=» Project 2.65 - Analysis of Fallout and Base Surge - M. Morgenthau OBJECTIVE To survey the close-in residual contamination field resulting from the ‘Sebco. ) shot. DESCRIPTION AND EYPEPIMONTAL PROCEDURES For this event the project hed only limited participation, consisting of an eerial survey on i, Mtl, end M+2 days, The survey was made of the portion of Eniwetok Atoll contaminated to a sigenificent amount by this event. included the islands tetween Engebi and Aomon. This Particular attention wes paid to the residual conteminetion on Rujoru, Eberiru, end Aomon, The measurements were taxen by means of a probe on a long catle suspended below a hovering helicopter. The position of the probe was determined by reference to charts and aeriel photographs. RESULTS Aerial survey readings teken on three successive days were corrected for meter calibration and corrected to H+l hour values as shown in Table 2.65-1 by using the decay exponent of -1.10. This decay exponent was determined from a plot of field dose rate readings vs time for three of the islands surveyed as shown in Fig. 2.65-1, These particuler islends were chosen for this plot because of their low background prior to the shot. Ht+l hour extrapolated readings for Eberiru Island are skown in Fig. 2.65-2. _ yt