Hard X-ray and γ-ray detectors for the NeXT mission

When compared with X-ray astronomy, the gamma-ray astronomy, especially in the energy band from 10 keV to several MeV, is still immature and significant improvements should be done to obtain sensitivity comparable to that achieved in the energy band below 10 keV. In order to fill this "sensitivity gap", the NeXT (New X-ray Telescope) mission has been proposed as a successor of the Astro-E2 mission. The high-energy response of the super mirror will enable us to perform first sensitive imaging observation up to 80 keV. One idea for the focal plane detector is to combine a fully depleted X-ray imaging device (soft X-ray detector) and a pixelated CdTe (cadmium telluride) detector. In the soft gamma-ray band upto similar to1 MeV, a narrow field-of-view Compton gamma-ray telescope utilizing several tens of layers of thin Si or CdTe detector has been proposed to obtain much higher sensitivity than present instruments. (C) 2003 Elsevier B.V. All rights reserved.