scholarly journals Information Files of 238U(n,f)/235U(n,f) NIFFTE fissionTPC Cross-sections for the Neutron Data Standards Project

2018 ◽  
Author(s):  
Denise Neudecker ◽  
Naohiko Otuka ◽  
Robert J. Casperson ◽  
Nathaniel S. Bowden ◽  
Luke Snyder ◽  
...  
Keyword(s):  
Cross Sections ◽  
Neutron Data ◽  
Data Standards

scholarly journals Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method

2020 ◽  
Vol 6 ◽  
pp. 19
Author(s):  
Denise Neudecker ◽  
Morgan Curtis White ◽  
Diane Elizabeth Vaughan ◽  
Gowri Srinivasan
Keyword(s):  
Experimental Data ◽  
Statistical Analysis ◽  
Information Content ◽  
Cross Section ◽  
Cross Sections ◽  
Nuclear Data ◽  
Current Version ◽  
Neutron Data ◽  
Data Standards ◽  
Actual Evaluation

Concerns within the nuclear data community led to substantial increases of Neutron Data Standards (NDS) uncertainties from its previous to the current version. For example, those associated with the NDS reference cross section 239Pu(n,f) increased from 0.6–1.6% to 1.3–1.7% from 0.1–20 MeV. These cross sections, among others, were adopted, e.g., by ENDF/B-VII.1 (previous NDS) and ENDF/B-VIII.0 (current NDS). There has been a strong desire to be able to validate these increases based on objective criteria given their impact on our understanding of various application uncertainties. Here, the “Physical Uncertainty Bounds” method (PUBs) by Vaughan et al. is applied to validate evaluated uncertainties obtained by a statistical analysis of experimental data. We investigate with PUBs whether ENDF/B-VII.1 or ENDF/B-VIII.0 239Pu(n,f) cross-section uncertainties are more realistic given the information content used for the actual evaluation. It is shown that the associated conservative (1.5–1.8%) and minimal realistic (1.1–1.3%) uncertainty bounds obtained by PUBs enclose ENDF/B-VIII.0 uncertainties and indicate that ENDF/B-VII.1 uncertainties are underestimated.

scholarly journals Including 238U(n,f)/235U(n,f) and 239Pu(n,f)/235U(n,f) NIFFTE fissionTPC Cross-sections into the Neutron Data Standards Database

2021 ◽  
Author(s):  
Denise Neudecker ◽  
Vladimir Pronyaev ◽  
Luke Snyder
Keyword(s):  
Cross Sections ◽  
Neutron Data ◽  
Data Standards

Relations Between Basic Nuclear Data and Single-Event Upsets Phenomena

MRS Bulletin ◽  
2003 ◽  
Vol 28 (2) ◽  
pp. 121-125 ◽  
Author(s):  
Jan Blomgren ◽  
Bo Granbom ◽  
Thomas Granlund ◽  
Nils Olsson
Keyword(s):  
Cross Sections ◽  
Nuclear Physics ◽  
Nuclear Data ◽  
Single Event Upset ◽  
Single Event ◽  
Neutron Data ◽  
Neutron Energy Range ◽  
Single Event Upsets ◽  
Technology Generation ◽  
Spallation Reactions

AbstractThis article approaches single-event upset (SEU) problems from the standpoint of experimental nuclear physics, with a focus on certain neutron experiments and neutron data essential for SEU studies. A review is given of some research programs, both basic and applied, that are strongly motivated by SEU applications. Some specific examples are presented from the The (short for Theodor) Svedberg Laboratory (TSL) in Uppsala, Sweden: First, using the quasi-monoenergetic neutron beam, SEU cross sections (of chips) are measured over the neutron energy range of 20–150 MeV. Data from the same technology generation, in general, can be fitted into a simple curve. Second, the particle origins of SEUs are discussed from the framework of neutron–nucleus spallation reactions.

scholarly journals Evaluation of the Neutron Data Standards

2018 ◽  
Vol 148 ◽  
pp. 143-188 ◽  
Author(s):  
A.D. Carlson ◽  
V.G. Pronyaev ◽  
R. Capote ◽  
G.M. Hale ◽  
Z.-P. Chen ◽  
...  
Keyword(s):  
Neutron Data ◽  
Data Standards

scholarly journals ROCOCO system of combined neutron constants – current status and results of testing using geometrical module of the MMK code

