24,820 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
Development of the Waseda CALET Operations Center (WCOC) for Scientific Operations of CALET
No full textThe 34th International Cosmic Ray Conference; The Hague, The Netherlands; 30 July- 6 August, 2015The CALET project aims at a long duration observation of high energy cosmic rays onboard the International Space Station (ISS). The CALET detector features a very thick calorimeter of 30 radiation-lengths which consists of imaging and total absorption calorimeters. It will directly measure the cosmic-ray electron spectrum in the energy range of 1GeV–20TeV with 2 % energy resolution. The data obtained with CALET onboard ISS will be transferred to JAXA using two data relay satellite systems operated by NASA and JAXA, respectively. To operate the CALET onboard ISS, the CALET Ground Support Equipment (CALET-GSE) is being prepared in JAXA. Simultaneously, Waseda CALET Operations Center (WCOC) is being established to perform operations and monitoring related to the scientific mission. The real-time data received by CALET-GSE is immediately transferred to WCOC. Scientific raw data are also transferred to WCOC on an hourly basis after time-order correcting and complementing replay data. Mission operations at WCOC includes the following roles: 1. Real-time monitoring and operations: To monitor the CALET observation and its status in real-time, Quick Look (QL) programs are developed to visualize and summarize both cosmic-ray event data and housekeeping data. Operators at WCOC use QLs to understand the CALET situation and validate the observation on orbit in 24 hour. Upon necessity,
appropriate commands will be issued through CALET-GSE. 2. Operation planning: Scheduled command sequences are utilized to control the CALET observation mode on orbit. Calibration data taking such as pedestal and penetrating particle events, low energy electron data taking at high geomagnetic latitude, and other dedicated trigger modes can be scheduled along with the ISS orbit. 3. Scientific data processing: The scientific raw data called CALET Level-0 data are processed to CALET Level-1 data, and Level-1 data are distributed to the collaboration for scientific analysis. Quick analyses based on both Level-0 and Level-1 data are performed and their results are used to feedback for better operation planning and real-time monitoring. In this contribution, we will review the role of WCOC and report WCOC development.This work was supported by JSPS KAKENHI Grant Number 26220708.https://pos.sissa.it/236/603
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
The CALorimetric Electron Telescope (CALET): High Energy Astroparticle Physics Observatory on the International Space Station
No full textThe 34th International Cosmic Ray Conference; The Hague, The Netherlands; 30 July- 6 August, 2015The CALorimetric Electron Telescope (CALET) space experiment, which has been developed by Japan in collaboration with Italy and the United States, is a high-energy astroparticle physics mission to be installed on the International Space Station (ISS). The primary goals of the CALET mission include investigating possible nearby sources of high energy electrons, studying the details of galactic particle propagation and searching for dark matter signatures. During a two-year mission, extendable to five years, the CALET experiment will measure the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma-rays to 10 TeV and nuclei with Z=1 to 40 up to several 100 TeV. The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). CALET has sufficient depth, imaging capabilities and excellent energy resolution to allow for a clear separation between hadrons and electrons and between charged particles and gamma rays. The instrument is currently being prepared for launch on August 16, 2015 to the ISS with HTV-5 (H-II Transfer Vehicle 5) and installed on the Japanese Experiment Module- Exposed Facility
(JEM-EF)The CALET mission is conducted by Japanese space agency, JAXA, in collaboration with NASA and ASI. This work is partially supported by JSPS KAKENHI Grant Number 21224006.https://pos.sissa.it/236/581
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
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
Measurements of heavy nuclei with the CALET experiment
No full text35th International Cosmic Ray Conference — ICRC2017; Bexco, Busan, Korea; 10–20 July, 2017The CALorimetric Electron Telescope, CALET, was installed on the International Space Station in August 2015 and it has been collecting data since October 2015. Direct measurements of the high energy spectra of individual cosmic ray nuclei and of the energy dependence of secondary-to-primary abundance ratios are important for an understanding of the acceleration and propagation of cosmic rays in the galaxy. CALET is able to identify cosmic ray nuclei with individual element resolution and measure their energies in the range from a few tens of GeV to the PeV scale. The instrument consists of two layers of segmented plastic scintillators to measure the particle charge, from Z=1 to 40, a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter, and a 27 radiation length thick PWO calorimeter. In this paper, the capability of charge identification and first results for heavy nuclei (Z>8) up to iron with CALET are presented.This work was supported in part by a JSPS Grand-in-Aid for Scientific Research (S) (No.25220708), and by the joint research program of the Institute for Cosmic Ray Research (ICRR), University of Tokyo. We thank the NASA Center for Climate Simulation for use of the ADAPT computing system. Author (YA) was supported by JSPS Overseas Research Fellowships.https://pos.sissa.it/301/181
Simulation studies of the expected proton rejection capabilities of CALET
No full textThe 34th International Cosmic Ray Conference; The Hague, The Netherlands; 30 July- 6 August, 2015The CALorimetric Electron Telescope (CALET) is a Japanese led international space mission by JAXA (Japanese AeroSpace Agency) in collaboration with the Italian Space Agency (ASI) and NASA. The instrument will be launched to the International Space Station (ISS) in 2015. The major scientific goals for CALET are to measure the flux of cosmic-ray electrons (including positrons) from 1 GeV to 20 TeV, gamma rays to 10 TeV and nuclei from Z=1 to 40 up to 1000 TeV. These measurements are essential to search for dark matter signatures, investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy and discover possible astrophysical sources of high-energy electrons nearby the Earth.
