Design and Optimization of an X-ray Detector Module for Air-Cargo Inspection

In this study, we developed an X-ray detector module (XDM) that includes two readout electronic units and a 64-channel data acquisition system for X-ray imaging systems. The readout electronic unit comprises eight X-ray sensor arrays (two CdWO4 scintillators and four Si-PIN photodiodes per detector array), 32 charge integrators, 32 sample-and-holds (S/H), 4 shift registers, and a buffer. The data acquisition system comprises line drivers and receivers, a multiplexer, an analog-to-digital converter, and a 32-kB static random-access memory. All the control signals for module operation are implemented in a field-programmable gate array. The module operates with a single 24 V DC supply and transfers each channel’s data to the host computer through an Ethernet port. We fabricated a 64-channel electronic module and evaluated its performance in terms of the relative offset and linearity. By connecting 14 XDMs, air-cargo container images were successfully acquired through X-ray irradiation at an energy of 6-MeV.