Персона:
Козлов, Александр Анатольевич

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Цель ИЯФиТ и стратегия развития - создание и развитие научно-образовательного центра мирового уровня в области ядерной физики и технологий, радиационного материаловедения, физики элементарных частиц, астрофизики и космофизики.

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Козлов

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Александр Анатольевич

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Теперь показываю 1 - 10 из 10

Только метаданные
A Passive Shield for the RED-100 Neutrino Detector
(2021) Efremenko, Y. V.; Akimov, D. Y.; Aleksandrov, I. S.; Belov, V. A.; Bolozdynya, A. I.; Etenko, A. V.; Galavanov, A. V.; Gouss, D. V.; Gusakov, Y. V.; Kdib, D. E.; Khromov, A. V.; Konovalov, A. M.; Kornoukhov, V. N.; Kovalenko, A. G.; Kozlov, A. A.; Kozlova, E. S.; Kumpan, A. V.; Lukyashin, A. V.; Pinchuk, A. V.; Razuvaeva, O. E.; Rudik, D. G.; Shakirov, A. V.; Simakov, G. E.; Sosnovtsev, V. V.; Vasin, A. A.; Акимов, Дмитрий Юрьевич; Александров, Иван Сергеевич; Белов, Владимир Александрович; Болоздыня, Александр Иванович; Этенко, Александр Владимирович; Галаванов, Андрей Владиевич; Гусс, Дмитрий Викторович; Гусаков, Юрий Васильевич; Хромов, Александр Владимирович; Коновалов, Алексей Михайлович; Корноухов, Василий Николаевич; Коваленко, Алексей Григорьевич; Козлов, Александр Анатольевич; Козлова, Екатерина Сергеевна; Кумпан, Александр Вячеславович; Лукьяшин, Антон Викторович; Пинчук, Артём Валентинович; Разуваева, Ольга Евгеньевна; Рудик, Дмитрий Геннадьевич; Шакиров, Алексей Вячеславович; Симаков, Григорий Евгеньевич; Сосновцев, Валерий Витальевич; Васин, Антон Андреевич
© 2021, Pleiades Publishing, Ltd.Abstract—: A combined passive shield of the RED-100 two-phase emission neutrino detector has been developed and built for suppressing the background of external γ rays and neutrons. The shield is composed of a 5‑cm-thick copper layer (the inner layer is adjacent to the detector) and a water layer with a total thickness of approximately 70 cm (including the water inside the copper shield). The Monte Carlo simulation of the shielding efficiency has been performed. The obtained attenuation factor of the copper shield for the γ-ray background has been experimentally verified in a laboratory test using a NaI(Tl) scintillator detector. The γ‑ray background rejection factor of the full shield has also been calculated.
Только метаданные
Search for Low-energy Electron Antineutrinos in KamLAND Associated with Gravitational Wave Events
(2021) Abe, S.; Asami, S.; Gando, A.; Gando, Y.; Kozlov, A.; Козлов, Александр Анатольевич
We present the results of a search for MeV-scale electron antineutrino events in KamLAND coincident with the 60 gravitational wave events/candidates reported by the LIGO/Virgo collaboration during their second and third observing runs. We find no significant coincident signals within a 500 s timing window from each gravitational wave and present 90% C.L. upper limits on the electron antineutrino fluence between 10(8) and 10(13) cm(-2) for neutrino energies in the energy range of 1.8-111 MeV.
Только метаданные
The nylon balloon for xenon loaded liquid scintillator in KamLAND-Zen 800 neutrinoless double-beta decay search experiment
(2021) Gando, Y.; Gando, A.; Hachiya, T.; Kozlov, A.; Козлов, Александр Анатольевич
© 2021 IOP Publishing Ltd and Sissa Medialab.The KamLAND-Zen 800 experiment is searching for the neutrinoless double-beta decay of 136Xe by using 136Xe-loaded liquid scintillator. The liquid scintillator is enclosed inside a balloon made of thin, transparent, low-radioactivity film that we call Inner Balloon (IB). The IB, apart from guaranteeing the liquid containment, also allows to minimize the background from cosmogenic muon-spallation products and 8B solar neutrinos. Indeed these events could contribute to the total counts in the region of interest around the Q-value of the double-beta decay of 136Xe. In this paper, we present an overview of the IB and describe the various steps of its commissioning minimizing the radioactive contaminations, from the material selection, to the fabrication of the balloon and its installation inside the KamLAND detector. Finally, we show the impact of the IB on the KamLAND background as measured by the KamLAND detector itself.
