Search

情報・システム研究機構データサイエンス共同利用基盤施設（ROIS-DS）極域環境データサイエンスセンター（PEDSC）は、極域科学を中心とする科学データの管理や利活用を支援・促進する活動を進めている。その柱の一つが、分野横断型データベースAMIDERの開発である。AMIDERプロジェクトの目標は、専門家でなくとも科学データへアクセスできる環境を整備し、オープンサイエンスや異分野融合研究を促進することである。そのため、生命科学・地球科学・宇宙科学などあらゆる研究分野のデータを統一的インターフェースで閲覧できるデータカタログなどを開発している。, Japan Open Science Summit 2023, 21 Jun. 2023

The 13th Symposium on Polar Science/Ordinary sessions [OS] Space and upper atmospheric sciences, Wed. 16 Nov.

The 13th Symposium on Polar Science/Ordinary sessions [OS] Space and upper atmospheric sciences, Wed. 16 Nov.

異分野融合研究やデータ駆動型研究の推進には、多様な分野の科学データを統合的に扱うための環境整備が必須である。ROIS-DS 極域環境データサイエンスセンターは、極域科学コミュニティの観測・研究活動により取得された科学データの公開と利用を促進する活動を展開している。その柱の一つが、多様なデータを横断的に俯瞰できるデータ公開プラットフォームAMIDER である。将来的には極域科学に留まらないより幅広い分野への適用も目指し、以下の設計コンセプトのもとに開発している。 - 時系列や成分データ、標本情報など、質・分野の異なる科学データであっても統一的なインターフェースで提示する。 - 汎用的なweb デザイン（e コマースなどを参考としたもの）を採用し、専門的な科学データのアクセス性と利便性を高める。 本発表では、AMIDER のシステム設計や開発状況、公開データの整備状況について報告する。 統一的かつユーザーフレンドリーなweb デザインとして構築したのが、サムネイル画像とスニペットで構成されるデータ一覧表示である。スニペットには可能な限り平易な表現を使用し、専門外のユーザーであっても、多様な科学データのコンテンツを一目でイメージできるよう配慮されている。トップページはこのデータ一覧表示とカテゴリフィルターや検索ボックスで構成され、最小限の動作で各データセットのページへ遷移できるように設計されている。 各データセットのページは、メインイメージ画像、データファイルのダウンロード、データプロット画像、関連するデータの一覧、メタデータテーブルで構成される。これらの表示パラメータ（データファイルの形式など）はデータセットごとに設定ファイルで調整でき、多様なデータセットを包括しつつ統一的なユーザーインターフェースを可能にしている。 各データセットのデータファイルへのアクセス性も高められるよう、設計と運用体制を工夫している。データファイルの実体は各研究機関の外部リポジトリに置き、AMIDER システムではそのURI を取得する。きめ細かなデータキュレーションと支援を提供することで、データファイルも可能な限り統一的な形式とする態勢を取っている。Common Data Format (CDF) とNetwork Common Data Form (NetCDF) をデータフォーマットの核としており、それにより、AMIDERでフォーマット変換機能を提供することも可能とした。 さらに、この設計と運用体制により実現したのが、関連するデータ（相関スコアの高いデータ）の提示機能である。AMIDER システムで各データセットのデータファイルを読み取り、データセット間の相関スコアを計算する。それに基づき、各データセットページで関連するデータを提示し、データセット間の「渡り歩き」へ誘導する。相関スコアとしては、現時点では相関係数とEarth mover’s distance を採用している。バッチプログラムの追加により、将来的にさらなる機能拡張も可能である。今年度中に宙空圏や隕石、地震、気象、海洋、生物などの各分野研究者により整備されたデータをシステムへ入力し、関係者内で試験運用を実施する。その結果に基づいてさらにブラッシュアップし、来年度の公開へ備える予定である。 これらの活動を通して、専門外の研究者や教育関係者であってもそれぞれの興味に基づいて科学データを発見し、使用できる環境を整備する。また、異分野のデータを渡り歩く体験を可能とし、異分野融合研究のきっかけを創り出す。 In order to promote cross-disciplinary research and data-driven research, it is essential to arrange an environment to handle scientific data from various fields in an integrated manner. The Polar Environment Data Science Center of the Joint Support-Center for Data Science Research (DS), the Research Organization of Information and Systems (ROIS) aims at promoting the publication and use of scientific data obtained from research activities of the polar science community. One of the key pillars of the PEDSC is development of the AMIDER system, which will enable a cross-disciplinary overview of scientific datasets in various fields. Application of the AMIDER to a wider scientific fields beyond polar science in the future is also considered. Our design concepts are: - Present datasets in various formats and fields, such as space science, geoscience, and bioscience, in a uniform design and interface. - Enhance accessibility and usability of scientific datasets by adopting a general web design used in e-commerce, etc. In this presentation, we will report on the system design, development, and data preparation status of the AMIDER. The uniform and user-friendly design appears in the display of dataset list consisting of thumbnail images and snippets. The snippets are made as simple as possible so that even non-specialized users can imagine the contents at a glance. The top page consists of this data list display, category filters, and search box. Page transition to each dataset page is designed to be realized with a minimum operation of users. Each dataset page consists of the main image, datafile download interface, data plots, list of related datasets, and metadata table. These UI parameters (datafile format, etc.) can be customized in a configuration file for each dataset, enabling a uniform UI design to cover various datasets. The design and operation system are developed so that the accessibility to the datafiles of each dataset is also enhanced. Each datafile is placed in a repository of each research institute, and the AMIDER system acquires the URI. By our careful data curation and support, the datafiles are prepared in a uniform format as much as possible. Common Data Format (CDF) and Network Common Data Form (NetCDF) are the primary data formats. This strategy makes it possible to provide the format conversion function with AMIDER. This design and operation system has also achieved the presentation of related datasets which have relatively high correlation scores with the respective dataset. The AMIDER system reads the datafiles of each dataset and calculates the correlation score between the datasets. Each dataset page presents related datasets based on this score and induces “walk-around” between datasets. The correlation coefficient and Earth mover’s distance are used as the correlation score. Further enhancements of the functions are possible by implementing batch programs in the future. Scientific datasets of geospace, meteorites, earthquakes, meteorology, oceans, and biology will be registered, and test operations will be conducted this year. Further optimization will be made based on the results, and we will prepare for the public release in 2023. The AMIDER project will provide a platform for wide-field researchers or non-specialized educators to discover and use scientific data based on their interests. It will also enable a “walk-around” experience between datasets and create a crossdisciplinary research opportunity., 地球電磁気・地球惑星圏学会 第152回総会及び講演会（2022年秋学会）, 2022年11月7日, 地球電磁気・地球惑星圏学会

