1,721,046 research outputs found
Predicted CALET measurements of ultra-heavy cosmic ray relative abundances
No full textThe CALorimetric Electron Telescope (CALET) is an imaging calorimeter under construction for launch to the ISS in 2014 for a planned 5 year mission. CALET consists of a charge detection module (CHD) with two segmented planes of 1 cm thick plastic scintillator, an imaging calorimeter (IMC) with a total of 3 radiation lengths (X-o) of tungsten plates read out with 8 planes of interleaved scintillating fibers, and a total absorption calorimeter (TASC) with 27 X-o of lead tungstate (PWO) logs. The primary objectives of the instrument are to measure electron energy spectra from 1 GeV to 20 TeV, to detect gamma-rays above 10 GeV, and to measure the energy spectra of nuclei from protons through iron up to 1,000 TeV. In this paper we describe how the geomagnetic field at the 51.6 degrees inclination orbit of the ISS can be used to allow CALET to measure the rare ultra-heavy (UH) cosmic ray (CR) abundances, which provide important clues for the CR source and acceleration mechanism. The CHD scintillator response is relatively insensitive to energy above minimum ionization, and the angle-dependent rigidity as a function of geomagnetic latitude can be exploited to discriminate particles above this energy threshold. Such events require corrections for trajectory in instrument that can be made with only the top 4 layers of the IMC, which allows for considerably greater geometric acceptance than for events that require passage through the TASC for energy determination. Using this approach CALET will be able to measure UH CR relative abundances over its expected mission with superior statistics to previous space instruments. (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved
Gamma-Ray Observations with CALET: Exposure Map, Response Functions, and Simulated Results
No full textThe 34th International Cosmic Ray Conference; The Hague, The Netherlands; 30 July - 6 August, 2015The CALorimetric Electron Telescope (CALET) is a space-borne cosmic ray instrument planned for installation on the JEM-EF platform on the International Space Station (ISS) in 2015. The CALET collaboration is a Japan-led international team involving researchers in Italy and the U.S. In addition to precise measurement of the cosmic ray electron and nuclei spectra, the CALET
calorimeter will be capable of gamma-ray observations in the GeV to tens of TeV energy range. This paper presents a study of the expected gamma-ray signal measured by CALET in the first year on orbit. The ISS zenith pointing is simulated at a time resolution of 1 second in order to estimate the exposure map on the sky. The instrument response functions and simulated results of
gamma-ray/electron separation for the calorimeter are discussed and used to estimate the expected point source and galactic diffuse signals in the energy range ~10 GeV - ~500 GeV based on known fluxes measured by Fermi-LAT.The CALET experiment is supported by NASA in the United States, JAXA in Japan, and ASI in Italy. Portions of this research were conducted with high performance computing resources provided by Louisiana State University (http://www.hpc.lsu.edu). AGI Satellite Toolkit (STK) software was used in the generation of some results in this paper. The authors also appreciate the efforts of the Fermi-LAT team in development of the background models used. Reference was made to the University of Chicago TeVCat catalog for collections of source-related information. Financial support for the lead author partially provided by a Louisiana State University Board of Regents Graduate Fellowship.https://pos.sissa.it/236/995
The CALorimetric Electron Telescope (CALET) space experiment for the direct measurement of high energy electrons in cosmic rays
