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
Decommissioning & Environmental Sciences
The mission of the Decommissioning and Environmental Sciences (DES) Division is to promote the development and use of those skills and technologies associated with the use of nuclear energy and the optimal management and stewardship of the environment, sustainable development, decommissioning, remediation, reutilization, and long-term surveillance and maintenance of nuclear-related installations, and sites. The target audience for this effort is the membership of the Division, the Society, and the public at large.
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.”
H. G. Kaper
Nuclear Science and Engineering | Volume 28 | Number 3 | June 1967 | Pages 415-425
Technical Paper | doi.org/10.13182/NSE67-A28956
Articles are hosted by Taylor and Francis Online.
An approximate theory for the slowing down of neutrons in a nonmultiplying medium with plane symmetry is described. The theory is based on an approximate form of the transfer function for elastic scattering under the hypothesis that the mass number of the moderator is larger than one. In the A−N approximation the slowing down equation is reduced to a finite system of differential equations with respect to the lethargy variable. A detailed study has been made of the results obtained in the A−N approximation with N = 0 and N = 1. Special attention has been paid to a comparison of the A−1 approximation with age theory and asymptotic theory.