AMIDER project aims at promoting open science by providing an integrated database application to explore scientific datasets. The AMIDER system is planned to start operation in 2023 focusing on the fields related to polar science. One of its unique features is the visualization in a uniform format regardless of dataset types. Scientific data in various fields, such as geospace science, atmospheric science, geoscience, and life science, are inclusively displayed with a thumbnail image and snippet for each dataset. This catalog view is designed so that the contents of each dataset can be imagined at a glance, inducing access from a user who is not familiar with the dataset. Each dataset has a uniform design page composed of five sections: main images, a data-download interface, data plots, related dataset links, and a metadata table. The data-download interface not only accesses data repositories but also provides a function to convert data files to the ASCII format from dedicated formats such as Common Data Format (CDF) and Network Common Data Form(NetCDF) in space science. The related dataset section is one of the unique functions of our system; we calculate and register a correlation score between each dataset or data file, and several datasets with relatively high scores are displayed. This function provides users with a cross-disciplinary “walk-around” experience between datasets. These applications are optimized to promote open science and are realized by our careful data curation. Many datasets are ready for publication, and the final preparation of the system is underway., SCAR Open Science Conference 2022, 4 Aug. 2022, SCAR

We demonstrate that global observations of high-energy cosmic rays contribute to understanding unique characteristics of a large-scale magnetic flux rope (MFR) causing a magnetic storm in August 2018. Following a weak interplanetary shock on 25 August 2018, a MFR caused an unexpectedly large geomagnetic storm. It is likely that this event became geoeffective because the MFR was accompanied by a corotating interaction region (CIR) and compressed by high-speed solar wind following the MFR. In fact, a Forbush decrease was observed in cosmic-ray data inside the MFR as expected, and a significant cosmic-ray density increase exceeding the unmodulated level before the shock was also observed near the trailing edge of the MFR. The cosmic-ray density increase can be interpreted in terms of the adiabatic heating of cosmic rays near the trailing edge of the MFR, as the corotating interaction region prevents free expansion of the MFR and results in the compression near the trailing edge. A northeast-directed spatial gradient in the cosmic-ray density was also derived during the cosmic-ray density increase, suggesting that the center of the heating near the trailing edge is located northeast of Earth. The second order anisotropy is observed during the density increase clearly representing an intensity enhancement of cosmic rays with approximately 90 degree pitch angle, possibly indicating the betatron acceleration of CRs during the cosmic-ray density increase and/or accelerated CRs leaking along the magnetic field from the density increase region toward the south where lower CR population is expected. This is one of the best examples demonstrating that the observation of high-energy cosmic rays provides us with information of the three-dimensional macroscopic picture of the interaction between coronal mass ejections and the ambient solar wind, which is essential for prediction of large magnetic storms.

