The capability of COS-B to measure cosmic gamma ray bursts.

The COS-B experiment for gamma ray astronomy features a large area plastic scintillator, 1 cm thick, for the detection and rejection of charged particles entering the experiment. Tests with radioactive sources have confirmed that the effective area of this detector is several hundred square centimeters for the detection of gamma rays of energy greater than 100 keV. Additional electronics included in the payload to define the energy window of interest, provide the burst trigger and format the digital data. A continuously over-written temporary memory will provide 'precursor' data prior to the burst trigger. Use is made of part of an 9 kbit memory associated with the telecommunications subsystem to buffer the burst data. Burst onset time will be determined to the order of a millisecond which, given the highly eccentric orbit of COS-B, should enable sources to be located to better than one degree using the triangulation technique with other satellite observations.