Toxicologically important trace elements in Iranian diets

The intake of aluminum, arsenic, cadmium, lead and mercury via the daily diet by Iranian population groups was determined. The relevant daily diets were prepared through dietary recording and duplicate portion, and the trace elements were measured using analytical methods based on NAA, ICP and AAS. The results for the Iranian diets are discussed and compared with corresponding ones from other countries. The project has been performed in the frame of a co-ordinated research project of the International Atomic Energy Agency with participants from various countries. This revised version was published online in July 2006 with corrections to the Cover Date.     

Determination of iodine in Asian diets by epithermal and radiochemical neutron activation analysis

Samples of diets from China, Japan, Korea, India, Pakistan and Philippines were analyzed using epithermal and radiochemical neutron activation analysis (ENAA and RNAA, respectively) within the framework of the IAEA project “Reference Asian Man”. The RNAA procedure was based on alkaline-oxidative fusion followed by extraction of elemental iodine in chloroform. The analytical methods employed are discussed in terms of detection limits and uncertainties of the results obtained. For quality control purposes a number of NIST biological reference materials, namely diets and foods were analyzed. Results for the diet samples indicate that achieving the WHO recommended daily allowance for iodine may be a problem in most of the above given countries. This revised version was published online in August 2006 with corrections to the Cover Date.     

Determination of trace elements in Iranian cigarette tobacco by neutron activation analysis

The concentration of 24 trace elements in the tobacco of two different brands of Iranian cigarettes, “Zarrin” and “Oshnoo”, has been measured by neutron activation analysis employing a high-resolution Ge(Li) detector. These elements are: Na, K, Sc, Cr, Mn, Fe, Co, Zn, Se, Br, Rb, Ag, Sb, Cs, Ba, La, Ce, Sm, Eu, Tb, Hf, Au, Hg and Th.     

Prompt gamma activation analysis and time of flight neutron diffraction on ‘black boxes’ in the ‘Ancient Charm’ project

The aim of the ‘Ancient Charm’ project is combining neutron tomography, prompt gamma activation analysis, time of flight neutron diffraction and neutron resonance transmission to generate elemental, and phase compositions of complex museum objects in 3D. To develop a protocol for such investigations, complex test samples were constructed and then analyzed by each method. The ‘black boxes’ are sealed iron and aluminum walled cubes, containing 2D or 3D arrangements of materials relevant for the compositions of archaeological samples. The experimental results obtained from bulk PGAA at BNC and TOF-ND at ISIS on two selected boxes are reported.     

Investigation,design and analysis of a fast neutron facility on beam port 4 at the University of Texas MARK II TRIGA Reactor

Graduate students in the Mechanical Engineering department at the University of Texas at Austin have designed and modeled a fast neutron prompt-gamma activation analysis facility as part of a new course introduced in the graduate program titled “The Design of Nuclear Systems.” The students were responsible for creating a design concept as well as implementing and modeling the concept to ensure its safety and functionality. The purpose of the class was to give graduate students the independence to create a project of their own vision, but to do so in a collaborative and formal manner as will be necessary in their future work. The fast neutron PGAA facility was successfully designed and computational models have been analyzed to display benefits of the fast neutron facility compared to the thermal neutron PGAA facility that also exists at The University of Texas at Austin.     

Characterization of a new external neutron beam facility at the Ohio State University

A thermal neutron beam facility has been designed and implemented at the Ohio State University Research Reactor. A project is underway to construct a large vacuum chamber such that the facility could have neutron depth profiling and neutron radiography capabilities as intended. The neutron beam is extracted from the reactor through a neutron collimator emplaced in Beam Port #2. The neutron spectrum entering the neutron collimator was unfolded from foil activation analysis results and also simulated with a full reactor core model in the MCNP Monte Carlo code. The neutron collimator uses polycrystalline bismuth as a gamma ray filter and single-crystal sapphire as a fast neutron filter. The beam is defined by multiple 3.0 cm diameter apertures made of borated aluminum. Characterization of the beam was performed using foil activation to find the flux and a low-budget neutron imaging apparatus to see the beam profile. The modulation transfer function was calculated to offer insight into the resolution of the imaging system and the collimation of the beam. The neutron collimator delivers the filtered thermal neutron beam with a ~4 cm diameter and a thermal equivalent flux of (1.27 ± 0.03) × 10⁷ n/(cm²s) at 450 kW power at the end of the collimator.     

The importance of nuclear analytical techniques in the determination of mineral micronutrients in Iranian daily diets

This article explains the application of a few nuclear and non nuclearanalytical techniques to determine a number of toxic and essential trace elementsin human daily intakes. The diets are the food patterns of different populationof Iranian provinces with different food habits.In this article a comparisonhas been made for mineral micronutrient intaken by the different populationvia the pattern of nutrients in their daily diets. In the meantime resultingoutcome from different analytical techniques including instrumental and radiochemicalneutron activation analysis have been compared and discussed.     

