Integration of front-end electronics with GaAs pixel detectors: Experimental and feasibility analysis

This work aims to study the feasibility of the integration, on the same chi p, of GaAs pixel detectors and front-end electronics employing GaAs metal s emiconductor FET's (MESFET's) or high electron mobility transistors (HEMT's ), The interest of fully integrated GaAs systems lies in X and gamma-ray sp ectroscopy and imaging for scientific, industrial, and medical applications , The system design criteria and the prediction of the performance have bee n derived on the basis of recent experimental results on semi-insulating Ga As pixel detectors. Measurements of the relevant parameters of GaAs FET's s uitable for the stringent requirements of a spectroscopy-grade front-end am plifier are analyzed. It is shown that an optimized GaAs integrated system can reach an electronic noise level below 100 electrons rms (<1 keV FWHM) e ven at room temperature. Some open problems regarding the detector-electron ics integration are highlighted and discussed.