Why in News?
The GRAPES-3 Telescope is in the news because an international team of researchers from India and Japan published a groundbreaking study utilizing 22 years of continuous data collected by the observatory.
Overview & Name
- The study successfully mapped how the temperature of Earth’s upper atmosphere and variations in the Sun's magnetic field directly influence the intensity of muons—highly penetrating subatomic particles arriving from deep space.
- Full Name: Stands for Gamma Ray Astronomy PeV EnergieS phase-3 (GRAPES-3).
- Facility Type: It is an advanced cosmic-ray observatory and muon telescope that tracks high-energy particles rather than capturing visible starlight.
- Primary Objective: Designed to explore the origin, acceleration mechanisms, and propagation of high-energy cosmic rays and diffuse gamma rays traversing the universe.
Geographical Location & Operation
- Location: Situated in the scenic hills of Ooty, Tamil Nadu, India, at a high altitude of 2,200 metres above mean sea level.
- Key Operators: Maintained and operated primarily by the Tata Institute of Fundamental Research (TIFR) in collaboration with multiple Indian and Japanese scientific institutions.
Advanced Detector Infrastructure
- Dual-Component Design: The observatory features a large, dense ground grid spread over an expansive footprint of 25,000 square metres.
- Scintillator Array: Equipped with roughly 400 plastic scintillator detectors that sense charged particles generated during extensive air showers in the sky.
- Muon Tracker: Houses the world’s largest area muon telescope, covering 560 square metres across 16 modular units and utilising roughly 4,000 gas-filled proportional counters.
The Science of Muons & Cosmic Rays
- Cosmic Rays: High-energy charged particles bombarding Earth uniformly from outer space, originating from volatile sources like supernovas or active galaxies.
- Muons: Subatomic particles resembling electrons but possessing significantly greater mass. They are generated when primary cosmic rays violently collide with molecules in Earth's upper atmosphere.
- Detection Process: When a muon passes through the gas tubes of the telescope, it ionises gas molecules to generate distinct electrical signals, mapping the particle's cosmic pathway.
Major Past Discoveries & Milestones
- Spectral Kink Discovery: The telescope identified a unique, unexpected "kink" or deviation in the cosmic-ray proton spectrum at 166 Tera-Electron-Volt (PeV) energy.
- Gigavolt Thunderstorm Potential: GRAPES-3 holds the world record for measuring a massive 1.3 Gigavolt electrical potential inside a 400-square-kilometre thundercloud using advanced muon imaging.
- Magnetic Shield Defect: The array previously discovered a temporary "crack" in Earth's protective magnetic shield caused by a severe solar storm burst.
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