研究者業績
基本情報
- 所属
- 国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 教授総合研究大学院大学 物理科学研究科 教授青山学院大学 大学院理工学研究科 客員教授
- 学位
- 理学博士(1991年2月 東京大学)
- J-GLOBAL ID
- 200901011121067404
- researchmap会員ID
- 1000013960
「初期宇宙の素粒子的描像での理解」を目指して低エネルギー反粒子宇宙線観測気球実験に参画。2006年からは自ら気球実験を実施してきた経験をベースに，日本で唯一気球実験を運営しているJAXA宇宙科学研究所の教授に着任し，大気球実験の実施責任者として大学の研究者等による宇宙科学研究を推進している。大気球，観測ロケットといった小型飛翔体による科学成果の創出に加えて宇宙科学研究を場とした幅広い人材育成への貢献にも取り組んでいる。
主要な研究キーワード
25経歴
7-
2010年4月 - 現在
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2006年4月 - 2010年3月
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1997年4月 - 2006年3月
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1996年10月 - 1997年3月
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1994年4月 - 1996年9月
学歴
2-
1985年4月 - 1991年2月
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1981年4月 - 1985年3月
委員歴
7-
2013年2月 - 2015年1月
受賞
1論文
195-
Physical Review Letters 132(13) 2024年3月25日 査読有り
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Journal of Evolving Space Activities 1 77 2023年12月 査読有り
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Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023) 2023年8月9日
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J. Evolving Space Activities 1 2023年4月 査読有り
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Journal of Evolving Space Activities 1 n/a 2023年4月 査読有りThe General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment that aims to measure low-energy cosmicray antiparticles. GAPS has developed a new antiparticle identification technique based on exotic atom formation caused by incident particles, which is achieved by ten layers of Si(Li) detector tracker in GAPS. The conventional analysis uses the physical quantities of the reconstructed incident and secondary particles. In parallel with this, we have developed a complementary approach based on deep neural networks. This paper presents a new convolutional neural network (CNN) technique. A three-dimensional CNN takes energy depositions as three-dimensional inputs and learns to identify their positional/energy correlations. The combination of the physical quantities and the CNN technique is also investigated. The findings show that the new technique outperforms existing machine learning-based methods in particle identification.
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Astroparticle Physics 145 102791-102791 2023年
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Journal of Low Temperature Physics 209(3-4) 396-408 2022年9月5日
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Proceedings of Science 395 2022年3月18日Low-energy cosmic ray antideuterons (< 0.25 GeV/n) are a compelling, mostly uncharted channel of many viable dark matter models and benefit from highly suppressed astrophysical background. The General Antiparticle Spectrometer (GAPS) is a first-of-its-kind exotic-atom-based Antarctic balloon-borne experiment specialized for detection of low-energy antiprotons, antideuterons, and antihelium with a targeted launch in 2022. The results of novel technology development and a summary of current construction status are the focus of this contribution. GAPS exploits a novel antiparticle identification technique based on exotic atom formation and decay, allowing more active target material for a larger overall acceptance since no magnet is required. The GAPS instrument consists of a large-area (∼ 50 m2) scintillator time-of-flight, ten planes of custom silicon detectors with dedicated ASIC readout, and a novel oscillating heat pipe cooling approach. This contribution will briefly introduce the exotic atom detection technique. Following this, the instrument design will be discussed and detailed description of experimental hardware and expected performance will be presented. I will conclude with recent construction and testing progress while also highlighting developments of a scaled, integrated prototype.
