@article{miller_holmes_gardner_2015, title={An analytical approach for treating background in spectral analysis measurements}, volume={116}, ISSN={["0969-806X"]}, DOI={10.1016/j.radphyschem.2015.01.018}, abstractNote={A method of determining the spectral shape of background radiation present in experimental spectra via a mathematical approach is presented. Elements of interest will be subtracted from an experimental spectrum using the linear correlation coefficient across a characteristic peak to determine their contribution. Once all elements of interest are removed, the remainder of the experimental spectrum should represent an approximation of the background. This approximation can then be used in conjunction with library least-squares to determine the background and elemental contributions to the unknown spectrum.}, journal={RADIATION PHYSICS AND CHEMISTRY}, author={Miller, Ian and Holmes, Thomas W. and Gardner, Robin P.}, year={2015}, month={Nov}, pages={87–91} }
 @article{lee_holmes_calderon_gardner_2012, title={Molecular Dynamics simulation for PBR pebble tracking simulation via a random walk approach using Monte Carlo simulation}, volume={70}, ISSN={["0969-8043"]}, DOI={10.1016/j.apradiso.2011.11.043}, abstractNote={Using a Monte Carlo (MC) simulation, random walks were used for pebble tracking in a two-dimensional geometry in the presence of a biased gravity field. We investigated the effect of viscosity damping in the presence of random Gaussian fluctuations. The particle tracks were generated by Molecular Dynamics (MD) simulation for a Pebble Bed Reactor. The MD simulations were conducted in the interaction of noncohesive Hertz–Mindlin theory where the random walk MC simulation has a correlation with the MD simulation. This treatment can easily be extended to include the generation of transient gamma-ray spectra from a single pebble that contains a radioactive tracer. Then the inverse analysis thereof could be made to determine the uncertainty of the realistic measurement of transient positions of that pebble by any given radiation detection system designed for that purpose.}, number={5}, journal={APPLIED RADIATION AND ISOTOPES}, author={Lee, Kyoung O. and Holmes, Thomas W. and Calderon, Adan F. and Gardner, Robin P.}, year={2012}, month={May}, pages={827–830} }
 @article{holmes_calderon_peeples_gardner_2011, title={A proposed benchmark problem for cargo nuclear threat monitoring}, volume={652}, ISSN={["0168-9002"]}, DOI={10.1016/j.nima.2010.10.070}, abstractNote={There is currently a great deal of technical and political effort focused on reducing the risk of potential attacks on the United States involving radiological dispersal devices or nuclear weapons. This paper proposes a benchmark problem for gamma-ray and X-ray cargo monitoring with results calculated using MCNP5, v1.51. The primary goal is to provide a benchmark problem that will allow researchers in this area to evaluate Monte Carlo models for both speed and accuracy in both forward and inverse calculational codes and approaches for nuclear security applications. A previous benchmark problem was developed by one of the authors (RPG) for two similar oil well logging problems (Gardner and Verghese, 1991, [1]). One of those benchmarks has recently been used by at least two researchers in the nuclear threat area to evaluate the speed and accuracy of Monte Carlo codes combined with variance reduction techniques. This apparent need has prompted us to design this benchmark problem specifically for the nuclear threat researcher. This benchmark consists of conceptual design and preliminary calculational results using gamma‐ray interactions on a system containing three thicknesses of three different shielding materials. A point source is placed inside the three materials lead, aluminum, and plywood. The first two materials are in right circular cylindrical form while the third is a cube. The entire system rests on a sufficiently thick lead base so as to reduce undesired scattering events. The configuration was arranged in such a manner that as gamma-ray moves from the source outward it first passes through the lead circular cylinder, then the aluminum circular cylinder, and finally the wooden cube before reaching the detector. A 2 in.×4 in.×16 in. box style NaI (Tl) detector was placed 1 m from the point source located in the center with the 4 in.×16 in. side facing the system. The two sources used in the benchmark are 137Cs and 235U.}, number={1}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Holmes, Thomas Wesley and Calderon, Adan and Peeples, Cody R. and Gardner, Robin P.}, year={2011}, month={Oct}, pages={52–57} }