Appendix 14 Gamma 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 December 1974. The measurements were made with a Reuter-Stokes environmental radiation moni- tor, model RSS-111, which uses a pressurized ion chamber as a detector. response of this instrument is relatively independent of gamma-ray energy The (45%) for incident photons from about 0.2. to 4 MeV. (The largest contributor to the gamma background at Bikini is 137¢g 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 interior of Bikini Island along the "center baseline" road indicated gamma exposure rates from 3 to 6 times as high as the village averages. 1975. Location A detailed survey of the interior is planned for early Gamma exposure rate %%l m above floor or ground, uR/hr Annual gamma exposure, mR Inside Inside Back yard House #4 7.8 13.2 House #20 8.0 7.7 70 67 House #28 9.3 15.5 81 136 House #40 9.3 15.5 81 136 75 114 Average - 154 - 638 . Back yard 116