2018 ◽  
Vol 4 (3) ◽  
pp. 217-222 ◽  
Author(s):  
Gennady Zherdev ◽  
Tamara Kislitsyna ◽  
Mark Nikolayev
Keyword(s):  
Cross Sections ◽  
Monte Carlo Calculation ◽  
Current Status ◽  
Geometric Module ◽  
Neutron Data ◽  
Neutron Multiplication ◽  
Hexagonal Grids ◽  
Neutron Cross Sections ◽  
Further Development ◽  
Nuclide Composition

Results of studies aimed at the further refinement of the ROCOCO system (routine for calculation and organization of combined constants including cross-sections in group and subgroup representation with detailed description of energy dependence of neutron cross-sections) (Zherdev et al. 2018, Kislitsina et al. 2016) are presented in the paper. Inclusion of this system as a physical module into a set of Monte Carlo calculation codes with OOBG geometric module from the MMK code (Zherdev et al. 2003) is discussed. OOBG module is designed for calculation of neutron multiplication systems with heterogenous cores arranged as hexagonal grids with different degrees of complexity. The name ROCOCO-MMK was assigned to the complex. Results of testing the complex in the calculations of multi-zone neutron multiplication systems (including those with zones containing neutron moderator, zones with close composition but with different temperature, etc.) are described. Accounting for the dependence of constants for one and the same nuclide in the zones with different compositions and temperatures required substantial modernization of routines for preparation of constants for calculation described in (Zherdev et al. 2018). Algorithm for preparation of subgroup constants was modified, methodology for taking into account resonance self-screening of cross-sections within the range of unresolved resonances was improved, and other changes were introduced in the process of this modernization. Results of calculations are compared with data obtained using the MCNP-5 precision program (MCNP 1987), which is linked to the same library of evaluated neutron data ROSFOND as that used in ROCOCO. The ROCOCO-MMK includes procedures for registering different neutron flux functionals (also based on ROCOCO data), which allowed including it in the SCALA computation complex (Zherdev et al. 2003, Zherdev 2005), and performing step-by-step calculation of evolution of fuel nuclide composition during the fuel residence campaign. Directions for further development of the system are outlined in conclusion and, in particular, some possibilities of using the created software for further improvement of methods for preparation of few-group constants for calculations in diffusion approximation are examined.

scholarly journals A new evaluation of the neutron data standards

2017 ◽  
Vol 146 ◽  
pp. 02025 ◽  
Author(s):  
A.D. Carlson ◽  
V. Pronyaev ◽  
G.M. Hale ◽  
C. Zhenpeng ◽  
R. Capote ◽  
...  
Keyword(s):  
Neutron Data ◽  
Data Standards

Corrigendum to “Evaluation of the Neutron Data Standards” [Nucl. Data Sheets 148, p. 143 (2018)]

2020 ◽  
Vol 163 ◽  
pp. 280-281 ◽  
Author(s):  
A.D. Carlson ◽  
V.G. Pronyaev ◽  
R. Capote ◽  
G.M. Hale ◽  
Z.-P. Chen ◽  
...  
Keyword(s):  
Neutron Data ◽  
Data Standards

scholarly journals Applying a Template of Expected Uncertainties to Updating 239Pu(n,f) Cross-section Covariances in the Neutron Data Standards Database

2020 ◽  
Vol 163 ◽  
pp. 228-248 ◽  
Author(s):  
D. Neudecker ◽  
D.L. Smith ◽  
F. Tovesson ◽  
R. Capote ◽  
M.C. White ◽  
...  
Keyword(s):  
Cross Section ◽  
Neutron Data ◽  
Data Standards

Analysis of STEM micrographs of thick objects

1978 ◽  
Vol 36 (2) ◽  
pp. 106-107
Author(s):  
S. Golladay
Keyword(s):  
Inelastic Scattering ◽  
Multiple Scattering ◽  
Mass Distribution ◽  
Cross Sections ◽  
Phase Contrast ◽  
Image Point ◽  
Contrast Effects ◽  
Total Cross Sections ◽  
Elastic And Inelastic Scattering

The theory of multiple scattering has been worked out by Groves and comparisons have been made between predicted and observed signals for thick specimens observed in a STEM under conditions where phase contrast effects are unimportant. Independent measurements of the collection efficiencies of the two STEM detectors, calculations of the ratio σe/σi = R, where σe, σi are the total cross sections for elastic and inelastic scattering respectively, and a model of the unknown mass distribution are needed for these comparisons. In this paper an extension of this work will be described which allows the determination of the required efficiencies, R, and the unknown mass distribution from the data without additional measurements or models. Essential to the analysis is the fact that in a STEM two or more signal measurements can be made simultaneously at each image point.

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