Determination of Platinum-Group Elements and Gold in Silicates by Gamma Activation Autoradiography and Instrumental Gamma Activation Analysis

The potential of the gamma activation determination of platinum-group elements and gold both by instrumental gamma activation analysis (bulk analysis) and by monitoring their distribution using autoradiography (local analysis) is studied. It is shown that platinum-group elements and gold can be determined by direct gamma-ray spectrometry in silicate samples with a detection limit of 10^–3–10^–5%. In contact gamma activation autoradiography, the detection limit for these elements is about 10 ng with a spatial resolution of 10–20 m.     

Instrumental Neutron Activation Analysis of Extractable

Instrumental neutron activation analysis was performed to measure the levels of extractable organohalogens (EOX) in the organisms from the Antarctic marine ecosystem. The results show that EOX (EOCl, EOBr and EOI) were found in all the samples analyzed. The highest concentration was determined in the ascidian sample. The concentration order of EOX was mainly EOCl>EOBr>EOI with the exception of nemertine, ascidian, fish and adelie penguin samples. The concentrations of man-made organochlorines (DDTs and CHLs) were analyzed by GC-MS, and the results were compared with the concentrations of EOX determined in the same samples. The results show that the contribution of known man-made organochlorines in EOCl was less than 3%. This means that a large amount of unknown organochlorine compounds is present in Antarctic marine organisms.     

仪器中子活化法测定金属钛中杂质元素

采用仪器中子活化法(INAA)测定了金属钛中锰、砷、锑、钽、钨等5种痕量杂质元素含量,分析中采用GEM 70P高纯锗γ谱仪及grammavision 32分析软件。经预处理的样品割成5mm×5mm×1mm大小的薄片,其质量约180mg,与标准一起置于反应堆中照射,中子通量为1.0×10~(13)cm~(-2)·s~(-1)。上述5种元素的探测下限依次为0.022,0.049,0.032,0.097,0.015μg。将方法用于分析水沉积物标准物质(GBW 07312),锰、钽、锑及钨4种元素的测定值与证书值相符。     

Determination of Heavy Metals as Environmental Pollutants: Use of Instrumental Neutron Activation Analysis

The simultaneous determination of heavy metals by instrumental neutron activation analysis (INAA) in some environmental samples have been considered. A new approach has been proposed to assess the potentialities and the most adequate use of INAA for each particular heavy metal.     

Determination of Tellurium by Instrumental Photon Activation Analysis

Abstract

Tellurium has been determined at milligram and submilligram levels in the presence of uranium by a strictly instrumental photon activation ¹²¹ analysis procedure. The 575 keV gamma ray of Te was measured. At a decay time of three weeks, this gamma ray peak was interference-free. As little as 0.4 mg of tellurium was determined and the method evidences that sensitivity would increase with irradiation time.     

Instrumental Neutron Activation Analysis for Certification of Ion-Implanted Arsenic in Silicon

Standard reference material (SRM) 2134 Arsenic Implant in Silicon was produced at the National Institute of Standards and Technology (NIST) as a calibrant for secondary ion mass spectrometry. Instrumental neutron activation analysis was used as a primary method for certification of the arsenic implanted dose. A complete evaluation of all sources of uncertainty yielded an expanded relative uncertainty for the mean value of this SRM to be 0.38% at approximately the 95% level of confidence. No evidence indicating significant heterogeneity among samples was observed.     

Instrumental Activation Analysis of Meteorites Using Gamma-Gamma Coincidence Spectrometry

Abstract

A non-destructive procedure for the determination of iridium, sodium, nickel, cobalt, and scandium in a single meteorite sample is presented. The method utilizes neutron activation followed by gamma-gamma coincidence spectrometry. Iridium abundances are given for several meteorites and compared to values obtained by radiochemical separation methods. The non-destructive results differ significantly from previously published values for certain classes of meteorites, in particular the enstatite chondrites.     

