H. Kojima

Performance of the SciBar cosmic ray telescope (SciCRT) toward the detection of high-energy solar neutrons in solar cycle 24

We plan to observe solar neutrons at Mt. Sierra Negra (4,600 m above sea level) in Mexico using the SciBar detector. This project is named the SciBar Cosmic Ray Telescope (SciCRT). The main aims of the SciCRT project are to observe solar neutrons to study the mechanism of ion acceleration on the surface of the sun and to monitor the anisotropy of galactic cosmic-ray muons. The SciBar detector, a fully active tracker, is composed of 14,848 scintillator bars, whose dimension is 300 cm × 2.5 cm × 1.3 cm. The structure of the detector enables us to obtain the particle trajectory and its total deposited energy. This information is useful for the energy reconstruction of primary neutrons and particle identification. The total volume of the detector is 3.0 m × 3.0 m × 1.7 m. Since this volume is much larger than the solar neutron telescope (SNT) in Mexico, the detection efficiency of the SciCRT for neutrons is highly enhanced. We performed the calibration of the SciCRT at Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) located at 2,150 m above sea level in Mexico in 2012. We installed the SciCRT at Mt. Sierra Negra in April 2013 and calibrated this detector in May and August 2013. We started continuous observation in March 2014. In this paper, we report the detector performance as a solar neutron telescope and the current status of the SciCRT.

Transient weakening of geomagnetic shield probed by GRAPES-3 experiment

The large area (560 m

Diffusion of cosmic rays in heliosphere, observations from GRAPES-3

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Atmospheric temperature dependence of muon intensity measured by the GRAPES-3 experiment

) GRAPES-3 tracking muon telescope in Ooty, India recorded a 2 hour (h) muon burst on 22 June 2015 starting at 19:00 UT in the midst of a continuing Forbush decrease. The burst occurred following the arrival of a coronal mass ejection containing a 40 nT south-ward interplanetary magnetic field (IMF) that had triggered a G4 class geomagnetic storm. During the 2 hour, the muon telescope recorded an excess of

Extending the range of particle densities observed by GRAPES-3

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Long-term correction of GRAPES-3 muon telescope efficiency

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Measuring the hourly gain of the scintillator detectors from EAS data

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Precision measurement of arrival times in an EAS by GRAPES-3 experiment

muons with a significance of 54

Transient Weakening of Earth’s Magnetic Shield Probed by a Cosmic Ray Burst

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Fast Fourier transform to measure pressure coefficient of muons in the GRAPES-3 experiment

. Simultaneous occurrence of the burst was observed in 9 directions covering 2.3 sr field of view suggesting its origin close to Earth.Trajectory computation of cosmic ray primary protons followed by atmospheric simulation by superimposing the 2 hour IMF variation on geomagnetic field (GMF) could reproduce the observed profiles with a high degree of correlation (0.89