Design and construction of a facility for neutron activation analysis using the 14 MeV neutron generator at HMS Sultan

The potential for using a small, sealed tube, DT neutron generator for neutron activation analysis has been well documented but not well demonstrated, except for 14 MeV activation analysis. This paper describes the design, construction and characterization of a neutron irradiation facility incorporating a small sealed tube DT neutron generator producing 14 MeV neutrons with fluence rates of 2·10⁸ s⁻¹ in 4π (steady state) and 10¹¹ s⁻¹ in 4π (pulsed). Monte Carlo modeling using MCNP4c and McBend9 has been used to optimize the design of this facility, including the location of a thermal irradiation facility for conventional neutron activation analysis. A significant factor in designing the facility has been the requirement to conform with Ionising Radiation Regulations and the design has been optimized to keep potential radiation doses to less that 1 μSv/h at the external walls of the facility. Activation of gold foils has been used for flux characterization and the experimental results agree well with the modeling.     

Determination of boron, fluorine and some medium Z elements in diet samples

As part of the study on “Reference Asian Man” project, dried food from different Asian countries, in powdered form, was analyzed applying different techniques. Boron was determined by measuring prompt alphas in ¹¹B(p,α)⁸Be reaction with 800 keV protons. Coulomb excitation was used for F and Na determination based on ¹⁹F(p,p'γ)¹⁹F (γ -rays: 110 and 197 keV) and ²³Na(p,p'γ)²³Na (γ -ray: 440 keV) reactions with 2.3 MeV protons. The elements Sc, Co, Zn, Rb, Ag and Ce were determined by neutron activation analysis. The elements Ca, Mn, Fe, Ni, Cu, Zn, Sr and Mo were determined by X-ray fluorescence technique. This revised version was published online in August 2006 with corrections to the Cover Date.     

High-sensitive elemental analysis using multi-parameter coincidence spectrometer: GEMINI-II

In this study, using neutron activation analysis with multi-parameter coincidence method which was developed at Japan Atomic Energy Agency (JAEA), a non-destructive, ultra-high sensitive multi-elemental determination has been realized. The multi-parameter coincidence method is carried out with an array of 19 germanium detectors, GEMINI-II. Using this system, very weak γ-rays emitted from trace amounts of elements can be detected. The iridium concentration has been determined by means of neutron activation analysis with multi-parameter coincidence method for Cuban sediment samples across the K/T boundary strata.     

Investigations on the comparator technique used in epithermal neutron activation analysis

The possible extension of the comparator technique of reactor neutron activation analysis into the field of epithermal neutron activation has been investigated. Ruthenium was used for multi-isotopic comparator. Experiments show that conversion of the so-called reference k-factors—determined by irradiation with reactor neutrons—into k_epi-factors usable at activation under cadmium filter, can be evaluated with fair accuracy. Sources and extent of errors and their contribution to the final error of analysis are discussed. Based on the paper presented at the 2nd European Conference on Analytical Chemistry, 25–30 August, 1975, Budapest, Hungary.     

Sources of trace elements in total diet: A statistical approach

We have collected sixteen total diet samples from two socioeconomic groups in Turkey by duplicate portion techniques. Samples were homogenized with titanium-blade homogenizer, freeze dried and analyzed for their minor and trace elements mostly by neutron activation analysis. Bread and flour samples were also collected from the same regions and analyzed similarly by instrumental neutron activation analysis. We have determined concentrations of more than 25 elements in total diets, bread and flour, and fiber and phytate in total diets. We have determined daily dietary intakes of these population groups, probable source of elements through correlation coefficients, and enrichment factor calculations. This revised version was published online in July 2006 with corrections to the Cover Date.     

Neutron activation analysis by combined capture and decay gamma-spectrum method

The usual method of the neutron activation analysis is performed by the measurement of the characteristic nuclear radiations of the produced radioactive isotope by neutron irradiation. An advance in this field has recently been proposed in which the prompt capture γ-rays are observed in addition to the nuclear radiation of the produced nucleus. The characteristic energy spectra of these two kinds of γ-radiations are the main basis for the combined activation analysis method. The experimental setup consists of a γ-radiation pulse height energy spectrum system which is synchronized with a pulsing neutron generator of ‘D—T’ or ‘D—D’ reaction. The present results indicate that a qualitative and semi-quantitative determination of a number of elements is feasible, with an overall error of 10–15%.     

