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Information × Registration Number 0216U008241, 0116U005457 , R & D reports Title Study of double beta decay of atomic nuclei to the ground and excited levels of the daughter nuclei. popup.stage_title Head Danevich Fedor, Registration Date 15-12-2016 Organization Scientific Center "Institute for Nuclear Research" of National Academy of Sciences of Ukraine popup.description2 Processing of the data, accumulated by the detector NEMO-3 for more than 5 years of live time, allowed to determine the half-lives of nuclei 48Ca and 150Nd as T1/2=6.4x10^19 years and T1/2=9.3x10^18 years, respectively, for the two-neutrino mode of double beta decay to the ground states of the daughter nuclei. The probability of neutrinoless decay was limited for both nuclei at the level of T1/2>2.0x10^22 years for mass decay mechanism, and the following restrictions on the mass of the neutrino were obtained: m<6.0--26 eV (from the T1/2 limit of 48Ca) and m<1.6--5.3 eV (from the T1/2 limit of 150Nd). New restrictions on the neutrinoless double beta decay with majoron radiation for 48Ca and 150Nd were obtained. The development of low-temperature scintillating bolometric detectors based on crystals of lithium molybdate and zinc molybdate is continued; they are intended for a large-scale experiment to search for neutrinoless double beta decay of 100Mo with sensitivity to the Majorana neutrino mass at the level of inverted neutrino mass scheme, m~0.05 eV. Low temperature scintillation bolometric detectors with ZnMoO4 and Li2MoO4 crystals, grown with 100Mo enriched isotope, showed high spectrometric characteristics (energy resolution of 5.8 keV), the ability of effective separating the signals between beta particles (gamma rays) and alpha particles (which is important to reduce the background), high radiopurity of the crystals. Preparation of a pilot experiment is going on with the project sensitivity to the half-life at the level of lim T1/2~4x10^25 years, which corresponds to the sensitivity to neutrino mass at lim m~0.07--0.11 eV, with planned (in the next 5-7 years) construction of a large-scale experiment for the search for the neutrinoless double beta decay of 100Mo on the sensitivity level of lim m~0.02--0.05 eV, which is sufficient to test the inverted neutrino mass scheme. ? new phase of the experiment with a cadmium tungstate crystal scintillator with enriched 106Cd is started; the aim of the experiment is searching for double beta processes in 106Cd, in coincidence with two large volume CdWO4 scintillation detectors for gamma-rays that are emitted in most processes of double 106Cd beta decay. The data analysis and simulations of background are started. In particular, it is shown that the use of signal coincidences in the 106CdWO4 and CdWO4 detectors will significantly improve the sensitivity to the double neutrino process with electron capture and positron emission in 106Cd. Product Description popup.authors Бойко Роман Сергійович Даневич Федор Анатолiйович Зуєва Олена Володимирівна Кобичев Владислав Валерійович Кобичев Роман Владиславович Кобичева Лариса Миколаївна Кропив'янський Борис Миколайович Мокіна Валентина Михайлівна Пода Денис Валентинович Поліщук Оксана Григорівна Тимошенко Андрiй Iванович Третяк Володимир Iллч Черняк Дмитро Миколайович Шкурупій Олег Юрійович popup.nrat_date 2020-04-02 Close