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Proceedings of Science 395 2022年3月18日At low energies, cosmic antideuterons and antihelium provide an ultra-low background signature of dark matter annihilation, decay, and other beyond the Standard Model phenomena. The General Antiparticle Spectrometer (GAPS) is an Antarctic balloon experiment designed to search for low-energy (0.1−0.3 GeV/n) antinuclei, and is planned to launch in the austral summer of 2022. While optimized for an antideuteron search, GAPS also has unprecedented capabilites for the detection of low-energy antihelium nuclei, utilizing a novel detection technique based on the formation, decay, and annihilation of exotic atoms. The AMS-02 collaboration has recently reported several antihelium nuclei candidate events, which sets GAPS in a unique position to set constraints on the cosmic antihelium flux in an energy region which is essentially free of astrophysical background. In this contribution, we illustrate the capabilities of GAPS to search for cosmic antihelium-3 utilizing complete instrument simulations, event reconstruction, and the inclusion of atmospheric effects. We show that GAPS is capable of setting unprecedented limits on the cosmic antihelium flux, opening a new window on exotic cosmic physics.
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Proceedings of Science 395 2022年3月18日The General Antiparticle Spectrometer (GAPS) is the first experiment optimized to identify low-energy (.0.25 GeV/n) cosmic antinuclei, in particular antideuterons from dark matter annihilation or decay. The GAPS program will deliver unprecedented sensitivity to cosmic antideuterons, an essentially background-free signature of various dark matter models, as well as a high-statistics antiproton spectrum in the unexplored low-energy range, and leading sensitivity to cosmic antihelium. GAPS is currently under construction. The first Antarctic balloon flight of GAPS is planned for late 2022, and two additional flights are planned for the coming years. Based on measurements of our custom-developed instrument technology, including large-area lithium-drifted silicon (Si(Li)) detectors and a large-acceptance time-of-flight system, as well as detailed instrument simulation and reconstruction studies, we present here the anticipated impact of the GAPS program on dark matter searches. This contribution discusses the current status of cosmic antinuclei studies while focusing on the science potential of GAPS.
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Proceedings of Science 395 2022年3月18日The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment, scheduled for a first flight in the austral summer 2022. It is designed to measure low energy (< 0.25 GeV/n) cosmic antinuclei. A particular focus is on antideuterons, which are predicted to have an ultra-low astrophysical background as compared to signals from dark matter annihilation or decay in the Galactic halo. GAPS uses a novel technique for particle identification based on the formation and decay of exotic atoms. To achieve sufficient rejection power for particle identification, an accurate determination of several fundamental quantities is needed. The precise reconstruction of the energy deposition pattern on the primary track is a particularly intricate problem and we developed a strategy devised to solve this using modern machine learning techniques. In the future, this approach can also be used for particle identification. Here, we present preliminary results of these efforts obtained from simulations.
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Proceeding of Science (ICRC2021) 132 2022年
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Proceeding of Science (ICRC2021) 395 136 2022年The General Antiparticle Spectrometer (GAPS) experiment is a balloon payload designed to measure low-energy cosmic antinuclei during at least three ∼35-day Antarctic flights, with the first flight planned for December, 2022. With its large geometric acceptance and novel exotic atom-based particle identification method, GAPS will detect ∼1000 antiprotons per flight, producing a precision cosmic antiproton spectrum in the kinetic energy range of 0.03 − 0.23 GeV/n at float altitude (corresponding to 0.085 − 0.30 GeV/n at the top of the atmosphere). With these high statistics in a measurement extending to lower energy than any previous experiment, and with orthogonal sources of systematic uncertainty compared to measurements made using traditional magnetic spectrometer techniques, the GAPS antiproton measurement will be sensitive to physics including dark matter annihilation, primordial black hole evaporation, and cosmic ray propagation. The antiproton measurement will also validate the GAPS exotic atom technique for the antideuteron and antihelium rare-event searches and provide insight into models of cosmic particle attenuation and production in the atmosphere. This contribution demonstrates the GAPS sensitivity to antiprotons using a full instrument simulation, event reconstruction, and solar and atmospheric effects.
