Volume 97, Issue 12

Proton rich Tc radionuclides have been produced for the first time through 89 Y( 9 Be, xn ) 93,94,95 Tc reactions. In order to optimize the yield of a particular radionuclide of choice, batch yield of 93 Tc, 94 Tc and 95 Tc have been measured at different incident energies using stacked-foil technique followed by off-line γ-spectrometry. No-carrier-added (nca) 93,94,95 Tc radionuclides have been separated from bulk yttrium by liquid–liquid extraction (LLX) and solid–liquid extraction (SLX) techniques. Trioctylamine (TOA) diluted in cyclohexane was used as liquid anion exchanger in LLX in presence of HCl. SLX was carried out using cation and anion exchanger resin, DOWEX-50 and DOWEX-1, respectively, in HCl medium.

The radionuclide 64 Cu ( T 1/2 =12.7 h) is an important non-standard positron emitter, suitable for combining PET imaging and targeted therapy. Its production in no-carrier-added form is done via charged particle induced reactions, and considerable amount of cross section data are available in the literature. We evaluated seven reactions, namely 64 Ni( p , n ) 64 Cu, 64 Ni( d , 2 n ) 64 Cu, 68 Zn( p , α n ) 64 Cu, 66 Zn( p , 2 n ) 64 Cu, 64 Zn( d , 2 p ) 64 Cu, 66 Zn( p , α) 64 Cu and nat Zn( d , x ) 64 Cu. Data analysis was generally limited up to about 25 MeV and the consistency check of experimental data was carried out using the nuclear model codes STAPRE, EMPIRE and TALYS. In a few cases experimental data were available up to 100 MeV; the consistency check in the high energy region was done only using the code TALYS. A statistical procedure (supported by nuclear model calculations) was then used to fit the data. The derived recommended sets of data, together with 95% confidence limits, are reported. The integral yields calculated from those data are also given. A critical comparison of the various production routes of 64 Cu is presented. The 64 Ni( p , n ) 64 Cu reaction, utilizing a highly enriched target, is the method of choice.

A new value of 126 Sn half-life was determined by combination of inductively coupled plasma-mass spectrometry (ICP-MS) and gamma spectrometry measurements on purified sample solutions collected from nuclear fuel reprocessing. 126 Sn was isolated through dissolution of fission product precipitates and liquid-liquid extraction with N -benzoyl- N -phenyl-hydroxylamine (BPHA). The abundance of 126 Sn atoms together with the absence of interfering species in the analysed solutions made it possible to measure both mass concentration and nuclide activity with high precision and accuracy. This led to a 126 Sn half-life value of 1.980(57)×10 5  a.

The vacancy transfer probabilities from K -shell to L 2 -, L 3 - and L -shell/subshells were measured in Fe x Zn 1- x thin film alloys. The samples were excited by γ photons with energy 59.5 keV from a 50 mCi 241 Am radioisotope source. The emitted K X-rays were detected by an Ultra-LEGe having a resolution of 150 eV at 5.9 keV. For comparison with experimental results, theoretical calculations have been made using radiative and nonradiative transition rates. The measured results are in good agreement with theoretically calculated values within experimental errors. Fe x Zn 1- x thin film alloys were electrochemically deposited on aluminum substrates from sulfate bath. In conclusion, it was found that the vacancy transfer probabilities changed in Fe x Zn 1- x thin films for different compositions of x .

We perform X-ray absorption spectroscopy (XAS) investigations to monitor the stabilization of redox sensitive trivalent and tetravalent actinide ions in solution at acidic conditions in a pH range from 0 to 3 after treatment with holding reductants, hydroxylamine hydrochloride (NH 2 OHHCl) and Rongalite (sodium hydroxymethanesulfinate, CH 3 NaO 3 S). X-ray absorption near edge structure (XANES) measurements clearly demonstrate the stability of the actinide species for several hours under the given experimental conditions. Hence, structural parameters can be accurately derived by extended X-ray absorption fine structure (EXAFS) investigations. The coordination structure of oxygen atoms belonging to water ligands surrounding the actinide ions does not change with increasing pH value (approximately 11 O atoms at 2.42 Å in the case of U(IV) at pH 1, 9 O atoms at 2.52 Å for Np(III) at pH 1.5, and 10 O atoms at 2.49 Å for Pu(III) up to pH 3), indicating that hydrolysis reactions are suppressed under the given chemical conditions.

