A charged particle beam system includes a charged particle source, an extraction electrode, a suppressor electrode, a first variable voltage supply for biasing the extraction electrode with an extraction voltage and a second variable voltage supply for biasing the suppressor electrode with a suppressor voltage.

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.

This invention provides a charged particle source, which comprises an emitter and means of 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.

A particle source for producing a particle beam includes a particle emitter, a first plate, a first deflector and a second plate with an aperture. The first plate has a smaller aperture, downstream of which a first beam is formed, and a larger aperture, downstream of which a second beam is formed. A controller sets the deflection angle of the deflector so that in a first mode of operation that particles of the first beam pass through the aperture in the second plate and form the particle beam produced by the particle source. The controller sets the deflection angle so that in a second mode of operation that particles of the second beam pass through the aperture in the second plate and form the particle beam produced by the particle source.

A charged particle beam system includes a charged particle source, an extraction electrode, a suppressor electrode, a first variable voltage supply for biasing the extraction electrode with an extraction voltage and a second variable voltage supply for biasing the suppressor electrode with a suppressor voltage.

Provided is an electron gun that can have a setting to make it possible to irradiate a desired location on an irradiation target with an electron beam having a desired electron beam parameter by using only the component included in the electron gun. This object can be achieved by an electron gun including: a light source; a photocathode configured to generate releasable electrons in response to receiving light from the light source; an anode configured to generate an electric field between the photocathode and the anode, extract the releasable electrons by the generated electric field, and form an electron beam; and a control unit, and the control unit sets the number of emission times of the electron beam and sets an electron beam parameter for each emitting electron beam, or sets an emission duration of the electron beam and sets an electron beam parameter of an emitting electron beam in association with the emission duration.

Provided is a spin-polarized scanning electron microscope capable of improving an SNR of a detected signal. The spin-polarized scanning electron microscope includes: a spin-polarized electron source configured to irradiate a sample with a spin-polarized electron beam that is an electron beam whose spin is deflected in a specific direction; a scanning unit configured to scan the sample by deflecting the spin-polarized electron beam; a spin detector configured to detect a spin direction of an emitted electron that is an electron emitted from the sample scanned with the spin-polarized electron beam; and a control unit configured to control the spin direction to be detected by the spin detector based on the spin direction of the spin-polarized electron beam.

There is provided an electron microscope capable of producing good images by reducing contrast nonuniformity. The electron microscope (1) includes: an electron beam source (11) for producing an electron beam; a noise cancelling aperture (12) and an amplifier (42) for detecting a part of the electron beam; an effective value computing circuit (44) and a low frequency cut-off circuit (46) for extracting a DC component of an effective value of a detection signal emanating from the amplifier (42); an image detector (15) for detecting a signal produced in response to impingement of the beam on a sample (A); a preamplifier circuit (20) and an amplifier circuit (30); a divider circuit (54) for performing a division of the output signal (X) from the amplifier circuit (30) by the output signal (Y) from the amplifier circuit (42) and producing a quotient signal indicative of the result of the decision (X/Y); and a multiplier circuit (58) for multiplying the quotient signal by a signal (Z) extracted by the low frequency cut-off circuit (46).

When an emission current is changed, a decrease in brightness of an electron beam is prevented. An electron gun includes a cathode that emits thermoelectrons, a Wehnelt electrode that focuses the thermoelectrons, a control electrode that extracts the thermoelectrons from a distal end of said cathode, an anode that accelerates the thermoelectrons and irradiates a powder with the thermoelectrons as an electron beam, and an optimum condition collection controller that changes at least one of a bias voltage to be applied to the Wehnelt electrode and a control electrode voltage to be applied to the control electrode, and decides a combination of the bias voltage and the control electrode voltage at which the brightness of the electron beam reaches a peak.

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.