SCALE/DB-Public
This is a collection of public data produced by AMPX or curated from quality sources that the SCALE code system relies on for user problem input.
Brown, Jesse [Oak Ridge National Laboratory (ORNL)↗
Engineering topics
Johnson, Seth
Publications and source records attributed to Johnson, Seth.
Improvements of SCALE Infrastructure on Microsoft Windows [Slides]
This presentation is on improvements of SCALE infrastructure on Microsoft Windows. This presentation begins with an overview and history of the group and history of SCALE infrastructure and testing as well. Improvements made to testing and the introduction of the cloud is brought up. Other topics include: GitLab Testing Suite and Windows Toolchain. Benefits to testing, to developers, and to users are discussed.
96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
Secondary-Source Core Reload Modeling with VERA
The CASL reactor simulation package VERA has been adapted to provide high-fidelity simulation capabilities for modeling source range detector response during subcritical reactor configurations. New features include the activation and shuffling of secondary-source assemblies, use of burned fuel neutron emission data from the ORIGEN depletion solver to the MPACT deterministic neutron transport solver, allowance of user-defined sources in MPACT based on material composition, ability to solve the subcritical source-driven system with neutron multiplication using the MPACT diffusion solver, and transfer of the calculated fission source from MPACT to the continuous-energy Monte Carlo solver Shift for final detector response evaluation using the CADIS methodology for variance reduction. These new capabilities were benchmarked against Watts Bar Unit 1 plant operating data for the first few fuel loading steps and were found to demonstrate excellent agreement with the measured data.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Shift Validation Plan for CASL
This document outlines the benchmarks that will be used for Shift validation for CASL. This plan is divided into five main types of problems, with each building upon the previous: small criticality benchmark problems, including small reactor configurations and critical assemblies; full-core reactor benchmarks for light water reactors; fixed source coupled neutron-photon dosimetry benchmarks; depletion/burnup benchmarks ranging from small pincell problems to full-core reactor depletion; and full-core reactor performance benchmarks. Some of these benchmarks have measured data for comparison and some only have simulated Monte Carlo radiation transport code results for comparison. Upon completion of this validation plan, we will have confidence in Shift to provide reference results for CASL benchmarking.
22 GENERAL STUDIES OF NUCLEAR REACTORS↗
A critical assessment of stellar mass measurement methods
This is the second paper in a series aimed at investigating the main sources of uncertainty in measuring the observable parameters in galaxies from their spectral energy distributions (SEDs). In the first paper we presented a detailed account of the photometric redshift measurements and an error analysis of this process. In this paper we perform a comprehensive study of the main sources of random and systematic error in stellar mass estimates for galaxies, and their relative contributions to the associated error budget. Since there is no prior knowledge of the stellar mass of galaxies (unlike their photometric redshifts), we use mock galaxy catalogs with simulated multi-waveband photometry and known redshift, stellar mass, age and extinction for individual galaxies. The multi-waveband photometry for the simulated galaxies were generated in 13 filters spanning from U-band to mid-infrared wavelengths. Given different parameters affecting stellar mass measurement (photometric signal-to-noise ratios (S/N), SED fitting errors and systematic effects), the inherent degeneracies and correlated errors, we formulated different simulated galaxy catalogs to quantify these effects individually. For comparison, we also generated catalogs based on observed photometric data of real galaxies in the Great Observatories Origins Deep Survey-South field, spanning the same passbands. The simulated and observed catalogs were provided to a number of teams within the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey collaboration to estimate the stellar masses for individual galaxies. A total of 11 teams participated, with different combinations of stellar mass measurement codes/methods, population synthesis models, star formation histories, extinction and age. For each simulated galaxy, the differences between the input stellar masses, M{sub input}, and those estimated by each team, M{sub est}, is defined as Δlog(M)≡log(M{sub estimated})−log(M{sub input}), and used to identify the most fundamental parameters affecting stellar mass estimate in galaxies, with the following results. (1) No significant bias in Δ log(M) was found among different codes, with all having comparable scatter (σ(Δlog(M))=0.136 dex). The estimated stellar mass values are seriously affected by low photometric S/N, with the rms scatter increasing for galaxies with H{sub AB}>26 mag; (2) A source of error contributing to the scatter in Δ log(M) is found to be due to photometric uncertainties (0.136 dex) and low resolution in age and extinction grids when generating the SED templates; (3) The median of stellar masses among different methods provides a stable measure of the mass associated with any given galaxy (σ(Δlog(M))=0.142 dex); (4) The Δ log(M) values are strongly correlated with deviations in age (defined as the difference between the estimated and expected values), with a weaker correlation with extinction; (5) The rms scatter in the estimated stellar masses due to free parameters (after fixing redshifts and initial mass function) are quantified and found to be σ(Δlog(M))=0.110 dex; (6) Using the observed data, we studied the sensitivity of stellar masses to both the population synthesis codes and inclusion of nebular emission lines and found them to affect the stellar mass by 0.2 and 0.3 dex respectively.
