Bulletin of the American Physical Society
2011 Fall Meeting of the APS Division of Nuclear Physics
Volume 56, Number 12
Wednesday–Saturday, October 26–29, 2011; East Lansing, Michigan
Session NA: Mini-Symposium on Emerging Needs for Nuclear Data II |
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Chair: Boris Pritychenko, Brookhaven National Laboratory Room: 62 |
Saturday, October 29, 2011 10:30AM - 10:42AM |
NA.00001: STARLIB: A Next-Generation Reaction-Rate Library for Nuclear Astrophysics A.L. Sallaska, C. Iliadis, A.E. Champagne, F.X. Timmes, S. Starrfield One of the major inadequacies of current reaction-rate libraries is the absence of information on uncertainties. Although estimates have been attempted, these uncertainties are generally not based on rigorous statistical definitions. Clearly, a common standard for deriving uncertainties is warranted. STARLIB is a new, next-generation reaction-rate library that addresses this deficiency by providing a tabular, up-to-date database that supplies not only the recommended rate but also its factor uncertainty. The foundation of this library rests on an entirely new method for calculating reaction rates: Monte-Carlo simulation, which utilizes experimental nuclear physics quantities as inputs, yields a probability-density function for the reaction rate at a given temperature [1]. From the cumulative distribution of rate probability densities, the low, median, and high rates are naturally defined. In addition, quantities with upper limits are seamlessly included. This library attempts to bridge the gap between experimental nuclear physics data and stellar modelers by providing a convenient tabular format with reliable uncertainties for use in the simulation of astrophysical phenomena. We expect to submit STARLIB for publication by year's end, which will coincide with the unveiling of a webpage for ease of dissemination and updating.\\[0pt] [1] C. Iliadis {\it et al.}, Nucl. Phys., {\bf A841}, 31 (2010). [Preview Abstract] |
Saturday, October 29, 2011 10:42AM - 11:06AM |
NA.00002: Comments from DOE regarding Nuclear Data Ted Barnes In this presentation I will briefly discuss some present and future aspects of the Nuclear Data program from the perspective of the DOE Office of Nuclear Physics. [Preview Abstract] |
Saturday, October 29, 2011 11:06AM - 11:18AM |
NA.00003: Hadron Analyses Data Repository Online Project Michael Pennington The study of excited states of the nucleon is a major effort of present day nuclear physics. The spectrum reflects the internal dynamics of QCD. The past decade has seen a dramatic increase in the precision and range of experimental measurements from MAMI@Mainz and CEBAF@JLab. The analyses of these data, both in Europe and the US, have reached a level of robustness and sophistication that the results on the production of N*'s demand to be shared openly in the nuclear reaction community and beyond. Indeed, there is a demand for such information in fields beyond hadron spectroscopy, such as Heavy Ion collisions. Reaction calculations demand amplitudes and not just simple representations in terms of resonances. The aim of this project is to set up a publicly accessible database to archive (a) the full range of data on cross-sections and polarization asymmetries measured in hadro and photo-production of baryon resonances, (b) for each excited baryon its mass, width, couplings and transition formfactors, (c) for each analysis, the partial wave amplitudes with a detailed exposition of the methods used, (e) where appropriate these will be compared with the detailed predictions of QCD. [Preview Abstract] |
Saturday, October 29, 2011 11:18AM - 11:30AM |
NA.00004: GW Data Analysis Center and Database Development W.J. Briscoe, H. Haberzettl, M.W. Paris, I.I. Strakovsky, R.L. Workman The Data Analysis Center (DAC) of the Institute for Nuclear Studies (formerly the Center for Nuclear Studies) at The George Washington University houses the SAID facility. It constitutes a dedicated center that joins experimental, theoretical, and phenomenological efforts to support the national physics program for a variety of reactions of import to nucleon-resonance phenomena and nuclear physics generally. A renaissance in light-hadron spectroscopy is underway as a continuous stream of precision polarization data issues from existing and planned precision electromagnetic facilities, including the coming Jefferson Lab 12-GeV upgrade. Additionally, neutron-proton scattering, the \textit{primary standard} in measurements involving neutron-induced nuclear reactions, is under continual analysis and refinement. Through the ongoing maintenance of SAID, the DAC is making significant progress in its program to enhance and expand the partial-wave analyses of fundamental two- and three-body reactions (pion-nucleon, gamma-nucleon, and nucleon-nucleon) by maintaining and augmenting the analysis codes and databases associated with these reactions. These efforts provide guidance to experimental groups both nationally and internationally. [Preview Abstract] |
Saturday, October 29, 2011 11:30AM - 11:42AM |
NA.00005: Leadership Class Configuration Interaction Code - Status and Opportunities James Vary With support from SciDAC-UNEDF (www.unedf.org) nuclear theorists have developed and are continuously improving a Leadership Class Configuration Interaction Code (LCCI) for forefront nuclear structure calculations. The aim of this project is to make state-of-the-art nuclear structure tools available to the entire community of researchers including graduate students. The project includes codes such as NuShellX, MFDn and BIGSTICK that run a range of computers from laptops to leadership class supercomputers. Codes, scripts, test cases and documentation have been assembled, are under continuous development and are scheduled for release to the entire research community in November 2011. A covering script that accesses the appropriate code and supporting files is under development. In addition, a Data Base Management System (DBMS) that records key information from large production runs and archived results of those runs has been developed (http://nuclear.physics.iastate.edu/info/) and will be released. Following an outline of the project, the code structure, capabilities, the DBMS and current efforts, I will suggest a path forward that would benefit greatly from a significant partnership between researchers who use the codes, code developers and the National Nuclear Data efforts. [Preview Abstract] |
