Neutron Activation Analysis Method Research Articles

Estimation of total as well as bioaccessible levels and average daily dietary intake of iodine from Japanese edible seaweeds by epithermal neutron activation analysis

An epi-thermal instrumental neutron activation analysis (EINAA) method in conjunction with Compton suppression spectrometry (EINAA-CSS) was used for the determination of total iodine in eight different species of edible seaweeds from Japan. This method gave an absolute detection limit of about 2 μg. The accuracy of the method was evaluated using various reference materials and found to be generally in agreement within ±6% of the certified values. The longitudinal distributions of iodine at different growing stages in Japanese sea mustard and tangle seaweeds were investigated. For a 150-cm-high tangle, the highest concentration (5,360 mg/kg) of iodine was found at the root, then decreased slowly to 780 mg/kg in the middle portion (60–75 cm), and increased to 2,300 mg/kg at the apex. On the other hand, for a 190-cm-high sea mustard the highest levels of iodine were found both at the roots (164 mg/kg) and apex (152 mg/kg) with lower values (98 mg/kg) in the middle section. In order to estimate the bioaccessible fraction of iodine, seaweeds were digested by an in vitro enzymolysis method, dietary fibre separated from residue, and both fractions analyzed by EINAA-CSS. The average daily dietary intakes of total (0.14 mg) as well as bioaccessible fraction (0.12 mg) of iodine from the consumption of sea mustards were estimated.

Characterization of geomaterials from NE Portugal using k 0-based instrumental neutron activation analysis (k 0-INAA) and gamma spectrometry methods

The main objective of this study is the elemental characterization of geomaterial samples (“soils” and Ranas), collected between 2007 and 2008, in the Morais Massif, (NE Mainland of Portugal) by using two complementary techniques: instrumental neutron activation analysis (INAA) and high resolution gamma spectrometry. Samples granulometric fractions lower than 63 μm were analyzed by gamma spectrometry, for artificial and natural radionuclides using HPGe detectors and by INAA, for chemical elements at the Portuguese research reactor, RPI. Statistical analysis, such as clusters analysis and Pearson correlations were applied to the obtained results. The enrichment factors were also calculated as an estimator of anthropogenic inputs in relation to the average crustal abundance. Group differentiation of Ranas and “soils” is clearly shown from cluster analysis. The strong correlation factors obtained between some chemical elements corroborates the origins and the geology/mineralogy of the area studied. The combined application of both nuclear analytical techniques has shown their importance in providing useful information for the future site and repository performance and safety assessment studies.

Determination of nickel in finished product alloys by instrumental neutron activation analysis and spectrophotometry

Nickel contents in different finished product alloys were determined using a k0-based internal monostandard instrumental neutron activation analysis (IM-INAA) method. Five stainless steels (SS) and three high nickel alloys were analyzed by IM-INAA. BCS CRMs 225/1 (low alloy steel) and 466 (austenitic SS) and NIST SRM 247 (high Ni alloy) were analyzed to evaluate the accuracy of the method. The results of CRMs and SS were found to be in good agreement with certified or specified values. The Ni contents in the high nickel alloys were also determined by relative method of NAA for verification. Nickel contents in BCS CRM 466 and SS 316M were determined by UV–Visible spectrophotometry and the values were found to be in good agreement with IM-INAA results.

Study of arsenic (As) mobilization in the Ganga Alluvial Plain using neutron activation analysis

In northern part of Indian sub-continent, As related environmental and health issues receive attention from all over the world. Forty-eight sediment samples were collected from the Ganga Alluvial Plain (GAP) and its weathering products (from the Gomati River) for the study of As distribution and mobilization. These sediment samples were analyzed by Instrumental Neutron Activation Analysis (INAA) method using Cirus Research Reacter of Bhabha Atomic Research Centre, Mumbai. Average As concentrations in the GAP sediments (10.44 mg kg−1), the Gomati River bed sediments (1.36 mg kg−1) and the Gomati River suspended sediments (5.30 mg kg−1) were reported. Significant decrease of As content from the alluvial sediments to the river sediments is a clear indication of its mobilization by chemical weathering processes of mineral biotite. Present study demonstrates the importance of INAA for quantification and mobilization of As and improves our understanding related to As related environmental issues in northern India and elsewhere.