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Proceeding of Science (ICRC2021) 504 2022年
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Astroparticle Physics 130 102580-102580 2021年3月 査読有り
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Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave 2020年12月21日
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Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X 2020年12月16日
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Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave 2020年12月15日
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Proceeding of Science (ICRC2019) 37 2020年
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Journal of Cosmology and Astroparticle Physics 2020(8) 035-035 2020年8月18日 査読有り
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TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN 18(3) 44-50 2020年 査読有り
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2018年12月Experiments aiming to directly detect dark matter (DM) particles have yet to make robust detections, thus underscoring the need for complementary approaches such as searches for new particles at colliders, and indirect DM searches in cosmic-ray spectra. Low energy (< 0.25 GeV/n) cosmic-ray antiparticles such as antideuterons are strong candidates for probing DM models, as the yield of these particles from DM processes can exceed the astrophysical background by more than two orders of magnitude. The General Antiparticle Spectrometer (GAPS), a balloon borne cosmic-ray detector, will perform an ultra-low background measurement of the cosmic antideuteron flux in the regime < 0.25 GeV/n, which will constrain a wide range of DM models. GAPS will also detect approximately 1000 antiprotons in an unexplored energy range throughout one long duration balloon (LDB) flight, which will constrain < 10 GeV DM models and validate the GAPS detection technique. Unlike magnetic spectrometers, GAPS relies on the formation of an exotic atom within the tracker in order to identify antiparticles. The GAPS tracker consists of ten layers of lithium-drifted silicon detectors which record dE/dx deposits from primary and nuclear annihilation product tracks, as well as measure the energy of the exotic atom deexcitation X-rays. A two-layer, plastic scintillator time of flight (TOF) system surrounds the tracker and measures the particle velocity, dE/dx deposits, and provides a fast trigger to the tracker. The nuclear annihilation product multiplicity, deexcitation X-ray energies, TOF, and stopping depth are all used together to discern between antiparticle species. This presentation provided an overview of the GAPS experiment, an update on the construction of the tracker and TOF systems, and a summary of the expected performance of GAPS in light of the upcoming LDB flight from McMurdo Station, Antarctica in 2020....
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2018年12月The General Antiparticle Spectrometer (GAPS) is designed to carry out indirect dark matter search by measuring low-energy cosmic-ray antiparticles. Below a few GeVs the flux of antiparticles produced by cosmic-ray collisions with the interstellar medium is expected to be very low and several well-motivated beyond-standard models predict a sizable contribution to the antideuteron flux. GAPS is planned to fly on a long-duration balloon over Antarctica in the austral summer of 2020. The primary detector is a 1m3 central volume containing planes of Si(Li) detectors. This volume is surrounded by a time-of-flight system to both trigger the Si(Li) detector and reconstruct the particle tracks. The detection principle of the experiment relies on the identification of the antiparticle annihilation pattern. Low energy antiparticles slow down in the apparatus and they are captured in the medium to form exotic excited atoms, which de-excite by emitting characteristic X-rays. Afterwards they undergo nuclear annihilation, resulting in a star of pions and protons. The simultaneous measurement of the stopping depth and the dE/dx loss of the primary antiparticle, of the X-ray energies and of the star particle-multiplicity provides very high rejection power, that is critical in rare-event search. GAPS will be able to perform a precise measurement of the cosmic antiproton flux below 250 MeV, as well as a sensitive search for antideuterons....
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2018年9月The General AntiParticle Spectrometer (GAPS) is a balloon-borne instrument designed to detect cosmic-ray antimatter using the novel exotic atom technique, obviating the strong magnetic fields required by experiments like AMS, PAMELA, or BESS. It will be sensitive to primary antideuterons with kinetic energies of $\approx0.05-0.2$ GeV/nucleon, providing some overlap with the previously mentioned experiments at the highest energies. For $3\times35$ day balloon flights, and standard classes of primary antideuteron propagation models, GAPS will be sensitive to $m_{\mathrm{DM } }\approx10-100$ GeV c$^{-2}$ WIMPs with a dark-matter flux to astrophysical flux ratio approaching 100. This clean primary channel is a key feature of GAPS and is crucial for a rare event search. Additionally, the antiproton spectrum will be extended with high statistics measurements to cover the $0.07 \leq E \leq 0.25 $ GeV domain. For $E>0.2$ GeV GAPS data will be complementary to existing experiments, while $E<0.2$ GeV explores a new regime. The first flight is scheduled for late 2020 in Antarctica. These proceedings will describe the astrophysical processes and backgrounds relevant to the dark matter search, a brief discussion of detector operation, and construction progress made to date....
