David B. Curtis

Bio: David B. Curtis is an academic researcher from Los Alamos National Laboratory. The author has contributed to research in topics: Uranium & Neutron temperature. The author has an hindex of 13, co-authored 29 publications receiving 530 citations.

Nondestructive determination of boron and cadmium in environmental materials by thermal neutron-prompt .gamma.-ray spectrometry

Abstract: Prompt ..gamma.. rays from thermal neutron induced nuclear reactions have been used to measure trace quantities of B and Cd in industrial and standard materials. The technique provides a rapid nondestructive analysis for > 0.05 ..mu..g of B. Repetitive analyses show the method to have a precision of 5%. The presence of large quantities of Na degrades the accuracy and precision of the B analysis. The technique also provides a method for the determination of Cd although it is not sufficiently sensitive to provide a practical alternative to more conventional methods.

Analysis of naturally produced technetium and plutonium in geologic materials.

Abstract: In uncontaminated natural materials, plutonium and technetium exist exclusively as products (daughters) of nuclear reactions in which uranium is the principal reactant (parent). Under conditions of chemical stability over geologic periods of time, the relative abundances of daughter and parent elements are fixed by the rates of nuclear reactions and the decay of the daughter radionuclide. The state of this nuclear secular equilibrium condition is the primary basis of the geochemical study of these elements in nature. Thus, it is critical that nuclear parent and daughter abundances are measured in the same sample. We have developed a quantitative procedure for measuring subpicogram quantities of plutonium and technetium in gram quantities of geologic matrices such as uranium ores. The procedure takes advantage of the aggressive properties of sodium peroxide/hydroxide fusion to ensure complete dissolution and homogenization of complex materials, the precision provided by isotope dilution techniques, and the...

A Compilation of New and Published Major and Trace Element Data for NIST SRM 610 and NIST SRM 612 Glass Reference Materials

Abstract: Microanalytical trace element techniques (such as ion probe or laser ablation ICP-MS) are hampered by a lack of well characterized, homogeneous standards. Two silicate glass reference materials produced by National Institute of Standards and Technology (NIST), NIST SRM 610 and NIST SRM 612, have been shown to be homogeneous and are spiked with up to sixty one trace elements at nominal concentrations of 500 μg g-1 and 50 μg g-1 respectively. These samples (supplied as 3 mm wafers) are equivalent to NIST SRM 611 and NIST SRM 613 respectively (which are supplied as 1 mm wafers) and are becoming more widely used as potential microanalytical reference materials. NIST however, only certifies up to eight elements in these glasses. Here we have compiled concentration data from approximately sixty published works for both glasses, and have produced new analyses from our laboratories. Compilations are presented for the matrix composition of these glasses and for fifty eight trace elements. The trace element data includes all available new and published data, and summaries present the overall average and standard deviation, the range, median, geometric mean and a preferred average (which excludes all data outside ± one standard deviation of the overall average). For the elements which have been certified, there is a good agreement between the compiled averages and the NIST data. This compilation is designed to provide useful new working values for these reference materials.

Measurement Methods to Determine Compliance with Ambient Air Quality Standards for Suspended Particles

Abstract: One of the most important parts of formulating a National Ambient Air Quality Standard is specifying the measurement methods for determining and attaining compliance. The samples taken for compliance are often pushed beyond their original purpose to identify sources, to evaluate the effectiveness of controls, and to determine relationships between pollution levels and public health. A full understanding of available sampling and analysis methods is needed, as well as an analysis of their costs, before acceptable monitoring approached can be specified. This review identifies issues related to measurement methods used to determine compliance with standards, describes current and future measurement methods and their limitations, and determines the extent to which existing technology can meet short-term and long-term needs for measuring compliance.