Space
GRAPES-3 (Gamma Ray Astronomy PeV Energies)
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- Context: Researchers from India and Japan used the GRAPES-3 muon telescope to study 22 years of cosmic-ray data. This helped in understanding the Earth’s upper atmosphere and the Sun’s magnetic field.
- Muons are tiny particles formed when cosmic rays hit gases like oxygen and nitrogen in the atmosphere.
About GRAPES-3
- GRAPES-3 (Gamma Ray Astronomy PeV EnergieS–Phase 3) is a cosmic ray observatory situated at Ooty, Tamil Nadu, at an elevation of nearly 2,200 metres above sea level.
- It is managed by the Tata Institute of Fundamental Research (TIFR).
Objective
- The facility is intended to investigate the origin, acceleration, and propagation of cosmic rays.
Working
- GRAPES-3 examines extensive air showers, which are streams of secondary particles generated when high-energy cosmic rays or gamma rays interact with the Earth’s atmosphere.
- It detects particles in the tera-electronvolt (TeV) to peta-electronvolt (PeV) energy range, representing some of the highest-energy particles found in nature.
Other Areas of Study
- Apart from cosmic rays, the observatory also focuses on:
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- Solar phenomena, especially the effects of solar activity on cosmic rays.
- Thunderstorm-related processes, including atmospheric electric fields and their interaction with cosmic ray muons.
- The observatory employs:
- A network of plastic scintillator detectors to record extensive air showers.
- A large area muon detector based on proportional counters to detect high energy muons reaching the Earth’s surface.

