Ultraviolet stimulated electron source for use with low energy plasma instrument calibration

TL;DR

This paper presents a compact, UV-stimulated electron source capable of producing a uniform, monoenergetic electron beam with precise energy and spatial control, suitable for calibration of low energy plasma instruments.

Contribution

It introduces a novel UV-LED illuminated metal cathode electron source with high uniformity, adjustable energy, and low divergence for plasma instrument calibration.

Findings

Electron beam energy spread <10 eV

Uniformity variation 15% over 1 cm^2

Beam intensity up to 10^9 electrons/cm^2s

Abstract

We have developed and demonstrated a versatile, compact electron source that can produce a monoenergetic electron beam up to 50 mm diameter from 0.1 to 30 keV with an energy spread of <10 eV. By illuminating a metal cathode plate with a single near ultraviolet (UV) light emitting diode (LED), a spatially uniform electron beam with 15% variation over 1 cm2 can be generated. A uniform electric field in front of the cathode surface accelerates the electrons into a beam with an angular divergence of <1 degree at 1 keV. The beam intensity can be controlled from 10^9 electrons/cm2s.