Advances In Microchannel Plate Detectors

Abstract

A number of current developments in microchannel plate (MCP) manufacturing technology promise significant advances in detector performance both for X-ray astronomy and for other fields. These include the production of: (i) MCPs made from radioisotope-free ('low-noe') lead glasses (ii) low resistance MCPs for high count rate applications (iii) large area (-100 cm ) channel plates and (iv) MCPs with small (2-6 micron) channel diameters. In this paper, we present measurements made on prototype low noise, low resistance no MA.) MCPs fabricated by Galileo Electro-Optics. These MCPs exhibit a limiting dark noise count rate ten times lower than2 that of the same manufacturer's standard plates. Contributions to the residual count rate (-0.07 cm s ) from cosmic ray interactions, field emission, trace radioisotope contamination and pressure effects are discussed. Thermal modelling of the new Galileo MCPs is correlated with their observed noise and count rate characteristics. Results of an accelerated lifetest are described. Incidental noise images are presented from the large area detector developed at Leicester to evaluate MCPs for the AXAF High Resolution Camera (HRC). Calculations of induced radioactivity in satellite-borne MCP detectors and their associated photocathodes are described. A theoretical model is used to predict the gain and temporal response of MCPs with reduced pore sizes.