The current status of orbital experiments for UHECR studies

Two types of orbital detectors of extreme energy cosmic rays are being developed nowadays: (i) TUS and KLYPVE with reflecting optical systems (mirrors) and (ii) JEM-EUSO with high-transmittance Fresnel lenses. They will cover much larger areas than existing ground-based arrays and almost uniformly monitor the celestial sphere. The TUS detector is the pioneering mission developed in SINP MSU in cooperation with several Russian and foreign institutions. It has relatively small field of view (+/-4.5 deg), which corresponds to a ground area of 6.4x10^3 sq.km. The telescope consists of a Fresnel-type mirror-concentrator (~2 sq.m) and a photo receiver (a matrix of 16x16 photomultiplier tubes). It is to be deployed on the Lomonosov satellite, and is currently at the final stage of preflight tests. Recently, SINP MSU began the KLYPVE project to be installed on board of the Russian segment of the ISS. The optical system of this detector contains a larger primary mirror (10 sq.m), which allows decreasing the energy threshold. The total effective field of view will be at least +/-14 degrees to exceed the annual exposure of the existing ground-based experiments. Several configurations of the detector are being currently considered. Finally, JEM-EUSO is a wide field of view (+/-30 deg) detector. The optics is composed of two curved double-sided Fresnel lenses with 2.65 m external diameter, a precision diffractive middle lens and a pupil. The ultraviolet photons are focused onto the focal surface, which consists of nearly 5000 multi-anode photomultipliers. It is developed by a large international collaboration. All three orbital detectors have multi-purpose character due to continuous monitoring of various atmospheric phenomena. The present status of development of the TUS and KLYPVE missions is reported, and a brief comparison of the projects with JEM-EUSO is given.Comment: 18 pages; based on the rapporteur talk given by M.I. Panasyuk at ECRS-2014; v2: a few minor language issues fixed thanks to the editor; to be published in the proceeding

An extensive-air-shower-like event registered with the TUS orbital detector

TUS (Tracking Ultraviolet Set-up) is the world's first orbital detector of ultra-high-energy cosmic rays (UHECRs). It was launched into orbit on 28th April 2016 as a part of the scientific payload of the Lomonosov satellite. The main aim of the mission was to test the technique of measuring the ultraviolet fluorescence and Cherenkov radiation of extensive air showers generated by primary cosmic rays with energies above ~100 EeV in the Earth atmosphere from space. During its operation for 1.5 years, TUS registered almost 80,000 events with a few of them satisfying conditions anticipated for extensive air showers (EASs) initiated by UHECRs. Here we discuss an event registered on 3rd October 2016. The event was measured in perfect observation conditions as an ultraviolet track in the nocturnal atmosphere of the Earth, with the kinematics and the light curve similar to those expected from an EAS. A reconstruction of parameters of a primary particle gave the zenith angle around 44$^\circ$ but an extreme energy not compatible with the cosmic ray energy spectrum obtained with ground-based experiments. We discuss in details all conditions of registering the event, explain the reconstruction procedure and its limitations and comment on possible sources of the signal, both of anthropogenic and astrophysical origin. We believe this detection represents a significant milestone in the space-based observation of UHECRs because it proves the capability of an orbital telescope to detect light signals with the apparent motion and light shape similar to what are expected from EASs. This is important for the on-going development of the future missions KLYPVE-EUSO and POEMMA, aimed for studying UHECRs from space.Comment: 24 pages; v2: important changes to address comments by the anonymous referee; main conclusions unchange

ИЗУЧЕНИЕ СВОЙСТВ ТОНКОДИСПЕРСНЫХ ЧАСТИЦ, ПОЛУЧЕННЫХ ПРИ ДИСПЕРГИРОВАНИИ ТВЕРДОГО СПЛАВА ВК6 ЭЛЕКТРОИМПУЛЬСНЫМ МЕТОДОМ

 Properties of WC–6Co hard alloy powders obtained by the method of spark plasma dispersion (SPD) are presemed. Powders of WC–6Co hard alloy were produced using spark erosion in distilled water. The properties of powders, such as specific surface area, morphology, structure and size distribution, were studied. Investigation of the powder properties was made using the methods of scanning electron microscopy, X-ray phase analysis and disk centrifugal sedimentation particle size analysis. The principal possibility of SPD method to produce highly active additives, suitable to use during creation of tools and hardening of wear-resistant coatings from hard alloy waste is shown. В работе представлены результаты электроискрового диспергирования (ЭИД) стружки из сплава ВК6 в воде. Приведены величины удельной поверхности, морфологии, структуры и распределения частиц в порошках по размерам. Для исследования свойств использовали дисковый центробежный седиментационный анализатор размера частиц, методы растровой электронной микроскопии и рентгенофазового анализа. Показана принципиальная возможность применения ЭИД для изготовления тонкодисперсных порошков из отходов твердого сплава, пригодных для повторного использования в качестве высокоактивных добавок при создании инструмента и получении износостойких упрочняющих покрытий.

