Albert V. Crewe, physicist, 1927-2009
Albert V. Crewe, who obtained the first images of atoms ever taken in an electron microscope, died Wednesday, Nov. 18, of complications from Parkinson's disease at his home in Dune Acres, Ind. He was 82.
In 1964 Crewe, a professor emeritus in physics at the University of Chicago and former director of Argonne National Laboratory, invented the scanning transmission electron microscope (STEM) based on a concept that came to him on an airplane trip. Crewe used focused beams of electrons instead of light waves for magnification. Because electron waves are thousands of times shorter than light waves, they can be used to resolve much smaller objects than can be seen through optical microscopes.
The technique involved scanning a beam of electrons across an object or specimen. The electrons scattered from the structure in the specimen were then used to generate an image on an oscilloscope, which converts electrical impulses into pictures, much like a television set.
In 1970 Crewe made headlines across the country when he used the instrument to obtain the first pictures of isolated atoms with an electron microscope. He imaged single uranium and thorium atoms magnified a million times. Crewe's STEM was able to view samples smaller than five angstroms-about the distance between atoms. Atoms measure approximately one angstrom, or four-billionths of an inch, in diameter. Because atoms are smaller than a light wave, it is impossible to see them through an optical microscope regardless of its power.
Crewe’s STEM achieved much higher resolution than existing electron microscopes of the day. “The reason is that Crewe for the first time used a field emission electron source, effectively a point source of electrons, much smaller and brighter than any other electron source,” said Riccardo Levi-Setti, Professor Emeritus in Physics at UChicago. “This enabled him to focus the scanning electron beam to a spot size of atomic dimensions. The field emission electron source is the key to his development.”
Levi-Setti followed in Crewe’s steps with the use of a field emission ion source, and was also able to focus an ion beam to a spot size smaller than anyone had ever obtained, by developing a high-resolution scanning ion probe or microscope, the key to high-resolution secondary ion mass spectrometry.
In 1976 Crewe made national headlines again with the first movies of atoms interacting with one another.Although images of individual atoms had been produced using a field ion microscope, there had been no way to reveal a single atom within a molecular structure. Crewe's STEM enabled researchers to study the arrangement of atoms in molecules to the benefit of many fields, including medicine, biochemistry and genetics.
Crewe was born Feb. 18, 1927, in Yorkshire, England. He received his bachelor's degree in 1947 in physics with highest honors and his Ph.D. in 1951 in physics, both from the University of Liverpool. His professor at Liverpool was Sir James Chadwick, who received the 1935 Nobel Prize in physics for discovering the neutron.
Crewe taught at the University of Liverpool from 1952 to 1955. At Liverpool he became the first scientist in the world to extract a continuous beam of "bullet" protons from a high-energy atom smasher. Before Crewe's achievement, proton bombardment experiments had to be carried out inside the vacuum chamber of an atom smasher, where space was limited and it was impractical to place detecting and recording equipment.
He became a research associate at the University of Chicago in 1955, and promptly succeeded in extracting a particle beam from the newly completed Cyclotron accelerator built by UChicago physicists Enrico Fermi and Herbert Anderson. Crewe became a member of the Physics Department faculty in 1956, attaining the rank of full professor in 1963. He was named the University's William E. Wrather Distinguished Service Professor in 1977, and retired as a professor emeritus in 1996.
Crewe also served in scientific leadership positions. He was director of Argonne National Laboratory's Particle Accelerator Division from 1958 to 1961. In this capacity he supervised the design and construction of Argonne's Zero Gradient Synchrotron. The $55 million project was completed in record time and operated successfully for 20 years.
He was director of Argonne National Laboratory from 1961 to 1967 and dean of the Physical Sciences Division at the University of Chicago from 1971 to 1981. As head of Argonne, he directed the work of 5,500 scientists and support staff and administered a budget of $100 million.
Crewe advocated the need for scientists to take the initiative in helping to solve societal problems in a speech published by Physics Today in 1967, reprinted in 2007. "Among the many possible issues that scientists could tackle, Crewe focused on pollution and crime-years before the first Earth Day and decades before the proliferation of televised forensic science," noted the editor.
And it was in his capacity as dean in 1973 that Crewe wrote an opinion piece for the New York Times, in which he criticized President Nixon for cutting funds for basic research while calling upon scientists to develop new sources of energy.
His awards include the Albert Michelson Medal from Philadelphia's Franklin Institute for his contributions to electron microscopy, the Distinguished Service Award from the Electron Microscopy Society of America, the Ernst Abbe Memorial Award from the New York Microscope Society, and the Duddell Medal from London's Institute of Physics for his development of the ultra-high resolution scanning transmission electron microscope.
He also was a member of the National Academy of Sciences and an honorary fellow of the Royal Microscope Society and the Electron Microscope Society of China. He was named the 1970 Man of the Year by Industrial Research Inc., and he received honorary degrees from the University of Liverpool and the University of Missouri, Columbia, among other institutions.
Crewe is survived by his wife of 60 years, the former Doreen Blunsdon, and four children-Jennifer, a publishing executive in New York City; Sarah, head coach of High Altitude Aquatics in Ruidoso, N.M.; Elizabeth, a home-schooler in LaGrange, Ill.; and David, an engineer in Sunnyvale, Calif.; and 10 grandchildren.
- Albert Crewe's Wikipedia biography
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