129 research outputs found

    Monitoring of emission of particulate matter and air pollution using lidar in Belgorod, Russia

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    We demonstrate how lidar can be applied to optimize a particulate matter emissions monitoring network for environmental policy makin

    Improvement of radiopurity level of enriched 116^{116}CdWO4_4 and ZnWO4_4 crystal scintillators by recrystallization

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    As low as possible radioactive contamination of a detector plays a crucial role to improve sensitivity of a double beta decay experiment. The radioactive contamination of a sample of 116^{116}CdWO4_4 crystal scintillator by thorium was reduced by a factor 10\approx 10, down to the level 0.01 mBq/kg (228^{228}Th), by exploiting the recrystallization procedure. The total alpha activity of uranium and thorium daughters was reduced by a factor 3\approx 3, down to 1.6 mBq/kg. No change in the specific activity (the total α\alpha activity and 228^{228}Th) was observed in a sample of ZnWO4_4 crystal produced by recrystallization after removing 0.4\approx 0.4 mm surface layer of the crystal.Comment: 14 pages, 5 figures and 2 table

    Use of electron linac for study of fission product and actynide diffusion through glass ceramic matrices

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    The diffusion of cerium and uranium was investigated in glass ceramic matrices obtained in the gasostat. For activation of isotopes ¹⁴⁰´¹⁴²Се and ²³⁸U the brake radiation from electrons of the linear accelerator was used. The threshold of detectability of elements was reached from 5 to 15 µg/g for a sample of the area 1 cm². The coefficients of diffusion in the grain material and at grain boundaries were measured, and their values for the pressing temperature of 910°С and pressure 100~МPa were 3.5⋅10⁻⁹ cm²/s in the grain and 1.2⋅10⁻⁸ cm²/s at grain boundaries.Методом зняття шарів вивчена дифузія церію й урану в синтезовані за допомогою газостатического пресування склокерамічної матриці. Для активації ізотопів ¹⁴⁰´¹⁴²Се і ²³⁸U використовувалося гальмове випромінювання від електронів лінійного прискорювача. Межа виявлення ізотопів церію й урану становила 10⁻⁵ г/г. Були вимірювані коефіцієнти дифузії в матеріалі зерна і по границях, що при температурі пресування 910°С і тиску 100 МПа склали 3,5⋅10⁻⁹ см²/с у зерні і 1,2⋅10⁻⁸ см²/с по границях зерен.Методом снятия слоев изучена диффузия церия и урана в синтезированные посредством газостатического прессования стеклокерамические матрицы. Для активации изотопов ¹⁴⁰´¹⁴²Се и ²³⁸U использовалось тормозное излучение от электронов линейного ускорителя. Предел обнаружения изотопов церия и урана составил 10⁻⁵ г/г. Были измерены коэффициенты диффузии в материале зерна и по границам, которые при температуре прессования 910°С и давлении 100 МПа составили 3,5⋅10⁻⁹ см²/с в зерне и 1,2⋅10⁻⁸ см²/с по границам зерен

    Nuclear-physical methods of analysis of noble metals and rare-earth elements

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    A summary of the analysis noble and rare metals by combined methods is presented. The electrodeposition of gold at a carbon film and Rutherford backscattering was used for determination its in ores. The sorbents and particle induced X-ray emission was used for determination rare and noble metals in ores. The minimum detectable concentration for ores was 0.1 mg/g

    The dynamics of element content in patients with lung cancer during radiotherapy

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    Determination of the element contents in the biological samples (blood, serum of blood, hair) of patients with the diagnosis of lung cancer III degree is carried out during beam therapy. The method of PIXE excited by protons on the accelerator with energy 3 MeV has been used. During radiotherapy the difference in the element contents in hair of patients has not been detected. Trustworthy reduction of Fe, Cu, Mn, Ca, Sr, Rb etc is marked during treatment. The obtained results can be used as the additional test at carrying out adequate treatment in radiotherapy.Проведено визначення вмiсту мiкроелементiв в бiологiчних зразках (кров, сироватка кровi, волосся) пацiєнтiв з дiагнозом раку легенi III ступеня в процесi променевої терапiї. Використовувався метод характеристичного рентгенiвського випромiнювання, яке збуджувалось протонами прискорювача з енергiєю 3 МеВ. Протягом радiотерапiї вiдмiнностей у вмiстi елементiв у волоссях пацiєнтiв виявлено не було. У процесi лiкування вiрогiдно виявлене зменшення Fe, Cu, Mn, Ca, Sr, Rb i т.д. в кровi i сироватцi кровi. Отриманi результати можуть бути використанi як додатковий тест при проведеннi адекватної терапiї в курсi променевого лiкування.Проведено определение содержания микроэлементов в биологических образцах (кровь, сыворотка крови, волосы) пациентов с диагнозом рака легкого III степени в процессе лучевой терапии. Использован метод характеристического рентгеновского излучения, возбуждаемого протонами на ускорителе с энергией 3 МэВ. В течение радиотерапии отличий в содержании элементов в волосах пациентов обнаружено не было. В процессе лечения достоверно обнаружено уменьшение Fe, Cu, Mn, Ca, Sr, Rb и т.д. в крови и сыворотке крови. Полученные результаты могут быть использованы в качестве дополнительного теста при проведении адекватной терапии в курсе лучевого лечения