No full textThe CALorimetric Electron Telescope (CALET) is a Japanese-led international space mission by JANA (Japanese Aerospace Exploraticai Agency) in Collaboration with the Italian Space Agency (ASI) and NASA. The apparatus was launched to the International Space Station on 19 August 2015. Its main objective is to explore the region above 1 TeV with precise direct measurements of the electron positron and nuclei spectra. The instrument consists of a charge detection device composed of two layers of plastic scintillators, a finely-segmented sampling calorimeter with scintillating fibers (3 radiation lengths) and a homogeneous calorimeter made of PWO scintillating bars (27 radiation lengths). In parallel with the calorimeter another instrument, the CALET Gamma-ray Burst Monitor (CCBM), operates as a gamma-ray burst monitor using two different kinds of scindilators to detect photons from 7 keV to 20 51eV. In this work a brief review of the electron analysis Will be discussed focusing on the electron/proton discrimination power estimated with different Monte Carlo simulations. Some published results about calibration and search for electromagnetic counterparts of the LIG G-V 151226 gravitational wave event will be presented too
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
High-Energy Gamma-ray Observations Using the CALorimetric Electron Telescope
No full text35th International Cosmic Ray Conference -ICRC2017; Bexco, Busan, Korea; 10-20 July 2017We present the analysis methodology and preliminary results of the gamma-ray event analysis using the CALorimetric Electron Telescope (CALET). CALET, a 30 radiation length deep calorimeter, was deployed aboard the International Space Station (ISS) in August 2015. In this work we demonstrate the sensitivity of CALET to gamma-rays, the efficiency of separation between gamma-ray and charged particle events, and CALET’s exposure on the sky after the first 17 months of observation. Consistency of the flux of the bright sources Geminga and the Crab with established Fermi-LAT results is discussed and initial results of a search for high-energy counterparts to CALET Gamma-ray Burst Monitor gamma-ray bursts are presented.This work was supported in Japan by JAXA, in Italy by ASI, and in the U.S. by NASA. The author appreciates support provided by the Louisiana Board of Regents. The CERN ROOT4 framework (R. Brun and F. Rademakers, NIM. in Phys. Res. A, 389 (1997)) and the HEALPix package (K.M. Gorski et al., ApJ, 622 (2005)) were used in deriving some results in this work.https://pos.sissa.it/301/720
CALET on-orbit operations and data analysis system at the Waseda CALET Operations Center (WCOC)
No full text35th International Cosmic Ray Conference — ICRC2017; Bexco, Busan, Korea; 10–20 July, 2017CALET is the long-term high energy cosmic ray observation mission on JEM-EF of the International Space Station. In order to extend measurements of electrons and gamma rays to the 10-20 TeV region and protons and nuclei to several hundred TeV, the CALET calorimeter (CAL) has a thickness of 30 radiation lengths. CAL is composed of a lead tungstate (PWO) Total AbSorption Calorimeter (TASC), a tungsten-scintillating fiber IMaging Calorimeter (IMC), and a plastic scintillator CHarge Detector (CHD). The data taken by CALET are passed to the ISS and sent to the ground immediately via NASA and JAXA data relay links. At JAXA’s Tsukuba Space Center, a ground operation system (JAXAGSE) then transmits the data to the Waseda CALET Operations Center (WCOC) at Waseda University. Monitoring of the instrument’s observation status has been performed since October 2015 at JAXA. Simultaneously, the CALET science team monitors the scientific mission and the data transmission on a 24-hour 7-day basis in WCOC. Monitoring at the WCOC is performed by Quick Look software developed at Waseda. When the Quick Look GUI detects observed values exceeding predetermined thresholds, an alarm is issued. In order to provide flexibility for the scientific operation, the CALET observing schedule is updated daily. In addition, the observation data file is processed for transmission to the science team. Raw (Level-0) data processed at JAXA-GSE are converted to engineering (Level-1) data for distribution to the international CALET collaboration. Finally, individual detector temperature dependences, time variations, etc. are included in the final (Level-2) data which are used for detailed science analysis.We gratefully acknowledge JAXA’s contributions to the development of CALET and to the operations on board the ISS. We also wish to express our sincere gratitude to ASI and NASA for their support of the CALET project. Finally, this work was partially supported by a JSPS Grant-in-Aid for Scientific Research (S) (no.26220708) and by the MEXT-Supported Program for the Strategic Research Foundation at Private Universities(2011-2015) (no.S1101021) at Waseda University.https://pos.sissa.it/301/165
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
