New tilted-poles Wien filter with enhanced performance

Abstract

The Wien filter is an E×B deflecting analyzer with the electrostatic field perpendicular to the magnetostatic field. The twofold functions of the Wien filter are as an energy analyzer as well as a mass analyzer. It has very high resolution for paraxial charged-particle beams with V=E/B, the Wien velocity. Two Wien filters, a tilted-poles Wien filter, and a classical parallel-rectangular-poles Wien filter were built and tested for electrons up to 3.5 keV and protons beams of 200 eV. (The tilted-poles Wien filter is a new diagnostic developed by the authors.) The performance of the two is compared, and the tilted-poles Wien filter has superior resolution to the classical Wien filter. Both Wien filters appear to have features useful for high-temperature plasma diagnostics, including simultaneous measurement of energy and mass spectra, and high resolution.