[en] The Department of Energy (DOE) Order 5633.3A requires that the desired levels of precision and accuracy be established for accountability measurements, that the magnitude of these uncertainties be minimized for major contributors to the limit of error for inventory differences (LEID), and that methods be selected, validated, and qualified that are capable of providing the desired levels. In an effort to consistently determine the desired precision and accuracy levels for measurements within each of the nuclear material processing facilities at the Savannah River Site (SRS), a series of sensitivity studies were performed. To validate the current uncertainties as the goals, variance-propagated LEID models were used to determine the sensitivity of the LEID to each uncertainty value, using a nominal increase in the LEID as a figure-of-merit. These sensitivity studies provided the threshold values that each uncertainty needs to be held below. Engineering judgment and operational experiences were combined to qualitatively determine the need for improvement for each uncertainty. This paper describes the methodology of the sensitivity study, gives examples of the threshold values generated, and discusses the benefits of this approach in the approval process for proposed method changes

[en] The Environmental Restoration Department (ERD) assumed custody of the Old Solvent Tanks (Tanks S1-S22) in the Old Radioactive Waste Burial Ground (ORWBG, 643-E) from Waste Management in January 1991. The purpose of this Sampling and Analysis Plan (SAP) is to collect and analyze samples of the sludge solids, organic and aqueous phases to determine the level of radioactivity, the isotopic constituents, the specific gravity, and other physical parameters. These data must be obtained to evaluate the process safety of remediating the tanks, to determine the disposal path for the material in the tanks, and to determine the most viable closure technology for the tanks

[en] The objective of this project is to develop and evaluate ion induced desorption mass spectrometry for microscopic analysis. Briefly, the interaction of a microbeam (1-50μm diameter) of high energy heavy ions (84 MeV Kr⁺⁷) with the target surface desorbs and ionizes atoms and molecules. The desorbed ions are analyzed via time-of-flight mass spectrometry to determine the composition of the area addressed with the microbeam. An account of recent work is summarized

[en] This report describes a newly installed automated sample transfer and data acquisition and analysis system for oxygen determinations by neutron activation analysis. Oxygen is an important element for oil products research. The laboratory at the Westhollow Research Center of the Shell Development Company performs about 1600 oxygen determinations per year. (orig.)

[en] A multitude of ion-atom interactions are induced with projectiles of E>=0.1 MeV/nucleon. Analytical techniques derived from these include particle induced x-ray emission (PIXE), charged-particle activation analysis (CPAA), prompt nuclear reactions (PNR), and Rutherford backscattering spectrometry (RBS). Microscopic chemical analysis can be achieved with a small number of heavy fast projectiles and identification of the species desorbed from the sample surface via time-of-flight mass spectrometry. Experimental work with 84 MeV Kr ions indicates the following: high desorption yields can be obtained, mass spectrometry on microspots is feasible, and < 10⁶ atoms can be detected. (author) 7 refs.; 7 figs

[en] The desorption of atomic and molecular species from surfaces bombarded by fast heavy ions (Z ≥ 20; E ≥ 0.5 MeV/amu) is attractive for surface and microscopic characterization. Only a low-intensity probe beam is needed, the escape depth of desorbed species is shallow (ca. 10 A), and desorbed ions are efficiently detected with a time-of-flight mass spectrometer. Thus, particle-induced desorption mass spectrometry (PDMS) maintains sample integrity and charging effects are avoided. PDMS is useful for surface analysis of glasses and plastics by using californium-252 fission fragments for bombardment. Inorganic and organic surface constituents can be detected simultaneously; mass resolution is good. For lithium in glass, the detection limit is about 1 pg (ca. 100 μg g^-1). The PDMS technique can be combined with sequential ion etching for depth profiling. The feasibility of PDMS for microscopic analysis with a collimated 84-MeV Kr⁷⁺ beam (target diameter ca. 11 μm) is discussed. 11 refs.; 8 figs.; 1 table

[en] Time-of-flight spectrometry has been used for measurements of Cs⁺ ions emitted from cesium iodide targets by 600 keV hydrogen cluster ions Hn⁺, with n ranging from 5,7,9,... to 23. Evidence for an enhanced yield with respect to the sum of the individual atoms in a cluster is reported. The increase of the yield as a function of the projectile mass exhibits a fourth power dependence on the additive stopping power. Similar trends are found from preliminary results on the variation of the yield as a function of the cluster energy. Such non-linearity is discussed on the basis of existing models for monoatomic ions. (author)

[en] Yields for Cs⁺ ions emitted when cesium iodide targets are bombarded with clusters of formula Hsub(n)⁺ (with n ranging from 5 to 23) and of 600 keV energy have been measured. Results show that the yields vary as (dE/dx)⁴. Moreover there is evidence of an enhanced yield for a cluster ion over the sum of its individual atoms. (orig.)