Development and implementation of Høgdahl convention and Westcott formalism for k0-INAA application at Malaysian Nuclear Agency reactor

The present work shows the development of k0-instrumental neutron activation analysis (k0-INAA) method at the Malaysian Nuclear Agency research reactor. To use the k0-INAA method, two formalisms were regulated according to 1/ν and non-1/ν (n, γ) reaction nuclides. The reactor neutron spectrum parameters, the thermal to epithermal neutron flux ratio (f), the epithermal neutron flux shape factor (α) were measured using the bare bi-isotopic monitor and bare triple monitor methods, respectively, based on the Hogdahl convention. In addition, the modified spectral index $$ r(\alpha )\sqrt {T_{n} /T_{0} } $$ , the Westcott $$ g_{Lu} (T_{n} ) $$ factor and the absolute neutron temperature T n parameters were determined using the Westcott formalism. 176Lu was used as non- 1/ν monitor while 197Au, 96Zr and 94Zr were used as 1/ν monitors. The average values of $$ r(\alpha )\sqrt {T_{n} /T_{0} } ,\,g_{Lu} (T_{n} ) $$ and T n were determined to be 0.1795 ± 0.0044, 1.9729 ± 0.0234 and 50.12 ± 3.21°C, respectively. The accuracy of the method was evaluated by analysing IAEA-Soil 7, IAEA-SL 1, NBS SRM 1633A-1 and IAEA-Soil 375 as reference materials. The results show an acceptable level of consistency.

Characterization of serpentine: a potential nuclear shielding material

The use of serpentine as a potential nuclear shielding material necessitates a chemical quality control of the samples before its use in reactors. With this in view, characterization of these mineral samples was carried out using inductively coupled plasma atomic emission spectrometry (ICP-AES) and Instrumental neutron activation analysis (INAA) methods. The analytical results obtained by both ICP-AES and NAA techniques were found to be comparable. Na, Cr, Co, Zn, and Cu were found to be present in all samples of Indian origin while Ga, Ag, Ni, and Cd were found to below the limits of detection. A comparison on the detection limits of elements of interest was also carried out by both the analytical techniques and found to be in good agreement. An infrared spectroscopic investigation was also carried out on all the mineral samples. Bands at 3,689 and 3,648 cm−1 were attributed to inner and outer hydroxyl stretching of Mg–OH, respectively. The weak and broad band centered around 3,416 cm−1 was assigned due to the stretching vibrations of the adsorbed water molecules while three bands at 1076, 1022 and 968 cm−1 were prescribed to the vibrations of the SiO4 tetrahedra.

Hybrid NAA for study of organic halogens in precipitation in Beijing, China

Abstract The rainwater samples were collected from Beijing, China, from May 2006 to November 2007 and measured by a hybrid neutron activation analysis (NAA) method combining with gas chromatography (GC) for the concentrations and distribution of extractable persistent organic halogens (EPOX = EPOCl + EPOBr + EPOI), polychlorinated biphenyls (PCBs) and organochlorinated pesticides (OCPs). The average concentrations of EPOCl, EPOBr and EPOI in all the samples were 102, 0.18, and 0.31 μg/L, respectively. The relative proportions of the known organochlorines (84 PCB congeners + 10 OCPs) to total EPOCl were 0.03–1.44%, which implied that most of EPOCl measured in rainwater were unidentified. Significant correlations between the logarithms of the concentrations of EPOCl and EPOBr (r = 0.65, p < 0.0001) or EPOI (r = 0.72, p < 0.0001) and between the concentrations of EPOBr and EPOI (r = 0.79, p < 0.0001) were observed, which suggested that EPOCl, EPOBr and EPOI in rainwater might mainly come from the similar sources. There were no clear seasonal trends for the concentrations of EPOX. PCBs in rainwater were dominated by tetra-CB and tri-CB. The homologue was consistent with the technical PCB products in China, which indicated that PCBs in the environment mainly came from the historical usage of technical PCB products.

Development of a technique using MCNPX code for determination of nitrogen content of explosive materials using prompt gamma neutron activation analysis method

Abstract Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma 10.8 MeV following radioactive neutron capture by 14 N nuclei. We aimed to study the feasibility of using field-portable prompt gamma neutron activation analysis (PGNAA) along with improved nuclear equipment to detect and identify explosives, illicit substances or landmines. A 252 Cf radio-isotopic source was embedded in a cylinder made of high-density polyethylene (HDPE) and the cylinder was then placed in another cylindrical container filled with water. Measurements were performed on high nitrogen content compounds such as melamine ( C 3 H 6 N 6 ) . Melamine powder in a HDPE bottle was placed underneath the vessel containing water and the neutron source. Gamma rays were detected using two NaI(Tl) crystals. The results were simulated with MCNP4c code calculations. The theoretical calculations and experimental measurements were in good agreement indicating that this method can be used for detection of explosives and illicit drugs.

