730 research outputs found

    Search for α\alpha decay of 151^{151}Eu to the first excited level of 147^{147}Pm using underground γ\gamma-ray spectrometry

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    The alpha decay of 151^{151}Eu to the first excited level of 147^{147}Pm (Jπ=5/2+J^\pi = 5/2^+, Eexc=91.1E_{exc}=91.1 keV) was searched for at the HADES underground laboratory (500\approx 500 m w.e.). A sample of high purity europium oxide with mass of 303 g and a natural isotopic composition has been measured over 2232.8 h with a high energy resolution ultra-low background n-type semi-planar HPGe detector (40 cm3^3) with sub-micron deadlayer. The new improved half-life limit has been set as T1/23.7×1018T_{1/2} \geq 3.7\times 10^{18} yr at 68% C.L. Possibilities to improve the sensitivity of the experiment, which is already near the theoretical predictions, are discussed. New half-life limit for α\alpha decay of 153^{153}Eu is also set as T1/25.5×1017T_{1/2} \geq 5.5\times 10^{17} yr.Comment: 11 pages, 5 figures, 2 tables, 18 reference

    Correlative Microscopy: A Potent Tool for Biomedicine

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    The correlative microscopy method based on a combination of optical and electronic techniques that is increasingly widely used now, has a number of limitations. Here, an alternative approach is considered that uses scanning probe microscopy (SPM) technique to get high-resolution and ultra-high-resolution data. SPM greatly increases the possibilities of collecting new information (on topological, morphological, electrical, magnetic etc. properties). To obtain three-dimensional distributions of different parameters of the sample, ultramicrotomography is used, which allows to scan the sample in steps of up to 20 nm. The principal advantage of the approach is that spectral data are used which due to the combination in near field microscopy can be gained with high and ultrahigh resolution. All above mentioned features are implemented in a single instrument, which allows to have 3-D data and their distributions at the same instrumental platform. A special feature of the approach is the possibility to use all the power of micro(nano)spectral methods. Therefore, it would be more correct to name the proposed approach ”Correlative microspectroscopy”. Keywords: correlative microscopy, correlative microspectroscopy, scanning near-ielf optical microscopy, ultramicrotomography, Raman, TER

    Rejection of randomly coinciding events in ZnMoO4_4 scintillating bolometers

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    Random coincidence of events (particularly from two neutrino double beta decay) could be one of the main sources of background in the search for neutrinoless double beta decay with cryogenic bolometers due to their poor time resolution. Pulse-shape discrimination by using front edge analysis, mean-time and χ2\chi^2 methods was applied to discriminate randomly coinciding events in ZnMoO4_4 cryogenic scintillating bolometers. These events can be effectively rejected at the level of 99% by the analysis of the heat signals with rise-time of about 14 ms and signal-to-noise ratio of 900, and at the level of 92% by the analysis of the light signals with rise-time of about 3 ms and signal-to-noise ratio of 30, under the requirement to detect 95% of single events. These rejection efficiencies are compatible with extremely low background levels in the region of interest of neutrinoless double beta decay of 100^{100}Mo for enriched ZnMoO4_4 detectors, of the order of 10410^{-4} counts/(y keV kg). Pulse-shape parameters have been chosen on the basis of the performance of a real massive ZnMoO4_4 scintillating bolometer. Importance of the signal-to-noise ratio, correct finding of the signal start and choice of an appropriate sampling frequency are discussed

    On the possibility to search for double beta decay of initially unstable (alpha/beta radioactive) nuclei

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    Possibilities to search for double beta decay of alpha/beta unstable nuclei, many of which have higher energy release than "conventional" (beta stable) double beta decay candidates, are discussed. First experimental half-life limits on double beta decay of radioactive nuclides from U and Th families (trace contaminants of the CaWO_4, CdWO_4 and Gd_2SiO_5 scintillators) were established by reanalyzing the data of low-background measurements in the Solotvina Underground Laboratory with these detectors (1734 h with CaWO_4, 13316 h with CdWO_4, and 13949 h with Gd_2SiO_5 crystals).Comment: 15 pages, 6 figure

