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Diagrm of a
generic cylindrical neutron generator in a
non-nested configuration. |
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ABSTRACT:
Dr. Leung has developed a coaxial RF-driven plasma
ion source for a compact cylindrical neutron generator
that operates with high current density and produces
high atomic deuterium or tritium ion species.
The plasma and extraction electrodes electrostatically
control the passage of ions out of the ion source.
These electrodes contain longitudinal slots along
their circumferences so that the ions radiate
out of the source in a full 360 degree pattern.
The single target coaxial neutron generator with
dimensions of 26 cm in diameter and 28 cm in length
is expected to generate a 2.4 MeV D-D neutron
flux of 1.2 x 1012
or a 14 MeV D-T neutron flux of 3.5
x 1014
n/s.
An adaptation of the coaxial generator design
uses a versatile nested configuration with multiple
plasma and target layers where ion beams can impinge
on both sides of the targets to enhance neutron
yield. A generator with this nested design and
dimensions of 48 cm in diameter and 35 cm long
should generate a neutron output 10 times higher
than the single target generator described above.
Thus, D-D neutron output higher than 1013
n/s and D-T neutron output of 1015
n/s should be attainable.
STATUS: U.S. Patent #6,907,097. Available for licensing or collaborative research
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Neutron-based
System for Nondestructive Imaging, IB-1794
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Dr. Ka-Ngo Leung has been
developing neutron generators for ten years. |
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Applications:
- Imaging baggage or shipping container content,
structures and other materials
Advantages:
- Lower construction costs
- Small source for high resolution images (~2
mm)
- Several objects can be imaged simultaneously
- Produces 3.2 x 1011
T-T n/s output flux for exposure times equivalent
to large accelerator systems
Abstract:
The Berkeley Lab radiography system is compact
and expected to be less expensive to construct
than conventional accelerator systems. It is well
suited for homeland security luggage inspection
systems because the coaxial design produces multiple
beams of fast neutrons, allowing several pieces
of luggage on a carousel to be imaged at the same
time. Neutrons produced from these T-T fusion
reactions range in energy from 1 - 9.4 MeV and
therefore can image a wide range of content in
a single scan.
Dr. Leung’s generator employs a focused
ion beam accelerator with a titanium tubing target
that oscillates to minimize heat build-up while
maximizing neutron output. The 2 mm neutron source
can also be designed to generate monoenergetic
D-D or D-T neutrons or large fluxes of thermal
neutrons by incorporating a moderating device.
This potentially low cost device uses a simple
cooling system and can be portable.
Other Berkeley Lab designs can be coupled with
elements of this invention for T-T, D-D, or T-D
spectroscopic interrogation of luggage or other
samples.
STATUS: U.S. Patent #6,870,894. Available for licensing or collaborative research
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Mini
Neutron Tube, IB-1793a
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Mini Neutron Tube with
Moderate Flux
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A Larger Variation of
the Mini Neutron Tube
Design for High Flux
Applications |
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Applications:
- Homeland security: detection of explosives
and fissile materials in luggage or cargo
- Oil well logging while drilling (LWD)
- Surface analysis
Advantages:
- Extremely compact and portable: < 8 mm
in diameter and 2 cm long
- Produces 107
n/s
Abstract:
Dr. Leung and Tak Pui Lou have designed a very
compact D-D or D-T fast neutron generator in a
capsule configuration that is less than 8 mm in
diameter and only 2 cm long. This generator is
portable and is ideal for insertion into an oil
well logging drill. A larger variation of this
invention with a longer target is designed to
produce D-D neutron flux higher than 1011
n/s with a modest length and diameter. (See the
diagram below.)
STATUS: Published Patent Application. Available for licensing or collaborative research
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Ultra-short
Ion and Neutron Pulse Production, IB-1707
Applications:
- Pulsed neutron radiography or spectroscopy
- Homeland security: detection of explosives
and fissile material in cargo or luggage
- Oil well logging
- Structural evaluation
- Boron Neutron Capture Theory
- Time of flight measurements
Advantages:
- Efficiently produces pulse widths of 1 µs
or less
- Fewer neutrons are discarded
- Activation of material is avoided
- Eliminates the need to synchronize the ion
beam with a mechanical chopper
Abstract:
Dr. Leung has developed a neutron generator that
produces ultra short neutron pulses by pulsing
the ion beams instead of using a mechanical chopper.
When pulsed neutron beams are used to examine
a sample, it is possible to separate the different
types of neutron-nuclei interactions after each
neutron pulse. For many applications, pulsing
provides more complete imaging or spectroscopic
information.
STATUS: U.S. Patent #6,985,553. Available for licensing or collaborative research
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Mini
Neutron Generator, IB-1793b
Applications:
- Fast neutron brachytherapy
Advantages:
- Mobile and compact
- Radiation dose to healthy tissue is expected
to be much less than with external sources
- Clinical personnel should receive no radiation
when the source is off
- Delivers ~ 106
n/s with D-D reactions and ~ 108
n/s with D-T reactions
- Drug dose distribution around the tumor region
is designed to be tailored or eliminated
Abstract:
Accelerator-based neutron generators have been
proposed for treating tumors via brachytherapy
but the high energy accelerators necessary for
the procedure are typically too large for hospital
environments. Dr. Leung has designed a compact
D-D or D-T neutron generator specifically for
treating tumors less than 5 cm in diameter. The
generator is composed of a 2 cm x 2.5 cm plasma
source from which deuterium or tritium ions are
extracted and then accelerated. The accelerated
ion beam is then directed down a 10 cm long needle-like
tube (diameter ~ 3 mm) with a titanium target
at the end.
The neutron source can be inserted directly into
the tumor. This should minimize damage to healthy
tissue while delivering a potent dose of radiation
to the tumor. In contrast to high-dose rate 252Cf
sources, Berkeley Lab's neutron generator should
not generate any dose to clinical personnel when
the source is turned off.
Berkeley Lab is seeking a qualified industrial
partner(s) to further develop this technology.
Please visit the following page for more details:
http://www.lbl.gov/tt/collaboration/techs/brachytherapy.html
STATUS: Published Patent Application. Available for licensing or collaborative research.
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Compact
Spherical Neutron Generator, IB-1675
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Diagram of Berkeley Lab's
spherical neutron generator for high resolution
imaging. |
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Applications:
- Neutron radiography
- Explosives detection in luggage or cargo
- Land mind detection
- Spent fuel, nuclear, and toxic waste analysis
Advantages:
- High brightness
- Works like a point source
- High Flux
- High neutron yield
- Safe D-D reactions
Abstract:
Dr. Leung has developed a compact spherical neutron
generator that can use safe deuterium-deuterium
(D-D) instead of radioactive deuterium-tritium
(D-T) or tritium-tritium (T-T) reactions, and
still provide a high neutron flux. This generator
is designed with a small, spherical shell-shaped
RF-driven plasma ion source surrounding a multihole
extraction electrode which in turn surrounds a
spherical target. Ions passing through the holes
in the extraction electrode are focused onto the
target, which is loaded with D or T by the impinging
ion beam. Neutrons are emitted at all angles from
the spherical generator.
STATUS: U.S Patent #7,139,349. Available for licensing or collaborative research
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