A new formula for secondary emission yield in the low voltage region: An improvement of Vaughan's expression

Abstract

Reducing the emission of secondary electrons from anode materials is critical to improved efficiency and increased performance in high power vacuum electronics for defense systems. The focus of this proposed effort is to leverage advances in materials technology, specifically thin films, to reduce secondary electron generation and outgassing from anode surfaces. By using advanced thin film deposition techniques, hybrid materials can be developed that provide the thermal and electrical conductivity required for operation, while reducing secondary electrons and desorption of gas species from the anode surface. Proposed solutions to these issues need to be robust, yet cost effective and applicable through available manufacturing processes. In this paper, we will introduce an improved mathematical expression for the secondary emission yield as a function of the impact voltage which is an extension of the formula first introduced by Vaughan [1]. Our expression gives a better fit to some of our experimental data of secondary emission yield versus impact voltage for polycrystalline Copper for which the maximum secondary emission yield is only slightly larger than unity.