The discrepancy between the soil sample and the spectrometer exposure rate results indicates the problems involved
in obtaining a representative soil sample.
The agreement in
the values of the percentage exposure rates is quite good

verifying the two assumptions discussed in Section II.

Both the field spectra and the laboratory spectra

indicated that isotopes other than *°’cs, °°co, and *#5sb

were also present in the soil.
The energies and/or concentration of these isotopes, however, were too small to
contribute significantly to the total exposure rate.
In
order to more accurately determine the identities of these
isotopes,

samples of the

soil

at Locations 5

analyzed by Ge(Li) spectrometry.

and 7 were also

These spectra indicated the

presence of *°°Ru, *°*Eu, ***am, and possibly *°°Rh in

addition to the isotopes already mentioned.
An unidentified
weak 238 keV emitter was also detected (see Figure 8).

NRDL LiF TLD dosimeters were placed every 150 ft. along
this transect.
HASL TLD dosimeters were placed near spectrometer Locations 1, 2, 3, 4, and 5, although in the case of
Location 2 the TLD dosimeter was not exactly in the center
of the measurement site.
In most cases the TLD's were taped
to branches along the transect.
In general, the TLD results
show the same trend as the other total exposure rate data

(see Table 1), although the NRDL results are slightly higher

on the average.

In order to determine if there was any significant
difference in exposure due to the proximity of dosimeters to

vegetation, a dosimeter of each type (NRDL and HASL) was
placed on a stake in the middle of the open trail at Location
5 for comparison with the two taped to the vegetation.

For

this location, at least, there was no significant difference
in the readings of the two sets of dosimeters.
The high
readings of the HASL dosimeter at Location 2 are probably

due to the highly variable nature of the radiation field.

This dosimeter was taped to a branch of a bush in a general

area where the radiation field appeared to be lower than

average as evidenced by the area survey results.
However,
it is quite possible the vegetation in this generally sandy

-~ 21 -

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