Create Bose-Einstein 'Super Molecule'
super-cold collection of molecules behaving in perfect unison
created for the first time from a sea
of “fermion” atoms by researchers at JILA, a joint
institute of the National Institute of Standards and Technology
(NIST) and the University of Colorado at Boulder (CU-Boulder).
are a class of particles that are inherently difficult to coax
into a uniform quantum state. The ability to meld fermions
into this state—a soup of particles that acts like one
giant, super molecule—may lead to better understanding
of superconductivity, in which electricity flows through certain
metals with no resistance.
color images of the molecular Bose-Einstein condensate
Left—A cloud of gaseous fermionic
potassium cooled to 250 nanoKelvin and paired into bosonic
Right—The same experiment starting
at 90 nanoKelvin where the molecules collapse into a Bose-Einstein
condensate. In both images higher areas indicate a greater
density of atoms.
For a high resolution version of this image, contact Gail
work was described in a paper posted Nov. 7 on the informal physics
archival Web site at http://arxiv.org
and will be published online by the journal Nature on
Nov. 26. Researchers Deborah S. Jin of NIST and Markus Greiner
and Cindy A. Regal of CU-Boulder reported that they created a
Bose-Einstein condensate (BEC) of weakly bound molecules starting
with a gas of fermionic potassium atoms cooled to 150 nanoKelvin
above absolute zero (about minus 273 degrees Celsius or minus
459 degrees Fahrenheit).
describes her team’s
work as the “first molecular
condensate” and says it is closely related to “fermionic
superfluidity,” a hotly sought after state in gases that
is analogous to superconductivity in metals. “Fermionic
superfluidity is superconductivity in another form,” says
Jin. Quantum physicists are in a worldwide race to produce
fermionic superfluidity because gases would be much easier
to study than
solid superconductors and such work could lead to more useful
more details, see www.nist.gov/public_affairs/releases/super_molecule.htm.
X-ray image produced by a dense array of rectangular
a high resolution version of this image, contact Gail
Inspection May Meet Computer Chip-Making Need
decades-old, X-ray-based method for studying the atomic structure of materials may be the answer to a looming semiconductor industry need—a
rugged, high-throughput technology for measuring dimensions
of chip circuitry packed with devices approaching molecular
led by National Institute of Standards and Technology (NIST)
scientists recently reported* their initial success in adapting
small-angle X-ray scattering (SAXS) to rapidly characterize
the size and shape of grid-like patterns with nanometer-scale
linewidths. With better than one nanometer (billionth of
a meter) precision, the team determined the average size
of periodically repeating features arrayed on three chemically
different samples much like the intricately patterned polymer
masks used to print integrated-circuit designs.
size of on-chip devices soon to shrink to below 100 nanometers,
current dimensional measurement tools are approaching
their limits. The versatile SAXS method, the team suggests,
could be an able substitute. It can be used on a wide range
of materials to evaluate the quality of surface and subsurface
patterns consisting of features considerably smaller than
experiments supported by the Defense Advanced Research Projects
Agency, NIST, and the U.S. Department of
Energy, essential data were gathered, within a second,
over an area about 40 micrometers on a side—a large
swath, nanotechnologically speaking. Images assembled from
X-rays deflected by electrons
in the samples yielded high-precision measurements of linewidths,
spaces, line-edge roughness, and feature geometry.
the SAXS method actually should become easier as feature
sizes decrease and near molecular dimensions,
explains NIST’s Ronald Jones.
to NIST polymer scientists, the team included researchers
from ExxonMobil Research Co., Argonne National
Advanced Photon Source, and the Shipley Co. For more
details, see www.nist.gov/public_affairs/newsfromnist_says.htm.
Mark Bello, (301)
L. Jones, Tengijao Hu, Eric K. Lin, Wen-Li Wu, Rainer Kolb, Diego
M. Casa, Patrick J. Bolton, and George G. Barclay, “Small
angle X-ray scattering for sub-100 nm pattern characterization,”
Applied Physics Letters, Vol. 83, Issue 19, pp. 4059-4061.
perspective view of a mocked-up wall section. Red circular
area at left indicates moisture inside a wall. Image
credit: Intelligent Automation Inc.
