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ANTECH Model
2442
Active Well Coincidence Counter (AWCC)
 The Active Well Coincidence Counter (AWCC) is a
transportable high-efficiency counter for the measurement of both uranium
and plutonium. Originally developed by the Los Alamos National Laboratory
(LANL), the ANTECH variant contains the basic LANL ideas with added
performance-enhancing features. These include:
De-randomizing buffer mixer circuit to reduce count losses
Built in totals counter associated with each amplifier channel
Robust mechanical design including lifting fixtures
For uranium measurement the AWCC is used in Active Mode.
Two americium-lithium neutron sources are inserted – one in the base and one
in the plug unit – and the AWCC is operated in random driver mode.
Uncorrelated neutrons produced by the Am-Li sources induce fission in U-235
samples in the measurement chamber. The coincidence counter electronics of
the ANTECH Advanced Multiplicity Shift Register can be used to determine to
coincidence count rate, which is attributable to the induced fission in
U-235. Using this method the mass of uranium is readily determined.
Two Action Modes are available depending on the size of the
U-235 sample.The AWCC in Thermal Active Mode is most
appropriate for measuring low-enriched uranium materials. In this mode the
sleeve and end plug cadmium coverings are removed. The detection level in
this mode is approximately 1gm of U-235.
Fast Active Mode is employed for the
measurement of highly enriched material such as uranium metal, uranium
thorium fuel and LWR fuel pellets. In this mode the cadmium plates and
sleeve are inserted and the detection limit is approximately 23gm of U-235.In Passive Mode the Am-Li neutron
sources are removed and the AWCC can function either as a neutron
coincidence counter or a neutron multiplicity counter, again using the
appropriate features of the ANTECH AMSR. The detector measurement chamber
can be enlarged by removing the two internal polyethylene disks and the
nickel reflector. It can also be operated in the horizontal position with
the end plugs removed and with a material test reactor (MTR) holder in
position for the measurement of uranium in MTR measurements.
Specifications
- Am-Li sources: 4.8 x 10,000 n/sec (2 off)
- Detection efficiency: 26% to 31%
- High Voltage: 1,680 volts
- Weight: 130 kg approx
- Overall envelope including handle and frame: 71.1
cm long x 63.5 cm wide x 104
cm high
- Adjustable measurement chamber: 20.6 cm high
x 22.9 cm diam. (8.1" x 9")
- Electrical connections:
- High voltage - SHV, 5
V supply for head amlifiers - BNC, Signal
output - BNC, Mixer RS-232 output— 9
w male 'D'
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