Lead Investigator: Dr. Alla Reznik
Semiconductor-based direct conversion detectors revolutionized radiation medical imaging since they allowed diagnostic capabilities not achievable with other detector approaches. The areas of highest impact are x-ray Radiography and Nuclear Medicine. Semiconductor detectors are also of a great significance to the field of x-ray Computed Tomography (CT) as they promise significant increase in intrinsic energy and spatial resolutions needed for better energy and material resolved CT imaging. Cadmium zinc telluride (CZT) is a material of choice for direct conversion CT detectors. Recently, CZT has been successfully employed in gamma cameras operating in CT-relevant energy range. However, for use in CT, CZT has to demonstrate electronic properties that satisfy the requirement of high x-ray fluxes typical for CT; this includes prevention of possible buildup of space charge and related dynamic polarization of a detector material. Therefore, the overall objective of this project is to investigate transport of photo-generated charge carriers in CZT (i.e, electron and hole mobilities and their temperatures and field dependencies) and to evaluate the potential of CZT photoconductor to be used in advanced CT detectors.