The X-ray imager on AXO

DSRI has initiated a development program of CZT X-ray and gamma-ray detecto rs employing strip readout techniques. A dramatic improvement of the energy response was found operating the detectors as the so-called drift detector s. For the electronic readout, modern ASIC chips were investigated. Modular design and the low-power electronics will make large area detectors using the drift strip method feasible. The performance of a prototype CZT system will be presented and discussed. One such detector system has been proposed for future space missions: the X-Ray Imager (XRI) on the Atmospheric X-ray Observatory (AXO), which is a mission proposed to the Danish Small Satelli te Program and is dedicated to observations of X-ray generating processes i n the Earth's atmosphere. Of special interest will be simultaneous optical and X-ray observations of sprites that are flashes appearing directly above an active thunderstorm system. Additional objective is a detailed mapping of the auroral X-ray and optical emission. XRI comprises a coded mask and a 20 x 40cm(2) CZT detector array covering an energy range from 5 to 200keV. (C) 2001 Elsevier Science B.V. All rights reserved.