Ascorbic acid as an eluent for99mTc in99Mo−99mTc generator system

A simple chromatographic procedure for clean separation of the important radionuclide,^99m Tc, in the equilibrium mixture,⁹⁹Mo−^99mTc, has been demonstrated. Separation of pure^99mTc has been achieved by preferential extraction of the radioisotope through an anion exchange resin column of Amberlite IRA-410 using Na-ascorbate solution at pH 7 as an eluent. The radiochemical purity of the separated radiotracer has been verified by taking recourse to γ-ray spectrometry. The potentiality of the developed procedure lies in the facts that the eluting agent, ascorbic acid, itself h got its own biomedical importance as Vitamin C and the concerned radioisotope can be obtained in both Tc(IV) and Tc(VII) states as per requirement for diagnostic purposes.     

Determination of rare earth elements by radioisotope induced X-ray emission spectroscopy

A ring-shaped, 10⁹ Bq²⁴¹Am radioisotope source was used for the excitation of K-shell X-rays from rare earth elements (56<Z<64), present in powdered geological material. In order to improve the efficiency of the measurement of these elements in the concentration range down to 10 ppm, the optimum geometry of the system was found. The results obtained are presented and discussed.     

Elemental analysis of selected Indian monazite ores by energy dispersive X-ray fluorescence /EDXRF/ spectroscopy

Analysis by Energy Dispersive X-ray Fluorescence spectroscopy of monazite ores from Kerala /Chavara and Manavalakurichi/, Orissa /Chattrapur/ and Tamil Nadu /Tirunelveli/ has been carried out for the determination of their elemental composition using¹⁰⁹Cd /annular/ and²⁴¹Am /disc/ radioisotope sources. The elements Y, Zr, Mo, Pb, Th and U were analyzed using a¹⁰⁹Cd source, and the elements La, Ce, Pr, Nd, Sm, Gd and Dy were analyzed using the²⁴¹Am source in side source geometry. Quntitative results on these 13 elements present in these ores were obtained by the EDXRF technique. It was seen that despite the diverse geological settings, there is remarkable similarity in the elemental composition of these ores, although some trace elements do show certain variations from sample to sample. These results are presented and discussed in this paper.     

Exposure dose assessment and discussion on radioisotope production and application

The exposure dose status on radioisotope production and application in China has been assessed in the paper. The average annual occupational exposure dose received by workers in the radioisotope production is about one tenth of the annual dose limit in normal situation. It is less than one twentieth for workers in the radioisotope applications. However, the annual collective dose for the latter is higher than the former by one oder of magnitude due to the larger number of workers in the application field. Although the output of radioisotopes increased doubly in 1980's as compared with 1970's, the increase on the annual collective dose was not obvious. For exposure to the public,¹³¹I for example, the collective dose in the radioisotope production decreased by one to two orders of magnitude and the releasing factor reduced by two orders of magnitude. Therefore, the exposure dose received by workers in radioisotope production and application is lower in normal situation. However, the facts worth paying attention to are that there were many events and accidents which happened in the radioisotope applications, especially at the irradiation facilities. The probability of fatal accident was as high as 10^–3 per irradiator year. In order to improve the radiation safety situation, it is imperative to conduct the safety assessment for irradiation facilities, to enhance management of the radioactive wastes and spent sources and to establish the experience feedback system.     

Xenon isotopic signature study of the primary coolant of CANDU nuclear power plant to enhance CTBT verification

To support interpretation of observed atmospheric ¹³⁵Xe, ¹³³Xe, ^133mXe and ^131mXe, a database of xenon radioisotope in the primary coolant of CANDU reactors has been established. This database is comprised of 40000 records of high-quality xenon radioisotope analyses. Records from the database were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to study isotopic ratios of observed xenon radioisotopes in the CANDU reactor primary coolant. These studies provided novel and practical information on the characterization of CANDU reactor xenon radioisotope releases, which can be used to discriminate between reactor effluence and underground nuclear test releases.     

Elemental analysis of Cu−Ni and Nd−Al alloys and, nickel and iron powders by energy dispersive X-ray fluorescence (EDXRF) technique

Energy dispersive X-ray fluorescence spectroscopy (EDXRF) has been used for elemental analysis of Cu−Ni alloy, neodymium aluminide, and iron and nickel powder. The preparation of Cu−Ni alloy and neodymium aluminide has been carried out by aluminothermic reduction of mixed oxides of copper and nickel and neodymium oxide respectively. Aqueous electrorefining technique has been followed for the preparation of iron and nickel powder using Fe−Ni alloy as anode. The determination of major and trace elements present in the Cu−Ni and, electrolytically refined nickel and iron has been accomplished by EDXRF using Cd¹⁰⁹ radioisotope source. In the case of Nd−Al alloy Am²⁴¹ radioisotope source has been used. The rapid and multielement analysis of the thermit product by EDXRF has aided in the appropriate variation of the charge constituents during the standardization of the optimum charge composition for Cu−Ni alloy. EDXRF analysis of electrolytically refined nickel and iron revealed heavy contamination of iron in nickel as compared to that of nickel in iron. Neodymium content has been found to be 67.68% in Nd−Al alloy.     