We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and compatible with expectations from the hadronic emission scenario in which gamma rays originate from the decay of $\pi^0$'s produced through the interaction of protons with the interstellar medium in the Galaxy. This is strong evidence that cosmic rays are accelerated beyond PeV energies in our Galaxy and spread over the Galactic disk., Comment: Accepted for publication in the Physical Review Letters

We report observations of gamma-ray emissions with energies in the 100 TeV energy region from the Cygnus region in our Galaxy. Two sources are significantly detected in the directions of the Cygnus OB1 and OB2 associations. Based on their positional coincidences, we associate one with a pulsar PSR J2032+4127 and the other mainly with a pulsar wind nebula PWN G75.2+0.1 with the pulsar moving away from its original birthplace situated around the centroid of the observed gamma-ray emission. This work would stimulate further studies of particle acceleration mechanisms at these gamma-ray sources., Accepted for publication in the Physical Review Letters

Cosmic rays (protons and other atomic nuclei) are believed to gain energies of petaelectronvolts (PeV) and beyond at astrophysical particle accelerators called 'PeVatrons' inside our Galaxy. Although a characteristic feature of a PeVatron is expected to be a hard gamma-ray energy spectrum that extends beyond 100 teraelectronvolts (TeV) without a cutoff, none of the currently known sources exhibits such a spectrum due to the low maximum energy of accelerated cosmic rays or insufficient detector sensitivity around 100 TeV. Here we report the observation of gamma-ray emission from the supernova remnant G106.3+2.7 above 10 TeV. This work provides flux data points up to and above 100 TeV and indicates that the very-high-energy gamma-ray emission above 10 TeV is well correlated with a molecular cloud rather than the pulsar PSR J2229+6114. Regarding the gamma-ray emission mechanism of G106.3+2.7, this morphological feature appears to favor a hadronic origin via the {\pi}0 decay caused by accelerated relativistic protons over a leptonic one via the inverse-Compton scattering by relativistic electrons. Furthermore, we point out that an X-ray flux upper limit on the synchrotron spectrum would provide important information to firmly establish the hadronic scenario as the mechanism of particle acceleration at the source., Comment: Published in Nature Astronomy

This work evaluates the viability of polyimide and parylene-C for passivation of lithium-drifted silicon (Si(Li)) detectors. The passivated Si(Li) detectors will form the particle tracker and X-ray detector of the General Antiparticle Spectrometer (GAPS) experiment, a balloon-borne experiment optimized to detect cosmic antideuterons produced in dark matter annihilations or decays. Successful passivation coatings were achieved by thermally curing polyimides, and the optimized coatings form an excellent barrier against humidity and organic contamination. The passivated Si(Li) detectors deliver $\lesssim\,4$ keV energy resolution (FWHM) for 20$-$100 keV X-rays while operating at temperatures of $-$35 to $-45\,^{\circ}$C. This is the first reported successful passivation of Si(Li)-based X-ray detectors operated above cryogenic temperatures., Comment: Accepted for publication at Nuclear Instrumentation and Methods A, 19 pages, 8 figures

We demonstrate that global observations of high-energy cosmic rays contribute to understanding unique characteristics of a large-scale magnetic flux rope causing a magnetic storm in August 2018. Following a weak interplanetary shock on 25 August 2018, a magnetic flux rope caused an unexpectedly large geomagnetic storm. It is likely that this event became geoeffective because the flux rope was accompanied by a corotating interaction region and compressed by high-speed solar wind following the flux rope. In fact, a Forbush decrease was observed in cosmic-ray data inside the flux rope as expected, and a significant cosmic-ray density increase exceeding the unmodulated level before the shock was also observed near the trailing edge of the flux rope. The cosmic-ray density increase can be interpreted in terms of the adiabatic heating of cosmic rays near the trailing edge of the flux rope, as the corotating interaction region prevents free expansion of the flux rope and results in the compression near the trailing edge. A northeast-directed spatial gradient in the cosmic-ray density was also derived during the cosmic-ray density increase, suggesting that the center of the heating near the trailing edge is located northeast of Earth. This is one of the best examples demonstrating that the observation of high-energy cosmic rays provides us with information that can only be derived from the cosmic ray measurements to observationally constrain the three-dimensional macroscopic picture of the interaction between coronal mass ejections and the ambient solar wind, which is essential for prediction of large magnetic storms., Comment: 19 pages, 3 figures, accepted for publication in the Space Weather

