Argonne at 50

Argonne's super light source casts a long shadow

ARGONNE, Ill. (June 4, 1996) -- When a group of scientists and politicians gathered at Argonne National Laboratory on June 4, 1990, to break ground for a world-class, 7-billion electron-volt X-ray source, the event cast a shadow both forward and backward in time.

Looking forward, the 1990 groundbreaking preceded by nearly five years a scientific milestone that occurred on March 26, 1995, and launched a new era in American research. At 7:13 a.m. on that date, Argonne scientists and engineers generated the "first light" from the newly constructed Advanced Photon Source, which now produces the nation's brightest beams of X-rays available for research.

Looking back, the groundbreaking also represented a continuing series of advances in X-ray research that began in 1895, when Wilhelm Roentgen discovered this unusual new form of radiation. While studying the rays, Roentgen quickly found that he could photograph balance-weights in a closed box, the chamber of a shotgun and the bones in his wife's hand.

Since then, X-rays have been ideal for revealing what visible light can't -- for seeing past "impossible" barriers.

The medical uses of X-rays are familiar to anyone who has spent time in a hospital or a dentist's office; but in the last century, scientists have come to depend on X-rays to reveal many other hidden details of the world around and within us. They have learned how to use the radiation to probe amazing intricacies: the atomic structure of biological molecules such as proteins and DNA, the chemical reactions and processes that occur as polymers and ceramics form, and even the detailed crystalline structure of most elements.

X-rays are a form of electromagnetic radiation, very similar to the light that our eyes can see. X-rays have wavelengths much shorter than visible light. These shorter wavelengths can penetrate into and distinguish the details visible light can't, just as a sharp probe can fit into and reveal information about smaller shapes than a blunt one. This property makes X-rays uniquely useful in probing the sub-microscopic world around us.

The APS produces X-rays with extremely short wavelengths, smaller than the size of an atom. In addition, the beams from the facility are 10,000 times more brilliant than any previously available.

Brighter light reveals more details in structure and allows faster image-taking. A photographer attempting to photograph in dim light uses a slow shutter speed to allow time for more light to reach the photographic film. In bright light, much faster shutter speeds are possible, producing sharper images that can freeze rapid actions.

With such fast picture-taking abilities, scientists hope they will even be able to make motion pictures of chemical processes in action. These "microscopic movies" will capture images of the intermediate arrangements of atoms and molecules as they react with one another and change shape.

Biological and medical researchers hope the movies will allow them to see the movements of every atom in an enzyme as it catalyzes a chemical reaction. Enzymes help control most of the chemical reactions that take place in the human body.

Such studies will not only increase science's knowledge of basic biochemical processes such as photosynthesis, DNA replication and protein synthesis, but will also help molecular biologists design "smart" pharmaceuticals that can modify the actions of specific enzymes.

Researchers from Du Pont and Dow plan to use the APS to study how nylon and other synthetic fibers form during the spinning process. The structure of the fibers determines important properties such as its strength and flexibility and even the way the material takes up dye.

Discoveries made at the APS are expected to enhance the quality of daily life and benefit the nation's economic and technological future. Advances are predicted particularly in biotechnology, polymers and advanced materials, medical diagnostics, digital imaging techniques, semiconductor materials and microelectronic circuits.

The photograph of Bertha Roentgen's hand was only the beginning. The APS is sure to reveal the hidden structure of the world around us in ways Wilhelm Roentgen and his successors in X-ray research could never have expected.

For more information, please contact Catherine Foster (630/252-5580 or cfoster@anl.gov) at Argonne.