Swift's instrument : Burst Alert Telescope (BAT) the detector plane The BAT detector plane consists of 32,768 pieces of 4 x 4 x 2 mm cadmium-zinc-telluride (CZT). These CZT detectors are arranged into a four-tiered hierarchical structure. Arrays of 8 x 16 CZT detectors are arranged by twos into detector modules. Eight such modules are combined to form a detector block, and sixteen blocks make up the entire detector plane. This hierarchial structure, along with the coded-aperture imaging, allows the BAT to continue operations even with individual pixels, whole arrays, modules or even blocks missing.