Solar modulation of galactic cosmic rays around the solar minimum in 2019–2020 looks different in the secondary neutrons and muons observed at the ground. To compare the solar modulation of primary cosmic rays in detail, we must remove the possible seasonal variations caused by the atmosphere and surrounding environment. As such surrounding environment effects, we evaluate the snow cover effect on neutron count rate and the atmospheric temperature effect on muon count rate, both simultaneously observed at Syowa Station in the Antarctic (69.01° S, 39.59° E). A machine learning technique, Echo State Network (ESN), is applied to estimate both effects hidden in the observed time series of the count rate. We show that the ESN with the input of GDAS data (temperature time series at 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, and 20 hPa) at the local position can be useful for both the temperature correction for muons and snow cover correction for neutrons. The corrected muon count rate starts decreasing in late 2019, preceding the corrected neutron count rate which starts decreasing in early 2020, possibly indicating the rigidity-dependent solar modulation in the heliosphere.

The precise measurement of cosmic-ray antinuclei serves as an important means for identifying the nature of dark matter and other new astrophysical phenomena, and could be used with other cosmic-ray species to understand cosmic-ray production and propagation in the Galaxy. For instance, low-energy antideuterons would provide a "smoking gun" signature of dark matter annihilation or decay, essentially free of astrophysical background. Studies in recent years have emphasized that models for cosmic-ray antideuterons must be considered together with the abundant cosmic antiprotons and any potential observation of antihelium. Therefore, a second dedicated Antideuteron Workshop was organized at UCLA in March 2019, bringing together a community of theorists and experimentalists to review the status of current observations of cosmic-ray antinuclei, the theoretical work towards understanding these signatures, and the potential of upcoming measurements to illuminate ongoing controversies. This review aims to synthesize this recent work and present implications for the upcoming decade of antinuclei observations and searches. This includes discussion of a possible dark matter signature in the AMS-02 antiproton spectrum, the most recent limits from BESS Polar-II on the cosmic antideuteron flux, and reports of candidate antihelium events by AMS-02; recent collider and cosmic-ray measurements relevant for antinuclei production models; the state of cosmic-ray transport models in light of AMS-02 and Voyager data; and the prospects for upcoming experiments, such as GAPS. This provides a roadmap for progress on cosmic antinuclei signatures of dark matter in the coming years., Comment: 45 pages, 14 figures

In this work we report the flux of protons and neutral emission measured at the top of the Sierra Negra volcano at 4600 m.a.s.l. (575 g/cm 2 ), in Eastern Mexico. As an example of the capability of the mini-SciCR as a cosmic ray detector we present the Forbush decrease recorded on March 7, 2012. These data were obtained with a cosmic ray detector prototype called mini-SciCR that was operating from October 2010 to July 2012. Our main aims were to measure the hadronic component flux of the secondary cosmic ray and to show the appropriate performance of all system of the detector. To separate the signals of protons from other charged particles we obtained the energy deposition pattern when they cross the detector using a Monte Carlo simulation, and to separate the signals of neutral emission we used an anticoincidence system between the edge bars and the internal bars of the detector. The mini-SciCR is a prototype of a new cosmic ray detector called SciBar Cosmic Ray Telescope (SciCRT) installed in the same place, which is in the process of calibration. The SciCRT will work mainly as a Solar Neutron and Muon Telescope, it is designed to achieve: (1) larger effective area than the current Solar Neutron Telescope, (2) higher energy resolution to determine the energy spectrum of solar neutrons, (3) lower energy threshold, and (4) higher particle identification ability.

© 2019 IEEE. Large-area lithium-drifted silicon (Si(Li)) detectors, operable 150°C above liquid nitrogen temperature, have been developed for the General Antiparticle Spectrometer (GAPS) balloon mission and will form the first such system to operate in space. These 10 cm-diameter, 2.5 mm-thick multi-strip detectors have been verified in the lab to provide < 4 keV FWHM energy resolution for X-rays as well as tracking capability for charged particles, while operating in conditions (~-40C and ~1 Pa) achievable on a long-duration balloon mission with a large detector payload. These characteristics enable the GAPS silicon tracker system to identify cosmic antinuclei via a novel technique based on exotic atom formation, de-excitation, and annihilation. Production and large-scale calibration of ~1000 detectors has begun for the first GAPS flight, scheduled for late 2021. The detectors developed for GAPS may also have other applications, for example in heavy nuclei identification.

