Determination of trace concentration of boron in ADU by the nuclear track technique

A method for the determination of boron concentration in extracted (NH₄)₂ U₂O₇·H₂O (ADU) has been used. One ml of the aqueous solution is irradiated with thermal neutrons from a 10 Ci Am/Be neutron source with a flux of 0.2·10⁵ n·cm^–2·s^–1 and thermal column in the IRT-5000 with a flux of about 10⁷ n·cm^–2·s^–1. The alpha-activity due to the reaction¹⁰B(n, )⁷Li is recorded by a CR-39 alpha track detector. After the exposure, the alpha tracks are made visible in an optical microscope at magnification of 800X by etching the detector in 6N NaOH, and the track density is determined using calibration curves of known concentrations of boron. The boron concentration of the extracted ADU was found to be 5 ppm.     

Application of an image scanner for determination of boron in glass by a nuclear track technique

For boron concentration in the range of 010%, a 600 g²⁵²Cf neutron source was used for thermal neutron irradiation. As for the track counting technique, a visual observation method by human eye and an automatic counting method with an image scanner showed a good agreement between the determinations by both methods. The latter is useful for improving accuracy in elemental determination by using the nuclear track technique because it gives reproducible count values which are free from human error in comparison with the former.     

Comparative analysis for boron in steel by ion microprobe mass analyzer and the nuclear track technique

The adsorption characteristics of Ba, Be, Cd, Mn, Pb and Zn on Pyrex, flint glass and polythene surfaces during storage under different conditions are described. It is concluded that the method of stabilization of water samples recommended by EPA, i.e. addition of 5 ml of 16 M HNO₃ per liter, is satisfactory. Stabilization and concentration with a mixed ligand system is recommended, except for Mn and Ba which are not extracted quantitatively. Extraction with APDC and MIBK is unsatisfactory for storage purposes.     

Determination of boron in glass by alpha-spectrometry

Alpha-spectrometric method has been used for the determination of boron in borosilicate glasses. For irradiation thermal neutrons with a flux of about 10⁵ n·cm^–2·s^–1, produced in a paraffin moderator surrounding a deuteron target of a small neutron generator, were used. Alpha-particles from the reaction¹⁰B(n, ) were detected by a Si solid state detector with a resolution of about 50 keV. The sensitivity of the method is 0.05 wt % boron in glass samples.This work was supported by the Hungarian Research Foundation (Contract No. 1734/91.).     

Lithium determination by the nuclear track technique

Résumé On utilise la technique traceur nucléaire pour doser le lithium dans le milieu biologique étalon 1571 (Feuilles végétales). Pour déterminer la concentration en lithium on compte les traces produites dans l'acétate de cellulose par les particules alpha issues du bombardement du lithium par des neutrons thermiques:⁶Li(n, α)³H.      

Determination of boron in nuclear materials by isotope dilution technique. Part I

Summary The application of the mass-spectrometric stable-isotope dilution technique for the determination of microgram and submicrogram quantities of boron in nuclear materials is described. An adequate amount of spike solution (enriched in¹⁰B) is added to the sample and the mixture is treated chemically to ensure isotopic equilibration. Boron is then separated as methyl borate by distillation from phosphoric acid and converted into sodium tetraborate suitable for isotopic analysis by surface ionization in a mass spectrometer. The results for boron content in a standard boric acid solution, reagents, ammonium diuranate, uranium dioxide, sintered pellets of UO₂ and uranyl nitrate are given. Owing to the simplicity, accuracy and high precision a possible application of the method would be its use for routine boron determinations in a natural uranium processing plant and/or as a standard method for intercomparison with other analytical methods.

