USE OF SILICON AND GAAS PIXEL DETECTORS FOR DIGITAL AUTORADIOGRAPHY

Solid state detectors made of Si (4.8x8 mm(2)) and GaAs (6.4x8 mm(2)) pixel matrices bump-bonded to the Omega2 and Omega3 electronic read-ou t systems, developed at CERN for H.E.P. experiments, have been used to obtain autoradiographic images of clusters of human epithelial cells and DNA fragments separated via electrophoresis, both labeled with P-3 2. The system has shown a good minimum detectable activity per unit ar ea of 2. 10(-4) cps mm(-2), and has proved linear for count rate in th e range 0.2-20 cpa, typical of autoradiography. The pixel dimensions a re 75x500 mu m(2) (Si-Omega2) and 50x500 mu m(2)(GaAs-Omega3), respect ively. We are able to clearly localize clusters of cells which have in corporated the radioactive tracer and DNA fragments on an electrophore tic gel on paper (blots).