Saturday, October 29, 2011 11:42AM - 11:54AM |
NA.00006: New Directions for Nuclear Data Richard Firestone The evaluation of nuclear data has gone on for over 75 years. After WWII it was realized that the rate of accumulation of nuclear data had become too rapid for individual scientists and engineers to scan the literature so the modern nuclear data program was funded in the US by an act of Congress under the leadership of Katherine Way. In the 1970's at Oak Ridge National Laboratory the Nuclear Data Sheets ENSDF file format was designed and continues to be used, largely unchanged, today. Although originally envisioned to support nuclear applications, ENSDF today now largely supports basic nuclear structure research. As data evaluation became a specialization a gulf developed between the research, application, and data communities that has widened over time. At this juncture in history we are facing the joint dilemmas of disconnects between research and data activities, an aging nuclear data workforce, and pressures from funding agencies to work more efficiently. In this talk I will discuss recent developments and opportunities in nuclear data and the challenges ahead of us to modernize the nuclear data program and better integrate it into the nuclear physics research community. [Preview Abstract] |
Saturday, October 29, 2011 11:54AM - 12:06PM |
NA.00007: Comparison of Nuclear Mass Models with the Nuclear Mass Toolkit online at nuclearmasses.org Caroline D. Nesaraja, Michael S. Smith, Eric J. Lingerfelt, Hiroyuki Koura, Filip G. Kondev Nuclear masses are crucial in many areas of basic and applied nuclear science, ranging from r-process nucleosynthesis in supernovae to developing new models of superheavy nuclei. There is significant international effort in new mass measurements, new theoretical mass models, and new mass evaluations -- but the dissemination of mass information has not kept pace with these important developments. We have built an online, dedicated suite of codes to address this problem -- the {\bf Nuclear Mass Toolkit} at {\bf nuclearmasses.org}. This free, platform-independent system enables researchers to quickly and efficiently share, manage, visualize, access, manipulate, compare, and analyze nuclear mass datasets. With our system, researchers can upload their own mass datasets, store them, share them with colleagues, quickly and easily visualize them in customizable 1D and 2D plots, and calculate and plot RMS differences. We will demonstrate the utility of our site by comparing the RMS deviations of a variety of different theoretical mass models from the AME2003 evaluated masses, over a variety of mass ranges. [Preview Abstract] |
Saturday, October 29, 2011 12:06PM - 12:18PM |
NA.00008: Decay Heat Calculations for $^{235}$U T.D. Johnson, A. Sonzogni, E. McCutchan Following a nuclear reactor shutdown, a major issue is the decay heat due to radioactive decay of fission products and actinides. Contributing to this are light particles (\emph{e.g.}, \begin{math}\beta\end{math}- electrons), heavy particles (\emph{e.g.}, delayed neutrons), and electromagnetic radiation. Sources of uncertainty include probabilities for the formation of specific fission products, and incomplete knowledge of the levels of daughter nuclei. The latter is partially addressed by using Total Absorption Gamma Spectrocopy (TAGS). Earlier calculations are based on older decay schemes and sometimes less precise, mass measurements. In part to facilitate these calculations, the decay sub-library for the Evaluated Nuclear Data File was updated using the Evaluated Nuclear Structure Data Files with the latest mass measurements. The update includes electron conversion coefficients calculated using the Band-Raman Internal Conversion and ``Frozen Orbital'' approximation. The updated library was used in conjunction with available TAGS data to obtain preliminary updated decay heat calculations for $^{235}$U. [Preview Abstract] |
Saturday, October 29, 2011 12:18PM - 12:30PM |
NA.00009: Measurement of the Absolute Elastic and Inelastic Differential Neutron Cross Sections for $^{23}$Na between 2 and 4 MeV Ajay Kumar, M.T. McEllistrem, B.P. Crider, E.E. Peters, F.M. Prados-Estevez, A. Chakraborty, S.W. Yates, A. Sigillito, P.J. McDonough, L.J. Kersting, C.J. Luke, S.F. Hicks, J.R. Vanhoy Elastic and inelastic neutron scattering angular distributions for $^{23}$Na sample were measured at the University of Kentucky using the time-of-flight (ToF) technique, between 2 and 4 MeV incident neutron energies.Normalization of yields into scattering cross sections was accomplished by comparison of Na yields to the yields obtained from hydrogen in polyethylene samples via the well-known n-p scattering cross sections.The $^{3}$H(p,n) differential cross sections are used to determine the energy-dependent efficiency of the main detector. Because the efficiency of this detector appears as a ratio in the comparison of scattered yields from different samples, the absolute values of the $^{3}$H(p,n) cross sections are not critical, but their energy dependence is. [Preview Abstract] |
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