A GaAs pixel detector for mammography: project development and transfer to technology

A GaAs pixel detector for mammography has been designed and tested. A front-end chip has been designed and produced (MEDIPIX), able to read out 64×64 channels in single photon counting mode, each one 170 μm wide. On the chip, each channel is provided with a 24 μm diameter region which is the space needed to “bump-bond” the read-out chip to the detector. This GaAs detector is able to perform a measurement of low-contrast details, with minimum contrast lower (up to a factor two) than typically detected by standard mammographic film+screen systems, in the same conditions of clinical routine. This should allow for an earlier diagnosis of breast tumor masses.