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Abdellaoui, G.,Abe, S.,Adams Jr., J.H.,Ahriche Jr., A.,Allard Jr., D.,Allen Jr., L.,Alonso Jr., G.,Anchordoqui Jr., L.,Anzalone Jr., A.,Arai Jr., Y.,Asano Jr., K.,Attallah Jr., R.,Attoui Jr., H.,Ave P North-Holland 2019 Astroparticle physics Vol.111 No.-
<P><B>Abstract</B></P> <P>The JEM-EUSO (Joint Experiment Missions for the Extreme Universe Space Observatory) program aims at developing Ultra-Violet (UV) fluorescence telescopes for efficient detections of Extensive Air Showers (EASs) induced by Ultra-High Energy Cosmic Rays (UHECRs) from satellite orbit. In order to demonstrate key technologies for JEM-EUSO, we constructed the EUSO-Balloon instrument that consists of a ∼1 m<SUP>2</SUP> refractive telescope with two Fresnel lenses and an array of multi-anode photo-multiplier tubes at the focus. Distinguishing it from the former balloon-borne experiments, EUSO-Balloon has the capabilities of single photon counting with a gate time of 2.3 µs and of imaging with a total of 2304 pixels. As a pathfinder mission, the instrument was launched for an 8 h stratospheric flight on a moonless night in August 2014 over Timmins, Canada. In this work, we analyze the count rates over ∼2.5 h intervals. The measurements are of diffuse light, e.g. of airglow emission, back-scattered from the Earth’s atmosphere as well as artificial light sources. Count rates from such diffuse light are a background for EAS detections in future missions and relevant factor for the analysis of EAS events. We also obtain the geographical distribution of the count rates over a ∼780 km<SUP>2</SUP> area along the balloon trajectory. In developed areas, light sources such as the airport, mines, and factories are clearly identified. This demonstrates the correct location of signals that will be required for the EAS analysis in future missions. Although a precise determination of count rates is relevant for the existing instruments, the absolute intensity of diffuse light is deduced for the limited conditions by assuming spectra models and considering simulations of the instrument response. Based on the study of diffuse light by EUSO-Balloon, we also discuss the implications for coming pathfinders and future space-based UHECR observation missions.</P>
EUSO-TA – First results from a ground-based EUSO telescope
Abdellaoui, G.,Abe, S.,Adams Jr., J.H.,Ahriche Jr., A.,Allard Jr., D.,Allen Jr., L.,Alonso Jr., G.,Anchordoqui Jr., L.,Anzalone Jr., A.,Arai Jr., Y.,Asano Jr., K.,Attallah Jr., R.,Attoui Jr., H.,Ave P Elsevier 2018 Astroparticle physics Vol.102 No.-
<P>EUSO-TA is a ground-based telescope, installed at the Telescope Array (TA) site in Black Rock Mesa, Utah, USA. This is the first detector to successfully use a Fresnel lens based optical system and multi-anode photomultipliers (64 channels per tube, 2304 channels encompassing a 10.6 degrees x 10.6 degrees field of view) for detection of Ultra High Energy Cosmic Rays (UHECR). The telescope is located in front of one of the fluorescence detectors of the TA experiment. Since its installation in 2013, the detector has observed several ultra-high energy cosmic ray events and, in addition, meteors. The limiting magnitude of 5.5 on summed frames (similar to 3 ms) has been established. Measurements of the UV night sky emission in different conditions and moon phases and positions have been completed. The performed observations serve as a proof of concept for the future application of this detector technology. (C) 2018 Elsevier B.V. All rights reserved.</P>
Cosmic ray oriented performance studies for the JEM-EUSO first level trigger
Abdellaoui, G.,Abe, S.,Acheli, A.,Adams Jr., J.H.,Ahmad Jr., S.,Ahriche Jr., A.,Albert Jr., J.-N.,Allard Jr., D.,Alonso Jr., G.,Anchordoqui Jr., L.,Andreev Jr., V.,Anzalone Jr., A.,Aouimeur Jr., W.,Ar Elsevier BV * North-Holland 2017 Nuclear Instruments & Methods in Physics Research. Vol. No.
