Персона: Мачулин, Игорь Николаевич
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Институт ядерной физики и технологий
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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Игорь Николаевич
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65 results
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- ПубликацияТолько метаданныеCalibration of the liquid argon ionization response to low energy electronic and nuclear recoils with DarkSide-50(2021) Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Grobov, A. V.; Machulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2021 American Physical Society. DarkSide-50 has demonstrated the high potential of dual-phase liquid argon time projection chambers in exploring interactions of WIMPs in the GeV/c2 mass range. The technique, based on the detection of the ionization signal amplified via electroluminescence in the gas phase, allows us to explore recoil energies down to the sub-keV range. We report here on the DarkSide-50 measurement of the ionization yield of electronic recoils down to ∼180 eVer, exploiting Ar37 and Ar39 decays, and extrapolated to a few ionization electrons with the Thomas-Imel box model. Moreover, we present a model-dependent determination of the ionization response to nuclear recoils down to ∼500 eVnr, the lowest ever achieved in liquid argon, using in situ neutron calibration sources and external datasets from neutron beam experiments.
- ПубликацияТолько метаданныеDirectionality measurement of CNO neutrinos with Borexino detector(2024) Basilico, D.; Bellini, G.; Biondi, R.; Benziger, J.; Litvinovich, E.; Machulin, I.; Skorokhvatov, M.; Литвинович, Евгений Александрович; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич
- ПубликацияТолько метаданныеPulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data(2021) Adhikari, P.; Ajaj, R.; Alpizar-Venegas, M.; Amaudruz, P. -A.; Grobov, A.; Ilyasov, A.; Levashko, N.; Machulin, I.; Ильясов, Айдар Иршатович; Мачулин, Игорь Николаевич© 2021, The Author(s).The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected.
- ПубликацияТолько метаданныеA study of events with photoelectric emission in the DarkSide-50 liquid argon Time Projection Chamber(2022) Agnes, P.; Albuquerque, I. F. M.; Alexander, T.; Alton, A. K.; Grobov, A.; Machulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2022 Elsevier B.V.Finding unequivocal evidence of dark matter interactions in a particle detector is a major goal of research in physics. Liquid argon time projection chambers offer a path to probe Weakly Interacting Massive Particles scattering cross sections on nuclei down to the so-called neutrino floor, in a mass range from a few GeV to hundreds of TeV. Based on the successful operation of the DarkSide-50 detector at LNGS, a new and more sensitive experiment, DarkSide-20k, has been designed and is now under construction. A thorough understanding of the DarkSide-50 detector response and, therefore, of all types of events observed in the detector, is essential for the optimal design of the new experiment. In this article, we report on a specific set of events, namely, standard two-pulse scintillation–ionization signals with a third small amplitude pulse, occurring within the 440μs data acquisition window of standard events. Some of these events are due to the photoionization of the TPC cathode. We compare our results with those published by collaborations using liquid xenon time projection chambers, which observed a similar phenomenon, and, in particular, with a recent paper by the LUX Collaboration (D.S. Akerib et al. Phys.Rev.D 102, 092004 (2020)) From the measured rate of these events, we estimate for the first time the quantum efficiency of the tetraphenyl butadiene deposited on the DarkSide-50 cathode at wavelengths of around 128 nm, in liquid argon. Also, both experiments observe events likely related to the photoionization of impurities in the liquid. The probability of photoelectron emission per unit length turns out to be an order of magnitude lower in DarkSide-50 than in LUX.
