Obituary of Alan Smith (1924-2012)

Alan Bowen Smith was employed at Argonne National Laboratory for his entire active career from 1953 to 1992. Thereafter, he served in an emeritus status until his death. His field of research was applied nuclear physics, with a focus on measurement and nuclear model analyses of fast-neutron total, elastic-scattering, and inelastic-scattering cross sections in support of the development of the neutron optical model.

Alan Bowen Smith, an eminent physicist in the field of nuclear data, died on 5 January 2012 at age 87. Alan is best known professionally for his work on the neutron optical model. His studies in this field involved measurements and theoretical analyses of neutron total, elastic-scattering, and inelastic-scattering interactions in the fast-neutron energy region that encompassed virtually the entire range of the Chart of the Nuclides. Following combat duty in the U.S. Army during WWII, Alan earned a B.A. degree at Beloit College (Wisconsin) and M.S. and Ph.D. degrees at Indiana University (Bloomington). In 1953 he joined Argonne National Laboratory where he spent his entire career, first as a scientific staff member until 1992 (when he formally retired) and subsequently as an emeritus scientist. He led the Applied Nuclear Physics Section, a research group dedicated to experimental and theoretical work on fast-neutron nuclear reactions, for several decades. Alan recognized early in his career the importance of neutron physics to many areas of nuclear technology. Furthermore, he understood that while experiments are important they cannot by themselves provide all the nuclear data needed for applications, e.g., for the design of nuclear reactors. Therefore, he focused his talents and energy on development of the neutron optical model since he reasoned correctly that all neutron-induced nuclear-reaction calculations begin with consideration of the neutron optical potential. While global optical models can offer a qualitative picture of the interaction of neutrons with nuclear matter, one must have information about the local optical-model potentials, which are influenced by nuclear spin, structure, and deformation effects, to achieve the computational accuracy needed for applications. Alan spent nearly four decades performing measurements and undertaking analyses of neutron total, elastic-scattering, and inelastic-scattering cross-section and angular distribution data obtained using a multi-angle, time-of-flight neutron spectrometer that he designed and constructed. These experiments employed a wide range of scattering samples comprised of both stable and radioactive elements; many of these samples were isotopically-enriched. The investigations were undertaken at lower energies (below 1.5 MeV) in the 1960’s using a small Van de Graaff accelerator, and later at higher energies (from 1.5 to 10 MeV) at the ANL Dynamitron (1970 to 1992). Alan firmly believed that no nuclear-data experimental investigation could be considered completed until the results from measurements had been interpreted in the context of contemporary nuclear theories and formally published. He reported the results of his work extensively in the open literature. His publication list exceeds 500 contributions that appear in prestigious journals in the U.S. and abroad. In addition he produced copious detailed technical reports and contributed extensively to scientific conference proceedings. Finally, he contributed to the development of evaluated nuclear data libraries used for applications. Alan held the conviction that nuclear data should serve the needs of society, so throughout the course of his career he actively consulted with and collaborated with applied users of nuclear data in those areas of nuclear technology where numerical data play important roles. In addition to his scientific work, Alan contributed his energy and good judgment within the nuclear science community through numerous advisory and consulting positions. He served as Visiting Professor in the Department of Nuclear and Energy Engineering at the University of Arizona (1993-1998). He was an early leader in the nuclear data activities of the OECD Nuclear Energy Agency (Paris, France) and the International Atomic Energy Agency (Vienna, Austria). Alan was also one of the founders (in 1966) of the Cross Section Evaluation Working Group (CSEWG), that organization responsible for production and stewardship of the U.S. Evaluated Nuclear Data Library (ENDF/B). He staunchly supported the activities of the National Nuclear Data Center at Brookhaven National Laboratory and served on its advisory board for many years. Alan was also involved with various AEC, ERDA, and DOE advisory groups as well as with an advisory committee to the Center for Radiation Research at NIST. Alan was universally respected and admired by those who knew him and are familiar with his accomplishments. In recognition of his body of scientific work and many other contributions to his field, Alan was honored with fellowship appointments in both the American Physical Society and the American Nuclear Society. He was also a recipient of the University of Chicago Distinguished Service Award. Above all, he was a friend, colleague, and valued mentor to three generations of nuclear scientists. His loss is not only a personal one for those who knew him well but unquestionably represents a loss for nuclear science as well.