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“Off-the-shelf” clinical linear electron accelerators (LINAC) have been suggested as alternative to research accelerators once they are no longer suitable for the medical applications. We investigated feasibility of utilising a modified LINAC for instrumental photon activation analysis (IPAA) as a tool in environmental geochemistry studies. The IPAA results were compared with those obtained using a MT-25 research accelerator at Joint Institute for Nuclear Research in Dubna, Russia. To investigate soil pollution in Antalya, Turkey, 90 surface soil samples were analysed and significant enrichments of Ni, Cr and As were found.

This work presents the experimental study of the isomeric ratio of 137mCe–137gCe produced in 138Ce(γ, n) 137m,gCe photonuclear reaction, in neutron capture reaction 136Ce(n, γ) 137m,gCe and in the two simultaneous reactions 138Ce(γ, n) 137m,gCe and 136Ce(n, γ) 137m,gCe in the mixed photon—neutron field by the activation method. The investigated samples were irradiated at the bremsstrahlung photon flux, in the epithermal and thermal-epithermal neutron beam and in the mixed photon-neutron field constructed at the electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia. The results were analyzed, discussed and compared with those of other authors to examine the role of the channel effect in nuclear reaction and provide the nuclear data for theoretical model interpretation of nuclear reactions.

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 isomeric ratios in 138Ce(γ, n)137m,gCe photonuclear reaction have been measured for energy ranges from 14 to 17, 21 to 23 and at 19 MeV end-point bremsstrahlung energies by the activation method. In order to improve the accuracy of the experimental results, necessary corrections and data analysis were made in the γ-ray activity measurements. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy and the influence of channel effects. The above obtained data are the first time measurements.

The paper reports on the observation of spontaneous fission of nuclides, concentrated in fly ash during the combustion of high-carbon (graphite) material, chemogenic siliceous-carbonaceous rocks and carbonaceous shale in the mixture with brown coal. In the samples obtained, the spontaneous fission was measured by track method. The zones of precipitation of spontaneous fission of nuclides and their lighter homologues on thermochromatographic column were determined. A nuclide with a half-life of 62 days was detected in the alkaline trap. The chemical treatment procedure included co-precipitation with iron hydroxide, dissolution in NH4OH + H2O2 solution and distillation by heating up to 100°C followed by AgI co-precipitation. Based on the chemical behavior it can be concluded that the detected radionuclide belongs to the halides. The content of the parent nuclide in high-carbon (graphite) material and chemogenic siliceous-carbonaceous rock corresponds to 10–14 g/g.

The paper reports on the observation of the spontaneously fissioning nuclides as a result of hydrochemical and high-temperature processing of iron-manganese nodules. The spontaneous fission in the samples obtained was measured by the track method using electrochemical etching, and nuclides with T1/2 = 15 d, T1/2 = 25 d that is similar in chemical properties to Os and T1/2 = 62 d, (similar in chemical properties to Pb and Ra) were detected. The content of the parent nuclide in iron-manganese nodules corresponds to 4 × 10−14−8 × 10−14 g/g.

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.

In this paper we have studied the possibility of determining the chemical elements in coal samples using X-ray fluorescence analysis and have found a relationship between the coal calorific value and its ash content with the coal moisture accounting. The amount of coal ash can be determined by the content of the basic chemical elements, such as Si, Sr, Fe, and Ca. It was concluded that the calorific value of coal can be estimated from the ash content in coal without the calorimetric measurements. These correlation coefficients were calculated for coal from several coal mines in Mongolia. The results are in good agreement with the results of chemical analysis.

We measured for the first time the isomeric ratios in 107Ag(γ, n)106m,gAg reaction by using the activation method and γ-ray spectroscopic method for the whole giant dipole resonance region. The high-purity natural Ag foils in disc shape were irradiated with bremsstrahlungs generated from an electron accelerator Microtron. The induced gamma spectra in the irradiated foils were measured by the high resolution γ-ray spectroscopic system which consists of a high-purity germanium detector and a multichannel analyzer. In order to improve the accuracy of the experimental results, necessary corrections were made in the γ-ray activity measurements and data analysis. The results were analyzed, discussed and compared with those of other authors. For the above mentioned reaction, the isomeric ratios in the energy range from 14 to 24 MeV bremsstrahlungs in this work (except the values at 14, 18 and 20) are new measurements.

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.

We have determined the total bremsstrahlung photon fluxes with end-point energies in the giant dipole resonance (GDR) region produced by electron accelerator Microtron MT—25 (the Flerov Laboratory of Nuclear Reaction, Joint Institute for Nuclear Research, Dubna, Russia) and that of 65 MeV bremsstrahlung produced by the linear electron accelerator (the Pohang Neutron Facility, Pohang, South Korea). The method that we used was the photon activation technique. To ensure the accuracy of the results, we carried out simultaneous photon activation of two monitors made of Cu and Au foils in the same irradiation conditions. The results are discussed in the paper.

We have determined the isomeric ratios in 113In(γ, n)112m,gIn and 113In(γ, 2n)111m,gIn 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.

