Japan-Australia Cooperative Observation of North-South Asymmetry in Intensity Variation of High Energy Cosmic Rays(r1012/!V)

Japan-Australia cooperative observation between Shinshu University and University of Tasmania commenced in December 1991 to measure the north-south (N-S) asymmetry in the intensity variation of high energy cosmic rays (d1012/!V). In the project an emphasis is particularly laid on the measurement of the N-S asymmetric sidereal anisotropy to reveal three-dimensional nature of anisotropies of galactic origin. This is the first bi-hemisphere comparative underground observation, and was motivated on the basis of recent data obtained by multi-directional telescopes at Matsushiro (220 m.w.e. depth underground) of Shinshu University and at Sakashita (80 m.w.e. depth underground) of Nagoya University. The data show that at rigidities ～400 GV to ～1 TV, the observed diurnal amplitudes appear to increase as the detector's latitude of viewing moves southward, suggesting its N-S asymmetric nature of the sidereal time variation. The evidence is, however, limited only in the northern hemisphere, and has no positive confirmation yet in the southern hemisphere. To get further information about the N-S asymmetric anisotropy, Japanese group proposed the bi-hemisphere comparative observation with similar equipments and at similar rigidities. Two cosmic ray groups of Shinshu University and University of Tasmania, Australia agreed with each other, both financially supported, to push a joint project and open a pair underground stations; one at Matsushiro (in operation since 1984), Japan and the other at Liapootah (newly constructed) in Tasmania, Australia. The Liapootah underground station (42°20'S, 146°28'E) is situated in a central part of Tasmania Island, and has such characteristics as; located at almost conjugate position to Matsushiro (36°32' N, 138°01' E), at almost comparable underground depth (approximately 154 m.w.e.) to Matsushiro (220 m.w.e. depth), and with almost similar rigidities of primaries (～500 GV-1 TV). The muon telescope used at Liapootah is quite similar to that at Matsushiro; of plastic scintillators viewed with double photomultipliers and of multi-directional. Nearly equal counting-rates of muons are obtained at two stations ; ～2・ 10t /hr for the vertical telescope, and 5-7・103/hr for the inclined telescope (towards north-, south-, east- and west-direction). In the present paper, we describe the underground site and the muon telescope at Liapootah in some details, with a comparsion of those at Matsushiro. All the electronics system including data sending are controlled by means of the micro-computer system via public telephone lines from both universities at Hobart and Matsumoto.Article信州大学理学部紀要 27(2): 47-78(1993)departmental bulletin pape

Atmospheric temperature effect on Cosmic Ray count rate observed at Syowa Station in Antarctic

The Tenth Symposium on Polar Science/Special session: [S] Future plan of Antarctic research: Towards phase X of the Japanese Antarctic Research Project (2022-2028) and beyond, Tue. 3 Dec. / Entrance Hall (1st floor) at National Institute of Polar Research (NIPR

A new cosmic ray observation at Syowa Station in the antarctic

A set of Cosmic Ray detectors was newly installed in Syowa Station, in the Antarctic, to observe CR neutrons and muons simultaneously at the same location. The observing system has started working in February 2018 and is in stable operation with a high operation rate, >90%. We describe the new systems and show its stability

南極昭和基地での宇宙線観測による宇宙天気研究の新展開

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所 2階 大会議

MHD Modeling of the Outer Heliospheric Structures

第6回極域科学シンポジウム[OS] 宙空圏11月16日（月）　国立極地研究所 2階 大会議

The Global Muon Detector Network - GMDN. The Brazilian Contribution for Space Weather Forecasting

The GMDN, is a Global Muon Detector Network (GMDN) of ground based multi-directional detectors, and an international collaboration consisting of 10 institutions from 6 countries, with real time data generated by the GMDN, which was developed at Shinshu University, Japan. The Brazilian GMDN’s contribution was the installation in 2001, of a Multi-Directional Muon Detector prototype (MMD) for detection of high-energy galactic cosmic rays (GCRs), through an international cooperation between Brazil, Japan and USA, and has been in operation since then at the Southern Space Observatory - SSO/CRS/INPE - MCTI, (Latitude 29o, 26’, 24”S, Longitude 53o, 48’, 38”W, 492m above sea level), S˜ao Martinho da Serra, RS, in southern Brazil. The SSO-MMD detector’s capability and sensitivity were twice upgraded, in 2005 and 2012. The Brazilian contribution for Space Weather forecasting is through the observations conducted by the SSO-MMD which are used for forecasting the arrival of the geomagnetic storm and their Interplanetary Coronal Mass Ejection (ICME) drivers in the near-Earth geospace. The detector measures GCRs by detecting secondary muons produced from the hadronic interactions of primary GCRs (mostly protons) with atmospheric nuclei. Since muons have a relatively short life-time (about 2.2 microseconds at rest), it can reach the ground level due to the relativistic effect, and can preserving the incident direction of primary particles, because its high energy, the SSO-MMD detector can measure the GCRs intensity in 17 directions as a multidirectional detector at a single location, the SSO in southern Brazil