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Journal of Astronomical Instrumentation 6 1740005 2017年 査読有り
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Proceedings of Science 2017年 査読有り© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International License (CC BY-NC-ND 4.0). The GAPS experiment is designed to carry out a sensitive dark matter search by measuring low-energy cosmic ray antideuterons and antiprotons. GAPS will provide a new avenue to access a wide range of dark matter models and masses that is complementary to direct detection techniques, collider experiments and other indirect detection techniques. Well-motivated theories beyond the Standard Model contain viable dark matter candidates which could lead to a detectable signal of antideuterons resulting from the annihilation or decay of dark matter particles. The dark matter contribution to the antideuteron flux is believed to be especially large at low energies (E < 1 GeV), where the predicted flux from conventional astrophysical sources (i.e. from secondary interactions of cosmic rays) is very low. The GAPS low-energy antiproton search will provide stringent constraints on less than 10 GeV dark matter, will provide the best limits on primordial black hole evaporation on Galactic length scales, and will explore new discovery space in cosmic ray physics. Unlike other antimatter search experiments such as BESS and AMS that use magnetic spectrometers, GAPS detects antideuterons and antiprotons using an exotic atom technique. This technique, and its unique event topology, will give GAPS a nearly background-free detection capability that is critical in a rare-event search. GAPS is designed to carry out its science program using long-duration balloon flights in Antarctica. A prototype instrument was successfully flown from Taiki, Japan in 2012. GAPS has now been approved by NASA to proceed towards the full science instrument, with the possibility of a first long-duration balloon flight in late 2020. This presentation will motivate low-energy cosmic ray antimatter searches and it will discuss the current status of the GAPS experiment and the design of the payload.
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Advances in Space Research 60(4) 806-814 2017年8月 査読有りThe balloon-borne experiment with a superconducting spectrometer (BESS) instrument was developed as a high-resolution, high-geometric-acceptance magnetic-rigidity spectrometer for sensitive measurements of cosmic-ray antiparticles, searches for antinuclei, and precise measurements of the absolute fluxes of light GCR elements and isotopes. The original BESS experiment flew 8 times over Lynn Lake, Canada and once from Fort Sumner, USA during the period of 1993 through 2002, with continuous improvement in the instrument. Based on the instrument concept inherited from the BESS spectrometer, a very low instrumental energy cutoff for antiprotons was achieved with a new thin-walled superconducting magnet and removal of the outer pressure vessel for BESS-Polar project. The first and second scientific flights called BESS-Polar I/II were successfully performed, over Antarctica in 2004 December and 2007 December respectively. We report the scientific results, focusing on the long-duration flights of BESS-Polar I (2004) and BESS-Polar II (2007-2008). (C) 2017 COSPAR. Published by Elsevier Ltd. All rights reserved.
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Astrophysical Journal 822(2) 2016年5月 査読有りThe BESS-Polar Collaboration measured the energy spectra of cosmic-ray protons and helium during two long-duration balloon flights over Antarctica in 2004 December and 2007 December at substantially different levels of solar modulation. Proton and helium spectra probe the origin and propagation history of cosmic rays in the galaxy, and are essential to calculations of the expected spectra of cosmic-ray antiprotons, positrons, and electrons from interactions of primary cosmic-ray nuclei with the interstellar gas, and to calculations of atmospheric muons and neutrinos. We report absolute spectra at the top of the atmosphere for cosmic-ray protons in the kinetic energy range 0.2-160 GeV and helium nuclei in the range 0.15-80 GeV/nucleon. The corresponding magnetic-rigidity ranges are 0.6-160 GV for protons and 1.1-160 GV for helium. These spectra are compared to measurements from previous BESS flights and from ATIC-2, PAMELA, and AMS-02. We also report the ratio of the proton and helium fluxes from 1.1 to 160 GV and compare this to the ratios from PAMELA and AMS-02.
