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At least 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Nuclear Data Sheets for A=158

The experimental results published before February 2017 from the various reaction and decay studies leading to nuclides {sup 158}Nd, {sup 158}Pm, {sup 158}Sm, {sup 158}Eu, {sup 158}Gd, {sup 158}Tb, {sup 158}Dy, {sup 158}Ho, {sup 158}Er, {sup 158}Tm, {sup 158}Yb, {sup 158}Lu, {sup 158}Hf, {sup 158}Ta, {sup 158}W in the A=158 mass chain have been reviewed. These data are summarized and presented, together with adopted level schemes and properties. Large sections of the mass chain are almost identical to the ones in the previous 2004He05 NDS publication by R.G. Helmer.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Recognizing Unrecognized Sources of Uncertainty (USU) in Nuclear Data

Historically, time-of-flight (TOF) nuclear cross section measurements on different nuclides are assumed to be uncorrelated if they were recorded in different facilities with identical methods, identical facilities with different methods, and even identical facilities with identical methods. Ideally, measurements of different nuclides would truly be uncorrelated thus providing independent assessments of some cross section. In reality, correlations exist between measurements but are simply assumed to be unimportant. To eliminate these qualitative assumptions, in this paper we make a counter-intuitive suggestion to perform an intentionally correlated measurement of energy-differential fission and capture reactions for nuclides in a single criticality safety benchmark during a single experimental campaign. While this would introduce undesirable correlations, it would fully quantify correlations between datasets, rather than assume that the correlations do not exist.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Users Guide to SAMINT: A Code for Nuclear Data Adjustment with SAMMY Based on Integral Experiments

The purpose of this project is to couple differential and integral data evaluation in a continuous-energy framework. More specifically, the goal is to use the Generalized Linear Least Squares methodology employed in TSURFER to update the parameters of a resolved resonance region evaluation directly. Recognizing that the GLLS methodology in TSURFER is identical to the mathematical description of the simple Bayesian updating carried out in SAMMY, the computer code SAMINT was created to help use the mathematical machinery of SAMMY to update resolved resonance parameters based on integral data. Minimal modifications of SAMMY are required when used with SAMINT to make resonance parameter updates based on integral experimental data.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Imperfect World of beta beta-decay Nuclear Data Sets

The precision of double-beta ββ-decay experimental half lives and their uncertainties is reanalyzed. The method of Benford's distributions has been applied to nuclear reaction, structure and decay data sets. First-digit distribution trend for ββ-decay T 2v 1/2 is consistent with large nuclear reaction and structure data sets and provides validation of experimental half-lives. A complementary analysis of the decay uncertainties indicates deficiencies due to small size of statistical samples, and incomplete collection of experimental information. Further experimental and theoretical efforts would lead toward more precise values of-decay half-lives and nuclear matrix elements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

Nuclear Data Sheets for A=246

For this work, available information pertaining to the nuclear structure of ground and excited states for all known nuclei with mass number A = 246 have been compiled and evaluated. The adopted level and decay schemes, as well as the detailed nuclear properties and configuration assignments based on experimental data, are presented for these nuclides. When there are insufficient data, expected values from systematics of nuclear properties and/or theoretical calculations are utilized. Unexpected or discrepant experimental results are also noted. In cases where weighted averaging procedures have been used, the assigned uncertainty in the result is generally not lower than the lowest uncertainty in the data points used in the procedure.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Developing a Continuous Nuclear Data Evaluation Method for the Resolved and Unresolved Resonance Regions With FITAPI and SAMMY [Poster]

SAMMY is an R-matrix Bayesian fitting program used in the analysis of nuclear cross section data. SAMMY produces separate cross section models in the resolved and unresolved resonance regions. This project develops a new method of continuous evaluation joining both energy regions with FITAPI. Full energy spectrum model introduces cross covariance between physics models allowing more accurate description of uncertainty. Consistency developed between physics models by the use of a unique set of prior parameters. An unresolved region cross section developed with sensitivity to resolved cross section. Incorporation into ORNL FITAPI provides access to greater number of parameter estimation algorithms.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2015

Designing a new structure for storing nuclear data: Progress of the Working Party for Evaluation Cooperation subgroup #38

An international effort is underway to design a new structure for storing and using nuclear reaction data, with the goal of eventually replacing the current standard, ENDF-6. This effort, organized by the Working Party for Evaluation Cooperation, was initiated in 2012 and has resulted in a list of requirements and specifications for how the proposed new structure shall perform. The new structure will take advantage of new developments in computational tools, using a nested hierarchy to store data. Here, the structure can be stored in text form (such as an XML file) for human readability and data sharing, or it can be stored in binary to optimize data access. In this paper, we present the progress towards completing the requirements, specifications and implementation of the new structure.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2011

Nuclear Data Verification and Standardization

The objective of this interagency program is to provide accurate neutron interaction verification and standardization data for the U.S. Department of Energy Division of Nuclear Physics programs which include astrophysics, radioactive beam studies, and heavy-ion reactions. The measurements made in this program are also useful to other programs that indirectly use the unique properties of the neutron for diagnostic and analytical purposes. These include homeland security, personnel health and safety, nuclear waste disposal, treaty verification, national defense, and nuclear based energy production. The work includes the verification of reference standard cross sections and related neutron data employing the unique facilities and capabilities at NIST and other laboratories as required; leadership and participation in international intercomparisons and collaborations; and the preservation of standard reference deposits. An essential element of the program is critical evaluation of neutron interaction data standards including international coordinations. Data testing of critical data for important applications is included. The program is jointly supported by the Department of Energy and the National Institute of Standards and Technology.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2015

Nuclear Data Sheets for A = 21

This evaluation of A = 21 has been updated from previous evaluations published in 2004Fi10, 1998En04, 1990En08, and 1978En02. Coverage includes properties of adopted levels and γ-rays, decay-scheme data (energies, intensities and placement of radiations), and cross reference entries. The following tables continue the tradition of showing the systematic relationships between levels in A = 21. Much of the new data in this evaluations were taken directly from the xundl database, compiled under the direction of Balraj Singh, McMaster University. The evaluator is particularly appreciative of the efforts of the xundl compilers.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2012

Nuclear Data Sheets for A=159

The experimental results from the various reaction and radioactive decay studies leading to nuclides in the A = 159 mass chain have been reviewed. Nuclides ranging from Pm (Z = 61) through Os (Z = 74) are included. These data are summarized and presented, together with adopted level schemes and properties. This work supersedes the previous evaluation of the data on these nuclides (2003He11).

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2019

Nuclear Data Sheets for A=105☆

This work presents new evaluation of A=105 nuclear structure and decay data. It covers a range of nuclei from the very neutron-rich {sup 105}{sub 38}Sr to the extremely neutron-deficient {sup 105}{sub 52}Te, known also to be the doughter of the lightest alpha decaying nucleus {sup 109}I. The work is based on experimental studies performed in the last 73 years, where A=105 nuclei were produced in particle transfer, fusion/evaporation reactions, sponataneus and induced fission, fusion and fragmentation of relativistic beams, radioactive decay etc.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2014

Neutron Cross Section Measurements at ORELA for Improved Nuclear Data and Their Application

Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved-resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high-power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to {approx}600 keV, which is important for many nuclear criticality safety applications.

43 PARTICLE ACCELERATORS↗