roughness effects, and neglect of very low energy emitters.
As discussed in references 2 and 3, the field spectrometric
exposure rate estimates are very insensitive to local
inhomogeneities in isotope concentration, small errors in
relaxation length, or slight ground roughness effects as
opposed to the large errors which would be obtained by
calculating the exposure rates using concentration data from
an atypical soil sample.
This is due primarily to the fact
that the spectrometer "sees" a large area of soil and
averages out most of these inhomogeneities.
The estimates of the percentage of the total exposure
rate due to each emitter obtained from both the soil concen-
tration data and the field spectrometric data agree quite
well and these estimates, whenever given, are probably fairly
reliable keeping in mind that on many of the islands they are
based on just one soil sample from a single location.
Error in TLD Results - The accuracy of the exposures obtained
from the
with the
HASL TLD
although
TLD data {see Table 1) is best indicated by comparison
ionization chamber results at mutual sites.
The
data seem to agree fairly well on the average,
a few individual values appear to be quite far off.
The NRDL TLD data appear to be about 20% higher on the
average with larger variations.
Overall Consistency of Data - The overall consistency of the
ionization chamber and spectrometric measurements, TLD
results, and calculations from the soil analysis indicates
that the range of exposure rates on each island and the
major contributors to these exposure rates have been
determined quite accurately.
This consistency is verified
by the data in Table 1 and the data discussed in the next
section.