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Journal of Low Temperature Physics 184(3-4) 824-831 2016年8月 査読有りLiteBIRD is a proposed CMB polarization satellite project to probe the inflationary B-mode signal. The satellite is designed to measure the tensor-to-scalar ratio with a 68 % confidence level uncertainty of , including statistical, instrumental systematic, and foreground uncertainties. LiteBIRD will observe the full sky from the second Lagrange point for 3 years. We have a focal plane layout for observing frequency coverage that spans 40-402 GHz to characterize the galactic foregrounds. We have two detector candidates, transition-edge sensor bolometers and microwave kinetic inductance detectors. In both cases, a telecentric focal plane consists of approximately superconducting detectors. We will present the mission overview of LiteBIRD, the project status, and the TES focal plane layout.
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Proceedings of SPIE - The International Society for Optical Engineering 9143 2014年 査読有りWe present the mission design of LiteBIRD, a next generation satellite for the study of B-mode polarization and inflation from cosmic microwave background radiation (CMB) detection. The science goal of LiteBIRD is to measure the CMB polarization with the sensitivity of δr = 0:001, and this allows testing the major single-field slow-roll inflation models experimentally. The LiteBIRD instrumental design is purely driven to achieve this goal. At the earlier stage of the mission design, several key instrumental specifications, e.g. observing band, optical system, scan strategy, and orbit, need to be defined in order to process the rest of the detailed design. We have gone through the feasibility studies for these items in order to understand the tradeoffs between the requirements from the science goal and the compatibilities with a satellite bus system. We describe the overview of LiteBIRD and discuss the tradeoffs among the choices of scientific instrumental specifications and strategies. The first round of feasibility studies will be completed by the end of year 2014 to be ready for the mission definition review and the target launch date is in early 2020s.
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Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 735 24-38 2014年1月 査読有りThe General Antiparticle Spectrometer (GAPS) experiment is a novel approach for the detection of cosmic ray antiparticles. A prototype GAPS (pGAPS) experiment was successfully flown on a high-altitude balloon in June of 2012. The goals of the pGAPS experiment were: to test the operation of lithium drifted silicon (Si(Li)) detectors at balloon altitudes, to validate the thermal model and cooling concept needed for engineering of a full-size GAPS instrument, and to characterize cosmic ray and X-ray backgrounds. The instrument was launched from the Japan Aerospace Exploration Agency's (JAXA) Taiki Aerospace Research Field in Hokkaido, Japan. The flight lasted a total of 6 h, with over 3 h at float altitude ( similar to 33 km). Over one million cosmic ray triggers were recorded and all flight goals were met or exceeded. (C) 2013 Elsevier B.V. All rights reserved.
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Journal of Low Temperature Physics 176(5-6) 733-740 2014年9月 査読有りLiteBIRD is a next-generation satellite mission to measure the polarization of the cosmic microwave background (CMB) radiation. On large angular scales the B-mode polarization of the CMB carries the imprint of primordial gravitational waves, and its precise measurement would provide a powerful probe of the epoch of inflation. The goal of LiteBIRD is to achieve a measurement of the characterizing tensor to scalar ratio to an uncertainty of . In order to achieve this goal we will employ a kilo-pixel superconducting detector array on a cryogenically cooled sub-Kelvin focal plane with an optical system at a temperature of 4 K. We are currently considering two detector array options; transition edge sensor (TES) bolometers and microwave kinetic inductance detectors. In this paper we give an overview of LiteBIRD and describe a TES-based polarimeter designed to achieve the target sensitivity of 2 K arcmin over the frequency range 50-320 GHz.
