Estimation and control of the mean response of photomultiplier tubes

Abstract

A maximum-likelihood parameter-estimation method is developed that allows the mean of coarsely digitized data to be determined to far greater precision than that inherent in the digital quantization. The method is used to determine the mean responses of photomultiplier tubes in a medical scintillation camera. The mean responses as determined by the estimation scheme are applied to two tasks. The first is the development and construction of a feedback-control loop to stabilize photomultiplier tube responses. The second is a method to characterize the camera face for the construction of a look-up table of maximum a posteriori position estimates used in image acquisition. The implementation of the parameter-estimation algorithm, its applications in both the stabilization of photomultiplier tube response and image look-up table construction, and the analysis of photomultiplier tube statistics, are considered to be the major contributions of the work presented in this thesis. (Abstract shortened with permission of author.)