Band gap mass filter with induced azimuthal electric field

摘要

A band gap mass filter for separating particles of mass (M₁) from particles of mass (M₂) in a multi-species plasma includes a chamber defining an axis. Coils around the chamber generate an axially aligned magnetic field defined (B=B₀+B₁ sin omegat), with an antenna generating the sinusoidal component (B₁ sin omegat) to induce an azimuthal electric field (E_theta) in the chamber. The resultant crossed electric and magnetic fields place particles M₂ on unconfined orbits for collection inside the chamber, and pass the particles M₁ through said chamber for separation from the particles M₂. Unconfined orbits for particles M₂ are determined according to an alpha-beta plot $\left(\mathrm{alpha}=\frac{{\mathrm{Omega}}_0^2+{\mathrm{Omega}}_1^2/2}{4{\mathrm{omega}}^2},\mathrm{and}\mathrm{beta}=\frac{{\mathrm{Omega}}_0{\mathrm{Omega}}_1}{8{\mathrm{omega}}^2}\right),$ where Omega₀ is the cyclotron frequency for particles with mass/charge ratio M, and wherein Omega₀=B₀/M and Omega₁=B₁/M.