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Astroparticle Physics 54 93-109 2014年2月 査読有りThe General AntiParticle Spectrometer experiment (GAPS) is foreseen to carry out a dark matter search using low-energy cosmic ray antideuterons at stratospheric altitudes with a novel detection approach. A prototype flight from Taiki, Japan was carried out in June 2012 to prove the performance of the GAPS instrument subsystems (Lithium-drifted Silicon tracker and time-of-flight) and the thermal cooling concept as well as to measure background levels. The flight was a success and the stable flight operation of the GAPS detector concept was proven. During the flight about 10(6) charged particle triggers were recorded, extensive X-ray calibrations of the individual tracker modules were performed by using an onboard X-ray tube, and the background level of atmospheric and cosmic X-rays was measured. The behavior of the tracker performance as a function of temperature was investigated. The tracks of charged particle events were reconstructed and used to study the tracking resolution, the detection efficiency of the dacker, and coherent X-ray backgrounds. A timing calibration of the time-of-flight subsystem was performed to measure the particle velocity. The flux as a function of flight altitude and as a function of velocity was extracted taking into account systematic instrumental effects. The developed analysis techniques will form the basis for future flights. (C) 2013 Elsevier B.V. All rights reserved.
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Advances in Space Research 53(10) 1426-1431 2014年5月 査読有りThe Balloon-borne Experiment with a Superconducting Spectrometer (BESS) is configured with a solenoidal superconducting magnet and a suite of precision particle detectors, including time-of-flight hodoscopes based on plastic scintillators, a silica-aerogel Cherenkov detector, and a high resolution tracking system with a central jet-type drift chamber. The charges of incident particles are determined from energy losses in the scintillators. Their magnetic rigidities (momentum/charge) are measured by reconstructing each particle trajectory in the magnetic field, and their velocities are obtained by using the time-of-flight system. Together, these measurements can accurately identify helium isotopes among the incoming cosmic-ray helium nuclei up to energies in the GeV per nucleon region. The BESS-Polar I instrument flew for 8.5 days over Antarctica from December 13th to December 21st, 2004. Its long-duration flight and large geometric acceptance allow the time variations of isotopic fluxes to be studied for the first time. The time variations of helium isotope fluxes are presented here for rigidities from 1.2 to 2.5 GV and results are compared to previously reported proton data and neutron monitor data. Published by Elsevier Ltd. on behalf of COSPAR.
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Advances in Space Research 53(10) 1432-1437 2014年5月 査読有りThe General Anti-Particle Spectrometer (GAPS) project is being carried out to search for primary cosmic-ray antiparticles especially for antideuterons produced by cold dark matter. GAPS plans to realize the science observation by Antarctic long duration balloon flights in the late 2010s. In preparation for the Antarctic science flights, an engineering balloon flight using a prototype of the GAPS instrument, "pGAPS", was successfully carried out in June 2012 in Japan to verify the basic performance of each GAPS subsystem. The outline of the pGAPS flight campaign is briefly reported. (C) 2013 COSPAR. Published by Elsevier Ltd. All rights reserved.
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Journal of Atmospheric and Oceanic Technology 31(7) 1540-1548 2014年7月 査読有りA balloon-borne cryogenic air sampling experiment was carried out over the ocean near the equator to elucidate the transport process of greenhouse gases in the stratosphere. Four air samplers were launched from the deck of the Research Vessel Hakuho Maru by four individual balloons. To realize a balloon launch from this vessel's narrow deck, a new launch method was developed, based on the conventional static launch method. After the balloon flight, each of the four samplers parachuted down to the sea and was recovered by the vessel itself. Details of this successful shipboard balloon operation, including the new launch method, are described.
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Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013 2013-October 2013年 査読有り© 2013 Sociedade Brasileira de Fisica. All Rights Reserved. We are promoting the project of 10MeV-100GeV cosmic gamma-ray observation with precise (0.08deg@1-2GeV) and polarization sensitive large aperture area (∼10m2) emulsion telescope by repeating long duration balloon flights. We call this project GRAINE (Gamma-Ray Astro-Imager with Nuclear Emulsion). An overview and the status of the GRAINE project are described.
