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.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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
Sep 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
October 2025
Nuclear Technology
September 2025
Fusion Science and Technology
Latest News
ANS and the U.K.’s NI announce reciprocal membership agreement
With President Trump on a state visit to the U.K., in part to sign a landmark new agreement on U.S.-U.K. nuclear collaboration, a flurry of transatlantic partnerships and deals bridging the countries’ nuclear sectors have been announced.
The American Nuclear Society is taking an active role in this bridge-building by forming a reciprocal membership agreement with the U.K.’s Nuclear Institute.
Sara A. Pozzi, Imre Pázsit
Nuclear Science and Engineering | Volume 153 | Number 1 | May 2006 | Pages 60-68
Technical Paper | doi.org/10.13182/NSE06-A2595
Articles are hosted by Taylor and Francis Online.
We propose a simple analytical model to describe the statistics of the number of collisions undergone by fast neutrons during slowing down until they are absorbed. We assume that the moderator is homogeneous and account for scattering and absorption, but we do not consider thermalization. Although the problem cannot be solved in a compact form, a simple recurrent formula provides the solution in a very transparent way. The model can be readily evaluated numerically, and the results are in excellent agreement with the corresponding Monte Carlo simulations. Both the mean number and the variance of the number of collisions are calculated. The results are discussed and compared with the classical case of neutron slowing down to or past a given energy in a moderating medium without absorption.