A CdTe gamma-ray spectrometer with imaging capabilities for astrophysics: Monte Carlo simulation results

Abstract

One of the critical design constraints for satellite-borne gamma-ray astronomy telescopes incorporating solid-state (mainly Ge) detectors has been the problem of keeping the detection plane at a very low temperature. This problem should be alleviated by the considerable progress being made in the technology of room temperature devices such as CdTe detectors. Furthermore, a new geometrical arrangement in the design of these particular detectors allows the use of small devices (μ-detectors) with high detection efficiency and good spectroscopic performance (E/δE ∼ 100). These μ-detectors can be mosaiced in order to form a large area position sensitive detector (PSD) with fine spatial resolution (about a few millimeters). Such a PSD could be coupled with a coded aperture to realise a telescope for use in high energy astronomy (0.05–5 MeV). Herein we give preliminary results from a Monte Carlo simulation of such a PSD concerning the detection efficiency and spatial resolution as a function of photon energy and incident angle. The results suggest that CdTe is a promising new detection medium for use in high energy astronomy.