Novel approach to use the Kelvin Probe method ex-situ for measuring the electron emission yield of insulator materials subjected to electron irradiation

Abstract

Measuring the total electron emission yield of dielectric materials remains a challenging task. Indeed, the charge induced by irradiation and electron emission disturbs the measurement. It is therefore important to quantify this charge during the measurement. Using a Kelvin probe allows both the emission yield and the induced charge to be measured. However, this method requires the probe to be placed inside the vacuum chamber, which is often complicated or even impossible. We propose a complete redesign of this method to overcome this issue. A capacitive coupling now allows the potential probe to be placed outside the chamber, in ambient atmosphere. Beyond this major simplification in implementation, we have also introduced several improvements that simplify the measurement protocol and reduce the overall measurement time. The new method was first validated on a metallic sample (Cu), and subsequently applied to a polymer (Kapton).