We have developed large-area lithium-drifted silicon (Si(Li)) detectors to meet the unique requirements of the General Antiparticle Spectrometer (GAPS) experiment. GAPS is an Antarctic balloon-borne mission scheduled for the first flight in late 2020. The GAPS experiment aims to survey low-energy cosmic-ray antinuclei, particularly antideuterons, which are recognized as essentially background-free signals from dark matter annihilation or decay. The GAPS Si(Li) detector design is a thickness of 2.5 mm, diameter of 10 cm and 8 readout strips. The energy resolution of 1000 10-cm diameter Si(Li) detectors to achieve high sensitivity to rare antideuteron events, high-yield production is also a key factor for the success of the GAPS mission., submitted to IEEE NSS/MIC 2018 Proceedings

We analyze the Sun's shadow observed with the Tibet-III air shower array and find that the shadow's center deviates northward (southward) from the optical solar disc center in the "Away" ("Toward") IMF sector. By comparing with numerical simulations based on the solar magnetic field model, we find that the average IMF strength in the "Away" ("Toward") sector is $1.54 \pm 0.21_{\rm stat} \pm 0.20_{\rm syst}$ ($1.62 \pm 0.15_{\rm stat} \pm 0.22_{\rm syst}$) times larger than the model prediction. These demonstrate that the observed Sun's shadow is a useful tool for the quantitative evaluation of the average solar magnetic field., 7 pages, 4 figures

著者人数: The Tibet ASγ Collaboration 81名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 小財, 正義), Number of authors: The Tibet ASγ Collaboration 81 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Kozai, Masayoshi), Accepted: 2018-05-03, 資料番号: SA1180049000

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., 4 pages, 3 figures, The 39th International Conference on High Energy Physics (ICHEP2018), Seoul, Korea

The angular displacement of the center of the observed Sun's shadow from the center of the optical solar disc tells us the information of average solar magnetic field strength in the space between the Sun and the Earth. We analyze the displacement of the Sun's shadow observed in 5 ~ 240 TeV cosmic-ray intensity with the Tibet-III air shower array during 10 years between 2000 and 2009, and compare with the MC simulations based on the coronal magnetic field model and Parker's spiral interplanetary magnetic field model. We find that the observed North-South displacement is significantly larger than the prediction of simulations. This result uniquely suggests the underestimation of the average field strength between the Sun and the Earth in our model. In this work, we will report the actual solar magnetic field strength evaluated from the observed Sun's shadow.

We built a large (approximately 4,000 m**2) water Cherenkov- type muon detector array under the existing Tibet air shower array at 4,300 m above sea level, to observe 10-1000 TeV gamma rays from cosmic-ray accelerators in our Galaxy with wide field of view at very low background level. A gamma-ray induced air shower has significantly less muons compared with a cosmic-ray induced one. Therefore, we can effectively discriminate between primary gamma rays and cosmic-ray background events by means of counting number of muons in an air shower event by the muon detector array. We make a status report on the experiment.

Interplanetary shocks are caused both by interplanetary counterparts of coronal mass ejections (ICMEs) and by co-rotating interaction regions (CIRs) propagating in the interplanetary medium. CIRs are formed by the interaction between high-speed and slow solar wind streams. When the interplanetary disturbance propagates faster than the magnetosonic wave speed, in the solar wind frame, a shock wave is formed. Shocks frequently produce decreases of cosmic rays observed both by neutron monitors and muon detectors located at the Earth’s surface. In this work, we analyze this kind of modulation of high-energy cosmic rays (> 50 GeV) observed by the Global Muon Detector Network (GMDN). After correcting both the atmospheric temperature and pressure effects, we calculated the isotropic intensity and the anisotropy vector. From a list of 38 interplanetary shocks identified in 2015 using interplanetary magnetic field and plasma parameters, we performed a superposed epoch analysis grouping the events by type and orientation of shocks. We found that the cosmic ray isotropic intensity is higher when it is associated to fast forward shocks when compared to fast reverse shocks. We also identified some differences in the anisotropy vector when comparing different types of shocks or shocks that are quasi-perpendicular with the remaining ones.