In this study, densely crosslinked poly(methacrylic acid) was used to adsorb uranium(VI) ions from aqueous solution. For this purpose, the crosslinked copolymer of ethylene glycol dimethacrylate (EGDM) and methacrylic acid (MA) containing 25% (w/w) methacrylic acid (MA) was synthesized by using dibenzoyl peroxide- N , N -dimethylaniline (BPO-DMA) initiator system at room temperature. The adsorption of uranium(VI) ions on the copolymer sample (0.02 g copolymer/5 mL solution of U(VI) ions) was carried out in a batch reactor. The parameters which effect the uranium adsorption process, such as, contact time, pH of solution, initial uranium(VI) concentration and temperature were investigated. It was observed that an increase in these parameters enhanced the removal of U(VI) ions from aqueous solution. The adsorption data were modelled by the Freundlich, Langmuir and Dubinin–Radushkevich (D–R) isotherms. The adsorption capacity of the crosslinked copolymer and free energy change were calculated by using D–R isotherms. Thermodynamic parameters (Δ H °, Δ S ° and Δ G °) were determined for the adsorption of U(VI) ions from aqueous solutions by the crosslinked copolymer bearing methacrylic acid functional groups. Experimental adsorption data were analyzed using sorption kinetic models of the pseudo-first order and pseudo-second order kinetic models. It was observed that pseudo-second order kinetic model provided a high goodness of fit with experimental data for the adsorption of U(VI) ions on the crosslinked copolymer bearing methacrylic acid functional groups. The densely crosslinked poly(methacrylic acid) might be of interest in large scale uranium removals from aqueous solution, since it had high uranyl sorption capacities ranging from 0.16 mmol/g to 2.37 mmol/g copolymer at pH 2.7 (293 K).

Extraction of americium(III) from nitric acid medium by a solution of tri- n -butylphosphate (TBP) and n -octyl(phenyl)- N , N -diisobutylcarbamoylmethylphosphine oxide (CMPO) in room temperature ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (bmimNTf 2 ), was studied and the results were compared with that obtained with CMPO-TBP in n -doddecane ( n -DD). The distribution ratio of 241 Am(III) in TBP-CMPO/bmimNTf 2 was measured as a function of various parameters such as concentrations of nitric acid, CMPO, bmimNO 3 , NaNO 3 and TBP and temperature. Remarkably large distribution ratios were observed for the extraction of americium(III) when bmimNTf 2 acted as diluent and the extraction was insignificant in the absence of CMPO. The stoichiometry of metal–solvate in organic phase was determined by the slope analysis of extraction data and it indicated the formation of 1:3 (Am:CMPO) complex in organic phase. Viscosity of TBP-CMPO/bmimNTf 2 at various temperatures and enthalpy change accompanied by the extraction of americium(III) were determined and reported in this paper.

As a part of NEXT, the behavior of Np in a simplified solvent extraction process using TBP as an extractant for U, Pu and Np co-recovery was investigated. Two approaches to Np co-recovery with U and Pu in the irradiated fast reactor core fuel using a dissolver solution in a counter current were examined. One used a feed solution with a high HNO 3 concentration, and the other used a scrubbing solution with a high HNO 3 concentration. The leakages of Np to the raffinate were 1.1 and 4.7% using high HNO 3 concentration feed and scrubbing solutions, respectively. Simulation results based on these experiments showed that high HNO 3 concentration in the feed solution is advantageous for the Np extraction because Np oxidation progresses in the feed solution before being supplied into the centrifugal contactor, and there is less effect of HNO 2 at the extraction section.

109 Cd was produced at a cyclotron via nat Ag( p , n ) 109 Cd reaction by irradiation of an electroplated target with 15 MeV protons. The obtained yield was 70 kBq/μA h. The separation was performed using hematite nano-particles as sorbent which were synthesized by a solid-state chemical reaction method. The effect of different parameters, such as pH and the sorbent concentration, on extraction efficiency were investigated. The phase morphology, nanostructure and size of nano-particles were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The chemical and radionuclidic purity of 109 Cd was determined by ICP-AES and HPGe detector gamma-ray spectrometry, respectively.

