Large area detector with the Medipix2 chip

After a successful FP5 application, Institut de Física d´Altes Energies (IFAE) embarked on making the first research mammography prototype detector with an active area of 5 cm × 5 cm. The results were very promising even though the project used the first version of the Medipix2 chip which had a significant temperature dependence. Later, IFAE and other partners of the FP5 project (DEAR-MAMA) founded X-Ray Imatek (XRI), a spin-off company, to continue with the research and development and to transform the concept into a viable industrial product. Over a period of 4 years, XRI has successfully build a full size mammography detector, based onMedipix2 (MXR2.0), which can produce an image with a size of up to 24 cm × 30 cm (standard in mammography), with a 55 μm pixel pitch and in photon counting mode, in just one second. This represents the largest detector of its kind accomplished to date and the largest detector ever made with Medipix2 chips. In this paper, we will describe this large area detector with an array of 11 × 9 Medipix2 chips in detail. Furthermore, we will present quantitative results comparing the detector performance with other digital detectors available in the market today.