Heavy metals assessment in the hair of street children by INAA method, Isfahan

The street children phenomenon is an increasing problem in most cities of the world including Isfahan, which is a fast growing town. The number of street children with the growth of the town is increased. It is therefore important to have baseline data on their health problems. Hair element analysis remains an important tool in the nutritional and environmental assessment of them. A measurement of the elemental concentration in recently-grown hair provides an integrated view of the element status in the follicular cells and their blood supply, unaffected by short term fluctuations in the nutrient intake of the subject. This study aimed to assess heavy metals concentrations in the hair of street children in Isfahan using neutron activation analysis method. The concentration of heavy metals (Cu, Cr, Fe, Hg, Mn, and Zn) of 17 Iranian street children (Isfahan) was examined. Data analysis found that different profiles of the concentrations of Cr, Hg, Mn, and Zn were seen in each sample. These results were discussed with reference to show of environmental effects.

Concentrations of trace elements in livers of the Great Egret (Ardea alba) from the metropolitan region of São Paulo, SP, Brazil

The determinations of trace elements in tissues of herons are of great interest in order to evaluate envi- ronmental contamination. As the herons are at the top of the food chain they tend to accumulate high concentrations of contaminants in their tissues. Besides, the effects of pollution are also severe for this species, endangering the survival and reproduction of bird populations. In the present study, concentrations of the trace elements Br, Co, Cs, Fe, Rb, Se, and Zn were determined in livers from Great Egret (Ardea alba) species. The liver samples were those obtained from the adult specimens found dead in the metropolitan region of Sao Paulo, SP, Brazil. The liver samples were ground, freeze-dried and the elements were determined by the method of neutron activation analysis. The elemental concentration obtained in livers of these species showed wide variations depending on the element. Comparisons made between our results with literature data indicated that element concentrations obtained for herons from metropolitan region of Sao Paulo are higher or at the same order of magnitude of those obtained for specimens from polluted areas. Comparisons made between the results obtained for different genders of herons by applying non- parametric Mann-Whitney U test at the significance level of 0.05 indicated that female herons present Co and Se concentrations lower than those from males.

A combined method of neutron activation analysis and radiometric measurements for 234U and 238U determination in soil samples of low uranium concentration

A method that combines the use of non-destructive neutron activation analysis and high-resolution α spectrometry has been developed for determination of the activities of 234U and 238U in geological samples of low uranium content. The 238U content is determined by k0-based neutron activation analysis, whereas the 234U/238U relationship is measured by α spectrometry after isolation and electrodeposition of the uranium extracted from a lixiviation with 6 M HCl. The main advantage of the method is the simplicity of the chemical operations, including the fact that the steps destined to assure similar chemical state for the tracer and the uranium species present in the sample are not necessary. The method was applied to soil samples from sites of the North Peru Coast. Uranium concentration range 3–40 mg/kg and the isotopic composition correspond to natural uranium, with about 10% uncertainty.

Undergraduate research opportunities in neutron activation analysis for local, regional and international students

Neutron activation analysis (NAA) remains an excellent technique to introduce undergraduate students to nuclear science and engineering coming from different academic areas. The NAA methods encompass an appreciation of basic reactor engineering concepts, radiation safety, nuclear instrumentation and data analysis. At the Nuclear Engineering Teaching Lab at the University of Texas at Austin we have continued to provide opportunities through outreach programs to Huston-Tillotson University in Austin and Florida Memorial University in Miami Gardens, both Historically Black Colleges and Universities, and Southwestern University in Georgetown, Texas. Furthermore, in the past four years we have established a strong educational collaboration with the Ecole Nationale Superieure d’Ingenieurs de Caen (ENSICAEN), France. Undergraduate students at ENSICAEN are required to have an internship outside of France. While many of the students stay in neighboring European countries others have chosen the United States. The cornerstone of these programs is to secure a relationship with each institution through clear educational and research objectives and goals.