The SciBar Cosmic ray telescope (SciCRT) is installed on the top of the Sierra Negra volcano with the main goal of observing solar neutrons to investigate the ion acceleration process during solar flares. Using scintillator bars as a medium to stop energetic particles, the SciCRT is capable of recording both energy deposited on the bars and direction of the incoming particles with high resolution. The original DAQ system was used in neutrino oscillation experiment (low event rate), therefore operation of the electronics on cosmic ray experiment is limited. To improve the SciCRT performance as a solar neutron telescope, development of custom made DAQ electronics is essential. Our first step onto this task was the design and construction of a new fast readout back-end board using SiTCP. The installation of this new system on Sierra Negra and its further improvement on the data acquisition for the detector will be analyzed on separate paper on this conference. The development of new front end electronics is the next stage of the upgrading process. To achieve this goal, we are developing new electronics applying the time over threshold (ToT) technique, using a FPGA to process the signal from one 64 channel multi anode photomutiplier tube (MAPMT). In this paper we will present the details of this new system and several tests performed to guarantee its proper operation to detect solar neutrons.

The SciBar Cosmic Ray Telescope (SciCRT) is aimed to help elucidate the acceleration mechanism of high-energy ions that may produce neutrons at the Sun. It is a fully active scintillator tracker which consists of 14,848 plastic scintillator bars, originally constructed for accelerator neutrino oscillation experiments. The SciCRT; it has a huge detector volume compared with conventional Solar Neutron Telescopes (SNTs), e.g. 15 times larger than Mexico SNT. Furthermore, the SciCRT can measure the energy deposition of each particle as neutron ADC data which have not been registered before. Neutron ADC data provide us with a precise measurement of energies deposited at the detector. The SciCRT was deployed at the summit of Mt. Sierra Negra (4,600 m) and began to acquire data in September 2013. Then we partially upgraded the DAQ system developed originally for an accelerator experiment, as the readout rate of the DAQ system was significantly limited for our experiment. This paper highlights sensitivity numerical studies of solar neutrons that the SciCRT is able to register. At first, we focus in the accuracy to determine the spectrum power-law index, assuming an instantaneous emission of solar neutrons. This is required to determine the power-law index within an error of ±1.0 in order to discuss the efficiency of the acceleration. Then in the case of the fixed power-law index, we discuss the capability of discriminating three different lengths of emission times: 0 min, 5 min, and 8 min. Finally we evaluate whether it is possible to discriminate a different combination of these two parameters simultaneously. Thus, we show that data from the SciCRT will unlock the degeneracy problem amid the emission time and the energy spectrum of solar neutrons.

We continuously observed the Sun’s shadow in 3 TeV cosmic-ray intensity with the Tibet-III air shower array since 2000. We find a clear solar-cycle variation of the deficit intensity in the Sun’s shadow during the periods between 2000 and 2009. The MC simulation of the Sun’s shadow based on the coronal magnetic field model does not well reproduce the observed deficit intensity around the solar maximum. However, when we exclude the transit periods during ICMEs towards to the Earth, the MC simulation shows better reproducibility. In the present paper, we report on the MC simulation and the analysis method of the Sun’s shadow observed by the Tibet-III array.

We have started a new hybrid air shower experiment at Yangbajing (4300 m a.s.l.) in Tibet in February 2014. This new hybrid experiment consists of the YAC-II comprised of 124 core detectors placed in the form of a square grid of 1.9 m spacing covering about 500 m2, the Tibet-III air shower array with the total area of about 50,000 m2 and the underground MD array consisting of 80 cells, with the total area of about 4,200 m2. This hybrid-array system is used to observe air showers of high energy celestial gamma-ray origin and those of nuclear-component origin. In this paper, a short review of the experiment will be followed by an overview on the current results on energy spectrum and chemical composition of CRs and test of hadronic interaction models.

Solar modulation gives rise to intensity depletion and directional anisotropies in the distribution of galactic cosmic rays (GCRs). These anisotropies are observed to extend into the 100 GV range, where the gyro-radius of GCRs becomes large and the robust diffusive equation of Parker is no longer applicable. We consider both diffusive and non-diffusive models to describe the high-rigidity regime of solar modulation. Our non-diffusive approach employs a model based on calculating energy losses suffered by GCRs along their trajectories through the heliosphere. We track GCR trajectories backward in time. A random magnetic field component is also added to account for scattering. The role of the wavy heliospheric current sheet (HCS) is studied in the two different polarity states of a 22-year magnetic cycle changing the tilt angle of HCS. Simulation results are compared with 44 years of observational data from the Muon Detector in Nagoya (Japan) and Neutron Monitors. We present preliminary simulation data to demonstrate robust qualitative trends. Some implications of the simulation results are discussed.

