Thermodynamic investigation of an insulator irradiated by a low-energy electron beam

TL;DR

This study investigates how low-energy electron irradiation affects the thermodynamic surface properties of insulators, revealing a temperature-dependent charge response linked to charged particle gas dynamics.

Contribution

It introduces a thermodynamic approach to analyze surface charge oscillations induced by electron beam irradiation on insulators.

Findings

Surface potential oscillates with temperature changes.

Response amplitude decreases with lower frequency.

Charge modification driven by charged particle gas dynamics.

Abstract

The surface of an insulating material irradiated by a beam of low energy electrons charges positively if the yield of secondary electron is greater than unity. For such a dynamical equilibrium, the thermodynamic properties have been investigated by measuring the surface potential in response to a temperature oscillation of the material. It is shown that an oscillation amplitude of 0.4 K at 530 K induces an oscillation of the surface potential of about 0.5 volts. The frequency dependence indicates a monotonous decrease in the response with decreasing frequency, extrapolating to zero at zero frequency. We propose that this modification of the surface charge is driven by the temperature dependence of a gas of charged particles in equilibrium with the vacuum level.