Abstract: An apparatus for providing a magnetic field includes a magnet having a surface, and a structure disposed above the magnet surface. The structure includes a material of high magnetic permeability. The apparatus provides an interface between the material of high magnetic permeability and a material of low magnetic permeability. The apparatus may have two poles in magnetic communication with the magnet, the poles extending above the surface of the magnet, and the structure is disposed between the poles. The structure may have alternating regions of high magnetic permeability and low magnetic permeability. The apparatus alters the magnetic field of the magnet to reduce or remove a disorder in the magnetic field, and/or decrease the magnitude of the magnetic field, and/or induce a distortion in the magnetic field, and/or align or re-align the magnetic field, and/or orientate or re-orientate the magnetic field, and/or alter distribution or shape of the magnetic field.

Abstract: An apparatus for providing a magnetic field includes a magnet having a surface, and a structure disposed above the magnet surface. The structure includes a material of high magnetic permeability. The apparatus provides an interface between the material of high magnetic permeability and a material of low magnetic permeability. The apparatus may have two poles in magnetic communication with the magnet, the poles extending above the surface of the magnet, and the structure is disposed between the poles. The structure may have alternating regions of high magnetic permeability and low magnetic permeability. The apparatus alters the magnetic field of the magnet to reduce or remove a disorder in the magnetic field, and/or decrease the magnitude of the magnetic field, and/or induce a distortion in the magnetic field, and/or align or re-align the magnetic field, and/or orientate or re-orientate the magnetic field, and/or alter distribution or shape of the magnetic field.

Abstract: An electron multiplier detector includes cathode structure defining a plurality of spaced co-planar impact surface segments on which particles impact. These surface segments each have a finite probability of generating at least one electron for each impacting particle having predetermined characteristics. The detector further includes respective sets of electron multiplication dynode segments associated with the impact surface segments, the sets being arranged as substantially parallel arrays extending behind the impact surface segments, and respective means for generating electrostatic and magnetic fields in a space extending from the impact surface segments past the dynode segments, whereby respective streams of electrons cascade and multiply successively along the arrays of dynode segments. Collector structure is provided to receive and detect the streams of electrons downstream of the last dynode segments in the arrays.

Abstract: Electron focussing apparatus includes a cathode plate defining an impact surface on which particles impact, which surface has a finite probability of generating at least one electron for each impacting particle having predetermined characteristics. The apparatus also has an electron receiving element, and respective means for generating electrostatic and magnetic fields in a space extending from the impact surface to the electron receiving element. The means for generating the electrostatic and magnetic fields are configured whereby the E/B2 ratio adjacent the electron receiving element is smaller than adjacent the impact surface, whereby to decrease the radius of curvature of the electron trajectories adjacent the electron receiving element relative to adjacent the impact surface and to thereby focus the electron trajectories in at least one dimension.

Abstract: Electron focussing apparatus includes a cathode plate defining an impact surface on which particles impact, which surface has a finite probability of generating at least one electron for each impacting particle having predetermined characteristics. The apparatus also has an electron receiving element, and respective means for generating electrostatic and magnetic fields in a space extending from the impact surface to the electron receiving element. The means for generating the electrostatic and magnetic fields are configured whereby the E/B2 ratio adjacent the electron receiving element is smaller than adjacent the impact surface, whereby to decrease the radius of curvature of the electron trajectories adjacent the electron receiving element relative to adjacent the impact surface and to thereby focus the electron trajectories in at least one dimension.