An Electrostatic Torsion Lens for Charged-Particle Beam Shaping

The design presented in this paper is a electrostatic torsion lens intended for shaping ion beams for materials processing and instrument columns. Its operating principle is that a set of shaped electrostatic electrodes focuses a charged-particle beam, and an azimuthal electrode segment introduces a torsion-like twist to the focal field that is used to correct rotational aberration in the model. The design is computed from stated assumptions throughout; it is simulated, not measured, and no prototype results are reported. The headline result is a peak axial field of 400 kV/m, obtained with lens voltage of 8e+03 V, for a unit of mass 7.5 kg whose characteristic scale is a electrode gap of 0.02 m. A parameter sweep reported in the Results section shows how the output moves when the principal variable is changed, and the density of the working material, 2.7e+03 kg per cubic metre, sits about 54.6 orders of magnitude below the neutron-carrier density bound of 9.72e+57 kg per cubic metre, so the bound enters this design as a sizing ceiling and a margin statement rather than as an operating condition. The limitations are stated plainly: the lens consumes almost no power but its field quality is set by machining and alignment tolerances, which dominate the aberration budget in practice. Status: SIMULATED, NOT MEASURED.