Gamma-Ray Astronomy in Space in the 50-KEV to 3-MEV Region

The γ-ray fluxes in space which arise from nuclear and plasma interactions are expected to be of the order of 10-1to 10-2photons/cm2.sec. A considerable γ-ray backgrond is produced from the interactions of cosmic-ray nucleons. A detection ystem is described which will allow the measurment of considerably weaker primary fluxes than previous experiments. The apparatus is to be placed on a low-altitude, low-latitude earth satellite. A scintillation counter with a shielding collimator is used in the 50-150 key energy region. In the 0.3 to 3.0 Mev region, the high particle flux requires the use of an anticoincidence shield arond the scintillation counter. A Compton coincidence telescope provides directional collimation in this energy region. Data from the detectors are entered into a temporary binary storage and are read out, together with identification and satellite orientation information, to the payload telemetry system at a one bit/sec rate. The entire apparatus weighs 30 pounds, has a complemnt of 400 transistors, and operates on 650 my of power.