Response of CdZnTe Detectors on the Swift Burst Alert Telescope

S w i f t (Gehrels, 2000) is the Gamma Ray Bursts (GRBs) explorer, that is scheduled for launch in 2004. The Swift's major instrument Burst Alert Telescope (BAT) detector array sits Cadmium Zinc Telluride (CdZnTe, CZT) semiconductor devices under a coded mask. The array has 32,768 individual Cd 0.9 Zn 0.1 Te 1.0 detectors (4 × 4 mm2 large, 2mm thick) that have a total detector area of 5240 cm2. CdZnTe materials are able to operate at room temperature for its large band gap, and also have a high average atomic number which makes them sensitive to hard X-rays (15 ∼ 150 keV). We investigate energy response of the BAT detector for which to dedicate spectroscopy and imaging in observations of GRBs.