From three-dimensional spatial density gradient of galactic cosmic rays (GCRs) observed with the Global Muon Detector Network (GMDN), we derive average features of the GCR depleted region behind the IP (interplanetary) shock. We identify 207 IP-shocks that passed the earth based on the geomagnetic storm sudden commencements (SSCs) and extract 50 events that are associated with solar coronal mass ejections (CMEs) in a period between 2006 and 2014. From the first order GCR anisotropy corrected for the solar wind convection and Compton-Getting effect arising from the earth’s orbital motion, we deduce the density gradient on an hourly basis for each event. We then derive the average temporal variation of the density gradient by superposing its variations at the SSC onset timing. We confirm that the density gradient components are clearly enhanced after the shock passage, indicating the existence of GCR depleted region behind the shock which causes the Forbush Decrease in the cosmic ray intensity. The enhancement of the radial gradient shows longer duration when the earth has encountered the western flank of the shock, implying an asymmetric shielding effect of the shock on the GCRs. The longitudinal gradient, on the other hand, shows that the GCR density minimum is located around the longitudinal center behind the shock, which can be ascribed to the centered ejecta driving IP-shock.

We have upgraded the new Tibet ASgamma experiment in China since 2014 to measure the chemical composition of cosmic rays around the knee. This hybrid experiment consist of an air-shower-core detector array (YAC-II) to detect high energy electromagnetic component, the Tibet air-shower array (Tibet-III) and a large underground water-Cherenkov muon-detector array (MD). We have carried out a detailed air-shower Monte Carlo (MC) simulation to study the performance of the hybrid detectors by using CORSIKA (version 7.5000), which includes EPOS-LHC, QGSJETII-04, SIBYLL2.1 and SIBYLL2.3 hadronic interaction models. The preliminary results of the interaction model checking above 50 TeV energy region are reported in this paper, and the primary proton and helium spectra in the energy range 50 TeV to 1015 eV was derived from YAC-I data and is smoothly connected with direct observation data at lower energies and also with our previously reported works at higher energies within statistical errors. The knee of the (P+He) spectra is located around 400 TeV. The interaction model dependence in deriving the primary (P+He) spectra is found to be small (less than 25% in absolute intensity, 10% in position of the knee), and the composition model dependence is less than 10% in absolute intensity.

We analyze the temporal variation of the solar diurnal anisotropy of the multi-TeV cosmic-ray intensity observed with the Tibet air shower array from 2000 to 2009, covering the maximum and minimum of the 23rd solar cycle. We comfirm that a remarkable additional anisotropy component is superposed on the Compton-Getting anisotropy at 4.0 TeV, while its amplitude decreases at higher energy regions. In constrast to the additional anisotropy reported by the Matsushiro experiment at 0.6 TeV, we find the residual component measured by Tibet at multi-TeV energies is consistent with being stable, with a fairly constant amplitude of 0.041% ± 0.003% and a phase at around 07.17 ± 00.16 local solar time at 4.0 TeV. This suggests the additional anisotropy observed by the Tibet experiment could result from mechanisms unrelated to solar activities.

A hybrid experiment has been started by the ASγ experiment at Yangbajing (4300m a.s.l.) in Tibet since May 2009, that consists of a high-energy air-shower-core array (YAC-I) and a high-density air-shower array (Tibet-III). In this paper, we report our results to check the hadronic interaction models SIBYLL2.3, SIBYLL2.1, EPOS-LHC and QGSJETII-04 in the multi-tens TeV energy region using YAC-I+Tibet-III experimental data from May 2009 through January 2010. The effective live time is calculated as 106.05 days. The results show that the description of transverse momentum, inelastic cross-section and inelasticity for the 4 hadronic interaction models is consistent with YAC-I experimental data within 15% systematic errors range in the forward region below 100 TeV. Among them, the EPOS-LHC model is the best hadronic interaction model. Furthermore, we find that the H4a composition model is the best one below the 100 TeV energy region.

We analyze the three-dimensional anisotropy of the galactic cosmic ray (GCR) intensities observed independently with a muon detector at Nagoya in Japan and neutron monitors over four solar activity cycles. We clearly see the phase of the free-space diurnal anisotropy shifting toward earlier hours around solar activity minima in A > 0 epochs, due to the reduced anisotropy component parallel to the mean magnetic field. This component is consistent with a rigidity-independent spectrum, while the perpendicular anisotropy component increases with GCR rigidity. We suggest that this harder spectrum of the perpendicular component is due to contribution from the drift streaming. We find that the bi-directional latitudinal density gradient is positive in theA > 0 epoch, while it is negative in the A < 0 epoch, in agreement with the drift model prediction. The radial density gradient of GCRs, on the other hand, varies with a similar to 11 yr cycle with maxima (minima) in solar maximum (minimum) periods, but we find no significant difference between the radial gradients in the A > 0 and A < 0 epochs. The corresponding parallel mean free path is larger in A < 0 than in A > 0. We also find, however, that the parallel mean free path (radial gradient) appears to persistently increase (decrease) in the last three cycles of weakening solar activity. We suggest that simple differences between these parameters in A > 0 and A < 0 epochs are seriously biased by these long-term trends., Article, ASTROPHYSICAL JOURNAL. 791(1):22 (2014)