Thermal modeling of high-current solid targets

Production demands at TRIUMF have pushed present target designs to the limit of their beam current capacity. A thermal analysis of the present high-current solid production targets has been carried out in order to increase radioisotope production rates through maximizing current handling capability. This paper describes the optimization of a 5° incident angle solid target for radioisotope production in service on the TRIUMF TR-30 cyclotron. Target materials compared include silver and Glidcop^®,¹ a dispersion-strengthened copper composite. A summary of comparative results is presented.     

Krypton isotopic signature study of the primary coolant of CANDU nuclear power plant

To support interpretation of observed atmospheric krypton radioisotopes, a database of krypton radioisotope in the primary coolant of CANDU reactors has been established. This database is comprised of 40,000 records of high-quality ⁸⁹Kr, ⁸⁷Kr, ⁸⁸Kr and ^85mKr analyses. Records from the database were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to study isotopic ratios of observed krypton radioisotopes in the CANDU reactor primary coolant. These studies provided practical information on the characterization of CANDU reactor krypton radioisotope, which can potentially be used to discriminate between reactor effluent and fuel reprocessing for nuclear safeguard ⁸⁵Kr monitoring applications (Kalinowski et al., J Environ Radioact 73:203, 2004). The study also has some potential application to Fissile material cut-off treaty.     

Precision measurement of Fe concentration in dolomites using radioisotope X-ray fluorescence

A series of dolomite bore hole samples have been analyzed for their iron content using radioisotope X-ray fluorescence. A precision of ±0.1%, as specified for oil and gas exploration, has been met using a non-destructive sample preparation technique, energy dispersive detector,¹⁰⁹Cd source and a micro-computer based data acquisition and reduction system. Sample and standard preparation procedures are discussed.     

New technique for the determination of trace elements using multiparameter coincidence spectrometry

Multiparameter coincidence g-ray spectrometry based on g-g coincidence is widely used in the field of nuclear structure studies, and has produced many succesful results. In this paper, feasibility of the method for neutron activation analysis of trace elements was studied. Particularly, a long-lived radioisotope ¹²⁹I (T_1/2 = 1.57^.10⁷ y) in algae samples and iridium in geological samples has been determined.     

Effect of nitrate on the determination of iron concentration in phytoplankton culture medium by liquid scintillation counting (LSC) method using 55Fe as radioisotope tracer

Liquid scintillation counting (LSC) method using a radioisotope tracer has several advantages such as simple procedure, high sensitivity and low detection limit, and has been used for the determination Fe concentrations in water samples. Several factors such as nitrate concentration, pH, chelating ligand affect the efficiency of this method in the determination of iron (Fe) in waters. In this study, the effect of nitrate in phytoplankton culture medium on the determination of Fe concentration by LSC method using ⁵⁵Fe radioisotope tracer was evaluated. The measured Fe concentrations in the medium were lower than its added concentration (1.5 μM) when liquid samples contain nitrate. Fe concentrations decreased exponentially as nitrate concentrations increased up to 2.64 mM, reaching a constant value of 1.31 μM Fe at nitrate concentrations higher than 2.64 mM. A correction factor (f = 1.14) was calculated from the decrease rate of Fe concentrations at different nitrate concentrations in the phytoplankton culture medium. This correction factor can be used to correct the measurement values of Fe concentrations in phytoplankton culture medium obtained from LSC method. Our results showed that up to 94 % of the added Fe can be determined by LSC using ⁵⁵Fe radioisotope tracer. The remaining 6 % was probably bound to the walls of the culturing vessel. This method is also applicable for the measurement of Fe size-fractionation in phytoplankton culture medium.     

Identification of 5-(3,4-Dihydroxyphenyl)-5-Phenylhydantoin: A Metabolite of 5,5-Diphenylhydantdin (Dilantin1) in Rat Urine

Abstract

Using radioisotope tracer technics and GC-mass spectrometry, a new metabolite of 5,5^?diphenylhydantoin present in rat urine has been dentified as 5-(3,k-dihydroxyphenyI)-5-phenylhydantoin. This catechol represented about 2% of the total metabolites excreted in rat urine folowing administration of diphenylhydantoin in the diet for over two weeks     

Production of the radioisotope88Y

Carrier-free⁸⁸Y radioisotope, which has the longest half life /T=106.6 d/ of yttrium radioisotopes and is a -ray emitter, was obtained by proton irradiation of strontium, followed by cooling for one month. Then,⁸⁸Y was purified by precipitating strontium as strontium nitrate and extracting yttrium with tri-n-butyl phosphate /TBP/. The decontamination factor of strontium to yttrium was more than 4×10³ and chemically pure yttrium radioisotope was obtained.     

