High resolution CdTe detectors for the next-generation multi-Compton gamma-ray telescope

Abstract

A multi-Compton gamma-ray telescope based on high resolution semiconductor materials (Semiconductor Multi-Compton Telescope (SMCT) or Advanced Compton Telescope (ACT)) is a promising approach to achieve high sensitivity for gamma-rays with energies from several hundred keV up to several MeV. A SMCT utilizing several tens of layers of thin CdTe (Cadmium Telluride) detector is an attractive concept to obtain higher detection efficiency in comparison with Si-based SMCT. Recently we have developed high energy-resolution CdTe diode detectors. A large-area detector with dimensions of 2.15 × 2.15 cm² with a thickness of 0.5mm shows an energy resolution of better than 3 keV (FWHM) at 60 keV. In order to extend the application of CdTe diodes to the detection of MeV gamma-rays, we have constructed a stacked detector consisting of 40 layers of large CdTe diodes. Here we report the recent progress on the high-resolution CdTe diode and describe the conceptual design of new Multi-Compton Gamma-ray telescopes based on Monte Carlo simulation. An idea of active pair production telescope is briefly described.