Development of Tiled Imaging CZT Detectors for Sensitive Wide-Field Hard X-Ray Surveys to EXIST

Abstract Motivated by the proposed EXIST mission, a “medium-class” space observatory to survey black holes and the Early Universe proposed to the 2010 NAS/NRC Astronomy and Astrophysics Decadal Survey, we have developed the first “large” area 256 cm 2 close-tiled (0.6 mm gaps) hard X-ray (20–600 keV) imaging detector employing pixelated (2.5 mm) CdZnTe (CZT) detectors, each 2×2×0.5 cm 3 . We summarize the design, development and operation of this detector array (8×8 CZTs) and its performance as the imager for a coded aperture telescope on a high altitude (40 km) balloon flight in October, 2009, as the ProtoEXIST 1 payload. We then outline our current development of a second-generation imager, ProtoEXIST 2, with 0.6 mm pixels on a 32×32 array on each CZT, and how it will lead to the ultimate imaging system needed for EXIST . Other applications of this technology will also be mentioned.