Physics Nobel for neutron-scattering work.Two veterans of the early atomic age atomic age also Atomic Age n. The current era as characterized by the discovery, technological applications, and sociopolitical consequences of nuclear energy. earned the 1994 Nobel Prize in Physics The Nobel Prize in Physics (Swedish: Nobelpriset i fysik) is awarded once a year by the Royal Swedish Academy of Sciences. It is one of the six Nobel Prizes. The first prize was awarded in 1901. , announced last week. They won the honor for their pioneering and independent contributions some four decades ago to the development of neutron-scattering techniques for studying solids and liquids. As electrically neutral particles, neutrons can penetrate deeply into matter. Unlike X rays, they can readily evade a material's electrons to interact directly with atomic nuclei. These interactions produce changes in the direction and speed of the incoming neutrons. From these data, researchers can deduce the atomic structure of solids and determine the vibrations that typically shake these materials. Discovered in 1932, neutrons became available for research purposes shortly after World War II. The construction of a number of relatively simple, inexpensive nuclear reactors provided several sources of neutron beams, which scientists could direct at samples of various materials. Clifford G. Shull, now retired from the Massachusetts Institute of Technology Massachusetts Institute of Technology, at Cambridge; coeducational; chartered 1861, opened 1865 in Boston, moved 1916. It has long been recognized as an outstanding technological institute and its Sloan School of Management has notable programs in business, , was then at Oak Ridge Oak Ridge, city (1990 pop. 27,310), Anderson and Roane counties, E Tenn., on Black Oak Ridge and the Clinch River; founded by the U.S. government 1942, inc. as an independent city 1959. (Tenn.) National Laboratory. He and his coworkers used neutron beams to study the way simple crystals, such as sodium chloride sodium chloride, NaCl, common salt. Properties Sodium chloride is readily soluble in water and insoluble or only slightly soluble in most other liquids. It forms small, transparent, colorless to white cubic crystals. , deflect neutrons. These scattering experiments Scattering experiments (atoms and molecules) Experiments in which a beam of incident electrons, atoms, or molecules is deflected by collisions with an atom or molecule. provided the basis for determining the locations of different types of atoms in a wide range of materials. Neutron diffraction Neutron diffraction The phenomenon associated with the interference processes which occur when neutrons are scattered by the atoms within solids, liquids, and gases. techniques have since become particularly important for locating hydrogen atoms, which are practically invisible to X rays. Because neutrons are themselves tiny magnets, neutron-scattering techniques have also played a key role in elucidating the structure of magnetic materials. Bertram N. Brockhouse of McMaster University in Hamilton, Ontario, worked at the Chalk River (Ontario) Nuclear Laboratories, concentrating on neutron spectroscopy. Using neutrons of a particular energy to probe a material, he and his colleagues determined the energies of these neutrons as they emerged from the material. Energy losses could be attributed to the excitation of phonons -- collective movements of the atoms within the material. Nowadays, thousands of researchers worldwide rely on neutron-scattering techniques descended from those developed by Shull and Brockhouse to study materials ranging from polymers to superconductors. |
|
||||||||||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion