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GRAPES-3 experiment

Facts for Prelims (FFP)


Source: PHYS.ORG

 Context: The GRAPES-3 experiment, conducted by the Tata Institute of Fundamental Research in Ooty, India, has identified a new feature in the cosmic-ray proton spectrum around 166 tera-electron-volts (TeV), expanding our understanding of cosmic-ray origins and acceleration mechanisms.

  • Cosmic rays, the universe’s most energetic particles, constantly bombard Earth’s atmosphere, producing particle showers.
  • This finding challenges the traditional single power-law description of cosmic rays and could prompt a re-evaluation of existing models.


The GRAPES-3 experiment, also known as the Gamma Ray Astronomy PeV EnergieS phase-3, is a collaboration between the Indian Tata Institute. The experiment is located in Ooty, India and is designed to study cosmic rays. 


The experiment uses an array of air shower detectors and a large area muon detector to study cosmic rays in the energy range from a few TeV to over 10 PeV. The experiment’s goal is to probe the acceleration of cosmic rays in four astrophysical settings.