• Journal of Korean Society of Environmental Engineers
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• v.30 no.11
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• pp.1123-1131
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• 2008

In this study, measurement uncertainty of instrumental neutron activation analysis was evaluated for ambient As concentration in PM2.5. Expanded uncertainties of the measurements were calculated by applying both ISO-GUM approximation and Monte Carlo Simulation(MCS). The estimate of As concentration on a specific day by the Monte Carlo Simulation differed from that of ISO-GUM approximation by less than 4%. Relative expanded uncertainties of As concentrations from a total number of 60 PM2.5 samples were also estimated to be more or less than 10% with 95% confidence level using the Monte Carlo Simulation. Sensitivity test of the measurement uncertainties showed that $\gamma$-ray counting error(62.3%), efficiency(18.5%), air volume(12.3%), neutron flux(2.3%), and absolute gamma-intensity(1.8%) are major factors of uncertainty variations.

• Journal of Korean Traditional Oncology
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• v.16 no.1
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• pp.41-53
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• 2011

Background and Objectives: Iodine is an essential constituent of the thyroid hormones associated with the growth and development of humans and animals as an inorganic nutrition. This element may be accumulated in human blood, tissues and body through the intake of foodstuffs, a beverage, a nutritional supplement and a medicine, among others. The aim of the research is to find out a better medicinal stuff for the thyroid cancer patient who required a low level of iodine diet. Methods: Neutron activation analysis (NAA) used for the iodine analysis is one of nuclear analytical techniques using radiation and radioisotopes and very useful as sensitive analytical technique for performing both qualitative and quantitative multi-elemental non-destructive analysis of major, minor and trace components in variety of environmental and biological materials. In this study, iodine contents in ten kinds of oriental herb medicinal products, which is frequently used to cancer patients are determined by using instrumental neutron activation analysis (INAA) at the HANARO research reactor. The samples prescribed are manufactured as powdered form for taking medicine easily. The analytical quality control is performed to assure an uncertainty of the measurement and to compensate the measured data using a biological certified reference material, NIST SRM 1572, Citrus Leaves. The measured value is $1.89{\pm}0.35mg/kg$, and the relative error is 2.88%, and relative standard deviation is 19 % due to high counting error by small counts of gamma ray spectrum. The standard deviations for other elements such as Cl, K, Mn and Na were in the range of 2 to 8%. Result: The level of iodine contents of Biki-huan, Chungryong-huan and Chungcho-huan, samples detected is less than 6 mg/kg except Hangam Plus sample (more than 210 mg/kg) and six samples were not detected. Iodine in the samples of Shoxiho-tang, Shopunghualhyl-tang, Shocungryong-tang, Banhasaxim-tang, Insampaedox-san and Myunyuk Plus were not measured, but possible level of content can be estimated from the detection limits. In addition, the concentrations of some major elements like Cl, K, Mn, Na, in the samples were determined with the detection limits. Conclusions: Most of samples showed low iodine contents of less than 6 mg/kg but it turned out that most of testing samples can be used to classify the level of iodine diet samples considering the recommended low level of iodine diet 50 ${\mu}g$/day, and a better medicinal stuff for the thyroid cancer patient can be found.

• Nuclear Engineering and Technology
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• v.49 no.3
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• pp.562-568
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• 2017

Background: The chemical characterization of metallic alloys and oxides is conventionally carried out by wet chemical analytical methods and/or instrumental methods. Instrumental neutron activation analysis (INAA) is capable of analyzing samples nondestructively. As a part of a chemical quality control exercise, Zircaloys 2 and 4, nimonic alloy, and zirconium oxide samples were analyzed by two INAA methods. The samples of alloys and oxides were also analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) and direct current Arc OES methods, respectively, for quality assurance purposes. The samples are important in various fields including nuclear technology. Methods: Samples were neutron irradiated using nuclear reactors, and the radioactive assay was carried out using high-resolution gamma-ray spectrometry. Major to trace mass fractions were determined using both relative and internal monostandard (IM) NAA methods as well as OES methods. Results: In the case of alloys, compositional analyses as well as concentrations of some trace elements were determined, whereas in the case of zirconium oxides, six trace elements were determined. For method validation, British Chemical Standard (BCS)-certified reference material 310/1 (a nimonic alloy) was analyzed using both relative INAA and IM-NAA methods. Conclusion: The results showed that IM-NAA and relative INAA methods can be used for nondestructive chemical quality control of alloys and oxide samples.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1330-1338
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• 2024

Information on isotopic composition and geometric structure is necessary for identifying a true warhead. Nevertheless, such classified information should be protected physically or electronically. With a novel Hash encryption algorithm, this paper presents a Monte Carlo-based design of a neutron activation analysis verification module. The verification module employs a thermal neutron source, a non-uniform mask (physically encrypting information about isotopic composition and geometric structure), a gamma detector array, and a Hash encryption algorithm (for electronic encryption). In the physical field, a non-uniform mask is designed to distort the characteristic gamma rays emitted by the inspected item. Furthermore, as part of the Hash algorithm, a key is introduced to encrypt the data and improve the system resolution through electronic design. In order to quantify the difference between items, Hamming distance is used, which allows data encryption and analysis simultaneously. Simulated inspections of simple objects are used to quantify system performance. It is demonstrated that the method retains superior resolution even with 1% noise level. And the performances of anti-statistical attack and anti-brute force cracking are evaluated and found to be very excellent. The verification method lays a solid foundation for nuclear disarmament verification in the upcoming era.

