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We have determined the isomeric ratios of isomeric pairs 97m,gNb, 95m,gNb and 91m,gMo produced in 98Mo(γ, p)97m,gNb, 96Mo(γ, p)95m,gNb and 92Mo(γ, n)91m,gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for 97m,gNb from 14 to 19 MeV, for 195m,gNb from14 to 24 MeV except 20 and 23.5 MeV and for 91m,gMo at 14 and 15 MeV are the first time measurements.

The radionuclides (88)Zr and (89)Zr have been produced by cyclotron irradiation of (nat)SrO with 35 MeV α-particles at a beam current of 15 μA. The thick source production yield of (89)Zr is ~3.1 MBq μA(-1) h(-1). A two-step radiochemical purification utilising anion-exchange chromatography in hydrochloric and hydrofluoric acids has been developed to separate (88,89)Zr from the target material, natural strontium, the target substrate, aluminium, and long-lived (88)Y.

We have determined the isomeric ratios in 113In(γ, n)112m,g In and 113In(γ, 2n)111m,g In photonuclear reactions of natural indium induced by bremsstrahlungs with end-point energies in the giant dipole resonance (GDR) region. The investigated samples were irradiated at the electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna. The gamma spectra of the samples irradiated were measured with a spectroscopic system consisting of an 8192-channel analyzer and a high-energy resolution (180 keV at gamma ray 1332 keV of 60Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors. For both the mentioned reactions, the isomeric ratios in the bremsstrahlung energy range from 19 to 24 MeV in this work are new measurements.

A method to produce (117m)Sn radionuclide using accelerator production route is described. A new method is proposed to separate the (117m)Sn. Specific activities and thick target yield for (116)Cd(α,3n)(117m)Sn reaction at E(α)=35MeV bombarding energy were determined. The estimated production yield of (117m)Sn was 37.5kBq/μAh for 13.16 mg/cm(2) natural cadmium-oxide target and 410 kBq/μAh for 11.07 mg/cm(2) highly enriched (95%) (116)CdO target. The method developed for separation of (117m)Sn from Cd using anion-exchange resin (Dowex -1×8, fluorine form, 400 mesh) can achieve 98% radiochemical yield of (117m)Sn with more than 99% radionuclidic purity. The estimated specific activity is 2.4 GBq/mg that can be reached with the used irradiation conditions.

We have determined the isomeric ratios in 120Te(γ, n)119m,gTe, 122Te(γ, n)121m,gTe, 128Te(γ, n)127m,gTe and 130Te(γ, n)129m,gTe photonuclear reactions of natural tellurium induced by bremsstrahlungs with end-point energies in the giant dipole resonance (GDR) region. The investigated samples were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The gamma spectra of the samples irradiated were measured with spectroscopic system consisting of 8192 channel analyzer and high-energy resolution (180 keV at gamma ray 1,332 keV of 60Co) HP(Ge) semiconductor detector Canberra. The GENIE2000 (Canberra) computer program was used for data processing. The results were discussed and compared with those of other authors.

The concentration of natural radionuclides and the feasibility of recovery of uranium from browncoal ash of a Mongolian cogeneration plant were investigated. The concentrations of the elements were determined by instrumental gamma-activation (IGAA) and X-ray fluorescence (XRF) analysis. Uranium from brown-coal ash was leached with an 8 M HNO3 + HF (10%) mixture. The extraction of uranium from the solution and its purification for the removal of accompanying elements were carried out on an anion exchanger. An ash sample after leaching contains neither natural radioactive elements (238U and 232Th) nor their decay products, thereby allowing for the use of the ash as a building material.

The photonuclear reactions of (γ, xn) or (γ, xnp) types can be used to produce high-intensity neutron sources for research and applied purposes. In this work a Monte-Carlo calculation has been used to evaluate the production yields of neutrons from the (γ, n) and (γ, 2n) reactions following the bremsstrahlung produced by 100 and 200 MeV electron beams on the tungsten target. Our calculations indicated that the neutron yield is an increasing function of the target thickness in a considered range from 1.5 to 2.5 mm.

