ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
Standards Program
The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
R. Ofek, M. Segev
Nuclear Science and Engineering | Volume 111 | Number 4 | August 1992 | Pages 319-344
Technical Paper | doi.org/10.13182/NSE92-A15482
Articles are hosted by Taylor and Francis Online.
An approach is summarized for developing a full analytical method for the generation of laboratory (lab) coordinate system multigroup transfer cross sections of elastic and discrete-level inelastic scatterings of neutrons, where the angular distribution data of the scattered neutrons are given as coefficients of truncated Legendre polynomial expansions in the center-of-mass (c.m.) coordinate system. In the “kernel form”of the multigroup approximation, fluxes, cross sections, and angular data are left outside the integration signs of the transfer cross-section expression. Then, the integrand is a four-index kernel- the source and sink energy groups and the Legendre polynomials in the c.m. and lab systems each contributing one index—integrated over the source and sink groups. In the method introduced, the double integration on the neutron pre- and postscattering energies, in these two groups, is carried out analytically. This is done by decomposing the Legendre polynomials in the integrand into their representations as polynomials of their arguments—the cosines of the angle of scattering in the lab and the c.m. systems. It is assumed that the flux is presented as a simple function of the neutron prescattering energy. The first integration takes place between the cosines of scattering in the c.m. system related by the kinematics of scattering to the energy boundaries of the sink group, while the second integration takes place between the energy boundaries of the source group. Transfer cross sections of discrete-level inelastic scatterings are evaluated quite similarly to those of elastic scatterings. The only difference is in the integration over the prescattering energies, which stems from the replacement of the mass number of the scattering nucleus, appearing in the expression for the cosine of scattering in the lab system, by an energy-dependent “effective mass number ”in the case of inelastic scattering. The method of evaluation described seems to be fast and accurate and is valid theoretically up to any order of Legendre expansions desired. Some evaluations made with this method, for both elastic and discrete-level inelastic scatterings, are compared with numerical computations carried out by other methods: the NJOY cross-section processing code and the method outlined by Hong and Shultis. The flux used as a weighting function is either energy independent or of a 1/E’ form (where E’ is the prescattering energy of the neutron). The results are in good agreement.