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Division Spotlight
Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
Meeting 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!
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A look inside NIST’s work to optimize cancer treatment and radiation dosimetry
In an article just published by the Taking Measure blog of the National Institute of Standards and Technology, Stephen Russek—who leads the Imaging Physics Project in the Magnetic Imaging Group at NIST and codirects the MRI Biomarker Measurement Service—describes his team’s work using phantom stand-ins for human tissue.
M. M. R. Williams, Edward W. Larsen
Nuclear Science and Engineering | Volume 139 | Number 1 | September 2001 | Pages 66-77
Technical Paper | doi.org/10.13182/NSE01-A2222
Articles are hosted by Taylor and Francis Online.
The majority of earlier work on neutron transport in spatially random media has relied on special models of the random process, closure techniques or perturbation theory. The purpose of the present paper is to further develop a technique, which employs the source-sink method and simulation, and which in principle leads to exact probability distributions, to assess the accuracy of such approximate methods. To this end, we also use perturbation theory, and extend it to eigenvalue problems thereby enabling random fluctuations in reactivity to be studied and some measures of their statistical properties to be calculated. We have found, by comparing results for the variance in the reactivity fluctuations with essentially exact values, that the perturbation method is an accurate way to deal with stochastic equations and is far more efficient numerically than the more exact simulation method.