The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification, a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter and a 27
radiation length thick lead-tungstate calorimeter. Protons are the largest source of background for the high-energy electron observation. As the ratio of protons to electrons increases at higher energies, a proton rejection power better than 10⁵ is necessary to measure the electron spectrum with a proton contamination below a few percent in the TeV region. In this work, a Monte Carlo based study of the proton rejection capability CALET can achieve at TeV energies is presented. Both standard analysis based on consecutive selection criteria and multivariate analysis are applied to simulated samples of signal and background events.CALET (CALorimetric Electron Telescope) is a Japanese-led international mission funded by the Japanese Space Agency (JAXA), the Italian Space Agency (ASI) and NASA.https://pos.sissa.it/236/1196
Gamma-ray burst observations with CALET
No full textAPS April Meeting 2020, Saturday–Tuesday, April 18–21, 2020; Washington D.C.CALET Collaboration Authors: O. Adriani, Y. Akaike, K. Asano, Y. Asaoka, E. Berti, G. Bigongiari, W. R. Binns, M. Bongi, P. Brogi, A. Bruno, J. H. Buckley, N. Cannady, G. Castellini, C. Checchia, M. L. Cherry, G. Collazuol, K. Ebisawa, A. W. Ficklin, H. Fuke, S. Gonzi, T. G. Guzik, T. Hams, K. Hibino, M. Ichimura, K. Ioka, W. Ishizaki, M. H. Israel, K. Kasahara, J. Kataoka, R. Kataoka, Y. Katayose, C. Kato, N. Kawanaka, Y. Kawakubo, K. Kobayashi, K. Kohri, H. S. Krawczynski, J. F. Krizmanic, P. Maestro, P. S. Marrocchesi, A. M. Messineo, J.W. Mitchell, S. Miyake, A. A. Moiseev, M. Mori, N. Mori, H. M. Motz, K. Munakata, S. Nakahira, J. Nishimura, G. A. de Nolfo, S. Okuno, J. F. Ormes, N. Ospina, S. Ozawa, L. Pacini, P. Papini, B. F. Rauch, S. B. Ricciarini, K. Sakai, T. Sakamoto, M. Sasaki, Y. Shimizu, A. Shiomi, P. Spillantini, F. Stolzi, S. Sugita, A. Sulaj, M. Takita, T. Tamura, T. Terasawa, S. Torii, Y. Tsunesada, Y. Uchihori, E. Vannuccini, J. P. Wefel, K. Yamaoka, S. Yanagita, A. Yoshida, K. Yoshida, and W. V. ZoberGamma-ray burst observations with CALET YUTA KAWAKUBO, Louisiana State University, Baton Rouge, NICHOLAS CANNADY, UMBC/CRESST II/NASA GSFC, CALET COLLABORATION — The CALorimetric Electron Telescope (CALET) is a payload deployed on the International Space Station to observe high energy cosmic rays and gamma rays. CALET consists of the CALorimeter (CAL), which is the primary instrument of CALET, and the CALET Gamma-ray Burst Monitor (CGBM), which aims to observe gamma-ray bursts (GRBs). CALET has been in nominal on-orbit operation since October 2015. As of the end of 2019, CGBM has detected 181 GRBs including 22 short GRBs over four years and three months. Also, we have searched for high energy gamma-rays from GRBs with CAL. In this work, we present CALET results of GRB observation, including the search for electromagnetic counterparts of gravitational wave events.https://meetings.aps.org/Meeting/APR20/Session/Y09.
CALET GBM Observations of Gamma-ray Bursts and Gravitational Wave Sources
No full text35th International Cosmic Ray Conference – ICRC2017; Bexco, Busan, Korea; 10-20 July, 2017The CALET Gamma-ray Burst Monitor (CGBM) is secondary scientific instrument of the Calorimetric Electron Telescope (CALET) mission on the International Space Station (ISS). The primary instrument Calorimeter (CAL) is capable of detecting gamma-ray bursts (GRBs) in the GeV-TeV range, and the CGBM was attached to complement CAL gamma-ray observations in the keV-MeV range. The CGBM consists of 2 Hard X-ray Monitors (HXMs) and one Soft Gamma-ray Monitor (SGM), utilizing different scintillators LaBr3
(Ce) and BGO respectively. The CGBM covers a broadband energy range of 7 keV - 20 MeV with a wide field of view (FOV). Since the launch on August 19, 2015, the CGBM has been sucessfully operated on the ISS for about 1.5 years, and detecting about 50 GRBs (roughly 20% short GRBs among them) per year as expected from pre-launch estimation. The CALET also concluded memolandam of understanding (MOU) with LIGO/Virgo collaboration, and we are searching for hard X-ray and gamma-ray counterparts for gravitational wave (GW) sources. In this paper, we will report on CGBM in-orbit operation, performance and observations of GRBs and GW sources.This work is partly supported by Grant-in-Aid (24684015 KY) from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT).https://pos.sissa.it/301/614
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