Appendix 14 Catta Radiation Measurements on Bikini Island, 1974 External gamma exposure rate measurements were made by N. A. Greenhouse and V. A. Nelson in the village area on Bikini Island during Lecember 1974, . The measurements were made with a Reuter-Stokes environmental radiation monitor, model RSS-l11, which uses a pressurized ion chamber as a detector. The response of this instrument i94 relatively independent of gamma-ray energy (+£5%) for incidence photons from about 0.2 to 4 MeV. (The largest contributor toe the gamma background at Bikini ts 137¢5 with a gamma energy of 0.667 MeV.) The results, which include cosmic-ray background (+4 uR/hr; ~35 mR/yr), are given in the table below. Measurements made through the interfor of Bikini Island along the “center baseline” road indicated gamma exposure rates from } to 6 times as high as the village averages. A detailed survey of the interfor is planned for early 1975. Gamma exposure rate vl m above floor or ground, uR/hr Annual gamma exposure, mR locazion Inside Back yard Inside Back vard House #4 7.8 13.2 68 1l6 House #20 BO” 7.7 70 6? House #28 $.3 136 House #46 Average 116 rr eee . we ee phe ES Maa >Mia ls 114