A Medipix2-based imaging system for digital mammography with silicon pixel detector

In this paper we present the first tests of a digital imaging system based on a silicon pixel detector bump-bonded to an integrated circuit operating in single photon counting mode. The X-rays sensor is a 300 μm thick silicon, 14 by 14 mm2, upon which a matrix of 256 × 256 pixels has been built. The read-out chip, named MEDIPIX2, has been developed at CERN within the MEDIPIX2 Collaboration and it is composed by a matrix of 256 × 256 cells, 55 × 55 μm2. The spatial resolution properties of the system have been assessed by measuring the square wave resolution function (SWRF) and first images of a standard mammographic phantom were acquired using a radiographic tube in the clinical irradiation condition