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  • Author or Editor: K. Aardaneh x
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Summary  

A column chromatography was developed using a nonionic, polar adsorbent resin Amberlite XAD-7 for routine radiochemical separation of 67Ga from Zn and Cu. 7M HCl was found to be the optimum concentration for adsorption of 67Ga and elution of both Zn and Cu. Distilled water was used for elution of 67Ga from the column. The optimum flow rate of the solutions on to the column was 5 ml/min. The concentrations of Zn and Cu in the final product (30 ml), measured by a polarography method, were 2.0 and 0.5 ppm, respectively. A solvent extraction method, using diisopropyl ether/7M HCl system was also tested to perform the same separation and a comparison between the two methods was made. The radiochemical chromatographic separation system is simple in design and easy to operate for separations in a hot cell.

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Abstract  

A radiochemical separation method was developed for the separation of 109Cd from a nat.Ag target (6.6 g, pressed into a 19 mm disc). The method comprised of two stages. In the first stage, after dissolution of the target in nitric acid, silver was separated from Cd by precipitation into the metallic form using 20 g of Cu turnings for the reduction of Ag+ ions. In the second stage, 109Cd in the filtrate, that contained trace amount of silver and substantial quantity of Cu(I), was purified by use of a Bio-Rad AG1-X10 anion-exchange resin. The ion-exchange chromatography employed a column with (1.6 cm i.d. and 4 cm length) with a flow rate of 2 ml/min throughout the separation. 109Cd was quantitatively recovered from the first stage and the recovery yield from the ion-exchange chromatography was greater than 96%. 2M HCl containing H2O2 was used for the adsorption of 109Cd and elution of Cu. 109Cd was eluted by 50 ml 1M HNO3. The concentrations of stable isotopes of Ag and Cu in the final solution (5 ml 0.05M HCl) were measured by an ICP-OES method and found to be <1 ppm.

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Abstract  

Two radiochemical separation methods were developed for the separation of 88Y from a SrS target (3.2 g, pressed into a 19 mm disc) and Al (2.5 g, the capsule contained the target). The first method was based on solvent extraction technique using undiluted TBP/HNO3 system and the second was an extraction chromatography using a column packed with TBP-impregnated Amberlite XAD-4 resin. A simple procedure was used for the impregnation of the XAD-4 resin with TBP. For both methods concentrated nitric acid was used for extraction/adsorption and 2M HCl for back extraction/elution of 88Y. In terms of recovery of 88Y, the solvent (TBP)-impregnated resin showed better results (average 91.2% compared to 88.9% with extraction).

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Summary  

The target for the production of68Geconsists of a disc of gallium suboxide, Ga2O, with a 19 mm diameter. The suboxide was primarily prepared by repeatedly mixing metallic Ga and Ga2O3at 700 °C. The target (2.4 g) was quite stable under a long-time irradiation with a 34 MeV proton beam at a current of ~80mA. The dissolution of the target was performed using 12M sulphuric acid solution, assisted with the dropwise addition of 30% H2O2solution, and took less than 4 hours. A solvent extraction method, using a 9M H2SO4-0.3M HCl/CCl4system, was employed for the radiochemical separation of68Ge from Ga and Zn radionuclides, while 0.05M HCl was used for the back extraction of68Ge from the organic phase. The68Ge obtained in the dilute HCl was directly loaded onto a column containing either a hydrous tin dioxide or a crystalline tin dioxide, obtained by calcinations of the hydrous oxide at 450, 700, and 900 °C. The calcinated hydrous tin dioxide at 900 °C showed the highest crystallinity and highest68Ga elution yield and was selected for use in the generator. The68Ga elution from the column generator packed with 2 g of tin dioxide, using 3 ml of 1M HCl, and yielded an average of 65%. The breakthrough of68Ge was 6.1. 10-4%.

