~3—
Pasurements of samie-rey enlisting Pission proguces have ves
aoe
a
made periodically on soils sollected at tha irgorne National Laboratory
site siswe the spring of 1957.
Tho measuring teehniara orvloyed was
that of gamma-ray apectromstry of soll samples of finite wise (1-2 zg}
:
using a 5° by 4° Nal eryeteal and en aygonne Pyve 256 channel analyser.
The soil was geometrically arranged by means of a steimiess obesl
eontainer into a one inch layer sromd and over the exyatal (6).
Beckground reduction, essential for the detection of the quantities
rm ,
7
sample and dstector.
&
+
ce
2
3
3
was effected througn the uss of thick stesl shieldiag az
iferry
of achivity involved (approximately 10”10 ouris of os?! fkg of soil),
Soil sampling was dons to a depth of 6 inehes
go thet essentially all fission products present over a given aren
yers inciuded.
Two gamma-ray spectra of soll taken with en Ral
erystal are shown in Figure 2,
The one from deep soil is free of
sny fission activity end contains only Th, 0, ane °°. The other,
from soil collected in July 1959, indicates the sresence cf two peaks
not eyident in the first case.
Tha one seal is due to Beoily9
and the other to Ru} ,106,
The concentration of fission and natural radicactivity in soit
was de
determined by the use of sources cf tmown acbiviby imeorperated
in moek soil (HagFO4) >
The wethed presupposss imovledes of the varions
isotopes present in the soil,
The stenderd reference spectra, ome for
each isotope, permit setting up the fraction of the total counting
rate oceurting in orxch spostrel region, there being
ea many regions
238
Los
e
Te
MB RCH EES