79 ASTRONOMY AND ASTROPHYSICS↗
Exnihilo Transport Methods Manuals Revision 0
Exnihilo is a transport code system that contains both deterministic and stochastic (Monte Carlo) solvers. The deterministic solvers are contained in the Denovo package while the Monte Carlo solvers are implemented in the Shift package. This document explains the mathematical and numerical methods employed within Exnihilo. It is not a users guide, nor is it a code developer's manual. Naturally, there is cross-over between the code implementation and mathematical description of any given method, and these are included for the purpose of greater understanding where appropriate. The purpose of this document is to formally describe the equations that are solved by the various packages inside of Exnihilo. In general, linkages are not made between a given numerical method and the Exnihilo code base. This is largely due to the fact that the Exnihilo code base changes far more rapidly than the actual methods that it is solving. Thus, this documentation would go rapidly out of date if cross-references were made between the methods and the code that implements them. Instead, developers are encouraged to look at the Doxygen-produced code documentation that explains what each translation unit in the code is doing. Where necessary we will make distinctions between methods that are implemented in Exnihilo and methods that are documented to provide better understanding of the broader field and provide context for the chosen methods in Exnihilo.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Exnihilo User's Manuals Release 5.3 (Dev)
Exnihilo is a modern radiation transport framework that implements a variety of advanced solvers and solution method- ologies, enabling it to solve a wide variety of nuclear engineering and applications problems with the scalability to run on both desktop machines and leadership-class supercomputers. It supports "stand-alone" execution using its internal front ends, but its components (such as the the Denovo S N solver) are also integrated into other radiation transport codes.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Exnihilo Transport Methods Manual
Exnihilo is a transport code system that contains both deterministic and stochastic (Monte Carlo) solvers. The deterministic solvers are contained in the Denovo package while the Monte Carlo solvers are implmented in the Shift package. This document explains the mathematical and numerical methods employed within Exnihilo.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
A CRITICAL ASSESSMENT OF PHOTOMETRIC REDSHIFT METHODS: A CANDELS INVESTIGATION
We present results from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) photometric redshift methods investigation. In this investigation, the results from 11 participants, each using a different combination of photometric redshift code, template spectral energy distributions (SEDs), and priors, are used to examine the properties of photometric redshifts applied to deep fields with broadband multi-wavelength coverage. The photometry used includes U-band through mid-infrared filters and was derived using the TFIT method. Comparing the results, we find that there is no particular code or set of template SEDs that results in significantly better photometric redshifts compared to others. However, we find that codes producing the lowest scatter and outlier fraction utilize a training sample to optimize photometric redshifts by adding zero-point offsets, template adjusting, or adding extra smoothing errors. These results therefore stress the importance of the training procedure. We find a strong dependence of the photometric redshift accuracy on the signal-to-noise ratio of the photometry. On the other hand, we find a weak dependence of the photometric redshift scatter with redshift and galaxy color. We find that most photometric redshift codes quote redshift errors (e.g., 68% confidence intervals) that are too small compared to that expected from the spectroscopic control sample. We find that all codes show a statistically significant bias in the photometric redshifts. However, the bias is in all cases smaller than the scatter; the latter therefore dominates the errors. Finally, we find that combining results from multiple codes significantly decreases the photometric redshift scatter and outlier fraction. We discuss different ways of combining data to produce accurate photometric redshifts and error estimates.
79 ASTRONOMY AND ASTROPHYSICS↗