Determination of cobalt by substoichiometric thermal neutron activation analysis

A selective method has been developed for the determination of traces of cobalt in different matrices by the sensitive technique of thermal neutron activation analysis employing radiochemical separation and substoichiometric extraction of Co/II/ with iso-nitrosobenzoylacetone into chloroform.     

Determination of cadmium by substoichiometric thermal neutron activation analysis

A rapid and selective method has been developed for the determination of cadmium in environmental samples by thermal neutron activation analysis, employing substoichiometric solvent extraction technique. Alcoholic solution of 2-mercaptobenzothiazole /2-HMBT/ has been used for the substoichiometric extraction of Cd/II/ from an aqueous solution of pH 7.0 into methyl iso-butyl ketone /MIBK/.     

Determination of palladium by chemical neutron activation analysis using low energy photon spectrometry

A chemical neutron activation analysis method to determine trace amounts of palladium present in the uranium ores has been developed. Palladium was concentrated on an anionic exchanger to purify from large amounts of uranium, iron and copper that were present in the ore. The resin in which Pd was adsorbed was neutron irradiated and the activation product¹⁰⁹Pd was assayed through its daughter^109mAg by low energy photon spectrometry to estimate palladium. Both the 88 keV gamma-line and the 22 keV X-ray line (arising out of the internal transition of^109mAg) were used to arrive at the concentration values by a standard comparison technique. A thin window Si(Li) detector and an HPGe detector were used for the radioactive assay. Detection limits and the advantage of using the X-ray line of Ag over that of the gamma-line were discussed. An absolute detection limit of 0.12·10⁻⁹ g could be arrived at by the use of the 22.10 keV X-ray line in an interference-free condition.     

Determination of trace impurities in rhodium metal by destructive and non-destructive neutron activation analysis

Trace amounts of Ir, Au, Cu, Pd and Pt were determined in rhodium metal by instrumental neutron activation analysis with Ge(Li) spectrometry as well as by the radiochemical version of the method. The latter was based on a specially developed procedure of the dissolution of Rh, followed by group separation with the aid of ion exchange chromatography. The results obtained by destructive and non-destructive methods are critically discussed and compared. Special attention was paid to self-shielding effect and an accurate method of the correction of this effect is presented.     

Determination of carrier yields for neutron activation analysis using energy dispersive X-ray spectrometry

A new method is described for determining carrier yield in the radiochemical neutron activation analysis of rare-earth elements in silicate rocks by group separation. The method involves the determination of the rare-earth elements present in the carrier by means of energy-dispersive X-ray fluorescence analysis, eliminating the need to re-irradiate samples in a nuclear reactor after the gamma ray analysis is complete. Results from the analysis of USGS standards AGV-1 and BCR-1 compare favorably with those obtained using the conventional method.     

Determination of k-factors by thermal neutron activation technique

The k_{o, Au}-factors of 10 elements have been determined by irradating the samples with thermal neutrons in the reactor thermal column. The proposed method has the advantage of eliminating the errors induced by the uncertainties of the neutron spectrum parameters and the nuclear data. The results obtained are in good agreement with the literature data.     

Determination of uranium by neutron activation analysis using substoichiometric separation

Three analytical methods for uranium by neutron activation are described. The methods are based on the substoichiometric separation of barium or lanthanum, which are the fission products of uranium-235 by neutron irradiation. Uranium contents in high purity materials were determined by the methods, which were found to be useful for the determination of a trace amounts of uranium.     

Determination of antimony in nail and hair by thermal neutron activation analysis

The concentration of antimony in nail and hair was determined by thermal neutron activation analysis. Samples were collected from the workers of an antimony refinery, inhabitants near the refinery, and residents in control area. They were irradiated by Kyoto University 5 000 kW Reactor for 1 h, and cooled for 30 to 100 days. After cooling, the concentration of Sb in nail and hair was estimated by measuring the intensity of gamma-ray from 124Sb of the samples, then the samples were washed by 0.1% aqueous solution of nonionic surface active agent in an ultrasonic cleaner. The gamma-ray spectrometry was done again (after washing). The concentration of Sb in nail before washing was 730 ppm for the workers, 2.46 ppm for habitants near the refinery, and 0.19 ppm for the control; after washing, it became 230 ppm for the workers, 0.63 ppm for habitants, and 0.09 ppm for the control. The concentration of Sb in hair before and after washing was 222 ppm and 196 ppm for the workers, and 0.21 ppm and 0.15 ppm for the control, respectively.     

Determination of Sc in rock samples by substoichiometric thermal neutron activation analysis

A rapid, selective and simple method has been developed for the determination of Sc in rock samples by thermal neutron activation analysis, employing substoichiometric solvent extraction of Sc(III) with alizarin into 1-octanol. Two samples and a standard can be processed and counted within three hours.     

Determination of chromium in aquatic environment by substoichiometric thermal neutron activation analysis

Chromium has been determined in environmental samples. The method described here involves the irradiation of environmental samples and a g quantity of standard with thermal neutrons at the self-serve position in the CIRUS reactor, followed by dissolution of the sample and standard in the presence of a milligram amount of carrier. Both the sample and the standard are subjected to substoichiometric extraction under controlled experimental conditions with alizarin into cyclohexane. An aliquot of the organic phase was counted on a gamma-ray spectrometer. The concentration of Cr in water samples from Bombay and Karad City, and the accuracy, precision and sensitivity of the method are discussed.     

