Cosmic Ray Extremely Distributed Observatory: a global network of detectors to probe contemporary physics mysteries

In the past few years, cosmic-rays beyond the GZK cut-off ($E > 5 \times 10^{19}$ eV) have been detected by leading collaborations such as Pierre Auger Observatory. Such observations raise many questions as to how such energies can be reached and what source can possibly produce them. Although at lower energies, mechanisms such as Fermi acceleration in supernovae front shocks seem to be favored, top-down scenarios have been proposed to explain the existence of ultra-high energy cosmic-rays: the decay of super-massive long-lived particles produced in the early Universe may yield to a flux of ultra-high energy photons. Such photons might be presently generating so called super-preshowers, an extended cosmic-ray shower with a spatial distribution that can be as wide as the Earth diameter. The Cosmic Ray Extremely Distributed Observatory (CREDO) mission is to find such events by means of a network of detectors spread around the globe. CREDO's strategy is to connect existing detectors and create a worldwide network of cosmic-ray observatories. Moreover, citizen-science constitutes an important pillar of our approach. By helping our algorithms to recognize detection patterns and by using smartphones as individual cosmic-ray detectors, non-scientists can participate in scientific discoveries and help unravel some of the deepest mysteries in physics.Comment: excited QCD Conference, CREDO Collaboration, 7 pages, 3 figure

Nieniszczące badania betonów wysokowartościowych w kontekście ich zastosowania w budownictwie podziemnym

Due to the possibility of using high performance concrete in the underground construction industry, e.g. for casing of tunnels and wells, the authors of this article have undertaken an attempt to check whether existing standards and instructions allow for assessing the strength of high performance concrete during its curing with non-invasive methods. This paper presents the results of non-invasive tests performed on high performance concrete samples in various curing periods (3, 7, 14, 21 and 28 days). On the basis of the results obtained, the compressive strength of the samples was estimated using base curves from the literature. The existing base curves were also scaled according to the recommendations contained in the standards and sectoral instructions. In order to be able to carry out a full analysis of test results, also authors' base curves were set. As a result, comparative material was obtained, which allows for assessing the possibility of applying the aforementioned methods for the tested high performance concrete in the time function.Ze względu na możliwość wykorzystania betonu wysokowartościowego w budownictwie podziemnym np. na obudowę tuneli i szybów, autorzy artykułu podjęli próbę sprawdzenia, czy istniejące normy i instrukcje umożliwiają ocenę wytrzymałości betonu wysokowartościowego w czasie jego dojrzewania metodami nieniszczącymi. W pracy przedstawiono wyniki przeprowadzonych badań nieniszczących wykonanych na próbkach z betonu wysokowartościowego w różnych okresach dojrzewania (3, 7, 14, 21 i 28 dniach). Na podstawie uzyskanych wyników badań dokonano szacowania wytrzymałości na ściskanie badanych próbek bazując na literaturowych krzywych bazowych. Dokonano także skalowania istniejących krzywych bazowych zgodnie z zaleceniami norm i instrukcji branżowych. Aby móc dokonać pełnej analizy wyników badań wyznaczono także autorskie krzywe bazowe. W rezultacie otrzymano materiał porównawczy, pozwalający na ocenę możliwości stosowania wyżej wymienionych metod dla badanego betonu wysokowartościowego w funkcji czasu