Beta Assayer
The detector unit is a thin, massless (i.e., no attenuation correction
required) gas (90 percent argon, 10 percent methane), proportional
counter with multiple aluminum absorbers.
On wastes aged ten years or
more, laboratory tests show that both strontium-90 and cesium~137 can be
assayed in the nanocurie per gram sensitivity range.
The counting
statistics reliability is a +10 percent.
The unit was completed and
tested in the field.
It is mounted on a pushcart with large balloon
wheels for transport across the desert terrain.
The electronics and
sensing element are all on the cart, with the power system being supplied
by a vehicle with a 110-volt generator.
DEV-VAN-I
This is a van housing an argon dosimeter for measurement of 50 to 1,300
milliroentgens per year, an alpha water meter for assaying below maximum
permissible concentration (MPC) levels, several NaI(Tl) portable instru-
ments, a neutron counter with directional probe and the key detector
systems, a Ge(Li) collimated unit (see Figure 1), and an L-X-ray system
for determining plutonium and americium at nanocurie to picocurie levels.
The unit is completed and is being field tested.
DEV-VAN-ITI
This development van is for in-van core collimated assaying and downhole
radionuclide assay.
Precision draw works for depth accuracies Zn the
centimeter range are required.
A directional system allows 360
coverage
using windowed Ge(Li), intrinsic germanium, neutron, and Nal(Tl) detectors.
Both plume characterization and movement with time
DEV-VAN-II at the picocurie to microcurie levels.
picture of the van with a boom on the end to allow
distance between van and wells to minimize cave-in
at burial grounds or cribs.
will be determined by
Figure 2 shows a
attaching tools and
problems, especially
DEV-VAN-TIIT
This van is in the planning stage and involves a californium-252 activa-
tion source for determining downhole plutonium and uranium, and various
matrix parameters such as density, porosity, void volume, and elemental
compositions.
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