Abstract

Dead-time effects of microchannel plates (MCPs) are due to the recharging time of the semiconducting inner wall of individual microchannels. To study the dependence of dead-time effects on the area of illumination, circular apertures of different size are imaged onto the curved-channel microchannel plate (C-MCP) using ultraviolet light (257.3 nm). It is found that an independent paralyzable counter (IPC) model, which assumes that individual microchannels of the C-MCP behave as independent paralyzable counters with a fixed dead time, agrees well with experimental results. Except for the case of a small illuminated area, the variance data as well as the mean agree well with theoretical predictions up to a certain level of illumination. However, above this level of illumination the response of C-MCP becomes highly saturated and the IPC model no longer gives good predictions. From this investigation we may conclude that the apparent coupling between microchannels observed in previous investigations¹ is largely due to the complex structure of the MCP assembly, at least in the operational sense, rather than due to the intrinsic property of the MCP.

© 1989 Optical Society of America