Design Features of a Prompt Gamma Neutron Activation Analysis System at HANARO

The design features are described of a prompt gamma neutron activation analysis system at HANARO, a 30 MW research reactor in the Korea Atomic Energy Research Institute. The beam consists of polychromatic thermal neutrons diffracted by a set of pyrolytic graphite crystals at orders n in the range 1n6 at a Bragg angle of 45° on a horizontal beam line. A neutron flux of 1.0·10⁸ n·cm^–2·s^–1 is calculated at the sample position from the reflectivity of the crystal which has been confirmed in a measurement of a diffracted neutron spectrum using a time-of-flight spectrometer and gold-wire activation. The fast neutron and gamma backgrounds will be low due to the use of a diffracted beam and a tapered collimator. The detection system comprises a 30% n-type HPGe detector, signal electronics and a fast ADC. The first application of this system will be the analysis of boron concentration in biological samples for neutron capture therapy. Construction of the beam line and the arrangement of the detection system is proceeding.     

Rapid Instrumental Nuclear Activation Analysis of Rocks,Cements and Meteorites

The experimental set-up and the method for γ-spectrum analysis as used in the activation analysis of rocks, cements and meteorites by reactor neutrons are discussed. Rapid nondestructive simultareous determination of several elements is possible. Fractional percent reproducibility is possible for Al, Na and Mn; the determination of Ca, Mg and V in the samples studied us influenced by the Al- and Mn-content, but reproducibility approaches 1% in favorable cases. Accuracy is generally within the limits set by the reproducibility. The minimum weight of the sample is small (10–40 mg), but the grain-size must be below 150 mesh; in the case of meteorites, a grain-size effect has been demonstrated. Representative results for several standard rocks and cements, for 7 L-chondrites, 2 hyperstene achondrites and separate mineral phases of the Elenovka chondrite are given.     

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.     

Prompt Gamma Activation Analysis with the Texas Cold Neutron Source

A Prompt Gamma Activation Analysis (PGAA) facility is being developed at The University of Texas at Austin (UT). The UT-PGAA facility will utilize a focused cold-neutron beam from the Texas Cold Neutron Source (TCNS). the TCNS consists of a cold source cryostat and a curved neutron guide. the use of a guided focused cold-neutron beam will provide a high capture reaction rate and low background. The UT-PGAA facility will be used in the nondestructive determination of B, Cd, Gd and S in biological and environmental samples.     

Precise Determination of Macrocontents by Instrumental Activation Analysis: Chances and Risks

Modern technology produces a large variety of organic, metallo-organic and inorganic compounds which might be analysed successfully for their stoichiometry by INAA or IPAA if the error sources are kept under control. The problems of comparator materials, irradiation by linear accelerator, measurement and data evaluation including minor corrections are dealt with. Application to TiCN, Si₃N₄, SiC and nitrogen determination in different carbonaceous materials is reported.     

南极岩石样品中稀土元素的中子活化分析

用仪器中子活化分析技术,测定了南极岩石中8种稀土元素含量,讨论了不同岩石的稀土模式特点。     

Determination of Trace Elements in Liquid Fuels by Instrumental Neutron Activation Analysis

Abstract

An instrumental neutron activation analysis with Ge(Li) γ -spectrometry and computer-assisted data reduction, has been developed for the determination of more than 20 elements in different liquid fuels. Organo-metallic standard solutions were mixed to obtain suitable standards. Two neutron irradiations and 4 γ-spectrometric measurements are required for each sample. Corrections were taken into account for a few spectrometric and nuclear interferences. The overall standard deviation for nearly all elements is mainly determined by counting statistics. The following elements can be determined : Na, Al, S, Cl, K, Sc, V, Cr, Fe, Co, Ni, Cu, Zn, As, Se, Br and La whereas the concentration of the following elements are mostly near the limit of detection: Mg, Mo, Sb, Ba, Th and Hg.     

