At the forefront of biomedical
research, medical scientists use
particle accelerators to explore
the structure of biological
molecules. They use the energy
that charged particles emit when
accelerated to nearly the speed
of light to create one of the
brightest lights on earth, 30 times
more powerful than the sun and
focused on a pinpoint.
Deciphering the structure of
proteins is key to understanding biological processes and healing
disease. To determine a protein's structure, researchers direct the
beam from an accelerator called a synchrotron through a protein
crystal. The crystal scatters the beam onto a detector. From the
pattern of scattering, computers calculate the position of every atom
in the protein molecule and create a 3-D image of the molecule.
Physicists originally built synchrotron accelerators to explore the
fundamental nature of matter. At first, they looked on synchrotron
radiation as a troublesome problem that sapped electrons'
acceleration energy. However, they soon saw the potential to use
this "nuisance" energy to create ultrapowerful beams to study
biological molecules and other materials.
Now, researchers at synchrotron light sources use dedicated particle
accelerators to explore the molecules of life with matchless power
and precision. Future accelerators will create still higher-energy
beams for both particle physics and biomedicine.
An undulator, in use at the Advanced Light
Source at DOE's Lawrence Berkeley National
Laboratory. Each undulator contains two
4.55-meter-long arrays of permanent magnets
with alternating polarity.The arrays are
supported by a superstructure capable of
resisting the force of their attractionˇup to 42
tons (the weight of a 38,000 kg mass). As an
electron beam passes through a vacuum
chamber between the arrays, the magnets
cause the beam to curve back and forth and
thus to produce synchrotron radiation. Undulators produce light
brighter than that from other types of synchrotron radiation sources,
with the added characteristics of partial coherence and linear
polarization. In this photograph, a strobe light emulates the electron
Diffraction image of a biomolecule. Beams from a
synchrotron light source pass through crystals of
protein to create images like this one. Using this
diffraction technique, scientists can use light
sources from particle accelerators to decode the
internal structure of complex protein molecules such
Researchers using a
beamline at the Advanced
Photon Source at DOE's
Argonne National Laboratory
have discovered clues that
promise a better
understanding of the prevention of juvenile diabetes. Here, an insulin
molecule binds to a human glycoprotein found at the cell surface.
The Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.