Fig. 3: Auto-ponderomotive guiding of various species of charged particles.
From: Charged particle guiding and beam splitting with auto-ponderomotive potentials on a chip
a, b Detector images of unguided electron a and helium ion b beams with electrodes grounded (UDC = 0 V). c, d With charged electrodes (UDC = 410 V), both beams are guided and are measured at x = 5.9 mm (electrons) and x = 6.1 mm (He-ions), almost exactly at the expected position of x = 5.8 mm. The barely visible curl structure results from spiraling trajectories of off-centrally injected particles. The detector signal of helium ions is expected to be the vertically mirrored image of the electron signal, due to the opposite sign of their charge, which can just be discerned. e, g Guiding stability: normalized intensity of guided electrons e and helium ions g on the MCP detector. For each acceleration voltage UA, the applied electrode voltage UDC was scanned from 0 to 1 kV and the guiding signal of each scan was normalized to its maximum value. For comparison with electrodynamic traps, the corresponding driving frequency and AC power (impedance of 50 Ω) are given on the secondary axes (blue). Black lines corresponding to operation at q = 0.4 and q = 0.9 are drawn in e and g as a guide to the eye. Even though their masses differ by more than five orders of magnitude, guiding starts for all particles at q ≈ 0.4 and no guiding is observed for q values >0.9, perfectly matching our particle tracking results. Because not all kinetic energies were possible to realize due to the source, some regions are left white. f Magnified image of a part of e showing that electrons are guided for kinetic energies as low as 20 eV, which was the lowest energy we could achieve with our source.
