HILL — Scientists at the University of North
Carolina at Chapel Hill and a UNC start-up company,
Xintek, Inc., have invented a new X-ray device based
on carbon nanotubes that emits a scanning X-ray beam
composed of multiple smaller beams while also remaining
As a result, the device can create images of objects
from numerous angles and without mechanical motion,
which is a distinct advantage for any machine since
it increases imaging speed, can reduce the size of
the device and requires less maintenance.
report on the promising invention appears in this
issue (May 9) of Applied Physics Letters, a science
and technology journal. The physicists already
have received U.S. patents on elements of the work
and expect more to be granted.
"This technology can lead to smaller and faster
X-ray imaging systems for airport baggage screening
and for tomographic medical imaging such as CT (computed
tomography) scanners," said Dr. Otto Zhou, Lyle
Jones distinguished professor of physics and materials
sciences in UNC's College of Arts and Sciences.
"We believe this is an important advance in
X-ray technology, and we are extremely excited about
it," Zhou said. "If it works as well as
we think it will, other advantages will be that scanners
will be cheaper, use less electricity and produce
Other authors of the paper are physics doctoral
students Jian Zhang and Guang Yang and Dr. Jian Ping
Lu, professor of physics and astronomy at UNC, Dr.
Yueh Z. Lee of the UNC School of Medicine and Dr.
Yuan Cheng, Dr. Bo Gao and Qi Qiu of Xintek, Inc.,
a Research Triangle Park, N.C.-based nanotechnology
Scientists and others, including the news media,
have shown strong interest in carbon nanotubes because
of numerous potential applications, Zhou said. Discovered
about a decade ago, the tiny bits of carbon are very
strong tubular structures formed from a single layer
of carbon atoms and are only about a billionth of
a meter in diameter.
Industrial and university researchers around the
world are now developing new devices using the nanotubes,
such as field emission flat panel displays, high-strength
composites and high energy-density batteries.
The UNC researchers demonstrated that carbon nanotubes
might be used as X-ray sources and received their
first patent in 2000. Prior to that, conventional
X-ray tube design had not changed much in a century.
The nanotube X-ray technology allows the device
to be operated at room temperature rather than at
the 1,000 degrees Celsius that conventional sources
require. It can also be operated as a high-speed
X-ray camera, capturing clear images of objects moving
at high speed. The team has now received two U.S.
patents on the general concepts of nanotube X-rays.
Xintek, the UNC spin-off, is working with several
manufacturers to commercialize the technology.
"When fully developed, devices should lead
to more effective imaging systems for homeland security," Zhou
The new invention can create images of various objects
from numerous angles without mechanical motion, he
In conventional CT scanners used in airports for
baggage screening and in hospitals for diagnostic
imaging, the X-ray source is mechanically rotated
around objects, including patients, to collect the
many projection images required to construct a three-dimensional
picture, Zhou said. Existing scanners are large and
"In addition, the imaging speed is relatively
low," he said. "The new scanning X-ray
source using nanotubes can electronically produce
X-ray beams from different angles without moving.
This can significantly increase the imaging speed
and reduce the size of the scanner. Making this technology
smaller, faster and more accurate should boost the
effectiveness of airport baggage scanners significantly."
Inc., which seeks to develop new industrial and
medical applications for carbon nanotubes, resulted
from Zhou’s group's work. Support for the research
has come from the U.S. Transportation Safety Administration,
the National Institutes of Health and private sources.
Note: Zhou can be reached at (919) 962-3297 or Zhou@physics.unc.edu
News Services contact: David Williamson, (919) 962-8596