ALD-GCA-MCPs: lifetime performance

Abstract

Conventional PbO-based Microchannel Plates (MCPs) are known to experience large drops in gain as a function of extracted charge, with a particularly large drop known as a “burn-in” period that occurs in the first 1 C/cm2 of extracted charge. Incom has developed ALD-GCA-MCPs that use Atomic Layer Deposition (ALD) to coat Glass Capillary Arrays (GCAs) of a base glass in order to make MCPs. In this way, the electrical and mechanical properties of the MCPs are separated. One advantage of this is that Incom can make MCPs out of various types of glass, such as aluminosilicate, which is substantially free of alkalis that can migrate in the glass matrix and change the electrical properties of the MCPs. This process has enabled Incom, using their proprietary C14 glass, to make MCPs that have much longer device lifetimes. The goal of these experiments was to compare the lifetime performance of Incom MCPs to PbO MCPs, as well as to compare the performance of ALD-GCA-MCPs made out of two types of glass substrates: C14 glass and an alkali-containing C5 glass. The MCP made with C14 glass had a gain of 1E4 at 950 V after 300 C/cm2 extracted charge, and no spatial variations in gain out to at least 23 C/cm2. The MCPs made of C5 glass exhibited imaging defects after 3 C/cm2. The gain of the PbO MCP fell to 1E3 at 950 V after 110 C/cm2.