Обеспечение радиационной безопасности населения восточных районов Оренбургской области при использовании питьевой воды из подземных источников водоснабжения

Starting from 2014, several cases of exceedance of the specific total alpha-activity of the natural radionuclides and specific activity of 222Rn were identified in the water of the underground wells in the eastern districts of the Orenburg region. Based on the results of the surveys, a number of settlements were equipped with the systems of aeration of water from underground wells prior to the distribution, but significant expenditures on the technical maintenance of the aeration units lead to their frequent malfunctions. Based on the results of the surveys of the drinking water in settlements of the Adamovskiy, Kvarkenskiy, Novoorkskiy, Dombarovsky, Svetlinsky districts and Yasnenskiy urban district, it was estimated that in some settlements specific activity of 222Rn in drinking water exceeded the intervention levels up to a factor of 10. No exceedances of intervention levels for 226Ra, 224Ra, 228Ra, 210Pb, 210Po and 238U were identified. Based on the results of experiments and analyses the authors performed the hygienic assessment of the indicators of the radiation safety of the drinking water from the underground water supply sources in several settlements in the eastern districts of the Orenburg region, performed the analysis of the effectiveness of the aeration systems, developed recommendations on the provision of the radiation safety of the public of the eastern parts of the Orenburg region for the use of the drinking water from the underground water supply sources and developed proposals on the improvement of the limitation of concentration of 222Ra in drinking water.Начиная с 2014 г., в воде подземных источников восточных районов Оренбургской области стали фиксироваться случаи превышения удельной суммарной альфа-активности природных радионуклидов и удельной активности 222Rn. По результатам исследований в ряде населенных пунктов были установлены системы аэрации воды подземных источников перед подачей ее в распределительную сеть, но значительные затраты на техническое обслуживание аэрационных установок привели к перебоям в их функционировании. На основании выполненных исследований питьевой воды в населенных пунктах Адамовского, Кваркенского, Новоорского, Домбаровского, Светлинского районов и Ясненского городского округа было установлено, что в отдельных населенных пунктах удельная активность 222Rn в питьевой воде более чем в 10 раз превышала уровень вмешательства; превышений уровней вмешательства по содержанию в воде 226Ra, 224Ra, 228Ra, 210Pb, 210Po и 238U не было выявлено. По результатам проведенных экспериментов и анализов представлена гигиеническая оценка показателей радиационной безопасности питьевой воды подземных источников водоснабжения ряда населенных пунктов восточных районов Оренбургской области, проведен анализ эффективности работы систем аэрации, разработаны рекомендации по обеспечению радиационной безопасности населения Восточного Оренбуржья при потреблении воды подземных источников, а также представлены предложения по усовершенствованию нормирования содержания 222Rn в питьевой воде

Prospects in Analytical Atomic Spectrometry

Tendencies in five main branches of atomic spectrometry (absorption, emission, mass, fluorescence and ionization spectrometry) are considered. The first three techniques are the most widespread and universal, with the best sensitivity attributed to atomic mass spectrometry. In the direct elemental analysis of solid samples, the leading roles are now conquered by laser-induced breakdown and laser ablation mass spectrometry, and the related techniques with transfer of the laser ablation products into inductively-coupled plasma. Advances in design of diode lasers and optical parametric oscillators promote developments in fluorescence and ionization spectrometry and also in absorption techniques where uses of optical cavities for increased effective absorption pathlength are expected to expand. Prospects for analytical instrumentation are seen in higher productivity, portability, miniaturization, incorporation of advanced software, automated sample preparation and transition to the multifunctional modular architecture. Steady progress and growth in applications of plasma- and laser-based methods are observed. An interest towards the absolute (standardless) analysis has revived, particularly in the emission spectrometry.Comment: Proofread copy with an added full reference list of 279 citations. A pdf version of the final published review may be requested from Alexander Bol'shakov <[email protected]

Neutrino Target-of-Opportunity Observations with Space-based and Suborbital Optical Cherenkov Detectors

Cosmic-ray accelerators capable of reaching ultra-high energies are expected to also produce very-high energy neutrinos via hadronic interactions within the source or its surrounding environment. Many of the candidate astrophysical source classes are either transient in nature or exhibit flaring activity. Using the Earth as a neutrino converter, suborbital and space-based optical Cherenkov detectors, such as EUSO-SPB2 and POEMMA, will be able to detect upward-moving extensive air showers induced by decay tau-leptons generated from cosmic tau neutrinos with energies ∼10 PeV and above. Both EUSO-SPB2 and POEMMA will be able to quickly repoint, enabling rapid response to astrophysical transient events. we calculate the transient sensitivity and sky coverage for both EUSO-SPB2 and POEMMA, accounting for constraints imposed by the Sun and the Moon on the observation time. We also calculate both detectors\u27 neutrino horizons for a variety of modeled astrophysical neutrino fluences. We find that both EUSO-SPB2 and POEMMA will achieve transient sensitivities at the level of modeled neutrino fluences for nearby sources. We conclude with a discussion of the prospects of each mission detecting at least one transient event for various modeled astrophysical neutrino sources

Neutrino Target-of-Opportunity Observations with Space-based and Suborbital Optical Cherenkov Detectors

Cosmic-ray accelerators capable of reaching ultra-high energies are expected to also produce very-high energy neutrinos via hadronic interactions within the source or its surrounding environment. Many of the candidate astrophysical source classes are either transient in nature or exhibit flaring activity. Using the Earth as a neutrino converter, suborbital and space-based optical Cherenkov detectors, such as POEMMA and EUSO-SPB2, will be able to detect upward-moving extensive air showers induced by decaying tau-leptons generated from cosmic tau neutrinos with energies ∼10 PeV and above. Both EUSO-SPB2 and POEMMA will be able to quickly repoint, enabling rapid response to astrophysical transient events. We calculate the transient sensitivity and sky coverage for both EUSO-SPB2 and POEMMA, accounting for constraints imposed by the Sun and the Moon on the observation time. We also calculate both detectors\u27 neutrino horizons for a variety of modeled astrophysical neutrino fluences. We find that both EUSO-SPB2 and POEMMA will achieve transient sensitivities at the level of modeled neutrino fluences for nearby sources. We conclude with a discussion of the prospects of each mission detecting at least one transient event for various modeled astrophysical neutrino sources