<P><B>Abstract</B></P> <P>JEM-EUSO is a space mission designed to investigate Ultra-High Energy Cosmic Rays and Neutrinos ( E > 5 ⋅ 1 <SUP> 0 19 </SUP> eV ) from the International Space Station (ISS). Looking down from above its wide angle telescope is able to observe their air showers and collect such data from a very wide area. Highly specific trigger algorithms are needed to drastically reduce the data load in the presence of both atmospheric and human activity related background light, yet retain the rare cosmic ray events recorded in the telescope. We report the performance in offline testing of the first level trigger algorithm on data from JEM-EUSO prototypes and laboratory measurements observing different light sources: data taken during a high altitude balloon flight over Canada, laser pulses observed from the ground traversing the real atmosphere, and model landscapes reproducing realistic aspect ratios and light conditions as would be seen from the ISS itself. The first level trigger logic successfully kept the trigger rate within the permissible bounds when challenged with artificially produced as well as naturally encountered night sky background fluctuations and while retaining events with general air-shower characteristics.</P>
Choi, M.J.,Park, H.K.,Yun, G.S.,Lee, W.,Luhmann Jr., N.C.,Lee, K.D.,Ko, W.-H.,Park, Y.-S.,Park, B.H.,In, Y. IOP 2016 Nuclear fusion Vol.56 No.6
<P>Minor and major disruptions by explosive MHD instabilities were observed with the novel quasi 3D electron cyclotron emission imaging (ECEI) system in the KSTAR plasma. The fine electron temperature (<I>T</I> <SUB>e</SUB>) fluctuation images revealed two types of minor disruptions: a small minor disruption is a <img ALIGN='MIDDLE' ALT='$q\sim 2$ ' SRC='http://ej.iop.org/images/0029-5515/56/6/066013/nfaa223aieqn001.gif'/> localized fast transport event due to a single <I>m</I>/<I>n</I> = 2/1 magnetic island growth, while a large minor disruption is partial collapse of the <img ALIGN='MIDDLE' ALT='$q\leqslant 2$ ' SRC='http://ej.iop.org/images/0029-5515/56/6/066013/nfaa223aieqn002.gif'/> region with two successive fast heat transport events by the correlated <I>m</I>/<I>n</I> = 2/1 and <I>m</I>/<I>n</I> = 1/1 instabilities. The <I>m</I>/<I>n</I> = 2/1 magnetic island growth during the minor disruption is normally limited below the saturation width. However, as the additional interchange-like perturbation grows near the inner separatrix of the 2/1 island, the 2/1 island can expand beyond the limit through coupling with the cold bubble formed by the interchange-like perturbation.</P>
Ahmad, D,Choi, W J,Seo, Y I,Jung, S-G,Kim, Y C,Salem-Sugui Jr, S,Park, T,Kwon, Y S IOP Publishing Ltd 2017 Superconductor science & technology Vol.30 No.10
<P>We investigate the doping dependence of flux pinning in superconducting NaFe<img ALIGN='MIDDLE' ALT='${}_{1-x}$' SRC='http://ej.iop.org/images/0953-2048/30/10/105006/sustaa7ec3ieqn3.gif'/>Co<SUB> <I>x</I> </SUB>As (<I>x</I> = 0.01, 0.03, 0.05 and 0.07) single crystals grown by the Bridgman method. The electronic specific heat displays a pronounced anomaly in a sample series at superconducting transition temperature, which hardly shows any residual part at low temperature. We found that Co doping plays an important role in signifying the secondary peak in the magnetic hysteresis of optimally doped (<I>x</I> = 0.03) and heavily doped (<I>x</I> = 0.05, 0.07) crystals. Furthermore, the dependence of the relaxation rate <I>S</I> = ∣d ln <I>M</I>/d ln <I>t</I>∣ on magnetic field and temperature exhibits a decreasing trend within a certain range corresponding to the secondary peak effect in the optimally and heavily doped samples. The magnetic relaxation rate combined with the Maley analysis of the current-dependent creep energy shows a single-vortex pinning in the lightly doped sample dominant at low applied fields, and plastic pinning at high applied fields, without showing a secondary peak. However, in the optimally and heavily doped samples, the magnetic relaxation rate and <I>U</I>(<I>J</I>) isothermal analysis show that the collective pinning that dominates below <I>H</I> <SUB>peak</SUB> crosses over to plastic pinning for fields above <I>H</I> <SUB>peak</SUB>.</P>
ERS-1 and CCRS C-SAR Data Integration for Look Direction Bias Correction using Wavelet Transform
J. S. Won,Woo Il M. Moon,Vern Singhroy,Paul D. Lowman Jr 大韓遠隔探査學會 1994 大韓遠隔探査學會誌 Vol.10 No.2
Look direction bias in a single look SAR image can often be misinterpreted in the geological application of radar data. This paper investigates digital processing techniques for SAR image data integration and compensation of the SAR data look direction bias. The two important approaches for reducing look direction bias and integration of multiple SAR data sets are (1) principal component analysis (PCA), and (2) wavelet transform(WT) integration techniques. These two methods were investigated and tested with the ERS-l (VV-polarization) and CCRS*s airborne (HH-polarization) C-SAR image data sets recorded over the Sudbury test site, Canada. The PCA technique has been very effective for integration of more than two layers of digital image data. When there are only two sets of SAR data are available, the PCA technique requires at least one more set of auxiliary data for proper rendition of the fine surface features. The WT processing approach of SAR data integration utilizes the property which decomposes images into approximated image (low frequencies) characterizing the spatially large and relatively distinct structures, and detailed image (high frequencies) in which the information on detailed fine structures are preserved. The test results with the ERS-l and CCRS*s C-SAR data indicate that the new WT approach is more efficient and robust in enhancing the fine details of the multiple SAR images than the PCA approach.