Multielemental analysis of soil samples by fast-neutron activation

Neutron activation analysis (NAA) have been used for the determination of major, minor, and trace elements in 20 soil samples from 5 crop fields of the Crop Research Centre, Pantnagar, India. Fast neutron activation analysis (FNAA) and cyclic neutron activation analysis (CNAA) have been used to determine the concentrations of various elements. The results for minor and trace elements are compared with the level of abundances of world soils. The present study provides the basic data of elemental concentrations in soil samples of 5 major crop fields located in one of the leading agricultural universities of India for future measurements with the objectives of efficient use of fertilizers and pesticides in accordance with the high yield.     

Methods for preparing comparative standards and field samples for neutron activation analysis of soil

One of the more difficult problems associated with comparative neutron activation analysis (CNAA) is the preparation of standards which are tailor-made to the desired irradiation and counting conditions. Frequently, there simply is not a suitable standard available commercially, or the resulting gamma spectrum is convoluted with interferences. In a recent soil analysis project, the need arose for standards which contained about 35 elements. In response, a computer spreadsheet was developed to calculate the appropriate amount of each element so that the resulting gamma spectrum is relatively free of interferences. Incorporated in the program are options for calculating all of the irradiation and counting parameters including activity produced, necessary flux/bombardment time, counting time, and appropriate source-to-detector distance. The result is multi-element standards for CNAA which have optimal concentrations. The program retains ease of use without sacrificing capability. In addition to optimized standard production, a novel soil homogenization technique was developed which is a low cost, highly efficient alternative to commercially available homogenization systems. Comparative neutron activation analysis for large scale projects has been made easier through these advancements. This paper contains details of the design and function of the NAA spreadsheet and innovative sample handling techniques.     

The upgrading of the cyclic neutron activation analysis facility at the Dalat research reactor

Journal of Radioanalytical and Nuclear Chemistry - The cyclic neutron activation analysis (CNAA) facility based on a pneumatic transfer system for short irradiation and rapid counting has recently...     

Applications of neutron activation to microelectronic materials research at the Cornell TRIGA reactor

We present results from our use of neutron activation analysis (NAA) for the measurement and interpretation of the elemental content of materials being researched for applications in microelectronics. Examples include characterization of silicon-germanium and nickel silicide alloys, magnesium silicate crystals and ceramics for packaging of integrated circuits. High resolution delayed X-ray spectroscopy has been successfully employed as a complement to conventional gamma-ray analysis for determination of relative impurity concentrations. Fast neutron induced interferences are removed from gamma-ray spectra via the internal standard correction technique, based on the measurement of fast reaction rates.     

The significance of hair mineral analysis as a means for assessing internal body burdens of environmental pollutants: Results from an IAEA Co-ordinated Research Programme

During a five-year period, the International Atomic Energy Agency supported a Coordinated Research Programme (CRP) to investigate the quantitative relationship between internal body burdens of a number of elements of environmental health significance and their respective concentrations in hair. The use of nuclear-related analytical techniques, such as neutron activation analysis, X-ray fluorescence, particle-induced X-ray emission and radiotracers, was emphasized. One aspect of the CRP focused on studies in man, using autopsy cases, of mineral distribution in five tissues, i.e. liver, kidney, lung, brain and bone in addition to hair, and the elements of primary importance were As, Cd, Cu, Hg, Pb, Se and Zn. Emphasis was placed on analytical quality assurance. Hair and internal tissue samples were obtained from subjects from Bulgaria, China, the former German Democratic Republic, Hungary, Japan, Norway and Sweden.     

Prompt Gamma Neutron Activation Analysis of 316-L Stainless Steel

Prompt gamma-rays from thermal neutron capture reaction have been used to measure the concentrations of the main constituents namely Fe, Ni and Cr in 316-L stainless steel using recently established prompt gamma neutron activation analysis (PGNAA) facility at Pakistan Institute of Nuclear Science and Technology (PINSTECH). High resolution, high purity germanium detector with 40% relative efficiency was employed for the gamma-ray spectroscopy of the samples. The interference-free full energy gamma-ray peaks of the elements of interests were selected in the high energy low background region (5.0–9.0 MeV). The efficiency calibration of the detector was performed using ultra pure standards of chromium and chlorine obtained respectively from Merck and Alpha Inorganics. This paper describes, in addition, the salient features as well as the background of establishing PGNAA facility at the Institute.     

