Phase transition, radio- and photoluminescence of K3Lu(PO4)2 doped with Pr3+ ions

Luminescent characteristics of K3Lu(PO4)2:Pr3+ (1 and 5 mol.%) microcrystalline powders, a promising optical material for scintillation applications, were investigated using various experimental techniques. The material shows emission features connected with both high intensity interconfigurational 4f15d→4f2 transitions (broad UV emission bands) and intraconfigurational 4f2→4f2 transitions (weak emission lines in the visible range). The output of X-ray excited 4f15d→4f2 emission of Pr3+ increases with a temperature rise from 90 K to room tem- perature and higher depending on the Pr3+ ions concentration. The high 5% concentration of Pr3+ ions is found to be favourable for the stabilization of a monoclinic phase (P21/m space group) over a trigonal one (P3 space group) while emission properties of the material reveal that a phase transition occurs at higher temperatures. Decay kinetics of Pr3+ 4f15d→4f2 emission are recorded upon excitation with high repetition rate X-ray syn- chrotron excitation and pulse cathode ray excitation. Issues related to a non-exponential decay of luminescence and presence of slow decay components are discussed in terms of energy transfer dynamics. The presence of defects was revealed with thermoluminescence measurements and these are suggested to be the mainly responsible for delayed recombination of charge carriers on the Pr3+ 4f15d states. Some peculiarities of host-to- impurity energy transfer are discusse

Ultrafast hybrid nanocomposite scintillators: A review

In recent years, demand for scintillation detectors with high time resolution (better than 100 ps) has emerged in high-energy physics and medical imaging applications. In particular, time of flight positron emission tomography (TOF-PET) can greatly benefit from increasing time resolution of scintillators, which leads to the increase of signal-to-noise ratio, decrease of patient dose, and achievement of the superior spatial resolution of PET images. Currently, extensive research of various types of materials is carried out to achieve the best time resolution. In this review, the recent progress of various approaches is summarized and scintillation compounds with the best temporal characteristics are first reviewed. The review presents the physical processes causing fast luminescence in inorganic and organic materials. Special attention is paid to nanocomposites which belong to a new perspective class of scintillating materials, consisting of a plastic matrix, inorganic nanocrystalline fillers, and organic or inorganic luminescence activators and shifters. The main features and functions of all parts of existing and prospective nanocomposite scintillators are also discussed. A number of currently created and investigated nanocomposite materials with various compounds and structures are reviewed. © 2021 Elsevier B.V.Eesti Teadusagentuur, ETAg: PRG111, PRG629; European Regional Development Fund, ERDF: 2014-2020.4.01.15–0011, TK141Authors thank Minobrnauki project FEUZ-2020-0059 and Estonian Research Council (grants PRG629 and PRG111 ) for financial support. Authors are also grateful for partial support from the European Regional Development Fund (DoRA Pluss program) and the ERDF funding in Estonia granted to the Center of Excellence TK141 “ Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics ” (project No. 2014-2020.4.01.15–0011 )

ADAPTATION OF PRIMARY SCHOOL CHILDREN TO PHYSICAL CULTURE THROUGH OUTDOOR GAMES

Informational article about the influence of outdoor games on sports education of younger students and their introduction to physical culture. Conditions for effective adaptation to physical culture Mobile game as a means of adaptation of younger students the Main directions of adaptation.Информационная статья о влиянии подвижной игры на спортивное воспитание младших школьников и их приобщение к физической культуре. Условия эффективности адаптации к физической культуре Подвижная игра как средство адаптации младших школьников Основные направления адаптации

Effect of An Electron Beam Irradiation on Optical and Luminescence Properties of LiBaAlF6 Single Crystals

