a (FLATHEAD) Project 2.64 = Fallot cation and Delineation by Aerial Survey - R. Graveson Objectives To survey the gamma radiation from fallout contaminated ocean areas using an aircraft borne detector. To make air absorption measurements to correlate the aircraft data with the intensities measured at the surface of the sea, Description and ExperimentalProcedures Three P2V-5 aircraft were equipped with gamma radiation detectors to record the dose rate arriving through the thin aircraft skin from a water surface below, “ Two aircraft flew over the fallout area simultaneously and observed the radioactivity and altitude (operating altitude 200~400 feet). The in- formation on radiation dose rate and altitude was to be continuously recorded and telemetered to the Program Two Control Center aboard the USS ESTES. Results On D day both aircraft became contaminated due to insufficient data on the time of cessation of fallout. Fallout extending some 40 miles west of Bikini was located before the aircraft became contaminated, On D # 1 day two aircraft surveyed an area bounded by 163°40'E to 166°00'E and 11900'N to 13920'N, The contaminated area was located and delineated within this area, There was apparently some fallout still occurring approximately 60 to 100 miles north and northwest of Bikini, Both aircraft became contar- inated in this region. Lint200g On D # 2 one aircraft was used but due to its residual contamination 6 careful study of the charts from the aircraft must be made to obtain def~ initive data. This analysis is being made, oe: ® oy CG a, - id