Determination of rare earth elements in Taiwan monazite by chemical neutron activation analysis

Taiwan monazite is a unique mineral obtained from the heavy sand found in the river floor of Tzuo-suei river and En-suei river. Both rivers are flowing parallel with separated narrow area into the sea at southwestern coast of Taiwan. The characteristic of monazite is that it contains considerable rare earth elements (REEs). REEs are considered very useful elements in the local industries and scientific researches such as ceramic, semiconductors, and glass optics. In this study, chemical neutron activation analysis (CNAA) was used to determine the contents of REEs in Taiwan monazite. A few milligram of monazite was digested in the microwave oven for 25 minutes with mixed acid (conc. HNO₃ and HClO₄). REEs were preconcentrated by hydrated magnesium oxide and CNAA was performed.     

Usefulness of thermal and epithermal cyclic activation analysis with a reactor system

A new cyclic activation system (CAS) has recently been installed at the University of London Reactor and is briefly described. It has the unique feature that it allows choice as to whether irradiations are to be carried out under cadmium or in a bare tube and thus both epithermal and thermal cyclic activation analysis can be performed. Measurements in this work, have been carried out using a Ge(Li) detector but the facility allows other detectors to be used and an additional return line from the central distributive mechanism of the system (not yet installed) will allow samples to be cycled to and from a neutron detector thus providing the possibility of measuring radionuclides emitting delayed neutrons. By way of illustration of the theory of cyclic activation analysis, since the paper is to serve as an introduction to other papers in the conference using the technique, the results of a calculation for the detection of uranium under thermal and epithermal conditions are presented and compared to conventional activation. The usefulness of cyclic neutron activation analysis (CNAA) is also demonstrated in cases where identification of an isotope through its gamma-ray energy alone is not sufficient and conformation is achieved through determination of the half-life of the activity of interest, without resort to further experimental work or additional instrumentation. This leads on the thorny problem as to whether Poisson statistics should continue to be used in cases where the period of observation is of the same order as the decay constant of the activity of interest and it is pointed out how CNAA can be employed to extract the information required if a binomial-type statistical density function is used. Finally in order to prove the system and the cyclic method and as a preliminary to a larger project, prepared single element standards and standard reference materials [NBS Orchard Leaves, NBS Bovine Liver, IAEA Animal Blood, IAEA Hair standard and Bowen's Kale] are analysed under the two cyclic irradiation conditions. Sensitivities and cadmium ratios are obtained for the twelve elements from the elemental standards (Na, Al, Sc, Ge, Se, Rh, Pd, Ag, Ce, Er, Hf and Pb) and detection limits for a number of elements of interest presented for the standard reference materials.     

Application of INAA to ancient bricks for grouping study using trace elements

The paper presents the chemical composition analysis results of 57 ancient clay bricks obtained from Buddhist sites of two major locations of Andhra Pradesh, India. Samples were analyzed by instrumental neutron activation analysis (INAA) using high flux reactor neutrons and high resolution gamma ray spectrometry. Major, minor and trace concentrations of 23 elements were determined by relative method of NAA. For the grouping/provenance study, statistical cluster analysis was performed using concentrations of 14 selected elements namely Sc, Cr, Fe, Co, Zn, Cs, La, Ce, Eu, Tb, Yb, Lu, Ta and Th. The cluster analysis results indicated two major groups, which are in good agreement with the collection history of samples. Accuracy of the method was evaluated by analyzing two IAEA reference materials, RMs SL-1 and Soil-7.     