Paper reports the effect of a 10 keV, 110 keV and 10 MeV electron beam irradiation on optical and luminescence properties of LiBaAlF6 (LBAF) single crystals at 10, 90, and 293 K. Five absorption bands at 2.0, 3.2, 4.3, 4.9 and 5.5 eV were revealed in irradiated crystals in the energy range of 1.2–9.5 eV. Several PL emission bands (1.7–1.8, 2.2 and 2.5–3.5 eV) related to defects were found in the luminescence spectra at room temperature, while only one luminescence band at E = 2.2 eV appears at T = 90 K in LBAF crystals after a 10 MeV electron bombardment. The PL excitation spectra and time-response for these emission bands were studied at 10, 90, and 293 K. Thermoluminescence (TL) of irradiated crystals was studied in the temperature range of 90–740 K. New TL glow peaks at 166, 530 and 670 K were revealed and their parameters were determined. Temperature dependence of relative photoluminescence yield recorded monitoring emission at the 1.87 and 2.23 eV in the temperature range from 130 to 450 K, were fitted using five quenching processes related to TL glow peaks revealed in our research. Significant similarity in the manifestation of radiation-induced defects for LBAF and previously studied LiBaF3 single crystals is noted. The effect of an electron beam irradiation on optical and luminescence properties of LBAF single crystals and possible origin of the radiation defects were discussed. © 2017 Elsevier B.V.This work was partially supported by the Ministry of Education and Science of the Russian Federation (Contract No.02.A03.21.0006) (the basic part of the government mandate), the Center of Excellence "Radiation and Nuclear Technologies" (Competitiveness Enhancement Program of Ural Federal University, Russia), HASYLAB DESY (Project No.20110843), Estonian Research Council (projects IUT2-26 and PUT1081). We are grateful to Ludmila Isaenko for providing the crystals examined and Eugene Vasilchenko for recording a high-temperature TL glow curve

Phase Transition, Radio- and Photoluminescence of K3Lu(PO4)2 Doped with Pr3+ Ions

Luminescent characteristics of K3Lu(PO4)2:Pr3+ (1 and 5 mol.%) microcrystalline powders, a promising optical material for scintillation applications, were investigated using various experimental techniques. The material shows emission features connected with both high intensity interconfigurational 4f15d→4f2 transitions (broad UV emission bands) and intraconfigurational 4f2→4f2 transitions (weak emission lines in the visible range). The output of X-ray excited 4f15d→4f2 emission of Pr3+ increases with a temperature rise from 90 K to room temperature and higher depending on the Pr3+ ions concentration. The high 5% concentration of Pr3+ ions is found to be favourable for the stabilization of a monoclinic phase (P21/m space group) over a trigonal one (P3‾ space group) while emission properties of the material reveal that a phase transition occurs at higher temperatures. Decay kinetics of Pr3+ 4f15d→4f2 emission are recorded upon excitation with high repetition rate X-ray synchrotron excitation and pulse cathode ray excitation. Issues related to a non-exponential decay of luminescence and presence of slow decay components are discussed in terms of energy transfer dynamics. The presence of defects was revealed with thermoluminescence measurements and these are suggested to be the mainly responsible for delayed recombination of charge carriers on the Pr3+ 4f15d states. Some peculiarities of host-to-impurity energy transfer are discussed. © 2020 Elsevier B.V.The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060), Act 211 Government of the Russian Federation (contract № 02.A03.21.0006), STSM grant from COST Action TD1401 ″FAST” as well as by Estonian Research Council (project PRG629) and Estonian Center of Excellence in Research “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” TK141 (project No. 2014-2020.4.01.15-0011) by the ERDF funding in Estonia. The time-resolved X-ray excited measurements were performed at the Shared research center SSTRC based on the NovoFEL/VEPP-4 - VEPP-2000 facilities at Budker Institute of Nuclear Physics (Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia) while using experimental equipment funded by RFMEFI62119X0022 project. Authors thank Erica Viviani (University of Verona) for assistance in the synthesis of the samples and Yulya Khatchenko (UrFU, Ekaterinburg) for assistance in the processing the experimental data. F. P. and M. B. thank the Facility “Centro Piattaforme Tecnologiche” of the University of Verona for access to the Thermo ARL X’TRA powder diffractometer

