N.G. Zaitseva

High-purity radionuclide production: material, construction, target chemistry for 26Al, 97Ru, 178W, 235Np, 236,237Pu

Abstract The work on isotopically pure 26 Al, 97 Ru, 178 W/ 178 Ta, 235 Np, 236 Pu and 237 Pu production was initiated because of intensive research on their applications in the biomedical field and environmental chemistry. The conditions for isotopically pure production have been investigated. This paper describes the data for the nuclear reactions of the radionuclide production, the different target designs and target chemistry procedures.

A new 92Ru neutron-deficient isotope

Both the growth and the decay of gamma-lines of the daughter 92Tc isotope and the direct decay of 92Ru have been observed. The half-life of the new 92Ru isotope has been determined to be T12 = (3·16 ± 0·33) min. the energies and the relative intensities of the 92Ru gamma-rays are: (134·68 ± 0·09) keV (57 ± 8); (213·94 ± 0·11) keV (84 ± 13); (259·41 ± 0·09) keV (100).

Radiation annealing behaviour of the radio-iodine recoils formed by high-energy proton irradiation of cesium chloride

Abstract The radio-iodine atoms formed by the high-energy proton irradiation of cesium chloride crystals appear in valency forms which are affected by the induced lattice-defects. The assumption is discussed that V-type centres act as strong oxidants for the recoil atoms. A protection effect of carriers and crushing the crystals, were found to be important in determining the chemical fate of the radio-iodine. The yield of radio-iodine atoms in higher oxidation states plotted against the total proton flux may be expressed by an equation which shows the proportionality between the number of displaced atoms in the lattice and the total flux of irradiation.

Chemical states of radioactive lanthanide atoms in Pr and Nd fluorinated β-diketonates

Abstract An investigation has been carried out of the chemical behaviour of radioactive lanthanide atoms formed in Pr and Nd trifluoroacetylacetonates and in Pr and Nd hexafluoroacetylacetonates irradiated with 660 MeV protons, and of those resulting from the implantation of the Ln ∗(1+) ions with an energy of 40 keV into crystalline Nd(HFA) 3 . The experimental conditions, in particular, the chemical composition of the medium and the state of the crystalline lattice, appear to be important factors affecting the chemical reactions of the Ln ∗ atoms and the forms in which they are stabilized. The behaviour of the Ln ∗ atoms introduced into crystalline Nd(HFA) 3 in different ways (by proton irradiation or ion implantation) indicates that it is independent of their energy.

Fast gas-thermochromatographic separation of ruthenium neutron-deficient isotopes from silver chloride

Abstract Separation of ultra microamounts of ruthenium from an irradiated silver chloride melt into the gas-phase at various temperatures and gas compositions (O 2 +Cl 2 ), and their distribution in the thermochromatographic column, which depends on these parameters, has been studied. The formation probability of volatile ruthenium compounds of various composition is discussed. Conditions for the fast gas-thermochromatographic separation of ruthenium isotopes from silver chloride, irradiated with 660 MeV protons, are determined.

The chemical behaviour of the Zr and Y recoil atoms in Zr and Y acetylacetonates irradiated with 660 MeV protons

Abstract The chemical states of zirconium and yttrium recoil atoms formed by irradiation of Zr and Y acetylacetonates with 660 MeV protons have been identified by chromatography and sublimation. The yield of recoil atoms in different chemical forms is shown to depend on both experimental conditions of the irradiation and the method of analysis, which suggests that the fate of the recoil species is substantially determined by its thermal reactions.

Thermal annealing of crystalline rhenium compounds irradiated with 660 MeV protons

Abstract The thermal annealing of crystalline sodium and ammonium perrhenates and potassium hexachlororhenate IV irradiated with 660 MeV protons has been studied. The isothermal curves obtained for sodium and ammonium perrhenates show the existence of competing reduction and oxidation reactions in the annealing process. Classical isothermal annealing curves have been obtained for potassium hexachlorohenate IV. The thermal annealing process involves the reduction of radiorhenium to the parent form. It is shown that the annealing behaviour of radiorhenium obtained by high energy proton or neutron irradiation is practically the same.

The behaviour of radio-iodine recoils formed by neutron and proton irradiation of some solid cesium compounds

Abstract The chemical states of radio-iodine formed by 14·6 MeV neutron and 660 MeV proton irradiation of different crystalline caesium compounds were determined. The radio-iodine distribution in oxidised and reduced forms depends both on the radio-iodine defect concentration and lattice composition. By thermal annealing large changes in the yield of oxy-forms were noticed.

Lanthanides in Nuclear Medicine: Preparation of 149Tb by Irradiation with Heavy Ions

Among radioactive isotopes of rare-earth elements (REEs) finding increasing application in nuclear medicine, α-emitting 149Tb (T1/2 = 4.118 h; EC 76.2%; β+ 7.1%; α 16.7%) shows promise for radioimmumotherapy. Formation of 149Tb in nuclear reactions Nd(12C, xn)149Dy(4.23 min; β+, EC) → 149Tb performed by irradiation of a Nd target with carbon ions was experimentally studied. As estimated from the experimental data on 149Dy formation and its decay into 149Tb, the 149Tb yield under the best conditions (142Nd-enriched target, 12C ions with the energy of up to 120 MeV and current of up to 100 μA, irradiation time 8-10 h) can be as high as 30 GBq (0.8 Ci).

Radioisotopes in Life Sciences. The Production of High-Pure Radionuclide Sources at FLNR, JINR

A short review of the current data concerning nuclear reactions, target chemistry and following applications of some radioisotopes as tracers is given in this report.