A magnetically microfocused electron emission source apparatus is disclosed. The apparatus may include a magnetic emitter unit, wherein the magnetic emitter unit comprises an emitter. Further, the magnetic emitter unit may include one or more magnetic portions formed from one or more magnetic materials, wherein the one or more magnetic portions of the magnetic emitter unit are configured to generate a magnetic field proximate to a tip of the emitter of the magnetic emitter unit for enhancing focusing of the emitted electrons from the electron emitter.

A magnetically microfocused electron emission source apparatus is disclosed. The apparatus may include a magnetic emitter unit, wherein the magnetic emitter unit comprises an emitter. Further, the magnetic emitter unit may include one or more magnetic portions formed from one or more magnetic materials, wherein the one or more magnetic portions of the magnetic emitter unit are configured to generate a magnetic field proximate to a tip of the emitter of the magnetic emitter unit for enhancing focusing of the emitted electrons from the electron emitter.

Variable-focus solenoidal lenses for charged particle beams with integrated emittance filtering are disclosed. The emittance may be controlled via selection of collimating irises. The focal length may be changed by altering the spacing between two permanent ring magnets.

Variable-focus solenoidal lenses for charged particle beams with integrated emittance filtering are disclosed. The emittance may be controlled via selection of collimating irises. The focal length may be changed by altering the spacing between two permanent ring magnets.

A magnetically microfocused electron emission source apparatus is disclosed. The apparatus may include a magnetic emitter unit, wherein the magnetic emitter unit comprises an emitter. Further, the magnetic emitter unit may include one or more magnetic portions formed from one or more magnetic materials, wherein the one or more magnetic portions of the magnetic emitter unit are configured to generate a magnetic field proximate to a tip of the emitter of the magnetic emitter unit for enhancing focusing of the emitted electrons from the electron emitter.

The present invention provides a technique for constructing compact, high gradient magnetic lenses for charged particle beam focusing. Methods for adjusting the focusing strength of the lenses are provided, based on thermal control, mechanical motion of the magnetic chips within the yoke. The present invention is a method for designing and fabricating permanent magnet focusing elements that are compact, simple to construct, and having a large, adjustable focusing strength. Applications include beamlines for THz radiation sources, free electron lasers, wakefield accelerators and any other charged particle devices that require a compact beamline.