[en] Within the past twenty years, new techniques and methods have emerged in response to new technologies that are based upon the performance of high-purity and well-characterized materials. The National Bureau of Standards, through its Standard Reference Materials (SRM's) Program, provides standards in the form of many of these materials to ensure accuracy and the compatibility of measurements throughout the US and the world. These standards, defined by the National Bureau of Standards as Standard Reference Materials (SRMs), are developed by using state-of-the-art methods and procedures for both preparation and analysis. Nuclear methods-activation analysis constitute an integral part of that analysis process

[en] A radiochemical method is described by which Np, Pu, Am and Cm in environmental samples can be determined. The transuranium elements are dissolved with acids out of the ashed material. Np/Pu is separated from Am/Cm by sequential extraction using TOPO/cyclohexane. The two fractions are radiochemically purified. Np-237, Pu-239+240, Pu-238 and Pu-236 as well as Am-243, Am-241, Cm-244 and Cm-242 are measured by alpha spectrometery. Pu-236, Am-243 and Np-239 are used to determine the respective yields. A fast method of Np-239 preparation is described. The chemical yields range from 60 to 90%. The detection limit attained per nuclide is 10 fCi/sample. 20 reference, 1 table

[en] Energy, and selected trace intakes of a sample of 90 noninstitutionalized Canadian women (mean age 66.2 +/- 6.2 years) living in a University community and consuming self-selected diets were assessed by chemical analysis of one-day duplicate diets and via 1-day dietary records collected by the subjects. Mean gross energy intake (determined via bomb calorimetry was 6.0 +/- 2.4 MJ (1435 +/- 580 kcal) and mean intakes of Cu and Mn (determined via atomic absorption spectrophotometry) were 1.2 +/- 0.6 mg and 3.8 +/- 2.1 mg/day, respectively. Instrumental neutron activation analysis was used for Cr - median = 77.4 μg/day; Se - median = 69.6 μg/day; Zn - mean + SD = 7.7 +/- 3.6 mg/day; Ag - median = 26.9 μg/day; Cs - median = 4.8 μg/day; Rb - median = 1.6 mg/day; Sb - median = 1.8 μg/day; Sc - median = 0.3 μg/day. Dietary intakes of Cr, Mn and Se for the majority of the subjects fell within the US safe and adequate range. In contrast, a high proportion of subjects had apparently low intakes of dietary Cu and Zn in relation to current US dietary recommendations

[en] In vivo analysis of body elements by neutron activation is an important tool in medical research. It has provided a direct quantitative measure of body composition of human beings in vivo. Basic physiological differences related to age, sex, race, and body size have been assessed by this noninvasive technique. The diagnosis and management of patients with various metabolic disorders and diseases has also been demonstrated. Two major facilities at Brookhaven are being utilized exclusively for in vivo neutron activation analysis (IVNAA) of calcium, phosphorus, sodium, chlorine, nitrogen, hydrogen, and potassium. These elements serve as the basis for a four compartment model of body composition: protein, water, mineral ash, and fat. Variations in these compartments are demonstrated in clinical research programs investigating obesity, anorexia, cancer, renal failure, osteoporosis, and normal aging. IVNAA continues to provide a unique approach to the evaluation of clinical diagnosis, efficacy of therapeutic regimens, and monitoring of the aging process. Classical balance studies usually require the patient to be admitted to a hospital for extended periods of confinement. IVNAA, however, allows for clinical management of the patient on an out-patient basis, an important aspect for treatment of chronic diseases. 25 references, 3 figures, 5 tables

[en] A new gamma ray analysis program based on SAMPO algorithms has been developed for use on PDP-11 and VAX computer systems. The program was designed to take maximum advantage of the matrix formulation method of nuclide identification. This allows the peak search algorithm to be optimized for sensitivity to small spectral peaks without significant reduction in the ability to identify components of unresolved multiplets

[en] A procedure was developed for measuring Pu-241 by liquid scintillation counting. Pu-241 was measured in the gaseous effluents of an incineration facility for radioactive burnable waste and of the Karlsruhe Nuclear Fuel Reprocessing Plant in West Germany. In addition, Pu-238, Pu-239 + 240, and Pu-241 were measured in the liquid effluents of the Karlsruhe Nuclear Research Center. Results of these investigations are presented. 3 references, 3 figures, 3 tables

[en] Time-of-event counting is a method for measuring very low levels of short-lived radionuclides. This method records the time at which each counting event of interest occurs. It was desired to compare this counting method with more conventional grouped-data counting methods in which a scaler or pulse-height analyzer is operated in recycle mode with printout of the counting data after each cycle. However, since this would be very difficult to do experimentally with sufficient statistical accuracy, a method for simulation of the required low-level counting data was developed. The simulation program and its use for evaluation of the time-of-event counting method is discussed

[en] The stable element composition of the American oyster Crassostrea virginica collected between June 1978 and August 1983 in the Chesapeake Bay in the vicinity of Calvert Cliffs Nuclear Power Plant was analyzed by neutron activation. The minimum, maximum and the mean values of the elemental concentrations are given. The seasonal effect and the linear correlation between elements entering the oyster composition are shown. 7 references, 1 figure, 4 tables

[en] Using the fast irradiation and measurement (FIM)-system with a neutron flux of 1.3 E+12n/cm²s, 12 elements Na, Cl, Pb, Li, In, Hf, Sc, Ag, Al, V, Ti, and Mn are determined in samples of 50 to 550 mg NBS-1648 urban particulate matter with single 2 s to 20 s irradiations, respectively. The method is capable of screening analyses the most time consuming step being sample preparation, i.e., weighing and welding the PE sample container. The experimental sensitivities for a 5 s or a 20 s irradiation are given. 6 references, 4 figures, 4 tables

[en] The technique of self-calibration, based on internal labelling of target samples with known amounts of a given element, is often used in conventional PIXE analysis of environmental and biological samples, usually when a large number of samples is to be analyzed. However, extreme care should be exercised when attempting to use self-calibration procedures for microPIXE analysis, because the microdistribution of the labelling element in a drop of solution, for example, is usually non-uniform, and particle microbeams with a homogeneous profile are difficult to obtain. The results of a series of scanning irradiations by a 20 μm proton beam across dried solution drops containing known initial concentrations of thorium which had been deposited onto two different backings are presented. Non-uniform distribution of thorium within the dried drops was observed