Development and testing of a high resolution fan-beam gamma tomography system with a modular detector array

This work describes development and testing of a high resolution fan-beam gamma tomography system. This includes an array of 240 LYSO scintillators read out by silicon photomultipliers and a set of modular electronic readout boards for each eight detectors. Each readout channel consists of an amplifier and two counters with individually software-controllable energy thresholds, such that the difference in counts between the two thresholds corresponds to an energy region of interest. Control and readout of the modules is done remotely via Wi-Fi. While the system works with any gamma source, tomographic imaging tests were made using a nominally 15 Ci Ir-192 source. Reconstructed images demonstrate a spatial resolution of about 1 mm. The readout electronics module represents a flexible and scalable basis which can be used in computed tomography systems for a wide range of sources, geometries, and applications.