Design Considerations for the Next-Generation MAPMT-Based Monolithic Scintillation Camera.

Multi-anode photomultiplier tubes (MAPMTs) offer high spatial resolution with their small size anodes that may range from 64 to 1024 in number per tube. In order to increase detector size, MAPMT modules can be arranged in arrays and combined in a single modular scintillation camera. However, then the large number of channels that require amplification and digitization become practically not feasible unless signals are combined or reduced in some manner. Conventional approaches use resistive charge division readouts with a centroid algorithm (or a variant of it) for simplicity in the electronic circuitry implementation and fast execution. However, coupling signals from many anodes may cause significant information loss and limit achievable resolution. In this study, a new approach for optimizing readout-electronics design for MAPMTs based on an analysis of information content in the signals is presented. An adaptive read-out scheme to be used with maximum-likelihood estimation methods is proposed. This scheme achieves precision in estimating event parameters that is close to what is achieved by retaining all signals.