- ПубликацияТолько метаданныеUltra-low background physics: lessons from Borexino and future steps(2025) Zavatarelli, S.; Basilico, D.; Bellini, G.; Benziger, J.; Litvinovich, E.; Machulin, I.; Skorokhvatov, M.; Литвинович, Евгений Александрович; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич
- ПубликацияТолько метаданныеDesign and construction of a new detector to measure ultra-low radioactive-isotope contamination of argon(2020) Aalseth, C. E.; Abdelhakim, S.; Acerbi, F.; Agnes, P.; Grobov, A.; Ilyasov, A.; Levashko, N.; Machulin, I. N.; Skorokhvatov, M. D.; Ильясов, Айдар Иршатович; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич© 2020 IOP Publishing Ltd and Sissa MedialabLarge liquid argon detectors offer one of the best avenues for the detection of galactic weakly interacting massive particles (WIMPs) via their scattering on atomic nuclei. The liquid argon target allows exquisite discrimination between nuclear and electron recoil signals via pulse-shape discrimination of the scintillation signals. Atmospheric argon (AAr), however, has a naturally occurring radioactive isotope, 39Ar, a β emitter of cosmogenic origin. For large detectors, the atmospheric 39Ar activity poses pile-up concerns. The use of argon extracted from underground wells, deprived of 39Ar, is key to the physics potential of these experiments. The DarkSide-20k dark matter search experiment will operate a dual-phase time projection chamber with 50 tonnes of radio-pure underground argon (UAr), that was shown to be depleted of 39Ar with respect to AAr by a factor larger than 1400. Assessing the 39Ar content of the UAr during extraction is crucial for the success of DarkSide-20k, as well as for future experiments of the Global Argon Dark Matter Collaboration (GADMC). This will be carried out by the DArT in ArDM experiment, a small chamber made with extremely radio-pure materials that will be placed at the centre of the ArDM detector, in the Canfranc Underground Laboratory (LSC) in Spain. The ArDM LAr volume acts as an active veto for background radioactivity, mostly γ-rays from the ArDM detector materials and the surrounding rock. This article describes the DArT in ArDM project, including the chamber design and construction, and reviews the background required to achieve the expected performance of the detector.
- ПубликацияТолько метаданныеSearch for Dark Matter Particle Interactions with Electron Final States with DarkSide-50(2023) Agnes, P.; Albuquerque, IFM.; Alexander, T.; Alton, A. K.; Grobov, A.; Machulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил ДмитриевичWe present a search for dark matter particles with sub-GeV/c2 masses whose interactions have final state electrons using the DarkSide-50 experiment's (12 306 1 184) kg d low-radioactivity liquid argon exposure. By analyzing the ionization signals, we exclude new parameter space for the dark matter-electron cross section sigma over bar e, the axioelectric coupling constant gAe, and the dark photon kinetic mixing parameter kappa. We also set the first dark matter direct-detection constraints on the mixing angle IUe412 for keV/c2 sterile neutrinos.
- ПубликацияТолько метаданныеCorrelated and integrated directionality for sub-MeV solar neutrinos in Borexino(2022) Agostini, M.; Altenmuller, K.; Appel, S.; Atroshchenko, V.; Litvinovich, E.; Machulin, I.; Nugmanov, R.; Skorokhvatov, M.; Литвинович, Евгений Александрович; Мачулин, Игорь Николаевич; Скорохватов, Михаил ДмитриевичLiquid scintillator detectors play a central role in the detection of neutrinos from various sources. In particular, it is the only technique used so far for the precision spectroscopy of sub-MeV solar neutrinos, as demonstrated by the Borexino experiment at the Gran Sasso National Laboratory in Italy. The benefit of a high light yield, and thus a low energy threshold and a good energy resolution, comes at the cost of the directional information featured by water Cherenkov detectors, measuring B-8 solar neutrinos above a few MeV. In this paper we provide the first directionality measurement of sub-MeV solar neutrinos which exploits the correlation between the first few detected photons in each event and the known position of the Sun for each event. This is also the first signature of directionality in neutrinos elastically scattering off electrons in a liquid scintillator target. This measurement exploits the subdominant, fast Cherenkov light emission that precedes the dominant yet slower scintillation light signal. Through this measurement, we have also been able to extract the rate of Be-7 solar neutrinos in Borexino. The demonstration of directional sensitivity in a traditional liquid scintillator target paves the way for the possible exploitation of the Cherenkov light signal in future kton-scale experiments using liquid scintillator targets. Directionality is important for background suppression as well as the disentanglement of signals from various sources.
- ПубликацияТолько метаданныеConstraints on directionality effect of nuclear recoils in a liquid argon time projection chamber(2024) Agnes, P.; Albergo, S.; Albuquerque, I. F. M.; Alexander, T.; Grobov, A.; Machulin, I. N.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич
- ПубликацияТолько метаданныеFermionic sub-GeV dark matter from evaporating primordial black holes at DarkSide-50(2025) Agnes, P.; Albuquerque, I. F.; Alexander, T.; Grobov, A.; Machulin, I. N.; Nozdrina, A. O.; Skorokhvatov, M. D.; Мачулин, Игорь Николаевич; Скорохватов, Михаил Дмитриевич