Author/Authors :
Da Via، نويسنده , , C. and Bates، نويسنده , , R. and Bertolucci، نويسنده , , E. and Bottigli، نويسنده , , U. and Campbell، نويسنده , , M. and Chesi، نويسنده , , E. and Conti، نويسنده , , M. and DʹAuria، نويسنده , , S. and DelPapa، نويسنده , , C. and Fantacci، نويسنده , , M.E. and Grossi، نويسنده , , G. and Heijne، نويسنده , , E. and Mancini، نويسنده , , E. and Middelkamp، نويسنده , , P. and Raine، نويسنده , , C. and Russo، نويسنده , , P. and OʹShea، نويسنده , , V. and Scharfetter، نويسنده , , L. and Smith، نويسنده , , K. and Snoeys، نويسنده , , W. and Stefanini، نويسنده , , A.، نويسنده ,
Abstract :
Gallium arsenide pixel detectors processed on a 200 μm Semi-Insulating (SI) Hitachi substrate were bump-bonded to the Omega3 electronics developed at CERN for high energy physics [1]. The pixel dimensions are 50 μm × 500 μm for a total of 2048 cells and an active area of ∼0.5 cm2. Our aim is to use this system for medical imaging. We report the results obtained after irradiation of the detector with different X-ray sources on phantoms with different contrasts. The system showed good sensitivity to X-rays from 241Am (60 keV) and 109Cd (22.1 keV). It is also sensitive to β− particles from 90Sr as well as from 32P which is used as a tracer for autoradiography applications. The inherent high absorption efficiency of GaAs associated with the self-triggering capabilities of the pixel readout system reduced considerably the acquisition time compared with traditional systems based on silicon or emulsions. The present configuration is not optimised for X-ray imaging. The reduction of the pixel dimensions to 200 μm × 200 μm together with the integration of a counter in the pixel electronics would make the detector competitive for applications like mammography or dental radiology. For certain applications in biochemistry, such as DNA sequencing, where good spatial resolution is required only in one direction, the present setup should allow the best spatial resolution available up to now with respect to other digital autoradiographic systems. DNA sequencing tests are now under way.