Neutron activation analysis of concrete for cross-border nuclear security

The dissolution of the Soviet Union coupled with the growing sophistication of international terror organizations has brought about a desire to ensure that a sound infrastructure exists to interdict smuggled nuclear material prior to leaving its country of origin. To combat the threat of nuclear trafficking, radiation portal monitors (RPMs) are deployed around the world to intercept illicit material while in transit by passively detecting gamma and neutron radiation. Portal monitors in some locations have reported abnormally high background counts. The higher background data has been attributed, in part, to the naturally occurring radioactive materials (NORM) in the concrete surrounding the portal monitors. Higher background increases the minimum detectable activity (MDA) and can ultimately lead to more material passing through the RPMs undetected. This work employed two different neutron activation analysis (NAA) methods for the purpose of developing a process to characterize the concrete surrounding the RPMs. Thermal neutron instrumental NAA (INAA) and fast NAA (FNAA) were conducted on six samples from three different composition concrete slabs. Comparator standards and quality control materials were used to help ensure that the methods were both precise and accurate. The combination of INAA and FNAA accounted for 84–100% of the total elemental composition of the samples. Knowing the composition of the concrete will allow RPM customers to choose suitable materials prior to installation, thereby increasing the ability of the monitors to detect radiological and nuclear materials.

A radiochemical method for neutron activation analysis of arsenic in biological samples and its potential use in epidemiology studies

Epidemiology studies that examine As toxicity rely on the accurate measurement of As in biological matrices to determine exposure. Accurate measurement of As in biological matrices is challenging by instrumental NAA due to the production of high and variable activities of 24Na, 122Sb and 82Br which contribute to increased background and difficulty quantifying the 76As peak at 559 keV. This paper describes a novel radiochemical NAA method for As analysis in biological matrices. Samples were irradiated at the University of Missouri Research Reactor in a flux of 6.5E + 13 n/cm2/s. Following irradiation samples were transferred to polypropylene tubes with As carrier and digested using a combination of nitric acid and hydrogen peroxide. Arsenic was separated by absorption on magnetite nanocyrstals followed by vacuum filtration. Samples were counted using an automated sample changer and HPGe detector with a Canberra Lynx digital signal analyzer. The accuracy and precision of the RNAA results were evaluated by measuring As in NIST SRM 1575 Pine Needles, 1571 Orchard Leaves, 1566 Oyster Tissue, 1577 Bovine Liver, and NCS DC 73347 Hair. Arsenic was measured in duplicate nail samples by instrumental neutron activation analysis followed by radiochemical neutron activation analysis.

DETERMINATION OF CONTENT OF SOME ELEMENTS IN THE HUMAN BLOOD BY METHOD OF INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS USING DALAT NUCLEAR REACTOR

Neutron activation analysis using nuclear reactor has been used widely to determine of content of elements in environment, biology, geology, archaeology, etc. In this report, determination of content of some elements in the human blood by method of instrumental neutron activation analysis using Dalat nuclear reactor coupled with processing of results by k-zero method (using k0-Dalat code) and by relative one (using standard samples) is presented. 50 samples of the human blood are mainly collected from public objects in Lamdong province. They are prepared and activated together with the standard samples at the dry channel No. 7-1 and the rotary specimen rack (wet channel) of the reactor. Then they are directly measured by the HPGe gamma spectrometer and the measured data are processed. The experimental results for determination of ranges of contents and average values for 8 elements respectively are Na (1.06 - 2,48; 1.71 ± 0.30 mg/ml), Cl (1.10 - 3.75; 2.66 ± 0.71 mg/ml), Fe (0.26 - 0.72; 0.49 ± 0.09 mg/ml), K (0.31 - 1.14; 0.73 ± 0.15 mg/ml), Zn (4.55 - 13.97; 8.08 ± 1.24 μg/ml), Rb (2.73 - 7.92; 5.11 ± 0.86 μg/ml), Se (0.04 - 0.18; 0.08 ± 0.03 μg/ml) and Sc (0.22 – 1.61; 0.56 ± 0.24 ng/ml). Besides, content of sodium to be determined by the k-zero method and the relative one are compared also. The results for determination of contents of 8 elements in the human samples to be compared with those of other authers are shown that this method has had confidence, and it could be applied routinely in determination of contents of multi-elements.