Molybdenum-99 was prepared by 100Mo(γ,n) photonuclear reaction on an electron accelerator, MT-25 microtron (FLNR). Natural Mo foil (9.6% 100Mo) and 100MoO3 (100% 100Mo) were used as the targets. The radiation yield of 99Mo was 3.2 kBq/(μA h mg 100Mo). Technetium-99m was isolated from the target material and concomitant radioactive impurities by an ion-exchange procedure. The possibility of preparing 99mTc generator from molybdenum carbonyl was studied. The content of radioactive impurities in the final 99mTc preparations was no higher than 10−5 Bq Bq−1.

The electrophoresis of zirconium and hafnium ions in aqueous solutions was investigated. No-carrier-added 88Zr and 175Hf have been used in microconcentrations (10-11M). The complexation of zirconium and hafnium with DTPA has been investigated in a large pH interval. The stability constants of the Zr-DTPA and Hf-DTPA complexes were determined for the first time by the method of horizontal zone electrophoresis in free electrolyte. The electrophoretic behavior of Zr(IV) and Hf(IV) ions in nitric acid solutions has also been studied.

In the framework of the Project DRIBs (Dubna Radioactive Ion Beams) the photofission reaction 238U(γ, f) has been studied at the FLNR (JINR) in view of producing beams of neutron-rich radioactive nuclei 132Sn and 142Xe using the MT-25 microtron [1].

Experimental results on the production and separation of 149Tb from natural neodymium target using the nuclear process Nd(12C,xn)149Dy→149Tb are presented. Terbium-149 was produced at the U-200 cyclotron of FLNR JINR by irradiating natNd2O3 with 12C ions and its possible production for nuclear medicine utilising the heavy-ion induced reactions was investigated.

The magnetic moment (g factor) of a negative muon on the 1s atomic levels of zinc and cadmium was measured with an accuracy higher by a factor of 7 than the accuracy achieved in other measurements. The experimental value of the g factor differs substantially from the theoretical results. Possible causes of this discrepancy are discussed.

We have determined the isomeric ratios of isomeric pairs 194m,gIr and 197m,gPt produced in 195Pt(γ, p)194Ir and 198Pt(γ, n)197Pt photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy and difference in the isomeric and ground state spins. The isomeric ratios of 194m,gIr and 197m,gPt from the present work, namely from 19 to 23 MeV for 194m,gIr and from 18 to 24 MeV for 197m,gPt are the first time measurements.

237U was produced by the reaction 238U(γ, n) on an electron accelerator, MT-25 microtron, at the Flerov Laboratory of Nuclear Reactions. For the separation of 237U and [238U, the recoil nuclei were collected by a nanostructured material, hydrated manganese dioxide (of the cryptomelane type), in the solid-solid system. From fission products, 237U was separated by ion exchange. The specific activity of the resulting 237U was 4.5 × 109 Bq (mg 238U)-1, with the content of radioactive impurities of ≤10-6 Bq Bq-1. The chemical yield of 237U was 80%.

A highly sensitive (detection limit 3 ×10-7 g g-1) procedure was developed for determination of Th in samples of soils and environmental objects. The method is based on the reaction 232Th(γ,n)231Th (T1/2 = 25.5 h). The samples were γ-irradiated for 4 h at an average electron current of 15 μA and electron energy Ee = 24.5 MeV. The Th content was estimated by recording X-ray emission of 231Th with Eγ = 25.65 keV. The X-ray spectra of the irradiated samples were recorded on an X-ray spectrometer with an Si(Li) semiconductor detector [30 mm2 area; resolution at the FeKα line (6.4 keV) 200 eV].