Application of NAA standardization methods using a low power research reactor

Two widely used neutron activation analysis (NAA) standardization methods (relative and k ₀) have been validated at the Ghana Research Reactor-1 (GHARR-1) Centre using environmental and biological standard reference materials (SRMs). The samples were IAEA Soil-7 as an environmental sample, and NIST Orchard Leaves 1571 as a biological sample. The qualitative and quantitative analyses were done using a high resolution Canberra N-type high purity germanium (HPGe) detector. The accuracy and precision were evaluated for the elements analysed. The concentrations of most of the elements were found to be within 10% of the certified values. Precision was calculated from six replicate measurements and was found to be within 15%.     

Determination of vanadium in high grade carbons by radioanalytical methods

The present work deals with the determination of vanadium in high grade carbons by three radioanalytical methods, viz. thermal neutron activation analysis with an accelerator, thermal neutron activation analysis with a reactor and proton induced X-ray emission analysis with an accelerator. It is cleared from this study that thermal neutron activation with an accelerator is more convenient for the rapid and non-destructive analysis of ppm-level vanadium in bulk carbons than thermal neutron activation analysis with a reactor. Proton induced X-ray emission is less useful for the analysis of bulk samples.     

Multi-element analysis of soil from the north-western region of India by neutron activation analysis using the single comparator method with special reference to selenium toxicity

The single comparator (k₀) instrumental neutron activation analysis (INAA) was employed to determine the elemental composition of soil from the north-western region of India. The radiometric assay was carried out using high resolution gamma-ray spectrometry. Seventeen elements were detected including selenium whose concentration was found to be in the range of 1.02 to 6.79 mg/g.     

Determinations of silicon and phosphorus in rice planted in a district of high incidence of amyotrophic lateral sclerosis by neutron activation and X-ray fluorescence analyses

Silicon and phosphorus contents in polished and unpolished rice planted in a district of high incidence of amyotrophic lateral sclerosis (ALS) have been determined by neutron activation and X-ray fluorescence methods, and compared with those from control areas. In the neutron activation analysis, beta-ray spectra of 32P produced by the 31P(n, gamma)32P reaction on polished and unpolished rice were measured with a low background beta-ray spectrometer. In the X-ray fluorescence analysis, characteristic X-rays were analyzed with a wavelength dispersive X-ray fluorescence spectrometer. Silicon contents in polished and unpolished rice from the ALS area are 42 micrograms.g-1 and 370 micrograms.g-1, respectively, and the corresponding phosphorus contents are 1,210 micrograms.g-1, and 3,370 micrograms.g-1, respectively. The data for ALS area are equal to those for the control area within standard deviation.     

Multielemental analysis of soils by instrumental neutron activation analysis

The results of an instrumental neutron activation analysis of some elemental concentrations in different soil samples near the industrial areas at Tirupati, India, are reported. Altogether 14 elements, Sm, La, Cr, Co, Zn, Cs, Ce, Th, Rb, Na, K, Sr, Fe and Eu were determined. The samples were irradiated with neutrons at the 100 kW Triga - Mainz research reactor and the induced activities were measured by gamma-ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector in connection with a multichannel analyzer. The results are discussed.     

Determination of aluminium contents in selected food samples by instrumental neutron activation analysis

Food and food products are the main sources of Aluminium entering the human body. In order to know aluminium contents in food and food products, selected 26 samples from local market were analyzed by instrumental neutron activation analysis (INAA) using reactor neutrons and high resolution gamma-ray spectrometry. INAA using 1,779 keV γ-ray of ²⁸Al (2.24 min) was used for aluminium concentrations in the range of 33–529 mg kg^?1. Two NIST standard reference materials (SRMs) and two IAEA reference materials (RMs) were analyzed by INAA for quantification of aluminium as a part of method validation.     

Analysis of SMELS by k 0-based IM-NAA method using PFTS position of KAMINI reactor for quality control exercise

As a part of QA/QC of k ₀-based internal monostandard neutron activation analysis (IM-NAA), three types of synthetic multielement standards (SMELS) were analyzed using pneumatic fast transfer system irradiation position of KAMINI reactor, IGCAR. Radioactive assay of activation products was carried out by high resolution gamma ray spectrometry. IM-NAA was used to determine relative concentration ratios of 22 elements with respect to gold internal monostandard. Absolute concentrations were calculated using assigned concentration of Au in all the types of SMELS. Z-score values within ±1 at 95.5 % confidence level and percentage deviations within ±5 % indicated good quality of the results by IM-NAA in most of the cases. Using this methodology, an ilmenite mineral sample was analyzed and concentrations of 14 elements were determined using Sc as monostandard.     

