A digital x-ray detector applying hybrid detector technology based on indium metal bump- bonding techniques was evaluated at x-ray energies of about 19.5 keV. Silicon of about 1 mm thickness forms the actual detector, converting x-rays directly into electrons (rather than generating light and converting light to photo-electrons). Time-delay-integration increases the sensitivity. Linearity, modulation transfer function, and noise power spectrum were evaluated. The results demonstrate that the system is useful as scanning x-ray detector for digital mammography and can meet and even exceed the performance of the conventional film/screen system.