The COS-B experiment for gamma-ray astronomy.

The experimental package on-board the COS-B satellite is described. Extraterrestrial gamma radiation sources are investigated by observing of gamma rays with energies in excess of 20 MeV. Major areas studied are: the angular structure of gamma ray emission from the galactic plane, the flux of the isotropic radiation from high galactic latitudes believed to be of extragalactic origin, point sources of the radiation, and determination of the energy spectra of all identified sources. Instrumentation included in the experiment are: a 16-gap spark chamber for the identification and determination of the arrival direction of the gamma quanta, a cesium-iodide energy calorimeter for energy determination, a telescope defining the field of view of the experiment, a plastic scintillator anticoincidence shield for the rejection of charged particles, and a proportional counter sensitive to X-rays in the 2 to 12 keV range to synchronize on the possible short period pulsations of gamma ray emission from sources detected to pulsate at X-ray wavelengths.