The leaves, stem, and roots of two types of shrubs (tea (Camellia sinensis) and sweet leaf (Sauropus androgynus)) and two types of herbs (vetiver grass (Vetiveria zizanioides L. Nash) and maize (Zea mays L)) and the Thucuc soil where the plants were growing were collected to be studied. The contents of 22 elements in the samples were determined by three methods: X-Ray fluorescence analysis (XRFA), gamma activation analysis (GAA), and the tracking method to study the distribution of these elements in plants and the soil-plant relationship. This study was carried out at the Flerov Laboratory of Nuclear Reactions (FLNR), Joint Institute for Nuclear Research (JINR), Dubna, Russia. The distribution of the elements in the soil-plant system was studied.

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 yields of 135Cs nuclei in a high-spin (19/2) isomeric state and of nuclei neighboring it were measured for photonuclear reactions of the (γ, f) and (γ, α) types. The experiments in question were performed by using bremsstrahlung from a microtron at the maximum electron energy of 25 MeV. The product nuclei were identified by their half-lives and by the lines of gamma radiation emitted in their decay, and the reaction yields R were determined by the ratios of the intensities of these lines to the bremsstrahlung flux. The cross sections for isomer production were calculated, and the angular momenta of product nuclei immediately before the cascade of gamma transitions populating the ground or an isomeric nuclear state were evaluated on the basis of these results. An enhanced yield of the high-spin isomer of 135Cs in the fission reaction in relation to the respective (γ, α) reaction and in relation to the results of the calculations is found.

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.

The release of trace metals from oil industry in ecosystems represents a serious hazard for the Biosphere, because of their toxicity. The objective of the study is to identify the source and evaluate the effect of key contaminants and other toxic and non-toxic bioactive elements as well as to provide the basis for improved health for human population by the use of instrumental gamma-activation analysis in combination with the X-ray fluorescence technique. The analytical work consisted in measuring trace concentrations of specific oil industry pollutants in soil and river sediments from the region of oil refinery industry in Ploiesti city, Romania. A highly sensitive photon neutron activation method based on the (γ, n) reactions for determining the concentrations of trace heavy metals in the environmental samples is applied. Additionally, the replicate samples were investigated by the X-ray fluorescence analysis. Further the results were used to develop an approach based on the geostatistical modelling to update the estimates of heavy metal concentrations on the ground in order to quantify their extent in the region in relation with the emission sources.

We have determined the isomeric ratios in photonuclear reactions 116Cd(γ, n)115m, g Cd, 138Ce(γ, n)137m, g Ce, 153Eu(γ, n)152m, g Eu, 96Mo(γ, p)95m, g Nb, 118Sn(γ, p)117m, g In, 89Y(γ, 2n)87m, g Y, 106Cd(γ, np)104m, g Ag, and 112Sn(γ, np)110m, g In induced by bremsstrahlungs with end-point energies in the Giant Dipole Resonance (GDR) region. The targets were irradiated at electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna. Gamma spectra of irradiated samples were measured with a spectroscopic system consisting of 8192-channel analyzer and high-energy resolution (180 keV at gamma ray 1332 keV of 60Co) semiconductor detector CANBERRA. The results were discussed and compared with those of other authors.

Bremsstrahlung emission, or radiation loss, is the dominant mechanism of energy dissipation of electrons at relativistic energies greater than a few MeV when it is subjected to acceleration in the field of the nucleus or of the electrons. In this study, the Monte Carlo calculations for bremsstrahlung spectra have been described for the case of a thick tungsten target with incident electron beams from 10 to 50 MeV, where secondary interactions induced by the electrons and photons in the target, such as energy loss, absorption, scattering, and (e+, e−)-pair production effects, were taken into account.

We have carried out the study on the isomeric ratios in (γ,p) photonuclear reactions with isotopes 40 92 Zr and 74 183 W in the giant dipole resonance (GDR) region. The targets were irradiated with bremsstrahlungs produced by electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia. Spectra of the irradiated samples were measured with a spectroscopic system consisting of 8192-channel analyzer CANBERRA and high-energy resolution semiconductor detector CANBERRA. The results were discussed and compared with those of other authors.

More than 130 samples of Tertiary phonolitic, trachytic and trachyandesitic rocks, representing evolved members of strongly and weakly alkaline volcanic rock series of the Ohre (Eger) Rift in the Bohemian Massif, Czech Republic, were analysed by instrumental neutron and photon activation analysis (INAA and IPAA, respectively). Forty-two major and trace elements were determined to explain the origin of such evolved rocks. Specific features of INAA and IPAA of the silicic, highly alkaline rocks are discussed, and results for selected samples are given. Plus de cent trente echantillons de phonolites, de trachytes et de trachy andesites tertiaires ont ete analyses par analyse des neutrons ou des photons induits par activation (INAA et IPAA respectivement). Ces roches volcaniques differenciees appartiennent a des series faiblement alcalines a alcalines du Rift Ohre (Eger) situe dans le Massif de Boheme (Republique Tcheque). Quarante deux elements majeurs et en trace ont ete determines afin d'expliquer l'origine de ces roches evoluees. Les caracteristiques specifiques de l'INAA et l'IPAA appliquees a des roches riches en silice et tres alcalines sont discutees et les resultats obtenus sur les echantillons selectionnes sont donnes.

