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
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
Fusion Science and Technology
Latest News
ANS joins others in seeking to discuss SNF/HLW impasse
The American Nuclear Society joined seven other organizations to send a letter to Energy Secretary Christopher Wright on July 8, asking to meet with him to discuss “the restoration of a highly functioning program to meet DOE’s legal responsibility to manage and dispose of the nation’s commercial and legacy defense spent nuclear fuel (SNF) and high-level radioactive waste (HLW).”
Takashi Nakamura, Masahiko Fujii, Kazuo Shin
Nuclear Science and Engineering | Volume 83 | Number 4 | April 1983 | Pages 444-458
Technical Paper | doi.org/10.13182/NSE83-A18648
Articles are hosted by Taylor and Francis Online.
The energy spectra of neutrons emitted by thick targets of carbon, iron, copper, and lead at angles of 0, 15, 30, 45, 75, and 135 deg to the incident beam of 30- and 52-MeV protons were obtained by unfolding the pulse height distributions measured with an NE-213 scintillator. The angular distribution of neutrons above 3 or 4 MeV was obtained by integrating the measured spectra. The measured spectra were compared with a Monte Carlo calculation based on the Fermi free gas model of intranuclear cascades and evaporation. This comparison revealed that the calculated spectra are harder and stronger in the forward direction, but softer and weaker in the backward direction than are the experimental spectra. There is good agreement between the two at ∼75 deg. This experimental result showed that the calculational model is not adequate in the energy region below ∼100 MeV, where nuclear structure has a great influence on neutron production. The total neutron yield was obtained by estimating the neutron yield below a few million electron volts by fitting the spectra measured above that energy to the Maxwellian distribution and showed good agreement with other experimental results.