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GRAPES-3 Air Shower Array

GRAPES-3 (Gamma Ray Astronomy PeV EnergieS 3rd establishment) is a project for cosmic ray study with air shower detector array and large area muon detectors at Ooty in southern India. Its targets are to study about nuclear composition of cosmic ray, high energy gamma-ray astronomy and modulation of solar activity.[citation needed]

It is located at Ooty in Tamil Nadu of southern India (N11.4o, E76.7o, H2200m a.s.l.). It started to observe air showers with 217 scintillators and 560 m² of muon detector in 2000. A scintillator can detect charged particles of showers. They are covered on about 10,000 m² area. Muon detectors can detect muon whose energy is above 109 eV.[citation needed]

GRAPES-3 is collaborative project between India and Japan.[citation needed] The Collaborating Institutes are:


GRAPES-3 has collected data for several years and measured properties of the cosmic ray flux. Diurnal anisotropy was seen in muons[1] and solar ejection effects were noted.[2][3]


  1. ^ MOHANTY, P K; ATRI, D; DUGAD, S R; GUPTA, S K; HARIHARAN, B; HAYASHI, Y; JAIN, A; KAWAKAMI, S; MORRIS, S D; NAYAK, P K; OSHIMA, A; RAO, B S (6 July 2013). "Solar diurnal anisotropy measured using muons in GRAPES-3 experiment in 2006". Pramana. 81 (2): 343–357. Bibcode:2013Prama..81..343M. doi:10.1007/s12043-013-0561-0. 
  2. ^ Kojima, H.; Antia, H.M.; Dugad, S.R.; Gupta, S.K.; Hayashi, Y.; Jagadeesan, P.; Jain, A.; Kawakami, S.; Mohanty, P.K.; Nonaka, T.; Oshima, A.; Rao, B.S.; Shibata, S. (March 2015). "Measurement of the radial density gradient of cosmic ray in the heliosphere by the GRAPES-3 experiment". Astroparticle Physics. 62: 21–29. Bibcode:2015APh....62...21K. doi:10.1016/j.astropartphys.2014.07.003. 
  3. ^ Subramanian, P.; Antia, H. M.; Dugad, S. R.; Goswami, U. D.; Gupta, S. K.; Hayashi, Y.; Ito, N.; Kawakami, S.; Kojima, H.; Mohanty, P. K.; Nayak, P. K.; Nonaka, T.; Oshima, A.; Sivaprasad, K.; Tanaka, H.; Tonwar, S. C. (February 2009). "Forbush decreases and turbulence levels at coronal mass ejection fronts". Astronomy and Astrophysics. 494 (3): 1107–1118. arXiv:0810.2851free to read. Bibcode:2009A&A...494.1107S. doi:10.1051/0004-6361:200809551. 

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