@article{wang_wang_peeples_yu_gardner_2012, title={Development of a simple detector response function generation program: The CEARDRFs code}, volume={70}, ISSN={["0969-8043"]}, DOI={10.1016/j.apradiso.2011.11.003}, abstractNote={A simple Monte Carlo program named CEARDRFs has been developed to generate very accurate detector response functions (DRFs) for scintillation detectors. It utilizes relatively rigorous gamma-ray transport with simple electron transport, and accounts for two phenomena that have rarely been treated: scintillator non-linearity and the variable flat continuum part of the DRF. It has been proven that these physics and treatments work well for 3×3″ and 6×6″ cylindrical NaI detector in CEAR's previous work. Now this approach has been expanded to cover more scintillation detectors with various common shapes and sizes. Benchmark experiments of 2×2″ cylindrical BGO detector and 2×4×16″ rectangular NaI detector have been carried out at CEAR with various radiactive sources. The simulation results of CEARDRFs have also been compared with MCNP5 calculations. The benchmark and comparison show that CEARDRFs can generate very accurate DRFs (more accurate than MCNP5) at a very fast speed (hundred times faster than MCNP5). The use of this program can significantly increase the accuracy of applications relying on detector spectroscopy like prompt gamma-ray neutron activation analysis, X-ray fluorescence analysis, oil well logging and homeland security.}, number={7}, journal={APPLIED RADIATION AND ISOTOPES}, author={Wang, Jiaxin and Wang, Zhijian and Peeples, Johanna and Yu, Huawei and Gardner, Robin P.}, year={2012}, month={Jul}, pages={1166–1174} }
 @article{peeples_gardner_2012, title={Monte Carlo simulation of the nonlinear full peak energy responses for gamma-ray scintillation detectors}, volume={70}, ISSN={["0969-8043"]}, DOI={10.1016/j.apradiso.2011.12.006}, abstractNote={A Monte Carlo code has been developed, which predicts the nonlinear full peak energy responses of scintillation detectors to incident gamma-rays. It is illustrated here for the popular scintillation detectors, NaI and BGO. The full energy response can be determined by treating the detector as effectively infinite and assuming that all photons and electrons are fully absorbed within the detector. This assumption means that no geometrical direction or position tracking is required, only the selection of sequential photon interactions based on the appropriate energy-dependent interaction cross-sections. The full energy pulse-height response is determined by the sum of the pulse-height responses from all secondary electrons. Results from infinite NaI and BGO detectors indicate that even though the maximum difference in electron scintillation efficiency is about the same for the two scintillation detectors, the overall effect on the extent of the difference in pulse height is much less for BGO than NaI. This result is due to the larger density and effective atomic number of BGO, which causes significantly fewer Compton scattering events. Compton scattering interactions reduce the incident photon energy without absorption and therefore give more responses at reduced energy where the electron scintillation efficiency is most different.}, number={7}, journal={APPLIED RADIATION AND ISOTOPES}, author={Peeples, Johanna L. and Gardner, Robin P.}, year={2012}, month={Jul}, pages={1058–1062} }
 @article{peeples_stokely_michael doster_2011, title={Thermal performance of batch boiling water targets for 18F production}, volume={69}, ISSN={0969-8043}, url={http://dx.doi.org/10.1016/j.apradiso.2011.06.015}, DOI={10.1016/j.apradiso.2011.06.015}, abstractNote={Batch boiling targets are commonly used in cyclotrons to produce Fluorine-18 by proton bombardment of Oxygen-18 enriched water. Computational models have been developed to predict the thermal performance of bottom-pressurized batch boiling production targets. The models have been validated with experimental test data from the Duke University Medical Cyclotron and the Wisconsin Medical Cyclotron. Good agreement has been observed between experimental measurements and model predictions of average target vapor fraction as a function of beam current and energy.}, number={10}, journal={Applied Radiation and Isotopes}, publisher={Elsevier BV}, author={Peeples, Johanna L. and Stokely, Matthew H. and Michael Doster, J.}, year={2011}, month={Oct}, pages={1349–1354} }
 @article{gardner_ai_peeples_wang_lee_peeples_calderon_2011, title={Use of an iterative convolution approach for qualitative and quantitative peak analysis in low resolution gamma-ray spectra}, volume={652}, ISSN={["0168-9002"]}, DOI={10.1016/j.nima.2010.12.224}, abstractNote={In many applications, low resolution gamma-ray spectrometers, such as sodium iodide scintillation detectors, are widely used primarily due to their relatively low cost and high detection efficiency. There is widespread interest in improved methods for analyzing spectral data acquired with such devices, using inverse analysis. Peak means and peak areas in gamma- and X-ray spectra are needed for both qualitative and quantitative analysis. This paper introduces the PEAKSI code package that was developed at the Center for Engineering Applications of Radioisotopes (CEAR). The basic approach described here is to use accurate forward models and iterative convolution instead of direct deconvolution. Rather than smoothing and differentiation a combination of linear regression and non-linear searching is used to minimize the reduced chi-square, since this approach retains the capability of establishing uncertainties in the estimated peak parameters. The PEAKSI package uses a Levenberg–Marquardt (LM) non-linear search method combined with multiple linear regression (MLR) to minimize the reduced chi-square value for fitting single or multiple overlapping peaks to determine peak parameters, including peak means, peak standard deviations or full width at half maximum (FWHM), net peak counts, and background counts of peaks in experimental gamma-ray spectra. This approach maintains the natural error structure so that parameter uncertainties can be estimated. The plan is to release this code to the public in the near future.}, number={1}, journal={NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT}, author={Gardner, Robin P. and Ai, Xianyun and Peeples, Cody R. and Wang, Jiaxin and Lee, Kyoung and Peeples, Johanna L. and Calderon, Adan}, year={2011}, month={Oct}, pages={544–549} }