GaAs pixel radiation detector as an autoradiography tool for genetic studies

We present an autoradiography tool to be used mainly for genetic studies. I t performs a quantitative analysis of radioactivity and can follow a dynami c process. We designed several applications, in particular one aimed at det ecting hybridization of radio-labeled DNA fragments with known DNA-probes d eposited on a micro-array. The technique is based on GaAs pixel array detec tor and low threshold, large dynamic range and good sensitivity integrated electronics developed for medical applications, suitable to detect markers (gamma or beta) such as C-14, S-35, P-33, P-32, I-125, even at very low act ivities. A Monte Carlo simulation of beta(-) detection in GaAs is presented here in order to study the spatial resolution characteristics of such a sy stem. For several biological applications, the electronics is required to p erform at high temperatures (from 37 degrees to 68 degrees): we present her e studies of noise and minimum threshold as a function of the temperature. (C) 1999 Elsevier Science B.V. All rights reserved.