Instrumental neutron activation analysis of geological and pedological samples. Further investigation of epithermal neutron activation analysis using monostandard method

A comparative study is presented on neutron activation analysis of rock and soil samples using whole reactor neutron spectrum and epithermal neutrons with both relative and monostandard procedures. The latter procedure used with epithermal neutron activation analysis of soil samples necessitated the use of the “effective resonance integrals” which were determined experimentally. The incorporation of the β factor, representing deviation of reactor epithermal neutron flux from 1/E law, is developed in the present work. The main criteria for the choice of one or more of the procedures studied for a given purpose are also indicated. Analysis of 15 trace elements, Ca and Fe in the standard Japanese granite JC-1 using monostandard epithermal neutron activation gave results in good agreement with the average literature values. This paper is dedicated to the 80th birthday of Professor Dr. Robert Klement, University of Munich.     

Experimental sensitivities for 3 MeV neutron activation analysis

The experimental sensitivity for 72 different elements using 3 MeV neutron activation has been investigated. Using a 200 kV Cockcroft-Walton neutron generator with a 3 MeV neutron flux of about 1.5·10⁶n·cm⁻²·sec⁻¹, γ-ray spectra of 51 elements were obtained with a sufficient number of photopeak counts for sensitivity calculations using a photopeak integration method. A useful table summarizing the sensitivity results is given. That 3 MeV neutron activation analysis is practical, is demonstrated by the experimental sensitivities obtained. Guest worker from the Institute of Nuclear Techniques, Academy of Mining and Metallurgy, Krakow, Poland, at the National Bureau of Standards, 1968–1969.     

Application of neutron activation analysis to determine the contents and isotopic ratios of elements in rocks and minerals

Data on the applicability of neutron activation analysis to determine various rare and trace elements and the isotopic abundance of some of them in natural samples are discussed as relevant to the solution of various geological and geochemical problems. For the determination of minute amounts of elements from small weighed quantities of rocks and minerals a number of modifications of neutron activation analysis are used: analysis with the radiochemical separation of individual elements—RNAA (tantalum, tungsten, antimony, arsenic, molybdenum, rhenium, osmium, etc.) and analysis with semiconductor—Ge (Li)—gamma-spectrometry, which is multi-element and non-destructuve—INAA (scandium, europium, tantalum, iron caesium, rubidium, cobalt, antimony, etc.) or the combination of the latter with group radiochemical separation—IRNAA (alkaline, alkaline-earth, rare-earth elements, etc.). First steps have been made towards developing techniques for the determination of the isotopic rations of some elements by means of neutron activation method, e.g., the isotopic ratio of⁵⁸Fe/⁵⁴Fe. The accuracy of isotopic ratio determination is 1 to 3 relative per cent.     

Multielement analysis by neutron activation of tissues from swine administered copper supplemented diets

Instrumental neutron activation analysis was used to determine Co, Cu, Fe, Mg, Mn, Se and Zn in tissues from swine fed copper supplemented diets.     

Determination of aluminium in lutetium by instrumental neutron activation analysis

In lutetium metal 45 ppm aluminium have been determined by instrumental neutron activation analysis. Interference from the very intensive γ-radiation of^176mLu was eliminated by application of lead filters. The determination limit of the method was estimated to be 0.7 μg or 3 ppm Al.     

Estimation of the possibilities of a neutron generator-based source of thermalized neutrons for activation analysis

Characteristics of a source of thermal neutrons based on an evacuated NG-400 neutron generator with the maximum flux (Φ_f) 2 × 10¹¹ neutron/s for 14 MeV neutrons and 2 × 10⁹ neutrons/s for 3 meV neutrons have been investigated. The possibilities of its application for neutron activation analysis have been estimated. The distribution, composition, and density (φ_T) values of the thermal neutron flux have been measured in the inner cavity of the moderator using activation detectors. φ_T was 2 × 10⁸ and 2 × 10⁶ neutrons/cm² s for thermalized neutrons with energies of 14 and 3 MeV, respectively. The possibilities of the apparatus have been estimated theoretically and experimentally for the cases of thermalized neutrons of 14 MeV and 3 MeV.     

A cyclic neutron activation system using an isotopic neutron source for the measurement of short-lived isotopes

The design and construction of an activation analysis system using an isotopic neutron source which allows the measurement of prompt and delay gamma-rays, in conventional activation and cyclic activation modes, is briefly described with emphasis laid on its flexibility, transportability and low cost. Photon spectra obtained from the irrdiation of large samples under prompt, delay and cyclic conditions using both NaI(Tl) and Ge(Li) detectors are presented and described with respect to ‘in-vivo’ neutron activation analysis and the measurement of N, O, Na, P, Cl and Cd. It is pointed out that, despite the attractive possiblity of measuring Se in liver, ‘in-vivo’, by cyclic activation analysis, the system may potentially prove a very useful tool for industrial and other non-medical applications.