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
2026 Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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
Dec 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
December 2025
Nuclear Technology
Fusion Science and Technology
November 2025
Latest News
NEUP honors young ANS members with R&D awards
Each year, the Department of Energy’s Nuclear Energy University Program (NEUP) recognizes graduate and undergraduate students for their innovative nuclear energy research. The winners of the Innovations in Nuclear Energy Research and Development Student Competition (INSC) receive honoraria along with travel and conference opportunities, including the chance to present their publications at the annual American Nuclear Society Winter Conference & Expo.
Marshall F. Crouch
Nuclear Science and Engineering | Volume 2 | Number 5 | September 1957 | Pages 631-639
Technical Paper | doi.org/10.13182/NSE57-A25430
Articles are hosted by Taylor and Francis Online.
Fast neutrons are produced inside a water moderator by a Po-α-Be source used effectively as a pulsed neutron source. The slowing-down time to the Cd edge is measured with a BF3 proportional counter used with a cadmium difference technique. The mean slowing down time to O.35 ev, and the variance thereof, are found to be 5.2 µsec and 8.0 µsec2, respectively. It is shown that this is in reasonable agreement with the results of a Monte Carlo calculation, provided collisions are considered to involve whole H2O molecules when the neutron energy falls below about 1.6 ev.