• Journal of Nutrition and Health
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• v.31 no.2
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• pp.213-219
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• 1998

This study was conducted to compare and evaluate the iodide specific ion electrode method (ISE) and neutron activation analysis method (NAA) for determining iodine in human milk and cow milk. The neutron irradiation and counting operations were carried out at the TRIGA Mark-III reactor facility of the Korea Atomic Energy Research Institute. The mean concentrations of iodine in human milk samples by the ISE and the NAA were 1450$\mu\textrm{g}$/L and 1350$\mu\textrm{g}$/L, respectively. The levels were not significantly different. In cow milk samples , the mean concentrations of iodine by the ISE and the NAA were 250$\mu\textrm{g}$.L and 200$\mu\textrm{g}$/L, respectively. here, the ISE reading was significantly higher than the NAA. reading. The correlations of the two methods were 0.92(p<0.001) for human milk samples and 0.65 for cow milk samples . The coefficient of variation was 8.3% in the ISE and 4.9% in the NAA. Therefore, the iodide specific ion electrode method is sample and fast method, but probably not in processed milk since free sulfhydryl groups in milk are also detected by the iodide electrode. However, these also indicate that the ISE method may be applicable to human milk and pasteurized milk if the conventional pasteurization time-temperature relationship of standards is not exceeded. On the other hand, the NAA method , which is independent of chemical forms and matrix, can be used for determining iodine in all kinds of milk and foods.

• Journal of Conservation Science
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• v.21
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• pp.89-100
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• 2007

This study analyze concentration of minor and trace elements on 47 white porcelains excavated from Dudong-ri, Baekryeon-ri, Sachon-ri kilns in Gyeonsangnam-do by NAA(neutron activation analysis) and try to classify the provenance and characteristics according to the analytical result. Each kilns are divided into the group by PCA(principal component analysis) and LDA(linear discrimination analysis) using 17 elements; Ba Ce, Co, Cr, Cs, Dy, Eu, Hf, La Lu, Rb, Sc, Sm, Ta, Th, V, Yb. The contribution elements are Dy, Sm, La, Ce, Lu, Sc. And soft and hard white porcelains are similar with the chemical composition of the use materials therefore the difference of the chemical composition not confirmed a cause. The analytical results of the fine(I) and poor(II) quality white porcelains presume the difference of the povenance of clay materials or the poduction process such as difference purify and additive materials.

• Analytical Science and Technology
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• v.17 no.4
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• pp.308-314
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• 2004

When the polymer was used for the guard raw materials of electronic device, the content of U, Th and their daughter nuclides were known as a factor of soft error. Because emitted alpha ray could be caused of mis-operation. And ionic impurities such as Cl, Fe, Na could shorten the device life-time. For the analysis of trace impurities in the polymer, neutron activation analysis(NAA) and ICP/AES have been studied. To improve the accuracy and sensitivity of the trace and ultratrace metallic impurities in the epoxy and phenol polymer, sample pretreatment method and optimum analytical condition of NAA were developed. Using the above method, U, Th and other 23 trace impurity elements were analyzed.

• Analytical Science and Technology
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• v.14 no.4
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• pp.1075-1081
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• 2001

Instrumental Neutron Activation Analysis as a representative method of nuclear analytical technique, has advantages of non-destructive, simultaneous multi-element analysis with the characteristics of absolute measurement method. Up to date, $k_0$-quantitative method which is accurate, convenient and user-friendly, has been generalized world-widely. In this study, it is intented to introduce the general concept of $k_0$-method and to measure $k_0$-parameters for the future implementation to our NAA system. For this objectives, the definition of relevant factors for the quantitative analysis and the equation for the experimental determination of parameters such as $Q_0$(${\alpha}$) and f were summarized. Furthermore, a foundation for the $k_0$-standardization method was prepared through the measurement of ${\alpha}$ and f-value which depend on the specific character of irradiation hole at NAA#1-hole of HANARO research reactor.

• Nuclear Engineering and Technology
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• v.12 no.1
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• pp.29-38
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• 1980

A radiochemical separation scheme for the neutron activation analysis is developed for the determination of 28 elements in aluminum. The scheme is based on a group separation using ion-exchange resin and mineral exchanger. Present work has employed mineral acids and their partly organic mixture excluding HF as the media as well as common glass wares. For the determination, gamma-ray spectroscopy using $3"\times3"\;Nal(TI)$ detector and a single comparator method are used.

• Nuclear Engineering and Technology
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• v.13 no.4
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• pp.237-244
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• 1981

The preliminary concentration of trace elements in uranium dioxide using an anion exchange resin is presented for neutron activation analysis. The uranyl solution in sulfuric acid is adjusted to the acidity of about pH 2.7 and loaded on a column of the anion exchange resin. An appropriate volume of eluates obtained from the column shows good recoveries of trace elements. By combining this preconcentration with a radiochemical separation scheme, which was developed for the determinations of impurities in aluminum, it is possible to determine 21 trace elements in reactor grade uranium dioxide.