<title>The Vernier electronic readout: high resolution and image stability from a charge division readout for microchannel plates</title>

Abstract

Traditional charge division readouts used in microchannel plate detectors, such as the Wedge and Strip anode, while simple in operation, can suffer from positional nonlinearities and instability in absolute positioning. The cause of both effects is due to the ratio of charges collected on the individual electrodes not accurately representing the electrode geometry. This is primarily a result of redistribution of secondary electron is produced from the anode surface among the anode electrodes. The Vernier position readout is an analogue charge division electronic readout capable of exceptional position resolution and linearity. In order to exploit this performance to the full and produce a device with absolute position stability, the problem of second are electron redistribution has had to be overcome. We describe the result of a series of experiments to determine the physical processes producing charge redistribution in the Vernier anode. Understanding of the mechanisms underlying this phenomenon has allowed the modification of the detector, anode pattern design and data acquisition software to alleviate the limitations imposed. These modifications are also applicable to other anodes relying on analogue charge division and provide improvements in absolute positional stability and linearity. We present measurements of the imaging performance of a microchannel plate detector using the Vernier anode. These results show the high spatial resolution, improved positional stability and linearity that can be achievable by controlling secondary electron redistribution.