-6procedure similar to that described by Lowman et al.
The counts per minute
(c/m)
(1957).
for each radioisotope were con-
verted to disintegrations per minute (d/m) by applying the
correction factors listed in Table 1.
The size of the
sample affects the geometry,and the correction factors listed
do not include error due to the differences in geometry
between the biological samples and the radioisotope standards
used to calibrate the efficiency of the counting system.
This error ranged from 10 per cent for the smallest biological samples to 60 per cent
for the largest samples.
The appropriate decay-correction factor was applied
also to correct the values to the date of collection,
Table 1.
Correction factors used to convert
gamma counts to disintegrations
Radioisotope
x40
Correction
factor
409
cei3?7
16.5
zn°5
54
Zn? -Nb?>
14.5
cos?
8.6
cel44_p,-144
40
wi8s
Ru206 _py106
9.6
66.4
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