Progress in development of a new luminescence setup at the FinEstBeAMS beamline of the MAX IV laboratory

The main funding for the FinEstBeAMS beamline has been obtained from the European Union through the European Regional Development Fund (project “Estonian beamline to MAX-IV synchrotron”, granted to the University of Tartu) and from the Academy of Finland through the Finnish Research Infrastructure funding projects ( FIRI2010 , FIRI2013 , FIRI2014 ). The authors also acknowledge the funding contributions of the University of Oulu , University of Turku , Tampere University of Technology , the Estonian Research Council ( IUT 2-25 , IUT 2-26 , PRG-111 ), as well as the Estonian Centre of Excellence in Research “Advanced materials and high-technology devices for sustainable energetics, sensorics and nanoelectronics” TK141 (2014-2020.4.01.15-0011). The strategic funding of Finnish FIMAX consortium coordinating university , University of Oulu , for beamline personnel is also acknowledged. The authors thank the MAX IV Laboratory for financial and infrastructural support as well as for assistance during the construction of the FinEstBeaMS beamline.FinEstBeAMS is a new materials science beamline at the 1.5 GeV storage ring of the MAX IV Laboratory in Lund, Sweden. It has been built based on grazing incidence monochromatization of synchrotron light, which allows to cover a remarkably wide excitation energy range from ultraviolet to soft x-rays (4.5–1450 eV). A new mobile luminescence spectroscopy end station has been commissioned with design benefitting from the advantages of a high flux elliptically polarizing undulator light source. We report on the design of the luminescence end station, its technical realization and performance achieved so far. Special attention is paid to the experimental challenges for luminescence spectroscopy under grazing incidence excitation conditions. The first luminescence results obtained demonstrate a reliable performance of the advanced setup at FinEstBeAMS.Eesti Teadusagentuur IUT 2-25,PRG-111,IUT 2-26; European Commission; University of Tartu; Academy of Finland FIRI2010,FIRI2013,FIRI2014; Tampereen Teknillinen Yliopisto; Turun Yliopisto; European Regional Development Fund; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Action recognition using single-pixel time-of-flight detection

Action recognition is a challenging task that plays an important role in many robotic systems, which highly depend on visual input feeds. However, due to privacy concerns, it is important to find a method which can recognise actions without using visual feed. In this paper, we propose a concept for detecting actions while preserving the test subject's privacy. Our proposed method relies only on recording the temporal evolution of light pulses scattered back from the scene. Such data trace to record one action contains a sequence of one-dimensional arrays of voltage values acquired by a single-pixel detector at 1 GHz repetition rate. Information about both the distance to the object and its shape are embedded in the traces. We apply machine learning in the form of recurrent neural networks for data analysis and demonstrate successful action recognition. The experimental results show that our proposed method could achieve on average 96.47 % accuracy on the actions walking forward, walking backwards, sitting down, standing up and waving hand, using recurrent neural network

Time-Resolved Luminescence Spectroscopy of Pure and Doped with Ce3+ ions SrAlF5 Crystals

The results of a study of time-resolved photoluminescence (PL) and energy transfer in both pure and doped with Ce3+ ions SrAlF5 (SAF) single crystals are presented. The time-resolved and steady-state PL spectra in the energy range of 1.5-6.0 eV, the PL excitation spectra and the reflectivity in the energy range of 3.7-21 eV, as well as the PL decay kinetics were measured at 8.8 and 295 K. The lattice defects were revealed in the low temperature PL spectra (emission bands at 2.9 and 4.5 eV) in the undoped SAF crystals. The luminescence spectra of the doped Ce3+:SAF crystals demonstrate a new selective emission bands in the range of 3.7-4.5 eV with the exponential decay kinetics (τ ≈ 60 ns at X-ray excitation). These bands correspond to the d-f transitions in Ce3+ ions, which occupy nonequivalent sites in the crystal lattice. © 2010 Pleiades Publishing, Ltd.This work was supported by the RFBR (grants Nos. 07-02-00442; 07-02-12015; 09-02-00493)