Multi-mass filter with electric field variations
AssigneeArchimedes Technology Group, Inc.
InventorsRobert L. Miller, Tihiro Ohkawa, Richard L. Freeman
Life of this patent
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Abstract
A multi-mass filter for separating particles of a multi-species plasma includes a chamber, which defines an axis. A radial electric field is crossed with a magnetic field (E×B) to move the particles of different mass (M1, M2 and M3) on respective trajectories into respective first, second and third regions. Specifically, particles M1 are confined in the first region, while both particles M3 and M2 are ejected from the first region into the second region and only the particles M3 are ejected from the second region into the third region.
Claims17
A multi-mass filter for separating particles according to mass which comprises:
- a chamber having a chamber wall;
- a means for providing a multi-species plasma including particles of relatively low mass-charge ratio (M1), particles of intermediate mass-charge ratio (M2), and particles of relatively high mass-charge ratio (M3), said multi-species plasma having a density in said chamber less than a predetermined collisional density;
- a means for establishing an electric field crossed with a magnetic field (E×B) in said chamber to move said particles (M1, M2 and M3) on respective trajectories in said chamber;
- a first means for configuring (E×B) to confine said particles M1 in a first region of said chamber;
- and
- a second means for configuring (E×B) to confine said particles M2 to a second region of said chamber and to allow said particles M3 to collide with said chamber wall for collection therefrom.
A multi-mass filter for separating particles according to their mass which comprises:
- a chamber defining an axis and having a chamber wall;
- a means for providing a multi-species plasma in said chamber, said multi-species plasma including particles of relatively low mass-charge ratio (M1), particles of intermediate mass-charge ratio (M2), and particles of relatively high mass-charge ratio (M3), said multi-species plasma having a density in said chamber less than a predetermined collisional density;
- a means for generating a magnetic field (B) in said chamber wherein said magnetic field (B) is substantially constant along said axis and is oriented substantially parallel thereto;
- and
- an electrical means for creating a radial distribution for electrical fields (E1/E2) having a positive voltage Vctr along said axis with said electric field (E1) increasing at a first rate radially outward between said axis and a radial distance a2 (r2) to define a first region therebetween and establish a cut-off mass Mc2=er22B2/(8*(Vctr−V2)), wherein “e” represents a positive ion charge, with M3 and M2 being greater than Mc2 to shift particles M3 and M2 from said first region into a second region, and with said electrical field (E2) increasing radially outward between said radial distance a2 (r2) and a radial distance a3 (r3) at a second rate to establish a cut-off mass Mc3=e(r32−r22)B2/(8*V2) with M3 being greater than Mc3 to shift particles M3 from said second region into a third region for collision with said chamber wall and for collection therefrom.
A multi-mass filter for separating particles according to mass which comprises:
- a chamber;
- a means for providing a multi-species plasma in said chamber, said multi-species plasma including particles of relatively low mass-charge ratio (M1), particles of intermediate mass-charge ratio (M2), and particles of relatively high mass-charge ratio (M3), said multi-species plasma having a density in said chamber less than a predetermined collisional density;
- and
- a means for configuring a radial distribution for an electric field (E), in said chamber in combination with an axial magnetic field (B), to provide E×B forces on said particles to establish respective first trajectories for each of said particles (M1), second trajectories for each of said particles (M2), and third trajectories for each of said particles (M3), and to respectively direct each said particle (M1) on its said first trajectory from said chamber into a first region, to direct each said particle (M2) on its said second trajectory from said chamber into a second region, and to direct each said particle (M3) on its said third trajectory from said chamber into a third region to separate said particles (M1, M2 and M3) according to mass-charge ratio.
Dependencies are inferred from the claim text.