Studies of kidney stones using INAA,EDXRF and XRD techniques

Four kidney stones collected from patients being treated in the Advance Urology Centre of PGIMR, Chandigarh were characterized using instrumental neutron activation analysis (INAA), energy dispersive X-ray fluorescence (EDXRF) and X-ray diffraction (XRD) techniques. For INAA, samples were irradiated in tray rod facility of Dhruva reactor, Mumbai and pneumatic fast transfer system of KAMINI reactor, IGCAR, Kalpakkam. Radioactive assay was carried out using HPGe detector coupled to 8k channel analyzer. Elements determined in the samples by INAA are Zn, Sr, Co, Fe, Cr, Sc, Se, Na and Mn. EDXRF was used for the quantification of Ca. XRD patterns showed that three of the kidney stones are calcium oxalate stone and the other one is uric acid stone. The concentrations of trace elements in general were found to be higher in calcium oxalate stones and positive correlation was observed in the concentrations of Ca with Sr and Zn.     

An241Am−Be source based thermal neutron activation analysis facility at KFUPM

An instrumental thermal neutron activation analysis facility based, on a 16 Ci²⁴¹ Am–Be source, a high resolution -ray spectrometry setup and a PC-based data acquisition system at KFUPM is described. The thermal neutron flux distribution was determined from the induced activities of high purity indium foils. The absolute thermal neutron flux was calculated from the activities of bare and cadmium-covered gold foils at a position of 3 cm from the soource at which the flux reaches a maximum. The facility tests were carried out with the determination of manganese concentrations in six types of industrially important steel samples. The result of 1.33% manganese in SS-304 steel sample was in excellent agreement with the literature value. The method is nondestructive, economical and ideal for bulk analysis.     

Multielement NAA for the characterization of Saudi Arabian rocks

The instrumental neutron activation analysis technique (INAA) was used in the qualitative and quantitative analysis of 48 geological samples from the Umm Al-Birak area in the Kingdom of Saudi Arabia. The samples were properly prepared together with their standards and simultaneously irradiated in a neutron flux of 2.4 ·10¹² n·cm^–2 s^–1 in the reactor facilities of the National Tsing Hua University (THOR) in Taiwan. Gamma-spectra from the high resolution Ge(Li) detector were analyzed using the BRUTAl code. As a result of the analysis of the geological samples, 20 trace elements were identified qualitatively and quantitatively. These elements are: Co, Cr, Eu, Fe, Hf, K, La, Lu, Na, Rb, Sc, Sm, Ta, Tb, Th, U, Yb, Zn and Zr. The concentrations of these elements have been used in the investigations of the geochemistry of the Umm Al-Birak microgranite site using the BMDP computer code of the Ministry of Petroleum and Mineral Resources. This investigation showed that the high grade area is a differentiated rock that crystallized in a late stage of the Umm Al-Birak microgranite area.     

Activation analysis of alkaline rocks. A comparison between destructive and non-destructive methods

The United States Geological Survey reference sample AGV-1 andesite, and three alkaline rocks from the apatite mine of Jacupiranga, Brasil, were analyzed by thermal neutron activation analysis using destructive and non-destructive methods, and high resolution Ge(Li) gamma-ray detectors. One of the rocks, a carbonatite, was also analyzed by instrumental activation analysis with epithermal neutrons. A greater number of elements can be determined using the radiochemical separation, but the precision and accuracy attained by INAA and RNAA were of the same order for most of the elements analyzed. Epithermal activation was more advantageous for tantalum, terbium and holmium. Comparison of the analytical results for USGS reference sample (AGV-1) with the data published by others gave good agreement. Statistical tests used for comparison of the results of destructive and non-destructive methods, as well as other results are presented.