Thies system has a background of about 50 counts per minute
and an efficiency of approximately 38 per cent based on p32,
The counts for biological samples were converted to disinte-
grations per minute per gram (d/m/g) of wet tissue and the
counts for samples of island soil and beach sand were converted to d/m/g of dry material at time of counting by applying correction factors
for sample weight,
counter efficiency,
and self-absorption.
The values
for gross beta
activity in the
appendix
tables are given in d/m/g plus or minus the 95 per cent
counting
error,
which was obtained from nomographs based on
the ratio of the counting rate and total time of counting of
the sample to the counting rate and total time of counting
of background (Kinsman,
1957).
tables,
however,
Tables 2 and 3,
The values in the summary
have been calculated in
terms of micromicrocuries per gram
(yjc/g)
of wet tissue.
The samples collected in 1958 were analyzed for gamma-
emitting isotopes with a 3 x 3-inch sodium iodide crystal
DOE ARCHIVES
connected to a Radiation Counter Laboratory 256<-channel analyzer.
The radioisotopes present in the samples were identi-
fied by their gamma energies and for some of the samples the
amount of each radioisotope was determined
by a subtractive