An ion separator includes a plasma source for generating a multi-species plasma having ions of heavy mass (M.sub.2) and light mass (M.sub.1). Also included is an accelerator for accelerating these ions to a common velocity (v.sub.o) before they are injected into a hollow chamber. For this invention, the chamber can be configured as a toroid or a cylinder confining a curved path which generates a mass proportional drift velocity (u.sub.d) for each ion as it travels along the path. Consequently, ions will collide with the chamber wall, in sequence, according to their mass. This will be at predetermined arc lengths (L) along the path in the chamber. Specifically, ions of heavy mass (M.sub.2) will collide with the chamber wall before ions of light mass (M.sub.1). The ions can then be subsequently removed from the chamber wall. For one embodiment, the geometry of the chamber is established as a helix having a pitch angle which captures only heavy mass ions (M.sub.2) and allows ions of light mass (M.sub.1) to completely transit through the chamber.
This application is a continuation-in-part of application Ser. No. 08/970,548, filed Nov. 14, 1997, now U.S. Pat. No. 5,939,029. The contents of application Ser. No. 08/970,548 are incorporated herein by reference.
A device and method for selectively establishing predetermined orbits, relative to an axis, for ions of a first mass/charge ratio (m.sub.1), requires crossing an electric field with a substantially uniform magnetic field (E.times.B). The magnetic field is oriented along the axis and the electric field has both a d.c. voltage component (.gradient..PHI..sub.0) and an a.c. voltage component (.gradient..PHI..sub.1). In operation, voltage .PHI..sub.0 is fixed to place the ions m.sub.1 on confined orbits around the axis when .PHI..sub.1 is zero. On the other hand, when .PHI..sub.1 is tuned to a predetermined value, the ions m.sub.1 are ejected away from the axis. With E.times.B established in a chamber, the ions m.sub.1 will pass through the chamber when on confined orbits (.PHI..sub.1 =0), and they will be ejected into the wall of the chamber when on unconfined orbits (.PHI..sub.1 =predetermined value).
A filter and a method for separating ions in a partially ionized plasma according to their mass includes a chamber with crossed electric and magnetic fields established therein. A feed, including metal atoms having ionization potentials in a low range, and gas atoms having an ionization potential in a high range, is introduced into the chamber. An electron temperature below the low range is generated to partially ionize the feed by dissociating the metal atoms from the gas atoms, and by ionizing the metal atoms into light and heavy ions according to their mass to charge ratio. The light and heavy ions are then influenced by the crossed electric and magnetic fields to separate the light ions from the heavy ions.
A device for separating high mass to charge particles (M.sub.1) from low mass to charge particles (M.sub.2) in a plasma includes a cylindrical wall that surrounds a chamber and defines an axis. Rectangular shaped coils are mounted on the wall to establish a magnetic field, B.sub.0, in the chamber that is aligned substantially perpendicular to the axis and which rotates about the axis. Circularly shaped coils are provided to generate a time-constant, axially aligned magnetic field, B.sub.z, in the chamber. Passive, ring-shaped electrodes are positioned at the ends of the wall and connected to resistors which are then grounded. The rotating magnetic field, B.sub.0, rotates the plasma in the axially aligned magnetic field, B.sub.z, which in turn, induces a radially oriented electric field, E.sub.r, in the chamber. The crossed fields (i.e. E.sub.r.times.B.sub.z) cause the particles, M.sub.1, to strike the wall while the particles, M.sub.2, transit through the chamber.
A device for separating particles according to their respective masses includes a substantially cylindrical wall of inner radius, "R.sub.wall ", that surrounds a chamber and defines a longitudinal axis. A multi-species plasma having relatively cold ions is initiated at a first end of the chamber within a relatively small radius, "r.sub.source ", from the longitudinal axis. A hollow cylinder having an outer radius, "R.sub.outer ", is positioned at the second end of the chamber and centered on the axis. Cross electric and magnetic fields (E.times.B) are established in the chamber that are configured to send ions of relatively high mass on trajectories having a radial apogee, r.sub.apogee, that is greater than the cylinder's outer radius (r>R.sub.outer). After reaching apogee, these ions lose energy and strike the cylinder where they are collected. Low mass ions are placed on small radius helical trajectories and pass through the hollow cylinder.
A device for separating the constituents of a multi-constituent material includes a substantially cylindrical plasma chamber and two, axially opposed plasma injectors. The injectors convert the multi-constituent material into a multi-species plasma and inject the multi-species plasma into a core portion of the plasma chamber. Ions in the plasma diffuse from the core portion to an annular volume within the chamber where the ions are separated according to their respective mass to charge ratios. To effect separation, electrodes and coils are provided to establish crossed electric and magnetic fields in the annular volume. With the crossed electric and magnetic fields, low-mass ions in the annular volume are placed on small orbit trajectories and drift axially for capture at the ends of the plasma chamber. High-mass ions in the annular volume are placed on large orbit trajectories for capture at the cylindrical wall of the chamber.