For a high resolution version of this image contact Gail
Waves Help See Moisture Inside Walls
building community soon may have radio vision—a new
way to “see” moisture
inside walls. Building researchers at the National Institute
of Standards and Technology (NIST) have joined forces with
Intelligent Automation Inc. in Rockville, Md., to develop
a way to use ultra wide-band radio waves to non-destructively
detect moisture within the walls of a building. As any homeowner
who’s suffered with leaky plumbing or mold problems
will tell you, the current state of the art for pinpointing
moisture problem areas relies mostly on guesswork and a drywall
on hardware developed by Intelligent Automation, the new
NIST technique involves sending a broad range of
frequencies through typical drywall construction to look
for a “moisture” signature in the signal that
is reflected back. Laboratory experiments conducted with
a simplified wall section made of gypsum board, fiberglass
insulation, and oriented strand board (similar to plywood),
demonstrated that the new method can locate moisture pockets
to within one centimeter.
of water within the model wall produced a stronger reflection
of radio waves at specific frequencies.
time between transmission of the waves and their arrival
at a receiving antenna helps determine the location of
the water. By processing the reflected signals with computer
software, the researchers can create detailed three-dimensional
maps that highlight wet areas.
is continuing to see how well the apparatus performs with
real walls that
include studs, wires, pipes
that may complicate the readings. A paper
describing the research has been accepted for publication
in an upcoming issue of ASHRAE Transactions.
Brighten for Future Superconductor Power Cables
research from the National Institute of Standards and Technology
(NIST) suggests that next-generation, high-temperature superconductor
(HTS) wire can withstand more mechanical strain than originally
thought. As a result, superconductor power cables employing
this future wire may be used for transmission grid applications.
Projected to become available in three to four years, the advanced
superconductor wire (known in the industry as second generation
HTS wire) is expected to cost less than the HTS wire used in
superconductor power cables. The NIST research is described in
the Nov. 17 issue of Applied Physics Letters.
power cables can carry three to five times the power of conventional
copper cables. Compact, underground superconductor
cables can be used to expand capacity and direct power flows
at strategic points on the electric power grid and can be used
in city centers where there is enormous demand, but little
space under the streets for additional copper cables. One important
challenge in using this next-generation HTS wire in such applications
is the need for sufficient strength and resiliency to withstand
the stretching and bending
that occurs during power cable fabrication and installation.
superconductor ceramic coatings on metallic substrates fabricated
by American Superconductor Corp. and Oak Ridge National
Laboratory, the NIST researchers tested the material’s
electromechanical properties. According to lead author Najib
Cheggour, they found that these advanced wires could stretch
almost twice as much as previously believed without any cracking
of the superconductor coating and with almost no loss in the
coating’s ability to carry electricity.
the NIST team found that strain-induced degradation of the
superconductors’ ability to carry electricity
is reversible up to a certain critical strain value. That
is, the materials return to their original condition once the
is relieved. The strain tolerance of this future HTS wire
was found to be high enough for even the most demanding electric
utility applications. The discovered reversible strain effect
also opens new opportunities for better understanding of
mechanisms governing the conduction of electricity in this
class of superconductors.
CD-ROM Provides Mass Metrology Training
and measures are critical for commerce in everything from
animal feed to gasoline. The National Institute of
Standards and Technology (NIST) trains many state and industry
laboratory metrologists who verify the accuracy of standards
used to test the measuring equipment used in commercial
transactions. To alleviate a training backlog of officials
from government and industrial mass calibration laboratories,
NIST has just released an electronic mass measurement training
years in the making, the free multimedia CD-ROM covers
NIST’s basic one-week mass metrology courses. It
includes interactive activities, knowledge quizzes, examples,
and specialty graphics and photos for specific products.
The CD-ROM is designed to introduce mass metrology to newcomers
to the field; offer supplementary training for those
who have recently
attended a metrology course and want to review their knowledge
before entering the laboratory environment; and act as a
refresher for long-time laboratory staff unfamiliar with
the latest measuring
Basic Mass Metrology CD-ROM (NIST Special Publication 1001)
is available from NIST at (301) 975-4004
or by e-mail at email@example.com.
A Spanish version of the CD-ROM is under development.
John Blair, (301) 975-4261
RNA—Quantitative measurements of RNA for
gene expression assays give information about what genes
are “turned on,” or being expressed, in a cell.
What genes are being expressed, and when, gives key information
about what proteins are being made and leads to conclusions
about the biological function. NIST is hosting a workshop
on Dec. 2 to invite comments and discussion on a new specification
for materials used to validate measurements of RNA.
details see http://www.cstl.nist.gov/biotech/workshops/ERCC2003/.