Recently, China has completed its Jiangmen Underground Neutrino Observatory (JUNO) and released initial research findings, while India’s India-based Neutrino Observatory (INO) remains stalled after years of delays.

What are Neutrinos?

• Basic Definition: Neutrinos are subatomic particles that have no electrical charge and negligible mass (very small but nonzero mass).
• Ghost Particles: These particles are so elusive that about 100 trillion neutrinos pass through the human body every second without being noticed.
• Leptons Family: Neutrinos are part of the lepton family of particles of the Standard Model of particle physics, which do not interact through the strong nuclear force. Instead, they interact via the weak nuclear force, making them extremely difficult to detect.
• Types or Flavours of Neutrinos: Neutrinos exist in three types, or flavours: electron neutrino, muon neutrino, and tau neutrino.
• Oscillation:  As they travel, neutrinos can change (oscillate) from one flavour to another.

Properties of Neutrinos

• Extremely small mass: While the exact mass is still undetermined, it is known to be tiny compared to other subatomic particles like electrons.
• No electric charge: Neutrinos have no charge, making them interact very weakly with matter.
• Speed: Neutrinos travel at speeds very close to the speed of light, essentially in straight lines from their point of origin. 
• Weak interaction: They interact only via the weak nuclear force and gravitational force, making them highly penetrative.
• Messengers of Information: Due to their unique properties, neutrinos serve as excellent messengers, conveying information about the events or objects from which they originate.

Sources of Neutrinos

• Cosmic Events: High-energy neutrinos are produced in events such as supernovas, as well as in objects like active galactic nuclei and black holes.
• Other Sources: Neutrinos are also released during nuclear reactions in the Sun, particle decay on Earth, beta decay, particle accelerators, and nuclear power plants.

Significance of Studying Neutrinos

• Understanding the Universe’s Evolution: Neutrinos can offer insights into the early stages of the universe, providing clues about the period shortly after the Big Bang.
• Dark Matter and Dark Energy: Neutrinos help researchers understand dark matter (27%) and dark energy (68%), which together make up 95% of the universe’s total composition.
• Applications: Neutrinos have the potential to be used in medical imaging, similar to technologies like X-ray machines and MRI scans.

India- based Neutrino Observatory (INO)

• Proposed site: 
  • The proposed site for the India-based Neutrino Observatory (INO) is located in Theni district, Tamil Nadu, where the observatory will be situated underground inside a mountain. 
  • This location provides an ideal environment for the study of neutrinos due to its natural shielding from external disturbances.
• Detector: The INO will feature a 50 kiloton Iron Calorimeter (ICAL) detector, which is designed to detect and measure atmospheric neutrinos with high precision
• Purpose: The primary goal of the INO is to study atmospheric neutrinos and to determine the neutrino mass hierarchy.
• Advantages:
  • The mountain rock at the proposed site will serve as a natural shield from cosmic rays, which is beneficial for the accurate detection of neutrinos. 
  • This protection reduces interference from cosmic radiation, allowing for clearer data collection.
• Funding: Jointly funded by the Department of Atomic Energy and Department of Science & Technology.

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