A hard X-ray survey using BATSE/CGRO data

No hard X-ray all-sky survey has been conducted since HEAO 1 A4 mission fro m 1977-1979. The hard X-ray detectors of the BATSE experiment aboard the Co mpton Gamma Ray Observatory have monitored the hard X-ray sky continuously since April 1991. We are attempting to conduct a sensitive all-sky survey u sing BATSE data in the 20-300 keV band, by combining an earth occultation i maging technique with a sophisticated background model. Our sensitivity wil l be at least 5-10 improvement over the HEAO 1 A4 survey sensitivity. In th is paper we will describe the background analysis and some of the results w ill be outlined.