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 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Apr 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
May 2026
Nuclear Technology
February 2026
Fusion Science and Technology
Latest News
DTRA’s advancements in nuclear and radiological detection
A new, more complex nuclear age has begun. Echoing the tensions of the Cold War amid rapidly evolving nuclear and radiological threats, preparedness in the modern age is a contest of scientific innovation. The Research and Development Directorate (RD) at the Defense Threat Reduction Agency (DTRA) is charged with winning this contest.
Dermott E. Cullen
Nuclear Science and Engineering | Volume 55 | Number 4 | December 1974 | Pages 387-400
Technical Paper | doi.org/10.13182/NSE74-3
Articles are hosted by Taylor and Francis Online.
The probability table method, developed for Monte Carlo calculations in the region of unresolved neutron resonances, is demonstrated to be of general use in neutron transport studies since the Boltzmann equation involved can be derived and solved by analogy to multigroup methods. Since the resulting equations can be cast into a form identical to that of the multigroup equations, they can be solved by existing multigroup transport codes. From a set of probability tables and spatially independent, unshielded, neutron cross sections, the method yields correct selfshielding effects, such as equivalent, spatially dependent, multigroup cross sections. Extension of the method and the use of probability tables outside the unresolved region are discussed.