    БУСТЕРНАЯ СИСТЕМА ПИТАНИЯ В ЭЛЕКТРОТРАНСПОРТНЫХ СРЕДСТВАХ СЕЛЬСКОХОЗЯЙСТВЕННОГО НАЗНАЧЕНИЯ

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    This paper considers the possibility of using electric vehicles with booster devices. Justified their use in enclosed areas. The technique of determining the parameters of the booster unit and recommendations on the definition of the coefficient of energy consumption, depending on the time required mezhzaryadnoy work.В работе рассматривается возможность применения электротранспортных средств с бустерными устройствами. Обосновывается их применение в закрытых помещениях. Предлагается методика определения параметров бустерного устройства и даны рекомендации по определению коэффициента энергоемкости в зависимости от требуемого времени межзарядной работы.У роботі розглядається можливість вживання засобів електротранспорту з бустерними пристроями. Обгрунтовується їх вживання в закритих приміщеннях. Пропонується методика визначення параметрів бустерного пристрою і дани рекомендації за визначенням коефіцієнта енергоємності залежно від необхідного часу міжзарядної роботи. Ключові слова: гібрід, бустер, сільське господарств

    Rejection of randomly coinciding events in Li2_2100^{100}MoO4_4 scintillating bolometers using light detectors based on the Neganov-Luke effect

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    Random coincidences of nuclear events can be one of the main background sources in low-temperature calorimetric experiments looking for neutrinoless double-beta decay, especially in those searches based on scintillating bolometers embedding the promising double-beta candidate 100^{100}Mo, because of the relatively short half-life of the two-neutrino double-beta decay of this nucleus. We show in this work that randomly coinciding events of the two-neutrino double decay of 100^{100}Mo in enriched Li2_2100^{100}MoO4_4 detectors can be effectively discriminated by pulse-shape analysis in the light channel if the scintillating bolometer is provided with a Neganov-Luke light detector, which can improve the signal-to-noise ratio by a large factor, assumed here at the level of 750\sim 750 on the basis of preliminary experimental results obtained with these devices. The achieved pile-up rejection efficiency results in a very low contribution, of the order of 6×105\sim 6\times10^{-5} counts/(keV\cdotkg\cdoty), to the background counting rate in the region of interest for a large volume (90\sim 90 cm3^3) Li2_2100^{100}MoO4_4 detector. This background level is very encouraging in view of a possible use of the Li2_2100^{100}MoO4_4 solution for a bolometric tonne-scale next-generation experiment as that proposed in the CUPID project

    High sensitivity double beta decay study of 116-Cd and 100-Mo with the BOREXINO Counting Test Facility (CAMEO project)

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    The unique features (super-low background and large sensitive volume) of the CTF and BOREXINO set ups are used in the CAMEO project for a high sensitivity study of 100-Mo and 116-Cd neutrinoless double beta decay. Pilot measurements with 116-Cd and Monte Carlo simulations show that the sensitivity of the CAMEO experiment (in terms of the half-life limit for neutrinoless double beta decay) is (3-5) 10^24 yr with a 1 kg source of 100-Mo (116-Cd, 82-Se, and 150-Nd) and about 10^26 yr with 65 kg of enriched 116-CdWO_4 crystals placed in the liquid scintillator of the CTF. The last value corresponds to a limit on the neutrino mass of less than 0.06 eV. Similarly with 1000 kg of 116-CdWO_4 crystals located in the BOREXINO apparatus the neutrino mass limit can be pushed down to m_nu<0.02 eV.Comment: 29 pages, LaTex, 9 eps figure

    The event generator DECAY4 for simulation of double beta processes and decay of radioactive nuclei

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    The computer code DECAY4 is developed to generate initial energy, time and angular distributions of particles emitted in radioactive decays of nuclides and nuclear (atomic) deexcitations. Data for description of nuclear and atomic decay schemes are taken from the ENSDF and EADL database libraries. The examples of use of the DECAY4 code in several underground experiments are described.Comment: 8 pages, 1 fi
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