Development of CdTe imaging detectors for a Compton Telescope

Imaging arrays of thick CdTe detectors, with millimeter spatial resolution and better than 10 keV energy resolution at I MeV, are very promising for the calorimeter section of an Advanced Compton Telescope. Measurements with small CdTe detectors with Schottky contacts, and advances in fabrication technology, have led us to the design of an 8 x 8 pixel array, with 2 x 2 mm(2) pixel size. as a first prototype module for large arrays. The detectors are arranged with the electric field direction perpendicular to the incoming gamma-ray direction, allowing several centimeters deep arrays, with the minimum amount of passive material. With the development of the 8 x 8, 10 mm deep array, we aim to demonstrate the feasibility of the concept for gamma-ray imaging.