Response of HR-GaAs:Cr sensors to subnanosecond X- and β-ray pulses

Currently, semiconductors with high atomic number Z arouse strong interest in construction of X-ray sensors. One of the most prospective materials are presented by elements from the group A(III)B(V). Gallium arsenide compensated with chromium (HR-GaAs:Cr) is one of these materials and exhibits unique characteristics. The sensors based on HR-GaAs:Cr demonstrate high absorption efficiency. The response of HR-GaAs:Cr sensors to subnanosecond X- and beta-ray pulses of 28 divided by 52 keV from an accelerator of runaway electrons are described in this research. The samples have symmetric metal-semiconductor-metal structure. The active area of the samples was 0.09 cm(2) and the thickness of sensitive layer was 145 divided by 500 mu m. Experimental characteristics of pulses were compared with theoretical estimations. An optimal thickness of sensitive layer of HR-GaAs:Cr sensors was determined, which allowed us to obtain the minimal possible value of output pulse duration approximate to 1 ns.