A Radio Frequency Helical Deflector for keV Electrons

TL;DR

This paper introduces a radio frequency helical deflector for keV electrons that enables precise circular sweeps and timing measurements by converting electron time dependence into spatial position using a resonant circuit.

Contribution

It presents a novel helical deflector design with high Q resonant electrodes, capable of precise electron deflections in the 500-1000 MHz range, adjustable for electron velocity.

Findings

Achieves deflection sensitivity of about 1 mm per volt at resonance.

Resonant circuit with quality factor Q > 100 enhances performance.

Enables precise timing and spatial control of keV electrons.

Abstract

This paper describes a helical deflector to perform circular sweeps of keV electrons by means of radio frequency fields in a frequency range 500-1000 MHz. By converting the time dependence of incident electrons to a hit position dependence on a circle, this device can potentially achieve extremely precise timing. The system can be adjusted to the velocity of the electrons to exclude the reduction of deflection sensitivity due to finite transit time effects. The deflection electrodes form a resonant circuit, with quality factor Q in excess of 100, and at resonance the sensitivity of the deflection system is around 1~mm per V of applied RF input.