of greater than 2×, 3×, or an order of magnitude or greater. In a specific example embodiment, the optical element is a corrector system having reduced Johnson noise generation. Such a corrector system comprises an outer magnetic multipole, and an inner electrostatic multipole. The inner electrostatic multipole comprises an inner core composed of an electrically isolating material and an outer coating composed of an electrically conductive material.

The invention provides a charged particle beam device that prevents a leakage of an unnecessary magnetic field to a trajectory of a charged particle beam with which a sample is irradiated in a sample observation according to a boosting method. The charged particle beam device includes: a charged particle source configured to generate the charged particle beam with which the sample is irradiated; an object lens configured to generate the magnetic field for focusing the charged particle beam; and a boosting electrode that is provided inside the object lens and to which a voltage for accelerating the charged particle beam is applied. The boosting electrode is formed of a magnetic material.

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.