A beam deflector includes a magnetic-flux-guiding structure which has an opening through which a beam axis extends, and at least two coils arranged at the magnetic-flux-guiding structure so that they produce a magnetic field B.sub.1 having lines passing through the two coils in succession, leave the magnetic-flux-guiding structure at a first location on a first side in relation to the beam axis, cross the beam axis at a second location which is arranged at a distance along the beam axis from the magnetic-flux-guiding structure, re-enter into the magnetic flux-guiding structure at a third location on a second side lying opposite the first side, and extend around the opening from the third location to the first location within the magnetic-flux-guiding structure.

By switching between a plurality of image transfer units based on a state of a stage and using the switched image transfer unit, traceability of stage movement and tolerance to communication failure can be improved. A first image transfer protocol is a protocol of which reliability is higher than reliability of a second image transfer protocol, and a switch unit may select a first image transfer unit in a case where it is determined that a state of a stage is a state in which the stage is stopping. A second image transfer unit is a protocol of which a transfer speed is higher than a transfer speed of the first image transfer protocol, and the switch unit may select the second image transfer unit in a case where it is determined that the state of the stage is a state in which the stage is moving.

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.

In an embodiment, a plasma processing system includes a vacuum chamber, a substrate holder configured to hold a substrate to be processed where the substrate holder is disposed in the vacuum chamber. The system further includes an electron source disposed above a peripheral region of the substrate holder, the electron source being configured to generate an electron beam towards the peripheral region of the substrate holder.

Adjustable resolution electron energy loss spectroscopy methods and apparatus are disclosed herein. An example method includes operating an electron microscope in a first state, the first state including operating a source of the electron microscope at a first temperature, obtaining, by the electron microscope, a first EELS spectrum of a sample at a first resolution, the first resolution based on the first temperature, operating the electron microscope in a second state, the second state including operating the source of the electron microscope at a second temperature, the second temperature different than the first temperature, and obtaining, by the electron microscope, a second EELS spectrum of the sample at a second resolution, the second resolution based on the second temperature, wherein the second resolution is different than the first resolution.

The present invention relates to a method for examining a beam of charged particles, including the following steps: producing persistent interactions of the beam with a sample at a plurality of positions of the sample relative to the beam and deriving at least one property of the beam by analyzing the spatial distribution of the persistent interactions at the plurality of positions.

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.

An electron source, e.g. for a free electron laser used for EUV lithography comprises: a cathode (203) configured to be connected to a negative potential (100, 101); a laser (110) configured to direct pulses of radiation onto the cathode so as to cause the cathode to emit bunches of electrons; an RF booster (180) connected to an RF source and configured to accelerate the bunches of electrons; and a timing corrector (303, 313, 400, 401) configured to correct the time of arrival of bunches of electrons at the RF booster relative to the RF voltage provided by the RF source. The timing corrector may comprise a correction electrode (303, 313) surrounding a path of the bunches of electrons from the cathode to the RF booster and a correction voltage source (400, 401) configured to apply a correction voltage to the correction electrode.

Adjustable resolution electron energy loss spectroscopy methods and apparatus are disclosed herein. An example method includes operating an electron microscope in a first state, the first state including operating a source of the electron microscope at a first temperature, obtaining, by the electron microscope, a first EELS spectrum of a sample at a first resolution, the first resolution based on the first temperature, operating the electron microscope in a second state, the second state including operating the source of the electron microscope at a second temperature, the second temperature different than the first temperature, and obtaining, by the electron microscope, a second EELS spectrum of the sample at a second resolution, the second resolution based on the second temperature, wherein the second resolution is different than the first resolution.

A system that generates short charged particle packets or pulses (e.g., electron packets) without requiring a fast-switching-laser source is described. This system may include a charged particle source that produces a stream of continuous charged particles to propagate along a charged particle path. The system also includes a charged particle deflector positioned in the charged particle path to deflect the stream of continuous charged particles to a set of directions different from the charged particle path. The system additionally includes a series of beam blockers located downstream from the charged particle deflector and spaced from one another in a linear configuration as a beam-blocker grating. This beam-blocker grating can interact with the deflected stream of charged particles and divide the stream of the charged particles into a set of short particle packets. In one embodiment, the charged particles are electrons. The beam blockers can be conductors.