Evaluation of Radiochemical Neutron Activation Analysis Methods for Determination of Arsenic in Biological Materials

Radiochemical neutron activation analysis (RNAA) with retention on hydrated manganese dioxide (HMD) has played a key role in the certification of As in biological materials at NIST. Although this method provides very high and reproducible yields and detection limits at low microgram/kilogram levels, counting geometry uncertainties may arise from unequal distribution of As in the HMD, and arsenic detection limits may not be optimal due to significant retention of other elements. An alternate RNAA procedure with separation of arsenic by solvent extraction has been investigated. After digestion of samples in nitric and perchloric acids, As(III) is extracted from 2 M sulfuric acid solution into a solution of zinc diethyldithiocarbamate in chloroform. Counting of (76)As allows quantitation of arsenic. Addition of an (77)As tracer solution prior to dissolution allows correction for chemical yield and counting geometries, further improving reproducibility. The HMD and solvent extraction procedures for arsenic were compared through analysis of SRMs 1577c (bovine liver), 1547 (peach leaves), and 1575a (pine needles). Both methods gave As results in agreement with certified values with comparable reproducibility. However, the solvent extraction method yields a factor of 3 improvement in detection limits and is less time-consuming than the HMD method. The new method shows great promise for use in As certification in reference materials.

Analysis of large and non-standard geometry samples of ancient potteries by internal monostandard neutron activation analysis using in situ detection efficiency

The k 0-based internal monostandard neutron activation analysis (IM-NAA) method was used for the analysis of 30 large and non-standard geometry ancient pottery samples obtained from Buddhist sites of Andhra Pradesh, India. One freshly finished pottery and a sun-drenched pottery were also analyzed for comparison. Samples were irradiated in thermal column facility of Apsara reactor and also in graphite reflector position of critical facility of Bhabha Atomic Research Centre. Radioactive assay was carried out using a 40% relative efficiency HPGe detector coupled to MCA. Concentration ratios of 15 elements with respect to Sc were determined. The La/Ce values as well as statistical cluster analysis utilizing concentration ratios of elements were used for grouping/provenance of the potteries.

Analysis of Arsenic Concentrations and Correlation in Water, Soil and Aurum by Neutron Activation Analysis Technique: A Case Study in Bagerhat, Bangladesh

Arsenic concentrations were measured in water, soil and arum (vegetables) samples using the Neutron Activation Analysis method and a correlation between arsenic concentrations in the samples was investigated. The case study at Bagerhat, Bangladesh revealed that almost all the water samples were contaminated by a hazardous level of arsenic that exceeding the World Health Organization recommended value of 0.05 mg/L for Bangladesh. Arsenic concentration of all the water samples ranged from 0.09 to 0.87 mg/L. The concentrations in soil and aurum samples were found to be in the range of 2.22-35.21 and 0.07-0.73 mg/kg, respectively. A positive correlation between arsenic concentrations in soil and water samples was observed. Aurum sample was found to be contaminated by arsenic to a harmful level if the corresponding water sample was also highly contaminated.

Determination of arsenic (III) and arsenic (V) in freshwater biological samples from Thailand by solvent extraction and neutron activation

Neutron activation analysis (NAA) methods were employed for the determination of total arsenic, and water soluble As(III) and As(V) compounds in freshwater fish/shellfish and plant samples from Southern Thailand. Total arsenic concentrations varied from 0.05 to 425 mg kg−1. Water soluble arsenic species were separated by solvent extraction using ammonium pyrrolidinedithiocarbamate (APDC)/methylisobutylketone (MIBK) followed by NAA. The water soluble As(III) and As(V) levels varied from 0.07 to 26.4 and 0.03 to 22.9 mg kg−1, respectively. The As(III) and As(V) detection limits were 0.007 for fish/shellfish, 0.005 for As(III) and 0.006 mg kg−1 for As(V) in plants. This separation method allows for the determination of water soluble As(III) and As(V) using commonly available and inexpensive laboratory equipment and chemicals, which can be coupled to a variety of quantification techniques.

YOGYAKARTA AIR BORNE QUALITY BASED ON THE LEAD PARTICULATE CONCENTRATION

Analysis of Yogyakarta air quality based on concentration of lead particulate using Fast Neutron Activation Analysis (FNAA) method has been done. The sample was taken 3 times in 16 strategic locations of Yogyakarta city using Hi-Vol air sampler that equipped with cellulose filter TFA 2133. The sample irradiated for 30 min with 14 MeV fast neutron and then counted using gamma spectroscopy (AccuSpec). The result indicated that concentration of Pb-208 along Diponegoro street up to Janti street respectively are minimally (0.689 - 0.775) mg/m3, and maximally: (1.598 - 1.785) mg/m3. According to DIY governor decree No. 153/2002 about the limited toxicity ambient on Yogyakarta area it is concentration that Pb. The concentration of Pb-208 are still below the permitted value of 2 mg/m3, but in certain areas, the Pb concentration is almost equal to upper limit of permitted concentration of Pb. Keywords: air borne, neutron generator, FNAA