We derive the long-term variation of the three-dimensional (3D) anisotropy of approximately 60 GV galactic cosmic rays (GCRs) from the data observed with the Global Muon Detector Network (GMDN) on an hourly basis and compare it with the variation deduced from a conventional analysis of the data recorded by a single muon detector at Nagoya in Japan. The conventional analysis uses a north-south (NS) component responsive to slightly higher rigidity (approximately 80 GV) GCRs and an ecliptic component responsive to the same rigidity as the GMDN. In contrast, the GMDN provides all components at the same rigidity simultaneously. It is confirmed that the temporal variations of the 3D anisotropy vectors including the NS component derived from two analyses are fairly consistent with each other as far as the yearly mean value is concerned. We particularly compare the NS anisotropies deduced from two analyses statistically by analyzing the distributions of the NS anisotropy on hourly and daily bases. It is found that the hourly mean NS anisotropy observed by Nagoya shows a larger spread than the daily mean due to the local time-dependent contribution from the ecliptic anisotropy. The NS anisotropy derived from the GMDN, on the other hand, shows similar distribution on both the daily and hourly bases, indicating that the NS anisotropy is successfully observed by the GMDN, free from the contribution of the ecliptic anisotropy. By analyzing the NS anisotropy deduced from neutron monitor (NM) data responding to lower rigidity (approximately 17 GV) GCRs, we qualitatively confirm the rigidity dependence of the NS anisotropy in which the GMDN has an intermediate rigidity response between NMs and Nagoya. From the 3D anisotropy vector (corrected for the solar wind convection and the Compton-Getting effect arising from the Earth’s orbital motion around the Sun), we deduce the variation of each modulation parameter, i.e., the radial and latitudinal density gradients and the parallel mean free path for the pitch angle scattering of GCRs in the turbulent interplanetary magnetic field. We show the derived density gradient and mean free path varying with the solar activity and magnetic cycles.

At the top of the Sierra Negra volcano in eastern Mexico($19.0^\circ$N,$97.3^\circ$W) the SciBar Cosmic Ray Telescope (SciCRT) is installed, one of its main purposes is to detect solar neutrons to investigate the ion acceleration process during intense solar flares. Furthermore, thanks to the design and construction of the SciCRT in the form of small and long scintillation bars, large active volume, high energy resolution, and a fast electronics for data processing, particle identification is possible through the analysis of tracks. Considering these properties, species identification of secondary cosmic ray inside the Earth's atmosphere, at a depth about $600g/cm^2$ is possible. In this work, we present an ad-hoc algorithm constructed to distinguish between particle species that cross the active volume of the detector. The aim is to use pattern recognition methods and event reconstruction to achieve this goal.

Solar neutron telescopes (SNT) were designed and installed on high mountains to study particle acceleration mechanisms in solar surface. Of these, SciBar cosmic ray telescope (SciCRT) is a brand new telescope installed on the top of the Sierra Negra volcano in eastern Mexico ($19^{\circ}$N, $97.3^{\circ}$W) composed of roughly 15000 scintillator bars, capable of detecting solar particles with both high efficiency and energy resolution. SciCRT is also useful to study the anisotropy of galactic cosmic ray muons. The implementation of SciCRT as a cosmic ray telescope began on September 2013, with $5/8$ of the complete detector operative. After that, further improvement of the operating conditions on the place were made in order to maintain a stable data acquisition on the severe atmospheric conditions on high mountain (4600 m). In July 2015 we partially upgrade the DAQ system, installing a $10$ times faster readout back-end electronics. The new system was installed only on $1/8$ of the detector and on the top and bottom layers (working as muon detectors and anti-counters for neutrons). The upgrade was motivated by the limited transfer rate of the original DAQ system, designed for an accelerator experiment. With this new system we expect an improvement on the neutron sensitivity of the SciCRT. In this paper we will detail the operation of the new system and analyze the data obtained to evaluate its performance. We will also explain the plans to continue the upgrading process, installing the new DAQ systems on more layers of the telescope and make estimates of the expected future performance of the SciCRT, evaluated through Monte Carlo simulations.

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. Here we motivate low-energy cosmic ray antimatter searches and discuss the current status of the GAPS experiment and the design of the payload., 8 pags, 3 figures, Proc. 35th International Cosmic Ray Conference (ICRC 2017), Busan, Korea