Potential for measuring the longitudinal and lateral profile of muons in TeV air showers with IACTs

Muons are copiously produced within hadronic extensive air showers (EAS) occurring in the Earth's atmosphere, and are used by particle air shower detectors as a means of identifying the primary cosmic ray which initiated the EAS. Imaging Atmospheric Cherenkov Telescopes (IACTs), designed for the detection of gamma-ray initiated EAS for the purposes of Very High Energy (VHE) gamma-ray astronomy, are subject to a considerable background signal due to hadronic EAS. Although hadronic EAS are typically rejected for gamma-ray analysis purposes, single muons produced within such showers generate clearly identifiable signals in IACTs and muon images are routinely retained and used for calibration purposes. For IACT arrays operating with a stereoscopic trigger, when a muon triggers one telescope, other telescopes in IACT arrays usually detect the associated hadronic EAS. We demonstrate for the first time the potential of IACT arrays for competitive measurements of the muon content of air showers, their lateral distribution and longitudinal profile of production slant heights in the TeV energy range. Such information can provide useful input to hadronic interaction models.Comment: 15 pages, 11 figures, 2 tables, accepted for publication in Astroparticle Physic

Clean and efficient extraction of copper ions and deposition as metal

AbstractA simple, clean and efficient one-pot process is offered as an alternative to the conventional complex processing presently used to extract copper ions from copper containing materials, like copper concentrate or slag, and to form copper metal. The alternative process uses a eutectic molten salt of potassium chloride, sodium chloride and zinc chloride as the reaction fluid which is recyclable, low in cost, environmentally benign, low melting (melting point 204°), high boiling (vapor pressure is only a few psi at 800°) and chemically, thermally and physically stable. The metal completely dissolves out of copper concentrate or slag in the aerobic eutectic molten chloride salt in a graphite or glassy carbon pot, which serves as a cathode, with a graphite anode, to reduce the metal ions to metal which sinks to the bottom of the graphite pot. The total efficiency for extraction and deposition is virtually 100% as determined by elemental and gravimetric analyses

Report on Tests and Measurements of Hadronic Interaction Properties with Air Showers

We present a summary of recent tests and measurements of hadronic interaction properties with air showers. This report has a special focus on muon density measurements. Several experiments reported deviations between simulated and recorded muon densities in extensive air showers, while others reported no discrepancies. We combine data from eight leading air shower experiments to cover shower energies from PeV to tens of EeV. Data are combined using the z-scale, a unified reference scale based on simulated air showers. Energy-scales of experiments are cross-calibrated. Above 10 PeV, we find a muon deficit in simulated air showers for each of the six considered hadronic interaction models. The deficit is increasing with shower energy. For the models EPOS-LHC and QGSJet-II.04, the slope is found significant at 8 sigma.Comment: Submitted to the Proceedings of UHECR201

Magnetic transitions in Pr2NiO4 single crystal

The magnetic properties of a stoichiometric Pr2NiO4 single crystal have been examined by means of the temperature dependence of the complex ac susceptibility and the isothermal magnetization in fields up to 200 kOe at T=4.2 K. Three separate phases have been identified and their anisotropic character has been analyzed. A collinear antiferromagnetic phase appears first between TN = 325 K and Tc1 = 115 K, where the Pr ions are polarized by an internal magnetic field. At Tc1 a first modification of the magnetic structure occurs in parallel with a structural phase transition (Bmab to P42/ncm). This magnetic transition has a first‐order character and involves both the out‐of‐plane and the in‐plane spin components (magnetic modes gx and gxcyfz, respectively). A second magnetic transition having also a first‐order character is also clearly identified at Tc2 = 90 K which corresponds to a spin reorientation process (gxcyfz to cxgyaz magnetic modes). It should be noted as well that the out‐of‐phase component of χac shows a peak around 30 K which reflects the coexistence of both magnetic configurations in a wide temperature interval. Finally, two field‐induced transitions have been observed at 4.2 K when the field is directed along the c axis. We propose that the high‐field anomaly arises from a metamagnetic transition of the weak ferromagnetic component, similarly to La2CuO4

Use of coculture and carbon source manipulation to stimulate antibiotic production in soil-dwelling microbes

This study aimed to discover new antibiotics produced by soil microbes. Previous studies have shown that manipulation of microbial growth conditions through variable carbon sources and growth in coculture could induce the production of novel antibiotics by soil microbes. This study expanded on these observations by testing the levels of antibiotic production when a producing strain was grown in twenty different carbon sources and cocultured with more than one hundred different coculture partners. Organic extracts from liquid cultures were tested against a panel of four safe relatives to ESKAPE pathogens and one yeast to detect antimicrobial activity. Certain combinations of carbon sources and stimulating strains were better able to induce antimicrobial activity from the selected producers than other combinations. Flaxseed meal was the most effective carbon source for the strains tested, and Gram-negative bacteria seemed to stimulate the most activity. These results serve as proof-of-concept that these techniques are an effective mechanism for manipulating the production of antibiotics from soil microbes

Quantum chaos in the atomic gravitational cavity

We report quantum chaos phenomena in the atomic gravitational cavity. We consider the reflection of cold atoms from a temporally modulated evanescent wave. In the globally chaotic regime, for small modulation, the squared energy distribution as a function of time demonstrates dynamical localization. However, for larger modulation delocalization occurs

Efficient propagation of systematic uncertainties from calibration to analysis with the SnowStorm method in IceCube

Efficient treatment of systematic uncertainties that depend on a large number of nuisance parameters is a persistent difficulty in particle physics and astrophysics experiments. Where low-level effects are not amenable to simple parameterization or re-weighting, analyses often rely on discrete simulation sets to quantify the effects of nuisance parameters on key analysis observables. Such methods may become computationally untenable for analyses requiring high statistics Monte Carlo with a large number of nuisance degrees of freedom, especially in cases where these degrees of freedom parameterize the shape of a continuous distribution. In this paper we present a method for treating systematic uncertainties in a computationally efficient and comprehensive manner using a single simulation set with multiple and continuously varied nuisance parameters. This method is demonstrated for the case of the depth-dependent effective dust distribution within the IceCube Neutrino Telescope

NA61/SHINE facility at the CERN SPS: beams and detector system

NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose experimental facility to study hadron production in hadron-proton, hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton Synchrotron. It recorded the first physics data with hadron beams in 2009 and with ion beams (secondary 7Be beams) in 2011. NA61/SHINE has greatly profited from the long development of the CERN proton and ion sources and the accelerator chain as well as the H2 beamline of the CERN North Area. The latter has recently been modified to also serve as a fragment separator as needed to produce the Be beams for NA61/SHINE. Numerous components of the NA61/SHINE set-up were inherited from its predecessors, in particular, the last one, the NA49 experiment. Important new detectors and upgrades of the legacy equipment were introduced by the NA61/SHINE Collaboration. This paper describes the state of the NA61/SHINE facility - the beams and the detector system - before the CERN Long Shutdown I, which started in March 2013