Spatial resolution and relative brightness of a microchannel plate detector system with P20 and P43 phosphor screens

摘要

A detector consisting of two biased microchannel plates and a P20 or P43 phosphor screen was illuminated with 500-eV electrons in order to characterize the size and amplitude of individual microchannel plate (MCP) firings as a function of phosphor-to-MCP distance d and voltage V_(acc). The P43 phosphor was significantly brighter (71%) than P20 at V_(acc) = 4250 V, and brighter but less so (4%) at V_(acc) = 8000 V. Events were Gaussian-shaped with full widths at half maximum of order 0.27 mm for V_(acc) = 4250 V and d = 2 mm. Widths decreased by 23% to 28% when V_(acc) was increased to 8000 V, and increased between 9 to 34% when doubling d, depending on V_(acc) and phosphor type.