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Proceedings of the 33rd International Cosmic Rays Conference, ICRC 2013 2013-October 2013年 査読有り© 2013 Sociedade Brasileira de Fisica. All Rights Reserved. We are furthering our GRAINE project. This balloon experiment was performed using a telescope with a 12.5cm×10cm aperture area and a 4.3hour (1.6hours@35km) flight duration in 2011. Working tests of each element and connection tests between elements were performed. Atmospheric gamma-ray flux was measured. The first demonstration of an emulsion gamma-ray telescope was described using flight data in our 2011 balloon experiment.
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Advances in Space Research 51(2) 227-233 2013年1月15日 査読有りThe balloon-borne experiment with a superconducting spectrometer (BESS) has performed cosmic-ray observations as a US-Japan cooperative space science program, and has provided fundamental data on cosmic rays to study elementary particle phenomena in the early Universe. The BESS experiment has measured the energy spectra of cosmic-ray antiprotons to investigate signatures of possible exotic origins such as dark matter candidates or primordial black holes, and searched for heavier antinuclei that might reach Earth from antimatter domains formed in the early Universe. The apex of the BESS program was reached with the Antarctic flight of BESS-Polar II, during the 2007-2008 Austral Summer, that obtained over 4.7 billion cosmic-ray events from 24.5 days of observation. The flight took place at the expected solar minimum, when the sensitivity of the low-energy antiproton measurements to a primary source is greatest. Here, we report the scientific results, focusing on the long-duration flights of BESS-Polar I (2004) and BESS-Polar II (2007-2008). © 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
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Advances in Space Research 51(2) 234-237 2013年1月 査読有りThe Balloon-borne Experiment with a Superconducting Spectrometer (BESS) was flown from Lynn Lake, Manitoba, Canada in August, 2000, during the maximum solar modulation period, with an average residual atmospheric overburden of 4.3 g/cm(2). Precise spectral measurements of cosmic ray hydrogen isotopes from 0.178 GeV/n to 1.334 GeV/n were made during the 28.7 h of flight. This paper presents the measured energy spectra and their ratio, H-2/H-1. The results are also compared with previous measurements and theoretical predictions. (c) 2012 COSPAR. Published by Elsevier Ltd. All rights reserved.
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Advances in Space Research 51(2) 290-296 2013年1月 査読有りThe General Antiparticle Spectrometer (GAPS) is a new approach to the indirect detection of dark matter. It relies on searching for primary antideuterons produced in the annihilation of dark matter in the galactic halo. Low energy antideuterons produced through Standard Model processes, such as collisions of cosmic-rays with interstellar baryons, are greatly suppressed compared to primary antideuterons. Thus a low energy antideuteron search provides a clean signature of dark matter. In GAPS antiparticles are slowed down and captured in target atoms. The resultant exotic atom deexcites with the emission of X-rays and annihilation pions, protons and other particles. A tracking geometry allows for the detection of the X-rays and particles, providing a unique signature to identify the mass of the antiparticle. A prototype detector was successfully tested at the KEK accelerator in 2005, and a prototype GAPS balloon flight is scheduled for 2011. This will be followed by a full scale experiment on a long duration balloon from Antarctica in 2014. We discuss the status and future plans for GAPS. (c) 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
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Physical Review Letters 108(13) 131301 2012年3月 査読有りIn two long-duration balloon flights over Antarctica, the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) collaboration has searched for antihelium in the cosmic radiation with the highest sensitivity reported. BESS-Polar I flew in 2004, observing for 8.5 days. BESS-Polar II flew in 2007-2008, observing for 24.5 days. No antihelium candidate was found in BESS-Polar I data among 8.4 x 10(6) vertical bar Z vertical bar = 2 nuclei from 1.0 to 20 GV or in BESS-Polar II data among 4: 0 x 10(7) vertical bar Z vertical bar = 2 nuclei from 1.0 to 14 GV. Assuming antihelium to have the same spectral shape as helium, a 95% confidence upper limit to the possible abundance of antihelium relative to helium of 6.9 x 10(-8) was determined combining all BESS data, including the two BESS-Polar flights. With no assumed antihelium spectrum and a weighted average of the lowest antihelium efficiencies for each flight, an upper limit of 1.0 x 10(-7) from 1.6 to 14 GV was determined for the combined BESS-Polar data. Under both antihelium spectral assumptions, these are the lowest limits obtained to date.
