IPNS' success paved way to newest neutron source for materials research
ARGONNE, Ill. (April 21, 2006) — When the Intense
Pulsed Neutron Source at
the U.S. Department of Energy's Argonne National Laboratory began operations
in 1981, few could envision that it would lead to the $1.4 billion Spallation
Neutron Source, beginning operations this spring on the grounds of Oak
Ridge National Laboratory in Tennessee.
The Spallation Neutron Source, or SNS, is a unique collaboration of six Department
of Energy laboratories, each bringing particular expertise to the design, construction
and operation of the facility, which will provide the most intense pulsed neutron
beams in the world for scientific research and industrial development. The
SNS is about 10 times more powerful than existing neutron sources anywhere
in the world, and will help sustain America's scientific leadership and economic
competitiveness.
Neutron science helps develop new materials that are stronger, lighter, and
cheaper yet perform well under severe conditions. More than ever, major research
facilities, such as X-ray and neutron sources, are used to understand and engineer
materials at the atomic level. Such materials have greatly improved properties
offering both better performance and new applications.
Some examples include electronic devices, which require smaller and faster
components. Commercial and military aircraft as well as space probes need new
lighter alloys and stronger welds for higher speed and lower fuel consumption.
Automobiles are using more high-temperature materials, lightweight alloys,
and plastics to become more fuel efficient and less polluting. Computers require
ever-increasing storage capacity using magnetic materials. New high-temperature
superconducting materials promise more efficient motors and power transmission.
And designer drugs and genetic engineering are revolutionizing medicine and
health care. Neutron-scattering research plays an important role in all these
areas and more.
Neutrons—uncharged particles found in the nuclear core of nearly all matter—are
useful for materials research because of their penetrating power. X-rays and
electrons, which are also used to study materials, typically penetrate only
a few ten-thousandths of a centimeter inside materials. But neutrons can punch
through several centimeters of steel, so experimenters can study materials
inside pressure cells and furnaces. Neutrons are also uniquely useful for studying
materials that contain atoms of the lighter elements, such as hydrogen and
oxygen. Much of what is known about the atomic motion and structure of high-temperature
superconductors—metal oxides that can carry electricity without energy loss—was
discovered at neutron sources like the IPNS.
Carpenter to receive neutron scattering award
ARGONNE, Ill. (April 21, 2006) — Jack Carpenter of the U.S. Department
of Energy's Argonne National Laboratory will receive the 2006 Clifford
G. Shull Prize from the Neutron
Scattering Society of America for his groundbreaking work developing
neutron sources and instrumentation. More... |
Neutron-scattering research has been an important scientific tool worldwide
for many years, most of it carried out at research reactors, whose neutron
intensities have reached their engineering limits. In the early 1970s, Argonne
scientists, led by Jack Carpenter, now IPNS technical director, built up a
series of first-of-a-kind experiments, pioneering the development of accelerator-based
pulsed spallation neutron sources. The experiments eventually led to Argonne's Intense Pulsed Neutron Source, or IPNS, one of the earliest examples of
a neutron source with full research capability. Over its 25 years of operation,
the facility has provided the nation's most reliable source of neutrons for
the study of atomic arrangements and motions in liquids and solids—information
key to developing new materials—and has hosted thousand of users from around
the globe.
The IPNS's popularity and the elegance of its instrument designs belie its
humble beginnings. At the outset, it was built with equipment cannibalized
from earlier projects and given only bare-bones funding in the beginning. Yet
over the years it grew to become one of the country's leading facilities for
research in condensed-matter physics. The instrumentation designed and developed
at IPNS forms the core for the design of the neutron-scattering instrumentation
for the SNS. Meanwhile, pulsed spallation sources in other laboratories worldwide
have also provided important contributions to science and to the development
of the new technology.
Argonne researchers, working closely with Oak Ridge National Laboratory scientists,
have been primarily responsible for developing the neutron-scattering instrumentation
and experiment facilities for SNS. SNS will initially have one target station
operating at a frequency of 60 Hertz (Hz). Two "thermal" moderators
and two "cold" moderators will serve 18 beam lines, and a variety
of instruments will be constructed on these beam lines.
“The world-class instruments that are being built for SNS are the most
efficient in the world, and will allow users to take full advantage of the
high intensity of the SNS,” Carpenter said. Three of the Argonne-developed
instruments will be installed and functioning in the SNS when it becomes operative
later this year, and a fourth, still in development, will be available about
a year later. An additional four instruments will be added at intervals as
they are tested and ready for deployment as the power of the SNS increases.
In addition, other instruments are being proposed for funding and later development,
Carpenter said. The SNS offers space for a total of 24 instruments, several
of which will be constructed as the need for them arises.
For the experiment facilities, SNS expects 1,000 to 2,000 users each year
from all walks of science and industry. Because not all these users will be
experts in neutron scattering, SNS will provide scientists and technicians
to maintain and operate the instruments and work closely with the user community.
The six-laboratory partnership in designing and building the SNS is an unusual
one, Carpenter said, but has worked “amazingly well. A partnership on this
scale has never been done before, and it's a remarkable success. It's a tribute
to the management of SNS, but also to the good spirit of the partner labs,
who have developed a conscious, consistent collaboration.”
The $1.4 billion facility has been under construction since 1999 and is being
completed both on time and on budget with more than 7.5 million work-hours
with only two lost work-days from injury, a remarkable accomplishment. The
energy of the SNS proton beam is 1 billion electron volts, equal to 666,000,000
D-cell batteries joined end-to-end. The beam accelerates through the linear
accelerator from a standstill to approximately 90 percent of the speed of light
in two microseconds, and the energy striking the target is similar to a 200-pound
block of steel hitting the target at 50 miles per hour. The placement of that
beam to the target requires such precision that the Earth's curvature was factored
into the construction of the linear accelerator—a
tiny but critical difference of 7 millimeters from one end of the 1,000-foot
accelerator to the other. —
Catherine Foster
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