V. V. Kobychev

Publications (114) View all

• Source

  Available from: Vladimir Tretyak

  Article: Astrophysical and cosmological problems of invisible mass and dark energy in the Universe

  P. Belli, L. A. Berdina, R. Bernabei, A. Bogdan, R. S. Boiko, A. Yu. Burgazli, F. Cappella, R. Cerulli, D. M. Chernyak, F. A. Danevich, [......], M. Tenconi, O. Torbaniuk, V. I. Tretyak, V. S. Tsvetkova, V. G. Vakulik, Ya. V. Vasiliev, A. Vasylenko, O. Vasylenko, V. I. Zhdanov, A. I. Zhuk
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  ABSTRACT: The Workshop on results of the Project Kosmomikrofizyka-2 (Astroparticle Physics) of the National Academy of Sciences (NAS) of Ukraine "Astrophysical and cosmological problems of invisible mass and dark energy in the Universe" was held on November 21-22, 2012 in the Institute for Nuclear Research, Kyiv, Ukraine (http://lpd.kinr.kiev.ua/kmf12). This Project was carried out during three years (2010-2012) by scientists from various universities and institutes of the National Academy of Sciences of Ukraine; it was a logical continuation of the previous scientific program of the NAS of Ukraine "Researches of structure and composition of the Universe, hidden mass and dark energy (Kosmomikrofizyka)" in 2007-2009. These programs were devoted to theoretical and experimental investigations in astronomy, astrophysics, cosmology, physics of atomic nuclei and particle physics, which are related with the problems of dark matter and dark energy in the Universe.
  04/2013;
• Source

  Available from: Matthias Laubenstein

  Article: Measurement of geo-neutrinos from 1353 days of Borexino

  G. Bellini, J. Benziger, D. Bick, G. Bonfini, D. Bravo, M. Buizza Avanzini, B. Caccianiga, L. Cadonati, F. Calaprice, P. Cavalcante, [......], R. B. Vogelaar, F. von Feilitzsch, J. Winter, M. Wojcik, A. Wright, M. Wurm, J. Xu, O. Zaimidoroga, S. Zavatarelli, G. Zuzel
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  ABSTRACT: We present a measurement of the geo--neutrino signal obtained from 1353 days of data with the Borexino detector at Laboratori Nazionali del Gran Sasso in Italy. With a fiducial exposure of (3.69 $\pm$ 0.16) $\times$ $10^{31}$ proton $\times$ year after all selection cuts and background subtraction, we detected (14.3 $\pm$ 4.4) geo-neutrino events assuming a fixed chondritic mass Th/U ratio of 3.9. This corresponds to a geo-neutrino signal $S_{geo}$ = (38.8 $\pm$ 12.0) TNU with just a 6 $\times$ $10^{-6}$ probability for a null geo-neutrino measurement. With U and Th left as free parameters in the fit, the relative signals are $S_{\mathrm{Th}}$ = (10.6 $\pm$ 12.7) TNU and $S_\mathrm{U}$ = (26.5 $\pm$ 19.5) TNU. Borexino data alone are compatible with a mantle geo--neutrino signal of (15.4 $\pm$ 12.3) TNU, while a combined analysis with the KamLAND data allows to extract a mantle signal of (14.1 $\pm$ 8.1) TNU. Our measurement of a reactor anti--neutrino signal $S_{react}$ = 84.5$^{+19.3}_{-18.9}$ TNU is in agreement with expectations in the presence of neutrino oscillations.
  03/2013;
• Source

  Available from: Matthias Laubenstein

  Article: CdWO4 crystal scintillators from enriched isotopes for double beta decayexperiments

  D. V. Poda, A. S. Barabash, P. Belli, R. Bernabei, R. S. Boiko, V. B. Brudanin, F. Cappella, V. Caracciolo, S. Castellano, R. Cerulli, [......], S. Nisi, R. B. Podviyanuk, O. G. Polischuk, A. P. Shcherban, V. N. Shlegel, D. A. Solopikhin, V. I. Tretyak, V. I. Umatov, Ya. V. Vasiliev, V. D. Virich
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  ABSTRACT: Cadmium tungstate crystal scintillators enriched in 106Cd and 116Cd were developed. The produced scintillators exhibit good optical and scintillation properties, and a low level of radioactive contamination. Experiments to search for double beta decay of 106Cd and 116Cd are in progress at the Gran Sasso National Laboratories of the INFN (Italy). Prospects to further improve the radiopurity of the detectors by recrystallization are discussed.
  Radiation Measurements 03/2013; · 1.18 Impact Factor
• Source

  Available from: Denys V. Poda

  Conference Proceeding: First results of the experiment to search for double beta decay of 116Cd with the help of enriched 116CdWO4 crystal.

  A.S. Barabash, P. Belli, R. Bernabei, F. Cappella, V. Caracciolo, S. Castellano, R. Cerulli, D.M. Chernyak, F.A. Danevich, E.N. Galashov, [......], V.V. Kobychev, S.I. Konovalov, M. Laubenstein, D.V. Poda, R.B. Podviyanuk, O.G. Polischuk, V.N. Shlegel, V.I. Tretyak, V.I. Umatov, Ya.V. Vasiliev
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  ABSTRACT: A low background experiment to search for the double beta decay of 116Cd is in progress at the Gran Sasso National Laboratories of the INFN (Italy) by using 116CdWO4 crystal scintillators (~1.2 kg) enriched in 116Cd to 82%. The energy resolution of the detector is FWHM ~ 5.5% at Q_2beta of 116Cd (2813 keV), the background rate is 0.28 counts/(yr*keV*kg) in the 2.7–2.9 MeV energy range. After ~1 kg*yr of data taking, half-life of 116Cd relatively the 2nu2beta decay was measured as T1/2 = (2.5 ± 0.5)*1e19 yr and the new improved limits on the 2beta decay of 116Cd to few excited levels of 116Sn were set at level of 1e20-1e21 yr. In particular, 2nu2beta transitions to 2+ states (2112 and 2225 keV) of 116Sn were restricted on the level of 1e20 yr, approximately one order of magnitude higher than those established previously.
  4th Int. Conf. “Current Problems in Nuclear Physics and Atomic Energy" (NPAE-Kyiv2012), September 03–07, 2012, Kyiv, Ukraine; 03/2013
• Article: Scintillation properties and internal background study of 40Ca100MoO4 crystal scintillators for neutrino-less double beta decay search

  H.J. So, H.J. Kim, V.V. Alenkov, A.N. Annenkov, H. Bhang, R.S. Boiko, O.A. Buzanov, D.M. Chernyak, J.H. Choi, S. Choi, [......], S.I. Panasenko, D.V. Poda, R.B. Podviyanuk, O.G. Polischuk, S.S. Ratkevich, Y. Satou, K. Tanida, V.I. Tretyak, S.P. Yakimenko, Q. Yue
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  ABSTRACT: Scintillation properties and radioactive contamination of calcium molybdate scintillating crystals depleted in 48Ca and enriched in 100Mo (40Ca100MoO4 ) have been studied to prepare a 100Mo-based neutrinoless double beta decay experiment. The prospects of a neutrinoless double beta decay experiment using 40Ca100MoO4 crystals are discussed.
  IEEE Transactions on Nuclear Science 10/2012; 59(5):2214 - 2218. · 1.45 Impact Factor