Linhchi mushrooms as biological monitors for137Cs pollution

Radioactivity of Linhchi mushrooms (Ganoderma Lucidum) cultivated in laboratory and production conditions has been measured in the Environmental Laboratory of Nuclear Research Institute (NRI), Dalat, Vietnam. The results showed that Linhchi mushroom has a high radioactive concentration of¹³⁷Cs, which is about 20 Bq kg^–1 fresh weight. In addition, the radioactive contents of substrata before and after cultivation were insignificant. This suggested that Linhchi mushroom should only accumulate the¹³⁷Cs radioisotope from the atmosphere, directly. Therefore, it should be considered as a bio-indicator for environmental monitoring.     

Untersuchung der Na+-Verteilung in Kieselglas Mittels der Radiotracertechnik

The mobility of Na⁺ ions has been investigated by²⁴Na radioisotope in silica glass between 800 and 1400 °C. The evaluation was made by autoradiography. It was established that the distribution of sodium ions in the SiO₂ matrix depends on the homogeneity of the substance studied. In inhomogeneous materials Na⁺ migrates along inner surfaces such as grain boundaries, dislocations, etc., while in bubble-free homogeneous substances the diffusion observes the Fick law. For the latter case the diffusion coefficients have been calculated.     

Geant4 Monte Carlo radioxenon beta-gamma coincidence efficiency simulation for a phoswich detector

In this work, a Monte Carlo (MC) simulation model is established to accurately characterize a phoswich beta-gamma coincidence detector system. This model can be easily used to predict the beta-gamma coincidence efficiencies of xenon radioisotopes at various stable xenon concentrations in the counting cell. The results demonstrate that there is a significant inverse correlation between beta-gamma coincidence efficiency and stable xenon concentration. The influence of stable xenon concentration on beta-gamma coincidence counting efficiency has been investigated for each individual xenon radioisotope. The results indicate that the effect of stable xenon concentration on beta-gamma coincidence efficiency depends on the xenon radioisotope and its decay modes. The coincidence efficiency of ¹³³Xe with 31.0-keV X-ray decay mode is the most affected one; and then followed by ^131mXe, ¹³³Xe with 81.0-keV gamma-ray decay mode, ^133mXe and finally ¹³⁵Xe. The study also indicates that the gamma absorption by xenon gas plays more of a role in the decrease of beta-gamma coincidence efficiency for ¹³³Xe and ¹³⁵Xe, and that the conversion electron spectrum shifting and broadening plays more of a role in the reduction of beta-gamma coincidence efficiency for the metastable radioxenon of ^131mXe and ^133mXe.     

Recovery of plutonium from aqueous waste solutions using porous zirconia spherical particles

Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify the reactor coolant half-life of ¹³⁵Xe and ¹³³Xe, as well as the correlations of ¹³⁵Xe and ⁸⁸Kr activities.     

Mixed insoluble acidic salts of tetravalent metals IV. Crystalline mixed zirconium — Titanium phosphates

Mixed crystalline alpha zirconium — titanium phosphates with variable zirconium to titanium ratios have been prepared both by the well known gel reflux method and a modified HF method. Chemical analysis, X-ray, i.r. and thermal analysis were used to characterize the materials. Exchange capacities for these ion-exchangers have been evaluated by pH-titration combined with radioisotope tract technique for Na⁺, K⁺, Rb⁺ and Cs⁺.     

Individual extraction constants of some univalent cations in the two-phase water–phenyltrifluoromethyl sulfone system

The preparation and characterization of three different phases of zirconium phosphate (ZrP) have been carried out using XRD, SEM, EDX, and FTIR spectroscopy. The phases exchange and sorption properties with three different radioisotope ²³⁴Th, ²³⁸U, and ¹³⁴Cs were investigated.     

Determination of trace elements and radioactive materials by substoichiometric isotope dilution analysis

Substoichiometric isotope dilution analysis has been applied for the determination of trace elements in liquid samples, of carrier content in radioisotope solution and of concentration of organic reagent. Cu in mineral acids and in ZnSe single crystal was determined by the substoichiometric extraction with dithizone. The values of 1.8 and 0.018 ppm in nitric acid and distilled one and of 1.4 and 0.44 ppm in ZnSe were obtained. Cu and P carrier contents in⁶⁴Cu and³²P solutions were determined by the substoichiometric extractions with dithizone in CCl₄ and with molybdic acid into MIBK in the series of the solutions adding various amounts of Cu or P carrier. An analogous method has been applied for the determination of dithizone and diethyldithiocarbamate solutions. The method was also applied for the determination of⁶⁰Co radioactivity in environmental samples. The analytical result of water samples is described.