    C-H FUNCTIONALIZATION IN THE SYNTHESIS OF CARBORANE-BASED POLYAZAHATEROCYCLIC HYDROCARBONS

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    Among the versatile organic fluorophores, special attention is known to be paid to photoactive organoboron compounds, in particular heterocyclic derivatives of carborane. According to numerous studies, the ortho-carborane scaffold is considered to be an “element-block” for preparing solid state luminescent materials due to its excellent suppression of aggregation-caused quenching (ACQ). Carborane-based materials also currently find an application in catalysis, medicine, supramolecular chemistry and photovoltaics.The research was financially supported by the Russian Science Foundation (Project no. 20-43-01004), a bilateral Russian Science Foundation (RSF) – Fund for Scientific Research Flanders (FWO) project, and the Francqui Foundation

    Application of gamma activation analysis for research of Cs and I diffusion into a glassceramic matrix

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    Nuclear reactions ¹³³Cs(γ,n)¹³²Cs, ¹²⁷I(γ,n)¹²⁶I were utilized for research of Cs and I diffusion in glassceramic matrices. The glassceramic matrix was manufactured with the help of hot isostatic pressing at 910°C and pressure 100 MPa. Diffusivities of cesium and iodine in a grain and through interphase boundary at 600°C were equal 10⁻¹¹ and 7.9⋅10⁻⁹ sm²/s, accordingly. The decrease of iodine diffusivity in a grain was observed at 750°C. A method of manufacture of glassceramic matrix for long-lived storage and nuclear-waste disposal ¹²⁹I is proposed.Ядерные реакции ¹³³Cs(γ,n)¹³²Cs, ¹²⁷I(γ,n)¹²⁶I использовались для исследования диффузии Cs и I в стеклокерамической матрице. Стеклокерамическая матрица изготовлена при помощи газостатического прессования при 910°С и давлении 100 МПа. Коэффициенты диффузии цезия и йода в зерне и по границам зерен при 600°С составили 10⁻¹¹ и 7,9⋅10⁻⁹ см²/с, соответственно. Обнаружено уменьшение коэффициента диффузии йода в зерне при 750°С. Предложен способ создания матрицы для захоронения ¹²⁹I.Ядерні реакції ¹³³Cs(γ,n)¹³²Cs, ¹²⁷I(γ,n)¹²⁶I використовувалися для дослідження дифузії Cs та I у склокерамічній матриці. Склокерамічна матриця виготовлена за допомогою газостатичного пресування при 910°С і тиску 100 МПа. Коефіцієнти дифузії цезію і йоду в зерні і по границях зерен при 600° С склали 10⁻¹¹ та 7,9⋅10⁻⁹ см²/с, відповідно. Виявлено зменшення коефіцієнта дифузії йоду в зерні при 750°С. Запропоновано спосіб створення матриці для поховання ¹²⁹I

    Li2_2100depl^{100\textrm{depl}}MoO4_4 Scintillating Bolometers for Rare-Event Search Experiments

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    We report on the development of scintillating bolometers based on lithium molybdate crystals containing molybdenum depleted in the double-β\beta active isotope 100^{100}Mo (Li2_2100depl^{100\textrm{depl}}MoO4_4). We used two Li2_2100depl^{100\textrm{depl}}MoO4_4 cubic samples, 45 mm side and 0.28 kg each, produced following purification and crystallization protocols developed for double-β\beta search experiments with 100^{100}Mo-enriched Li2_2MoO4_4 crystals. Bolometric Ge detectors were utilized to register scintillation photons emitted by the Li2_2100depl^{100\textrm{depl}}MoO4_4 crystal scintillators. The measurements were performed in the CROSS cryogenic set-up at the Canfranc underground laboratory (Spain). We observed that the Li2_2100depl^{100\textrm{depl}}MoO4_4 scintillating bolometers are characterized by excellent spectrometric performance (\sim3--6 keV FWHM at 0.24--2.6 MeV γ\gamma's), moderate scintillation signal (\sim0.3--0.6 keV/MeV depending on light collection conditions) and high radiopurity (228^{228}Th and 226^{226}Ra activities are below a few μ\muBq/kg), comparable to the best reported results of low-temperature detectors based on Li2_2MoO4_4 with natural or 100^{100}Mo-enriched molybdenum content. Prospects of Li2_2100depl^{100\textrm{depl}}MoO4_4 bolometers for use in rare-event search experiments are briefly discussed.Comment: Prepared for submission to MDPI Sensors; 16 pages, 7 figures, and 3 table

    Final results on the 0νββ decay half-life limit of 100^{100} Mo from the CUPID-Mo experiment

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    The CUPID-Mo experiment to search for 0νββ decay in 100^{100}Mo has been recently completed after about 1.5 years of operation at Laboratoire Souterrain de Modane (France). It served as a demonstrator for CUPID, a next generation 0νββ decay experiment. CUPID-Mo was comprised of 20 enriched Li2100_2^{100}MoO4_4 scintillating calorimeters, each with a mass of ∼0.2 kg, operated at ∼20 mK. We present here the final analysis with the full exposure of CUPID-Mo (100^{100}Mo exposure of 1.47 kg×year) used to search for lepton number violation via 0νββ decay. We report on various analysis improvements since the previous result on a subset of data, reprocessing all data with these new techniques. We observe zero events in the region of interest and set a new limit on the 100^{100}Mo 0νββ decay half-life of T1/20ν^{0ν}_{1/2} >1.8×1024^{24} year (stat. + syst.) at 90% CI. Under the light Majorana neutrino exchange mechanism this corresponds to an effective Majorana neutrino mass of ⟨mββ_{ββ}⟩ < (0.28−0.49) eV, dependent upon the nuclear matrix element utilized
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