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Sections of this appendix are: Neutron Cross Section Library, Photonuclear Library, Probability Table Library, Thermal Library, Dosimetry Library, Neutron Activation Library, Photon Library, Delayed Fission Gamma Library, and Compendium examples.
The transfer of the Godiva IV experiment from the Los Alamos Critical Experiments Facility (LACEF) to the National Critical Experiments Research Center (NCERC) introduced a vastly different experiment room return to the neutron flux. The contribution of the background to the burst neutron energy spectrum is significant in the thermal and epithermal neutron energies. Target materials may be placed in various locations in the Godiva room, or outside of the room, for thermal neutron activation. Modeling of this dosimetry problem in Monte Carlo N-Particle (MCNP) presented a novel challenge compared to previous Godiva IV glory hole irradiation simulations. An advanced dosimetry modeling framework for high efficiency calculations in locations far from the Godiva IV fission source was desired. The mesh-based weight windows and point detector advanced variance reduction techniques in MCNP were implemented and tested using adaptations of the critical experiment benchmark model of the Godiva IV problem. The models were validated against measured activations of Nickel, Indium, Scandium, and Cobalt foils at locations 2 meters from the Godiva IV core. Dosimetry measurements were performed in collaboration with Sandia National Laboratory. The weight windows and point detector variance reduction coupled method resulted in the highest problem efficiency.
Abstract, introduction, and summary of work completed and products produced by DOE award SC002466. Primary products were six peer-reviewed publications and two PhD theses. This award also supported the operation of an underground HPGe detector and several radioassay measurements: one in a stand alone publication in Phys. Rev. C and the others in an upcoming nEXO radioassay summary paper. The nEXO collaboration aims to demonstrate the Majorana nature of the neutrino by observing the neutrinoless double-beta decay of 136 Xe with a next-generation experiment. The University of Kentucky nEXO group (UKY) operates a world-leading ultra-low-background γ-ray spectrometer as part of the nEXO radioactive background control R&D effort. The nEXO project is a proposed ton-scale neutrinoless double-beta decay experiment. The UKY PI is leading the radioactivity content assessment for all materials required by the nEXO project. As a subset of this task, UKY is also responsible for project-wide management of all low-background γ-ray spectrometry measurements; material assays with these types of instruments, together with ICP-MS, neutron-activation-analysis, and α-spectrometry, are critical to ensuring that the nEXO project can achieve its design sensitivity
Determination of the absolute and normalized abundances of scandium and yttrium in nakhlitic meteorites by neutron activation techniques
Accuracy of vacuum distillation, vacuum amalgamation, and neutron activation analyses of oxygen traces in potassium
Copper and zinc abundances in carbonaceous, enstatite and ordinary chondrite determined by neutron activation techniques
Neutron activation analysis techniques were employed for the study of the wear and performance characteristics of slip ring and rotor assemblies and of the problems arising from environmental conditions with special reference to surface contamination. Results showed that the techniques could be successfully applied to measurement of wear parameters.
Ultramafic rock content of Na, Mn, Cr, Sc and Co determined by neutron activation technique
Cl, Br and I abundances in carbonaceous chondrites analyzed by neutron activation in estimating primordial halogen abundance ratios
Rare earth elements abundance in meteoritic chondrites determined by radiochemical neutron activation analysis
Lunar composition spectroscopic analysis using neutron activated gamma ray emission from basalt and granite
Adsorption integral cesium reservoir containing porous refractory metal substrates, determining cesium contents in life test converter components by neutron activation analysis
Procedure for removal of sodium and bromine from KCl involves zone refining in dilute halogen atmosphere. Distribution of Na and Br at concentrations of parts per million is followed by neutron-activation analyses.
Rare earth elements and yttrium in meteoritic chondrules determined by radiochemical neutron activation analysis
Indium abundances in chondritic and achondritic meteorites and terrestrial rocks determined by radiochemical neutron activation analysis
Aluminum abundances in stony meteorites measured using nondestructive instrumental neutron activation analysis
Trace element abundances in L-chondrites determined by neutron activation analysis, and implications cosmothermometry
Bismuth concentrations in various carbonaceous and equilibrated chondrites determination by neutron activation technique