BATSE consists of eight modules, one at each corner of the GRO spacecraft. In each module are two detectors: a Large Area Detector (LAD) and a Spectroscopy Detector (SD). The electronics are distributed between the detector modules and a unit within the spacecraft.
The LADs' primary function is the detection and localization of bursts. These detectors are built around a thin (1.27 cm wide) NaI(Tl) detector with an area of 2025 cm^2. Only the front surface is shielded actively while passive shielding is utilized on the sides and back. The LADs are currently operated in the 40-600 keV band.
Designed and built at UCSD, the SDs were optimized for accumulating a series of spectra across a burst with good temporal resolution. Each detector consists of a thick NaI(Tl) crystal monitored by a single photomultiplier tube. The crystal has an area of 127 cm^2 and a height of 7.6 cm. These detectors are only shielded passively by the aluminum case with a beryllium window on the front surface. Depending on the photomultiplier gain, the SDs can accumulate spectra between 15 keV and 20 MeV. Currently the SDs are operated in the range 5-1,500 keV to maximize the sensitivity to absorption lines in the 15-100 kev (cyclotron lines) and emission lines around 400 keV (redshifted annihilation lines?) bands.
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This page is maintained by David Band, band@ucsd.edu