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Summary  

Ion-exchange chromatography using the chelating resins Purolite S950 and Chelex 100 was investigated for the radiochemical separation of 82Sr from a RbCl target. 0.25M NH4Cl solution was employed for the retention of Sr and elution of Rb, and 2M HCl for the elution of Sr. Although both resins showed very similar results, the conditions for adsorption of Sr were different. The ammonium chloride solution was directly used with Purolite S950 while it was necessary to adjust the pH between 9 and 10 with Chelex 100. Purolite S950 was, therefore, selected for routine production of 82Sr. A procedure has been introduced for the preparation of a hydrous tin dioxide as supporting material for the 82Sr/82Rb generator column. All components of the generator column were made up of stainless steel. The column was 4 cm long, 9.5 mm O.D. and 7.1 mm I.D. Using isotonic saline (0.9% NaCl) for elution of 82Rb, elution curves with different flow rates ranging from 5 to 20 ml/min were obtained. Maximum available 82Rb was eluted in the first 20 ml. The column generator provided a sterile 82Rb in isotonic saline. The breakthrough of 82Sr over 4 weeks of elution using 7 liter of saline was on average 4.5 . 10-5% (based on the first 20 ml eluate).

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Summary  

Rhodium electrodeposition on a copper substrate was investigated for 103Pd production. The electrodeposition was carried out by the commercially available Rhodex plating baths. The optimum conditions of the electrodeposition for complete depletion of Rh were: 6.2 g/l rhodium, DC current density of 12.83 mA . cm-2 and 60 °C temperature.

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Yttrium-88 was produced from irradiation of a SrCl2 target (4.8 g, pressed into a 19 mm disc) by 33 MeV proton beam at a current of up to 90 mA. Chelating resin Chelex 100 (H+ form, 100-200 mesh) was used for the separation of yttrium radionuclides (including 88Y) from strontium. 0.01M nitric acid was used for the dissolution of target (100 ml), retention of Y and elution of Sr (200 ml). For the elution of yttrium, 25 ml 1M HNO3 was employed. The column was 4 cm long with internal diameter of 1.6 cm. The flow rate was 1 ml/min throughout the separation procedure. The 88Y recovery yield was 94% average and the stable Sr content in the final product (5 ml 0.1M HCl) was estimated to be less than 3 ppm.

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Abstract  

A radiochemical process is reported for the production of 103Pd from Ag targets for use in brachytherapy. The procedure, which is based on anion exchange chromatography, separates Pd from a large amount of target material (16 g Ag), as well as Rh radioisotopes (mainly 101Rh and 100Rh), which are produced from decays of their Pd parents. The AG MP-1 anion exchange resin was used for the process. For elution of Rh and Ag, 3M nitric acid solution was used and 5% ammonia solution was used to elute the Pd. The average recovery of Pd was 97.4%. An elution curve for Pd was set up and a panel for the radiochemistry designed and installed in a hot cell.

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Abstract  

Experimentally measured cross-sections are presented for the first time for the 192Os(p,α3n)186Re nuclear reaction up to 67 MeV. Highly enriched thin 192Os targets (15 pcs), prepared by electro-deposition onto Cu backings, were irradiated with an external proton beam delivered by the SSC cyclotron of iThemba LABS. The excitation function curve of the 192Os(p,α3n)186Re reaction shows a maximum cross-section of ~82 mb at about 24 MeV. According to the yield calculations based on the present results, the available cumulative no-carrier-added 186Re yield is 7.76 MBq/μAh (0.21 mCi/μAh) over the energy region 13.4 → 27.3 MeV.

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Abstract  

Production cross sections of residues with mass near to that of the target were measured in 12C and 16O induced reactions on Rh at an incident energy of 400 MeV. An ion-exchange method has been developed for the separation of Rh, Pd and Ag nuclides from all other produced activities. Rh and Ag nuclides were separated from elements such as Pd, Ru, and Tc, amongst others, on an AG1-X8 anion exchange resin in 6M HCl. The Ag nuclides were then removed from the effluent using a precipitation technique so that only Rh remained in the final solution. The Pd was afterwards separated from Ru and Tc by eluting it from the resin with 5% ammonia solution. This procedure made it possible to accurately measure production cross sections for 103mRh and 103Pd. Cross sections for the production of various other observed residues are also presented. The results are consistent with an enhanced isobaric yield in the near-target mass region. The radiochemical separation technique is also suitable for the routine production of Pd and Rh nuclides, e.g., 103Pd and 101mRh, in proton-induced reactions on Rh targets

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