We have carried out a study on the isomeric ratio in the 197Au(γ, n)196m,gAu photonuclear reaction in a giant dipole resonance region with bremsstrahlungs produced by electron accelerator Microtron MT-25 of the Flerov Laboratory of Nuclear Reactions, JINR. The isomeric ratio has been determined from a series of gamma spectra measured with a high-energy-resolution gamma spectrometric system consisting of an HPGe detector and a multichannel analyzer. The results have been discussed, compared with those of other authors, as well as considered by the statistical model supposed by Huizenga and Vandenbosch.

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.

Twenty six elements was studied preliminary i n the superficial sediments of Havana Bay using gamma activation analysis by the electron accelerator microtron MT -25 at the Flerov Laboratory of Nuclear Reactions, JINR. Samples from five zones of Havana Bay including the three coves were analyzed. The ob tained results show a close relation between the concentration levels of the studied elements and the pollution sources. Some elements (As, Ba, Ni, Pb, Cu, Zn, Fe, Cr, Mn) have high concentration levels compared to the values for other environmental marine sediments reported in the literature.

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.

The electrophoretic method was recently developed for the determination of diffusion coefficients of ions in aqueous solution. By solving the Fick's second law in the presence of unlimited media and constant quantity of diffusing species we obtain a relationship between the diffusion coefficient and the standard deviation of the distribution profile. The diffusion coefficients of Cd(II), In(III), Zr(IV), Hf(IV), Pu(VI) and [InDTPA]2− in nitric acid solution were determined as well as the effective charge of In-DTPA complex at pH 4.50.

Summary The measurement of the chemical reaction rates for complex formation as well as hydrolysis type reactions by the method of horizontal zone electrophoresis is outlined. The correlation between chemical equilibrium kinetics and electrodiffusion processes in a constant d.c. electric field is described. In model electromigration experiments the reaction rate constant of the formation a complex by Hf(IV) and diethylenetriaminepentaacetic acid (DTPA) is determined. The electrophoretic mobility, diffusion coefficient and stability constant of the [HfDTPA]- complex are calculated, taking into account experimental electrophoretic data obtained at 298.15±0.05K and constant ionic strength. No-carrier-added 175Hf radionuclide was used in electromigration experiments at concentrations of 10-10-10-11M.

Precise measurement of the anomalous g-value, am ¼ð g � 2Þ=2; of the negative muon boundin an atom provid es a sensitive test on the validity of: (1) the relativistic correction to g; (2) the quantum electrodynamics correction in a strong Coulomb fieldof the nucleus. In this work the magnetic moment of the negative muon in the 1s-state of Zn and Cd atoms was measured. A substantial deviation of the experimental data from the results of theoretical calculations is found. Possible reasons of this disagreement are discussed. r 2002 Elsevier Science B.V. All rights reserved.

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].

The electrophoretic behavior of the 111 In -DTPA radiopharmaceutical has been investigated. The stability constant, diffusion coefficient and effective charge of the complex as well as the temperature dependence of the electrophoretic mobility were determined. No-carrier-added 111 In with high specific activity was used in the electrophoretic experiments in ultramicroconcentrations (10 −9 M ) .

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%.

Sorption of U(VI) with soil from the region of location of the radioactive waste repository was studied. The radionuclide 237U produced by the photonuclear reaction 238U(γ, n)237U on an electron accelerator, MT-25 microtron (FLNR, JINR), was used as tracer. The U(VI) speciation in solution at various U concentrations was calculated in the range pH 1–7 using the Speciation program.

225Ac was prepared by the 226Ra(γ, n) reaction on an electron accelerator (MT-25 microtron) at FLNR. The radiation yield of 225Ac was 550 Bq/(μA h mg 226Ra). 225Ac was isolated from the target material and radioactive impurities by the ion-exchange procedure. The 225Ac:227Ac:226Ra activity ratio in the preparation was 1:∼2 × 10−9:≤6 × 10−5.

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 effect of stress factors (small doses of radiation and maximum temperatures in the econiche of the tested plants (tmax)) as well as aging on pea seeds, both acting independently and in combination, is estimated. Here we evaluate the influence of oxidizing stress on pea seeds in the laboratory (gamma-irradiated with 7 cGy at 0.3-19.1 cGy/h, tmax approximately 30-32 degrees C) and on natural plantain seeds collected in a 30-km zone of NPP (radiation exposure approximately 15 R/h, tmax approximately 38-40 degrees C). We have mathematically modeled CAs frequencies in root seedlings meristeme by invoking an enhancing factor transmitted from cell to cell. It is shown under the stress conditions: 1) CA frequency decreases whereas the fraction of inviable seeds (IS) increases, the dependence of IS on CA frequency being inversed; 2) a stimulation of proliferation of cell was observed; 3) a bystander effect appears; 4) antioxidative status (AOS) of seeds influences on adaptation on the all levels of the organization; 5) IS increases up to 73-80% under the combined effect of radiation and heat stresses.