Heavy metal determination in atmospheric particulate matter by Instrumental Neutron Activation Analysis

Instrumental Neutron Activation Analysis (INAA) is employed for its important analytical properties. Fundamentally, INAA is a multi-elemental technique allowing the determination of about 40 elements with a good Limit of Detection. In this paper we applied this nuclear technique to study the element composition in PM10 determining about 30 elements.25 filters were collected in downtown Rome from October 1999 to April 2000 and irradiated at the nuclear reactor Triga Mark II (ENEA-Casaccia Laboratories). The γ-ray measurements have allowed the quali- and quantitative analysis. The element levels in PM10 with the relative correlations have been determined: basically, the concentrations are very low.Furthermore, the enrichment factors of all elements will be reported in order to understand the natural or anthropogenic origins of the particulate matter: some elements may be attributed to long-range transport phenomena from other natural and/or anthropogenic sources.     

Determination of trace amounts of chlorine in hydraulic fluid by Instrumental Neutron Activation Analysis

A procedure has been developed for the determination by thermal neutron activation analysis of trace amounts of total chlorine in the Electro-Hydraulic-Control /EHC/ fluid used by the Hadera Power Station in various hydraulic systems. Irradiation for 1 min near the core of a nuclear reactor is followed by high resolution gamma-ray spectrometry using a Ge/Li/ detector. Chlorine amount is quantitatively determined by measuring the gamma-ray photopeaks of the radioactive nuclide³⁸Cl. The system response is linear in the concentration ranges investigated. Chlorine concentration in a fresh hydraulic fluid sample was found to be 17.6±0.5 ppm. The limit of detection, when assaying a 1 cm³ sample of fluid under the present experimental conditions, is 1 g of chlorine and the corresponding concentration is 1 ppm.     

人体子宫癌活组织中微量元素的中子活化分析

本文利用样品的低温干燥预处理技术和仪器中子活化分析方法,同时测定了人体子宫癌活组织中的29种微量元素,并分别与宫颈炎组织和正常组织比较,初步研究结果表明,子宫癌组织,宫颈炎组织和正常组织中Au,I,Se等微量元素有显著差异。     

中国先进研究堆瞬发γ元素成像技术研究

无损分析样品内部的元素分布,对于材料、考古、地质科学等领域的研究具有重要意义。本文基于瞬发γ活化分析方法,结合中子照相技术,分析了模拟样品的结构和对称性,首次利用中国先进研究堆(CARR)水平孔道聚焦的微束中子束流,开展了样品瞬发γ扫描分析和材料内部元素分布研究。通过蒙特卡罗软件(MCNP)对样品元素分布实验模型进行分析,模拟结果获得了样品不同区域的元素分布,基本实现了元素空间分辨。MCNP计算结果表明在瞬发γ扫描分析中,优化准直几何参数和提高中子通量能进一步提高元素空间分辨和元素测量准确度。     

Instrumental Neutron Activation Analysis of Trace Elements in Organs and Tissues of Zinc Deficient Mice

Eleven elements in ten organs and tissues of mice fed with Zn-deficient diet (Zn-def. mice) and those fed with control diet (control mice) were determined by INAA. Zinc concentrations in the organs of Zn-def. mice were not distinctly lower than those of control mice except for bone and pancreas, as similar to the predecessors' reported results. However, the Co content increased significantly in all the organs and tissues of Zn-def. mice compared with control mice. The organs and tissues observed were histologicaly normal and no typical symptoms of Zn deficiency disease were recognised. The results suggest that the change of Co-concentration may be regarded as a mark of the prestage for a Zn deficiency disease.     

Activation of Sintering of Zirconia Ceramics by Gamma Irradiation

It was studied how gamma irradiation affects the formation of the phase composition and the properties of ZrO₂-based ceramics containing various contents of Y₂O₃, which stabilizes the tetragonal ZrO₂ phase. Gamma irradiation favored sintering and a decrease in the content of the monoclinic ZrO₂ modification. At a sintering temperature of 1250°C, ZrO₂–3 mol % Y₂O₃ ceramic with a strength of 225 MPa was obtained; this strength is half as high again as that of ceramic synthesized without irradiation.