The Technology:
The LENG is a new type of neutron generator in which the ion beam is directed
onto a large-area target, thereby greatly reducing the power density on the
target and its sputtering in comparison to other generators. As a result the
LENG has been demonstrated to operate for 3,000 hours in dc tests at a neutron
energy of ~2.5 MeV (D-D reaction) and an output neutron flux of 108
n/s. Pulsed operation has been achieved at the same flux level with 30 µs pulses
at 500 Hz. The pulse length has been varied over the range of 10-40 µs and
the pulse repetition rate over the range of 10-1000 Hz; it is expected that
operation can be extended well beyond these ranges.
The LENG tube is shown below.
The copper-gasket flanges are 8 inches in diameter and the overall length of
the tube is 22 inches (from the end of the pinch-off to the cable output).
Work is underway to modify the design to replace the flanged seals with welded
seals, thus significantly reducing the overall diameter of the tube. The electronics
are housed in a 36 inch-high electronic rack that is connected to the tube by
a 30-foot cable bundle. The power input requirement is approximately 300 W
at 110 VAC. The tube is water cooled.
Applications:
The LENG operating at a neutron output energy of ~2.5 MeV is particularly attractive
for applications including: (1) NDA of nuclear waste; (2) analysis of munitions;
(3) detection of mines and unexploded ordinance; (4) detection of explosives,
drugs and chemical warfare agents; (5) industrial process control; and (6) nuclear
safeguards and treaty verification.
Project Status:
The dc performance of the LENG has been well established. Work is now underway
to fully develop its pulsed capabilities for applications to prompt gamma neutron
activation analysis (PGNAA) and differential die-away measurements.
ACKNOWLEDGEMENT: This work was supported in part by the U.S. DOE under contract No. DE-FG03-96ER82173. This support does not constitute an endorsement by DOE of the views expressed herein.