Science Highlights 2000
Science highlights of research occuring at the APS.
Materials Analysis
using New X-ray Microbeams (Oct. 17)
Materials ranging from massive steel girders
to the microscopic aluminum wires in computer chips are made of
grains-tiny crystals with diameters measured in millionths of a
meter (microns). If scientists could "see" these individual
grains, they could determine their orientation, as well as the
effects of stress and chemical activity on them. They might also
be able to determine how to make circuits in microelectronic components
smaller and faster and find out to what extent grains of a superconducting
material mimic the alignment of the substrate on which the material
is grown, which is essential to the design of effective high-temperature
superconductors. Scientists are now able to study the fine details
of grain behavior in materials, thanks to new x-ray beamlines at
the Advanced Photon Source (APS). Oak Ridge National Laboratory
(ORNL) is a leader in efforts to develop microbeams at the APS.
(pdf) (html)
Setting the Standard
for Atomic-Scale Measurements (Oct. 11)
X-ray beams from the Advanced Photon Source and
the Elektronen-Synchrotron (DESY) in Hamburg have been used to set
a potential new standard of length for short distances, based on
radiation from the excited nuclei of iron atoms. Further improvements
may make this standard an important tool for probing the structure
of matter, where physicists must gauge the separations between nuclei
with an accuracy of millionths of an angstrom.
(pdf) (html)
Using X-ray Beams
to Study Indirect Flight Muscle from Drosophila Melanogaster (Oct. 11)
Researchers have applied high-brilliance x-ray
beams from the Bio-CAT undulator insertion-device beamline at the
Advanced Photon Source to small-angle x-ray diffraction and obtained
high-quality, <i>in vivo</i> patterns from the flight
muscles of live fruit flies (Drosophila melanogaster).
This new experimental system facilitates investigation of the relation
between molecular structure and muscle function in living organisms.
(pdf) (html)
Structure of the Fc
Fragment of Human IgE Bound to Its Receptor (Oct. 3)
Researchers
from Northwestern University and the Harvard Medical School
have identified the structure of the interaction complex of two
molecules, the antibody immunoglobin-E (IgE) and its high-affinity
receptor, that are central to the allergic response in humans.
This work was carried out APS beamline 5-ID, which is operated
by the E.I. Du pont de Nemours &
Co.-Northwestern University-The Dow Chemical Company Collaborative
Access Team.
(pdf) (html)
APS-based Technologies
Garner Three R&D-100 Awards (Sept. 29)
Three technologies developed for use at APS
have won R&D 100 awards for the year 2000. The awards are given
annually by R&D Magazine to the 100 most significant technical
products of the year.
(pdf) (html)
Charge
Melting & Polaron
Collapse in LA1.2SR1.8MN207 (Jun. 28)
Recent studies carried out on the Synchrotron
Radiation Instrumentation Collaborative Access Team's beamline
1-ID-C at the Advanced Photon Source provide important new insights
into the relation of polarons to collossal magnetoresistance
(CMR), which is of great interest to both basic science, which
has led to CMR discoveries such as charge and orbital ordering,
and applied science, where the potential for technological applications
is significant.
(pdf) (html)
The Mystery of Ioannes
Bos: The Metal Speaks - X-Ray Studies of Astrolabes (Jun. 28)
Using a focused,
monochromatic beam of high-photon-energy x-rays from the Synchrotron
Radiation Instrumentation Collaborative Access Team beamline 1-BM at
the Advanced Photon Source, researchers performed metallurgical analyses
on two astrolabes: M-33a (Adler Planetarium, from the Mensing
Collection), and DW0595 (Harvard University, from the David P. Wheatland
Collection). These
instruments are both signed "Ioannes
Bos, 24 March 1597." Results indicate that the composition and
microstructure of the main components of M-33a are consistent with
the 1597 date, while those of DW0595 reveal a much more recent origin.
(pdf) (html)
