Microsphere plate electron multiplier: measurements and modeling

Microsphere plates (MSPs), a new type of electron multiplier, consisting of sintered disks of glass beads, have recently become available from El-Mul Technologies Ltd. The principles of MSP operation are similar to those of microchannel plates (MCPs). This paper reports a survey of the gain, resistance, dark noise, count rate capability, charge abstraction lifetime, and image characteristics of a number of standard 33 mm diameter microsphere plates (of thickness 0.7 and 1.4 mm), operated both singly and as two-stage multipliers. We also describe a simple Monte-Carlo model of MSP operation, which enables us to estimate numerically a number of MSP characteristics, including (1) output pulse height distributions (PHDs), (2) output electron spatial and energy distributions, and (3) transit time distributions.