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Advances in Space Research 49(4) 613-620 2012年2月 査読有りDevelopmmt of a balloon to fly at higher altitudes is one of the most attractive challenges for scientific balloon technologies. After reaching the highest balloon altitude of 53.0 km using the 3.4 mu m film in 2002, a thinner balloon film with a thickness of 2.8 mu m was developed. A 5000 m(3) balloon made with this film was launched successfully in 2004. However, three 60,000 m(3) balloons with the same film launched in 2005, 2006, and 2007, failed during ascent. The mechanical properties of the 2.8 mu m film were investigated intensively to look for degradation of the ultimate strength and its elongation as compared to the other thicker balloon films. The requirement of the balloon film was also studied using an empirical and a physical model assuming an axis-symmetrical balloon shape and the static pressure. It was found that the film was strong enough. A stress due to the dynamic pressure by the wind shear is considered as the possible reason for the unsuccessful flights. A 80,000 m(3) balloon with cap films covering 9 m from the balloon top will be launch in 2011 to test the appropriateness of this reinforcement. (C) 2011 COSPAR. Published by Elsevier Ltd. All rights reserved.
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大気球シンポジウム: 2022年度 = Balloon Symposium: 2022 2022年11月大気球シンポジウム 2022年度（2022年11月7-8日. ハイブリッド開催（JAXA相模原キャンパス& オンライン)) Balloon Symposium 2022 (November 7-8, 2022. Hybrid(in-person & online) Conference (Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan 著者人数: 26名 資料番号: SA6000177012 レポート番号: isas22-sbs-012
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宇宙航空研究開発機構宇宙科学研究所大気球シンポジウム (2021年度) isas21-sbs-032 2021年11月2日
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宇宙航空研究開発機構宇宙科学研究所大気球シンポジウム (2021年度) isas21-sbs-029 2021年11月2日大気球シンポジウム 2021年度（2021年11月1-2日. オンライン開催) Balloon Symposium 2021 (November 1-2, 2021. Online Meeting) 著者人数: 18名 資料番号: SA6000166029 レポート番号: isas21-sbs-029
書籍等出版物
4-
"Neutrino Oscillation and their Origin", eds. Y.Suzuki, M.Nakahata, M.Miura and K.Kaneyuki, World Scientific. 2001年
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Neutrino Oscillation and their Origin", eds. Y.Suzuki, M.Nakahata, M.Miura and K.Kaneyuki, World Scientific. 2001年
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Proc. of 21st Intl. Symposium Space Technology and Science 1998年
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Proc. of 21st Intl. Symposium Space Technology and Science 1998年
講演・口頭発表等
24担当経験のある科目(授業)
3-
最新物理講義 (青山学院大学理学部)
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宇宙工学概論 (総合研究大学院大学物理科学研究科宇宙科学専攻)
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宇宙システム工学特論I (総合研究大学院大学物理科学研究科宇宙科学専攻)
所属学協会
4共同研究・競争的資金等の研究課題
16-
日本学術振興会 科学研究費助成事業 2014年4月 - 2017年3月
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日本学術振興会 科学研究費補助金 2010年4月 - 2014年3月
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日本学術振興会 科学研究費補助金 2009年7月 - 2014年3月
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日本学術振興会 科学研究費助成事業 2006年 - 2009年
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日本学術振興会 科学研究費助成事業 2001年 - 2005年
