A GaAs pixel detector for mammography: project development and transfer totechnology

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 x 6 4 channels in single photon counting mode, each one 170 mu m wide. On the c hip, each channel is provided with a 24 mu m diameter region which is the s pace needed to "bump-bond" the read-out chip to the detector. This GaAs det ector is able to perform a measurement of low-contrast details, with minimu m contrast lower (up to a factor two) than typically detected by standard m ammographic film + screen systems, in the same conditions of clinical routi ne. This should allow for an earlier diagnosis of breast tumor masses. (C) 1998 Published by Elsevier Science B.V. All rights reserved.