Health Physics Society Annual Meeting, Denver, Colorado, June 16-20, 1968 TITLE: External Radiation Survey of Bikini Atoll - May 2967 ee ee AUTHOR(S): Harold L. Beck and Burton G. Bennett, United States Atomic Energy Commission, Health NY . . and Safety Laboratory (HASL), aiidTommy F. McCraw, United States Atomic mergy ADDRESS: Commission, Division of Operational Safety, Washington, D. C. ABSTRACT (double-spaced): Abstracts exceeding 200 words will NOT be considered. An intensive radiological survey of the islands of Bikini Atoll was conducted in late April and early May of 1967, nine years after cessation of extensive testing of nuclear devices in the area. The survey included general observations of the prevailing environmental conditions and a detailed investigation of external environmental radiation levels. Ex- posure rates due primarily to penetrating gamma radiation were measured, and the principal radioisotopes contributing to the total exposure rate on each of the major islands of the atoll were determined. Instrumentation utilized included a field gamma spectrometric system, a high pressure ionization chamber, scintillation and G.M. survey meters, and thermoluminescent dosimeters. A large number of soil samples were taken for laboratory NaI(T1) and Ge(Li) gamma spectral analysis. Total exposure rates were found to vary considerably from site to site and island to island. Levels measured over soil ranged from less then 10 wR/hr to over 500 uR/hr with the highest levels usually found in the more thickly vegetated areas. included 137 60 Cs, Co, 125 Major contributors to the radiation fields usually Sb, and 102m Rh, although, a large number of other isotopes were also detected. sendthisoriginalpius 15 copies to: oo6 STB Y : E.G. Struxness, HealthPhysics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 DEADLINE: February 1, 1968 \