DELETED (SEMINOLE) ——?Project 2.64 - Fallout Location and Delineation by Aerial Survey R. Graveson OBJECTIVE To evaluate the attenuation of radiation in air. DESCRIPTION AND EXPERIMENTAL PROCEDURES A portable gamma spectrum analyzer was mounted in a helicopter. The helicopter was to hover at altitudes of 1000, 800, 600, 400, 200, 100, and if possible 50 feet over the surface of an island, open sea water about 1 mile from land and the lagoon about 1 mile from land. At each position a spectrum was to be taken, RESULTS An inverter failed shortly after reaching the area of interest and no spectra were obtained. Total gamma intensity measurements were obtained by making passes over Engebi (Janet) and the lagoon to the west of Engebi (Janet).at the planned altitudes, AM This data is being evaluated, Ay