There is an increasing interest for 90 Y for radionuclide therapy. However, radioimmunotherapy, one of the most important applications for 90 Y, demands a very high purity product. Obtaining a high quality 90 Y is difficult not only because of the complex and time consuming production schemes but also because of the quality control which has challenging tasks like the determination of 90 Sr at very low concentrations. The present paper investigates a reported purification procedure for the removal of stable metal trace contaminants from an 90 Y solution, seeking for its potential use in the elimination of the radioactive contaminant 90 Sr and its fast determination. For this purpose a washing step with HNO 3 acid is introduced to elute 90 Sr, the order of each acid solution is rearranged to reduce the potential contaminants present in acids and the size of the column is reduced to further optimize the procedure. As a result, an improved purification method is obtained, which allows the removal of both trace metal contaminants and 90 Sr from an 90 Y solution and the measurement of 90 Sr/ 90 Y ratios of the order of 10 -7 , which are well below the established pharmacopeia limit of 2×10 -5 .

We describe a preparation of novel polymer vectors of 64 Cu based on co-polymers of poly- ( N -isopropylacrylamide) and poly- ( N -hydroxypropylmethacrylamide). DOTA, DTPA, dipicolylamine, thiosemicarbazone and Ag-ionophore-II ligands were tested to bind 64 Cu in a polymer chain. Labeling yields with no-carrier-added 64 Cu varied from 95 to 99% in 30 min. at laboratory temperature. Vectors were stable in vitro for 24 h in human serum and might be prospective for targeted 64 Cu radio or combined radiochemotherapy.

Since, to date very limited information on the distribution and function of the adenosine A 3 receptor is available, the development of suitable radioligands is needed. Recently, we introduced [ 18 F]FE@SUPPY (5-(2-[ 18 F]fluoroethyl) 2,4-diethyl-3-(ethylsulfanylcarbonyl)-6-phenylpyridine-5-carboxylate) as the first PET-ligand for the A3R. Regarding the metabolic profile – this class of dialkylpyridines comprises two ester functions within one molecule, one carboxylic and one thiocarboxylic – one could expect carboxylesterases significantly contributing to cleavage and degradation. Therefore, our aim was the development of [ 18 F]FE@SUPPY:2 (5-ethyl 2,4-diethyl-3-((2-[ 18 F]fluoroethyl)sulfanylcarbonyl)-6-phenylpyridine-5-carboxylate), the functional isomer containing the label at the thiocarboxylic moiety. For satisfactory yields in high scale radiosyntheses, a reaction temperature of 75 °C has to be applied for at least 20 min using 20 mg/mL of precursor. So far, 6 complete high-scale radiosyntheses were performed. Starting from an average of 51.2±21.8 GBq (mean±SD) [ 18 F]fluoride, 5.8±4.1 GBq of formulated [ 18 F]FE@SUPPY:2 (12.0±5.4%, based on [ 18 F]fluoride, not corrected for decay) were prepared in 75±8 min.

Effects of different diluents on the extraction of cobalt(II) and indium(III) oxinate complexes have been studied using Co-60 and In-114m as radiotracers. Theory of regular solutions was applied for the determination of solubility parameters (δ) of cobalt oxinate and indium oxinate which were found to be 34.45 J 1/2 cm -3/2 and 34.03 J 1/2 cm -3/2 , respectively. Besides, distribution of each of the two complexes was studied in the mixtures of two solvents, assigned as good and poor solvents, in accordance with their individual behaviors. In both of the two cases, experimentally determined values of distribution-coefficient differed from those of calculated values which shows the importance of solute-solvent and solvent-solvent interaction in the present system.

Nine samples of chewing tobacco, snuff, tobacco leaf and ash were analyzed using Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectroscopy (AAS). Almost all samples of chewing tobacco and snuff studied in this work contain substantial amounts of Mg, Mn, Na, K, V, Sc, Rb and Fe. Furthermore, varying amounts of Al, Ba, Ca, Ce, Co and Zn were also detected in all tobacco samples. Of the toxic elements which were determined using INAA, As, Sb and Hg were quantified in only few tobacco samples. However, other toxic elements, which were determined using AAS, such as Cu, Pb and Cd were detected in almost all samples of chewing tobacco and snuff. The concentration of majority of the detected elements is high in ash samples which imply that most elements in chewing tobacco and snuff may originate from the addition of ash.