Distribution of uranium (VI) between soil solids and solutions is a key parameter in assessing the risk to the biosphere of disposing uranium-rich waste products from nuclear plants as well as uranium (U) ore mining. Both of these topics have recently been brought to public attention in Mongolia. Regional background levels of soil elements are an important dataset for accessing the actual environmental situation and monitoring pollution levels. Little information, however, is available on background concentrations of various elements in Mongolian soils. Thirteen rural soils were sampled from six provinces in Mongolia, and the concentrations of macro-, micro- and trace elements were measured. The values obtained served as a reference (baseline) for uncontaminated soils. The soils were characterized with slightly acidic to strongly alkaline pH values. With the exception of the sample from a western province, all the soils investigated contained little organic matter. The content of soil elements did not vary widely among geographical regions. The concentration of most micro elements was within the range of worldwide soil values but the value for Zn tended to be moderately higher. The U (VI) sorption into the soils was investigated using the batch technique and the 237 U radionuclide tracer, produced by the photo fission reaction 238 U( γ , n ) 237 U at an electron accelerator. The 237 U distribution coefficient ( K d ), derived from the sorption isotherms, was related to solution pH and varying from 9 to 2547 mL g -1 when the pH ranged between 3 and 7.7. The sorption process was interpreted in terms of the formation of different U (VI) species at given concentrations, calculated using the Speciation program with and without carbonate in the system. The U sorption isotherm displayed two general patterns: one where sorption decreased as solution pH increased, showing a maximum at pH 3, and another pattern revealed an adsorption maximum at pH 5 and then decreased up to pH 7.7 (the final solution pH). The observed decrease in K d when solution pH increased from 6 to 8 was consistent with the increased formation of soluble UO 2 (OH) 2 species. A linear negative correlation between lg K d and the solution pH was observed similarly to that reported for the soils with a pH ≥ 6.

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).

A good separation of the pair Md-Fm was performed on a spheroidal cation exchanger OSTION by means of ammonium α-hydroxy-α-methylbutyrate. The sepation factors and the position of elution peaks for elements of pairs Md-Fm and Ho-Dy are similar.

The subjects of investigation are depositions in the low stream of Arda river, East Rhodopes region, Bulgaria. The samples have been collected from soils at a depth of 0–20 cm. The samples have been analyzed for content of heavy metals (Pb, Zn, Cu, Ni, Cr).

The paper presents the results of the test for heavy metals (Pb, Zn, Cu, Ni, Cr, Ti, Mn, Fe) in soils collected from the stream of the Arda river up to the Greek border in the East Rhodopes region of Bulgaria. The results were obtained using X‐ray fluorescence analysis at the Flerov Laboratory for Nuclear Reactions, Joint institute for Nuclear Research, Dubna, Russia.

A new highly sensitive track method for the determination of thorium (232Th) and neptunium (237Np) has been developed. The technique includes the radiochemical separation procedure of the isotopes followed by the irradiation of the resultant samples on the MT-25 microtron. The detection limit is equivalent up to 3·10−13 g of232Th and 7·10−14 of237Np. The method was used to determine232Th and237Np isotopes in water samples.

The present paper deals with the determination of the thorium, uranium, plutonium and neptunium concentrations by the track method using the (γ, f) reaction.

Techniques for the instrumental activation analysis of the chlorine content of coal using γ-rays, microtron photoneutrons and neutrons from a 252Cf source are described. Yields from the reaction 35Cl(γ, n)34mCl are determined at electron energies between 14 and 21 MeV. The chlorine detection limit in coal reaches the value 5 × 10−4% in the case of γ-activation analysis and 0.2% for a 252Cf neutron source (5 × 107 n/s). Es werden Methoden der instrumentellen Aktivierungsanalyse zur Bestimmung des Chlor-Gehaltes in Kohln unter Verwendung von γ-Strahlen, Mikrotron-photoneutronen und von Neutronen aus einer 252Cf-Quelle beschrieben. Die Ausbeuten bei der Reaktion 35Cl(γ, n)34ZCl werden bei Elektronenenergien im Bereich 14 und 21 MeV bestimmt. Die Nachweisgrenzen von Chlor in Kohlen reicht bis zu 5 · 10−4% im Falle der γ-Aktivierungsanalyse und 0,2% bei Anwendung einer 252Cf-Neutronenquelle (bei 5 · 107 Neutronen · 8−1).