Только метаданные
PICOLON dark matter search project
(2022) Fushimi, K.; Chernyak, D.; Ejiri, H.; Hata, K.; Kozlov, A. A.; Козлов, Александр Анатольевич
© 2022 Institute of Physics Publishing. All rights reserved.PICOLON (Pure Inorganic Crystal Observatory for LOw-energy Neutr(al)ino) aims to search for cosmic dark matter by high purity NaI(Tl) scintillator. We developed extremely pure NaI(Tl) crystal by hybrid purification method. The recent result of 210Pb in our NaI(Tl) is less than 5.7 µBq/kg. We will report the test experiment in the low-background measurement at Kamioka Underground Laboratory. The sensitivity for annual modulating signals and finding dark matter particles will be discussed.
Только метаданные
Low-energy astrophysics with KamLAND
(2022) Kawada, N.; Obara, S.; Ishidoshiro, K.; Abe, S; Kozlov, A.; Козлов, Александр Анатольевич
Только метаданные
Limits on Astrophysical Antineutrinos with the KamLAND Experiment
(2022) Abe, S.; Asami, S.; Gando, A.; Gando, Y.; Kozlov, A.; Козлов, Александр Анатольевич
We report on a search for electron antineutrinos ((nu) over bar (e)) from astrophysical sources in the neutrino energy range 8.3-30.8 MeV with the KamLAND detector. In an exposure of 6.72 kton-year of the liquid scintillator, we observe 18 candidate events via the inverse beta decay reaction. Although there is a large background uncertainty from neutral current atmospheric neutrino interactions, we find no significant excess over background model predictions. Assuming several supernova relic neutrino spectra, we give upper flux limits of 60-110 cm(-2) s(-1) (90% confidence level, CL) in the analysis range and present a model-independent flux. We also set limits on the annihilation rates for light dark matter pairs to neutrino pairs. These data improve on the upper probability limit of B-8 solar neutrinos converting into (nu) over bar (e), P-nu e ->nu e < 3.5 x 10(-5) (90% CL) assuming an undistorted <(nu)over bar>(e) flux of 60 cm(-2) s(-1) (90% CL) in the analysis energy range.
Только метаданные
Search for Solar Flare Neutrinos with the KamLAND Detector
(2022) Collaboration, K.; Abe, S.; Asami, S.; Gando, A.; Kozlov, A.; Козлов, Александр Анатольевич
© 2022. The Author(s). Published by the American Astronomical Society.We report the result of a search for neutrinos in coincidence with solar flares from the GOES flare database. The search was performed on a 10.8 kton-year exposure of KamLAND collected from 2002 to 2019. This large exposure allows us to explore previously unconstrained parameter space for solar flare neutrinos. We found no statistical excess of neutrinos and established 90% confidence level upper limits of 8.4 × 107 cm-2 (3.0 × 109 cm-2) on the electron antineutrino (electron neutrino) fluence at 20 MeV normalized to the X12 flare, assuming that the neutrino fluence is proportional to the X-ray intensity.
Открытый доступ
Development of highly radiopure NaI(T1) scintillator for PICOLON dark matter search project
(2021) Fushimi, K.; Kanemitsu, Y.; Hirata, S.; Chernyak, D.; Kozlov, A.; Козлов, Александр Анатольевич
Highly radiopure NaI(T1) was developed to search for particle candidates of dark matter. Optimized methods were combined to reduce various radioactive impurities. K-40 was effectively reduced by the recrystallization method. The progenies of the decay chains of uranium and thorium were reduced by appropriate resins. The concentration of natural potassium in NaI(T1) crystal was reduced to 20 ppb. Concentrations of alpha-ray emitters were successfully reduced by appropriate resin selection. The present concentrations of the thorium series and Ra-226 were 1.2 +/- 1.4 mu Bq/kg and 13 +/- 4 mu Bq/kg, respectively. No significant excess in the concentration of Pb-210 was obtained, and the upper limit was 5.7 mu Bq/kg at 90% CL. The achieved level of radiopurity of NaI(T1) crystals makes the construction of a dark matter detector possible.
Открытый доступ
PICOLON dark matter search project by large-volume NaI(Tl) scintillator
(2024) Fushimi,K.; Chernyak, D.; Ejiri, H.; Hata, K.; Kozlov, A.; Козлов, Александр Анатольевич
Открытый доступ
Search for the Majorana Nature of Neutrinos in the Inverted Mass Ordering Region with KamLAND-Zen
(2023) Abe, S.; Asami, S.; Eizuka, M.; Futagi, S.; Kozlov, A.; Козлов, Александр Анатольевич