X-ray imaging using a pixel GaAs detector

The electrical characteristics, charge collection efficiency and energy resolution of a GaAs detector made out of LEC material have been studied. A matrix of 36 square pixels was deposited on a 70 μm thick crystal; each pixel had an area of 200 × 200 μm2 with 20 μm spacing between adjacent pixels. This detector showed a charge collection efficiency uniformity among the pixels better than 88% when exposed to 60 keV photons, which ensures that a comfortable common threshold setting can be adopted without affecting the uniformity of the measurement. It was successful in recording (60 keV photon energy) the image of a wolframium slab, 100 μm thick.