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Zusammenfassung Die Anwendung der massenspektrometrischen Isotopenverdünnungsmethode auf die Borbestimmung im Bereich von Mikrogramm und darunter in Reaktormaterialien wurde beschrieben.Eine entsprechende Menge von angereichertem¹⁰B wird einer Probe zugegeben und die Mischung zur Herstellung des Isotopengleichgewichtes chemisch behandelt. Das Bor wird dann als Methylborat durch Destillation aus der phosphorsäurehaltigen Lösung abgetrennt und zum Zweck einer massenspektrometrischen Isotopenanalyse in Natriumtetraborat umgesetzt.Der Borgehalt in H₃BO₃-Standardlösungen, Reagenzien, Ammoniumdiuranat (ADU), UO₂, gesinterten UO₂-Pastillen und Uranylnitrat wird angegeben. Wegen der Einfachheit, Genauigkeit und Empfindlichkeit könnte diese Methode sowohl für die routinemäßige Borbestimmung bei der Herstellung von Brennstoffelementen mit natürlichem Uran als auch für die Standardisierung analytischer Methoden angewandt werden.

     

Determination of boron concentration in borosilicate glass,boron carbide and graphite samples by conventional wet-chemical and nuclear analytical methods

Boron is an important element in nuclear technology. A comparative study was carried out for the determination of boron in borosilicate glass, boron carbide and graphite samples by wet-chemical and nuclear analytical methods. Wet chemical methods namely titrimetry, Inductively Coupled Plasma Mass Spectrometry and ICP Optical Emission Spectrometry and nuclear analytical methods namely Particle Induced Gamma-Ray Emission and Nuclear Reaction Analysis were used. Boron concentrations were in trace (mg kg^?1) level in graphite and percentage level in borosilicate glass and boron carbide.     

Determination of boron in glass by neutron transmission method

Neutron transmission method has been used for the determination of boron in borosilicate glasses. The method is sensitive and rapid to control the spatial homogeneities of glass-product in the melting furnace.Dedicated to Academician J. Csikai on his 60th birthday.This work was supported by the National Foundation for Research (Contact No. 259).     

Determination of boron in steel by an ICP emission spectrometric technique

Summary A method was developed for the emission spectrometric determination of boron in steel using ICP excitation. Interfering effects of the matrix are avoided by pyrohydrolytic separation of boron. It is possible to determine boron from 1 mg/kg upwards.     

Determination of uranium concentration in water samples by the fission track registration technique

The fission track registration technique using Makrofol KG as detector and the wet method was developed for the determination of microgram amounts of uranium in water samples. This method allows the determination of uranium concentrations within the interval of 8.0 to 0.4 μg. U/l, the overall ranging from 3.3% to 29.0%. Results obtained for water samples from several sources in the State of São Paulo, Brasil, are reported.     

Determination of trace amounts of uranium in silicate minerals by the fission track technique

The fission track technique has been applied to the determination of uranium on Dowex 1 x 8 after chemical separation from silicates. Standard rock and several stone meteorite samples were treated by this method and satisfactory results were obtained. The procedure is applicable to natural waters.     

Determination of boron in iron-based metallic glasses by neutron irradiation and alpha-particle track recording in cellulose nitrate

A method for determination of the boron concentration in Fe−Ni−B metallic glasses has been developed. A solution of the alloy is irradiated with neutrons from a 10 μg²⁵²Cf neutron source and the alpha-activity due to the reaction¹⁰B(n, α)⁷Li is recorded by a cellulose nitrate alpha-track detector immersed in the solution. After the exposure the alpha-tracks are made visible in a microscope by etching the cellulose nitrate film in hot NaOH and the track density is determined.     

A study of lithium uptake and location in the brain using the nuclear track technique

The nuclear track technique was used to study the lithium uptake and location in the brains of rats. This study indicated that a maximum lithium concentration was reached in the brain eight hours after an intraperitoneal injection.     

