Low-cost XRD detector technology which scales to large FoV

We have developed a low-cost, scalable detector component technology for x-ray diffraction (XRD) using room-temperature direct-conversion compound semiconductor arrays. Our approach uses two-side, butt-able and stackable modules of cadmium telluride (CdTe) sensors with an edge illuminated geometry. Edge illumination can achieve rapid complete charge collection in a CdTe array when interconnected to custom application specific integrated circuits (ASICs). The modules are tileable in one dimension due to their two-side, butt-able and stackable qualities due to the integration of the ASICs and readout within the active area of the edge illuminated pixels to produce a two-dimensional (2D) field of view (FoV). Since individual panels can be tested before the construction of large 2D FoV detectors, the cost per area is constant. We show results from individual pixels, individual modules, and individual 2D XRD cameras with a FoV up to 6 cm by 6 cm. The cameras demonstrate an energy resolution of ~3 keV full width at half maximum (FWHM) at room temperature across the entire dynamic range from 30 keV to 160 keV with minimal tailing. Edge illumination can also allow a large thickness of the CdTe sensor to be in the incident direction, producing a large detective quantum efficiency (DQE) at high energies (up to 160 keV) without sacrificing charge collection efficiency. Low-cost cameras with large FoVs with sufficiently good energy resolution and DQE could allow XRD imaging to achieve high sensitivity and reduce scan times by reducing false alarms from transmission imaging systems.