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