Thoron interference in radon exhalation rate measured by solid state nuclear track detector based can technique

This paper presents the extent of thoron (²²⁰Rn) interference in the radon (²²²Rn) exhalation rate, measured by solid state nuclear track detector based ‘Can’ technique. Experiments were carried out following the standard procedure of ‘Can’ technique as well as active technique as a reference method for ²²²Rn and ²²⁰Rn exhalation measurements. It was found that ²²⁰Rn interference may lead to overestimation of ²²²Rn exhalation by a significant factor which can be as high as 12 depending upon the rate of ²²⁰Rn exhalation from samples.     

The use of solid-state nuclear track detection for the study of boron and fissile nuclide distributions in steel samples

The technique of boron autoradiography using cellulose acetobutyrate (CAB) film for measuring the distribution of boron in stainless steels, is described. The method involves the irradiation of the specimen and detector with thermal neutrons, and the development of the α-particle tracks arising from the nuclear reaction¹⁰B(n, α)⁷Li. A related technique for the measurement of fissile nuclides in steel hulls, is also described. In this case, a polycarbonate detector, Lexan, is used to detect the fission-particles from the thermal neutron fission of²³⁵U or²³⁹Pu, present in the surfaces of the specimens. The principles of the methods are described, and an outline of the techniques presented. The quantitative aspect of the method is considered and the results on various specimens discussed.     

Determination of boron by the neutron depth profile (NDP) technique for VLSI processing application

Borophosphosilicate glass (BPSG) has been used for its improved reflow properties compared to low temperature oxide (LTO) in planar technology. Thin films of BPSG were deposited by a low-pressure chemical vapor deposition process. The boron content was determined by NDP. In addition from the NDP spectrum the depth profile of boron and the thickness of the film were also determined. In the NDP technique, samples, typically silicon wafers with 500 nm thick BPSG film, were exposed to a highly-thermalized neutron beam. Generated by the¹⁰B(n,)⁷ Li reaction, isotropically emitted monoenergetic particles of 1.47 MeV were counted in an evacuated in-beam analysis setup. The energy loss of the -articles in the film was proportional to the depth at which the nuclear reaction took place. The energy spectrum of the -articles, therefore, was a direct result of the boron depth profile, and the area under the curve was a measure of the total number of boron atoms in the film. This unique nuclear technique provided an excellent method for optimizing the composition of the BPSG film for device processing.     

Determination of natural uranium in biological samples using the solid state nuclear track detector method

For the solution of most of the problems which are connected to the biological and physiological role of natural uranium in plants and animal organisms about 10⁻¹⁴ g uranium should be determined. However most of the physico-chemical methods for the determination of natural uranium in biomaterials are time-consuming and possess considerable error. On the basis of addition and inner standard methods a version of Solid State Nuclear Track Detectors (SSNTD) method has been developed in order to determine the natural uranium in biospecimens. According to the experimental data simple relations have been obtained for the calculation of uranium concentration in biomaterial and minium uranium concentration in biosolution which can be measured by the detector used. Under irradiation of SSNTD at a thermal neutron flux of (3–5)·10¹⁵n·cm⁻² the detector sensitivity is 2.30·10⁻⁹ g U/ml for glass detectors; 9.60·10⁻¹⁰g U/ml for the detectors made from artificial mica.     

Mapping of transuranic elements in soil by nuclear track methodology

This work presents an alternative method to map the distribution of transuranic elements, which is characterized by its simplicity in both implementation and instrumentation. The method is based on the interaction of alpha particles in polymeric materials and the formation of tracks, which become visible after chemical etching. Nuclear track detectors are placed on the soil in order to evaluate the distribution of the radioactive material and its relative intensity for transuranic contaminants. CR-39 polycarbonate was used as a nuclear track detector in this study. Chemical etching was done with a 6.25M KOH solution in a closed system for 16 hours. The readings were performed in an automatic system using digital image analysis. The results show the distribution of the contaminants and their location, identifying the zones with large intensities. This method is attractive for use in areas contaminated with alpha particles, and specially transuranic elements, because it involves in situ measurements, generates very low amounts of radioactive waste, and the detectors are easily handled.