A Photon Imaging Detector Model with High Resolution and High Counting Rate

Abstract

A cross strip (XS) anode detector is a photon-counting imaging detector with high spatial resolution. However, due to the Poisson distribution characteristics of the photons emitted by the target, photons with a small time interval will cause signal superposition and resolution degradation. This is particularly significant at a high photon count rate. The key link that restricts the counting rate of the XS detector is the electronic system. In this paper, we propose a new electronic signal processing system scheme using a digital trapezoidal shaping filter instead of a traditional Gaussian shaping filter, which enables the detector to maintain a high resolution at high count rates. In order to verify the feasibility of the scheme, the relationship between shaping errors and shaping parameters is studied. Furthermore, the relationship between spatial resolution and photon-counting rate at different noise levels is revealed by numerical simulation. The results show that the detector can achieve a spatial resolution of <50 μm at a photon count rate of >6 MHz for 1000 e RMS noise.