Simulation of Alumina Nanopores as High Spatial Resolution Electron Multipliers

Abstract

An electron multiplier (EM) is a device that can multiply incident electrons in a process that involves electron bombardment of a secondary emissive material, resulting in a large shower of electrons. Several types of this device have been fabricated up to now for different purposes. The modern type of EMs is microchannel plates, which provide higher spatial resolution. In recent years, porous aluminum oxide membranes have been used to produce cheaper microchannel plates, carrying out etching process to widen the pore to several micrometers. The nanopores of these membranes have not been utilized as EMs because of their high aspect ratio, which causes attenuation of the secondary emission. No study has been conducted to evaluate the impact of geometrical characteristics of these nanopores on their electron multiplying performance. In this paper, finite element calculations along with Monte Carlo simulation were used to model the aluminum oxide nanopores as EMs. The obtained results showed that in an optimized condition, these nanopores can multiply the incident electrons. This investigation can help to develop an EM based on low-cost porous aluminum oxide membranes, which can provide a higher spatial resolution.