Low energy electron reflection from tungsten surfaces

TL;DR

This paper investigates quantum mechanical reflection of very low energy electrons from tungsten surfaces, highlighting theoretical considerations, experimental data, and the influence of magnetic fields relevant to fusion technology.

Contribution

It provides a review of the controversy, recommends reliable experimental datasets, and discusses magnetic suppression of electron reflection in fusion applications.

Findings

Quantum reflection dominates at very low energies.

Reliable experimental datasets are identified.

Magnetic fields can suppress electron reflection.

Abstract

The incidence of very low energy electrons on metal surfaces is mainly dictated by the phenomenon of quantum mechanical reflection at the metal interface. Low energy electron reflection is insignificant in higher energy regimes, where the more familiar secondary electron emission and electron backscattering processes are the dominant features of the electron-metal interaction. It is a highly controversial subject that has mostly emerged during the last years. In this brief note we examine the source of the controversy, present some basic theoretical considerations, recommend a dataset of reliable experimental results for the reflection of low energy electrons from tungsten surfaces and discuss the suppression of reflected electrons by external magnetic fields in the light of applications in fusion devices.