Mass analyzer apparatus and systems operative for focusing ribbon ion beams and for separating desired ion species from unwanted ion species in ribbon ion beams

An assembly for focusing a traveling charged particle beam which will transversely pass through it, the beam's travel direction being substantially the z-direction in a Cartesian coordinate system, said assembly comprising:

• a matched pair of oppositely disposed and aligned pre-formed focusing articles set spatially apart from each other at a fixed gap distance, and wherein the traveling charged particle beam will transversely pass in the z-direction through the spatial volume of said fixed gap distance between said matched pair of oppositely disposed articles,
• wherein each said article of said matched pair comprises
• a substantially E-shaped block mounting formed of ferromagnetic material and wherein the exposed block face presents at least three discrete and spatially distanced parallel raised ridges and at least two interposed and spatially distanced parallel recessed channels, and wherein said E-shaped block mounting
• (α) dimensionally extends in the x-axis direction for a distance greater than the x-axis size of the traveling charged particle beam which will pass near a z-x plane over it, and
• (β) said three spatially distanced parallel raised ridges and said two interposed and spatially distanced parallel recessed channels lie perpendicular to the direction of travel of the charged particle beam, and
• magnetic field generating means which are transversely fitted into the structure of and are disposed in an x-z plane of said E-shaped block mounting, the magnetic field generated by said means extending perpendicularly in the y-direction from the exposed block face of said E-shaped block mounting;
• and
• means for directing a traveling charged particle beam to pass transversely through said fixed gap distance existing between said exposed face of each E-shaped block mounting in said oppositely disposed article pair.

An assembly for focusing and separating desired ions of a certain narrow range of magnetic rigidity and rejecting other unwanted ions then present in at least one traveling charged particle beam, the beam's travel direction being substantially the z-direction in a Cartesian coordinate system, said assembly comprising:

• (α) a vacuum chamber enclosing a travel passageway of known spatial volume through which a charged particle beam will pass;
• (β) a matched pair of oppositely disposed and aligned pre-formed articles positioned within the spatial volume of said vacuum chamber, said matched pair of articles being set spatially apart from each other at a fixed gap distance, and wherein the traveling charged particle beam will transversely pass in the z-direction through the spatial volume of said fixed gap distance between said matched pair of oppositely disposed articles, and wherein each said article of said matched pair comprises
• a substantially E-shaped block mounting formed of ferromagnetic material and wherein the exposed block face presents at least three discrete and spatially distanced parallel raised ridges and at least two interposed and spatially distanced parallel recessed channels, and wherein said E-shaped block mounting
• (i) dimensionally extends in the x-axis direction for a distance greater than the x-axis size of the traveling charged particle beam which will pass near a z-x plane over it, and
• (ii) said three spatially distanced parallel raised ridges and said two interposed and spatially distanced parallel recessed channels lie perpendicular to the direction of travel of the charged particle beam, and
• magnetic field generating means which are transversely fitted into the structure of and are disposed in an x-z plane of said E-shaped block mounting, the magnetic field generated by said means extending perpendicularly in the y-direction from the exposed face of said E-shaped block mounting;
• (γ) means for directing a traveling charged particle beam to pass transversely through said fixed gap distance existing between said exposed face of each E-shaped block mounting in said oppositely disposed article pair.
• (δ) at least one beam stop centrally located within the spatial volume of said fixed gap distance existing between said pair of oppositely disposed articles such that at least one off-center passage lane is formed within said gap distance, whereby said beam stop prevents straight-through travel of the charged particle beam, but allows for off-center lane passage of the charged particle beam through said off-center passage lane existing between said beam stop and said pair of oppositely disposed articles;
• and
• (ε) a preformed aperture-containing barrier which is positioned downstream from and is centered on the mid-plane of said pair of oppositely disposed and aligned pre-formed focusing articles, said aperture-containing barrier allowing those portions of the traveling charged particle beam which are routed through said off-center passage lane to be deflected through a limited range of angles;
• whereby a focusing of ions and a separation of desired ions having a predetermined range of mass and energy attributes is made from other unwanted ions present in the charged particle beam.

A method of focusing a traveling ribbon-shaped ion beam comprising the steps of:

• generating a multi-zone symmetrical magnetic field via a matched pair of oppositely disposed and aligned pre-formed articles set spatially apart from each other at a fixed gap distance, said pair of oppositely disposed articles being able to generate a symmetrical magnetic field which extends perpendicularly across said fixed gap distance, wherein
• (i) the orientation of a first zone in the generated magnetic field is in the direction of travel of the ions in the beam, and
• (ii) the orientation of a second zone in the generated magnetic field in is in a direction opposite to that of said first zone of magnetic field;
• and
• causing the traveling ribbon-shaped ion beam to transversely pass through said generated multi-zone symmetrical magnetic field existing within the spatial volume of said fixed gap distance between said matched pair of oppositely disposed articles.

A method for concurrently generating a mass-analyzed pair of discrete ion beams wherein each beam contains a desired ion species and unwanted ion species, said method comprising the steps of:

• providing an ion source having two parallel extraction slits from which a pair of discrete ion beams that are almost parallel in trajectory but diverge from each other at a small angle are extracted, each of said extracted ion beams of said pair containing a desired ion species and at least one unwanted species of ion;
• passing said pair of extracted ion beams through a focusing apparatus having chromatic aberration, wherein one of said beams passes on each side of a symmetry plane of said focusing apparatus;
• adjusting the focusing strength of said focusing apparatus to direct the trajectories of both said beams concurrently through a single aperture-containing barrier disposed on the symmetry plane downstream from said focusing apparatus;
• providing at least one beam blocking stop to intercept those ions which stray too near the symmetry plane of said focusing apparatus,
• providing at least one beam blocking stop to intercept any ions which stray too far from the symmetry plane of said focusing apparatus;
• and
• causing a separation of a desired ion species from unwanted species of ions in said pair of traveling ion beams wherein said separation of ion species is made on the basis of at least one physical attribute selected from the group consisting of ion mass differences, ion charge differences, beam energy differences, and magnetic rigidity differences.