The impact of active area geometry and electrophysical characteristics on X-ray sensitivity and spatial resolution of GaAs:Cr radiation sensors

The results of calculations and experimental studies of pulse height distribution, sensitivity and spatial resolution dependences on detector's contact area and electric field profiles in chromium compensated gallium arsenide (GaAs:Cr) radiation sensors are presented. Mathematical modeling of electric field distribution for various contact and active area sizes were made. It is shown that spatial resolution is determined not only by the mobility-lifetime product, but also by polarity of applied bias. Several methods were suggested to improve energy resolution of GaAs:Cr sensors.