Determination of cadmium using radiochemical neutron activation analysis

A method has been developed for the determination of cadmium in samples of food and biological materials using neutron activation analysis with radiochemical separation. The irradiated sample is digested in presence of cadmium carrier, with a nitric-perchloric mixture, evaporated to dryness, dissolved in 6M HCl and placed onto an ion exchange column loaded with Dowex 1-X8 resin in chloride form and conditioned with HCl 6M. The cadmium is retained in the resin. After a washing procedure with several portions of HCl of decreasing concentration, the cadmium is eluted with an ammonia-ammonium chloride buffer. The activity of ^115mIn which is in equilibrium with ¹¹⁵Cd, is measured using a NaI(Tl) well type detector. The method has been evaluated by analyzing certified reference materials with cadmium concentrations covering a range of 0.020 to 200 mg^.kg^-1. The agreement of the results with the certified values is within 95%, which gives an indication of the sensitivity and accuracy of the proposed method.     

Determination of silicon in iron by thermal neutron activation

A new chemical separation procedure for the determination of silicon in iron after neutron activation was developed. It uses two separation steps, one on a cation exchange resin in HCl−HF-acetone medium, and the other on alumina at pH 9. The detection limit for silicon was 0.02 μg. This analytical procedure was applied to the control of the zone-melting purification of iron.     

Determination of silicon in metals by thermal neutron activation

A new method of silicon determination in molybdenum by the³⁰Si(n, γ)³¹Si was developed. All the problems occurring during this analysis: standardization, quantitative dissolution, silicon sorption on vessels, reproducibility of β-counting...were carefully studied and new answers were brought to them. The chemical speratation of silicon was performed with a column of anion exchange resin in HCl-HF-H₂O₂ solution and a column of alumina at pH 9. Accuracy and reproducibility were controlled on standard samples prepared by fusion of inactive molybdenum and radioactive silicon in a plasma furnace.     

Determination of palladium in alloys and ores by substoichiometric thermal neutron activation analysis

A rapid, selective and simple method have been developed for the determination of palladium in alloys and ores by thermal neutron activation analysis, incorporating substoichiometric solvent extraction of Pd/II/ with 1,2,3-benzotriazole /1,2,3-BT/ into methyl iso-butyl ketone /MIBK/. Two samples and a standard can be processed and counted within two hours.     

The determination of traces of iridium in rhodium by neutron activation analysis

Iridium traces were determined in rhodium by thermal neutron activation for 2 days at a flux of 4.10¹¹ n·cm^-2·sec^-1. After cooling for at least 1 week, the samples were analysed by γ-spectrometry. No radiochemical separations were required. Special attention was paid to self-absorption phenomena in the rhodium samples.     

Determination of characteristic neutron flux parameters of nuclear reactors for thermal neutron activation analysis

The characteristic neutron spectrum parameters for thermal neutron activation analysis have been determined for the most important irradiation positions of the reactors BR1 and BR2 at Mol (Belgium), HFR at Petten (Netherlands) and FRJ2 at Jülich (Federal Republic of Germany). The method of determination is described.     

Determination of silver using cyclic epithermal neutron activation analysis

A fast pneumatic transfer facility was installed in Nuclear Engineering Teaching Laboratory (NETL) of the University of Texas at Austin for the purpose of cyclic thermal and epithermal neutron activation analysis. In this study efforts were focused on the evaluation of cyclic epithermal neutron activation analysis (CENAA). Various NIST and CANMET certified materials were analyzed by the system. Experiment results showed ¹¹⁰Ag with its 25 s half-life as one of the isotopes favored by the system. Thus, the system was put into practical application in identifying silver in metallic ores. Comparison of sliver concentrations as determined by CENAA in CANMET certified reference materials gave very good results.     

Non-destructive determination of rhodium in platinum by epithermal reactor neutron activation analysis

Activation in connection with Ge(Li) γ-spectrometry proves profitable in determining traces of rhodium (and silver) in pure platinum. As the 556 keV photopeak of¹⁰⁴Rh was chosen for evaluation, its decay behaviour had to be considered. Moreover, a special automatic correction of dead-time and decay was applied. The limit of detection in a single run was 5 ppm.     

Determination of trace elements in various organs of rats by thermal neutron activation analysis

The trace element levels in various organs of normal rats have been determined by means of thermal neutron activation followed by high-resolution gamma-spectroscopy. Abundances for 11 elements (Cu, Mn, Fe, Zn, Rb, Sb, Se, Cr, Co, Cs and Sc) were evaluated in the individual subjects. The present results were generally found within the ranges of the literature values, except for ultra-trace elements. Reliability of the method was assessed by analyzing NBS standard reference materials, Orchard Leaves and Bovine Liver. The trace element contents of the rat diet have also been measured, and comparison of them with those of the rat organs was given.     

Determination of thallium in biological samples by thermal neutron activation analysis and low-level beta-counting

A procedure is described for the determination of thallium in complex biological matrices by thermal neutron activation analysis employing substoichiometric extraction of thallium(I) with 2-mercaptobenzothiazole (2-HMBT) at a pH of 7.5 into chloroform, and low-level beta-counting.